JP6447847B2 - Resistance welding equipment - Google Patents

Description

  The present invention relates to a resistance welding apparatus that performs spot welding on an object to be welded (for example, a plate set formed by superposing at least two steel sheets), and more particularly, to a resistance welding apparatus including a one-side electrode.

  Conventionally, the above-described anti-welding apparatus includes a so-called stationary type (for example, see Patent Document 1) and a table type (for example, see Patent Document 2). A stationary resistance welding apparatus sandwiches an object to be welded between two electrodes, an upper part and a lower part, which are arranged to face each other, and performs welding while applying current while applying pressure. A table-type resistance welding apparatus has a table-shaped electrode (hereinafter referred to as a “table electrode”) at the bottom and a gun-type electrode that can be moved up, down, left, and right, and places an object to be welded on the table electrode. The tip of the gun-type electrode is brought into contact with the welding point of the workpiece, and welding is performed by applying current while applying pressure.

  Further, in recent years, rather than sandwiching a workpiece to be welded between two separate electrodes, welding is performed with respect to the workpiece from one direction (mainly upward) with respect to the workpiece. Many so-called one-side welding inventions in which welding is performed by pressing (see, for example, Patent Documents 3 and 4).

  Here, the one-side electrode will be described with reference to the welding apparatus described in Patent Document 4. 16-19 is a figure for demonstrating the use condition of the welding apparatus described in patent document 4. As shown in FIG. As shown in FIGS. 16 and 17, the one-side electrode 85 is energized with a gun body 72 that supports the inner electrode 85A, an inner electrode 85A having an insulating ring 85C disposed at the tip, and an inner side on the outer peripheral side of the inner electrode 85A. An electrode 85A and an outer electrode 85B arranged coaxially are provided. The outer electrode 85B is integrated with the sliding conductor 73 and moves in the axial direction by the sliding conductor 73 (that is, moves toward the workpiece 500). The gun body 72 and the sliding conductor 73 constitute the welding gun 6. Between the gun main body 72 and the sliding conductor 73, a linear motion guide 80 is provided for connecting them and guiding the sliding conductor 73 with respect to the gun main body 72.

  A workpiece 500 is a plate assembly formed by superposing two steel plates 500a and 500b, and an upper steel plate (hereinafter referred to as “upper steel plate”) 500a at a welding location is shown in FIG. A relief hole 550 as shown is formed. As shown in FIGS. 17 and 18, the tip of the inner electrode 85A presses the lower steel plate (hereinafter referred to as “lower steel plate”) 500b inside the escape hole 550, and then the outer electrode 85B is welded. The opening peripheral edge of the escape hole 550 of the steel plate 500a of the object 500 is pressed. A plurality of (three in FIG. 19) projections 551 as shown in FIG. 19A are formed at the joint of the workpiece 500, and the inner electrode 85A presses the lower steel plate 500b. In a state where the outer electrode 85B presses the upper steel plate 500a, power is supplied between the outer electrode 85B and the inner electrode 85A, so that the outer electrode 85B → the projection 551 of the upper steel plate 500a → the lower steel plate 500b → the inner electrode. A current flows through a path of 85A, whereby the upper steel plate 500a and the lower steel plate 500b of the workpiece 500 are welded.

  By the way, the above-described welding gun 6 is constructed such that the gun main body 72 can be welded so that welding can be performed even when the upper end portion 500b1 such as the lower steel plate 500b of the workpiece 500 shown in FIG. The sliding conductor 73 is L-shaped. By adopting such a structure, if the upper end portion (not shown) on the opposite side of the workpiece 500 is also bent inward, welding can be performed by reversing the welding gun 6 180 degrees around the axis. . However, when the welding gun 6 can be rotated around the axis, a means for electrically connecting the apparatus main body side and the welding gun 6 side is required around the rotation mechanism portion, and at present, a power feeding cable is used as the means. (Also called “resistance welding cable”, “secondary cable”, etc.).

  When a power supply cable is used for electrical connection between the apparatus main body and the welding gun 6 side, the power supply cable may be tangled during use of the welding apparatus. Further, since a large current flows in resistance welding, a power feeding cable having a large cross-sectional area is required, which increases the weight of the power feeding cable and makes it difficult to handle the welding gun 6. For such a problem, there is a power supply device described in, for example, Patent Document 5 as an apparatus that can perform electrical connection between the apparatus main body side and the welding gun 6 side without using a power supply cable. The power feeding device described in this document is a welding machine in which a welding current is supplied from a transformer to a pressurizing shaft having an electrode at the tip via a power supply electron, and is welded to the welding machine body in parallel with the welding machine body. The transformer is fixed, the secondary terminal of the transformer is connected to the power supply housing formed in the main body of the welder, and a ring-shaped groove is formed in the power supply housing toward the pressure shaft. An oblique winding coil spring is accommodated, and the oblique winding coil spring is brought into contact with the power supply housing and the pressure shaft to supply electrons.

JP 2002-239746 A Japanese Patent Laid-Open No. 06-328265 JP 2011-031269 A JP 2017-035707 A JP 2010-131660 A

  However, in the power supply apparatus described in Patent Document 5, a pressure is applied between the power supply housing and the pressure shaft by the restoring force of the diagonally wound coil spring so as to press the power supply housing and the pressure shaft. However, there is a risk that the pressure welding with only the restoring force of the diagonally wound coil spring cannot withstand the reaction when a large current is passed. For example, when welding a steel sheet with a protective sheet on the back side or a steel sheet with a coating on the back side, a large current should flow for a very short time so that the protective sheet will not burn or the coating will not be discolored. However, there is a possibility that the large current at this time cannot be handled by the above-described prior art power supply device.

  Although it is not impossible to reduce the recoil when a large current is applied by tightening the power supply housing against the pressure shaft using a spring with a large restoring force, it is not impossible to tighten the pressure shaft by strengthening the tightening force. It becomes difficult to move.

  The present invention has been made in view of the circumstances, and can eliminate the power supply cable connecting between the fixed portion and the movable portion in the rotation mechanism portion for rotating the welding gun while allowing the welding gun to rotate around the axis. An object of the present invention is to provide a resistance welding apparatus capable of stably flowing a large current between the fixed portion and the movable portion.

In the resistance welding apparatus of the present invention, the gap 12a is divided into a plurality of portions in the annular magnetic core 25 constituted by the parallel portion 25a and the U-shaped curved portions 25b at both ends, and the parallel portion 25a of the annular magnetic core 25. A primary coil 12 that is split and wound, and the primary coil 12 and the parallel part 25a of the annular magnetic core 25 are wound together with the primary coil 12, and are sandwiched one by one in the gaps 12a provided in the primary coil 12. Thus, the secondary coil 15 in which a plurality of positive side coils 14 and a plurality of negative side coils 16 are alternately arranged, and the plurality of positive side coils 14 are all connected in parallel or all or part of them are connected in series. The plurality of negative coils 16 are all connected in parallel or all or part of them are connected in series, and the plurality of connected positive coils 14 and the plurality of negative coils 16 are directly connected to each other. A conductor group electrically connecting the terminals of the positive side coil 14 and the negative side coil 16 so as to be connected, and the positive side coil 14 and the negative side coil are all connected by the conductor group. 16 on one surface, and one terminal of the plurality of positive side coils 14 is connected to the parallel portion 25a of the annular magnetic core 25 on the other surface of the connection substrate 62. Are electrically connected to a first connecting pole plate 44 extending in a direction parallel to the first connecting pole plate 44, and one terminal of the plurality of negative coils 16 is connected to the parallel portion of the annular magnetic core 25 on the other surface side of the connecting board 62. The other end of the positive side coil 14 and the negative side coil 16 are both on the other surface side of the connection board 62 and connected to the second connecting electrode plate 46 extending in a direction parallel to 25a. Stretching in a direction parallel to the parallel portion 25a of the magnetic core 25 The first connecting electrode plate 44 is connected to the positive conductor 30, the second connecting electrode plate 46 is connected to the negative conductor 32, and the positive electrode 30 is connected to the third connecting electrode plate 48. The pair of side conductors 30 and the negative side conductors 32 are overlapped on the other surface side of the connection substrate 62 via an insulating layer 31 disposed on a boundary surface extending in a direction away from the other surface. A rectifying element 18 sandwiched between the positive conductor 30 and the first electrode plate 34 and having a negative electrode in contact with the positive conductor 30 and a positive electrode in contact with the first electrode plate 34; The rectifying element 20 sandwiched between the negative conductor 32 and the second electrode plate 36, the negative electrode being in contact with the negative conductor 32, and the positive electrode being in contact with the second electrode plate 36, and the first electrode plate 34 A third electrode plate 38 that supports the second electrode plate 36 and electrically connects them, and the third electrode plate 38. The welding transformer 10 including the positive electrode 22 connected to the negative electrode 22 and the negative electrode 24 connected to the third connecting electrode plate 48, and both the distal end portion 72A and the proximal end portion 72B are bent at right angles in the same direction. The U-shaped gun main body 72 and both end portions of the gun main body 72 are disposed close to the second surface opposite to the first surface bent at a right angle, along the longitudinal direction of the second surface. An L-shaped sliding conductor 73 that is slidable and has a length that reaches the distal end of the gun body 72 while the distal end portion 73A bends at right angles to the distal end portion 72A of the gun body 72. A welding gun 6A to which a current output from the welding transformer 10 is supplied via the power supply cable 7, a distal end portion 72A of the gun body 72 of the welding gun 6A , and a distal end portion 73A of the sliding conductor 73. Over A cylindrical inner electrode 85A which is electrically connected to the gun body 72 and provided with an insulating ring 85C at the tip thereof, and is cylindrical, integrated with the sliding conductor 73, and axially In the resistance welding apparatus including the one-side electrode 85 configured by the outer electrode 85B into which the electrode 85A can be inserted, the welding gun 6A is made of a cylindrical conductive metal member, and is connected via the feeding cable 7 The first fixed shaft 741 connected to the negative electrode 24 of the welding transformer 10 and a cylindrical conductive metal member, and the first fixed shaft 741 is maintained in a non-conductive state with the first fixed shaft 741. 741 can be inserted, and includes a second fixed shaft 742 connected to the plus electrode 22 of the welding transformer 10 via the power supply cable 7, and includes the gun body 72 and the sliding conductor 73. , A fixed shaft portion 74 for rotatably supporting a central axis common with the first fixed shaft 741 to the second fixed shaft 742 as a rotation center, of the gun body 72 and the fixed shaft portion 74 of the welding gun 6A A first feeding device 76 disposed between and electrically connecting the first fixed shaft 741 of the fixed shaft portion 74 and the gun body 72; and the sliding conductor 73 of the welding gun 6 and the fixing. A second power feeding device 77 disposed between the shaft portions 74 and electrically connecting the second fixed shaft 742 of the fixed shaft portion 74 and the sliding conductor 73; Each of the device 76 and the second power feeding device 77 has a three-dimensional shape having a concave shape in plan view, and the recessed portion is formed as a semicircular groove, and the first block body 761 made of a conductive metal member, and the first block body. A semicircular groove consisting of approximately the same shape and the same member as 761 The second block body 762 is disposed so as to face the surface side where the semi-circular groove of the first block body is formed, and the semi-circular groove of the first block body 761 is formed. The first block body 761 and the second block body 762 are separated by a restoring force between the first block body 762 and the second block body 762 in a compressed state. Coil springs 763 and 764 that act on each other, and a cylindrical shape that partially fits with the semicircular grooves of each of the first block body 761 and the second block body 762, and at least an outer peripheral surface and an inner peripheral surface A bush 765 made of a conductive metal member having at least one groove having a length from one opening end to the other opening end on one surface, the first block body 761 and the second block body 7. 2, and a clamping mechanism 766 and 767 for clamping the bush 765 by the first block body 761 and the second block body 762 by pulling at least one of them to the other side, and the first block body 761 and The second block body 762 is collectively referred to as a fixed portion, and a metal member fitted into the bush 762 is referred to as a movable portion. When the current flows between the fixed portion and the movable portion, the clamping mechanism 766 is used. , 767, the conduction between the fixed portion and the movable portion is achieved.

  According to the above configuration, the first power feeding device 76 for energizing the first fixed shaft 741 and the gun body 72, and the second power feeding device 77 for energizing the second fixed shaft 742 and the sliding conductor 73. Therefore, it is possible to omit power supply cables connecting between the first fixed shaft 741 and the gun main body 72 and between the second fixed shaft 742 and the sliding conductor 73, and stable between them. Large current can be applied. As a result, the current from the welding transformer 10 capable of supplying a large current in a short time can be efficiently passed through the one-side electrode 85, and the advantage of the one-side electrode 85 (that is, the cover having a protective sheet attached on one side). In welding of welded materials, it is difficult to generate indentations or heat-induced burns or distortions on the back surface, and in welding of one-side-coated workpieces, it is difficult to generate burns or thermal discoloration). . Further, since a large current can be flowed in a short time, power saving can be achieved.

In the resistance welding apparatus of the present invention, the gap 12a is divided into a plurality of portions in the annular magnetic core 25 constituted by the parallel portion 25a and the U-shaped curved portions 25b at both ends, and the parallel portion 25a of the annular magnetic core 25. A primary coil 12 that is split and wound, and the primary coil 12 and the parallel part 25a of the annular magnetic core 25 are wound together with the primary coil 12, and are sandwiched one by one in the gaps 12a provided in the primary coil 12. Thus, the secondary coil 15 in which a plurality of positive side coils 14 and a plurality of negative side coils 16 are alternately arranged, and the plurality of positive side coils 14 are all connected in parallel or all or part of them are connected in series. The plurality of negative coils 16 are all connected in parallel or all or part of them are connected in series, and the plurality of connected positive coils 14 and the plurality of negative coils 16 are directly connected to each other. A conductor group electrically connecting the terminals of the positive side coil 14 and the negative side coil 16 so as to be connected, and the positive side coil 14 and the negative side coil are all connected by the conductor group. 16 on one surface, and one terminal of the plurality of positive side coils 14 is connected to the parallel portion 25a of the annular magnetic core 25 on the other surface of the connection substrate 62. Are electrically connected to a first connecting pole plate 44 extending in a direction parallel to the first connecting pole plate 44, and one terminal of the plurality of negative coils 16 is connected to the parallel portion of the annular magnetic core 25 on the other surface side of the connecting board 62. The other end of the positive side coil 14 and the negative side coil 16 are both on the other surface side of the connection board 62 and connected to the second connecting electrode plate 46 extending in a direction parallel to 25a. Stretching in a direction parallel to the parallel portion 25a of the magnetic core 25 The first connecting electrode plate 44 is connected to the positive conductor 30, the second connecting electrode plate 46 is connected to the negative conductor 32, and the positive electrode 30 is connected to the third connecting electrode plate 48. The pair of side conductors 30 and the negative side conductors 32 are overlapped on the other surface side of the connection substrate 62 via an insulating layer 31 disposed on a boundary surface extending in a direction away from the other surface. A rectifying element 18 sandwiched between the positive conductor 30 and the first electrode plate 34 and having a negative electrode in contact with the positive conductor 30 and a positive electrode in contact with the first electrode plate 34; The rectifying element 20 sandwiched between the negative conductor 32 and the second electrode plate 36, the negative electrode being in contact with the negative conductor 32, and the positive electrode being in contact with the second electrode plate 36, and the first electrode plate 34 A third electrode plate 38 that supports the second electrode plate 36 and electrically connects them, and the third electrode plate 38. The welding transformer 10 including the positive electrode 22 connected to the negative electrode 22 and the negative electrode 24 connected to the third connecting electrode plate 48, and both the distal end portion 72A and the proximal end portion 72B are bent at right angles in the same direction. The U-shaped gun main body 72 and both end portions of the gun main body 72 are disposed close to the second surface opposite to the first surface bent at a right angle, along the longitudinal direction of the second surface. An L-shaped sliding conductor 73 that is slidable and has a length that reaches the distal end of the gun body 72 while the distal end portion 73A bends at right angles to the distal end portion 72A of the gun body 72. a welding gun 6B with the provided along the distal end portion 73A of the tip portion 72A of the gun body 72 of the welding gun 6B the Suridoshirubedentai 73, conducted to the gun body 72, an insulating the tip ring 85C Circle with An inner electrode 85A having a cylindrical shape, and a one-sided electrode 85 that is formed of a cylindrical electrode and is formed of an outer electrode 85B that is integrated with the sliding conductor 73 and in which the inner electrode 85A can be inserted in the axial direction. In the resistance welding apparatus, the welding gun 6B is made of a cylindrical conductive metal member, one end of which is directly connected to the negative electrode 24A of the welding transformer 10, and a cylindrical conductive material. It is made of a metal member and allows the first fixed shaft 741B to be inserted while maintaining a non-energized state with the first fixed shaft 741B. On the opening end side located on the same side as one end of the first fixed shaft 741B, The gun main body includes an annular flange Ba extending in a direction perpendicular to the central axis direction, and the annular flange Ba includes a second fixed shaft 742B directly connected to the plus electrode 22A of the welding transformer 10. 2 and the sliding conductor 73, a fixed shaft portion 74B that rotatably supports a central axis common to the first fixed shaft 741B and the second fixed shaft 742B, and the fixed shaft portion 74B. A first power feeding device 76 that electrically connects the first fixed shaft 741B and the gun body 72, and a second that electrically connects the second fixed shaft 742B of the fixed shaft portion 74B and the sliding conductor 73. A power supply device 77, each of the first power supply device 76 and the second power supply device 77 has a three-dimensional shape that is concave in plan view, and the recessed portion is formed as a semicircular groove, and is made of a conductive metal member. The first block body 761 is composed of substantially the same shape and the same member as the first block body 761, and the surface side where the semicircular groove is formed is the surface side where the semicircular groove of the first block body is formed. 2nd block arranged facing toward The body 762 is disposed in a compressed state between the surface side of the first block body 761 where the semicircular groove is formed and the surface side of the second block body 762 where the semicircular groove is formed. Coil springs 763 and 764 that act to separate the first block body 761 and the second block body 762 by force, and the semicircular grooves and partial portions of the first block body 761 and the second block body 762, respectively. A bush formed of a conductive metal member that has a cylindrical shape that fits in, and has at least one groove that extends from one open end to the other open end on at least one of the outer peripheral surface and the inner peripheral surface 765, and pulling at least one of the first block body 761 and the second block body 762 to the other side, the first block body 761 and the second block body 7 2, and the first block body 761 and the second block body 762 are collectively referred to as a fixing portion, and a metal member fitted into the bush 762 is provided. When the current is passed between the fixed part and the movable part, the pinching mechanisms 766 and 767 are operated to establish electrical connection between the fixed part and the movable part.

  According to the above configuration, the first power feeding device 76 for energizing the first fixed shaft 741B and the gun body 72, and the second power feeding device 77 for energizing the second fixed shaft 742B and the sliding conductor 73. Since the welding transformer 10 is directly connected to the fixed shaft portion 74B, the welding transformer is connected between the first fixed shaft 741B and the gun body 72, between the second fixed shaft 742B and the sliding conductor 73, and the welding transformer. 10 and the fixed shaft portion 74B can be omitted, and a large current can flow stably between them. Thereby, it becomes possible to flow the current from the welding transformer 10 capable of supplying a large current in a short time to the one-side electrode 85 more efficiently, and the advantage of the one-side electrode 85 (that is, a protective sheet is stuck on one side). When welding workpieces, it is difficult to generate indentations or heat-induced burns or distortions on the back surface, and when welding single-sided workpieces, it is difficult to cause burning or thermal discoloration). it can. Further, since a large current can be flowed in a short time, power saving can be achieved.

  ADVANTAGE OF THE INVENTION According to this invention, a large electric current can be stably sent between the stationary part and movable part in the rotation mechanism part for rotating a welding gun around the axis | shaft.

The side view which shows the external appearance structure of the resistance welding apparatus which concerns on 1st Embodiment of this invention. The side view which shows the detailed structure of the welding gun of the resistance welding apparatus of FIG. The top view which shows the external appearance structure of the 1st electric power feeder of the resistance welding apparatus of FIG. The metal bush of the 1st electric power feeder of the resistance welding apparatus of FIG. 1 is shown, (a) is the external view seen from the axial direction, (b) is the external view seen from the orthogonal direction with respect to the axial direction. The figure which shows the current path at the time of the longitudinal section of each of the 1st, 2nd electric power feeder of the resistance welding apparatus of FIG. The figure which shows schematic structure of the resistance welding apparatus of FIG. The figure which shows the control pulse for controlling the electric current supplied to the primary side of the welding transformer of the resistance welding apparatus of FIG. 1, a primary current, and the welding current after rectification | straightening The figure which shows the connection of the welding transformer and welding gun of the resistance welding apparatus of FIG. The figure which shows circuit operation | movement when a forward current flows into the 1st rectifier of the welding transformer of the resistance welding apparatus of FIG. The figure which shows circuit operation | movement when a forward current flows into the 2nd rectifier of the welding transformer of the resistance welding apparatus of FIG. The perspective view which shows the external appearance of the welding transformer of the resistance welding apparatus of FIG. The perspective view which shows the assembly state of the welding transformer of the resistance welding apparatus of FIG. The side view which shows the external appearance structure of the resistance welding apparatus which concerns on 2nd Embodiment of this invention. The side view which shows the detailed structure of the welding gun of the resistance welding apparatus of FIG. The perspective view which shows the external appearance structure of the welding transformer of the resistance welding apparatus of FIG. The figure for demonstrating the use condition of the welding apparatus described in patent document 4 The figure for demonstrating the use condition of the welding apparatus described in patent document 4 The figure for demonstrating the use condition of the welding apparatus described in patent document 4 The figure for demonstrating the use condition of the welding apparatus described in patent document 4

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments for carrying out the invention will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 is a side view showing an external configuration of a resistance welding apparatus 1A according to the first embodiment of the present invention. In the figure, a resistance welding apparatus 1A according to the first embodiment includes a cooling unit 2, a power supply unit 3, a support post 4, a support arm 5, a welding gun 6A , a power supply cable 7, and a gun shaft 8. The table 9, the welding transformer 10, the welding condition setting device 11, the handle 65, the power feeding device 66, and the pressurizing device 67 are provided.

The cooling unit 2 supplies cooling water for cooling the heat generated mainly by the welding gun 6A . The cooling unit 2 always operates while the power is on, and circulates cooling water between the welding gun 6A . A resin tube (not shown) is used for conveying the cooling water between the cooling unit 2 and the welding gun 6A . The power supply unit 3 converts the three-phase AC power supplied from the power receiving facility 400 (see FIG. 6) into a direct current, and further converts the converted direct current into a high frequency alternating current and outputs it. The support post 4 is erected in the vertical direction in the vicinity of the cooling unit 2 and supports the support arm 5 so as to be rotatable in the horizontal direction.

The support arm 5 includes a first arm 5A, a second arm 5B, and a rotation shaft 5C that rotatably connects the first arm 5A and the second arm 5B. The base end of the first arm 5A is It is supported on the upper end of the support post 4 so as to be rotatable in the horizontal direction. The gun shaft 8 has a long rod shape, and is disposed at the tip of the support arm 5 so as to be movable up and down in a direction perpendicular to the support arm 5. A welding gun 6 </ b > A and a handle 65 are disposed at the lower end of the gun shaft 8, a power feeding device 66 is disposed at the upper end, and a pressurizing device 67 is disposed immediately above the support arm 5. The gun shaft 8 provided with these various components is held in a state where it is pulled up with a constant tension by an elevating mechanism (not shown) provided at the tip of the second arm 5B. By this action of the lifting mechanism, the welding gun 6A can be stopped at an arbitrary position in the vertical direction.

The power feeding device 66 is a switch that incorporates two conductive metal plates (not shown) and is brought into contact with each other when supplied with compressed air. The pressurizing device 67 grips the gun shaft 8 by receiving supply of compressed air, and further presses the gun shaft 8 downward. The handle 65 has a ring shape and assists the manual rotation of the welding gun 6A . A push button type start switch 68 is disposed on the handle 65, and when the start switch 68 is pressed, a welding command is output to the power supply unit 3. The power supply unit 3 performs pressurization and current supply to the welding gun 6 </ b> A by receiving a welding command from the start switch 68. That is, upon receiving the welding command, the power supply unit 3 operates the pressurizing device 67 to pressurize the welding gun 6A in the direction toward the workpiece 500, and operates the power feeding device 66 to apply the welding gun 6A to the welding gun 6A . Supply power.

  The power feeding cable 7 is composed of two cables 7A and 7B, and connects between the welding transformer 10 and the gun shaft 8. The welding transformer 10 is equivalent to the welding transformer for resistance welding previously proposed by the inventors of the present invention in Japanese Patent Application Laid-Open Nos. 2012-210654 and 2013-179205, and is a high-speed and precise large-current welding control. Can follow. The welding transformer 10 will be described in detail later.

FIG. 2 is a side view showing a detailed configuration of the welding gun 6A . In the figure, a welding gun 6A includes a gun body 72, a sliding conductor 73, a fixed shaft portion 74 that rotatably supports the gun body 72 and the sliding conductor 73 in the horizontal direction, a fixed shaft portion 74, A first power feeding device 76 disposed between the gun main bodies 72 and a second power feeding device 77 disposed between the fixed shaft portion 74 and the sliding conductor 73 are provided. The gun body 72 has a U shape in which both the distal end portion 72A and the proximal end portion 72B are bent at right angles in the same direction. An inner electrode 85 </ b> A of the one-side electrode 85 is disposed at the distal end portion 72 </ b> A of the gun body 72. The sliding conductor 73 is disposed close to the second surface 72d opposite to the first surface 72c on the side where both end portions 72A and 72B of the gun body 72 are bent at a right angle, and the length of the second surface 72d of the gun body 72 is long. L is slidable in the direction (vertical direction in the figure), and the distal end portion 73A is bent at a right angle in the same direction as the distal end portion 72A of the gun body 72 and has a length that reaches the distal end of the gun body 72. It has a letter shape. An outer electrode 85 </ b> B of the one-side electrode 85 is disposed at the distal end portion 73 </ b> A of the sliding conductor 73. The one-side electrode 85 is provided across the tip portion 72A of the tip 72 of the gun body 72 of the welding gun 6A and the tip portion 73A of the sliding conductor 73, is electrically connected to the gun body 72, and is provided with an insulating ring 85C at the tip. The cylindrical inner electrode 85A and the outer electrode 85B, which is cylindrical and integrated with the sliding conductor 73, can be inserted in the axial direction in the axial direction.

  Between the gun main body 72 and the sliding conductor 73, a linear guide 80 for connecting them and guiding the sliding conductor 73 with respect to the gun main body 72 is disposed. The linear guide 80 includes a rail 80A and two connection pieces 80B that can slide on the rail 80A. The rail 80A is disposed on the sliding conductor 73 side, and the connection piece 80B is disposed on the gun body 72 side. Established. An insulating material is disposed on a portion of the connection piece 80B that contacts the rail 80A, and the rail 80A and the connection piece 80B are in a non-conductive state.

The fixed shaft portion 74 includes a first fixed shaft 741 made of a columnar conductive metal member and a cylindrical conductive metal member, and allows the first fixed shaft 741 to be inserted. One end of the first fixed shaft 741 A second fixed shaft 742 having an annular flange 742a extending in a direction perpendicular to the central axis direction, and a hole into which the second fixed shaft 742 can be inserted in the center. A disk-shaped first bearing support plate 743 formed. The first fixed shaft 741 has a length from the upper end of the annular flange 742a of the second fixed shaft 742 to the bottom surface of the first power feeding device 76, and the second fixed shaft 742 is first from the upper end of the annular flange 742a. 2 It has a length that reaches the bottom surface of the power feeding device 77. An insulating material 95 (see FIG. 5) is disposed between the first fixed shaft 741 and the second fixed shaft 742, and the first fixed shaft 741 and the second fixed shaft 742 are in a non-conductive state. The fixed shaft portion 74 is connected to the distal end portion of the gun shaft 8 so that the gun body 72 and the sliding conductor 73 can rotate freely around a central axis common to the first fixed shaft 741 and the second fixed shaft 742 as a rotation center. To support. The first fixed shaft 741 and the second fixed shaft 742 are connected to the secondary side of the welding transformer 10 through a coaxial cable (not shown) passing through the gun shaft 8 and the power supply cable 7 in order. In this case, the first fixed shaft 741 is connected to the negative electrode 24 on the secondary side of the welding transformer 10, and the second fixed shaft 742 is connected to the positive electrode 22 on the secondary side of the welding transformer 10.

  The first power supply device 76 electrically connects the first fixed shaft 741 and the gun body 72, and the second power supply device 77 electrically connects the second fixed shaft 742 and the sliding conductor 73. Is. An insulating material (not shown) is disposed between the first power feeding device 76 and the second power feeding device 77, and the first power feeding device 76 and the second power feeding device 77 are in a non-conductive state. Between the first power feeding device 76 and the gun main body 72, a cylinder 86 is disposed that urges the gun main body 72 downward by receiving supply of compressed air. The cylinder 86 prevents the gun body 72 from being pushed back by the pressurization when the inner electrode 85A supported by the gun body 72 is pressed against the workpiece 500 (see FIG. 6). In order to prevent the gun body 72 from retreating), a downward force is applied to the gun body 72. A piston (not shown) built in the cylinder 86 moves according to the amount of compressed air supplied to the cylinder 86. This piston is indirectly connected to the gun body 72. Since the first power feeding device 76 and the cylinder 86 are in a non-conductive state, the first power feeding device 76 and the gun body 72 are electrically connected by a metal jumper wire 82.

  A second bearing support plate 87 that is in a non-conducting state with the second power feeding device 77 and the sliding conductor 73 is disposed on the upper surface side of the second power feeding device 77. Between the second bearing support plate 87 and the first bearing support plate 743 of the fixed portion 74, a plurality of bearings 88 (only two are visible but two or more are present) are disposed. By these bearings 88, movable parts (that is, the gun main body 72, the sliding conductor 73, the first power feeding device 76, the second power feeding device 77, the linear guide 80, the one-side electrode 85, and the second bearing support plate 87 are provided. Can be rotated in the horizontal direction. Energization of the first fixed shaft 741 and the gun body 72 is performed via the jumper wire 82 described above.

  Although the first power supply device 76 and the second power supply device 77 have basically the same structure, although there are differences in size, the structure will be described by taking the first power supply device 76 as an example. FIG. 3 is a plan view showing the external configuration of the first power feeding device 76. In the figure, the first power feeding device 76 includes a first block body 761, a second block body 762, coil springs 763, 764, a bush 765, and pinching mechanisms 766, 767. In this embodiment, among these components, at least the first and second block bodies 761 and 762 and the bush 765 are made of a metal material having excellent conductivity such as copper. In this embodiment, metal coil springs 763 and 764 are used, but non-metallic elastic members such as rubber can also be used.

The first block body 761 is made of a conductive metal member, has a three-dimensional shape that is concave in plan view, and the recessed portion is a semicircular groove 7611. Further, in the first block member 761, the through holes 7612,7613 in both sides of the semi-circular groove 7611 is formed. These through holes 7612 and 7613 are formed in the short direction of the first block body 761 (perpendicular to the direction of the center of the semicircular groove 7611) at a certain distance from the center of the semicircular groove 7611. Is done. Further, both of these through holes 7612 and 7613 have a different diameter structure in which the diameter on the open end side of the semicircular groove 7611 is increased. One end portion of the coil spring 763 is inserted into the large diameter portion (referred to as “large diameter portion”) 7612 a of the through hole 7612, and the large diameter portion (referred to as “large diameter portion”) 7613 a of the through hole 7613 is inserted into the 7613 a. The one end portion of the coil spring 764 is inserted.

On the other hand, the second block body 762 is made of substantially the same shape and the same member as the first block body 761 , and the surface side on which the semicircular groove 7621 is formed is the surface on which the semicircular groove 7611 of the first block body 761 is formed. It is arranged to face the side. In the second block body 762, through holes 7631 and 7632 are formed on both sides of the semicircular groove 7621. These through holes 7631 and 7632 are formed in the short direction of the second block body 762 (perpendicular to the direction of the center of the semicircular groove 7621) at a certain distance from the center of the semicircular groove 7621. Is done. Further, both of these through holes 7631 and 7632 have a different diameter structure in which the diameter on the open end side of the semicircular groove 7621 is increased. The other end portion of the coil spring 763 is inserted into a large diameter portion (referred to as “large diameter portion”) 7631 a of the through hole 7631, and a large diameter portion (referred to as “large diameter portion”) 7632 a of the through hole 7632 The other end portion of the coil spring 764 is inserted.

  As described above, the coil spring 763 is inserted between the large diameter portion 7612a of the through hole 7612 of the first block body 761 and the large diameter portion 7631a of the through hole 7631 of the second block body 762, and the coil spring 764 is The first block body 761 is inserted between the large diameter portion 7613 a of the through hole 7613 of the first block body 761 and the large diameter portion 7632 a of the through hole 7632 of the second block body 762. In this case, since the coil springs 763 and 764 are disposed in a compressed state between the first block body 761 and the second block body 762, the first block body 761 and the second block body 762 are always moved by the restoring force. Acts to pull apart.

  The first and second block bodies 761 and 762 are connected to each other by the pinching mechanisms 766 and 767 in a state where the surfaces on which the semicircular grooves 7611 and 7621 are formed face each other. The pinching mechanism 766 includes a cylindrical rod-shaped rod 7661 having an outer diameter that can be inserted into the coil spring 763 by being threaded at the tip, and a nut 7762 that is screwed to the screw that is cut at the tip of the rod 7661. A washer 7663 inserted between the nut 7762 and the open end of the through hole 7612 of the first block body 761 and a cylinder 7664 with a built-in piston are provided. The cylinder 7664 is configured to move a built-in piston (not shown) when supplied with compressed air. Since the other end of the rod 7661 is connected to the piston in the cylinder 7664, the compressed air is supplied to the cylinder 7664 and the piston moves, so that the rod 7661 is drawn toward the cylinder 7664. When the rod 7661 is pulled toward the cylinder 7664 side, one end portion in the longitudinal direction of the first block body 761 connected to the rod 7661 (that is, the right end portion in the drawing) is pulled toward the second block body 762 side.

  The pinching mechanism 767 also has the same structure as the pinching mechanism 766 and is cut at the tip of the rod 7671 having a cylindrical rod shape having an outer diameter that can be inserted through the coil spring 764 with a screw cut at the tip. A nut 7672 that is screwed into the screw, a washer 7673 inserted between the nut 7672 and the open end of the through hole 7613 of the first block body 761, and a cylinder 7647 with a built-in piston. A cylinder (not shown) is movable in the cylinder 7673 by receiving supply of compressed air. Similarly to the cylinder 7664 described above, the other end of the rod 7671 is connected to the built-in piston. Therefore, when the compressed air is supplied to the cylinder 7664 and the piston is moved, the rod 7671 is drawn toward the cylinder 7673 side. . When the rod 7671 is drawn toward the cylinder 7673 side, the other end portion in the longitudinal direction of the first block body 761 connected to the rod 7671 (that is, the left end portion in the drawing) is drawn toward the second block body 762 side.

  Since compressed air is supplied to the cylinders 7664 and 7664 of the clamping mechanisms 766 and 767 at the same time, the first block body 761 is drawn by the cylinder 7664 of the clamping mechanism 766, and the clamping mechanism 767. The first block body 761 is drawn simultaneously by the cylinder 7684. That is, the first block body 761 is drawn toward the second block body 762 while the first block body 761 and the second block body 762 are kept parallel. In the present embodiment, the first block body 761 is drawn toward the second block body 762, but the first block body 761 and the second block body 762 may be drawn toward each other. .

  4A and 4B show the bush 765 of the first power feeding device 76, where FIG. 4A is an external view viewed from the axial direction, and FIG. 4B is an external view viewed from a direction perpendicular to the axial direction. As shown in the figure, the bush 765 is made of a cylindrical conductive metal member, and grooves 765a and 765b having a length from one opening end to the other opening end are provided in the circumferential direction on the outer peripheral surface and the inner peripheral surface. 8 are formed along. The groove 765a formed on the outer peripheral surface of the bush 765 has a substantially W-shaped cross-sectional shape, and the groove 765b formed on the inner peripheral surface has a substantially V-shaped cross-sectional shape. The outer diameter of the bushing 765 is contracted when the first and second block bodies 761 and 762 are sandwiched between the semicircular groove 7611 of the first block body 761 and the semicircular groove of the second block body 762. It is formed so as to be larger than the diameter of a circle obtained when 7621 are combined. That is, the bush 765 is formed so as to partially fit into the semicircular groove 7611 of the first block body 761 and the semicircular groove 7621 of the second block body 762.

  Here, the first block body 761 and the second block body 762 are called fixed portions, and the first fixed shaft 741 fitted into the bush 765 is called a movable portion. When a current is supplied to the one-side electrode 85 through the fixed portion and the movable portion, the clamping mechanisms 766 and 767 are simultaneously operated to clamp the bush 765. By simultaneously operating the clamping mechanisms 766 and 767, the bush 765 is evenly pressurized over the entire circumference of the outer peripheral surface. Thereby, the inner peripheral surface of the bush 765 is brought into close contact with the surface of the first fixed shaft 741 over the entire periphery, and the fixed portion and the movable portion are brought into conduction. In this case, the semicircular groove 761 is formed so that the diameter of the circle obtained when the semicircular groove 7611 of the first block body 761 and the semicircular groove 7621 of the second block body 762 are combined is smaller than the outer diameter of the bush 765. Since the shapes of 7611 and 7621 and the bush 765 are determined, the bush 76 can be easily contracted, and the inner peripheral surface of the bush 76 can be firmly adhered to the surface of the first fixed shaft 741 without a gap. . Further, since the cross-sectional shape of the groove 765a of the bush 765 is substantially W-shaped on the outer peripheral surface side and substantially V-shaped on the inner peripheral surface side, the bush 765 can be easily contracted, and the first and second blocks Reduction of the clamping pressure by the bodies 761 and 762 can be achieved. That is, the bush 765 can be brought into close contact with the first fixed shaft 741 with a small clamping pressure. By adopting the first power feeding device 76 adopting such a structure, a large current is stably supplied between the first block body 761 and the second block body 762 serving as fixed portions and the first fixed shaft 741 serving as a movable portion. It is possible to flow.

  The bush 765 has eight grooves 765a and 765b formed on the outer peripheral surface and the inner peripheral surface, respectively, but the surface on which the groove is formed is either the outer peripheral surface or the inner peripheral surface. Also good. The number of grooves may be 1, but as the number of grooves is increased, the first block body 761 and the second block body 762 which are fixed portions, and the first fixed shaft 741 which is a movable portion, It can be said that the larger one is more effective because the adhesion of the is improved. Incidentally, in an actual resistance welding apparatus, 16 are formed.

  Further, a conductive filler (carbon, carbon dioxide) is formed between the surface of each of the semicircular groove 7611 of the first block body 761 and the semicircular groove 7621 of the second block body 762 and the outer peripheral surface of the bush 765 and on the inner peripheral surface of the bush 765. You may make it apply | coat the grease to which the metal powder, the metal oxide, etc.) were added. By applying this grease, the unevenness of the contact surface is filled, and the contact surface can be flattened to maintain a stable contact surface. Further stabilization of energization can be achieved, and wear due to sliding of the contact surface can be prevented.

  FIG. 5 is a diagram illustrating longitudinal sections of the first and second power feeding devices 76 and 77 and the first and second fixed shafts 741 and 742 of the resistance welding apparatus 1A according to the first embodiment and current paths during welding. is there. In addition, in the same figure, the code | symbol 771 is attached | subjected to the 1st block body which comprises the 2nd electric power feeder 77, the code | symbol 772 is provided to the 2nd block body, and the code | symbol 775 is attached to the bush.

The welding current Ie that has flowed into the second fixed shaft 742 passes through the bush 775 of the second power feeding device 77 and the first and second block bodies 771 and 772 of the second power feeding device 77 and passes through the sliding conductor 73 (in FIG. 5). (Not shown). The welding current Ie flowing into the sliding conductor 73 sequentially passes through the outer electrode 85B of the one-side electrode 85, the workpiece 500 (see FIG. 1), the inner electrode 85A of the one-side electrode 85, the gun body 72, and the jumper wire 82. It flows into the first and second block bodies 761 and 762 of the first power feeding device 76. Thereafter, it flows into the first fixed shaft 741 through the bush 765. Thus, the current path in the welding gun 6A is as follows: the second fixed shaft 742 → the second power feeding device 77 → the sliding conductor 73 → the outer electrode 85B of the one-side electrode 85 → the workpiece 500 → the inner electrode 85A of the one-side electrode 85. → Gun body 72 → jumper wire 82 → first power feeder 76 → first fixed shaft 741

Returning to FIG. 1, the table 9 has a substantially square flat plate shape on which the workpiece 500 is placed. The workpiece 500 is a plate set formed by superposing at least two steel plates, for example. In addition, in the to-be-welded object 500, there exist what a protective sheet was affixed on the back surface (for example, the back surface of the two steel plates piled up from the one side electrode), and the thing to which the coating was given. The welding condition setter 11 sets welding conditions such as the material and thickness of the workpiece 500. The one-side electrode 85 is attached to the tip portion of the welding gun 6A . As shown in FIG. 2, the one-side electrode 85 is electrically connected to the gun body 72, and is integrated with a cylindrical inner electrode 85 </ b> A having an insulating ring 85 </ b> C disposed at the tip and the sliding conductor 73, and is axially inner. It is comprised with the cylindrical outer side electrode 85B which the both ends which can insert electrode 85A open.

Next, the power supply unit 3 will be described.
FIG. 6 is a diagram showing a schematic configuration of the resistance welding apparatus 1A. In the figure, the power supply unit 3 includes a rectifier 300, a smoothing capacitor 301, a welding control circuit 302, and an inverter circuit 303. The rectifier 300 employs a single-phase full-wave rectification type, and rectifies three-phase alternating current from the power receiving facility 400 and converts it into direct current. The welding control circuit 302 controls the magnitude and energization time of the welding current Ie corresponding to the welding conditions set by the welding condition setting unit 11. For example, a microcomputer is used for the welding control circuit 302. The microcomputer holds a program for welding control and operates according to the program. The welding control circuit 302 detects the welding command Sw from the start switch 68 provided in the welding gun 6A, and thereby the timing according to the material and thickness of the workpiece 500 set by the welding condition setting unit 11. A signal Si is generated and output to the inverter circuit 303. For example, the welding control circuit 302 generates the timing signal Si so that the welding current Ie becomes a maximum value within 15 milliseconds from the start of energization and the welding is completed within an energization time of 50 milliseconds or less.

  The inverter circuit 303 includes an inverter control unit 3031, four switches S <b> 1 to S <b> 4 using, for example, an IGBT (Insulated Gate Bipolar Transistor), and a current sensor 3032 using, for example, a CT (Current Transformer). The inverter control unit 3031 controls on / off of each of the switches S1 to S4 based on the timing signal Si generated by the welding control circuit 302 and the primary current If detected by the current sensor 3032 to generate high-frequency alternating current. To do. The magnitude of the high-frequency alternating current generated by the inverter control unit 3031 varies depending on the on / off duty of each of the switches S1 to S4. By changing the on / off duty of each of the switches S1 to S4, the width of W of the switching waveform changes as shown in FIG.

FIG. 7 is a diagram illustrating a control pulse for controlling a current supplied to the primary side of the welding transformer 10, a primary current If, and a rectified welding current Ie. In the figure, a pulse (switching pulse) having a width W controlled by the inverter circuit 303 is repeated a certain number of times within a certain time H, in this case, a total of 10 times of a positive direction pulse and a negative direction pulse. It is supplied to the primary coil 12. Thereby, the primary current If as shown in FIG. 7B flows through the primary coil 12 of the welding transformer 10. When the primary current If flows through the primary coil 12 of the welding transformer 10, the secondary current generated on the secondary side of the welding transformer 10 is full-wave rectified by the rectifying elements 18 and 20, and FIG. a welding current Ie as shown in and flowing through the welding gun 6A.

  The magnitude of the welding current Ie can be adjusted by increasing or decreasing the pulse width W shown in FIG. In addition, the welding time can be adjusted by increasing or decreasing the number of times of pulse supply. That is, when the pulse repetition frequency is increased, the welding time can be finely adjusted. Further, if the power supplied to the primary coil 12 of the welding transformer 10 is increased, a larger welding current Ie can be extracted from the secondary coil 14.

The primary coil 12 of the welding transformer 10 is connected to the output side of the inverter circuit 303 of the power supply unit 3. FIG. 8 is a diagram showing the connection between the welding transformer 10 and the welding gun 6A . In the figure, the primary coil 12 of the welding transformer 10 is connected to the output terminal of the inverter circuit 303 of the power supply unit 3. By outputting high-frequency alternating current from the inverter circuit 303, a primary current flows through the primary coil 12 of the welding transformer 10. The secondary coil 15 of the welding transformer 10 does not need to consider the polarity itself, but for the sake of convenience, the secondary coil 15 of the welding transformer 10 has a positive coil 14 and a negative coil 16 connected in series. I will call it. The anode (positive electrode) of the first rectifying element 18 is connected to one end of the positive side coil 14, and the anode (positive electrode) of the second rectifying element 20 is connected to one end of the negative side coil 16. The cathode (negative electrode) of the first rectifying element 18 and the cathode (negative electrode) of the second rectifying element 20 are commonly connected to the plus electrode 22, and the other end of the positive side coil 14 and the other end of the negative side coil 16 are minus electrodes 24. Commonly connected to

A welding gun 6 </ b> A is connected to the plus electrode 22 and the minus electrode 24 via a coaxial cable (not shown) passing through the power feeding cable 7 and the gun shaft 8. That is, the second fixed shaft 742 of the welding gun 6A is connected to the positive electrode 22 on the secondary side of the welding transformer 10, and the first fixed shaft 741 of the welding gun 6A is connected to the negative electrode 24 on the secondary side of the welding transformer 10. Is done. The second fixed shaft 742 is connected to the sliding conductor 73 via the second power feeding device 77, and the first fixed shaft 741 is connected to the gun body 72 via the first power feeding device 76. Further, since the outer electrode 85B of the one-side electrode 85 is connected to the tip portion of the sliding conductor 73 and the inner electrode 85A of the one-side electrode 85 is connected to the tip portion of the gun body 72, the secondary side of the welding transformer 10 is connected. The positive electrode 22 is connected to the outer electrode 85B of the one-side electrode 85, and the secondary negative electrode 24 of the welding transformer 10 is connected to the outer electrode 85A of the one-side electrode 85. Due to such a connection relationship, the welding current supplied to the one-side electrode 85 flows in a direction from the outer electrode 85B toward the inner electrode 85A.

  In the resistance welding apparatus 1A according to the first embodiment, the plus electrode 22 of the welding transformer 10 is connected to the outer electrode 85B of the one-side electrode 85, and the minus electrode 24 of the welding transformer 10 is connected to the inner electrode 85A of the one-side electrode 85. Thus, although the welding current flows in the direction from the outer electrode 85B toward the inner electrode 85A, it may be reversed. That is, the plus electrode 22 of the welding transformer 10 may be connected to the inner electrode 85A of the one-side electrode 85, and the minus electrode 24 of the welding transformer 10 may be connected to the outer electrode 85B of the one-side electrode 85.

FIG. 9 is a diagram illustrating a circuit operation when a forward current flows through the first rectifying element 18. FIG. 10 is a diagram illustrating a circuit operation when a forward current flows through the second rectifying element 20. 9 and 10, an equivalent inductance component that causes a problem in circuit operation is added to the circuit shown in FIG. That is, the inductance of the positive conductor 30 that connects the positive coil 14 and the first rectifier 18, the inductance of the negative conductor 32 that connects the negative coil 16 and the second rectifier 20, and the power supply cable 7 are included. It is considered that the inductance of the conductor in the welding gun 6A affects the performance of the resistance welding apparatus.

If a large amount of heat generated in the welding gun 6A including the welding transformer 10 and the power supply cable 7 can be suppressed, energy saving of the resistance welding apparatus can be achieved, and a large power saving effect can be expected. This can be realized if it can be controlled so that a larger current than in the prior art is supplied to the welding gun 6A for a short time. On the other hand, in order to supply the optimum welding current for the material or structure to be welded, it is necessary to control the welding current supply time with extremely high accuracy. This can be realized by connecting the inverter circuit 303 to the primary side of the welding transformer 10 for supplying the welding current, and controlling the magnitude of the welding current and the supply time by PWM control.

Here, the conventional resistance welding apparatus, for example, is to supply the welding current of 200m sec ~700m sec 10,000 amperes and try to welding current 20,000 amperes twice, welding gun 6A The power loss that is consumed as thermal energy in other places becomes extremely large, which is a practical problem. Therefore, even if the welding current is doubled, if the welding time is reduced to 1/10, the power consumption can be reduced to 1/5, which is not a problem in practice.

  On the other hand, the control pulse of the inverter circuit for supplying the welding current has conventionally used a repetition frequency of about 1 kHz. However, in order to supply a large current for a short time, a control pulse with higher resolution is required. become. In the inverter circuit 303 of the resistance welding apparatus 1A according to the present embodiment, a pulse having a repetition frequency of about 5 kHz to 50 kHz is output. When a pulse having a repetition frequency as high as several times to several tens of times of the prior art is supplied to a conventional welding transformer, a predetermined welding current cannot be obtained, but the welding transformer 10 used in the resistance welding apparatus 1A according to the present embodiment is And, it has a structure capable of obtaining a predetermined welding current even with a pulse having a repetition frequency as high as several times to several tens of times the conventional one. Hereinafter, the structure of the welding transformer 10 used in the resistance welding apparatus 1A according to the present embodiment will be described.

  FIG. 11 is a perspective view showing an appearance of the welding transformer 10 of the resistance welding apparatus 1A according to the first embodiment. FIG. 12 is a perspective view showing an assembled state of the welding transformer 10. 11 and 12, the welding transformer 10 is divided into a plurality of portions, an annular magnetic core 25 constituted by a parallel portion 25a and U-shaped curved portions 25b at both ends, and a parallel portion 25a of the annular magnetic core 25. The primary coil 12 that is divided and wound with a gap 12a, and the primary coil 12 are wound around the parallel portion 25a of the annular magnetic core 25 so as to be sandwiched one by one in each gap 12a provided in the primary coil 12. The secondary coil 15 in which a plurality of positive side coils 14 and a plurality of negative side coils 16 are alternately arranged, and the plurality of positive side coils 14 are all connected in parallel or all or part of them are connected in series, The negative side coils 16 are all connected in parallel or all or part of them are connected in series, and the positive side coils 16 and the negative side coils 16 are connected in series so that the connected positive side coils 14 and the negative side coils 16 are connected in series. Connection board having a conductor group electrically connecting the terminals of the cable 14 and the negative side coil 16 and supporting and fixing all the positive side coil 14 and the negative side coil 16 on one surface by the conductor group. 62, and one terminal of each of the plurality of positive side coils 14 is electrically connected to the first connecting pole plate 44 extending in the direction parallel to the parallel portion 25a of the annular magnetic core 25 on the other surface of the connection substrate 62. One terminal of the plurality of negative side coils 16 is electrically connected to the second connecting electrode plate 46 extending in the direction parallel to the parallel part 25a of the annular magnetic core 25 on the other surface side of the connection substrate 62, and is connected to the positive side. The other terminal of the coil 14 and the other terminal of the negative coil 16 are both connected to the third connecting pole plate 48 extending in the direction parallel to the parallel portion 25 a of the annular magnetic core 25 on the other surface side of the connection substrate 62. The first conductor plate 44 is electrically connected to the positive conductor 30, The negative electrode conductor 32 is connected to the two-connection electrode plate 46, and the positive electrode conductor 30 and the negative electrode conductor 32 extend on the other surface side of the connection board 62 in a direction perpendicular to the other surface. A pair of conductor plates stacked via an insulating layer 31 disposed between the positive electrode conductor 30 and the first electrode plate 34 to which the positive electrode 22 (see FIGS. 6 and 8) is connected. Thus, the first rectifying element 18 in which the anode (positive electrode) is in contact with the positive conductor 30 and the cathode (negative electrode) is in contact with the first electrode plate 34, and the second electrode in which the negative conductor 32 and the negative electrode 24 are connected. The second rectifying element 20 sandwiched between the plate 36, the anode (positive electrode) is in contact with the negative conductor 32, and the cathode (negative electrode) is in contact with the second electrode plate 36, the first electrode plate 34, and the second electrode A third electrode plate 38 that supports the plate 36 and electrically connects both is connected to the third electrode plate 38. The positive electrode 22 and the negative electrode 24 connected to the third coupling electrode plate 48 are provided.

  Since the welding transformer 10 has such a structure, a predetermined welding current can be obtained even with a pulse having a high frequency (about 5 kHz to 50 kHz) from the inverter circuit 303.

  By the way, a full-wave rectification type secondary circuit using two rectifying elements 18 and 20 as shown in FIG. 6 has a smaller number of rectifying elements than a circuit using a bridge, and can be reduced in size and power loss. Since it is small, it is known that it is suitable for resistance welding equipment. However, in this secondary circuit, when the voltage induced in the secondary coil 15 is reversed due to the polarity reversal of the current flowing through the primary coil 12, the load current supplied through one rectifier element is A commutation that changes the flow occurs on the rectifying element side.

  When the welding current becomes large, the current energy accumulated in the inductance of each part of the circuit becomes very large. The commutation time during which this current energy moves from one rectifying element to the other rectifying element becomes longer as the inductance of each part of the secondary coil 15 shown in FIGS. If the commutation of the secondary circuit is not completed during the time M from the start of the fall of the current of the primary coil 12 shown in FIG. 7 to the end of the rise of the current having the opposite polarity, the rise of the secondary current is delayed. As shown by the broken line 7, the planned welding current cannot be obtained.

  In the welding transformer 10 used in the resistance welding apparatus 1A according to the first embodiment, the positive conductor 30 and the negative conductor 32 are in close contact with each other through the insulating layer 31, and the positive coil 14 of the secondary coil 15 is Since these coils are arranged so that the primary coil 12 is sandwiched between the negative side coils 16, the inductance at the time of commutation of the secondary side circuit of the welding transformer 10 is reduced, and the commutation in the secondary side circuit is reduced. Flow time is shortened. Therefore, by using the welding transformer 10, higher frequency inverter control is possible.

  Moreover, the welding transformer 10 can make the heat distribution of the whole welding transformer uniform by the arrangement of the primary coil 12 and the secondary coil 15.

  Further, since the welding transformer 10 divides and winds the positive coil 14 and the negative coil 16 of the primary coil 12 and the secondary coil 15, respectively, the primary coil 12 and the secondary coil 15 are coupled to each other. The coupling between the secondary coil 12 and the secondary coil 15 can be strengthened, and magnetic saturation due to a large secondary current can be prevented.

  In addition, since the relationship between the positive coil 14 and the negative coil 16 of the primary coil 12 and the secondary coil 15 is uniform everywhere, the welding transformer 10 can be disposed in close contact with each other and welded. The transformer 10 can be miniaturized.

  As described above, according to the resistance welding apparatus 1A according to the first embodiment, the first power feeding device 76 for energizing the first fixed shaft 741 and the gun body 72, the second fixed shaft 742, and the sliding conductor. 73, the second power feeding device 77 for energizing between the first fixed shaft 741 and the gun body 72, and the power feeding cable connecting the second fixed shaft 742 and the sliding conductor 73 to each other. It can be omitted, and a large current can flow stably between them. As a result, the current from the welding transformer 10 capable of supplying a large current in a short time can be efficiently passed through the one-side electrode 85, and the advantage of the one-side electrode 85 (that is, the cover having a protective sheet attached on one side). In welding of welded materials, it is difficult to generate indentations or heat-induced burns or distortions on the back surface, and in welding of one-side-coated workpieces, it is difficult to generate burns or thermal discoloration). . Further, since a large current can be flowed in a short time, power saving can be achieved.

Further, the welding gun 6A capable of moving in the horizontal direction has an opening on the upper surface, and the welded gun 6A has an extension extending inward from the periphery of the opening. When welding is performed directly under the extended portion of the object, the extended portion can be welded without becoming an obstacle.

  In the resistance welding apparatus 1A according to the first embodiment, the power feeding device 66 may be replaced with the power feeding device 76 (or the power feeding device 77).

(Second Embodiment)
Next, a resistance welding apparatus according to the second embodiment of the present invention will be described.
FIG. 13 is a side view showing an external configuration of a resistance welding apparatus 1B according to the second embodiment. In addition, the same code | symbol is attached | subjected about the component and member which are common in FIG. 1 mentioned above in the figure, and the description is abbreviate | omitted.

A resistance welding apparatus 1B according to the second embodiment has a welding gun 6B that is integrated with a welding transformer. That is, in the resistance welding apparatus 1A according to the first embodiment described above, the welding gun 6A and the welding transformer 10 are connected by a coaxial cable (not shown) passing through the power supply cable 7 and the gun shaft 8, The resistance welding apparatus 1B according to the second embodiment has a welding gun 6B in which a welding transformer is directly connected, thereby omitting a power feeding cable. By omitting the power feeding cable, the current from the welding transformer that can supply a large current in a short time can be more efficiently passed to the one-side electrode 85.

  In FIG. 13, the resistance welding apparatus 1B according to the second embodiment includes a casing 90, a control / power supply unit 91, a cooling unit 92, a welding gun 6B, a gun up / down moving mechanism 93, and a gun turning mechanism 94. , A table 96 and a table moving mechanism 97. As shown in the figure, the housing 90 has a substantially U-shape when viewed from the side. A gun up-and-down moving mechanism 93 is disposed at the upper center of the inside, and the welding gun 6B is located near the upper opening. In addition, a gun turning mechanism 94 is provided. The gun up-and-down moving mechanism 93 operates according to an instruction from the control / power supply unit 91, and moves the welding gun 6B up and down in the standing direction (substantially vertical direction) of the housing 90 by the driving force of the motor 93a. The gun turning mechanism 94 operates in accordance with an instruction from the control / power supply unit 91 to rotate the welding gun 6B in a direction perpendicular to the standing direction of the housing 90 (substantially horizontal direction). The gun turning mechanism 94 rotates the welding gun 6B by rotating the belt 94b hung on the second bearing support plate 87 (see FIG. 14) using the power of the motor 94a. The table 96 mounts the workpiece 500. The table moving mechanism 97 operates in accordance with an instruction from the control / power supply unit 91 and moves the table 96 on the XY plane. The control / power supply unit 91 controls the table moving mechanism 97 so that the welding location of the workpiece 500 is positioned directly below the one-side electrode 85.

  FIG. 14 is a side view showing a detailed configuration of the welding gun 6B of the resistance welding apparatus 1B according to the second embodiment. In the figure, parts and members common to the welding gun 6A of FIG. 2 described above are denoted by the same reference numerals and description thereof is omitted. In the figure, a welding gun 6B includes a gun body 72, a sliding conductor 73, a fixed shaft portion 74B that supports the gun body 72 and the sliding conductor 73 so as to be rotatable in the horizontal direction, and a fixed shaft portion 74B. A first power feeding device 76 disposed between the gun main bodies 72 and a second power feeding device 77 disposed between the fixed shaft portion 74 </ b> B and the sliding conductor 73 are provided. The gun main body 72, the sliding conductor 73, the gun main body 72, the first power feeding device 76, and the second power feeding device 77 are the same as those of the resistance welding apparatus 1A according to the first embodiment described above. The fixed shaft portion 74B different from the resistance welding apparatus 1A according to the first embodiment will be described.

  The fixed shaft portion 74B is composed of a cylindrical conductive metal member, one end of which is directly connected to the negative electrode 24 of the welding transformer 10B, and a cylindrical conductive metal member. The first fixed shaft 741B can be inserted while maintaining a non-energized state with 741B, and the opening end side located on the same side as one end of the first fixed shaft 741B is in the direction of the central axis Ax (see FIG. 13). And a second fixed shaft 742B that is directly connected to the plus electrode 22 of the welding transformer 10B. The fixed shaft portion 74B supports the gun body 72 and the sliding conductor 73 so as to be rotatable about a central axis common to the first fixed shaft 741B and the second fixed shaft 742B.

  Here, the welding transformer 10B used in the resistance welding apparatus 1B according to the second embodiment basically has the same structure as the welding transformer 10 used in the resistance welding apparatus 1A according to the first embodiment. There is a difference in the mounting structure of the plus electrode 22 and the minus electrode 24. FIG. 15 is a perspective view showing an appearance of a welding transformer 10B used in the resistance welding apparatus 1B according to the second embodiment. As shown in the figure, the electrode mounting surface of the third electrode plate 38 and the electrode mounting surface of the third connecting electrode plate 48 are at the same position, and the positive electrode 22 is placed on the electrode mounting surface of the third electrode plate 38. Is attached, and the negative electrode 24 is attached to the electrode attachment surface of the third connecting electrode plate 48. Both the plus electrode 22 and the minus electrode 24 are formed in a rectangular block shape having the same thickness.

  On the other hand, as shown in FIG. 14, the end of the first fixed shaft 741B on the welding transformer 10B side is bent in a direction perpendicular to the central axis direction of the first fixed shaft 741B (this portion is “extended”). A gap is formed between the flange portion 742Ba of the second fixed shaft 742B and the plus electrode 22 of the welding transformer 10 by the thickness of the extending portion 741Ba. Therefore, the spacer 750 is interposed between the flange 742Ba of the second fixed shaft 742B and the plus electrode 22 of the welding transformer 10B. Of course, the spacer 750 is made of a conductive metal member such as copper. Via the spacer 750, the flange 742Ba of the second fixed shaft 742B and the plus electrode 22 of the welding transformer 10B are connected.

  Thus, according to the resistance welding apparatus 1B according to the second embodiment, since the welding transformer 10B is directly connected to the fixed shaft portion 74B, a larger amount of current can flow than the resistance welding apparatus 1A according to the first embodiment. This enables a large current to flow stably between the welding transformer 10 and the fixed shaft portion 74B. Of course, it has the 1st electric power feeder 76 which energizes between the 1st fixed shaft 741B and the gun main body 72, and the 2nd electric power feeder 77 which energizes between the 2nd fixed shaft 742B and the sliding conductor 73. Therefore, the power supply cable can be omitted between the first fixed shaft 741B and the gun body 72, and between the second fixed shaft 742B and the sliding conductor 73, and the resistance according to the first embodiment as a whole. It becomes possible to flow more current than the welding apparatus 1A. Further, since a large current can be flowed in a short time, power saving can be achieved.

  In addition, the welding gun 6B that enables movement in the horizontal direction has an opening on the top surface, and the welded gun 6B has an extension extending inward from the periphery of the opening. When welding is performed directly under the extended portion of the object, the extended portion can be welded without becoming an obstacle.

  In the resistance welding apparatus 1B according to the second embodiment, the power feeding device 66 may be replaced with the power feeding device 76 (or the power feeding device 77).

  In addition, the resistance welding apparatus 1B according to the second embodiment is provided with one set of the welding gun 6B, the gun up-and-down moving mechanism 93, and the gun turning mechanism 94, but it is of course possible to provide two or more sets. When two or more sets are provided, for example, they are arranged in parallel in a direction perpendicular to the standing direction of the apparatus body (that is, in the horizontal direction). If two or more sets of the welding gun 6B, the gun up-and-down moving mechanism 93, and the gun turning mechanism 94 are provided, and the table 96 is interlocked with each group, it becomes possible to perform welding in a flow work and productivity. Can be further improved.

  Although the invention has been described with reference to particular 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.

  The present invention has an effect of allowing a large current to flow stably between a fixed portion and a movable portion in a rotating mechanism portion for rotating the welding gun while rotating the welding gun around the axis. Can be applied.

1A, 1B Resistance welding device 2,92 Cooling unit 3 Power supply unit 4 Support post 5 Support arm 5A First arm 5B Second arm 5C Rotating shaft 6A, 6B Welding gun 7 Feeding cable 8 Gun shaft 9, 96 Table 10, 10B Welding transformer 11 Welding condition setting device 12 Primary coil of welding transformer 14 Positive side coil of secondary coil of welding transformer 15 Secondary coil of welding transformer 16 Negative side coil of secondary coil of welding transformer 18 First rectifying element 20 First 2 Rectifying element 22 Positive electrode of welding transformer 24 Negative electrode of welding transformer 65 Handle 66 Power feeding device 67 Pressurizing device 68 Start switch 72 Gun body 73 Sliding conductors 74 and 74B Fixed shaft portion 76 First power feeding device 77 Second power feeding Equipment 80 Linear motion guide 82 Jumper wire 85 One side electrode 5A Inner electrode 85B Outer electrode 85C Insulating ring 88 Bearing 90 Housing 91 Control / power supply unit 93 Gun vertical moving mechanism 93a, 94a Motor 94 Gun turning mechanism 94b Belt 97 Table moving mechanism 302 Welding control circuit 303 Inverter circuit 3031 Inverter controller 400 Power receiving equipment 500 Workpieces 741, 741B First fixed shaft 742 Second fixed shaft 741Ba Extension portion 742B Second fixed shaft 742Ba Hook 750 Spacer 761 First block body 762 Second block body 763, 764 Coil spring 765 Bush 765a , 765b bushing groove 766, 767 clamping mechanism
7611, 7621 semi-circular groove

Claims (2)

A primary core that is divided and wound into a plurality of portions around the annular magnetic core 25 composed of a parallel portion 25a and U-shaped curved portions 25b at both ends, and the parallel portion 25a of the annular magnetic core 25 with a gap 12a. A plurality of positive side coils are wound around the parallel part 25a of the annular magnetic core 25 together with the coil 12 and the primary coil 12 so as to be sandwiched one by one in the gaps 12a provided in the primary coil 12. 14 and a plurality of negative coils 16 are alternately arranged, and the plurality of positive coils 14 are all connected in parallel or all or a part thereof are connected in series, and the plurality of negative coils 16 are all connected in parallel, or all or part of them are connected in series, and the plurality of connected positive coils 14 and the plurality of negative coils 16 are connected in series to each other. A conductor group that electrically connects the terminals of the side coil 14 and the negative side coil 16, and the positive side coil 14 and the negative side coil 16 are placed on one surface by the conductor group. A connection board 62 for supporting and fixing is provided, and one terminal of the plurality of positive side coils 14 extends in a direction parallel to the parallel portion 25a of the annular magnetic core 25 on the other surface of the connection board 62. One terminal of the plurality of negative coils 16 extends in a direction parallel to the parallel portion 25a of the annular magnetic core 25 on the other surface side of the connection board 62. The other end of the positive side coil 14 and the negative side coil 16 is electrically connected to the second connecting electrode plate 46, and the other side of the connection substrate 62 is connected to the parallel portion 25 a of the annular magnetic core 25. Electricity is applied to the third connecting plate 48 extending in the parallel direction. A positive conductor 30 is connected to the first connecting electrode plate 44, a negative conductor 32 is connected to the second connecting electrode plate 46, and the positive conductor 30 and the negative conductor 32 are connected. Is a pair of conductor plates that are superimposed on each other on the other surface side of the connection substrate 62 via an insulating layer 31 disposed on a boundary surface extending in a direction away from the other surface. A rectifying element 18 sandwiched between a side conductor 30 and a first electrode plate 34 and having a negative electrode in contact with the positive electrode conductor 30 and a positive electrode in contact with the first electrode plate 34, the negative conductor 32 and a second electrode A rectifying element 20 sandwiched between plates 36 and having a negative electrode in contact with the negative conductor 32 and a positive electrode in contact with the second electrode plate 36, and the first electrode plate 34 and the second electrode plate 36 are supported. A third electrode plate 38 electrically connecting the two and a positive electrode 2 connected to the third electrode plate 38 2 and a negative electrode 24 connected to the third connecting electrode plate 48, a welding transformer 10 comprising:
A U-shaped gun body 72 in which both the distal end portion 72A and the proximal end portion 72B are bent at a right angle in the same direction, and a first surface on the opposite side to the first surface on the side where both end portions of the gun body 72 are bent at a right angle. The tip portion 73A is disposed adjacent to the two surfaces and is slidable along the longitudinal direction of the second surface. The tip portion 73A bends in the same direction as the tip portion 72A of the gun body 72, and the gun body 72 A welding gun 6A that includes an L-shaped sliding conductor 73 having a length reaching the tip, and that is supplied with a current output from the welding transformer 10 via a power supply cable 7, and the gun of the welding gun 6A A cylindrical inner electrode 85A provided between the distal end portion 72A of the main body 72 and the distal end portion 73A of the sliding conductor 73, electrically connected to the gun main body 72, and provided with an insulating ring 85C at the distal end. Shape With, integrated with the Suridoshirubedentai 73, the one-side electrode 85 made of the inner electrode 85A in the axial direction interpolation possible outer electrode 85B, in the resistance welding apparatus provided with,
The welding gun 6A is
A first fixed shaft 741 made of a cylindrical conductive metal member, connected to the negative electrode 24 of the welding transformer 10 via the power supply cable 7, and a cylindrical conductive metal member, A second fixed shaft 742 is provided that allows the first fixed shaft 741 to be inserted while maintaining a non-conductive state with the first fixed shaft 741 and is connected to the plus electrode 22 of the welding transformer 10 via the power supply cable 7. A fixed shaft portion 74 that supports the gun body 72 and the sliding conductor 73 rotatably about a central axis common to the first fixed shaft 741 and the second fixed shaft 742;
A first power feeding device 76 disposed between the gun main body 72 and the fixed shaft portion 74 of the welding gun 6 </ b> A and electrically connecting the first fixed shaft 741 of the fixed shaft portion 74 and the gun main body 72. When,
A second conductive shaft is disposed between the sliding conductor 73 of the welding gun 6A and the fixed shaft portion 74 and electrically connects the second fixed shaft 742 of the fixed shaft portion 74 and the sliding conductor 73. Two power feeders 77;
Further comprising
Each of the first power feeding device 76 and the second power feeding device 77 is
A first block body 761 having a three-dimensional shape that is concave in a plan view, the recessed portion being a semicircular groove, and a conductive metal member;
The first block body 761 is composed of substantially the same shape and the same member, and is disposed so as to face the surface side where the semicircular groove is formed toward the surface side where the semicircular groove of the first block body 761 is formed. A two-block body 762;
The first block body 761 is disposed in a compressed state between the surface side of the second block body 762 on which the semicircular groove is formed and the surface side of the second block body 762 on which the semicircular groove is formed. Coil springs 763 and 764 that act to separate the first block body 761 and the second block body 762;
Each of the first block body 761 and the second block body 762 has a cylindrical shape that partially fits with the semicircular groove, and at least one of the outer peripheral surface and the inner peripheral surface, from one open end. A bushing 765 made of a conductive metal member having at least one groove extending to the other open end;
Clamping mechanisms 766 and 767 that clamp the bush 765 by the first block body 761 and the second block body 762 by pulling at least one of the first block body 761 and the second block body 762 to the other side. When,
With
The first block body 761 and the second block body 762 are collectively referred to as a fixed portion, and a metal member fitted into the bush 765 is referred to as a movable portion, and an electric current flows between the fixed portion and the movable portion. Sometimes, by operating the clamping mechanism 766,767, the continuity between the fixed portion and the movable portion is achieved.
Resistance welding equipment. A primary core that is divided and wound into a plurality of portions around the annular magnetic core 25 composed of a parallel portion 25a and U-shaped curved portions 25b at both ends, and the parallel portion 25a of the annular magnetic core 25 with a gap 12a. A plurality of positive side coils are wound around the parallel part 25a of the annular magnetic core 25 together with the coil 12 and the primary coil 12 so as to be sandwiched one by one in the gaps 12a provided in the primary coil 12. 14 and a plurality of negative coils 16 are alternately arranged, and the plurality of positive coils 14 are all connected in parallel or all or a part thereof are connected in series, and the plurality of negative coils 16 are all connected in parallel, or all or part of them are connected in series, and the plurality of connected positive coils 14 and the plurality of negative coils 16 are connected in series to each other. A conductor group that electrically connects the terminals of the side coil 14 and the negative side coil 16, and the positive side coil 14 and the negative side coil 16 are placed on one surface by the conductor group. A connection board 62 for supporting and fixing is provided, and one terminal of the plurality of positive side coils 14 extends in a direction parallel to the parallel portion 25a of the annular magnetic core 25 on the other surface of the connection board 62. One terminal of the plurality of negative coils 16 extends in a direction parallel to the parallel portion 25a of the annular magnetic core 25 on the other surface side of the connection board 62. The other end of the positive side coil 14 and the negative side coil 16 is electrically connected to the second connecting electrode plate 46, and the other side of the connection substrate 62 is connected to the parallel portion 25 a of the annular magnetic core 25. Electricity is applied to the third connecting plate 48 extending in the parallel direction. A positive conductor 30 is connected to the first connecting electrode plate 44, a negative conductor 32 is connected to the second connecting electrode plate 46, and the positive conductor 30 and the negative conductor 32 are connected. Is a pair of conductor plates that are superimposed on each other on the other surface side of the connection substrate 62 via an insulating layer 31 disposed on a boundary surface extending in a direction away from the other surface. A rectifying element 18 sandwiched between a side conductor 30 and a first electrode plate 34 and having a negative electrode in contact with the positive electrode conductor 30 and a positive electrode in contact with the first electrode plate 34, the negative conductor 32 and a second electrode A rectifying element 20 sandwiched between plates 36 and having a negative electrode in contact with the negative conductor 32 and a positive electrode in contact with the second electrode plate 36, and the first electrode plate 34 and the second electrode plate 36 are supported. A third electrode plate 38 electrically connecting the two and a positive electrode 2 connected to the third electrode plate 38 2 and a negative electrode 24 connected to the third connecting electrode plate 48, a welding transformer 10 comprising:
A U-shaped gun body 72 in which both the distal end portion 72A and the proximal end portion 72B are bent at a right angle in the same direction, and a first surface on the opposite side to the first surface on the side where both end portions of the gun body 72 are bent at a right angle. The tip portion 73A is disposed adjacent to the two surfaces and is slidable along the longitudinal direction of the second surface. The tip portion 73A bends in the same direction as the tip portion 72A of the gun body 72, and the gun body 72 A welding gun 6B including an L-shaped sliding conductor 73 having a length reaching the tip;
The welding gun 6B is provided in a cylindrical shape having a distal end portion 72A of the gun body 72 and a distal end portion 73A of the sliding conductor 73, which is electrically connected to the gun body 72 and provided with an insulating ring 85C at the distal end. An inner electrode 85A, and a one-sided electrode 85 formed of a cylindrical shape and an outer electrode 85B integrated with the sliding conductor 73 and capable of inserting the inner electrode 85A in the axial direction;
In a resistance welding apparatus comprising:
The welding gun 6B
A first fixed shaft 741B made of a cylindrical conductive metal member, one end of which is directly connected to the negative electrode 24A of the welding transformer 10, and a cylindrical conductive metal member, the first fixed shaft 741B and The first fixed shaft 741B can be inserted while maintaining a non-energized state, and extends in a direction perpendicular to the central axis direction on the opening end side located on the same side as one end of the first fixed shaft 741B. The annular flange Ba has a second fixed shaft 742B directly connected to the plus electrode 22A of the welding transformer 10, and the gun body 72 and the sliding conductor 73 are A fixed shaft portion 74B that rotatably supports a central axis common to the first fixed shaft 741B and the second fixed shaft 742B as a rotation center;
A first power feeder 76 that electrically connects the first fixed shaft 741B of the fixed shaft portion 74B and the gun body 72;
A second power feeding device 77 that electrically connects the second fixed shaft 742B of the fixed shaft portion 74B and the sliding conductor 73;
Further comprising
Each of the first power feeding device 76 and the second power feeding device 77 is
A first block body 761 having a three-dimensional shape that is concave in a plan view, the recessed portion being a semicircular groove, and a conductive metal member;
The first block body 761 is composed of substantially the same shape and the same member, and is disposed so as to face the surface side where the semicircular groove is formed toward the surface side where the semicircular groove of the first block body 761 is formed. A two-block body 762;
The first block body 761 is disposed in a compressed state between the surface side of the second block body 762 on which the semicircular groove is formed and the surface side of the second block body 762 on which the semicircular groove is formed. Coil springs 763 and 764 that act to separate the first block body 761 and the second block body 762;
Each of the first block body 761 and the second block body 762 has a cylindrical shape that partially fits with the semicircular groove, and at least one of the outer peripheral surface and the inner peripheral surface, from one open end. A bushing 765 made of a conductive metal member having at least one groove extending to the other open end;
Clamping mechanisms 766 and 767 that clamp the bush 765 by the first block body 761 and the second block body 762 by pulling at least one of the first block body 761 and the second block body 762 to the other side. When,
With
The first block body 761 and the second block body 762 are collectively referred to as a fixed portion, and a metal member fitted into the bush 765 is referred to as a movable portion, and an electric current flows between the fixed portion and the movable portion. Sometimes, by operating the clamping mechanism 766,767, the continuity between the fixed portion and the movable portion is achieved.
Resistance welding equipment.