JP2013071159A - Spot welding equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide spot welding equipment that can obtain stable welding quality for spot-welding an object to be welded of a plate assembly superposed with plate materials.SOLUTION: The spot welding equipment includes: a static side electrode 19; a movable side electrode 29 which holds a member 100 to be welded, and then pressurize the member 100 in cooperation with this static side electrode 19; a sub-pressurization part 39 which adjoins the static side electrode 19, contacts with the member 100, and gives sub-pressurization force; and a movable conveyance means 34 of a rack and pinion mechanism which moves the movable side electrode 29 and the sub-pressurization member 39 together. The member 100 is held and pressurized by the static side electrode 19 and the movable side electrode 29, which then faces the sub-pressurization part 39 and the static side electrode 19 to contact with the member 100, so that spot welding is performed by the energization between the static side electrode 19 and the movable side electrode 29.

Description

  The present invention relates to a spot welding apparatus for spot welding a member to be welded in a plate assembly in which plate materials are overlapped.

  In general, spot welding in which a pair of welding electrodes are sandwiched between a pair of welding electrodes and energized between the electrodes for a certain period of time is widely performed for joining the plate materials such as the stacked steel plates.

  Here, for example, as shown in FIG. 9A, a thin plate 101 having a low rigidity, a plate assembly in which three plate materials of a first thick plate 102 and a second thick plate 103 having higher rigidity than the thin plate 101 are overlapped. When spot welding is performed on the member to be welded 100, when the member to be welded 100 is pressed by the movable side electrode 111 and the fixed side electrode 112, the thin plate 101 and the first thick plate 102 having low rigidity are moved upward. The bending causes a gap between the thin plate 101 and the first thick plate 102 and between the first thick plate 102 and the second thick plate 103. In this case, the contact area between the movable electrode 111 and the thin plate 101 is increased by the bending of the thin plate 101, whereas between the thin plate 101 and the first thick plate 102 and between the first thick plate 102 and the second thick plate 103. The contact area of the joint is reduced by the gap. For this reason, the current density between the movable side electrode 111 and the fixed side electrode 112 is higher on the second thick plate 103 side than on the thin plate 101 side, and the first thick plate 102 and the first thick plate 102 are larger than between the thin plate 101 and the first thick plate 102. The amount of heat generated locally between the two thick plates 103 increases.

  As a result, as shown in FIG. 9A, first, a nugget 105 is formed at a joint portion between the first thick plate 102 and the second thick plate 103, and the nugget 105 gradually becomes larger, and as shown in FIG. 9B. In this way, the thin plate 101 and the first thick plate 102 are welded. However, the amount of penetration between the thin plate 101 and the first thick plate 102 is small, the welding strength is unstable, and the welding quality varies. This problem is particularly noticeable as the first thick plate 102 and the second thick plate 103 are thicker and the nugget 105 is less likely to reach between the first thick plate 102 and the thin plate 101.

  As a countermeasure for this, for example, the spot welding method disclosed in Patent Document 1 spot welds a member 100 to be welded of three sheets of a thin plate 101, a first thick plate 102, and a second thick plate 103 as shown in FIG. Sometimes, the pressing force FU of the movable side electrode 125 on the thin plate 101 side is made smaller than the pressing force FL of the fixed side electrode 124 on the second thick plate 103 side, thereby joining the thin plate 101 and the first thick plate 102. The contact resistance of the first thick plate 102 and the second thick plate 103 decreases, and when the energization is performed between the movable side electrode 125 and the fixed side electrode 124, The amount of heat generated at the joint with the first thick plate 102 is increased, and the welding strength between the thin plate 101 and the first thick plate 102 is increased.

  As shown in FIG. 11, the spot welding apparatus used for carrying out this method has a spot welding apparatus 120 mounted on the wrist 116 of the welding robot 115. The welding robot 115 moves the spot welding device 120 to each spot position of the member to be welded 100 held by the clamper 118 to perform spot welding of the member to be welded 100.

  The spot welding device 120 includes a base portion 122 supported by a linear guide 121 fixed to a support bracket 117 attached to the wrist portion 116 so as to be movable up and down. The base portion 122 is provided with a fixed arm 123 extending downward. The fixed side electrode 124 is provided at the tip of the fixed arm 123.

  A pressure actuator 126 is mounted on the upper end of the base portion 122, and the movable side electrode 125 is attached to the lower end of the rod 127 that moves up and down by the pressure actuator 126 with respect to the fixed side electrode 124. A servo motor 128 is mounted on the upper end of the support bracket 117, and the base portion 122 moves up and down via the ball screw mechanism by the operation of the servo motor 128.

  Here, in accordance with teaching data stored in advance in a controller (not shown), the pressure FU applied by the movable electrode 125 located on the thin plate 101 side is made smaller than the pressure FL applied by the fixed electrode 124 (FU <FL).

  In order to make the pressure FU applied by the movable side electrode 125 smaller than the pressure applied FL by the fixed side electrode 124 in this way, the controller first raises the base portion 122 by the servo motor 128 to cause the fixed side electrode 124 to be welded. The movable electrode 125 is lowered by the pressure actuator 126 and brought into contact with the upper surface of the member to be welded 100.

  Next, the base portion 122 is pushed up by the servo motor 128. As the base portion 122 is pushed up, the pressing force FL of the fixed side electrode 124 is increased by the pushing amount of the base portion 122, and the pressing force FU by the movable side electrode 125 becomes smaller than the pressing force FL by the fixed side electrode 124 (FU < FL).

  As a result, when the movable side electrode 125 and the fixed side electrode 124 are energized, the current density at the joint between the thin plate 101 and the first thick plate 102 is increased, and the amount of heat generated is the first thick plate 102 and the second thickness. It increases relative to the amount of heat generated at the joint of the plate 103. Thereby, a good nugget with no bias is formed from the thin plate 101 to the second thick plate 103, and the welding strength can be ensured.

JP 2003-251469 A

  According to Patent Document 1, the fixed side electrode 124 is brought into contact with the second thick plate 103 of the member to be welded 100 held by the clamper 118, the movable side electrode 125 is brought into contact with the thin plate 101, and the base portion 122 is further fixed. By pushing up and making the pressure FU on the movable electrode 125 side smaller than the pressure FL on the fixed electrode 124 side, the current density between the thin plate 101 and the first thick plate 102 becomes relatively high, and the thin plate 101 and the first plate The amount of heat generated at the joint with the thick plate 102 can be secured, the amount of penetration increases, and the welding strength increases.

  However, the member to be welded 100 held by the clamper 118 is moved between the base portion 122 in a state where the member to be welded 100 is sandwiched and pressed by the fixed side electrode 124 and the movable side electrode 125, and the movable side electrode 125 is moved by the pressing force FL of the fixed side electrode 124. In order to reduce the applied pressure FU, a large load is required on the clamper 118 that holds the member to be welded 100. On the other hand, in a state where the holding position of the member to be welded 100 by the clamper 118 and the welding position are largely separated from each other, the member to be welded 100 is bent and deformed, and the applied pressure FL by the fixed side electrode 124 and the applied pressure FU by the movable side electrode 125 vary. It is difficult to secure a stable contact resistance between the thin plate 101 and the first thick plate 102 and a contact resistance between the first thick plate 102 and the second thick plate 103 due to the occurrence of There is a concern that the quality of spot welding may deteriorate due to variations.

  Therefore, the objective of this invention made | formed in view of this point is providing the spot welding apparatus which can obtain the outstanding welding quality in carrying out the spot welding of the to-be-welded member of the board assembly which piled up the board | plate material.

  The spot welding apparatus according to the first aspect of the present invention that achieves the above object includes a first welding electrode that moves between a pressurizing position and a retracted position, and a first welding electrode that is disposed opposite to the first welding electrode at the pressurizing position. A second welding electrode that clamps and pressurizes the member to be welded in cooperation with the one welding electrode, and a sub-contact that abuts the member to be welded adjacent to the second welding electrode and applies a sub-pressurizing force to the member to be welded. A sub-pressurizing unit that moves to a pressurizing position and a retracted position, and the sub-pressurizing member is moved from the retracted position in conjunction with the movement of the first welding electrode from the retracted position to the pressurizing position and from the pressurizing position to the retracted position. Movable transmission means for moving from the sub-pressurization position and the sub-pressurization position to the retracted position, the first welding electrode in the pressurization position contacting the member to be welded, the sub-pressurization unit in the sub-pressurization position, and the first A second welding electrode that is in contact with the member to be welded facing the welding electrode. It said member to be welded clamping pressurized, characterized in that the spot welding current is passed between the at 該挟 lifting pressurized first welding electrode and the second welding electrode by a.

  According to this, the pressurizing force by the second welding electrode and the subpressing force from the sub-pressurizing portion are applied to the member to be welded, and the pressurizing force by the first welding electrode is applied to face the second welding electrode. The pressure applied by the two welding electrodes is smaller than the pressure applied by the first welding electrode. Accordingly, a plate member having different rigidity, for example, a thin plate having low rigidity and a member to be welded in which the first thick plate and the second thick plate having high rigidity are stacked and pressed between the first welding electrode and the second welding electrode. When energized, the current density at the joint between the thin plate and the first thick plate is relatively increased, and excellent welding quality for the member to be welded is obtained.

  On the other hand, in conjunction with the movement of the first welding electrode from the retracted position to the pressurizing position and from the pressurizing position to the retracted position, the sub pressurizing member is moved from the retracted position to the subpressing position and from the subpressing position to the retracted position. By providing the movable transmission means, reliable interlocking between the first welding electrode and the sub-pressurizing member can be ensured, the actuator for operating the sub-pressurizing member can be omitted, and the spot welding apparatus can be reduced in size and weight. .

  According to a second aspect of the present invention, there is provided a first welding electrode that moves between a pressurizing position and a retracted position, and a first welding electrode that is disposed opposite the first welding electrode at the pressing position and cooperates with the first welding electrode. A second welding electrode that moves between a pressurization position for sandwiching and pressurizing the welding member and a retreating position, and abutting the member to be welded adjacent to the second welding electrode to apply a sub-pressurizing force to the member to be welded The second welding electrode is moved from the retraction position to the pressurization position and from the pressurization position to the retraction position in conjunction with the sub-pressurization unit and the movement of the first welding electrode from the retraction position to the pressurization position and from the pressurization position to the retraction position. Movable transmission means for moving the welded member between the first welding electrode and the sub-pressurizing portion in contact with the welded member and the second welding electrode in the pressurizing position. And between the first welding electrode and the second welding electrode in the sandwiched pressure state Characterized by spot welding to conductive.

  According to this, the pressurizing force by the second welding electrode and the subpressing force from the sub-pressurizing portion are applied to the member to be welded, and the pressurizing force by the first welding electrode is applied to face the second welding electrode. The pressure applied by the two welding electrodes is smaller than the pressure applied by the first welding electrode. Thereby, the welding member which piled the plate material from which rigidity differs was pinched and pressurized, and the welding quality with respect to the to-be-welded member is obtained by electricity supply between a 1st welding electrode and a 2nd welding electrode.

  On the other hand, a movable transmission that moves the first welding electrode from the retracted position to the pressurizing position and from the pressurizing position to the retracted position in conjunction with the movement of the first welding electrode from the retracted position to the pressurizing position and from the pressurizing position to the retracting position. By providing the means, reliable interlocking of the first welding electrode and the second welding electrode can be ensured, the actuator for operating the second welding electrode can be omitted, and the spot welding apparatus can be reduced in size and weight.

  According to a third aspect of the present invention, in the spot welding apparatus according to the first or second aspect, the movable transmission means is a rack and pinion mechanism. According to this, the movable transmission means can be configured by a rack and pinion mechanism that can obtain a reliable operation with a simple configuration.

  The invention according to claim 4 is the spot welding apparatus according to claim 1 or 2, wherein the movable transmission means is a link mechanism. According to this, the movable transmission means can be configured by a link mechanism that can obtain a reliable operation with a simple configuration.

  According to the present invention, the pressing force by the second welding electrode and the sub-pressing force from the sub-pressurizing portion are applied to the member to be welded, and the pressing force by the first welding electrode is applied to face the second welding electrode. The pressure applied by the two welding electrodes is smaller than the pressure applied by the first welding electrode. As a result, when a member to be welded on which plate members having different rigidity are stacked is pressed and energized between the first welding electrode and the second welding electrode, excellent welding quality for the member to be welded is obtained.

It is a block diagram of the spot welding apparatus in 1st Embodiment. It is an operation | movement outline explanatory drawing of the spot welding apparatus typically shown. It is a block diagram of the spot welding apparatus in 2nd Embodiment. It is an operation | movement outline explanatory drawing of the spot welding apparatus typically shown. It is a block diagram of the spot welding apparatus in 3rd Embodiment. It is an operation | movement outline explanatory drawing of the spot welding apparatus typically shown. It is a block diagram of the spot welding apparatus in 4th Embodiment. It is an operation | movement outline explanatory drawing of the spot welding apparatus typically shown. It is explanatory drawing which shows the outline | summary of the conventional spot welding. It is explanatory drawing which shows the outline | summary of the conventional spot welding. It is explanatory drawing which shows the outline | summary of the conventional spot welding.

  Hereinafter, embodiments of a spot welding apparatus according to the present invention will be described with reference to the drawings.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram of a spot welding apparatus, and FIG. In the description of the spot welding apparatus, the upper and lower parts in FIG. 1 are referred to as the upper and lower parts in the spot welding apparatus for convenience.

  Prior to the description of the spot welding apparatus 1, the member to be welded 100 will be described. As shown in FIG. 2, a member 100 to be welded includes a thin plate 101 having a low rigidity, a first thick plate 102 having a thickness greater than that of the thin plate 101, and a third thick plate 103 each having a higher rigidity. Consists of.

  The configuration of the spot welding apparatus 1 will be described with reference to FIG. The spot welding apparatus 1 has a support bracket 3 attached to a wrist 81 of a welding robot 80 via an equalizer unit 2 as indicated by an imaginary line, and a fixed arm 10, a pressure actuator 20, a secondary additive are attached to the support bracket 3. A pressure applying means 30 and a welding transformer 8 are provided.

  A linear guide 4 that extends in the vertical direction and is configured by the guide rail 4 a and the slider 4 b is disposed on the support bracket 3. The base end portion 10 a of the fixed arm 10 is coupled to the slider 4 b of the linear guide 4. The fixed arm 10 includes a fixed arm main body 11 extending downward from a base end portion 10a coupled and supported by the slider 4b, and an electrode holding portion 12 bent in an L shape from the distal end of the fixed arm main body 11, and holds the electrode. The fixed electrode 19 is attached to the tip of the part 12 with the top end 19a facing upward.

  On the other hand, the auxiliary pressure actuator 13 is provided on the support bracket 3. The sub-pressurizing actuator 13 has a linear motion portion 15 constituted by a servo motor 14 and a ball screw mechanism, and the rod 16 of the linear motion portion 15 moves up and down by the operation of the servo motor 14. The distal end of the rod 16 is connected to the proximal end portion 10 a of the fixed arm 10.

  By the operation of the servo motor 14 of the sub-pressurizing actuator 13, the fixed arm 10 whose base end portion 10a is fixedly supported by the linear guide 4 moves between the retracted position of the descending movement end and the pressing position of the ascending movement end. . As the fixed arm 10 moves, the fixed electrode 19 attached to the fixed arm 10 moves along the central axis L between the retracted position and the pressure position.

  The pressure actuator 20 has a linear motion part 22 constituted by a servo motor 21 and a ball screw mechanism, and the rod 23 of the linear motion part 22 is reciprocated up and down by the operation of the servo motor 21. A movable arm 24 is provided at the lower end of the rod 23 of the linear motion portion 22, and is coaxial with the fixed side electrode 19 provided on the fixed arm 10 at the distal end of the movable arm 24, that is, on the central axis L so as to face the fixed electrode 19. A movable electrode 29 is provided.

  By operating the servo motor 21, the movable side electrode 29 holds the member to be welded 100 in cooperation with the retracted position separating upward from the fixed side electrode 19 and the fixed side electrode 19 in the pressurizing position, and applies pressure. It moves up and down along the central axis L between the pressurizing position.

  The auxiliary pressure applying means 30 is supported by the linear guide 5 composed of the guide rail 5a and the slider 5b disposed on the support bracket 3 between the fixed arm body 11 and the movable arm 24 of the fixed arm 10 so as to be movable up and down. The auxiliary pressure arm 31 is provided. The secondary pressure arm 31 has a base end 31 a supported by the slider 5 b of the linear guide 5 and extends downward from the base end 31 a and a central axis from the distal end of the secondary pressure arm main body 32. A sub-pressurizing part support part 33 that is bent in the L direction and extends, and a sub-pressurizing part that is formed integrally with or separately from the sub-pressurizing part support part 33 at the tip of the sub-pressurizing part support part 33 39. The sub-pressurizing portion 39 is a block shape having a circular arc at the tip and having an upper surface 39a and a lower surface 39b, and a U-shaped groove-shaped electrode penetration recess allowing the penetration of the fixed side electrode 19 and the movable side electrode 29 is formed at the center of the tip. To do.

  A movable transmission means 34 is provided between the movable arm 24 and the sub pressure arm 31 to operate the sub pressure arm 31 in conjunction with the movement of the movable arm 24. The movable transmission means 34 includes a drive side rack 35 provided on the movable arm 24 and a driven side rack 36 provided on the sub pressure arm main body 32 so as to face the drive side rack 35. And a rack-and-pinion mechanism that has a pinion 38 that is rotatably supported via a rotary shaft 37 and that meshes with the drive-side rack 35 and the driven-side rack 36.

  As a result, the drive side rack 35, the pinion 38, the driven side rack 36, and the like are configured in conjunction with the downward movement of the movable side electrode 29 from the retracted position to the pressure position by the operation of the servo motor 21 of the pressure actuator 20. The auxiliary pressure arm 31 and the auxiliary pressure unit 39 are moved upward from the retracted position to the auxiliary pressure position via the movable transmission means 34 of the rack and pinion mechanism. Similarly, the sub pressure arm 31 and the sub pressure unit 39 move from the sub pressure position to the retreat position in conjunction with the upward movement of the movable electrode 29 from the pressure position to the retreat position.

  The output terminal of the welding transformer 8 serving as a power source is connected to the fixed side electrode 19 through the bus bar and the fixed arm 10 so as to be energized, and the other output terminal is energized to the movable side electrode 29 through the bus bar and the movable arm 24 etc. Connect as possible.

  In addition, teaching data of the welding robot 80 is stored in a welding robot controller (not shown), and the teaching data includes an operation program for sequentially spot-welding each welding spot position of the welded member 100 and each welding spot, that is, a welding position. The position and attitude of the spot welding apparatus 1 in FIG. A welding controller (not shown) includes an operation program of the welding apparatus 1 and an operation control of the pressure actuator 20, the sub-pressurizing application means 30, and the welding transformer 8.

  As shown in FIG. 1, the spot welding apparatus 1 configured as described above operates the welding robot 80 with the fixed electrode 19, the movable electrode 29, and the auxiliary pressurizing unit 39 held in the retracted position. For example, the upper surface 39a of the sub-pressurizing unit 39 is abutted from below and positioned at the spot position that is the welding position of the welding member 100. In this positioned state, the upper surface 39a of the sub-pressurizing portion 39 contacts the thin plate 101 of the member to be welded 100 from below, while the top end 19a of the fixed electrode 19 faces the thin plate 101 with a gap, and The top end 29a of the movable electrode 29 faces the second thick plate 103 with a gap.

  In this positioned state, the servo motor 21 of the pressurizing actuator 20 operates the movable side electrode 29 via the movable arm 24 and the like, and the sub pressure unit 39 via the movable transmission means 34 and the sub pressurizing arm 31 and the like. Each moves from the retracted position to the pressurizing position and the sub-pressurizing position, and is sandwiched between the movable electrode 29 and the sub-pressurizing unit 39 to apply pressure. On the other hand, the operation of the servo motor 14 of the sub-pressurizing actuator 13 moves the fixed side electrode 19 provided on the fixed arm 10 to the pressurizing position so as to contact the welded member 100 and the movable side electrode 29 at the pressurizing position. The welding position of the member to be welded 100 is clamped and pressurized.

  FIG. 2 schematically shows a state in which the member to be welded 100 is sandwiched and pressurized by the fixed side electrode 19 and the movable side electrode 29 and the member to be welded 100 is sandwiched and pressurized by the movable side electrode 29 and the sub-pressurizing unit 39. As described above, the pressing force FU by the movable electrode 29 is applied to the second thick plate 103 from above, and the pressing force FL by the fixed electrode 19 and the sub pressing force Fα by the sub pressurizing unit 39 are applied to the thin plate 101 from below. .

  In this case, the pressure applied by the pressurizing actuator 20 acts on the sub-pressurizing unit 39 via the movable arm 24 via the movable side electrode 29, the movable transmission means 34, the sub-pressurizing arm 31, and the like. Acting on the fixed side electrode 19 via the actuator 13 and the fixed arm 10, the pressure applied by the sub-pressurizing actuator 13 acts on the fixed side electrode 19, and the second thick plate 103 is applied by the movable electrode 29 acting from above. The sum of the pressure FU and the pressing force FL by the fixed electrode 19 acting on the thin plate 101 from below and the sub pressing force Fα by the sub pressurizing unit 39 are equal (FU = FL + Fα).

  As a result, the applied pressure FL acting on the thin plate 101 from the fixed side electrode 19 is given a pressure obtained by subtracting the auxiliary pressure Fα by the auxiliary pressure unit 39 from the pressure FU by the movable electrode 29 (FL = FU−). Fα). Thus, the pressure FL of the fixed side electrode 19 acting on the thin plate 101 side is made smaller than the pressure FU of the movable side electrode 29 acting on the second thick plate 103 side (FL <FU). The contact pressure at the junction of the first thick plate 102 is smaller than the contact pressure between the first thick plate 102 and the second thick plate 103.

  The movable side electrode 29, the fixed side electrode 19, and the sub-pressurizing unit 39 sandwich and press the member to be welded 100 so that the pressing force FL of the fixed side electrode 19 positioned on the thin plate 101 side is positioned on the second thick plate 103 side. The welding transformer 8 is energized for a predetermined time and welded between the movable side electrode 29 and the fixed side electrode 19 in a state where the applied pressure FU is smaller than the applied pressure FU of the movable side electrode 29. When the movable electrode 29 and the fixed electrode 19 are energized, the contact resistance between the thin plate 101 and the first thick plate 102 is relatively large and the current density is increased, and the thin plate 101 and the first thickness are increased. The amount of heat generated at the junction of the plate 102 increases relatively with respect to the amount of heat generated at the junction of the first thick plate 102 and the second thick plate 103, and the current density increases from the thin plate 101 to the second thick plate 103. Good welding with no bias is performed, and welding strength and welding quality can be secured.

  According to the present embodiment configured as described above, the auxiliary pressure Fα is applied from the auxiliary pressurizing portion 39 to the member to be welded 100 which is pressurized by the fixed side electrode 19 and the movable side electrode 29, and the fixed side electrode 19. The welding pressures FL and FU by the movable side electrode 29 are controlled to improve the welding quality for the member to be welded 100 in which plate materials having different rigidity are stacked.

  Further, in conjunction with the movement of the movable electrode 29 from the retracted position to the pressurizing position and from the pressurizing position to the retracting position, the sub-pressurizing member 39 is moved from the retracting position to the sub-pressurizing position and from the sub-pressurizing position to the retracting position. By providing the movable transmission means 34 of the rack-and-pinion mechanism, the movable side electrode 29 and the sub-pressurizing member 39 can be reliably interlocked, and the actuator for operating the sub-pressurizing member 39 can be omitted. The size and weight of the welding apparatus 1 can be reduced. Further, as the spot welding apparatus 1 is reduced in weight and size, the attitude control of the spot welding apparatus 1 becomes easier, the operation control of the welding robot 80 is simplified, and the load on the welding robot 80 can be reduced.

(Second Embodiment)
A second embodiment of the present invention will be described with reference to FIGS. FIG. 3 is a block diagram of the spot welding apparatus, and FIG. 3 and 4, parts corresponding to those in FIGS. 1 and 2 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The spot welding apparatus 1 includes a support bracket 3 attached to a wrist 81 of a welding robot 80 via an equalizer unit 2. The support bracket 3 has a fixed arm 10, a pressure actuator 20, a sub-pressure applying unit 40, and the like. A welding transformer 8 is provided. The pressure actuator 20 and the fixed arm 10 are configured in the same manner as in the first embodiment.

  The auxiliary pressure applying means 40 is supported by the linear guide 6 constituted by the guide rail 6a and the slider 6b disposed on the support bracket 3 between the fixed arm body 11 and the movable arm 24 of the fixed arm 10 so as to be movable up and down. The auxiliary pressure arm 41 is provided. The secondary pressure arm 41 has a base end portion 41 a supported by the slider 6 b of the linear guide 6, and extends downward from the base end portion 41 a and a central axis line from the distal end of the secondary pressure arm main body 42. It has a sub-pressurizing part support part 43 that is bent in the L direction and has a sub-pressurizing member 39 at the tip.

  A movable transmission means 44 is provided between the fixed arm 10 and the auxiliary pressure arm 41 to operate the auxiliary pressure arm 41 in conjunction with the movement of the fixed arm 10. The movable transmission means 44 includes a drive side rack 45 provided on the fixed arm body 11 of the fixed arm 10 and a driven side rack 46 provided on the sub pressure arm body 42 so as to face the drive side rack 45. The rack and pinion mechanism includes a pinion 48 that is rotatably supported by the support bracket 3 via a rotary shaft 47 and that meshes with the driving side rack 45 and the driven side rack 46.

  As a result, the driving side rack 45, the pinion 48, the driven side rack 45, etc. are configured in conjunction with the upward movement of the stationary side electrode 19 from the retracted position to the pressing position due to the operation of the servo motor 14 of the auxiliary pressure actuator 13. The sub-pressurizing arm 41 and the sub-pressurizing unit 39 are moved downward from the retracted position to the sub-pressurizing position via the movable transmission means 44 of the rack-and-pinion mechanism that can obtain the reliable operation. Similarly, in conjunction with the downward movement of the fixed electrode 19 from the pressure position to the retreat position, the sub pressure arm 41 and the sub pressure section 39 are moved upward from the sub pressure position to the retreat position.

  In this way, in the spot welding apparatus 1, the fixed side electrode 19, the sub-pressurizing portion 39, and the movable side electrode 29 are held at the retracted position as shown in FIG. For example, the lower surface 39b of the sub-pressurizing unit 39 is positioned by contacting from above.

  In this positioned state, the fixed side electrode 109 and the sub pressurization unit 39 are moved from the retracted position to the pressurization position and the sub pressurization position by the operation of the servo motor 14 of the sub pressurization actuator 13, respectively. And the sub-pressurizing unit 39 and pressurizing. On the other hand, when the servo motor 21 of the pressurizing actuator 20 is operated, the movable side electrode 29 provided on the movable arm 24 is moved to the pressurizing position so as to come into contact with the member 100 to be welded and the fixed side electrode 19 at the pressurizing position is covered. The welding position of the welding member 100 is clamped and pressurized.

  In this case, as shown in FIG. 4, the applied pressure FL by the fixed side electrode 19 acting on the second thick plate 103 from below and the applied pressure FU by the movable side electrode 29 acting on the thin plate 101 from above and the sub pressurizing unit 39. Therefore, the sum of the sub-pressurizing forces Fα is equal (FL = FU + Fα).

  As a result, the pressing force FU acting on the thin plate 101 from the movable electrode 29 is given a pressing force obtained by subtracting the sub pressing force Fα by the sub pressurizing unit 39 from the pressing force FL by the fixed electrode 19 (FU = FL−). Fα). Thus, the pressure FU of the movable side electrode 29 acting on the thin plate 101 side becomes smaller than the pressure FL of the fixed side electrode 19 acting on the second thick plate 103 side (FU <FL).

  As described above, the member 100 to be welded is sandwiched and pressed by the fixed side electrode 19, the movable side electrode 29, and the sub-pressurizing unit 39, and the applied pressure FU of the movable side electrode 29 located on the thin plate 101 side is changed to the second thick plate 103. In a state in which the pressure is smaller than the pressure FL of the fixed side electrode 19 positioned on the side, welding is performed between the movable transformer 8 and the movable side electrode 29 and the fixed side electrode 19 for a predetermined time. When current is passed between the movable side electrode 29 and the fixed side electrode 19, the current density at the junction between the thin plate 101 and the first thick plate 102 becomes relatively high, and the thin plate 101 changes to the second thick plate 103. Good welding without uneven current density is performed, and welding strength and welding quality can be ensured.

  According to the present embodiment configured as described above, the auxiliary pressure Fα is applied from the auxiliary pressurizing portion 39 to the member to be welded 100 which is pressurized by the fixed side electrode 19 and the movable side electrode 29, and the fixed side electrode 19. The welding pressures FL and FU by the movable side electrode 29 are controlled to improve the welding quality for the member to be welded 100 in which plate materials having different rigidity are stacked.

  Further, in conjunction with the movement of the stationary electrode 19 from the retracted position to the pressurizing position and from the pressurizing position to the retracted position, the sub-pressurizing member 39 is moved from the retracted position to the sub-pressurizing position and from the sub-pressurizing position to the retracted position. By providing the movable transmission means 44 of the rack-and-pinion mechanism, the fixed-side electrode 19 and the sub-pressurizing member 39 can be surely interlocked, and the actuator for operating the sub-pressurizing member 39 can be omitted. The size and weight of the welding apparatus 1 can be reduced. Further, as the spot welding apparatus 1 is reduced in weight and size, the attitude control of the spot welding apparatus 1 becomes easier, the operation control of the welding robot 80 is simplified, and the load on the welding robot 80 can be reduced.

(Third embodiment)
A third embodiment of the present invention will be described with reference to FIGS. FIG. 5 is a block diagram of the spot welding apparatus, and FIG. In FIGS. 5 and 6, parts corresponding to those in FIGS. 1 and 2 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The spot welding apparatus 1 has a support bracket 3 attached to a wrist 81 of a welding robot 80 via an equalizer unit 2 as indicated by an imaginary line, and a fixed arm 10, a pressure actuator 20, a secondary additive are attached to the support bracket 3. A pressure applying means 50 and a welding transformer 8 are provided.

  A linear guide 7 is provided on the support bracket 3, and the base end portion 10 a of the fixed arm 10 is supported by the linear guide 7 so as to be movable up and down. The fixed arm 10 includes a fixed arm main body 11 extending downward from the base end portion 10 a and an electrode holding portion 12 bent in an L shape from the tip of the fixed arm main body 11. The electrode 19 is attached.

  Sub-pressure applying means 50 is provided between the movable arm 24 and the fixed arm 10. The sub pressurizing application means 50 includes a sub pressurizing arm 51 whose base end portion 51 a is supported by the support bracket 3 between the fixed arm main body 11 and the movable arm 24 of the fixed arm 10. The sub pressure arm 51 has a sub pressure arm body 52 extending downward from the base end portion 51 a and a sub pressure portion support portion 53 that bends in the direction of the central axis L from the tip of the sub pressure arm body 52. The auxiliary pressure unit 39 is provided at the tip of the auxiliary pressure unit support part 53.

  A movable transmission means 54 for operating the fixed arm 10 in conjunction with the movement of the movable arm 24 is provided between the movable arm 24 provided in the pressure actuator 20 and the base end portion 10 a of the fixed arm 10. The movable transmission means 54 has a drive side rack 55 provided on the movable arm 24 and a driven side rack 56 provided on the base end portion 10a of the fixed arm 10 so as to face the drive side rack 55, and is supported. A rack and pinion mechanism having a pinion 58 that is rotatably supported by the bracket 3 via a rotating shaft 57 and that meshes with the driving side rack 55 and the driven side rack 56 is configured.

  Accordingly, the driving side rack 55, the pinion 58, the driven side rack 56, and the like are configured in conjunction with the downward movement of the movable side electrode 29 from the retracted position to the pressing position by the operation of the servo motor 21 of the pressure actuator 20. The fixed arm 10 and the fixed electrode 19 are moved upward from the retracted position to the pressurizing position via the movable transmission means 54 of the rack and pinion mechanism. Similarly, the fixed arm 10 and the fixed electrode 19 are moved from the pressurization position to the retracted position in conjunction with the upward movement of the movable electrode 29 from the pressurization position to the retracted position.

  In this way, in the spot welding apparatus 1, as shown in FIG. 5, the fixed side electrode 19, the sub-pressurizing portion 39, and the movable side electrode 29 are held at the retracted position, and the spot welding device 1 is at the spot position that becomes the welding position of the welded member 100. For example, the upper surface 39a of the sub-pressurizing unit 39 is positioned by contacting from below. In this positioned state, the operation of the servo motor 21 of the pressure actuator 20 moves the movable electrode 29, the movable transmission means 54 and the fixed arm 10 fixed side electrode 19 from the retracted position to the pressurized position via the movable arm 24, respectively. The movable side electrode 29 and the fixed side electrode 19 are sandwiched and pressurized.

  When the member to be welded 100 is clamped and pressed by the fixed side electrode 15 and the movable side electrode 29, the reaction force from the movable side electrode 29 is supplied through the support bracket 3 that supports the pressure actuator 20 to the sub-pressure applying arm. 51, the sub-pressurizing unit 33 presses against the member to be pressed 100 and applies the sub-pressurizing force Fα.

  In this case, as shown in FIG. 6, the pressure applied by the pressurizing actuator 20 acts on the thin plate 101 from the fixed side electrode 19 and the sub-pressurizing unit 33, and the second side from the movable side electrode 29 faces the fixed side electrode 19. A pressing force FU by the movable electrode 25 acting on the thick plate 103 and acting on the second thick plate 103 from above, a pressing force FL by the fixed side electrode 19 acting on the thin plate 101 from below, and a sub-pressurizing force by the sub-pressurizing unit 39. The sum of Fα becomes equal (FU = FL + Fα). As a result, the pressing force FL of the fixed side electrode 19 acting on the thin plate 101 side becomes smaller than the pressing force FU of the movable side electrode 29 acting on the second thick plate 103 side (FL <FU).

  The fixed electrode 19, the movable electrode 29, and the sub-pressurizing unit 39 sandwich and press the member to be welded 100 so that the pressure FL of the fixed electrode 19 positioned on the thin plate 101 side is positioned on the second thick plate 103 side. The welding transformer 8 is energized for a predetermined time and welded between the movable side electrode 29 and the fixed side electrode 19 in a state where the applied pressure FU is smaller than the applied pressure FU of the movable side electrode 29. When current is passed between the movable side electrode 29 and the fixed side electrode 19, the current density at the junction between the thin plate 101 and the first thick plate 102 becomes relatively high, and the thin plate 101 changes to the second thick plate 103. Good welding without uneven current density is performed, and welding strength and welding quality can be ensured.

  According to the present embodiment configured as described above, the auxiliary pressure Fα is applied from the auxiliary pressurizing portion 39 to the member to be welded 100 which is pressurized by the fixed side electrode 19 and the movable side electrode 29, and the fixed side electrode 19. The welding pressures FL and FU by the movable side electrode 29 are controlled to improve the welding quality for the member to be welded 100 in which plate materials having different rigidity are stacked.

  In addition, by providing the movable transmission means 54 of the rack and pinion mechanism that moves the fixed side electrode 19 in conjunction with the movement of the movable side electrode 29, it is possible to ensure reliable linkage between the movable side electrode 29 and the fixed side electrode 19. The omission of the actuator for operating the fixed side electrode 19 is obtained, and the spot welding apparatus 1 can be reduced in size and weight. As the spot apparatus 1 is reduced in size and weight, the attitude control of the spot welding apparatus 1 becomes easier, the operation control of the welding robot 80 is simplified, and the load on the welding robot 80 can be reduced.

(Fourth embodiment)
A fourth embodiment of the present invention will be described with reference to FIGS. FIG. 7 is a configuration diagram of the spot welding apparatus, and FIG. 8 is a schematic operation explanatory diagram schematically showing. 7 and 8, parts corresponding to those in FIGS. 1 and 2 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The spot welding apparatus 1 has a support bracket 3 attached to a wrist 81 of a welding robot 80 via an equalizer unit 2, and the support arm 3 has a fixed arm 10, a pressure actuator 20, a sub-pressure applying means 60, and welding. A transformer 8 is provided.

  The base end portion 10a of the fixed arm 10 is supported by the support bracket 3 via the linear guide 7 so as to be movable up and down. The fixed arm 10 includes a fixed arm main body 11 extending downward from the base end portion 10 a and an electrode holding portion 12 bent in an L shape from the tip of the fixed arm main body 11. The electrode 19 is attached.

  Sub-pressurizing application means 60 is provided between the movable arm 23 and the fixed arm 10. The auxiliary pressure applying means 60 includes an auxiliary pressure arm 61 in which the base end portion 61 a is supported by the support bracket 3 between the fixed arm main body 11 and the movable arm 24 of the fixed arm 10. The sub pressure arm 61 has a sub pressure arm main body 62 extending downward from the base end portion 61a and a sub pressure portion support portion 63 bent in the direction of the central axis L from the tip of the sub pressure arm main body 62. The auxiliary pressure unit 39 is provided at the tip of the auxiliary pressure unit support part 63.

  A movable transmission means 64 for operating the fixed arm 10 in conjunction with the movement of the movable arm 24 is provided between the movable arm 24 provided in the pressure actuator 20 and the base end portion 10 a of the fixed arm 10. The movable transmission means 64 includes a drive side arm 67 and a driven side arm 68 that are supported by the support bracket 3 via a rotation shaft 65 so as to be rotatable and extend toward the movable arm 23 side and the fixed arm body 11 side. An interlocking arm 66 is provided, and an elongated engagement hole 67a and engagement hole 68a are formed in the driving side arm 67 and the driven side arm 68, respectively. On the other hand, a drive shaft 71 whose top is movably locked in the engagement hole 67a is disposed on the movable arm 24, and a driven shaft 72 whose top is movably locked in the engagement hole 68a is provided on the fixed arm main body 11.

  As a result, in conjunction with the downward movement of the movable electrode 29 from the retracted position to the pressure position by the operation of the servo motor 21 of the pressure actuator 20, the operation is surely performed by the drive shaft 71, the interlock arm 66, the driven shaft 72, and the like. The fixed arm 10 and the fixed electrode 19 are moved upward from the retracted position to the pressurizing position via the movable transmission means 64 of the simple link mechanism. Similarly, in conjunction with the upward movement of the movable electrode 29 from the pressure position to the retracted position, the fixed arm 10 and the fixed electrode 19 are moved downward from the pressure position to the retracted position.

  In this way, in the spot welding apparatus 1, as shown in FIG. 6, the fixed-side electrode 19, the sub-pressurizing unit 39, and the movable-side electrode 29 are held at the retracted position, and the spot welding device 1 is at the spot position that becomes the welding position of the member to be welded 100. For example, the upper surface 39a of the sub-pressurizing unit 39 is positioned by contacting from below.

  In this positioned state, the movable side electrode 29 is moved from the retracted position to the pressure position via the movable arm 24 by the operation of the servo motor 21 of the pressure actuator 20, and via the movable transmission means 64 and the fixed arm 10. Then, the fixed electrode 19 is moved from the retracted position to the pressurizing position, and the member to be welded 100 is sandwiched and pressed by the movable electrode 29 and the fixed electrode 19.

  As the member to be welded 100 is sandwiched and pressed by the fixed side electrode 15 and the movable side electrode 29, the reaction force from the welded member 100 side to the movable side electrode 29 supports the pressure actuator 20 and the pressure actuator 20. Is transmitted to the sub-pressurizing application arm 61 through the supporting bracket 3, and the sub-pressurizing unit 33 is pressed against the member to be pressurized 100 to apply the sub-pressurizing force Fα.

  In this case, as shown in FIG. 8, the pressure applied by the pressurizing actuator 20 acts on the thin plate 101 from the fixed side electrode 19 and the sub-pressurizing unit 33, and the second side from the movable side electrode 29 faces the fixed side electrode 19. A pressing force FU by the movable electrode 25 acting on the thick plate 103 and acting on the second thick plate 103 from above, a pressing force FL by the fixed side electrode 19 acting on the thin plate 101 from below, and a sub-pressurizing force by the sub-pressurizing unit 39. The sum of Fα becomes equal (FU = FL + Fα).

  As a result, the applied pressure FL of the fixed electrode 19 acting on the thin plate 101 side becomes smaller than the applied pressure FU of the movable electrode 29 acting on the second thick plate 103 side (FL <FU). The fixed electrode 19, the movable electrode 29, and the sub-pressurizing unit 39 sandwich and press the member to be welded 100 so that the pressure FL of the fixed electrode 19 positioned on the thin plate 101 side is positioned on the second thick plate 103 side. The welding transformer 8 is energized for a predetermined time and welded between the movable side electrode 29 and the fixed side electrode 19 in a state where the applied pressure FU is smaller than the applied pressure FU of the movable side electrode 29. When the movable electrode 29 and the fixed electrode 19 are energized, the current density at the joint between the thin plate 101 and the first thick plate 102 is relatively high, and the thin plate 101 extends from the second thick plate 103. Thus, good welding without current density bias is performed, and welding strength and welding quality can be ensured.

  According to the present embodiment configured as described above, the auxiliary pressure Fα is applied from the auxiliary pressurizing portion 39 to the member to be welded 100 which is pressurized by the fixed side electrode 19 and the movable side electrode 29, and the fixed side electrode 19. The welding pressures FL and FU by the movable side electrode 29 are controlled to improve the welding quality for the member to be welded 100 in which plate materials having different rigidity are stacked.

  In addition, since the movable transmission means 64 of the link mechanism that moves the fixed side electrode 19 in conjunction with the movement of the movable side electrode 29 is provided, the movable side electrode 29 and the fixed side electrode 19 can be reliably interlocked and fixed. The omission of the actuator that operates the side electrode 19 is obtained, and the spot welding apparatus 1 can be reduced in size and weight. As the spot apparatus 1 is reduced in size and weight, the attitude control of the spot welding apparatus 1 becomes easier, the operation control of the welding robot 80 is simplified, and the load on the welding robot 80 can be reduced.

  The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the invention. For example, in the first embodiment and the second embodiment, the movable transmission means 34 and 44 are configured by a rack and pinion mechanism, but may be configured by a link mechanism like the movable transmission means 64 of the fourth embodiment. it can.

DESCRIPTION OF SYMBOLS 1 Spot welding apparatus 10 Fixed arm 13 Sub pressurization actuator 19 Fixed side electrode (1st welding electrode, 2nd welding electrode)
20 Pressurizing actuator 24 Movable arm 29 Movable electrode (first welding electrode, second welding electrode)
30 Sub-pressure applying means 31 Sub-pressure arm 39 Sub-pressure part 34 Movable transmission means 40 Sub-pressure application means 41 Sub-pressure arm 44 Movable transmission means 50 Sub-pressure application means 51 Sub-pressure arm 52 Sub-pressure Arm main body 53 Sub pressurizing part support part 54 Movable transmission means 60 Sub pressurization giving means 61 Sub pressurization arm 64 Movable transmission means 80 Welding robot 100 To-be-welded member

Claims (4)

A first welding electrode that moves between a pressure position and a retracted position;
A second welding electrode that is disposed opposite to the first welding electrode at the pressurizing position and presses the member to be welded in cooperation with the first welding electrode;
A sub-pressurizing portion that abuts on the member to be welded adjacent to the second welding electrode and applies a sub-pressurizing force to the member to be welded, and a sub-pressurizing unit that moves to a retracted position;
In conjunction with the movement of the first welding electrode from the retracted position to the pressurizing position and from the pressurizing position to the retracted position, the sub pressurizing member is moved from the retracted position to the subpressing position and from the subpressing position to the retracted position. Movable transmission means,
The first welding electrode at the pressurizing position in contact with the member to be welded, the sub pressurizing portion at the sub pressurizing position, and the second welding electrode in contact with the member to be welded facing the first welding electrode. A spot welding apparatus characterized in that a welding member is sandwiched and pressurized and spot welding is performed by energizing between the first welding electrode and the second welding electrode in the sandwiched and pressurized state. A first welding electrode that moves between a pressure position and a retracted position;
A second welding electrode which is disposed opposite to the first welding electrode in the pressurizing position and moves between a pressurizing position and a retracted position to sandwich and pressurize a member to be welded in cooperation with the first welding electrode;
A sub-pressurizing section that abuts on the member to be welded adjacent to the second welding electrode and applies a sub-pressurizing force to the member to be welded;
A movable transmission means for moving the second welding electrode from the retracted position to the pressurizing position and from the pressurizing position to the retracted position in conjunction with the movement of the first welding electrode from the retracted position to the pressurizing position and from the pressurizing position to the retracted position. And
The member to be welded is sandwiched and pressurized by the first welding electrode and the sub-pressurizing portion at the pressurizing position contacting the member to be welded and the second welding electrode at the pressurizing position, and the first pressurization is performed in the sandwiching and pressing state. A spot welding apparatus characterized in that spot welding is performed by energizing between a welding electrode and a second welding electrode.   The spot welding apparatus according to claim 1, wherein the movable transmission means is a rack and pinion mechanism.   The spot welding apparatus according to claim 1, wherein the movable transmission means is a link mechanism.

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