JP5862059B2 - Spot welding device with equalizing unit - Google Patents

Description

  The present invention belongs to a technical field related to a spot welding apparatus including an equalizing unit.

  In general, a spot welding apparatus used in an automobile production line performs welding by sandwiching a welding gun body supported by the tip of an articulated robot arm and a welding point of a workpiece (workpiece to be welded) such as a metal plate material. A fixed electrode and a movable electrode are provided. Such a spot welding apparatus uses a servo motor or the like provided on the welding gun body to position a fixed electrode and a movable electrode so as to sandwich the workpiece at the welding location of the workpiece in order to weld a plurality of locations on the automobile body. By applying a pressing force to the movable electrode, the work is sandwiched between the fixed electrode and the movable electrode to perform welding. At this time, the posture control of the welding gun body, the pressure control of the movable electrode, the workpiece support force control, and the like are performed according to the tilt state of the workpiece and the number of sets.

  Here, the welding gun body is usually supported on the tip of the articulated robot arm via an equalizing device. This equalizing device balances the weight of the welding gun body and prevents the force applied to the fixed electrode and the movable electrode so that no excessive pressure is applied to the workpiece positioned between the fixed electrode and the movable electrode when the movable electrode is pressurized. It is provided for the purpose of balancing. By this equalizing apparatus, the forces applied to the fixed electrode and the movable electrode can be made equal to generate a nugget stably, and deformation of the workpiece can be suppressed.

  By the way, most of the conventional equalizing apparatuses are operated using fluid pressure like an air cylinder or the like. In this case, pressurization and release signals are sent from the robot controller to the welding gun body and simultaneously to the equalizing cylinder. The operation of the equalizing cylinder causes the welding gun body to spring against the robot arm. Equalized.

  On the other hand, an equalizing device that does not use fluid pressure is also known (see, for example, Patent Document 1). This equalizing device is built in the welding gun body, and forms a recess in the pressure shaft that is advanced and retracted by the pressure drive unit in the welding gun body, and when the pressure shaft advances, the tip of the lever When the roller member provided on the lever falls into the recess of the pressure shaft, the lever is rotated, whereby the welding gun body is equalized with a spring force against the robot arm.

JP 2010-142847 A

  However, in the above-described conventional equalizing device using fluid pressure, an equalizing cylinder is required, and a switching valve, a speed controller (flow rate adjusting valve), a regulator, and the like must be provided in the fluid circuit. There is a problem that it becomes complicated and expensive. In addition, the spring force needs to be large enough to overcome the weight of the welding gun body, but depending on the position of the welding gun body, such a magnitude is not necessarily required. In the case of equalization, the fixed electrode may come into contact with the workpiece with a large impact force. As a result, it is difficult to adjust the spring force so as not to deform the workpiece, and there is a problem that the welding quality cannot be stabilized.

  Moreover, the equalizing device using the fluid pressure is usually provided as a dedicated device for each welding gun body, and therefore it is difficult to standardize the equalizing device, and as a result, the equalizing device There is also a problem in that the mass productivity is reduced and the manufacturing cost is increased.

  On the other hand, an equalizing device that does not use fluid pressure as in Patent Document 1 does not require an equalizing cylinder or the like, and thus can be simplified and downsized as compared with an equalizing device that uses fluid pressure.

  However, in the equalizing apparatus that does not use the fluid pressure, when the pressure gun is provided on a welding gun body having a different stroke, the position of the recess provided on the pressure shaft must be changed. Changing the axis is not easy. For this reason, the pressurizing shaft is dedicated to the welding gun body, and there is a problem that the versatility is poor.

  Further, in the equalizing device that does not use the fluid pressure, similarly to the equalizing device that uses the fluid pressure, it is difficult to adjust the spring force so as not to deform the workpiece, and the roller provided on the lever The member falls into the recess at a stroke, so that a large spring force instantaneously acts on the workpiece as an impact force.

  The present invention has been made in view of such points, and an object of the present invention is to provide a spot welding apparatus including an equalizing unit, in which the equalizing unit is configured not to use fluid pressure, and the equalizing unit is versatile. Furthermore, it is intended to alleviate the impact force applied to the work piece by the fixed electrode, suppress deformation of the work piece, and improve the welding quality as much as possible.

In order to achieve the above object, in the present invention, a welding gun body supported by a support, a fixed electrode fixed to the welding gun body via a fixing arm, the welding gun body and the fixed electrode, A spot provided with a movable electrode which is disposed so as to face the fixed electrode between and driven in the facing direction by a driving means, and an equalizing unit provided between the welding gun body and the support body For welding equipment
The above equalize unit is
An operating rod connected to the movable electrode and extending in the facing direction;
A support rod extending parallel to the actuation rod;
A support structure fixed to the support and supporting the support rod;
A movable member supported by the support rod so as to be movable in the axial direction of the support rod, and connected to the welding gun body;
A first compression coil spring provided at one axial end of the support rod and biasing the moving member to the other side of the support rod in the axial direction;
More than the first compression coil spring provided at the other end in the axial direction of the support rod and biasing the moving member toward the one side in the axial direction of the support rod with respect to the support rod. A second compression coil spring set to have a weak force;
An equalizing operation pin provided on the moving member;
An equalizing operation link lever member rotatably supported by the support structure;
With
The equalizing operation link lever member is configured such that the moving member is biased toward the other side in the axial direction of the support rod due to a difference in biasing force between the first compression coil spring and the second compression coil spring. A pressing portion that is pressed by the equalizing operation pin of the moving member; and a rotatable roller member that contacts the peripheral side surface of the operating rod by the rotational force of the equalizing operation link lever member by the pressing of the pressing portion; Have
The contact portion of the roller member on the peripheral side surface of the actuating rod has the pressing portion by the equalizing actuating pin when the actuating rod moves as the movable electrode moves to the fixed electrode side by the driving means. A cam portion for rotating the equalizing operation link lever member by pressing is formed,
The cam portion is provided on the opposite side of the first cam portion and the first cam portion with respect to the movable electrode in the axial direction of the operating rod, and operates more than the first cam portion in the radial direction of the operating rod. The second cam portion located on the side close to the shaft center of the rod, and the slope that connects the first cam portion and the second cam portion and inclines so as to approach the shaft center of the operating rod toward the side opposite to the movable electrode. It consists of a cam part,
When the actuating rod moves as the movable electrode moves toward the fixed electrode by the driving means, the roller member comes into contact with the inclined cam portion from the first cam portion of the cam portion and maintains the corresponding contact state. While the equalizing operation link lever member rotates, the moving member moves to the other side in the axial direction of the support rod, so that the fixed electrode together with the welding gun body connected to the moving member The fixed electrode is in contact with the workpiece to be positioned between the fixed electrode and the movable electrode, and the fixed electrode is in contact with the workpiece. The pressing portion is configured to be separable from the equalizing operation pin,
The distance at which the pressing portion can be separated from the equalizing operation pin is set as an equalizing amount after the fixed electrode comes into contact with the workpiece .
The configuration is as follows.

  With the above configuration, since the equalizing unit is configured not to use fluid pressure, the configuration can be simplified and the cost can be reduced. Further, since the equalizing unit is provided between the welding gun main body and the welding gun main body support body, the equalizing unit has an external configuration with respect to the welding gun main body. As a result, for welding gun bodies with different strokes of the movable electrode, the operating rod (tilt angle of the tilting cam part, position of the tilting cam part in the direction of the operating rod axis, etc.) may be changed. Easy to do. And when the weight of a welding gun main body changes, what is necessary is just to replace | exchange a 1st and 2nd compression coil spring. As a result, the main part of the equalizing unit can be made common, and the versatility of the equalizing unit can be improved.

  In addition, the moving member moves by moving the equalizing operation link lever member while the roller member contacts the inclined cam portion from the first cam portion of the cam portion and maintains the corresponding contact state, so that the moving member moves. The fixed electrode moves together with the welding gun body connected to the workpiece, and the fixed electrode comes into contact with the workpiece, so that the fixed electrode does not suddenly come into contact with the workpiece and the angle of the inclined cam portion is increased. By setting appropriately, it can be made to contact gently. As a result, the impact force applied to the workpiece by the fixed electrode can be reduced.

  Furthermore, the impact force which a fixed electrode provides with respect to a to-be-welded object can be relieve | moderated by the 1st and 2nd compression coil spring irrespective of the attitude | position of a welding gun main body. That is, when the first compression coil spring moves the moving member, for example, in the horizontal direction, the moving member is pressed with great force, but the energy can be absorbed by the second compression coil spring. As a result, even if the attitude of the welding gun body changes, the impact force remains at a small value in combination with the rotation of the equalizing operation link lever member while the roller member contacts the inclined cam portion. It can be prevented from changing greatly. Therefore, the deformation of the workpiece can be suppressed, and the welding quality can be improved.

In the above configuration, by the fixed electrode is brought into contact with the object to be welded, the pressing portion is configured to be spaced from said equalizing actuating pin, separable distance from the equalizing operation pin of the pressing portion Is set as an equalizing amount after the fixed electrode is brought into contact with the workpiece.

  That is, when the fixed electrode comes into contact with the work piece, the moving member and the equalizing operation pin cannot move to the other side in the axial direction of the support rod, while the equalizing operation link lever member further depends on the position of the second cam portion. If it can be rotated, the pressing portion can be separated from the equalizing operation pin. In this separated state, the welding gun main body is in a floating state with respect to the support, and the fixed electrode follows the position of the workpiece to be welded due to the magnitude relationship of the urging forces of the first and second compression coil springs. By this floating (that is, equalization), the force applied to the fixed electrode and the movable electrode can be made appropriate so that the workpiece is not deformed when the movable electrode is pressurized.

In another aspect of the present invention, a welding gun main body supported by a support, a fixed electrode fixed to the welding gun main body via a fixing arm, and the fixing between the welding gun main body and the fixed electrode. A spot welding apparatus provided with a movable electrode disposed so as to face an electrode and driven in a facing direction by a driving means, and an equalizing unit provided between the welding gun body and the support. ,
The above equalize unit is
An operating rod connected to the movable electrode and extending in the facing direction;
A support rod extending parallel to the actuation rod;
A support structure fixed to the support and supporting the support rod;
A movable member supported by the support rod so as to be movable in the axial direction of the support rod, and connected to the welding gun body;
A first compression coil spring provided at one axial end of the support rod and biasing the moving member to the other side of the support rod in the axial direction;
More than the first compression coil spring provided at the other end in the axial direction of the support rod and biasing the moving member toward the one side in the axial direction of the support rod with respect to the support rod. A second compression coil spring set to have a weak force;
An equalizing operation pin provided on the moving member;
An equalizing operation link lever member rotatably supported by the support structure;
With
The equalizing operation link lever member is configured such that the moving member is biased toward the other side in the axial direction of the support rod due to a difference in biasing force between the first compression coil spring and the second compression coil spring. A pressing portion that is pressed by the equalizing operation pin of the moving member; and a rotatable roller member that contacts the peripheral side surface of the operating rod by the rotational force of the equalizing operation link lever member by the pressing of the pressing portion; Have
The contact portion of the roller member on the peripheral side surface of the actuating rod has the pressing portion by the equalizing actuating pin when the actuating rod moves as the movable electrode moves to the fixed electrode side by the driving means. A cam portion for rotating the equalizing operation link lever member by pressing is formed,
The cam portion is provided on the opposite side of the first cam portion and the first cam portion with respect to the movable electrode in the axial direction of the operating rod, and operates more than the first cam portion in the radial direction of the operating rod. The second cam portion located on the side close to the shaft center of the rod, and the slope that connects the first cam portion and the second cam portion and inclines so as to approach the shaft center of the operating rod toward the side opposite to the movable electrode. Consisting of a cam part,
When the actuating rod moves as the movable electrode moves toward the fixed electrode by the driving means, the roller member comes into contact with the inclined cam portion from the first cam portion of the cam portion and maintains the corresponding contact state. While the equalizing operation link lever member rotates, the moving member moves to the other side in the axial direction of the support rod, so that the fixed electrode together with the welding gun body connected to the moving member Is moved, and the fixed electrode is configured to come into contact with an object to be welded located between the fixed electrode and the movable electrode,
The upper SL equalizing actuating link lever member, have a first and second arm portions extending from the peripheral portion of the rotating shaft radially outwardly of the peripheral portion, substantially as viewed from the rotary shaft direction L forms a shape, the tip portion of the first arm portion, the pressing portion is provided, on the distal end of the second arm portion, that has the roller members are provided.

  Thereby, the equalizing operation link lever member provided with the pressing portion and the roller member can be easily configured.

In still another aspect of the present invention, a welding gun main body supported by a support, a fixed electrode fixed to the welding gun main body via a fixing arm, and the welding gun main body and the fixed electrode between the fixed electrode. A spot welding apparatus provided with a movable electrode disposed to face a fixed electrode and driven in a facing direction by a driving means, and an equalizing unit provided between the welding gun body and the support. As
The above equalize unit is
An operating rod connected to the movable electrode and extending in the facing direction;
A support rod extending parallel to the actuation rod;
A support structure fixed to the support and supporting the support rod;
A movable member supported by the support rod so as to be movable in the axial direction of the support rod, and connected to the welding gun body;
A first compression coil spring provided at one axial end of the support rod and biasing the moving member to the other side of the support rod in the axial direction;
More than the first compression coil spring provided at the other end in the axial direction of the support rod and biasing the moving member toward the one side in the axial direction of the support rod with respect to the support rod. A second compression coil spring set to have a weak force;
An equalizing operation pin provided on the moving member;
An equalizing operation link lever member rotatably supported by the support structure;
With
The equalizing operation link lever member is configured such that the moving member is biased toward the other side in the axial direction of the support rod due to a difference in biasing force between the first compression coil spring and the second compression coil spring. A pressing portion that is pressed by the equalizing operation pin of the moving member; and a rotatable roller member that contacts the peripheral side surface of the operating rod by the rotational force of the equalizing operation link lever member by the pressing of the pressing portion; Have
The contact portion of the roller member on the peripheral side surface of the actuating rod has the pressing portion by the equalizing actuating pin when the actuating rod moves as the movable electrode moves to the fixed electrode side by the driving means. A cam portion for rotating the equalizing operation link lever member by pressing is formed,
The cam portion is provided on the opposite side of the first cam portion and the first cam portion with respect to the movable electrode in the axial direction of the operating rod, and operates more than the first cam portion in the radial direction of the operating rod. The second cam portion located on the side close to the shaft center of the rod, and the slope that connects the first cam portion and the second cam portion and inclines so as to approach the shaft center of the operating rod toward the side opposite to the movable electrode. It consists of a cam part,
When the actuating rod moves as the movable electrode moves toward the fixed electrode by the driving means, the roller member comes into contact with the inclined cam portion from the first cam portion of the cam portion and maintains the corresponding contact state. While the equalizing operation link lever member rotates, the moving member moves to the other side in the axial direction of the support rod, so that the fixed electrode together with the welding gun body connected to the moving member Is moved, and the fixed electrode is configured to come into contact with an object to be welded located between the fixed electrode and the movable electrode,
Cam portion of the upper Symbol actuating rod, the said movable electrode in said operation rod that are provided on the opposite end.

  By configuring the part including the cam part in the operating rod with a member different from the other parts, it is only necessary to change the part including the cam part with respect to the welding gun body having a different stroke of the movable electrode. Compared to the case where the entire operating rod is replaced, it becomes easier.

  As described above, according to the spot welding apparatus of the present invention, since the equalizing unit is configured not to use fluid pressure, the configuration can be simplified and the cost can be reduced. Further, since the equalizing unit is externally attached to the welding gun body, the versatility of the equalizing unit can be enhanced. Furthermore, since the equalizing operation link lever member rotates while the roller member abuts against the inclined cam portion of the cam portion, the impact force applied to the workpiece by the fixed electrode can be reduced. Further, by providing the second compression coil spring in addition to the first compression coil spring, even if the attitude of the welding gun body changes, the equalizing operation link lever member rotates while the roller member contacts the inclined cam portion. In combination with the movement, the impact force applied to the workpiece by the fixed electrode can be reduced. Therefore, it becomes possible to suppress deformation and make the pressure applied to the movable electrode and the fixed electrode uniform with respect to the work piece, thereby improving the welding quality.

In addition, floating (that is, equalization) with respect to the support of the welding gun body can make the force applied to the fixed electrode and the movable electrode appropriate so that the workpiece is not deformed when the movable electrode is pressurized, or The equalizing operation link lever member provided with the pressing portion and the roller member can be easily configured, or by configuring the portion including the cam portion in the operating rod with a member different from other portions, Only the portion including the cam portion needs to be changed with respect to the welding gun main body having a different stroke of the movable electrode, which is easier than the case where the entire operating rod is replaced.

It is a side view which shows the spot welding apparatus which concerns on embodiment of this invention. It is the side view seen from the same direction as FIG. 1 which shows an equalize unit abbreviate | omitting description of a unit attachment plate and a base plate, and fracture | ruptures and shows a one part component. FIG. 3 is a view in the direction of arrow III in FIG. 2. FIG. 4 is an IV direction arrow diagram of FIG. 2. FIG. 3 is a view corresponding to FIG. 2 showing a state in which the movable electrode is moving toward the fixed electrode. It is a figure which shows the motion of the fixed electrode at the time of welding with a spot welding apparatus, and a movable electrode.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a spot welding apparatus according to an embodiment of the present invention. The spot welding apparatus 1 includes a welding gun main body 3 that is supported at the tip of an articulated robot arm 2 as a support. The case 4 of the welding gun main body 3 accommodates a servo motor 5 as a driving means for driving a movable electrode 13 described later. With the driving force of the servo motor 5, the pressure shaft 6 protruding outward from the inside of the case 4 is driven so as to move in the axial direction. The axial movement of the pressure shaft 6 is obtained by converting the rotation of the servo motor 5 by a feed screw mechanism (not shown). The pressing shaft 6 can be directed in any direction by turning around the axis of the articulated robot arm 2, but in the present embodiment, the pressing shaft 6 moves in the vertical direction (Z in FIG. 1). In the following description, it is assumed that it is in a state (in the state of FIG. 1) that extends in the direction) and is located below the case 4.

  An equalizing unit 21 is provided between the welding gun body 3 and the robot arm 2. In this embodiment, a transformer support portion 10 that supports the welding transformer 9 is interposed between the equalizing unit 21 and the robot arm 2. The transformer support 10 (welding transformer 9) and the welding gun body 3 are located at substantially the same height.

  A fixed arm 15 having a fixed electrode 12 provided at the tip is fixed to the side surface of the case 4 of the welding gun body 3. The fixed arm 15 extends obliquely from the side surface of the case 4 toward the lower position of the transformer support 10, and then extends downward in the vertical direction at the lower side of the transformer support 10. It extends horizontally toward the underside. The fixed electrode 12 is positioned directly below the welding gun body 3.

  A movable electrode 13 is disposed between the welding gun body 3 and the fixed electrode 12 so as to face the fixed electrode 12. The movable electrode 13 is provided at the tip of the pressure shaft 6 protruding from the lower surface of the case 4 of the welding gun main body 3, and is fixed to the fixed electrode 12 and the movable electrode by the servo motor 5 via the pressure shaft 6. 13 is driven and moved in the opposite direction (up and down direction) to 13.

  The robot arm 2 positions the fixed electrode 12 and the movable electrode 13 so as to sandwich an object to be welded (for example, a metal plate material of an automobile body) and applies pressure to the movable electrode 13 to be welded. An object is sandwiched between the fixed electrode 12 and the movable electrode 13 to perform welding. At this time, as will be described later, the equalizing unit 21 operates to equalize the welding gun body 3 with respect to the robot arm 2.

  One end portion of a connecting member 16 extending in the horizontal direction is fixed to an intermediate portion in the axial direction (vertical direction) of the pressure shaft 6 so as to surround the pressure shaft 6. The lower end portion of the operating rod 17 extending in the vertical direction is fixed to the other end portion of the connecting member 16. The operating rod 17 is connected to the movable electrode 13 and extends in the facing direction. The actuating rod 17 constitutes a part of the equalizing unit 21.

  The welding transformer 9 and the fixed arm 15 are connected by a deformable shunt 18, and the welding transformer 9 and the vicinity of the other end of the coupling member 16 are connected by a deformable shunt 19, so that a welding current is obtained. The circuit for is configured.

  The equalizing unit 21 has two unit mounting plates 22 and is fixed to the transformer support 10 by the unit mounting plates 22. The two unit mounting plates 22 are arranged in a horizontal direction (in FIG. 1) perpendicular to the direction in which the transformer support 10 (welding transformer 9) and the welding gun main body 3 face each other (the X direction in FIGS. 1 to 3). They are arranged so as to face each other in the direction perpendicular to the paper surface (the Y direction shown in FIGS. 3 and 4) (see FIGS. 3 and 4).

  As shown in detail in FIGS. 2 to 4, the equalizing unit 21 has two base plates 23 that are respectively fixed to ends of the two unit mounting plates opposite to the transformer support 10. Similarly to the two unit mounting plates 22, the two base plates 23 are also arranged to face each other in the Y direction. In FIG. 2, the unit mounting plate 22 and the base plate 23 are not shown. Further, the left and right direction and the up and down direction in FIG. 2 coincide with the left and right direction (X direction) and the up and down direction (Z direction) in FIG. (Not shown in FIG. 2) is located, and the welding gun body 3 is located on the right side of FIG.

  The upper end portions and the lower end portions of the two base plates 23 are connected by an upper support member 24 and a lower support member 25, respectively. The two base plates 23, the upper support member 24, and the lower support member 25 constitute a frame-like support structure portion that supports a support rod 28 described later. The support structure portion includes the unit mounting plate 22 and the transformer support portion 10. It is fixed to the robot arm 2 via

  At both ends in the Y direction between the upper support member 24 and the lower support member 25, support rods 28 extending in the vertical direction (Z direction) in parallel with the actuating rod 17 are provided, respectively. 25. That is, screw portions 28 a are formed at both upper and lower ends of each support rod 28, and these screw portions 28 a penetrate the upper and lower support members 24 and 25, respectively, and are screwed with the nut 29. It is fixed to the upper and lower support members 24 and 25, respectively.

  A moving member 31 is supported on the support rod 28 so as to be movable in the axial direction (vertical direction) of the support rod 28. The moving member 31 has a connecting portion 31a that is rectangular when viewed from the X direction. The connecting portion 31a is connected and fixed to the side surface of the case 4 of the welding gun main body 3 on the surface of the connecting portion 31a on the welding gun main body 3 side (the right side surface in FIG. 2). Slide portions 31b extending horizontally toward the transformer support portion 10 are provided in the vicinity of the four corners of the surface on the transformer support portion 10 side (the left surface in FIG. 2) of the connecting portion 31a. The two upper and lower slide portions 31b on one side in the Y direction are supported by the support rod 28 on one side in the Y direction so as to be movable in the vertical direction, and the two upper and lower slide portions 31b on the other side in the Y direction are supported on the other side in the Y direction. The rod 28 is supported so as to be movable in the vertical direction. Thus, the welding gun main body 3 (and the fixed electrode 12) can be moved in the vertical direction along the support rod 28 via the moving member 31. One support rod 28 may be provided, and the moving member 31 may be supported by the single support rod 28 so as to be movable in the axial direction of the support rod 28.

  The support rod 28 is surrounded by a lower slide portion 31b around one side end portion (lower end portion) in the axial direction (between the lower slide portion 31b and the lower support member 25). A first compression coil spring 32 that urges the moving member 31 toward the other side (upper side) in the axial direction of the support rod 28 with respect to the support rod 28 is disposed. On the other hand, around the other end (upper end) in the axial direction of each support rod 28 (between the upper slide portion 31b and the upper support member 24), the moving member 31 is interposed via the upper slide portion 31b. The second compression coil spring 33 is set to have a biasing force weaker than that of the first compression coil spring 32, which biases the support rod 28 toward the one side (lower side) in the axial direction of the support rod 28. It is arranged. The first and second compression coil springs 32 and 33 may be disposed one by one for each support rod 28, or may be disposed in plurality (in this case, the plurality of compression coil springs are concentric). Disposed).

  Since the biasing force of the second compression coil spring 33 is weaker than the biasing force of the first compression coil spring 33, the moving member 31 is supported by the difference in biasing force between the first compression coil spring 32 and the second compression coil spring 33. The rod 28 is biased toward the other side (upper side) in the axial direction. However, as will be described later, when the equalizing unit 21 is not in operation (before equalization), it cannot be moved upward from the position shown in FIG.

  The total biasing force of the moving member 31 by the first compression coil spring 32 is a predetermined amount (moving) than the weight of the welding gun main body 3 (including the weights of the fixed electrode 12, the movable electrode 13, the pressure shaft, the moving member 31, etc.). It becomes larger as the member 31 rises). This predetermined amount is set to a value capable of pushing up the moving member 31 in consideration of the urging force of the second compression coil spring 33.

  A pin support portion 31c is formed to project to the transformer support portion 10 side at the lower portion of the central portion in the Y direction of the surface on the transformer support portion 10 side of the connecting portion 31a of the moving member 31. An equalizing operation pin 35 passes through the pin support portion 31c in the vertical direction. A screw portion 35a is formed on the outer peripheral surface of the equalizing operation pin 35 to be screwed with a nut 36 fixed to the lower surface of the pin support portion 31c. By this screwing, the equalizing operation pin 35 can be moved in the vertical direction. It is supported by the pin support part 31c. An engagement recess 35b that engages with a tool for rotating the equalizing operation pin 35 is formed at the lower end portion of the equalizing operation pin 35, and the equalizing operation pin 35 is rotated by the tool, thereby equalizing. The vertical position of the operating pin 35 with respect to the pin support portion 31c can be adjusted.

  A link lever member support portion 25a is formed on the upper surface of the lower support member 25 so as to protrude upward in the center in the Y direction. The link lever member support portion 25a is located on the transformer support portion 10 side with respect to the pin support portion 31c.

  An equalizing operation link lever member 39 (hereinafter referred to as a link lever member 39) is supported on the upper end portion of the link lever member support portion 25a via a support pin 38 extending in the Y direction. The link lever member 39 is rotatable around the support pin 38 and is supported rotatably on the support structure portion. The support pin 38 corresponds to the rotation shaft of the link lever member 39.

  The link lever member 39 includes first and second arm portions 39a and 39b extending from the periphery of the support pin 38 (rotating shaft) to the radially outer side of the periphery, and the axial direction of the support pin 38 It is substantially L-shaped when viewed from the top. The first arm portion 39 a extends from the peripheral portion toward the welding gun main body 3, and the distal end portion thereof is located above the equalizing operation pin 35. The second arm portion 39 b extends upward from the peripheral portion, and the tip portion thereof is located in the vicinity of the upper support member 24. The link lever member support portion 25a, the link lever member 39, and the equalizing operation pin 35 are located at the same position in the Y direction.

  The moving member 31 is urged to the upper side of the support rod 28 due to the difference in urging force between the first compression coil spring 32 and the second compression coil spring 33 at the lower portion of the distal end portion of the first arm portion 39a. A pressing portion 39 c that is pressed by the equalizing operation pin 35 of the moving member 31 is provided. Further, a roller member 40 that abuts on the peripheral side surface of the operating rod 17 is provided at the distal end portion of the second arm portion 39b by the turning force of the link lever member 39 by the pressing of the pressing portion 39c. The roller member 40 is rotatable around a rotation shaft 41 extending in the Y direction.

  The actuating rod 17 extends in the vertical direction at the same position as the link lever member 39 and the equalize actuating pin 35 in the Y direction in the vicinity of the link lever member supporting portion 25a and the link lever member 39 in the Y direction. Yes. The actuating rod 17 is composed of two upper and lower members, and includes a first member 17a constituting the upper end portion of the actuating rod 17 and a second member 17b constituting the other part (in FIG. 4, Only a part of the first member 17a is shown). The first member 17a and the second member 17b are coupled to each other in the vicinity of the support pin 38. As described above, the lower end portion of the second member 17b is fixed to the other end portion of the connecting member 16 whose one end portion is fixed to the pressure shaft 6. The upper end portion (first member 17a) of the actuating rod 17 is inserted into an insertion hole 24b (a hole penetrating vertically) of the actuating rod support portion 24a provided in the center portion in the Y direction of the upper support member 24, so that the first The upper end of the member 17a is located above the upper surface of the operating rod support 24a.

  At the contact portion of the roller member 40 on the circumferential side surface of the operating rod 17 (the portion of the first member 17a on the side of the welding gun body 3), the servo motor 5 moves the movable electrode 13 toward the fixed electrode 12 side. A cam portion 17c is formed for rotating the link lever member 39 by the pressing of the pressing portion 39c by the equalizing operation pin 35 when the operating rod 17 is moved. The cam portion 17c is provided at the end of the operating rod 17 opposite to the movable electrode 13. The cam portion 17 c is provided on the opposite side (upper side) from the movable electrode 13 with respect to the first cam portion 17 d and the first cam portion 17 d in the axial direction of the operating rod 17, and the first cam portion 17 c in the radial direction of the operating rod 17. The cam portion 17d includes a second cam portion 17e positioned closer to the axis of the operating rod 17 and an inclined cam portion 17f that connects the first cam portion 17d and the second cam portion 17e. The first and second cam portions 17d, 17e extend in a direction (vertical direction) along the axis of the operating rod 17, and are formed in a flat shape. The inclined cam portion 17f is inclined so as to approach the axis of the operating rod 17 toward the side opposite to the movable electrode 13 (upper side).

  In a state before equalization, the roller member 40 is in contact with the first cam portion 17d. At this time, the pressing portion 39c of the link lever member 39 is pressed upward by the equalizing operation pin 35 of the moving member 31 urged upward as described above, so that the link lever member 39 has the support pin 38 of Although a force to rotate counterclockwise in FIG. 2 acts, the link lever member 39 rotates further from the state of FIG. 2 because the roller member 40 is in contact with the first cam portion 17d. I can't move. Further, the moving member 31 (equalizing operation pin 35) cannot move upward from the state of FIG. At this time, by adjusting the vertical position of the equalizing operation pin 35 with respect to the pin support portion 31c, the height position of the welding gun body 3 relative to the robot arm, that is, the height position of the fixed electrode 12 before equalization can be adjusted. it can.

  The operating rod 17 (first member 17a) is pressed toward the transformer support 10 by the roller member 40, but the portion inserted into the insertion hole 24b of the operation rod support 24a is the inside of the insertion hole 24b. Since it contacts the peripheral surface, the upper end of the actuating rod 17 does not tilt toward the transformer support 10 with respect to the lower end.

  When the movable electrode 13 is moved to the fixed electrode 12 side (downward) by the servo motor 5, the actuating rod 17 is also moved downward. Thereby, as shown in FIG. 5, the part corresponding to the roller member 40 of the operating rod 17 changes from the first cam part 17d of the cam part 17c to the inclined cam part 17f. Since the pressing portion 39c of the link lever member 39 is pressed upward by the equalizing operation pin 35 and is going to rotate counterclockwise in FIG. 2, the roller member 40 is the first cam portion 17d of the cam portion 17c. Will contact the inclined cam portion 17f. The inclination angle of the inclined cam portion 17f with respect to the axis of the operating rod 17 is gentle, and the link lever member 39 is rotated while the roller member 40 is in contact with the inclined cam portion 17f. When the link lever member 39 rotates while maintaining this contact state, the moving member 31 (equalizing operation pin 35) moves to the other side (upper side) in the axial direction of the support rod 28. As a result, the fixed electrode 12 moves upward together with the welding gun main body 3 connected and fixed to the moving member 31, and the fixed electrode 12 comes into contact with an object to be welded located between the fixed electrode 12 and the movable electrode 13. It is like that.

  When the fixed electrode 12 comes into contact with the work piece, the moving member 31 (equalization operation pin 35) can no longer be raised, so that the pressing portion 39c can be separated from the equalization operation pin 35. That is, when the movable electrode 13 is in contact with the workpiece, the portion corresponding to the roller member 40 of the actuating rod 17 is the second cam portion 17e of the cam portion 17c, and the link lever member 39 is a roller member. Further rotation can be performed until 40 comes into contact with the second cam portion 17e. As a result, the link lever member 39 can freely rotate between a rotation position where the pressing portion 39c contacts the equalizing operation pin 35 and a rotation position where the roller member 40 contacts the second cam portion 17e. Become. When the link lever member 39 is positioned at the rotational position where the roller member 40 abuts against the second cam portion 17e, the separation distance of the pressing portion 39c from the equalizing operation pin 35 is the contact distance of the fixed electrode 12 against the workpiece. It is set as the equalize amount after contact. In this embodiment, the equalization amount is 5 mm (note that the equalization amount until the fixed electrode 12 comes into contact with the workpiece is also 5 mm, and the total equalization amount is 10 mm). At this time, the welding gun body 3 is in a floating state with respect to the robot arm, and the fixed electrode 12 follows the position of the workpiece to be welded due to the magnitude of the urging force of the first and second compression coil springs 32 and 33. . In this way, the welding gun body 3 is equalized with respect to the robot arm 2.

  Next, the operation | movement at the time of welding to a to-be-welded object with the said spot welding apparatus 1 is demonstrated with reference to FIG. In this description, it is assumed that the workpieces are the upper and lower metal plate members 51 and 52 that are overlapped with each other and extend in the horizontal direction, and predetermined portions of the metal plate members 51 and 52 are spot-welded.

  First, as shown in FIG. 6A, the robot arm 2 is driven so that both metal plate members 51 and 52 are positioned between the fixed electrode 12 and the movable electrode 13, and the fixed electrode 12 is The lower metal plate 52 is positioned below the portion to be welded. At this time, the distance between the upper end of the fixed electrode 12 and the lower surface of the lower metal plate 52 is set to a predetermined value (5 mm in this embodiment). This predetermined value is the amount of equalization until the fixed electrode 12 comes into contact with the workpiece. The pressure shaft 6 extends in the vertical direction and is located under the case 4 of the welding gun main body 3 (state shown in FIG. 1).

  Subsequently, the movable electrode 13 is moved downward by the servo motor 5. As the movable electrode 13 moves, the operating rod 17 also moves downward, so that the link lever member 39 is rotated counterclockwise in FIG. 2 by the inclined cam portion 17f of the cam portion 17c of the operating rod 17. As a result, the moving member 31 (equalizing operation pin 35) rises. With this rise, the fixed electrode 12 moves upward together with the welding gun main body 3, and the fixed electrode 12 contacts the lower metal plate 52 (see FIG. 6B). At this time, the link lever member 39 rotates in a state where the roller member 40 is in contact with the inclined cam portion 17f, so that the fixed electrode 12 is not suddenly contacted with the lower metal plate material 52, and is gently Abut. As a result, the impact force applied to the workpiece by the fixed electrode 12 can be reduced. In addition, when the moving member 31 and the welding gun main body 3 move in the horizontal direction, for example, the moving member 31 is vigorously pressed by the first compression coil spring 32, but the energy is absorbed by the second compression coil spring 33. Can be absorbed. Therefore, even if the attitude of the welding gun main body 3 changes, the impact force can be kept small and not greatly changed.

  The movable electrode 13 continuously moves downward and eventually comes into contact with the upper metal plate 51 (see FIG. 6C). At this time, the roller member 40 is already in contact with the second cam portion 17e. As a result, the link lever member 39 freely rotates between the rotation position where the pressing portion 39c contacts the equalizing operation pin 35 and the rotation position where the roller member 40 contacts the second cam portion 17e. Thus, the equalizing amount after contact with the lower metal plate 52 of the fixed electrode 12 is ensured to be 5 mm. At this time, the welding gun main body 3 is in a floating state (that is, in an equalized state), and the fixed electrode 12 is the lower metal plate member 52 due to the urging force of the first and second compression coil springs 32 and 33. Follow the position. By this floating, when the movable electrode 13 is pressed, the force applied to the fixed electrode 12 and the movable electrode 13 can be made appropriate so that the upper and lower metal plates 51 and 52 are not deformed.

  After the movable electrode 13 abuts on the upper metal plate 51, the upper and lower metal plates 51, 52 are held in the state where the upper and lower metal plates 51, 52 are sandwiched between the fixed electrode 12 and the movable electrode 13. Spot welding is performed on the spot. In this way, spot welding with good welding quality can be performed.

  After welding, the movable electrode 13 is raised and returned to the original position. As a result, the operating rod 17 also moves upward. At this time, the roller member 40 is pressed by the inclined cam portion 17f, and the link lever member 39 rotates clockwise in FIG. As a result, the equalizing operation pin 35 is pushed downward by the pressing portion 39c, and the moving member 31 returns to the position before equalization. As a result, the welding gun main body 3 and the fixed electrode 12 are also returned to the positions before the equalization, and the state shown in FIG. Next, the robot arm 2 is driven to move the fixed electrode 12 to the lower side of the next portion to be welded, and the above operation is repeated.

  Therefore, in this embodiment, since the operation of the equalizing unit 21 is configured not to use electric driving force or fluid pressure, the configuration can be simplified and the cost can be reduced. Further, since the equalizing unit 21 is externally attached to the welding gun main body 3, the versatility of the equalizing unit 21 can be enhanced. That is, for the welding gun main body 3 having a different stroke of the movable electrode 13, the inclination angle of the inclined cam portion 17f in the cam portion 17c, the axial position of the operating rod 17 of the inclined cam portion 17f, etc. may be changed. In particular, in the present embodiment, since the operating rod 17 includes the first member 17a including the cam portion 17c and the other second member 17b, it is only necessary to replace the first member 17a. When the weight of the welding gun main body 3 changes, the first and second compression coil springs 32 and 33 may be replaced. Further, since the link lever member 39 rotates while the roller member 40 contacts the inclined cam portion 17f of the cam portion 17c, the impact force applied to the workpiece by the fixed electrode 12 can be reduced. Further, by providing the second compression coil spring 33 in addition to the first compression coil spring 32, the link lever member 40 is in contact with the inclined cam portion 17f even when the posture of the welding gun body 3 changes. Combined with the rotation of 39, the impact force applied to the workpiece by the fixed electrode 12 can be reduced. Therefore, the deformation of the workpiece can be suppressed, and the welding quality can be improved.

  The present invention is not limited to the embodiment described above, and can be substituted without departing from the spirit of the claims.

  For example, in the above embodiment, the welding gun body 3 is supported by the robot arm 2 as a support, but the support is not limited to the robot arm 2.

  The above-described embodiments are merely examples, and the scope of the present invention should not be interpreted in a limited manner. The scope of the present invention is defined by the scope of the claims, and all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

  The present invention is useful for a spot welding apparatus including an equalizing unit.

1 Spot welding equipment 2 Robot arm (support)
3 Welding gun body 4 Servo motor (drive means)
12 fixed electrode 13 movable electrode 15 fixed arm 17 actuating rod 17c cam part 17d first cam part 17e second cam part 17f inclined cam part 21 equalize unit 23 base plate (support structure part)
24 Upper support member (support structure part)
25 Lower support member (support structure)
28 support rod 31 moving member 32 first compression coil spring 33 second compression coil spring 35 equalizing operation pin 39 equalizing operation link lever member 39a first arm portion 39b second arm portion 39c pressing portion 40 roller member 51 upper metal plate ( Work piece)
52 Lower metal plate (workpiece)

Claims (3)

A welding gun body supported by a support, a fixed electrode fixed to the welding gun body via a fixed arm, and disposed between the welding gun body and the fixed electrode so as to face the fixed electrode A spot welding apparatus comprising a movable electrode driven in the opposite direction by a driving means, and an equalizing unit provided between the welding gun body and the support,
The above equalize unit is
An operating rod connected to the movable electrode and extending in the facing direction;
A support rod extending parallel to the actuation rod;
A support structure fixed to the support and supporting the support rod;
A movable member supported by the support rod so as to be movable in the axial direction of the support rod, and connected to the welding gun body;
A first compression coil spring provided at one axial end of the support rod and biasing the moving member to the other side of the support rod in the axial direction;
More than the first compression coil spring provided at the other end in the axial direction of the support rod and biasing the moving member toward the one side in the axial direction of the support rod with respect to the support rod. A second compression coil spring set to have a weak force;
An equalizing operation pin provided on the moving member;
An equalizing operation link lever member rotatably supported by the support structure;
With
The equalizing operation link lever member is configured such that the moving member is biased toward the other side in the axial direction of the support rod due to a difference in biasing force between the first compression coil spring and the second compression coil spring. A pressing portion that is pressed by the equalizing operation pin of the moving member; and a rotatable roller member that contacts the peripheral side surface of the operating rod by the rotational force of the equalizing operation link lever member by the pressing of the pressing portion; Have
The contact portion of the roller member on the peripheral side surface of the actuating rod has the pressing portion by the equalizing actuating pin when the actuating rod moves as the movable electrode moves to the fixed electrode side by the driving means. A cam portion for rotating the equalizing operation link lever member by pressing is formed,
The cam portion is provided on the opposite side of the first cam portion and the first cam portion with respect to the movable electrode in the axial direction of the operating rod, and operates more than the first cam portion in the radial direction of the operating rod. The second cam portion located on the side close to the shaft center of the rod, and the slope that connects the first cam portion and the second cam portion and inclines so as to approach the shaft center of the operating rod toward the side opposite to the movable electrode. It consists of a cam part,
When the actuating rod moves as the movable electrode moves toward the fixed electrode by the driving means, the roller member comes into contact with the inclined cam portion from the first cam portion of the cam portion and maintains the corresponding contact state. While the equalizing operation link lever member rotates, the moving member moves to the other side in the axial direction of the support rod, so that the fixed electrode together with the welding gun body connected to the moving member The fixed electrode is in contact with the workpiece to be positioned between the fixed electrode and the movable electrode, and the fixed electrode is in contact with the workpiece. The pressing portion is configured to be separable from the equalizing operation pin,
A spot welding apparatus provided with an equalizing unit, characterized in that a distance by which the pressing portion can be separated from the equalizing operation pin is set as an equalizing amount after contact of the fixed electrode with the workpiece. A welding gun body supported by a support, a fixed electrode fixed to the welding gun body via a fixed arm, and disposed between the welding gun body and the fixed electrode so as to face the fixed electrode A spot welding apparatus comprising a movable electrode driven in the opposite direction by a driving means, and an equalizing unit provided between the welding gun body and the support,
The above equalize unit is
An operating rod connected to the movable electrode and extending in the facing direction;
A support rod extending parallel to the actuation rod;
A support structure fixed to the support and supporting the support rod;
A movable member supported by the support rod so as to be movable in the axial direction of the support rod, and connected to the welding gun body;
A first compression coil spring provided at one axial end of the support rod and biasing the moving member to the other side of the support rod in the axial direction;
More than the first compression coil spring provided at the other end in the axial direction of the support rod and biasing the moving member toward the one side in the axial direction of the support rod with respect to the support rod. A second compression coil spring set to have a weak force;
An equalizing operation pin provided on the moving member;
An equalizing operation link lever member rotatably supported by the support structure;
With
The equalizing operation link lever member is configured such that the moving member is biased toward the other side in the axial direction of the support rod due to a difference in biasing force between the first compression coil spring and the second compression coil spring. A pressing portion that is pressed by the equalizing operation pin of the moving member; and a rotatable roller member that contacts the peripheral side surface of the operating rod by the rotational force of the equalizing operation link lever member by the pressing of the pressing portion; Have
The contact portion of the roller member on the peripheral side surface of the actuating rod has the pressing portion by the equalizing actuating pin when the actuating rod moves as the movable electrode moves to the fixed electrode side by the driving means. A cam portion for rotating the equalizing operation link lever member by pressing is formed,
The cam portion is provided on the opposite side of the first cam portion and the first cam portion with respect to the movable electrode in the axial direction of the operating rod, and operates more than the first cam portion in the radial direction of the operating rod. The second cam portion located on the side close to the shaft center of the rod, and the slope that connects the first cam portion and the second cam portion and inclines so as to approach the shaft center of the operating rod toward the side opposite to the movable electrode. Consisting of a cam part,
When the actuating rod moves as the movable electrode moves toward the fixed electrode by the driving means, the roller member comes into contact with the inclined cam portion from the first cam portion of the cam portion and maintains the corresponding contact state. While the equalizing operation link lever member rotates, the moving member moves to the other side in the axial direction of the support rod, so that the fixed electrode together with the welding gun body connected to the moving member Is moved, and the fixed electrode is configured to come into contact with an object to be welded located between the fixed electrode and the movable electrode,
The equalizing operation link lever member has first and second arms extending from the periphery of the rotating shaft to the outer side in the radial direction of the rotating portion, and is substantially L-shaped when viewed from the rotating shaft direction. Shape
The pressing part is provided at the tip of the first arm part,
A spot welding apparatus comprising an equalizing unit, wherein the roller member is provided at a tip of the second arm portion. A welding gun body supported by a support, a fixed electrode fixed to the welding gun body via a fixed arm, and disposed between the welding gun body and the fixed electrode so as to face the fixed electrode A spot welding apparatus comprising a movable electrode driven in the opposite direction by a driving means, and an equalizing unit provided between the welding gun body and the support,
The above equalize unit is
An operating rod connected to the movable electrode and extending in the facing direction;
A support rod extending parallel to the actuation rod;
A support structure fixed to the support and supporting the support rod;
A movable member supported by the support rod so as to be movable in the axial direction of the support rod, and connected to the welding gun body;
A first compression coil spring provided at one axial end of the support rod and biasing the moving member to the other side of the support rod in the axial direction;
More than the first compression coil spring provided at the other end in the axial direction of the support rod and biasing the moving member toward the one side in the axial direction of the support rod with respect to the support rod. A second compression coil spring set to have a weak force;
An equalizing operation pin provided on the moving member;
An equalizing operation link lever member rotatably supported by the support structure;
With
The equalizing operation link lever member is configured such that the moving member is biased toward the other side in the axial direction of the support rod due to a difference in biasing force between the first compression coil spring and the second compression coil spring. A pressing portion that is pressed by the equalizing operation pin of the moving member; and a rotatable roller member that contacts the peripheral side surface of the operating rod by the rotational force of the equalizing operation link lever member by the pressing of the pressing portion; Have
The contact portion of the roller member on the peripheral side surface of the actuating rod has the pressing portion by the equalizing actuating pin when the actuating rod moves as the movable electrode moves to the fixed electrode side by the driving means. A cam portion for rotating the equalizing operation link lever member by pressing is formed,
The cam portion is provided on the opposite side of the first cam portion and the first cam portion with respect to the movable electrode in the axial direction of the operating rod, and operates more than the first cam portion in the radial direction of the operating rod. The second cam portion located on the side close to the shaft center of the rod, and the slope that connects the first cam portion and the second cam portion and inclines so as to approach the shaft center of the operating rod toward the side opposite to the movable electrode. It consists of a cam part,
When the actuating rod moves as the movable electrode moves toward the fixed electrode by the driving means, the roller member comes into contact with the inclined cam portion from the first cam portion of the cam portion and maintains the corresponding contact state. While the equalizing operation link lever member rotates, the moving member moves to the other side in the axial direction of the support rod, so that the fixed electrode together with the welding gun body connected to the moving member Is moved, and the fixed electrode is configured to come into contact with an object to be welded located between the fixed electrode and the movable electrode,
A spot welding apparatus comprising an equalizing unit , wherein the cam portion of the operating rod is provided at an end of the operating rod opposite to the movable electrode.

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