JP2008149329A - Electric resistance spot welding machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric resistance spot welding machine in which a plurality of electrodes can be automatically switched and used. <P>SOLUTION: In each of the first and the second electrode holder of the electric resistance spot welding machine, a plurality of electrodes 10 are installed with a specific angle apart on the outer periphery. The electrodes are designed to be rotatable intermittently at the prescribed angle by a rotating means 47 so that one each electrode of the two electrode holders is stopped oppositely facing to each other at a welding position. By rotating at least one of the first or second electrode holders by the rotating means 47, an arbitrary electrode installed in the first and second electrode holders are selectively placed opposite to each other, and the welded object is held between these electrodes, to weld the welded object. The rotating means 47 is composed of a driving means for rotating the first holder, a first pinion gear 49 for transmitting the torque of the electrode holder, a second pinion gear 69 for rotating the second electrode holder, and a rack gear 80 that are engaged with the first and second pinion gears 49, 69 and that are arranged freely attachably/detachably with the pinion gears. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an improvement in an electric resistance spot welder.

  Conventionally, as shown in Non-Patent Document 1, an electric resistance spot welder is one in which a workpiece is sandwiched between an upper electrode and a lower electrode, pressurized and energized, and the workpiece is melted and welded by electric resistance heat flowing through the workpiece. It is widely used when welding automobile white bodies and the like. The electrodes used in the electric resistance spot welder need to be properly used according to the shape and welding conditions of the work piece. If the shape and welding conditions of the work piece change, the electric resistance spot corresponding to the electrode changes accordingly. It is necessary to prepare a welder.

In addition, when welding workpieces of high-mix low-volume production with an electric resistance spot welder, it is necessary to replace the electrodes when the shape of the workpiece and welding conditions change. Conventionally, in such a case, the electrode is removed from the electric resistance spot welder and another electrode suitable for the welding conditions is attached. Especially when the workpiece changes frequently, it takes a lot of labor and time to replace the electrode. There is a problem that productivity does not increase.
Chuo Seisakusho Co., Ltd. Electric resistance spot welder catalog

  An electrical resistance spot welder capable of automatically switching and using a plurality of electrodes is provided.

  The present invention, which has been made to solve the above-described problems, is an electric resistance spot welding in which electrodes are attached to first and second electrode holders that are detachably opposed to each other, and an object to be welded is welded between the opposed electrodes. In the machine, both the first and second electrode holders described above are assumed that a plurality of electrodes are attached to the outer periphery at a certain angle, and one of the electrodes of both electrode holders is stopped at the welding position. As described above, the rotation means can rotate intermittently by a predetermined angle. By rotating at least one of the first electrode holder and the second electrode holder by the rotation means, the first electrode holder can be rotated. Arbitrary electrodes attached to the first and second electrode holders are selected to face each other, and the workpiece is sandwiched between these electrodes, and the workpiece is welded. It is characterized in.

  It is preferable that the first electrode holder and the second electrode holder are rotated by a single rotating means by the driving means that transmits the rotational force of the rotating means.

  The rotating means rotates the first electrode holder, the driving means transmits a first pinion gear that transmits the rotational force of the first electrode holder, and the second pinion gear rotates the second electrode holder; It is preferable that the first and second pinion gears engage with the first pinion gear and the second pinion gear, and the rack gear is disposed so as to be detachable from at least one of the first and second pinion gears.

  Further, when the rotating means rotates the first electrode holder, the rack gear is separated from at least one of the first pinion gear and the second pinion gear to release the engagement, so that only the first rotating holder is used. Is preferably rotatable.

  Further, it is preferable that the first pinion gear is disposed coaxially with the first electrode holder, and the second pinion gear is disposed coaxially with the second electrode holder.

  The rotating means is preferably either an air cylinder or a hydraulic cylinder.

  Further, it is preferable to provide a clutch mechanism that transmits and interrupts the rotational force of the rotating means.

  In addition, the clutch mechanism includes a plate portion that transmits the rotational force of the rotating means through the rotation shaft portion that transmits the rotational force to the first electrode holder, and the slide mechanism that is slidable in the axial direction of the rotation shaft portion. It is preferable to have a clutch pin that is housed inside the plate portion and is swinged out and engaged in an engagement hole that is recessed at a certain angle on the outer peripheral surface of the rotating shaft portion.

  In addition, a connection recess for receiving the tip of the contact through which the welding current flows is formed at a certain angle on the outer peripheral surface of the rotating shaft portion that transmits the rotational force of the rotating means to the electrode holder, and the tip of the contact is It is preferable that the contact is configured so as to be detachable from the connection recess.

  Both the first and second electrode holders are rotated so that one of the electrodes of both electrode holders is opposed to each other at the welding position, assuming that a plurality of electrodes are attached to the outer periphery at a certain angle. The first and second electrode holders can be rotated intermittently by a predetermined angle by rotating at least one of the first electrode holder and the second electrode holder by the rotating means. Arbitrary electrodes attached to the electrode holder are selected to face each other, and the workpiece is sandwiched between these electrodes so that the workpiece is welded. It is possible to provide an electric resistance spot welder that can be automatically switched and used.

  When the electrical resistance spot welder of the present invention is used in the production line, a plurality of electrodes suitable for the work piece can be automatically switched and used, so a welder for each work piece is installed. There is no need to install a handling device for transporting workpieces to the next welding machine that has been welded by a welding machine, or a stand for temporary placement and buffering for transportation to the next welding machine. An installation place is not required, and the production line can be simplified without being lengthened.

  Alternatively, when the electric resistance spot welding machine according to the present invention is used when welding workpieces of high-mix low-volume production, a plurality of electrodes suitable for the workpiece can be automatically switched and used. Therefore, it is possible to improve productivity without requiring labor and time for electrode replacement.

  Further, when the first electrode holder and the second electrode holder are rotated by a single rotating means by the driving means that transmits the rotational force of the rotating means, there is no need to provide a rotating means for each electrode holder. It becomes possible to reduce the cost.

  The rotating means rotates the first electrode holder, the driving means transmits a first pinion gear that transmits the rotational force of the first electrode holder, a second pinion gear that rotates the second electrode holder, and the first When constituted by a rack gear that engages with one pinion gear and a second pinion gear and is disposed so as to be detachable from at least one of the first pinion gear and the second pinion gear, It becomes possible to rotate the second electrode holder. Moreover, by comprising in this way, it becomes possible to rotate a 1st electrode holder and a 2nd electrode holder synchronously.

  Further, when the rotating means rotates the first electrode holder, the rack gear is separated from at least one of the first pinion gear and the second pinion gear to release the engagement, so that only the first rotating holder is used. Can be rotated in two patterns, that is, the operation of rotating only the first electrode holder and the operation of rotating both the first electrode holder and the second electrode holder. It is possible to weld by combining any electrode attached to the electrode holder and the second electrode holder.

  Further, when the first pinion gear is disposed coaxially with the first electrode holder and the second pinion gear is disposed coaxially with the second electrode holder, the driving means can be configured with a simple structure. Is possible.

  In addition, when air cylinders or hydraulic cylinders are used as the rotating means, the electrodes attached to the electrode holder at a certain angle can be reliably rotated at the certain angle by full stroke of these cylinders. It becomes possible.

  If a clutch mechanism for transmitting / cutting off the rotational force of the rotating means is provided, the electrode holder can be rotated intermittently by a predetermined angle by repeating the operation of transmitting / cutting off the rotating force of the rotating means by this clutch mechanism. It becomes possible. In addition, when the rotating means is operated with the clutch mechanism in a state where the rotational force of the rotating means is transmitted, the two electrodes attached to the first electrode holder are quickly and sequentially moved to the second electrode holder. It becomes possible to make it oppose to the electrode attached to, and it becomes possible to improve productivity.

  The clutch mechanism has a rotating shaft portion that transmits a rotational force to the first electrode holder, and a plate portion that transmits the rotational force of the rotating means, and a slideable in the axial direction of the rotating shaft portion. When the clutch pin is housed inside the plate portion and is engaged with the engagement hole formed in a recess formed on the outer peripheral surface of the rotating shaft portion at a certain angle, the rotational force of the rotating means is reliably transferred to the electrode. It can be transmitted to the holder.

  In addition, a connection recess for receiving the tip of the contact through which the welding current flows is formed at a certain angle on the outer peripheral surface of the rotating shaft portion that transmits the rotational force of the rotating means to the electrode holder, and the tip of the contact is If the contact is configured so as to be detachable from the connection recess, the electrode holder can be rotated by the rotating means by separating the tip of the contact from the connection recess, and the electrode holder can be rotated by the rotating means. After that, if the tip of the contact is received and connected to the connection recess, it is possible to reliably supply a current for electric resistance welding to the electrode holder. In addition, when the tip of the contact is received in the connection recess, the rotation shaft portion can be positioned, and the rotation shaft portion can be prevented from rotating.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a side view of an electric resistance spot welder showing an embodiment of the present invention, and FIG. 2 is a front view thereof. Reference numeral 1 denotes an apparatus main body of an electric resistance spot welder, in which a transformer and the like for supplying current to the electrodes are provided. The device main body 1 has a lower arm portion 2 and an upper arm portion 3 that are arranged to face each other in the vertical direction and project from the front side of the device.

  A lower electrode unit 4 is attached to the tip of the lower arm 2. A pressurizing mechanism 5 is provided at the tip of the upper arm 3, and an upper electrode unit 6 is attached to a lower end 5 a of the pressurizing mechanism 5. The upper electrode unit 6 is moved up and down by the pressurizing mechanism 5 so that the lower electrode unit 4 and the upper electrode unit 6 facing each other can be separated from each other.

  FIG. 3 shows a side view of the main part, and FIG. 4 shows a rear view of the main part. The lower electrode unit 4 will be described below. The lower electrode unit 4 mainly includes a lower electrode unit 40 main body, a rotating shaft portion 41, and a first electrode holder 42. The lower electrode unit 40 has a box shape and is attached to the tip of the lower arm 2. The rotating shaft portion 41 has a substantially cylindrical shape, and is rotatably supported by the lower electrode unit main body 41.

  The first electrode holder 42 has a flat and substantially cylindrical shape, and is attached to the front end of the rotary shaft portion 41 on the front side of the apparatus so as to be coaxial with the rotary shaft of the rotary shaft portion 41. Note that the first electrode holder 42 is electrically connected to the rotary shaft portion 41. A plurality of electrodes 10 are attached to the outer periphery of the first electrode holder 42 at a certain angle. In the present embodiment, the four electrodes 10 are attached to the first electrode holder 42 with an interval of 90 degrees. The number of electrodes attached to the electrode holder 42 is not limited to four, and may be two, three, or four or more. The cooling water is conducted through the rotary shaft portion 41 and the first electrode holder 42 to cool the electrode 10.

  The tip shape of the electrode 10 attached to the first electrode holder 42 is any of a planar shape, a spherical shape, a dome shape, a truncated cone shape, a truncated cone spherical shape 10b, an eccentric shape, an eccentric spherical shape, a point shape, and the like. Alternatively, different types of electrodes 10 can be attached to the first electrode holder 42.

  Further, the electrode 10 attached to the first electrode holder 42 may be a nut driving lower electrode 10c as shown in FIG. The nut driving lower electrode 10c is composed of a substantially cylindrical base electrode 10d and a center pin 10e accommodated in the base electrode 10d so as to be extendable and contractible. The center pin 10e is urged to the outside in the axial direction of the base electrode 10d, and the tip protrudes from the base electrode 10d. The outer diameter of the center pin 10e is slightly larger than the inner diameter of the screw hole of the nut attached to the member to be welded, and has a size corresponding to the inner diameter of the screw hole of the nut.

  When the nut driving lower electrode 10c is attached to the first electrode holder 42, compressed air is supplied to the base electrode 10d of the nut driving lower electrode 10c at the front portion of the first electrode holder 42. An air jacket 51 is provided. An air pipe 52 supplies compressed air to the air jacket 51.

  When the nut is welded to the workpiece, the nut is set on the center pin 10e, and is energized and welded while being pressurized with a nut driving upper electrode 10f attached to the second electrode holder 6 described later. At this time, compressed air is blown into the base electrode 10d and air is circulated between the base electrode 10d and the center pin 10e, thereby preventing spatter from entering the base electrode 10d, and the base electrode 10d and The center pin 10e is cooled. Note that the center pin 10e may be urged outward in the axial direction of the base electrode 10d with compressed air. In this case, when the center pin 10e is pressed when being pressed with the upper electrode for driving the nut. At the same time, the compressed air flows between the base electrode 10d and the center pin 10e.

  On the outer peripheral surface of the rotating shaft portion 41, connection concave portions 41a that are recessed in a substantially conical shape are formed with a predetermined interval. The connection recesses 41 a are recessed in the outer peripheral surface of the rotating shaft portion 41 in the same number as the number of electrodes 10 attached to the first electrode holder 42.

  Reference numeral 43 denotes a contact, a tip 43a of which has a substantially conical shape, and a base 43b of which has a substantially cylindrical shape. The contact 43 is disposed on the lower side of the rotating shaft portion 41, and is moved up and down by an air cylinder 44 so that the tip 43a of the contact 43 can be separated from and connected to the connection recess 41a. The tip 43a of the contact 43 is received in the connection recess 41a of the rotating shaft 41 and is electrically connected. In addition, the contact 43 is received in the connection recess 41a to position the rotary shaft portion 41 and prevent the rotary shaft portion 41 from rotating.

  Reference numeral 45 denotes a power supply connection unit, which is supplied with current from the apparatus main body 1. As described above, since the contact 43 is moved up and down by the air cylinder 44, when rotating the rotary shaft portion 41 and rotating the first electrode holder 42, the contact 43 is moved downward by the air cylinder 44. After the contact 43 and the connection recess 41a are disconnected and the rotary shaft 41 is rotated, the tip 43a of the contact 43 is received by the connection recess 41a by the air cylinder 44, and the contact 43 and the rotary shaft 41 are moved. Connect electrically. With such a structure, a current is supplied to the electrode 10 attached to the first electrode holder 42.

  The upper electrode unit 6 will be described below. The upper electrode unit 6 mainly includes an upper electrode unit 60, a rotating shaft portion 61, and a second electrode holder 62. The upper electrode unit 60 has a box shape, and is attached so as to be suspended from the lower end 5 a of the pressurizing mechanism 5. The rotation shaft portion 61 has a substantially cylindrical shape, and is rotatably supported by the upper electrode unit main body 61.

  The second electrode holder 62 has a flat and substantially cylindrical shape, and is attached to the front end of the rotating shaft portion 61 on the front side of the apparatus so as to be coaxial with the rotating shaft of the rotating shaft portion 61. Note that the second electrode holder 62 is electrically connected to the rotating shaft portion 61. A plurality of electrodes 10 are attached to the outer periphery of the second electrode holder 62 at a certain angle. In the present embodiment, the four electrodes 10 are attached to the second electrode holder 62 with an interval of 90 degrees. The number of electrodes attached to the electrode holder 62 is not limited to four, and may be two, three, or four or more. The cooling water is conducted through the rotating shaft 61 and the second electrode holder 62 to cool the electrode 10.

  The tip shape of the electrode 10 attached to the second electrode holder 62 is any of a flat shape, a spherical shape, a dome shape, a truncated cone shape, a truncated cone spherical shape 10b, an eccentric shape, an eccentric spherical shape, a point shape, and the like. Alternatively, different types of electrodes 10 can be attached to the second electrode holder 62.

  With such a configuration, the electrode 10 attached to the first electrode holder 42 and the electrode 10 attached to the second electrode holder 62 are detachably arranged.

  When the nut driving lower electrode 10 c is attached to the first electrode holder 42, the nut driving upper electrode 10 f is attached to the second electrode holder 62. The nut driving upper electrode 10f has a substantially cylindrical shape, and a relief hole 10g having an inner diameter larger than the outer diameter of the center pin 10e of the nut driving lower electrode 10c is formed as a recess in the center of the tip. In addition, when the size of the nut to be welded is not greatly different from the nut driving upper electrode 10f, it is possible to weld nuts having different sizes with the single nut driving upper electrode 10f. For example, when welding nuts of M5 and M6, the nut driving lower electrode 10c must be a nut driving lower electrode 10c having a size corresponding to the nuts of M5 and M6. As the upper electrode 10f, a common nut driving upper electrode 10f can be used for M5 and M6.

  On the outer peripheral surface of the rotation shaft portion 61, connection concave portions 61a that are recessed in a substantially conical shape are formed with a predetermined interval. The connection recesses 61 a are recessed in the outer peripheral surface of the rotating shaft portion 61 by the same number as the number of the electrodes 10 attached to the second electrode holder 62.

  As shown in FIG. 4, 63 is a contact, the tip 63a has a substantially conical shape, and the base 63b has a substantially cylindrical shape. The contact 63 is disposed on the lower side of the rotating shaft portion 61 and is moved left and right by the air cylinder 64 so that the tip 63a of the contact 63 can be separated from and connected to the connection recess 61a. The tip 63a of the contact 63 is received in the connection recess 61a of the rotating shaft 61 and is electrically connected. The contact 63 is received in the connection recess 61a to position the rotation shaft portion 61 and prevent the rotation shaft portion 61 from rotating.

  Reference numeral 65 denotes a power supply connection unit, which is supplied with current from the apparatus main body 1. As described above, since the contact 63 is moved left and right by the air cylinder 64, when the rotary shaft portion 61 is rotated and the second electrode holder 62 is rotated, the contact 63 is moved sideways by the air cylinder 64. After moving and disconnecting the contact 63 and the connection recess 61a and rotating the rotating shaft 61, the tip 63a of the contact 63 is received in the connection recess 61a by the air cylinder 64, and the contact 63 and the rotating shaft 61 are received. Are electrically connected. With such a structure, current is supplied to the electrode 10 attached to the second electrode holder 62.

  Next, rotating means for rotating the first electrode holder 42 will be described. As shown in FIGS. 3 and 4, substantially cylindrical drive shafts 46 and 66 are attached to the rear ends of the rotation shafts 41 and 61 so as to be coaxial with the rotation shafts 41 and 61. ing. Engagement holes 46 a are formed in the outer peripheral surface of the drive shaft portion 46 at a constant angle. The number of the engagement holes 46 a is the same as the number of the electrodes 10 attached to the first electrode holder 42.

  Reference numeral 47 denotes an air cylinder. As shown in FIG. 4, the cylinder portion 47 a of the air cylinder 47 is rotatably attached to the front-rear method of the lower electrode unit main body 40 and the end portion 40 a in the left-right direction via the bracket 55. It has been. In this embodiment, an air cylinder that operates by air pressure is used, but a hydraulic cylinder that operates by oil pressure may be used. The Y metal fitting 47 c of the air cylinder 47 is rotatably attached to the plate portion 48 a of the clutch mechanism 48.

  The clutch mechanism 48 mainly includes a plate portion 48a, a clutch pin 48b, and an air cylinder 48c. A through hole having an outer diameter slightly larger than the outer diameter of the drive shaft portion 46 is formed in the plate portion 48a, and the drive shaft portion 46 passes through the through hole so that the plate portion 48a has a drive shaft. The part 46 is rotatably attached. A mounting portion 48c is provided above the through hole of the plate portion 48a, and a Y metal fitting 47c of the air cylinder 47 is rotatably attached to the mounting portion 48c. With such a structure, the linear motion by the air cylinder 47 is transmitted as a rotational motion by the plate portion 48a. A cylindrical clutch pin 48b whose tip is narrowed is slidably housed inside the plate portion 48a so as to be swung out in the axial direction of the drive shaft portion 46. The clutch pin 48b is swung out into the engagement hole 46a of the drive shaft portion 46 by the air cylinder 48c and retracted into the plate portion 48a.

  When rotating the drive shaft portion 46 to rotate the first electrode holder 42, the air cylinder 48c is actuated to swing the clutch pin 48b into the engagement hole 46a of the drive shaft portion 46, and the clutch pin 48c. After the engagement hole 46a is engaged, the air cylinder 47 as the rotating means is operated to expand and contract the piston rod 47b of the air cylinder 47, so that the plate portion 48b rotates and the drive shaft portion 46 also rotates. . In this way, the clutch mechanism 48 transmits and blocks the rotational force of the cylinder 47 that is a rotating means to the first electrode holder 42. In this embodiment, when the piston rod 47b of the air cylinder 47 has a full stroke, the plate portion 48b rotates 90 degrees in this embodiment, and the drive shaft portion 46 also rotates 90 degrees. By repeating the above-described operation, the first electrode holder 42 can be intermittently rotated by 90 degrees, and an arbitrary electrode 10 attached to the first electrode holder 42 is selected and the second electrode holder 42 is selected. It becomes possible to arrange the electrode 10 so as to face the electrode 10 attached to the electrode holder 62.

  Hereinafter, driving means for transmitting the rotational force of the air cylinder 47 as rotating means to rotate the second electrode holder 62 will be described. The drive means mainly includes a first pinion gear 49 coaxially attached to the rear end of the drive shaft portion 46, a second pinion gear 69 coaxially attached to the rear end of the drive shaft portion 66, and these The rack gear 80 is configured to engage with the first pinion gear 49 and the second pinion gear 69 and to be detachable. The second pinion gear 69 has the same position in the front-rear direction as the first pinion gear 49, and the diameter and the number of teeth of the pitch circle of the second pinion gear 69 are the same as those of the first pinion gear 49. The same.

  The rack gear 80 is slidably accommodated in the rack holder 81. Reference numeral 82 denotes a plate, which is disposed to face the rack holder 81. The plate 82 is attached to the upper end of the lower electrode unit main body 40 by a bracket 85. Guides 83 are attached to both ends of the plate 82, and hold the rack holder 81 movably in the left-right direction of the apparatus. An air cylinder 84 is attached to the central portion of the plate 82, and the rack holder 81 is moved in the left-right direction of the apparatus so that the rack gear 80, the first pinion gear 49, and the second pinion gear are detachable. .

  Reference numeral 50 denotes a water jacket attached to the rear portion of the first pinion gear 49, for supplying cooling water to the rotary shaft portion 41, and 70 is also attached to the rear portion of the second pinion gear 69. The water jacket is for supplying cooling water to the rotating shaft portion 61. The cooling water supplied from the water jackets 50 and 70 to the rotating shaft portions 41 and 61 flows through the first and second electrode holders 42 and 62 as described above, and the respective electrode holders 42 and 62 are supplied. The electrode 10 attached to is cooled.

  As shown in FIG. 3, protrusions 86 are provided on the outer surface of the drive shaft portion 66 at a certain angle. The fixed angle is the same as the fixed angle of the electrode 10 attached to the second electrode holder 62 at a fixed angle, and is 90 degrees in this embodiment. In the state of FIG. 3, one protrusion 86 a is provided on the front side of the upper portion of the drive shaft portion 66, and two protrusions 86 b and 86 c are provided on the front side of the drive shaft portion 66. One projection 86d is provided on each. In FIG. 3, no protrusion 86 is provided on the back side of the drive shaft portion 66. In FIG. 3, two limit switches 89, 90, 91, and 92 are provided on the upper side and the near side of the drive shaft portion 66 in parallel on the front and rear sides via brackets 87 and 88, respectively. The protrusion 86 presses the limit switch at that position, and the limit switch detects the presence or absence of the protrusion 86. With this configuration, the position of the electrode 10 attached to the second electrode holder 62 is detected. For example, in FIG. 3, the protrusions 86a, 86b, and 86c press the limit switches 89, 91, and 92, respectively, and it is detected that the protrusions 86a, 86b, and 86c are present at the positions. 3 is detected. Although not shown, the lower electrode unit 2 also detects the position of the electrode 10 attached to the first electrode unit 42 by the same mechanism.

  As shown in FIG. 1, a limit switch 96 is attached to the rear end portion of the upper portion of the upper electrode unit main body 60 via a bracket 95. This limit switch 96 has a switch part 96a on the upper side, and a projection 97 for pressing the switch part 96a is attached via a bracket 98 at a position facing the limit switch 96 of the upper arm part 3. . The limit switch 96 detects that the upper electrode unit 6 that moves up and down by the pressurizing mechanism 5 is located at the uppermost part of the movable range. The limit switch 96 detects that the upper electrode unit 6 If it is not detected that it is located at the uppermost part of the movable range, the air cylinder 84 does not operate and the rack gear 80 is not engaged with the first pinion gear 49 and the second pinion gear 69. By doing so, the rack gear 80 is prevented from engaging with the second pinion gear 69 at a position where the upper electrode unit 6 is not the uppermost part of the movable range, and the second electrode holder 62 is moved to the first position. In this embodiment, the second electrode holder 62 can be reliably rotated by 90 degrees by preventing the angle of the electrode holder 42 from being shifted.

  With the structure described in detail above, when the air cylinder 47 is operated and the cylinder piston rod 47b is made a full stroke, the electrode 10 attached to the first electrode holder 42 and the second electrode holder 62 are The attached electrodes 10 are stopped at positions facing each other.

  Next, the operation of the present invention will be described. Hereinafter, a case where only the first electrode holder 42 is rotated will be described. In this case, the air cylinder 44 is operated, the contact 43 is lowered, and the connection between the contact 43 and the connection recess 41a of the rotating shaft portion 41 is released. The air cylinder 84 is actuated so that the rack gear 80 is separated from the first pinion gear 49 and the second pinion gear 69 and is disengaged. When the air cylinder 47 is operated and the piston rod 47b of the air cylinder 47 is expanded and contracted in a state where the clutch pin 48b is swung into the engagement hole 46a of the drive shaft portion 46 and engaged, the first electrode holder 42 is expanded. Only rotate 90 degrees.

  Below, the case where both the 1st electrode holder 42 and the 2nd electrode holder 62 are rotated is demonstrated. In this case, the air cylinder 84 is operated so that the rack gear 80 is engaged with the first pinion gear 49 and the second pinion gear 69. The air cylinders 44 and 64 are actuated to separate the contacts 43 and 63 from the rotating shaft portions 41 and 61, thereby releasing the connection between the contacts 43 and 63 and the connecting recesses 41 a and 61 a of the rotating shaft portions 41 and 61. After the rack gear 80 is engaged with the first pinion gear 49 and the second pinion gear 69, the connection between the contacts 43, 63 and the connection recesses 41a, 61a of the rotary shaft portions 41, 61 is released by the rack gear. This is to prevent 80 and the first pinion gear 49 and the second pinion gear 69 from engaging with each other. When the air cylinder 47 is operated and the piston rod 47b of the air cylinder 47 is expanded and contracted in this state and the clutch pin 48b is swung into the engagement hole 46a of the drive shaft portion 46 and engaged. Both the first electrode holder 42 and the second electrode holder 62 rotate 90 degrees.

  In this way, by rotating only the first electrode holder 42 by 90 degrees or by rotating both the first electrode holder 42 and the second electrode holder 62 simultaneously by 90 degrees, the first electrode holder 42 is rotated by 90 degrees. It is possible to select an arbitrary electrode 10 attached to the holder 42 and the second electrode holder 62 and to stop the electrodes 10 at the welding positions. The above control is automatically performed by the sequencer. Further, since the driving means composed of the rack gear 80, the first pinion gear 49, the second pinion gear 69 and the like transmits the rotational force of the air cylinder 47 as the rotating means, a single rotating means Thus, the first electrode holder 42 and the second electrode holder 62 can be rotated.

  The process for welding the workpieces will be described below. As described above, the air cylinder 47 as the rotating means is operated to rotate both the first electrode holder 42 and the second electrode holder 62 or only the first electrode holder 42, and the workpiece The electrodes 10 used for welding are disposed at opposing positions. The air cylinders 44 and 64 are operated so that the contacts 43 and 63 are received in the connection recesses 41a and 61a of the rotary shaft portions 41 and 61 to be electrically connected and the rotary shaft portions 41 and 61 are positioned. Thus, the rotation of the rotary shaft portions 41 and 61 is suppressed. The air cylinder 84 is operated to separate the rack gear 80 from the first pinion gear 49 and the second pinion gear 69. The air cylinder 48c of the clutch mechanism 48 is operated, and the clutch pin 48b is removed from the engagement hole 46a of the drive shaft portion 46 to be disengaged.

  Thereafter, the work piece is placed on the electrode 10 attached to the first electrode holder 42, and the pressurizing mechanism 5 is operated to bring the electrode 10 attached to the second electrode holder 62 downward. When the workpiece is lowered and energized while being pressed with the electrode 10 being pressed, the workpiece is welded by the electric resistance heat generated when the workpiece is energized.

  For example, when nuts of M5 and M6 of different sizes are sequentially welded to the workpiece, the upper electrode 10f for nut driving common to M5 and M6 can be used, and therefore the second electrode holder 62 is provided. There is no need to rotate. In this case, as described above, the rack gear 80 is separated from the first pinion gear 49 and the second pinion gear 69, and only the first electrode holder 42 is rotated by the rotating means, and the M5 and M6 are sequentially used. The nut driving bottom electrode 10c is opposed to the nut driving upper electrode 10f, and the nuts M5 and M6 are sequentially welded to the workpiece.

  In this embodiment, the rack gear 80 is configured so as to be separated from both the first pinion gear 49 and the second pinion gear 69, but the first pinion gear 49 and the second pinion gear 69 It does not matter if it is configured to be separated from either one. In the present embodiment, the first electrode holder 42 and the second electrode holder 62 are disposed so as to face each other up and down, but the first electrode holder 42 and the second electrode holder 62 face each other left and right. Needless to say, the present invention can also be applied to an electric resistance spot welding machine arranged in this manner. In the present invention, the air cylinder 47 is used as the rotating means for rotating the first electrode holder 42 and the second electrode holder 62. However, the rotating means is not limited to the air cylinder 47, and is electrically driven, for example. A stepping motor or the like can be used. Further, in the present embodiment, the embodiment in which the first electrode holder 42 and the second electrode holder 62 are rotated by a single rotating means has been described. However, each of the first electrode holder 42 and the second electrode holder 62 has been described. There is no problem even if it is a rotating means for rotating the slab independently.

  Although the present invention has been described above in connection with the most practical and preferred embodiments at the present time, the present invention is not limited to the embodiments disclosed herein. However, it can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification, and an electric resistance spot welder with such a change is also understood to be included in the technical scope. It must be.

It is a side view of the electrical resistance spot welder which shows embodiment of this invention. It is a front view of the electrical resistance spot welder which shows embodiment of this invention. It is a side view of the principal part. It is a reverse view of the principal part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Apparatus main body 2 Lower arm part 3 Upper arm part 4 Lower electrode unit 5 Pressurization mechanism 5a Lower end of pressurization mechanism 6 Upper electrode unit 10 Electrode 10b Frustum spherical electrode 10c Nut driving lower electrode 10d Base electrode 10e Center pin 10f Upper electrode for nut driving 10g Escape hole 40 Lower electrode unit main body 40a End of lower power supply unit main body 41 Rotating shaft portion 41a Connection recess 42 First electrode holder 43 Contact 43a Contact tip 43b Contact base 44 Air cylinder 45 Power connection Part 46 drive shaft part 46a engagement hole 47 air cylinder 47a cylinder part 47b piston rod 47c Y bracket 48 clutch mechanism 48a plate part 48b clutch pin 48c air cylinder 48d mounting part 49 first pinion gear 50 waterja 51 Air jacket 52 Air piping 55 Bracket 60 Upper electrode unit main body 61 Rotating shaft 61a Connection recess 62 Second electrode holder 63 Contact 63a Contact tip 63b Contact base 64 Air cylinder 65 Power supply connection 66 Drive shaft 69 First 2 pinion gear 70 water jacket 80 rack gear 81 rack holder 82 plate 83 guide 84 air cylinder 85 bracket 86 protrusion 87 bracket 88 bracket 89 limit switch 90 limit switch 91 limit switch 92 limit switch 95 bracket 96 limit switch 96a switch section 97 protrusion 98 bracket

Claims (9)

  In the electric resistance spot welder in which electrodes are respectively attached to first and second electrode holders that are detachably opposed to each other and an object to be welded is welded between the opposed electrodes, the first and second electrode holders described above In each case, a plurality of electrodes are attached to the outer periphery of the electrode holder at a certain angle, and intermittently by a predetermined angle by a rotating means so that one of the electrodes of both electrode holders is opposed and stopped at the welding position. An arbitrary one attached to the first and second electrode holders by rotating at least one of the first electrode holder and the second electrode holder by the rotating means. An electric resistance spot welder configured to weld an object to be welded by selecting and facing the electrodes and sandwiching the object to be welded between these electrodes.   2. The electric resistance spot according to claim 1, wherein the first electrode holder and the second electrode holder are rotated by a single rotating means by the driving means for transmitting the rotational force of the rotating means. Welding machine.   The rotating means rotates the first electrode holder, the driving means transmits a first pinion gear that transmits the rotational force of the first electrode holder, a second pinion gear that rotates the second electrode holder, The electrical resistance according to claim 2, comprising a rack gear that engages with the first and second pinion gears and is detachably attached to at least one of the first and second pinion gears. Spot welder.   When the rotating means rotates the first electrode holder, the rack gear is separated from at least one of the first and second pinion gears to release the engagement, so that only the first rotating holder can be rotated. The electric resistance spot welder according to claim 3.   The first pinion gear is disposed coaxially with the first electrode holder, and the second pinion gear is disposed coaxially with the second electrode holder. The electric resistance spot welding machine according to any one of the above.   The electric resistance spot welder according to any one of claims 1 to 5, wherein the rotation means is either an air cylinder or a hydraulic cylinder.   The electric resistance spot welder according to any one of claims 1 to 6, further comprising a clutch mechanism for transmitting and interrupting the rotational force of the rotating means. The clutch mechanism
A rotating shaft portion that transmits the rotational force to the first electrode holder, and a plate portion that transmits the rotational force of the rotating means;
A clutch that is housed inside the plate portion so as to be slidable in the axial direction of the rotation shaft portion, and is engaged by being swung out into an engagement hole formed in a recess at a certain angle on the outer peripheral surface of the rotation shaft portion. The electric resistance spot welder according to claim 7, further comprising a pin.   On the outer peripheral surface of the rotating shaft that transmits the rotational force of the rotating means to the electrode holder, a connection recess is formed at a certain angle to receive the tip of the contact through which the welding current flows, and the tip of the contact is connected to the electrode holder. The electrical resistance spot welder according to any one of claims 1 to 8, wherein the contact is configured to be detachable from the recess.

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