JP3143309U - Lower electrode unit with set defect detection function - Google Patents

Abstract

There is provided a lower electrode unit with a set defect detection function capable of sufficiently cooling a lower electrode without an upper portion of a lower electrode holder being enlarged.
A lower electrode unit with a set defect detection function mainly includes a lower electrode, a lower electrode holder, a guide pin, a shaft, a housing, a cylinder, and a length measuring unit. . The lower electrode holder 2 is divided into upper and lower parts, the upper side is the water cooling unit 10, the lower side is the power feeding unit 20, and a cooling water channel through which the cooling water flows is formed in the water cooling unit 10.
[Selection] Figure 1

Description

  The present invention can easily and reliably detect whether or not the supply of the weld nut or the workpiece is normally performed when the weld nut is welded to a flat plate or the like which is a workpiece with a stationary spot welder. It relates to the lower electrode unit with the function of detecting a set failure

  Conventionally, a lower electrode as shown in Patent Document 1 (particularly, FIGS. 5 and 6) has been used to manufacture an automotive panel or the like in which a nut is welded to a flat plate. The weld nut has a plurality of projections on its seating surface. During welding, a flat plate and a weld nut nut are set between the upper and lower electrodes, and pressurization / energization is performed. The electric current is concentrated at the time of melting, melted during welding, and welded to a flat plate. In this case, the flat plate and the nut are usually automatically supplied by a robot or the like, and the welding process is automatically and continuously performed.

  However, there is no problem if the workpiece and nut are always of the specified size and are supplied to a fixed position, but in reality the shape of the nut etc. may be different or the supply position may be misaligned. In robot welding, there is a problem that the welding process is unconditionally executed even in such a case. As a result, there is a problem in that defective products such as double workpieces, different nut sizes, reverse nuts, no nuts, workpiece misalignment, nut misalignment, nut protrusion collapse, nut lateral orientation, and lateral misalignment are generated.

  In view of this, a lower electrode unit with a nut setting failure detection function as shown in Patent Document 2 has been proposed. As shown in FIG. 8, this lower electrode unit with a set failure detection function is provided with a lower electrode holder 121 having a lower electrode 122 attached to the upper end thereof, and a guide pin 123 having an upper end protruding slidably disposed. A cylinder 124 is provided at the lower end of the holder 121, a guide pin 123 and a cylinder rod 124 a of the cylinder 124 are connected by a shaft 125, and a digital length measuring unit 126 for measuring the descending amount of the cylinder rod 124 a during welding is provided. It is configured to detect whether or not the weld nut is normally set.

At the time of welding, the lower electrode 122 is exposed to a high temperature, so that it is softened and easily deformed. Therefore, conventionally, the lower electrode 122 is cooled by attaching a water cooling jacket 127 as shown in FIG. 8 to the outer periphery of the upper part of the lower electrode holder 121 and cooling the lower electrode holder 121. Since this water cooling jacket 127 is attached to the outer periphery of the upper part of the lower electrode holder 121, the upper part of the lower electrode holder 121 becomes large, and there is a case where the workpiece interferes with welding.
Actual climbing 3130582 JP 2006-21226 A

  An object of the present invention is to solve the above problems and to provide a lower electrode unit with a defective set detection function capable of sufficiently cooling the lower electrode without increasing the upper portion of the lower electrode holder.

In order to solve the above-mentioned problem, the present invention according to claim 1 includes a cylindrical lower electrode disposed oppositely below the upper electrode, and a spot welder holding the lower electrode below the lower electrode. A cylindrical lower electrode holder that is gripped by the main body and fed from the spot welder, and a guide that protrudes upward from the lower electrode through the lower electrode and is slidably disposed in the lower electrode holder It is equipped with a pin and a length measuring mechanism that measures the descending distance of the guide pin, a member to be welded is placed on the lower electrode, a screw hole of a weld nut is held by the guide pin, and the upper electrode is lowered, The length measuring mechanism memorizes the amount of lowering of the guide pin when the member to be welded and the weld nut are sandwiched between the upper electrode and the lower electrode as a reference distance, and the guide measured by the length measuring mechanism at the time of welding. A lower part with a set failure detection function configured to detect a set failure of the welded member or the weld nut by determining whether or not the descent distance of the pin is within a preset range from the reference distance In the electrode unit,
The lower electrode holder is divided into upper and lower parts, the upper part is a water cooling part, the lower part is a power feeding part that is gripped by the spot welder body and fed with power from the spot welder, and the cooling water circulates in the water cooling part. A cooling water channel is formed.

The device according to claim 2 comprises the water cooling unit according to claim 1.
A cylindrical electrode mounting member for attaching a lower electrode to the upper end thereof;
A cylindrical inner member attached to the upper end of the electrode attachment member, the lower end of which is attached to the upper end of the power feeding unit,
A mounting hole having an inner diameter slightly larger than the outer diameter of the inner member is formed to communicate with the upper and lower sides, and a cooling water circulation recess is formed in the inner peripheral surface of the mounting hole over the entire circumference. The inner member is inserted and configured with an outer member attached so as to cover the outer peripheral surface of the inner member,
A space constituted by the outer peripheral surface of the inner member and the cooling water circulation recess of the outer member is a cooling water channel.

  According to a third aspect of the present invention, in the device according to the second aspect, a support portion having an outer diameter larger than the outer diameter of the intermediate portion is formed below the intermediate portion of the inner member. The lower end of the outer member is supported, and the upper end of the outer member is in contact with the electrode mounting member.

  The device according to claim 4 is the device according to claim 2 or 3, wherein an O-ring for sealing the outer member and the inner member is attached to the position adjacent to the upper and lower portions of the cooling water flow path. Features.

The present invention as set forth in claim 1 includes a cylindrical lower electrode disposed oppositely below the upper electrode, and the lower electrode held below the lower electrode and held by the spot welder main body. A cylindrical lower electrode holder that is fed from, a guide pin that penetrates the lower electrode and protrudes upward from the lower electrode, and is slidably disposed in the lower electrode holder, and a lowering distance of the guide pin A measuring mechanism for measuring is provided, a member to be welded is placed on the lower electrode, a screw hole of a weld nut is held by the guide pin, the upper electrode is lowered, and the welded member is welded by the upper electrode and the lower electrode The length measurement mechanism memorizes the amount of lowering of the guide pin when the member and the weld nut are sandwiched as a reference distance, and whether the distance of lowering of the guide pin measured by the length measurement mechanism during welding is the reference distance. By determining whether or not within a preset range, in the fabricated set failure detection function lower electrode unit so as to detect a set failure of the member to be welded and the weld nut,
The lower electrode holder is divided into upper and lower parts, the upper part is a water cooling part, the lower part is a power feeding part that is gripped by the spot welder body and fed with power from the spot welder, and the cooling water circulates in the water cooling part. A cooling water channel is formed.
Therefore, it is possible to provide a lower electrode unit with a defective set detection function that can sufficiently cool the lower electrode without increasing the upper portion of the lower electrode holder.

The device according to claim 2 comprises the water cooling unit according to claim 1.
A cylindrical electrode mounting member for attaching a lower electrode to the upper end thereof;
A cylindrical inner member attached to the upper end of the electrode attachment member, the lower end of which is attached to the upper end of the power feeding unit,
A mounting hole having an inner diameter slightly larger than the outer diameter of the inner member is formed to communicate with the upper and lower sides, and a cooling water circulation recess is formed in the inner peripheral surface of the mounting hole over the entire circumference. The inner member is inserted and configured with an outer member attached so as to cover the outer peripheral surface of the inner member,
A space constituted by the outer peripheral surface of the inner member and the cooling water circulation recess of the outer member is a cooling water channel.
For this reason, it is possible to realize a structure of a lower electrode unit with a set defect detection function that can sufficiently cool the lower electrode without increasing the upper portion of the lower electrode holder.

According to a third aspect of the present invention, in the device according to the second aspect, a support portion having an outer diameter larger than the outer diameter of the intermediate portion is formed below the intermediate portion of the inner member. The lower end of the outer member is supported, and the upper end of the outer member is in contact with the electrode mounting member.
Therefore, even when a force is applied to the lower electrode and a force is applied to the electrode mounting member during welding, the electrode mounting member is supported by the outer member, and further, the outer member is supported by the support portion of the inner member. Therefore, a large force does not act on the middle part of the inner member, and the cooling part can be prevented from being damaged.

The device according to claim 4 is the device according to claim 2 or 3, wherein an O-ring for sealing the outer member and the inner member is attached to the position adjacent to the upper and lower portions of the cooling water flow path. Features.
For this reason, it becomes possible to prevent the leakage of cooling water.

(Structure of spot welding electrode for weld bolt welding)
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a front view of a lower electrode unit 50 with a set defect detection function. The lower electrode unit 50 with a defective set detection function mainly includes a lower electrode 1, a lower electrode holder 2, a guide pin 3, a shaft 4, a housing 5, a cylinder 6, and a length measuring unit 7. In the present invention, the lower electrode holder 2 is divided into two in the vertical direction to form a two-body structure, with the water cooling unit 10 on the upper side and the power feeding unit 20 on the lower side.

  The lower electrode 1 has a cylindrical shape, and has a communication hole 1a that communicates vertically with the center. The lower electrode 1 is made of a copper alloy such as beryllium copper, zirconium copper, or chromium copper. The lower electrode 1 is attached to the upper end of the electrode attachment member 11 of the water cooling part 10 mentioned later.

  In the communication hole 1a of the lower electrode 1, a substantially bullet-shaped guide pin 3 is slidably disposed. The tip of the guide pin 3 protrudes upward from the communication hole 1a. The guide pin 3 is made of KCF (stainless steel, whose surface is treated with an insulating coating).

  The water cooling unit 10 is attached to the upper end of the cylindrical power supply unit 20. The power feeding unit 20 is made of a copper alloy such as chromium copper, pure copper, or the like. The power feeding unit 20 is held by a spot welder main body (not shown), and current is supplied from the spot welder main body.

  A box-shaped housing 5 is attached to the lower end of the power feeding unit 20. FIG. 1 shows a state in which the lid of the housing 5 is detached from the housing 5 so that the internal structure inside the housing 5 can be seen.

  A shaft 4 connected to the guide pin 3 is slidably disposed in the water cooling unit 10 and the power feeding unit 20. The lower part of the shaft 4 is located in the housing 5.

  A cylinder 6 is attached in the housing 5. In this embodiment, the cylinder 6 is an air cylinder, and the cylinder shaft 6a moves in the vertical direction.

  The lower part of the shaft 4 is connected to the cylinder shaft 6 a via the bracket 8. With this configuration, the guide pin 3 is moved up and down by the cylinder 6. When the guide pin 3 is moved downward, the tip of the guide pin 3 is completely housed in the communication hole 1a of the lower electrode 1 and does not protrude from the upper surface of the lower electrode 1.

  A length measuring unit 7 is disposed in the housing 5. In the present embodiment, the length measuring unit 7 is attached to the cylinder 6. The length measuring unit 7 is a device that has a measuring portion 7a and a length measuring rod 7a that moves in the vertical direction with respect to the measuring portion 7a, and detects the position of the length measuring rod 7a with respect to the measuring portion 7a. In the present embodiment, the length measuring unit 7 is configured by a so-called potentiometer that converts the position of the length measuring rod 7a into a voltage. The measuring rod 7 a is connected to the bracket 8. With this configuration, the position of the guide pin 3 with respect to the lower electrode 1 can be measured in the vertical direction. The length measuring unit 7 is connected to a controller (not shown).

  2 shows a front view of the water cooling unit 10, FIG. 3 shows a side view of the water cooling unit 10, FIG. 4 shows a top view of the water cooling unit 10, FIG. 5 shows a cross-sectional view of the water cooling unit 10, The water cooling unit 10 will be described in detail. As shown in FIGS. 2 to 5, the water cooling unit 10 includes an electrode mounting part 11, an outer member 12, an inner member 13, an O ring 14, an O ring 15, an inflow jack 16, and an outflow jack 17. .

  The electrode mounting member 11 has a cylindrical shape. The electrode mounting member 11 is made of a copper alloy such as chromium copper. The entire inner peripheral surface of the electrode mounting member 11 is threaded with a thread groove to form a screw portion 11a. The lower electrode 1 is attached with the screw portion 11a.

  The inner member 13 has a substantially cylindrical shape. The inner member 13 is made of a copper alloy such as chromium copper. The inner member 13 includes, in order from the top to the bottom, a screw portion 13a, a middle portion 13b, a support portion 13c, and a screw portion 13d. The outer diameter of the support portion 13c is larger than the outer diameter of the intermediate portion 13b, and is almost the same as the outer diameter of the electrode mounting member 11 and the power feeding portion 20. The screw part 13 d of the inner member 13 is screwed into the upper end of the power feeding part 20, and the cooling part 10 is attached to the power feeding part 20.

  The external material 12 has a block shape and is made of a copper alloy such as chromium copper. A mounting portion 12a that communicates vertically is formed on the external material. The cross-sectional shape of the attachment portion 12a is circular. The inner diameter of the mounting portion 12 a is slightly larger than the outer diameter of the inner member 13. The middle part 13 b of the inner member 13 is inserted into the mounting part 12 a of the outer member 12 to attach the outer member 12 to the inner member 13. In a state where the external member 12 is attached to the inner member 13, the screw portion 13 a of the inner member 13 protrudes upward from the attachment portion 12 a of the outer member 12. The electrode attachment member 11 is attached to the inner member 13 by screwing the screw portion 11 a of the electrode attachment member 11 into the attachment portion 13 a of the inner member 13. The lower end of the electrode attachment member 11 is in contact with the upper end of the outer member 12. The lower end of the outer member 12 is in contact with the support portion 13 c of the inner member 13. For this reason, even when a downward force is applied to the electrode mounting member 11 during welding, the electrode mounting member 11 presses the outer member 12 downward, and the outer member 12 supports the support portion 13c of the inner member 13. Since a large force does not act on the screw part 11a of the electrode mounting member 11 and the screw part 13a of the inner member 13, the screw parts 11a and 13a are not damaged. Yes. In addition, since a large force does not act on the middle part 13b of the inner member 13, the middle part 13b is not damaged.

A cooling water circulation recess 12b is formed in the middle of the attachment portion 12a so as to extend over the entire circumference.
An inflow port 12c and an outflow port 12d that open to the outer surface of the external member 12 communicate with the cooling water circulation recess 12b. A space constituted by the cooling water circulation recess 12b and the outer peripheral surface of the middle part of the inner member 13 serves as a cooling water channel 19 through which the cooling water flows. As shown in FIG. 2, the inflow jack 16 is attached to the inflow port 12c, and the outflow jack 17 is attached to the outflow port 12d. As shown in FIGS. 2 and 5, the inlet 12 c and the outlet 12 d are formed on the same side of the outer member 12. For this reason, the inflow jack 16 and the outflow jack 17 are attached to the same side of the outer member 12, and do not get in the way.

  O-ring housing recesses 12e and 12f are respectively formed in recesses over the entire circumference at positions adjacent to the upper and lower sides of the coolant circulation recess 12b on the inner surface of 12a. O-rings 14 and 15 are housed and attached to the O-ring housing recesses 12e and 12f, respectively. These O-rings 14 and 15 seal the space between the outer peripheral surface of the intermediate portion 13 b of the inner member 13 and the outer member 12, and prevent the cooling water from leaking from the cooling water flow path 19.

(Operation of the present invention)
FIG. 6 shows a state of use during welding, and the operation of the present invention will be described below. Reference numeral 71 denotes a member to be welded, in which a mounting hole is formed. Reference numeral 72 denotes a weld nut, and a plurality of projections 72a project from the seat surface. The projection 72a is attached so that the current is concentrated at the time of electric resistance spot welding, melted at the time of welding, and melted with the molten metal of the member to be welded 71 and integrated with the member to be welded 71. An upper electrode 60 is disposed on the lower electrode 1 so as to face the lower electrode 1.

  By gripping and moving the welded member 71 by the robot arm, the tip of the guide pin 3 is inserted into the mounting hole of the welded member 71 and the welded member 71 is placed on the lower electrode 1. Next, the weld nut 72 is supplied to the guide pin 3 by the nut feeder, and the screw hole of the weld nut 72 is inserted into the guide pin 3 and held. In this state, the cylinder 6 is in a state where the guide pin 3 is lifted up, the weld nut 72 is lifted up, and the projection 72 a of the weld nut 72 is separated from the welded member 71. Yes.

  Next, when the weld nut 72 is pressed by the upper electrode 60 and pressed downward (when the welded member 71 and the weld nut 72 are sandwiched between the upper electrode 60 and the lower electrode 1), the projection 72 a is connected to the welded member 71. In contact with each other, the weld nut 72 and the welded member 71 are energized, the projection 72 a is melted, and the weld nut 72 is welded to the welded member 71. At this time, the guide pin 3 is lowered, and the length measuring unit 7 measures the lowered distance of the guide pin 3. (State of FIG. 7)

  The control box connected to the length measuring unit 7 is normally operated from the state where the welded member 71 and the weld nut 72 are set (the state shown in FIG. 6) to the center pin during welding (the state shown in FIG. 7). The descent distance of 3 is stored as a reference distance. If at least one of the welded member 71 and the weld nut 72 is not set in the lower electrode unit 50 with the setting failure detection function, the lowering distance of the center pin 3 becomes shorter than the reference distance, so that the control The box detects a set failure of the welded member 71 or the weld nut 72. Further, when a welded member 71 having a thin plate thickness or a weld nut smaller than the regular weld nut 72 is set in the lower electrode unit 50 with a setting failure detection function, the descending distance of the center pin 3 is determined as the reference distance. Since the distance is shorter than the distance, the control box detects a set failure of the welded member 71 or the weld nut 72. Further, when two or more weld nuts 72 are set on the center pin 3, or when a weld nut larger than the regular weld nut 72 is set on the lower electrode unit 50 with a setting failure detection function, When the nut 72 is set on the center pin in a tilted state, the lowering distance of the center pin 3 becomes longer than the reference distance, so the control box detects a setting failure of the weld nut 72. In the present invention, the set distance of the welded member 71 or the weld nut 72 is detected by determining whether or not the descending distance of the guide pin during welding is within a preset range from the reference distance. Yes.

  When the welding of the welded member 71 and the weld nut 72 is completed, the cylinder 6 is operated to lower the shaft 4 to lower the guide pin 3 so that the tip of the guide pin 3 does not protrude from the lower electrode 1. Then, the welded member 71 to which the weld nut 72 is welded is grasped by the robot arm and taken out from the lower electrode 1.

  The lower electrode 1 is heated by the heat generated when the weld nut 72 is welded to the welded member 71, but the cooling water supplied from the inflow jack 16 flows through the cooling water flow passage 19, Since the electrode attachment member 11 is cooled, the lower electrode 1 attached to the electrode attachment member 11 is not overheated and the life of the lower electrode 11 is extended. The cooling water that has cooled the electrode mounting member 11 is discharged from the outflow jack 17 to the outside.

  Although the present invention has been described above in relation to the most practical and preferred embodiments at the present time, the present invention is not limited to the embodiments disclosed herein. The lower electrode unit with a set failure detection function accompanying such a change is also included in the technical scope without departing from the spirit or idea of the invention that can be read from the claims and the entire specification. It must be understood as a thing.

It is a front view of the lower electrode unit with a set defect detection function of the present invention. It is a front view of a water cooling part. It is a side view of a water cooling part. It is a top view of a water cooling part. It is sectional drawing of a water cooling part. It is explanatory drawing at the time of welding. It is explanatory drawing at the time of welding. It is explanatory drawing of the conventional lower electrode unit with a set defect detection function.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lower electrode 1a Communication hole 2 Lower electrode holder 3 Guide pin 4 Shaft 5 Case 6 Cylinder 6a Cylinder shaft 7 Measuring unit 7a Measuring part 7b Measuring rod 8 Bracket 10 Water cooling part 11 Electrode attachment member 11a Screw part 12 External material 12a Mounting portion 12b Cooling water flow recess 12c Inlet 12d Outlet 12e O-ring storage recess 12f O-ring storage recess 13 Inner member 13a Screw portion 13b Intermediate portion 13c Support portion 13d Screw portion 14 O-ring 15 O-ring 16 Inflow jack 17 Outflow jack DESCRIPTION OF SYMBOLS 19 Cooling water flow path 20 Power supply part 50 Lower electrode unit with set defect detection function 60 Upper electrode 71 Welded member 72 Weld nut 72a Projection 72b Screw hole 72c Tapered surface 80 Weld bolt welding electrode 121 Lower part Electrode holder 122 lower electrode 123 guide pin 124 cylinder 124a cylinder rod 125 shaft 126 Measuring unit 127 cooling jacket

Claims (4)

A cylindrical lower electrode disposed oppositely below the upper electrode, and a cylindrical lower electrode holder that holds the lower electrode below the lower electrode, is held by the spot welder body, and is fed from the spot welder And a guide pin that protrudes upward from the lower electrode through the lower electrode and is slidably disposed in the lower electrode holder, and a length measuring mechanism that measures a descending distance of the guide pin, Place the welded member on the electrode, hold the screw hole of the weld nut with the guide pin, lower the upper electrode, and sandwich the welded member and the weld nut with the upper electrode and the lower electrode The measuring mechanism memorizes the descending amount of the guide pin as a reference distance, and the descending distance of the guide pin measured by the measuring mechanism at the time of welding is within a preset range from the reference distance. By determining whether, in the fabricated set failure detection function lower electrode unit so as to detect a set failure of the member to be welded and the weld nut,
The lower electrode holder is divided into upper and lower parts, the upper part is a water cooling part, the lower part is a power feeding part that is gripped by the spot welder body and fed with power from the spot welder, and the cooling water circulates in the water cooling part. A lower electrode unit with a defective set detection function, wherein a cooling water channel is formed. Water cooling section,
A cylindrical electrode mounting member for attaching a lower electrode to the upper end thereof;
A cylindrical inner member attached to the upper end of the electrode attachment member, the lower end of which is attached to the upper end of the power feeding unit,
A mounting hole having an inner diameter slightly larger than the outer diameter of the inner member is formed to communicate with the upper and lower sides, and a cooling water circulation recess is formed in the inner peripheral surface of the mounting hole over the entire circumference. The inner member is inserted and configured with an outer member attached so as to cover the outer peripheral surface of the inner member,
2. The lower electrode unit with a set defect detection function according to claim 1, wherein a space constituted by an outer peripheral surface of the inner member and a cooling water circulation recess of the outer member is a cooling water channel.   A support portion having an outer diameter larger than the outer diameter of the intermediate portion is formed below the intermediate portion of the inner member, and the lower end of the outer member is supported by the support portion, and the upper end of the outer member is connected to the electrode mounting member. The lower electrode unit with a set defect detection function according to claim 2, wherein the lower electrode unit is configured to abut.   The lower electrode unit with a set defect detection function according to claim 3 or 4, wherein an O-ring for sealing the outer member and the inner member is attached to positions adjacent to the upper and lower sides of the cooling water flow path.

Images