JP2837817B2 - Upper electrode cover for nut welding and nut anomaly detector for nut welding welder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nut welding upper electrode cover capable of detecting whether or not the position and orientation of a nut is normal when welding a nut automatically supplied by a nut feeder to a workpiece. The present invention relates to a nut abnormality detection device and a nut abnormality detection method for a nut welding welding machine.

[0002]

2. Description of the Related Art Generally, when a nut automatically supplied by a nut feeder is welded to a workpiece by a nut welding machine having an upper electrode and a lower electrode, it is determined whether or not the nut is in a normal posture. After detecting, the nut is welded to the work. Therefore, when welding a nut to a workpiece, a nut welding welder described below is conventionally known as a nut welding welder that detects whether the posture of the nut is normal or not and performs welding.

[0003] For example, a conventional welding machine for nut welding has an upper electrode and a lower electrode, an interlocking rod is connected to the upper electrode, and a height adjusting bolt is provided on the interlocking rod. A limit switch is provided below the adjustment bolt, and the lower end of the height adjustment bolt abuts against the limit switch to turn on the limit switch. The height of the interlock rod is lowered by lowering the upper electrode, and the height adjustment bolt is lowered integrally with the interlock rod, and the lower end of the height adjustment bolt contacts the limit switch. Whether or not the position of the nut when welding is normal is detected based on whether or not this limit switch is turned on. When it is detected that the nut is normal, the upper electrode and the lower electrode are energized to warm the nut. There are things to be welded to.

In Japanese Utility Model Publication No. 60-39172,
A welding device including a detection collar provided on an upper electrode and a detection switch is described. In this welding device, the sleeve-shaped detection collar projects downward from the lower end surface of the upper electrode by a dimension slightly smaller than the height of the nut, and is supported on the upper electrode so as to be slidable in the vertical direction. Have been. In the case of a nut supplied in a normal position, the detection collar does not contact the nut, the upper electrode contacts the nut, and welding current is applied, but the nut has shifted from the normal position. When supplied to the position, the collar abuts the nut, the tip of the collar is relatively lifted up to near the tip of the upper electrode, the detection switch is activated, and the welding current is not supplied. .

Further, the components of the detection device of Japanese Utility Model 59-175490 publication, a ring-shaped member similar to insulation cover is described. This ring-shaped detection member has an insulating property, and is detachably attached to an outer peripheral portion of the upper electrode, and a lower end portion of the ring-shaped detection member protrudes below the tip surface of the upper electrode so as to be shorter than the height of the nut, and is supported. ing. When the nut is supplied in a normal posture, when the upper electrode is driven downward, the upper electrode comes into contact with the nut and the welding current is conducted, but when the nut is supplied in an abnormal posture, The detection member is configured to be in contact with the nut so that the welding current is not supplied.

Further, Japanese Utility Model Publication No. 3-24299 discloses an electrode for welding a pilot hole nut. On the outer peripheral portion of the upper electrode body of this prepared hole nut welding electrode, a mis-weld prevention ring is fixed via an electrical insulating ring, with its distal end slightly facing the distal end of the upper electrode main body. When the nut is in the normal position, the nut abuts on the upper electrode and the welding current flows, but when the nut is supplied in the opposite direction to the normal position, the wrong welding prevention ring is used. Is configured such that the lower end of the abutment comes into contact with the nut so that no welding current flows.

[0007]

However, the conventional welding machine for nut welding has the following problems. In the welding machine for nut welding provided with the limit switch, by detecting the height of the nut,
In order to detect whether or not it is in a normal posture,
Even when the nut is out of the normal position or when the nut is in the upside down position, the nut is in the normal position because the height of the nut is the same as that in the normal position. The lower end of the height adjustment bolt contacts the limit switch, and this limit switch is
N, the welding of the nut is performed even in this state, so that there is a problem that defective welding products are produced. As described above, when the nut is at a position deviated from the normal position or when the nut is upside down, there is a problem that detection is impossible.

Further, when the nut is not supplied, the lower end of the height adjusting bolt is further lowered even after the limit switch comes into contact with the limit switch and the limit switch is turned on. As a result, the limit switch is damaged. There is a problem. In the case of a lever type limit switch, there is a problem that the lever is pushed extremely and the lever is deformed. Further, each time the electrode is polished, the position of the lower end of the height adjusting bolt must be adjusted, so that there is a problem that this adjusting operation is difficult and requires a long time for this operation.

[0009] In the actual public Akira 60-39172 publication, since the inner diameter of the sleeve-like sensing color is formed to have a larger diameter than the outer diameter of the nut, even when the nut is being supplied to come GyakuMuko, nut Penetrates into the collar, and the tip of the collar cannot be lifted by the tip of the upper electrode. Therefore, despite the nuts being supplied in the opposite direction,
Since the detection switch does not operate, the welding current is supplied,
There is a problem that defective welding products appear.

Further, in the nut welding machine disclosed in Japanese Utility Model Laid-Open Publication No. 59-175490, when the nut is supplied in an oblique state, both ends of the nut contact the upper electrode and the lower electrode. As a result, the welding current is conducted, so that welding is performed, and there is a problem that defective welding products are produced. Also, after polishing the upper electrode, the upper and lower dimensions of the upper electrode are shortened, and the ring-shaped detection member protrudes longer than the initial set length. Comes in contact with the nut,
Since the upper electrode does not contact the nut, there is a problem that welding current is not supplied.

According to Japanese Utility Model Publication No. 3-24299, when the nut is inclined, both ends of the nut come into contact with the upper electrode body and the lower electrode body. In addition, since the welding current is supplied, there is a problem that welding is performed and defective welding products are produced. Furthermore, the ring for preventing mis-welding has an integral structure fixed to the upper electrode main body via the electric insulating ring, and the lower end surface of the upper electrode main body cannot be polished,
In addition, when the upper electrode is removed and disposed, the insulated electrode cover must be removed and disposed at the same time, resulting in a problem that the cost is increased.

[0012]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a nut welding upper electrode capable of accurately detecting whether or not a nut is in a normal position and posture immediately before a nut is welded, and preventing defective welding of the nut. to provide a nut abnormality detection equipment cover and the nut welding welder.

[0014]

According to a first aspect of the present invention, there is provided an upper electrode cover for nut welding, wherein the upper electrode cover is externally fitted to an upper electrode of the welding machine for nut welding. An electrode cover which is detachably mounted on the upper electrode, and a flange portion which is fixed to an outer peripheral portion of a lower end surface of the upper electrode at a lower end portion of the electrode cover. When provided an opening that can accommodate only a nut body of the nut loosely fitted, this
Guide taper surface with larger diameter at the inner circumference of the opening at the bottom
Forming an annular groove in the inner peripheral surface of the electrode cover body.
Attach a heat-resistant O-ring to this annular groove,
The electrode cover is held on the upper electrode via
It has been achieved .

According to a second aspect of the present invention, there is provided an upper electrode cover which is externally fitted to an upper electrode of a nut welding welder provided with a height position detecting means for detecting a height position of the upper electrode. An electrode cover detachably attached to the upper electrode is provided, and only a flange fixed to an outer peripheral portion of a lower end surface of the upper electrode and a nut main body of the nut are loosely fitted at a lower end of the electrode cover. and an opening which can be accommodated in provided, Te for guidance diameter increases as downward in the inner peripheral portion of the opening
Forming an annular groove in the inner peripheral surface of the electrode cover, attaching a heat-resistant O-ring to the annular groove, and holding the electrode cover on the upper electrode via the O-ring. It is composed .

According to a third aspect of the present invention, there is provided a nut abnormality detecting device for a nut welding welder, comprising: an upper electrode; a lower electrode opposed to the upper electrode; On the upper electrode
An electrode cover that is freely fitted to the outside, and at the lower end thereof,
A flange fixed to an outer peripheral portion of a lower end surface of the upper electrode;
Opening that can accommodate only the nut body of the
A guide formed on the inner periphery of this opening and having a larger diameter as it goes downward.
An electrode cover having a tapered surface for use, a detected member connected to the upper electrode, and immediately before welding in which the upper electrode is lowered to a welding position, via the detected member,
A height position detection determining means for detecting whether or not the height position of the upper electrode is within a predetermined height range.

According to a fourth aspect of the present invention, there is provided a nut abnormality detecting device for a nut welding welder according to the third aspect of the present invention, which receives an output of the height position detecting and judging means, and when the output is within the predetermined height range, the nut abnormality is detected. Control means for instructing execution of welding and for activating alarm means when the height is not within the predetermined height range is provided. According to a fifth aspect of the present invention, there is provided a nut abnormality detecting device for a nut welding welder according to the third or fourth aspect , further comprising a fine adjustment mechanism for finely adjusting the height position of the detected member with respect to the upper electrode.

According to a sixth aspect of the present invention, there is provided a nut abnormality detecting device for a nut welding welder, comprising: an upper electrode; a lower electrode opposed to the upper electrode; and an elevating drive means for driving the upper electrode up and down. In the machine, an electrode cover detachably fitted to the upper electrode, the lower end thereof,
An opening capable of accommodating only the flange portion and the nut body portion of the nut which are locked to the outer peripheral portion of the lower end surface of the upper electrode, and a guide formed on the inner peripheral portion of the opening and having a larger diameter toward the lower side. An electrode cover having a tapered surface for use, a detected member connected to the upper electrode, a height position detecting means including encoder means for detecting a height position of the upper electrode via the detected member, First determining means for receiving an output of the height position detecting means and determining whether or not the height position of the upper electrode in a state immediately before welding in which the upper electrode is lowered to the welding position is within a predetermined height range; It is a thing.

According to a seventh aspect of the present invention, in the nut abnormality detecting device for a nut welding welder according to the sixth aspect of the present invention, when the output of the first determining means is received and the position is within the predetermined height range,
Control means for instructing the welding machine to execute welding and for activating alarm means when the height is not within the predetermined height range is provided. The nut abnormality detecting device for a welding machine for nut welding according to claim 8 is the invention according to claim 6 or 7 ,
A fine adjustment mechanism for finely adjusting the height position of the detected member with respect to the upper electrode is provided.

A ninth aspect of the present invention provides the nut abnormality detecting device for a nut welding machine according to the seventh aspect of the present invention, wherein the output of the height position detecting means receives the output of the height position detecting means, and the upper electrode in the state immediately after welding when the nut is welded. A second determining means for determining whether or not the height position is within a set height range; receiving an output of the second determining means; when the height position is within the set height range, outputting a welding completion command; And control means for activating the alarm means when the height is not within the set height range.

According to a tenth aspect of the present invention, in the nut abnormality detecting device for a nut welding welder according to the seventh aspect of the present invention, the height position detecting means detects the upper electrode from the height position of the upper electrode lowered to the lower limit position. It has an origin position setting means for setting the origin height position of the electrode .

[0022]

According to the first aspect of the present invention, a nut welding upper electrode cover includes an electrode cover main body, an insulating member for insulating the electrode cover main body from the upper electrode, and is detachably attached to the upper electrode. The lower end of the electrode cover is provided with a flange portion which is locked to the outer peripheral portion of the lower end surface of the upper electrode, and an opening which can accommodate the nut main body portion of the nut in a loosely fitting manner, A guide taper surface with a larger diameter is formed on the inner periphery of the opening downward, so that when the nut is supplied in a normal posture, the nut body is inserted into the opening of the upper electrode cover for nut welding. part is narrowing enters,
Since the upper surface of the nut to the lower end of the upper electrode contact and welding current is supplied, the nut is welded in a normal posture.

On the other hand, when the nut is being supplied in a state not a normal posture, as described below, the electrodes cover, the nut is not welded. First, in the state in which the nut is not supplied, the flange portion of the electrodes cover abuts against the upper surface of the lower electrode, since the welding current is not energized, the nut is not welded. Further, when the nut is supplied at a position shifted from the normal position, the flange portion of the electrodes cover abuts against the upper surface of the nut, since the welding current is not energized, the nut is not welded.

[0024] When the nut is being supplied in a posture of upside down, the flange portion of the pole cover electrodeposition onto welds formed to protrude outwardly from the bottom of the nut abuts the welding current is not energized Therefore, the nut is not welded. In other words, according to this nut welding upper electrode cover, when the nut is supplied in a normal posture, the nut body of the nut
Department enters the opening of the electrodes covers only this case, since the welding current to the upper and lower electrodes is energized, it is possible to weld nuts in a normal posture.

Further, the electrode cover is provided with a flange portion, and the electrode cover is held on the upper electrode via a heat-resistant O-ring. Therefore, when polishing the lower end surface of the upper electrode, the electrode cover is not polished. After removing the upper electrode from the upper electrode and polishing it, the same electrode cover can be easily attached to the upper electrode by locking its flange to the outer periphery of the lower end surface of the upper electrode, and even when replacing the upper electrode. Then, the electrode cover is removed from the upper electrode, and the same electrode cover can be easily mounted on the newly set upper electrode by locking the flange portion to the outer periphery of the lower end surface of the upper electrode. This allows the electrode cover to be used repeatedly when polishing and replacing the upper electrode, so that the cost can be reduced. in this way,
The attachment and detachment of the electrode cover and the holding on the upper electrode can be easily performed via the O-ring .

In the nut electrode upper cover according to the second aspect, the nut electrode is mounted on the upper electrode of the nut welding machine provided with a height position detecting means for detecting the height position of the upper electrode. An electrode cover which is detachably mounted is provided. A lower end portion of the electrode cover has a flange portion which is engaged with an outer peripheral portion of a lower end surface of the upper electrode, and an opening which can accommodate a nut main body portion of the nut in a loose fit. And a guide taper surface having a larger diameter toward the lower side is formed in the inner peripheral portion of the opening, an annular groove is formed in the inner peripheral surface of the electrode cover, and a heat-resistant O-ring is formed in the annular groove. And the electrode cover is held on the upper electrode via the O-ring. When the nut is supplied in a normal posture, the nut body of the nut is inserted into the opening of the electrode cover. part is input interrupt, also nut misaligned Ya If it is supplied in a posture not normal orientation, etc., since the flange portion abuts against the nut, it is possible to reliably prevent welding of nuts not normal posture.

Also, since the electrode cover is provided with a flange, when polishing the lower end surface of the upper electrode, the electrode cover is removed from the upper electrode and polished. The electrode cover can be easily attached by locking its flange to the outer periphery of the lower end surface of the upper electrode, and when replacing the upper electrode, remove the electrode cover from the upper electrode and attach it to the newly set upper electrode. With the same electrode cover, the flange is locked to the outer periphery of the lower end surface of the upper electrode,
Easy to install. That is, the electrode cover can be used repeatedly when polishing and replacing the upper electrode, so that the cost can be reduced. Furthermore, the attachment and detachment of the electrode cover and the holding to the upper electrode can be easily performed via the O-ring.
Can be.

According to a third aspect of the present invention, a nut is supplied from a nut feeder to a workpiece interposed between a lower electrode and a lower electrode, and the upper electrode is driven downward by a lifting drive means. When the electrode is lowered to the welding position and immediately before welding, the height position of the upper electrode is determined by the position detection determination means by the position detection determination means through the detected member connected to the upper electrode. It is detected whether it is within the range. In other words, according to the nut abnormality detection device of this nut welding welding machine,
Since the height position detection determining means for detecting whether or not the upper electrode is within the predetermined height range is provided, it is possible to reliably prevent welding of a nut having an abnormal posture.

In addition, an electrode cover detachably fitted to the upper electrode, the lower end of which has a flange fixed to the outer peripheral portion of the lower end surface of the upper electrode and a nut body of the nut. an opening capable of accommodating the fitting shape, is provided with the electrode cover having a guiding tapered surface comprising a large diameter as the lower formed on the inner peripheral portion of the opening, fitted to the upper electrode, the upper electrode a flange portion When the upper electrode is polished or replaced, the electrode cover can be used repeatedly . Further, the as with claim 1, the height position of the upper electrode corresponding to the supply position of the nut in the weld just before state out correctly, the welding of nuts not normal posture through the height position detection determination unit It can be reliably prevented.

According to a fourth aspect of the present invention, in the nut abnormality detecting apparatus for a nut welding welder, the output of the height position detecting and judging means is received, and when it is within the predetermined height range, the welding machine is instructed to execute welding. In addition, when the nut is not in the predetermined height range, the control means for activating the alarm means is provided, so that the nut can be welded only when the nut is in a normal position and posture, and other positional deviation or In the case of a bad posture, it is detected that the height position of the upper electrode is not within the predetermined height range, and welding is not performed. In other words, it is possible to reliably prevent the defective welding of the nut from appearing. Further, when it is determined that the height position of the upper electrode is not within the predetermined height range, the alarm means is activated, so that the normal operation is performed. Without leaving the nuts supplied in a non-
You can remove that nut.

[0031] In the nut anomaly detector nut welding Welding machine according to claim 5, since provided the fine adjustment mechanism for finely adjusting the height position of the detected member relative to the upper electrode, when polishing the upper electrode, The height position of the detected member can be finely adjusted by the amount of shortening the electrode by the polishing, and the height position of the detected member can be finely adjusted even when the size of the nut is changed. .

[0032] In the nut anomaly detector nut welding Welding machine according to claim 6, test and a detected member which is connected to the upper electrode, the height position of the upper electrode through the object to be detected member
Height position detecting means including an encoder means for outputting, and receiving the output of the height position detecting means, the height position of the upper electrode in a state immediately before welding in which the upper electrode is lowered to the welding position is within a predetermined height range. since there is provided a first determination means for determining whether, by the height position detection means can detect the height position of the upper electrode, the first determining means, the upper electrode is lowered to the welding position welding In the immediately preceding state, it is possible to determine whether or not the height position of the upper electrode is within a predetermined height range, so that only nuts having a normal position and posture are securely welded, and nuts having a misalignment or a bad posture. Can be reliably prevented from being welded.

In addition, an electrode cover detachably fitted to the upper electrode, the lower end of which has a flange portion which is engaged with the outer peripheral portion of the lower end surface of the upper electrode and a nut body portion of the nut. Since an electrode cover having an opening that can be accommodated in a fitting shape and a tapered guide surface formed on the inner peripheral portion of the opening and having a larger diameter as it goes down is provided, the upper electrode is formed as in claim 3. If the fitting and the flange are brought into contact with the lower end of the upper electrode , the upper electrode can be used. Even if the upper electrode is polished or replaced, the electrode cover can be used repeatedly .

[0034] via the electrode cover, the height position detecting means, the height position of the upper electrode corresponding to the supply position of the nut can be detected in accurately, by the first determination means for receiving the output of the height position detection means Therefore, it is possible to reliably determine whether or not the upper electrode is within a predetermined height range. Therefore, it is necessary to reliably weld only nuts having a normal position and posture, and to perform welding of nuts having a misalignment or a bad posture. Therefore, it is possible to reliably prevent the occurrence of defective welding of the nut .

According to a seventh aspect of the present invention, in the nut abnormality detecting device for a welding machine for nut welding, the output of the first determining means is received, and when it is within the predetermined height range, the welding machine is instructed to perform welding. Further, when the height is not within the predetermined height range, the control means for operating the alarm means is provided, so that in a state immediately before welding in which the upper electrode is lowered to the welding position,
It is possible to reliably weld only when the nut is in a normal position and posture, and in other misalignment or in a bad posture, it is detected that the height position of the upper electrode is not within the predetermined height range. Since welding is not performed, defective welding of the nut can be reliably prevented from appearing. Further, when it is determined that the height position of the upper electrode is not within the predetermined height range, the alarm means is activated, so that the nut supplied in an abnormal posture is not left as it is,
You can remove that nut.

[0036] In the nut anomaly detector nut welding Welding machine according to claim 8, the height position of the detected member with respect to the upper electrode is provided with the fine adjustment mechanism for fine adjustment, when polishing the upper electrode The height position of the detected member can be finely adjusted by the amount that the electrode is shortened by the polishing,
In addition, the height position of the detected member can be finely adjusted even when the size of the nut is changed.

In the nut abnormality detecting device for a nut welding welder according to the ninth aspect , the output of the height position detecting means receives the output of the height position of the upper electrode when the nut is welded immediately after the welding. Receiving the output of the second determination means, and if the height is within the set height range, outputs a welding completion command,
When the height is not in the set height range, the control means for activating the alarm means is provided, so that the nut state immediately after welding can be detected, so that defective welding of the nut can be prevented as much as possible. Further, if the second determination means determines that the height position of the upper electrode in the state immediately after welding of the nut is not within the set height range, the alarm means is activated. Can be removed without leaving the nut.

According to a tenth aspect of the present invention, in the nut abnormality detecting device for a nut welding welder, the height position detecting means determines an origin height position of the upper electrode from a height position of the upper electrode lowered to the lower limit position. Since there is an origin position setting means for setting, after polishing the upper electrode, after replacing the upper electrode, and further, when an error occurs in the height position of the detected member, the origin position setting means, The origin height position of the electrode can be set accurately.

That is, since the height position of the upper electrode is detected by the height position detecting means with reference to the origin height position, the first determining means and the second determining means receiving the output of the height position detecting means. The means and the control means receiving the output of the first judgment means or the second judgment means can be reliably operated.

[0040]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a nut abnormality detecting device and method for a nut welding upper electrode cover according to the present invention. In this embodiment, as shown in FIG. 4, a case will be described in which a square nut N having a welded part n formed at a lower end portion in an outwardly projecting shape is welded to a workpiece W.

First, the nut welding machine Y will be described. As shown in FIGS. 1 and 2, in the welding machine Y for nut welding, an air cylinder (not shown) is built in the welding machine main body 1 in an inverted manner, and a piston rod 2 of the air cylinder projects downward. The guide rod 3 is provided in the vicinity of the piston rod 2. The lower ends of the piston rod 2 and the guide rod 3 are provided with a pair of upper and lower support members
Are mounted horizontally, and a column-shaped mounting member 6 for mounting an energizing rod is mounted horizontally at the tip of the pair of support members 4 and 5.

A vertical through-hole 6a is provided in the vicinity of the distal end of the mounting member 6, and an energizing rod 7 is inserted and mounted in the through-hole 6a. A cylindrical upper electrode 8 is detachably attached to the lower end of the energizing rod 7. The upper electrode 8 includes a heat-resistant O-ring 23.
The upper electrode cover 20 is attached via (see FIG. 3). Further, the pair of upper and lower support members 4, 5 are provided with flange portions 4a, 5a outward in the horizontal direction, and these flange portions 4a, 5a are connected by a plurality of bolts (not shown). A connecting member 31 is fixed to the lower surface of the flange portion 5 a of the lower supporting member 5, and a connecting rod 30 described later is configured to interlock with the upper electrode 8 via the connecting member 31. A lower electrode 9 is provided so as to face the upper electrode 8. A work W is set on the upper end surface of the lower electrode 9, and a nut N is welded to the work W. A guide pin 9a made of an insulating material, which is inserted into the screw hole of the nut N and guides the nut N, is provided upright on the lower electrode 9 (see FIG. 8).

First, the upper electrode cover 20 and the upper electrode 8 to which the upper electrode cover 20 is attached will be described.
As shown in FIG. 3, the upper electrode cover 20 has a substantially cylindrical electrode cover body 21 and a heat-resistant O-ring mounted in an annular groove 22 formed in the inner peripheral surface of the electrode cover body 21. 23 are provided. The electrode cover body 21
Is provided at its lower end with an inward flange 24 which is locked to the lower end of the upper electrode 8 and an opening 20a which can accommodate the nut body of the nut N in a loose fit. A lower annular tapered surface 25 for guiding the nut, which gradually increases in diameter from the opening 20a to the lower inner periphery of
Are formed. The upper electrode cover 20 is configured to be detachably attached to the upper electrode 8 via an O-ring 23.

Further, the upper portion of the upper electrode cover 20 is formed to have a larger diameter than the lower portion, and an upper annular tapered surface 26 for guiding the upper electrode is formed on the inner peripheral portion of the upper end, the diameter of which increases toward the upper side. An annular shallow groove 27 is formed from the lower end of the upper tapered surface 26 to the axial center.
The upper electrode 8 is formed with a circular hole 8a at the axial center portion from the lower end to a substantially central portion in the axial direction, and further contracts from the upper end to a substantially central portion in the axial direction as it goes down. A diameter attachment hole 8b is formed, and the upper electrode 8 is configured to be attached to the lower end of the current-carrying rod 7 of the welding machine Y via the attachment hole 8b.

Next, the nut abnormality detecting device 10 provided in the nut welding welding machine Y will be described. Figure 1
As shown in FIG. 2, the nut abnormality detecting device 10 includes a connecting member 31, a connecting rod 30 and a fine adjustment mechanism 6 on the upper electrode 8.
Linked via the 0 and the detection plate 48 (corresponding to the subject knowledge member) is disposed on a side surface of the welding machine main body 1 to be detected plate 48
A height position detection / judgment mechanism 40 for detecting the height position of the upper member electrode 8 through the interface and a fine adjustment mechanism 60 for finely adjusting the height position of the detection plate 49 with respect to the upper electrode are provided.
Further, as shown in FIG.
Receives an output from the height position detection / judgment mechanism 40, and when the height position detection / judgment mechanism 40 detects that the nut N is in a normal position and posture, sends a welding execution command signal. A control unit 70 (corresponding to a control device) is provided which outputs an output signal, turns on an error indicator lamp 71 when it is detected that the nut N is not in a normal position and posture, and activates a warning buzzer 72.
The error indicator lamp 71 and the warning buzzer 72 correspond to a warning unit.

Next, the height position detection / judgment mechanism 40, the fine adjustment mechanism 60, the detected plate 48, and the like will be described. A substantially Z-shaped connecting member 3 in which two L-shaped steels are fixed back to back.
The screw portion 32 of the connecting rod 30 is inserted into the upper horizontal portion 33 of the first connecting rod 30, and the connecting rod 30 is fixed to the connecting member 31 by a pair of upper and lower double fixing nuts 34 with the upper horizontal portion 33 interposed therebetween. A horizontal board 41 of a height position detection / judgment mechanism 40 is attached to the upper end of the connecting rod 30. That is, the screw portion 32 of the connecting rod 30 is
A horizontal substrate 41 is fixedly attached to the connecting rod 30 by a pair of upper and lower fixing nuts 36 through washers 35.

The connecting rod 30 on the horizontal substrate 41
Guide shafts 42, 43 are erected at positions near both sides of the welding machine. These guide shafts 42, 43 move up and down to two long and short guide cylinders 45, 46 with linear bearings attached to the side surface of the welding machine body 1. Is inserted as possible. Further, a detection support plate 47 is provided upright at the front end portion of the upper surface of the horizontal substrate 41, and the detection support plate 47 has an elongated hole 47a extending from a substantially central portion in the vertical and longitudinal directions to a portion near the upper end. A bolt member 61 with a head is vertically disposed on the side of the detection support plate 47 on the horizontal substrate 41, and the bolt member 61 is attached to the horizontal substrate 41 so as to be rotatable and unable to move up and down. I have. This bolt member 61
Is screwed into a screw hole 48b provided in a horizontal portion 48a of the detection plate 48 having an L shape in a front view. This detected plate 4
8, a vertical portion 48c is disposed close to the detection support plate 47, and is provided with a pin 49 implanted below the detected plate 48 and a screw of a fixing handle 50 screwed on the upper portion of the detected plate 48. The portion 50a is inserted into the elongated hole 47a so as to be vertically movable.

At the upper end of the detected plate 48, a mirror plate 5 for reflecting incident light from an optical sensor 51 having a light emitting portion and a light receiving portion attached at a predetermined height on the side surface of the welding machine body 1 is provided.
The detected portion 52 having the second portion 2a is integrally provided (see FIG. 5), and the height position detecting / determining mechanism 40 is mainly composed of the optical sensor 51 and the mirror 52a, and is used when the nut N is normally welded. The mirror 52a moves the predetermined height range h including the reference height position K based on the height position of the mirror 52a.
The configuration is such that the output signal of the optical sensor 51 is turned ON only when it is at (see FIG. 8). On the side surface of the detected plate 48, an acute angle reference positioning projection 54 projecting toward the reference positioning arrow 53 imprinted on the guide cylinder 45 is provided. The fine adjustment mechanism 60 is composed of a bolt member 61 with a head and a screw hole 48b of a horizontal portion 48a of the detection plate 48. The plate to be detected 48 is raised and lowered via the bolt portion 63 of the bolt member 61 with a portion and the screw hole 48b, and the detected portion 52 at the upper end of the plate to be detected 48 is moved.
The vertical position with respect to the optical sensor 51 can be finely adjusted.

Next, a control system of the welding machine Y for nut welding will be described. As shown in FIG. 6, the control unit 70 of the welding machine Y for nut welding includes a nut feeder 80, an optical sensor 51 for detecting nuts, a solenoid valve 91 for pressurized cylinder, and a controller 9 for driving the welding machine.
0, an error indicator light 71, a warning buzzer 72, and a reset button 74 are connected. Next, the nut abnormality detection control executed by the control unit 70 will be described with reference to the flowchart of FIG.
It should be noted that the symbols Si (i = 1, 2, 3,...)
・) Indicates each step.

After the nut N is supplied by the nut feeder 80 onto the work W set on the lower electrode 9,
An operation start signal is input from the nut feeder 80 to the control unit 70 (S1). Next, a head lowering signal is output from the control unit 70 to the solenoid valve 91 for the pressurized cylinder, the cylinder is driven, the piston rod 2 is driven down, the upper electrode 8 is lowered, and the lower end of the upper electrode cover 20 is connected to the nut. N contacts (S2). Next, it is determined whether or not the nut N is set to a normal position and a normal posture based on whether or not the detection signal of the optical sensor 51 is ON (S3). That is, by detecting whether the height position of the upper electrode 8 is within the predetermined height range h including the reference height position K by the height position detection / determination mechanism 40, the nut N is moved to a normal position. It is determined whether the subject is in a normal posture.

The detection signal of the optical sensor 51 is ON, and the nut N is in a normal position and in a normal posture (see FIG. 8A).
Is confirmed, the welding start signal is output to the welding machine driving controller 90, and the welding of the nut N to the workpiece N is started (S4). Next, whether or not the welding is completed is determined based on a signal from the controller 90 (S5). When the welding is completed, the process returns to S1.
The following is repeated. On the other hand, as a result of the determination in S3, when the detection signal of the optical sensor 51 is OFF, the nut N is not in a normal position or has a bad posture [(B), (C), (D), and FIG. (E), (F)], the error indicator lamp 71 is turned on and the warning buzzer 72
Is activated and an abnormality is notified (S6). Next, a head lift signal is output from the control unit 70 to the solenoid valve 91 for the pressurized cylinder, the cylinder is driven, the piston rod 2 is driven upward, and the upper electrode 8 is driven upward (S7). After the upper electrode 8 is lifted, the worker removes the nut N and turns on the reset button 74 (S
8), a nut supply command is issued to the nut feeder 80 to supply the nut, and S1 is repeated.

Next, the operation of the nut abnormality detecting device 10 of the nut welding machine Y will be described. First, the nut feeder 8 is placed on the work W interposed between the lower electrodes 9.
0 supplies the nut N. Next, the upper electrode 8 with the upper electrode cover 20 is driven downward through the piston rod 2 by driving of the cylinder, and the upper electrode cover 2
0 contacts the nut N. As shown in FIG.
When the nut N is supplied to a normal position in a normal posture, the nut N is inserted into the opening 20a of the upper electrode cover 20.
And the upper surface of the nut N contacts the lower end of the upper electrode 8. At the same time, the connecting member 3 is connected to the upper electrode 8.
The detection plate 48 connected via the fine rod 1 and the connecting rod 30 to the fine adjustment mechanism 60 is integrally lowered, and the incident light from the optical sensor 51 of the height position detection determination mechanism 40 is detected by the detection plate 48. When the optical sensor 51 is turned on after being reflected by the mirror plate 52a of the section 52, it is detected that the height position of the upper electrode 8 is within the predetermined height range h, and the control unit 7
From 0, a welding execution command signal is output to the welding machine driving controller 90, and the welding machine Y welds the nut N to the workpiece W.

On the other hand, when the nut N is supplied in a state where the nut N is not in the normal position and posture, when the upper electrode 8 is driven downward, the detection of the nut N described below is performed. That is, as shown in FIG. 8B, when the nut N is not supplied, the upper electrode cover 2 of the upper electrode 8 is not covered.
0 comes into contact with the upper surface of the workpiece W and is located below the predetermined height range, the detection signal of the optical sensor 51 of the height position detection / determination mechanism 40 is OFF, and the upper electrode 8 It is detected that the height position is not within the predetermined height range h,
No command signal for welding execution is output from the control unit 70, the error indicator lamp 71 is lit, and the warning buzzer 7
2 is activated. When the warning buzzer 72 is operated, the operator checks the presence or absence of the nut N to confirm that the nut N is not present, and then the nut N is supplied from the nut feeder 80.

As shown in FIG. 8C, when the nut N is supplied to a position shifted from the normal position, the lower end of the upper electrode cover 20 is moved by the lower drive of the upper electrode 8. Since the upper electrode 8 is in contact with the upper surface of the upper electrode N and the upper electrode 8 is not further lowered, the height position of the upper electrode 8 is located above the predetermined height range h. The optical sensor 51 is OFF, and it is detected that the height position of the upper electrode 8 is not within the predetermined height range h, the error indicator light 71 is turned on, and the warning buzzer 72
Is activated, and no command signal for performing welding is output. When the warning buzzer 72 is operated, the operator checks the state of the nut N, removes the nut N in the bad posture from the work W, and then supplies another nut N from the nut feeder 80.

As shown in FIG. 8D, when the nut N is supplied in a slanted posture, the upper electrode 8
When the lower electrode is driven downward, the lower end of the upper electrode cover 20 contacts the upper end of the nut N, and the height position of the upper electrode is located above the predetermined height range h. Is not turned on, it is detected that the height position of the upper electrode 8 is not within the predetermined height range h, the error indicator lamp 71 is turned on, the warning buzzer 72 is activated, and the welding execution command signal is output. Not done. (E) and (F) of FIG.
As shown in the figure, when the nut N is supplied in an upside-down orientation, the lower end of the upper electrode cover 20 abuts on the welded portion n of the nut N, and the height position of the upper electrode 8 is predetermined. It is located above the height position range h, and the optical sensor 51 of the height position detection / determination mechanism 40 is not turned on, and it is detected that the height position of the upper electrode 8 is not within the predetermined height position range h, The error indicator lamp 71 is turned on, the warning buzzer 72 is activated, and the command signal for executing welding is not output.

Therefore, only when the nut is in the normal position at the normal position shown in FIG. 8A, the height position of the upper electrode 8 is set within the predetermined height range h by the height position detection / determination mechanism 40. It is detected that there is, welding is performed, and in other misalignments and defective postures, it is detected that the height position of the upper electrode 8 is not within the predetermined height range h, and welding is not performed.
Since the error indicator lamp 71 is turned on and the warning buzzer 72 is operated, the supply posture of the nut N can be detected before welding, and only the nut N having the normal posture at the normal position is welded. Since the welding of the nut N in the defective posture is not performed, it is possible to prevent the defective welding of the nut N from appearing. Further, by providing a fine adjustment mechanism 60 for finely adjusting the height position of the interlocking rod 30 with respect to the upper electrode 8, when the electrode is polished, the plate to be detected is reduced by an amount corresponding to the shortening of the electrode by the polishing. The height position of the detection plate 48 can be finely adjusted even when the size of the nut N is changed.

Further, by mounting the O-ring 23 in the annular groove 22 on the inner peripheral surface of the electrode cover main body 21 of the upper electrode cover 20, the upper electrode cover 20 can be easily mounted on the upper electrode 8, and the upper electrode 8 can be easily mounted. Since the upper electrode cover 20 can be easily removed from the upper electrode 8, when the lower end surface of the upper electrode 8 is polished, the upper electrode cover 20 is removed and polished, and after being polished, it can be easily attached to the upper electrode 8 and held. ,
When the upper electrode 8 is replaced, the upper electrode cover 20 can be detached from the upper electrode 8 and the same upper electrode cover 20 can be mounted on the newly set upper electrode 8.
Thereby, when replacing the upper electrode 8, the upper electrode cover 20 can be used repeatedly, and the cost can be reduced. In addition, since the flange 24 is provided at the lower end of the upper electrode cover 20 and the lower annular tapered surface 25 for guiding the nut is formed on the inner periphery of the lower end, the nut N is corrected to a normal position and a normal posture to a certain extent. Electrode cover 20
And the normal welding efficiency of the nut N can be increased. Further, since a standard electrode which is usually used can be used as the upper electrode 8,
Cost can be reduced. Since a commercially available sequencer can be used as the control unit 70, cost can be reduced.

Next, based on the block diagram of FIG. 9, illustrating the nut anomaly detector 10 for nut welding welder Y A variant with a. In addition, the nut abnormality detecting device 10
Is the same as in the above embodiment, and the description thereof will be omitted, and the same members will be denoted by the same reference numerals. The nut welding welder Y A of this variant, without provided the control unit 70 in the embodiment, the welding machine drive controller 90, and a foot踏式switch 92 and the pressing cylinder solenoid valve 91 It is connected, and furthermore, an optical sensor 51 for nut detection is connected via a relay 93. next,
Based on the flowchart shown in FIG. 10 will be described nut abnormality detection control executed by welder drive controller of the nut welding welder Y A. In the flowchart, reference symbol Si (i = 11, 12, 13,...) Indicates each step.

First, when the worker steps on the foot switch 92 to turn it on, the nut N is supplied from the nut feeder 80 onto the work W interposed between the lower electrodes 9 (S1).
1). Next, a head lowering signal is output from the welding machine controller 90 to the solenoid valve 91 for the pressurizing cylinder to drive the cylinder. The lowering drive of the piston rod 2 lowers the upper electrode 8, and the upper electrode cover 20 is moved to the nut N. Contact is made (S12). Next, it is determined whether or not the nut N is in a normal position and has a normal posture based on whether or not the detection signal of the optical sensor 51 is ON (S1).
3). That is, by detecting whether the height position of the upper electrode 8 is within the predetermined height range h by the height position detection determination mechanism 40, it is determined whether the nut N is in a normal position and in a normal posture. Is determined.

When it is confirmed that the optical sensor 51 is ON and the nut N is in the normal posture (see FIG. 8A), a welding start signal is output, and the welding of the nut N to the workpiece W is started. It is started (S14). Next, it is determined whether or not the welding has been completed (S15).
After the foot switch 92 is turned off (S16), the process returns and S11 and the subsequent steps are repeated. On the other hand, when the detection signal of the optical sensor 51 is OFF in S13,
The nut N is not in a normal position or has a bad posture [FIG.
(B), (C), (D), (E), and (F)], a head lift signal is output from the welding machine driving controller 90 to the pressurizing cylinder solenoid valve 91, and the cylinder is moved. Then, the piston rod 2 is driven up to drive the upper electrode 8 up (S17). Thereafter, the foot switch 92 is turned off (S18), and the worker returns after removing the nut N which is not in a normal position or has a bad posture, and the process is repeated again from S11.

[0061] According to the nut welding welder Y A of this modification, since the worker to perform welding by ON · OFF foot踏式switch 92 while looking at the supply position of the nut N on the work W, the control Unit 70 and error indicator light 71,
Since the warning buzzer 72, the reset button 74, and the like are not required, the structure can be simplified, and the operation can be performed easily.

Next, an upper electrode 8A with an upper electrode cover 20A according to a first alternative embodiment will be described with reference to FIG. As shown in FIG. 11, the upper electrode cover 20A of the upper electrode 8A with the upper electrode cover has a substantially cylindrical electrode cover body 21A and an annular groove 22A recessed on the inner peripheral surface of the electrode cover body 21A. Heat resistant O to be attached
A substantially cylindrical synthetic resin insulating material having a ring 23A and an inward flange 95a locked at the lower end to the lower end of the upper electrode 8 and interposed between the upper electrode 8 and the electrode cover body 21A. A member 95 is provided, and an opening 20b is formed at the lower end of the upper electrode cover 20A. The electrode cover main body 21A is provided at its lower end with an inward flange 24A that is locked to the lower end of the upper electrode 8, and the lower end of the flange 24A is located below the opening 20b. A lower annular tapered surface 25A for guiding the nut, which gradually becomes larger in diameter, is formed. Then, the upper electrode cover 20
A is configured to be detachably attached to the upper electrode 8 via an O-ring 23A. Further, the flange 24A of the electrode cover main body 21A is provided with the flange 9 of the insulating member 95.
5a is locked.

The upper portion of the electrode cover body 21A of the upper electrode cover 20A is formed to have a larger diameter than the lower portion, and the upper end portion is formed with an upper annular tapered surface 26A for guiding the upper electrode, the diameter of which increases toward the upper side. ing. The upper and lower ends of the outer peripheral portion of the upper electrode cover 20A are chamfered.
The upper electrode 8 is formed with a circular hole 8a at the axial center portion from the lower end to a substantially central portion in the axial direction, and further contracts from the upper end to a substantially central portion in the axial direction as it goes down. A mounting hole 8b having a diameter is formed, and the upper electrode 8 is configured to be mounted on the lower end of the current-carrying rod 7 of the welding machine via the mounting hole 8b (see FIG. 1). Upper electrode 8A with upper electrode cover 20A of the first alternative embodiment
Is mounted on the lower end of the current-carrying rod 7 of the welding machine Y for nut welding described in the above embodiment. The nut welding machine to which the upper electrode 8A with the upper electrode cover according to the other embodiment is attached does not include the nut abnormality detecting device 10 according to the above embodiment. That is, in this alternative embodiment, the supply position and the supply posture of the nut N are detected based on the energized state of the upper electrode 8A with the upper electrode cover and the lower electrode 9, so that the nut abnormality detecting device 10 is not required. is there.

Next, the operation of the upper electrode 8A with the upper electrode cover according to the first alternative embodiment will be described. First,
The nut N is supplied from the nut feeder 80 onto the work W interposed between the lower electrodes 9, and thereafter, the cylinder is driven, the piston rod 2 is driven downward, and the upper electrode 8 is lowered. As shown in FIG. 12A, when the nut N is in a normal position and in a normal posture, the upper portion of the nut N enters the opening 20b of the upper electrode cover 20A, and the upper end of the nut N contacts the upper electrode 8. The upper electrode 8 contacts the lower end.
And the lower electrode 9 is energized through the nut N and the work W. In this state, a voltage is applied to the upper electrode 8 and the lower electrode 9, and the welding of the nut N to the workpiece W is performed.

As shown in FIG. 12B, when the nut N is not supplied, the lower end of the upper electrode cover 20A comes into contact with the work W and no electricity is supplied. In this case,
No welding is performed. As shown in FIG. 12C, when the nut N is at a position shifted from the normal position, the lower end of the upper electrode cover 20A comes into contact with the upper surface of the nut N and no current is supplied. Also in this case, no welding is performed. As shown in FIG. 12F, when the nut N is turned upside down, the lower end of the upper electrode cover 20A comes into contact with the welded portion n of the nut N and no electricity is supplied. Also in this case, no welding is performed.

According to the nut welding machine having the upper electrode 8A with the upper electrode cover according to the first alternative embodiment, the nut abnormality can be accurately detected without the need for the nut abnormality detector 10. , The structure can be simplified, and it can be provided at low cost. Further, by attaching an O-ring 23A to the annular groove 22A on the inner peripheral surface of the electrode cover main body 21A of the upper electrode cover 20A,
A can be easily attached to the upper electrode 8 and the upper electrode cover 20A can be easily removed from the upper electrode 8, so that when polishing the lower end surface of the upper electrode 8, the upper electrode cover 20A is polished.
A is removed and polished, and after polishing, the upper electrode cover 20A can be easily attached to and held on the upper electrode 8, and when the upper electrode 8 is replaced, the upper electrode cover 20A is removed from the upper electrode 8, Newly set upper electrode 8
To the same upper electrode cover 20A.
Thus, when replacing the upper electrode 8, the upper electrode cover 20A can be used repeatedly, and the cost can be reduced.

Next, a description will be given of a modification in which the main embodiment and the first alternative embodiment are partially changed. 1) In the main embodiment, when the nut abnormality is detected by the nut abnormality detecting device 10, when the nut is abnormal, the welding can be stopped before energization, so that it is not necessary to perform the KCF treatment or the like on the electrode cover. An inexpensive steel electrode cover can be applied without forming an insulating layer on the electrode cover. 2] It is also possible to apply the nut abnormality detecting device 10 to the nut welding welding machine provided with the upper electrode 8A with the upper electrode cover in the above-mentioned another embodiment, and to detect the nut abnormality by the nut abnormality detecting device 10.

Next, a description will be given of a nut welding machine Y1 according to a second alternative embodiment. However, the same components as those in the above embodiment are denoted by the same reference numerals, and the description thereof will be omitted. The nut welding welder Y1 of the second alternative embodiment does not include the height position detection / judgment mechanism 40 including the optical sensor 51 and the mirror 52a of the main embodiment and the fine adjustment mechanism 60. As shown in FIG.
1 and a magnetic encoder device 100 (corresponding to a height position detecting means) composed of a detector 102.

The control unit 110 (corresponding to a control device) of the nut abnormality detecting device 10A has a height position of the upper electrode 8 in a state immediately before welding in which the upper electrode 8 is lowered to the welding position. A first determining means for determining whether or not the height is within a predetermined height range; and a second determining means for determining whether or not the height position of the upper electrode 8 in a state immediately after welding of the nut N is within a set height range. When the height position of the upper electrode 8 is within a predetermined height range in response to the output of the determination means and the first determination means, a command is issued to the nut welding welding machine Y1 to perform welding. When the height position is not within the set height range, the control means activates the alarm means, receives the output of the second determination means, and outputs a head lift command when the height position of the upper electrode 8 is within the set height range. When not in the specified height range Includes a control means for actuating an alarm means, program origin height position setting means for setting the origin height position are respectively stored. In the control unit 110, the magnetic encoder device 10
The height signal from 0 is read, and the height position of the upper electrode 8 is calculated. The error indicator lamp 71 and the warning buzzer 72 correspond to a warning unit.

[0070] The description attached to the nut abnormality detection device 10A. The connecting rod 3 is provided on the upper horizontal portion 33 of the connecting member 31.
No. 0 screw part 32 is inserted, and the connecting rod 30 is fixed to the connecting member 31 by a pair of upper and lower double fixing nuts 34 sandwiching the upper horizontal part 33, and a horizontal substrate 105 is mounted on the upper end of the connecting rod 30. Have been. That is, the screw portion 32 of the connecting rod 30 is inserted into a through hole (not shown) provided in the horizontal substrate 105, and the horizontal substrate 105 is fixedly attached to the connecting rod 30 by a pair of upper and lower fixing nuts 36. I have. A pair of guide shafts 103 are erected at positions near both sides of the connecting rod 30 on the horizontal substrate 105, and these guide shafts 103
The guide shafts 104 are vertically movably inserted into a pair of guide cylinders 104 with linear bearings attached to the side surface of the welding machine body 1 via fixing plates 107.
The upper end of 3 is connected to the connecting member 106.

The distal end of the shaft to be detected 101 is connected to the center of the lower surface of the connecting member 106. The shaft to be detected 101 extends downward from the connecting member 106, and moves inside the cylindrical detecting body 102 so as to be able to move up and down. The detector 102 is fitted so as to move up and down integrally with the upper electrode 8.
07 is fixedly attached to a central portion of the electronic component 07 via a bracket 102a. On the surface of the detected shaft 101, a striped detected portion (not shown) in which a large number of magnetic materials and non-magnetic materials are alternately wound is provided. A receiver for receiving a magnetic signal is provided, and the received magnetic signal is converted into a height signal and output to the control unit 110.

Next, a control system of the nut welding machine Y1 will be described. As shown in FIG. 15, the control unit 110 of the welding machine Y1 for nut welding includes a nut feeder 80 and a magnetic encoder device 100.
, A pressure cylinder solenoid valve 91, a welding machine driving controller 90, an error indicator light 71, a warning buzzer 72, a reset button 74, a keyboard 108 for inputting nut data, and an origin height position setting start Button 109 is connected. Next, the nut abnormality detection control executed by the control unit 110 will be described with reference to the flowchart of FIG. still,
Symbol Si in the flowchart (i = 1, 2, 3,...)
Indicates each step.

First, the work W set on the lower electrode 9
When the nut N is supplied by the nut feeder 80 and an operation start signal is input to the control unit 110 from the nut feeder 80 (S21), a head lowering command is then sent from the control unit 110 to the solenoid valve 91 for the pressure cylinder. Output (S22),
The upper electrode 8 is driven downward by the cylinder 1a. At the same time, the height signal from the magnetic encoder device 100 is read (S23), and the height position H of the upper electrode 8 immediately before welding is calculated (S24).

When the height position H of the upper electrode 8 just before welding is calculated, it is determined in S25 whether the nut N is set to a normal position and in a normal posture.
That is, as shown in FIG. 18B, the height position H of the upper electrode 8 falls within a predetermined height range (H ₁ −α) to (H ₁ + α) including the first reference height position H _1. It is determined whether there is. The height position of the upper electrode 8 is within a predetermined height range (H ₁ −
α) to (H ₁ + α), and when it is confirmed that the nut N is in a normal position and in a normal posture, a signal of a welding execution command is output to the welding machine driving controller 90 (S26). ), Welding of the nut N to the work W is started.

On the other hand, as a result of the determination in S25, the height position H of the upper electrode 8 is located in a predetermined height range (H ₁ -α) to (H ₁ + α) including the first reference height position H _1. If not, the nut N is not in a normal position or has a bad posture [(B), (C), (D), (E) in FIG.
(Refer to (F)), the error indicator lamp 71 is turned on and the warning buzzer 72 is activated to notify the abnormality (S3).
1) Next, a head raising signal is output from the control unit 110 to the solenoid valve 91 for the pressurized cylinder (S32), and the upper electrode 8 is raised. Thereafter, the operator removes the nut N and presses the reset button 74. When it is turned on (S33), a nut supply command is issued to the nut feeder 80 to supply the nut, and S21 and subsequent steps are repeated.

In S26, when a command to execute welding of the nut N to the work W is output, a height signal is read from the magnetic encoder device 110 (S27). The height position H of the upper electrode 8 at that time is calculated (S28), and FIG.
As shown in the figure, the height position H of the upper electrode 8 is in the set height range (H ₂ −β) to (H ₂ +) including the second reference height position H _2.
β) is determined (S29), and when it is determined that the height position H of the upper electrode 8 is within the set height range and the nut N is securely welded, the head lift signal is sent to the pressure cylinder. The signal is output to the solenoid valve 91 (S30), the upper electrode 8 rises, and then returns, and S21 and subsequent steps are repeated. Note that the first height reference position H ₁ and the second height reference position H ₂ are determined by the control unit 110 by the origin height position H ₀ set by the origin height position setting described later.
Α and β are set from the nut data input to the control unit 110 in advance.

[0077] On the other hand, in S29, the Most determined Do the height H is set height range of the upper electrode 8, the welding for the workpiece W of the nut N is determined to be insufficient, an error indicator 71 The lamp is lit and the warning buzzer 72 operates to notify the abnormality (S31), and a head lift signal is output to the solenoid valve 91 for the pressurized cylinder (S32).
When the upper electrode 8 rises and the operator removes the nut N and turns on the reset button 74 (S33),
Returning, a nut supply command is issued to the nut feeder 80 to supply the nut, and S21 and the subsequent steps are repeated.

Next, the origin height position setting executed by the control unit 110 will be described with reference to the flowchart of FIG. Note that reference numerals Si (i = 1, 2, 3,...) In the flowchart indicate each step. First, the origin height position setting button 109 is turned on.
By performing N, a reference height position setting start signal is input to the control unit 110 (S41), and then nut data previously input by the keyboard 108 is read (S42). When the data of the nut N is read, a head lowering command is output (S43), and the upper electrode 8
At the same time, the upper electrode cover 20 is driven downward.

Next, it is determined whether or not the height position H of the upper electrode 8 is at the head lowering limit position (S44). If it is determined that the head is at the head lowering limit position, the pulse counter of the magnetic encoder device 100 is determined at S45. The circuit is reset, and at this head lowering limit position, the origin height position of the upper electrode 8 is set to H ₀ = 0. Then, in S46, based on the origin height H ₀ and the nut data, first reference height position H ₁ and the second reference height position H ₂ is calculated, then, the head-up signal is output (S47 ),
The height signal is read from the magnetic encoder device 100 (S48), and if it is the head ascending limit position (S49),
Setting the origin height position H ₀ is completed. Incidentally, in this origin height position setting, the workpiece W is performed still set, the origin height H ₀ is the height of the upper electrode 8 shown in FIG. 18 (A).

Next, the nut welding machine Y described above is used.
The operation of the first nut abnormality detecting device 10A will be described. First, the nut N is supplied by the nut feeder 80 onto the work W interposed between the lower electrodes 9. Next, the upper electrode 8 with the upper electrode cover 20 is driven downward by the cylinder via the piston rod 2, and the upper electrode cover 20 comes into contact with the nut N. As shown in FIG. 8A, when the nut N is supplied to a normal position in a normal posture, the upper side of the nut N enters the opening 20a of the upper electrode cover 20, and the upper electrode 8 The upper surface of the nut N contacts the lower end.

When the upper electrode 8 is driven to descend, the shaft to be detected 101 also descends integrally, and the control unit 110, from which the height signal from the magnetic encoder 100 is read, is used. 8
Is calculated. This height position H is within a predetermined range (H ₁ −α) to (H ₁ +) including the first reference height position H _1.
α), the control unit 11
From 0, a welding execution command signal is output to the welding machine driving controller 90, and the welding machine Y welds the nut N to the workpiece W.

On the other hand, when the nut N is supplied in a state where it is not in the normal position and posture, when the upper electrode 8 is driven to descend, the detection of the nut N described below is performed. That is, as shown in FIG. 8B, when the nut N is not supplied, the upper electrode cover 2 of the upper electrode 8 is not covered.
0 comes into contact with the upper surface of the workpiece W and is located below the predetermined height range, it is detected that the upper electrode 8 is not in the predetermined height range, and the control unit 110 issues a welding execution command signal. Is not output and the error indicator 71
Is turned on, and the warning buzzer 72 is activated.

As shown in FIG. 8C, when the nut N is supplied to a position shifted from the normal position, the lower end of the upper electrode cover 20 is moved by the lowering drive of the upper electrode 8. Since the upper electrode 8 comes into contact with the upper surface of N and the upper electrode 8 is not further lowered, the height position H of the upper electrode 8 is located above the predetermined height range (H ₁ −α) to (H ₁ + α). That is, it is detected that the height position H of the upper electrode 8 is not within the predetermined height range, the error indicator lamp 71 is turned on, the warning buzzer 72 is activated, and the welding execution command signal is not output. Is activated.

As shown in FIG. 8D, when the nut N is supplied in an obliquely inclined posture, the upper electrode 8
During the downward drive, the lower end of the upper electrode cover 20 abuts on the upper end of the nut N, and the height position H of the upper electrode is located above the predetermined height range (H ₁ −α) to (H ₁ + α). That is, it is detected that the height position H of the upper electrode 8 is not within the predetermined height range, the error indicator lamp 71 is turned on, the warning buzzer 72 is operated, and the welding execution command signal is not output. As shown in FIGS. 8E and 8F, when the nut N is supplied in an upside down orientation, the lower end of the upper electrode cover 20 is attached to the welded portion n of the nut N. The height position H of the upper electrode 8 is in a predetermined height position range (H ₁ −
α) to (H ₁ + α), it is detected that the height position H of the upper electrode 8 is not within the predetermined height range, the error indicator lamp 71 is turned on, the warning buzzer 72 is activated, No command signal for welding execution is output.

Therefore, only when the nut is in the normal position at the normal position shown in FIG. 8A, the upper electrode 8 is in the predetermined height range (H ₁ -α) to (H ₁ + α). When the detected position is detected, welding is performed, and other misalignments and defective postures occur, the height position H of the upper electrode 8 is set to a predetermined height range (H
₁₋ α) to (H ₁ + α), it is detected that no welding is performed, the error indicator lamp 71 is lit, and the warning buzzer 72
Is activated, so that the feeding posture of the nut N can be detected before welding, and only the nut N having the normal posture at the normal position can be welded, and the nut N having the misalignment and the bad posture can be welded. Since there is no such, it is possible to prevent defective welding of the nut N from appearing. Furthermore, the height position H of the upper electrode 8 in the state immediately after the welding with a welded nut N is a set height range including the second reference height position H ₂ (H _2-beta) ~
Since it is determined whether or not (H ₂ + β), it is possible to confirm whether or not the nut N has been securely welded. Therefore, welding failure of the nut N that occurs at the time of welding can also be reliably detected. .

Further, by mounting the O-ring 23 in the annular groove 22 on the inner peripheral surface of the electrode cover main body 21 of the upper electrode cover 20, the upper electrode cover 20 can be easily mounted on the upper electrode 8, and the upper electrode 8 can be easily mounted. Since the upper electrode cover 20 can be easily removed from the upper electrode 8, when the lower end surface of the upper electrode 8 is polished, the upper electrode cover 20 is removed and polished.
The upper electrode 8 can be easily attached to the upper electrode 8 and held, and the upper electrode cover 20 is removed from the upper electrode 8 when the upper electrode 8 is replaced. The electrode 8 also has the same upper electrode cover 20.
Can be easily attached by locking the flange 20a to the outer peripheral portion of the lower end surface of the upper electrode 8. Thereby, when replacing the upper electrode 8, the upper electrode cover 20 can be used repeatedly, and the cost can be reduced.

Further, since the flange portion 24 is provided at the lower end of the upper electrode cover 20 and the lower annular tapered surface 25 for guiding the nut is formed on the inner periphery of the lower end, the nut N is corrected to a somewhat normal position and normal posture. Thus, the nut N can be accommodated in the opening 20a of the upper electrode cover 20, and normal welding efficiency of the nut N can be increased. Further, since a standard electrode which is generally used can be used as the upper electrode 8, the cost can be reduced.

Next, a description will be given of a welding machine Y2 according to a third embodiment. However, this welding machine Y2 is a partial modification of the welding machine Y2 of the second alternative embodiment, and the same parts are denoted by the same reference numerals and description thereof is omitted. . As shown in FIG. 19, the nut abnormality detecting device 10B includes the detected member 1 connected to the horizontal substrate 120.
12 and a detector 113 fixedly attached to a fixing plate 118, which is an optical sensor type encoder device 100A including a detector having a light emitting unit and a light receiving unit (not shown).
(Corresponding to a height position detecting means). Guide shafts 116 and 117 are erected at positions near both sides of the connecting rod 30 on the horizontal substrate 120, and these guide shafts 116 and 117 are two long and short guide cylinders with linear bearings attached to the side surface of the welding machine main body 1. It is inserted into the bodies 114 and 115 so as to be able to move up and down.

A light blocking member 111 having a U-shaped cross section is provided on the front end surface of the detected member 112 erected on the horizontal substrate 120.
Is fixedly mounted, and on the rear end surface of the detected member 112,
A striped detection part with a number of reflection parts spaced at predetermined intervals (not shown)
The optical signal received by the light receiving unit is converted into a height signal via a pulse counter circuit built in the optical sensor type encoder device 100A, and output to the control unit 110. It should be noted that the control system of the nut welding welder Y2 of the third alternative embodiment is different from the control system of the nut welding welder Y1 of the second alternative embodiment in that an optical sensor type encoder device is used instead of the magnetic encoder device 100. 100A is provided, and the flowchart of the nut abnormality detection control and the flowchart of the setting of the origin height position of the upper electrode are substantially the same as those of the second alternative embodiment, so that the description thereof is omitted. The nut welding machine Y2 according to the third alternative embodiment has the same operation and effect as the nut welding welder Y1 according to the second alternative embodiment.

[Brief description of the drawings]

FIG. 1 is a front view of a nut welding welder provided with a nut abnormality detection device according to an embodiment.

FIG. 2 is a side view of the welding machine for nut welding of FIG. 1;

FIG. 3 is an enlarged vertical sectional view of an upper electrode with an upper electrode cover.

FIG. 4 is a perspective view of a nut.

FIG. 5 is a partial perspective view of a height position detection determination mechanism of the nut abnormality detection device.

FIG. 6 is a block diagram of a control system of the welding machine for nut welding.

FIG. 7 is a flowchart of nut abnormality detection control.

FIG. 8 is an explanatory view showing a height position detection state of an upper electrode with an upper electrode cover.

FIG. 9 is a block diagram of a control system of a nut welding machine including a nut abnormality detecting device according to a modification.

FIG. 10 is a flowchart of nut abnormality detection control in the nut welding machine of FIG. 9;

FIG. 11 is a longitudinal sectional view of an upper electrode with an upper electrode cover according to a first different embodiment.

FIG. 12 is an explanatory diagram showing a state of detecting conduction by the upper electrode with the upper electrode cover of FIG. 11;

FIG. 13 is a front view of a welding machine according to a second alternative embodiment.

FIG. 14 is a side view of the welding machine shown in FIG. 13;

FIG. 15 is a block diagram of a control system of a welding machine for nut welding according to a second alternative embodiment.

FIG. 16 is a flowchart of nut abnormality detection control according to the second alternative embodiment.

FIG. 17 is a flowchart of setting an origin height position of an upper electrode.

FIG. 18 is an explanatory diagram showing a state of detecting a height position of an upper electrode.

FIG. 19 is a front view of a welding machine for welding according to a third different embodiment.

[Explanation of symbols]

 Y, Y1, Y2 Nut welding welder N Nut W Work 2 Piston rod 8 Upper electrode 9 Lower electrode 10, 10A, 10B Nut abnormality detection device 20, 20A Upper electrode cover 20a, 20b Opening 21, 21A Electrode cover body 22 , 22A Annular groove 23, 23A O-ring 24, 24A, 95a Flange 40 Height position detection / judgment mechanism 48 Detected plate 60 Fine adjustment mechanism 70, 110 Control unit 95 Insulation member 100 Magnetic encoder 100A Optical sensor encoder 101 Detected shaft 112 Detected member

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yasuhiro Narahara 1844, Iida, Hachihonmatsu-cho, Higashihiroshima-shi, Hiroshima Pref. Inside of the Otodo Works, Hachihonmatsu Plant (56) References Real Opening Sho 53-115130 (JP, U) Real Opening Sho 57-102488 (JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) B23K 11/30 B23K 11/24

Claims (10)

(57) [Claims] An upper electrode cover externally fitted to an upper electrode of a welding machine for nut welding, comprising: an electrode cover main body; and an insulating member for insulating the electrode cover main body from the upper electrode. An electrode cover which is detachably mounted is provided. A flange portion which is locked to an outer peripheral portion of a lower end surface of the upper electrode and an opening which allows only a nut body portion of the nut to be loosely fitted at a lower end portion of the electrode cover. And a guide taper surface having a larger diameter toward the lower side is formed in an inner peripheral portion of the opening, and an annular groove is recessed in an inner peripheral surface of the electrode cover main body. An upper electrode cover for nut welding, wherein an O-ring is mounted and the electrode cover is held on the upper electrode via the O-ring. 2. An upper electrode cover externally fitted to an upper electrode of a nut welding welder provided with a height position detecting means for detecting a height position of the upper electrode, wherein the upper electrode cover is detachably attached to the upper electrode. An electrode cover is provided, and a lower end portion of the electrode cover is provided with a flange portion which is locked to an outer peripheral portion of a lower end surface of the upper electrode, and an opening portion which can accommodate only the nut main body portion of the nut in a loose fit state. A guide taper surface having a larger diameter is formed in the inner peripheral portion of the opening downward, an annular groove is formed in the inner peripheral surface of the electrode cover, and a heat-resistant O-ring is attached to the annular groove. An upper electrode cover for nut welding, wherein an electrode cover is held on an upper electrode via an O-ring. 3. A nut welding machine comprising an upper electrode, a lower electrode opposed to the upper electrode, and a lifting drive means for driving the upper electrode up and down, wherein the nut welding machine is detachably fitted to the upper electrode. An electrode cover, a lower end portion of which has a flange portion which is locked to an outer peripheral portion of a lower end surface of the upper electrode, an opening capable of accommodating only the nut main body of the nut in a loose fit state, and An electrode cover having a guide taper surface formed on the periphery and having a larger diameter as it goes downward, a member to be detected connected to the upper electrode, and a state immediately before welding when the upper electrode is lowered to a welding position. A height error detecting means for detecting whether or not the height position of the upper electrode is within a predetermined height range via the detected member; Detection device. 4. An output of the height position detecting and judging means, and when it is within the predetermined height range, instructs the welding machine to execute welding, and when it is not within the predetermined height range, an alarm means The nut abnormality detecting device for a welding machine for nut welding according to claim 3, further comprising control means for operating the nut. 5. The nut abnormality detecting device for a welding machine for nut welding according to claim 3, further comprising a fine adjustment mechanism for finely adjusting a height position of the detected member with respect to the upper electrode. 6. A nut welding machine comprising an upper electrode, a lower electrode opposed to the upper electrode, and an elevating drive means for elevating and lowering the upper electrode, wherein the nut welding machine is detachably fitted to the upper electrode. An electrode cover, a lower end portion of which has a flange portion which is locked to an outer peripheral portion of a lower end surface of the upper electrode, an opening capable of accommodating only the nut body portion of the nut in a loose fit state, An electrode cover having a guide taper surface formed on a peripheral portion and having a larger diameter toward the lower side; a detected member connected to the upper electrode; and detecting a height position of the upper electrode via the detected member. Do
A height position detecting means including an encoder means, receiving an output of the height position detecting means, and a height position of the upper electrode in a state immediately before welding in which the upper electrode is lowered to the welding position is within a predetermined height range. A nut abnormality detecting device for a nut welding welder, comprising: first determining means for determining whether or not the nut is abnormal. 7. Receiving an output of said first judging means, when it is within said predetermined height range, instructs a welding machine to execute welding, and when not within said predetermined height range, activates an alarm means. The nut abnormality detecting device for a welding machine for nut welding according to claim 6, further comprising control means for causing the nut to be welded. 8. The nut abnormality detecting device for a nut welding welder according to claim 6, further comprising a fine adjustment mechanism for finely adjusting a height position of the detected member with respect to the upper electrode. 9. A second determining unit that receives an output of the height position detecting unit and determines whether the height position of the upper electrode in a state immediately after welding of the nut is in a set height range, Control means for receiving an output of the second determination means, outputting a welding completion command when the welding position is within the set height range, and activating an alarm means when not within the set height range. The nut abnormality detecting device for a welding machine for nut welding according to claim 7, characterized in that: 10. The apparatus according to claim 1, wherein said height position detecting means has an origin position setting means for setting an origin height position of the upper electrode from a height position of the upper electrode lowered to the lower limit position. The nut abnormality detecting device for a welding machine for nut welding according to claim 7.