JP2001212676A - Projection welding apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely prevent welding under the defective condition by precisely detecting the defects such as a figure of a weld nut, positing, and quality. SOLUTION: In the apparatus, an air duct 15c which makes an air flow out from the bottom end side of a movable electrode 15 is installed. When pressurizing the movable electrode 15 in a weld nut 9, pressure air is supplied into the air duct 15c and the air pressure is detected by a pneumatic sensor 17. From the pressure abnormality, when a misaligned nut and a figure abnormality nut are detected, a nut removing apparatus 19 is operated to remove the misaligned nut and the figure abnormality nut from the vicinity of a welding position. A new weld nut are supplied and disposed on the work 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a claw-shaped projection (projection) on the back surface side as a welding portion.
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection welding apparatus for welding a part to be welded (hereinafter, referred to as a projection part) such as a welding nut to a work, and more specifically, a function of detecting a mounting failure in advance when welding a projection part to a work. And a projection welding apparatus comprising the same.

[0002]

2. Description of the Related Art Conventionally, as a device for welding a welding nut of this kind to a workpiece, there is known a projection welding device for clamping a welding nut between a fixed electrode and a movable electrode, passing an electric current, and welding by a resistance welding method. Have been. That is,
As shown in FIG. 10, a work 2 is arranged on a fixed electrode 1 and a welding nut 3 supplied from a nut feeder is provided.
Is fitted to a guide pin 4 provided at the center of the fixed electrode 1, and the welding nut 3 is pressed by the movable electrode 5 which moves up and down.
By supplying a current between the electrodes 1 and 5, the welding nut 3
The four claw-shaped projections 3a provided on the back surface of the workpiece are melted and welded to the work 2. In addition,
A water circulation channel 6 is provided inside the movable electrode 5 so that heat generated by welding is cooled by water.

However, the welding nut 3 supplied from the nut feeder is not always set at a correct position, and may be set at a position deviating from the guide pin 4 (nut displacement). In such a case,
If you do not notice this defect and weld it as it is,
Unusable defective products will be produced.

Therefore, conventionally, as a means for solving such inconvenience, a nut detecting device described in JP-A-05-188157 has been provided. In the detection device described in the publication, as shown in FIG. 11, a welding nut 3 is provided on the other side of the work (plate material) 2 in such a manner that the welding nut 3 has a common axis with an insertion hole 2 a provided in the work 2. A guide pin 7 provided with an air passage 7a is inserted into the female screw hole 3b of the welding nut 3 which is positioned and arranged, and compressed air is injected from an outlet 7b provided on a peripheral surface of the guide pin 7. Then, the injection resistance at this time is detected by the air pressure sensor 8, and when the pressure is high, the injection port 7b is blocked by the inner peripheral wall of the female screw hole 3b, so that it is determined that the welding nut 3 is present. When it is low, the ejection port 7b is in the open state, so that it is determined that there is no welding nut 3.

[0005]

However, in the prior art described in the above-mentioned publication, although the presence or absence of the welding nut 3 can be reliably detected, as shown in FIG. Can not be detected, the welding nut 3 is securely mounted by welding, but the front and back are opposite, that is, the claw-shaped projection 3
There has been a problem that occurrence of a situation in which a is upward (body abnormality) cannot be avoided. Therefore, as shown in FIG. 2B, the user does not notice that the welding nut 3 is set in the opposite direction, and if automatic welding is performed as it is, the welding is performed in a state where the current density is insufficient. As a result, a defective product in which the nut is easily removed is manufactured. In particular, this type of welding defect in the frame of a motor vehicle is very dangerous.

The present invention has been made in view of the above-described circumstances, and provides a projection welding apparatus having a function of detecting in advance a form abnormality of a welding nut when welding a projection component such as a welding nut to a work by welding. It is intended to be.

[0007]

According to the first aspect of the present invention, a work is supplied between a fixed electrode and a movable electrode, and a work is provided on a portion to be welded of the work on a back surface. A projection component having a to-be-welded part and having a through hole that escapes from the front surface to the back surface,
The present invention relates to a projection welding apparatus for welding the projection component and the work in a state of being sandwiched between the fixed electrode and the movable electrode, wherein at least a distal end of the movable electrode on the fixed electrode side has an opening at an end face thereof. Is provided with an air passage having the other opening on the side surface thereof, and when the movable electrode comes into contact with the projection component and is welded, supplies compressed air to the air passage provided in the movable electrode. Air supply means, an air pressure sensor for detecting the air pressure in the air passage, and welding control means for controlling the stop / execution of the welding based on the detection value of the air pressure sensor. And

According to a second aspect of the present invention, there is provided the projection welding apparatus according to the first aspect, wherein an opening of the end surface of the movable electrode and an axis are provided at an end surface of the fixed electrode on the movable electrode side. It is characterized in that guide pins for positioning are provided by inserting the projection components, which are substantially opposed to each other, through the through holes.

According to a third aspect of the present invention, there is provided the projection welding apparatus according to the first or second aspect, wherein the projection component set at or near the welded portion of the workpiece is connected to the welded portion or the workpiece. In addition to the projection component removing means for removing from the vicinity thereof, the welding control means detects the detection value of the air pressure sensor when the projection component is set upside down on the welded portion of the work. When you receive
By controlling the driving of the projection component removing means,
It is characterized in that the above-mentioned projection parts turned upside down are removed.

According to a fourth aspect of the present invention, there is provided the projection welding apparatus according to the first or second aspect, wherein the projection component set at or near the welded portion of the work is connected to the welded portion or the workpiece. A projection component removing unit that removes from the vicinity thereof is provided, and the welding control unit is configured to detect a value detected by the air pressure sensor when the projection component is set at a position to be welded on the workpiece with a displacement. When you receive
By controlling the driving of the projection component removing means,
The invention is characterized in that the projection component that is displaced is removed.

According to a fifth aspect of the invention, there is provided the projection welding apparatus according to the first or second aspect, wherein the pressure detected by the air pressure sensor is lower than a first reference value set in advance. The invention is characterized in that the welding control means controls the driving of the projection component removing means to remove the set projection component.

[0012] The invention according to claim 6 is the third invention.
In the projection welding apparatus according to 4 or 5, after the welding control means controls the driving of the projection component removing means to remove the set projection component, a new welding position is provided at the workpiece to be welded. It is characterized in that it is configured to perform control for setting the above-mentioned projection parts.

[0013] Further, the invention according to claim 7 is the third invention.
According to the projection welding apparatus of the fourth or fifth aspect, the projection component removing means is configured to remove the projection component by electromagnetic attraction.

[0014] The invention described in claim 8 is the third invention.
4. The projection welding apparatus according to item 4 or 5, wherein the projection component removing means is configured to remove the projection component by jet air.

According to a ninth aspect of the present invention, there is provided the projection welding apparatus according to the first aspect, wherein the projection component is a welding nut.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. The description will be specifically made using an embodiment. FIG. 1 is a side view showing a configuration of a projection welding apparatus according to a first embodiment of the present invention, and FIG. 2 is a schematic enlarged view showing a main part of the welding apparatus schematically and enlarged. FIG. 3 is a cross-sectional view, FIG. 3 is an explanatory diagram for explaining an operation of a nut feeder constituting a main part of the welding device, and FIG. 4 is a flowchart showing an operation processing procedure executed by a control unit of the welding device. FIG. 5 and FIG. 6 are views provided for explaining the operation of the control unit (detection operation of a malpositioned nut / abnormal nut) and show various setting states of the nut at the time of welding. FIG. 5A shows a state in which the welding nut 9 is set upside down, FIG. 5B shows a state in which the welding nut is set with a displacement, and FIG. The nutless state in which the nut 9 is not set, and FIG. 4D is a diagram showing a state in which the welding nut 9 is set in a normal state and a normal position, respectively. Further, FIG.
FIG. 3 is a diagram for explaining the operation of a nut removing device that constitutes a main part of the welding device.

The projection welding apparatus according to this embodiment relates to an apparatus for welding and mounting a welding nut 9 to an automobile part. As shown in FIG. 1 or FIG. A lower frame 11 and an upper frame 12 that project forward in a corresponding manner, a fixed electrode 14 attached to the lower frame 11 and on which a work 13 is placed, and a movable electrode that is attached to the upper frame 12 and that can move up and down. An electrode 15, a nut feeder 16 for supplying and arranging the welding nut 9 to a welding position on the work 13, and an air pressure for measuring an air pressure of an air passage 15 c provided below the movable electrode 15 as described later. A sensor 17; a controller 18 for judging a position defect / abnormal state of the welding nut 9 based on an output of the air pressure sensor 17; 18 based instruction to the, is schematically configured from the nut removal device 19 for removing the misregistration nut abnormal figure nut from the vicinity of the welding position.

The fixed electrode 14 is, as shown in FIG.
It is vertically fixed to the tip of a fixed electrode mounting portion 11a fixed to the lower frame 11. A concave portion 20 is provided at the center of the upper end surface of the fixed electrode 14, and the concave portion 20 is provided with a welding nut 9 through a spring 21.
A guide pin 22 for positioning is projected so as to be vertically movable.

An air cylinder 23 is attached to the tip of the upper frame 12, and a movable body 24 is connected to a piston of the air cylinder 23 and is driven up and down. A movable electrode 15 is vertically attached to the movable body 24. Fixed. The movable electrode 15 and the fixed electrode 14 are arranged opposite to each other with a common axis, and a current is applied between the fixed electrode 14 and the movable electrode 15 through an electric circuit (not shown), so that projection is performed as described later. It is configured to perform welding.

As shown in FIG. 2, the movable electrode 15 includes an electrode tip portion 15a and a shank portion 15b, and a cooling water passage 15c is formed inside the shank portion 15b except for a lower portion.
Is provided. In addition, an air passage 15c for air cooling and for detecting the state of the welding nut 9 is formed inside a lower portion of the movable electrode 15 (that is, a region from a lower portion of the shank portion 15b to an electrode tip portion 15a). Shank part 15b
The air inlet of the air passage 15c is provided on the side surface of the air passage 15c, and the outlet of the air passage 15c is provided on the bottom surface of the electrode tip portion 15a. The air hose 26 is connected.

As shown in FIG. 1, the air hose 26 is connected to a three-way pipe joint 27, is connected to the regulator 28 from the pipe joint 27, and is connected to the air source 30 through the supply pipe 29 from the pipe joint 27. It is connected. An air pressure sensor 17 is provided in the middle of the pipe joint 29.
The air pressure sensor 17 has, for example, a piezoelectric sensor or the like, and has an air passage 15 c formed under the movable electrode 15.
Detects the air pressure P in the chamber and detects the detected pressure signal (electric signal) P
Is output.

The control section 18 in this example has a software configuration having a CPU (central processing unit) and memories such as a ROM and a RAM. The CPU controls the welding nut 9 in accordance with a control program read from the ROM. work
It is determined whether or not the nut has been set correctly.If the result of the determination is that the nut is set correctly, projection welding is performed. An operation of removing from the vicinity of the welding position on 13 is executed.

That is, when the welding nut 9 is welded, the control unit 18 determines whether the first reference pressure PL or the second reference pressure PH (PH> PL) set in advance and the air pressure sensor 1
By comparing with the detected pressure signal P inputted from 7,
It is determined whether or not the welding nut 9 supplied and arranged on the work 13 is set normally. As a result of the judgment, when the welding is set normally, a welding current is applied between the fixed electrode 14 and the movable electrode 15 to execute projection welding. On the other hand, when the nut is set abnormally, the nut removing device 19 is driven to remove the malpositioned nut / abnormal nut from the vicinity of the welding position on the work 13.

As shown in detail in FIG. 3, the nut feeder 16 is provided obliquely above the fixed electrode 14, and is provided with a fixed chute 16a for lowering the welding nut 9 and supplying it to a welding location on the work 13. A movable chute 16b which is slidably (slidably) fitted around the outer periphery of the fixed chute 16a to dispose the welding nut 9 received from the fixed chute 16a at a welding location on the work 13; A pair of connecting plates 16c, 16c attached to one end of each of 16a;
It is composed of a piston 16d and a cylinder 16e provided between these connecting plates 16c, 16c.

The distal end of the movable chute 16b is curved so as to be directed substantially horizontally so that the welding nut 9 is supplied neatly in the vertical direction. A hole 16f is provided. When the movable chute 16b slides down and extends, the drop hole 16f is disposed immediately above the guide pin 22 provided on the upper end surface of the fixed electrode 14 and has a common axis. It has been made like that.

By the way, such a nut feeder 16
However, the situation where the welding nut 9 is set at the welding position of the work 13 in a state where the front and back are opposite, that is, with the claw-shaped projection 9a facing upward, cannot be completely eliminated.

As shown in FIG. 2, the nut removing device 19 includes an air cylinder 19a, a piston 19b reciprocating in the air cylinder 19a, a long piston rod 19c connected to the piston 19b, An electromagnetic coil 19d is inserted into the rod 19c and magnetized by electrical control. When the piston rod 19c advances by receiving a force from the piston 19b, its tip reaches just above the welding nut 9 set on the work 13.

Next, referring to FIGS. 3 to 7, the operation of the control unit (detection / removal operation of a defectively positioned nut / abnormal nut) in the welding apparatus of this embodiment will be described. First, a work (for example, a frame member of an automobile) 13 is placed on the fixed electrode 14, and a guide pin 22 protruding from an upper end surface of the fixed electrode 14 is fitted into a bolt insertion hole formed at a nut welding position of the work 13. (Fig. 2
reference). Next, as shown in FIGS. 3 (a) and 3 (b), the movable chute 16b of the nut feeder 16 is slid down, and then the welding nut 9 is lowered along the movable chute 16b. 16f drop hole
Then, it is dropped into the guide pins 22 on the upper surface of the fixed electrode 14. Then, the female screw hole 9b of the welding nut 9 is fitted to the guide pin 22 and positioned at the nut welding position of the work 13.

Next, an air passage 15 below the movable electrode 15 is supplied from an air source 30 via a supply pipe 29 and an air hose 26.
While supplying air to c, the movable electrode 15 is lowered,
The welding preparation is completed by contacting the welding nut 9 on the fixed electrode 14 (step SP1 in FIG. 4).

When the preparation for welding is completed, the control unit 18 proceeds to step SP2, and determines whether or not the air pressure P detected by the air pressure sensor 17 exceeds a first reference value PL set in advance.

As shown in FIG. 5 (a), when the front and back of the welding nut 9 are set upside down, four claw-like projections 9a provided on the back side of the welding nut 9 are provided. Since the lower end surface of the movable electrode 15 hits, a gap 26 is formed between the movable electrode 15 and the welding nut 9, and air flows out from the gap 26. In this case, the air pressure sensor 17 also has a relatively low pressure value Pa ( PL> Pa) is detected. Control unit 1
8 compares the detected pressure signal Pa input from the air pressure sensor 17 with the first reference pressure PL in step SP2. In the example of FIG. 9A, since the determination result of PL> Pa is obtained (that is, it is detected that the welding nut 9 is abnormally set), the control unit 18 proceeds to the process of step SP3. As shown in FIG. 7, the nut removing device 19 is driven to move the abnormally shaped nut 9 to the work 13.
From the vicinity of the welding position on the top.

That is, the controller 18 raises the movable electrode 15 and separates it from the welding nut 9 (FIG. 7).
(A)). Next, by driving the piston 19b, the piston rod 19c is energized to the electromagnetic coil 19d while moving forward until the tip end thereof is located immediately above the abnormal state nut 9 set on the work 13. Then, the piston rod 19c is magnetized. As a result, the abnormal state nut 9 is magnetically attracted to the tip of the magnetized piston rod 19c as shown in FIG. When the abnormal state nut 9 is attracted to the tip of the piston rod 19c, the control unit 18 drives the piston 19b to move the piston rod 19c backward. When the abnormal state nut 9 is sufficiently separated from the welding position of the work 13, the electromagnetic coil 19d is turned off, and the abnormal state nut 9 is dropped from the tip of the piston rod 19c.

When the abnormal nut 9 is removed in this way, the control unit 18 returns to step SP1 and
A new welding nut 9 is supplied from the nut feeder 16 and the welding preparation is repeated.

Next, as shown in FIG. 2B, when the welding nut 9 is set at a position deviated from the guide pin 22, there is no welding nut 9 immediately below the air passage 15c. Is largely opened and the air resistance becomes relatively small, so that the air pressure sensor 17 detects a relatively low pressure value Pb (PL> Pb). Control unit 18
In step SP2, a comparison is made between the detected pressure signal Pb input from the air pressure sensor 17 and the first reference pressure PL. In the example of FIG. 3B, since the determination result of PL> Pb is obtained (that is, it is detected that the welding nut 9 is set abnormally), the control unit 18 proceeds to the process of step SP3. According to the above-described procedure, the nut removing device 19 is driven to remove the poorly-positioned nut from the work 13.
From the vicinity of the welding position on the top.

When the nut 9 is removed in this manner, the control unit 18 returns to step SP1 and
A new welding nut 9 is supplied from the nut feeder 16 and the welding preparation is repeated.

Next, as shown in FIG. 6C, when the welding nut 9 is in a nutless state in which it is not set on the guide pin 22, the lower end surface of the movable electrode 15 is
Is directly in contact with the air passage 15 of the movable electrode 15.
c is closed and the air resistance becomes high.
In the air pressure sensor 17, a relatively high pressure value Pc (Pc>
PH> PL) is detected.

The controller 18 first detects the detected pressure signal P input from the air pressure sensor 17 in step SP2.
c is compared with the first reference pressure PL. Figure (c)
In the example of the above, since the determination result of Pc> PL is obtained, the control unit 18 proceeds to the process of step SP4, and this time, the detection pressure signal Pc input from the air pressure sensor 17 and the second
Is compared with the reference pressure PH.

In the example shown in FIG. 3C, since the determination result of Pc> PH is obtained (that is, it is detected that the welding nut 9 has not been set), the control unit 18 immediately proceeds to step SP1. Then, a new welding nut 9 is supplied from the nut feeder 16 and the welding preparation is repeated.

Next, as shown in FIG. 3D, when the positioning and the orientation of the welding nut 9 are normal, the female screw hole 9b of the welding nut 9 is fitted in the guide pin 22, and The claw-shaped projection 9 a contacts the work 13, and the lower end surface of the movable electrode 15 contacts the surface of the welding nut 9. In this state, the air in the air passage 15c of the movable electrode 15 causes the gap between the female screw hole 9b and the guide pin 22 and the gap between the claw-shaped protrusion of the welding nut 9 and the work 13 to pass. I'll pass through,
The air resistance is larger than that in the state where the front and back are reversed in FIG. 5A and the position is misaligned in FIG.
It is smaller than in the nutless state of (d).

Therefore, the air pressure sensor 17 detects an appropriate pressure value Pd (PH>Pd> PL). The control unit 18 first compares and determines the detected pressure signal Pd input from the air pressure sensor 17 with the first reference pressure PL in step SP2. In the example of FIG. 6C, Pc>
Since the PL determination result is obtained, the control unit 18 proceeds to the process of step SP4, and this time compares and determines the detected pressure signal Pd input from the air pressure sensor 17 with the second reference pressure PH.

In the example shown in FIG. 3C, a determination result of PH> Pc is obtained. That is, in this state, since the mounting state and the mounting position are normal, the process proceeds to step SP5, in which a welding current flows between the movable electrode 15 and the fixed electrode 14 (welding is executed). As a result, the welding nut and the work 13 are strongly welded at the positions of the claw-shaped projections.

As described above, according to the configuration of this example, when welding the welding nut 9 to the work 13 by welding, the welding nut 9
Not only can be detected, but also the reverse set (posture abnormality) of the welding nut 9 can be detected in advance. In addition, even if the position of the welding nut 9 is misaligned or the abnormal shape is generated, the misaligned nut or abnormally shaped nut is automatically removed and a new welding nut is automatically supplied. You don't have to. Therefore, the work flow becomes smoother, and the productivity is improved.

Second Embodiment Next, a second embodiment of the present invention will be described. FIG.
FIG. 7 is a view for explaining the operation of a nut removing device used in a projection welding device according to a second embodiment of the present invention. As shown in FIG. 1A, the nut removing device 31 of this example includes an air cylinder 31a, a piston 31b reciprocating in the air cylinder 31a, and a long piston rod 31 connected to the piston 31b.
c. When the piston rod 31c moves forward by receiving a force from the piston 31b, the same figure (b)
As shown in (1), the distal end portion collides with the side surface of the welding nut 9 set as a position error or an abnormal state on the work 13 to remove the welding nut 9 by mechanical force. With the configuration of this example, substantially the same effects as described in the first embodiment can be obtained.

Third Embodiment Next, a third embodiment of the present invention will be described. FIG.
FIG. 9 is a diagram for explaining the operation of a nut removing device 32 used in a projection welding device according to a third embodiment of the present invention. The nut removing device 32 of this example is configured to blow off the welding nut 9 by blowing air 32a. With the configuration of this example, substantially the same effects as described in the first embodiment can be obtained.

Although the embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and the design may be changed without departing from the scope of the present invention. Is also included in the present invention. For example, projection parts are not limited to welding nuts, electrical contacts,
As long as there are plugs, rings and other protrusions,
The present invention can be applied.

Further, in the above-described embodiment, the nut feeder including the fixed chute and the movable chute is used. However, the present invention is not limited to this. Or any other material may be used. Also, the means for determining the abnormal shape and poor position of the welding nut may be a software configuration or a hardware configuration (control by a sequencer, relay control).

When it is determined that the set welding nut is abnormal in form or defective in position, a message may be displayed on a display device or an alarm may be issued to notify the worker of the abnormality. Although not shown in FIGS. 5 and 6, even in the case of a defective product having an abnormality in the shape of the welding nut 9, an abnormality is detected because a large gap is formed between the movable electrode 15 and the welding nut 9. it can. Further, the nut removing device is not limited to the above-described embodiment.

[0048]

As described above, according to the structure of the present invention, when a vertically asymmetric projection part such as a welding nut is welded to a work, not only can the position of the projection part be detected, but also the position of the projection part can be detected. It is possible to detect in advance the reverse set (posture abnormality) of the projection parts. In addition, even if a position error or abnormal posture of the projection parts occurs, the position error
Since the abnormal projection parts are removed and new projection parts are automatically supplied, the welding work does not have to be stopped immediately. Therefore, the work flow becomes smoother, and the productivity is improved.

[Brief description of the drawings]

FIG. 1 is a side view showing a configuration of a projection welding apparatus according to a first embodiment of the present invention.

FIG. 2 is a schematic enlarged sectional view schematically and enlarged showing a main part of the welding apparatus.

FIG. 3 is an explanatory diagram for explaining an operation of a nut feeder constituting a main part of the welding device.

FIG. 4 is a flowchart showing an operation processing procedure executed by a control unit of the welding apparatus.

5A and 5B are diagrams for explaining the operation of the control unit (detection operation of a malpositioned nut and an abnormally shaped nut), showing various set states of the nut at the time of welding; FIG.
FIG. 7B is a diagram illustrating a state in which the welding nut is set upside down, and FIG.

FIG. 6 is a diagram provided for describing the operation of the control unit (detection operation of a malpositioned nut and an abnormally shaped nut), showing various set states of the nut at the time of welding;
Nutless state where is not set, and (d)
FIG. 4 is a view showing a state in which the welding nut 9 is set in a normal state and a normal position, respectively.

FIG. 7 is a view for explaining the operation of a nut removing device that constitutes a main part of the welding device.

FIG. 8 is a view for explaining an operation of a nut removing device constituting a main part of a projection welding device according to a second embodiment of the present invention.

FIG. 9 is a view for explaining the operation of a nut removing device constituting a main part of a projection welding device according to a third embodiment of the present invention.

FIG. 10 is a schematic longitudinal sectional view for explaining a conventional projection welding apparatus.

FIG. 11 is a schematic longitudinal sectional view for explaining another conventional projection welding apparatus.

FIG. 12 is a diagram for explaining a problem of the conventional technique.

[Explanation of symbols]

9 Welding nut (projection part) 9a Claw-shaped projection (projected portion to be welded) 9b Female screw hole 13 Work 14 Fixed electrode 15 Movable electrode 15a Electrode tip (tip) 15c Air passage 16 Nut feeder 17 Air pressure sensor 18 Control Part (welding control means) 19, 31, 32 Nut removal device (projection component removal means) 19c Piston rod 30 Air source (air supply means) P, Pa, Pb, Pc, Pd Detected pressure signal (detected pressure) PL First Reference pressure (first reference value) PH Second reference pressure (second reference value)

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shoichi Kimura One of 126 Nishishinmachi, Ota City, Gunma Prefecture Toa Kogyo Co., Ltd. (72) Inventor Kazuo Kitajima One of 126 Nishishinmachi, Ota City, Gunma Prefecture Toa Kogyo Inside the corporation

Claims (9)

[Claims] A workpiece is supplied between a fixed electrode and a movable electrode, and a projection component having a welded portion projecting from the back surface and a through-hole extending from the front surface to the back surface is provided at a portion to be welded on the work. A projection welding apparatus for setting and welding the projection component and the work in a state of being sandwiched between the fixed electrode and the movable electrode, wherein at least a distal end portion of the movable electrode on the fixed electrode side has an end face. An air passage having one opening on the side surface and another opening on the side surface thereof is provided. When the movable electrode is brought into contact with the projection component and welded, pressure is applied to the air passage provided on the movable electrode. Air supply means for supplying air; an air pressure sensor for detecting the air pressure in the air passage; and Discontinuation of contact /
A projection welding apparatus comprising: welding control means for controlling execution. 2. The projection component, which is opposed to the end surface of the fixed electrode on the side of the movable electrode, which has the same axis as the opening of the end surface of the movable electrode, is inserted through the through hole. 2. The projection welding apparatus according to claim 1, wherein a guide pin for positioning is provided. 3. The apparatus according to claim 1, further comprising: a projection component removing unit that removes the projection component set at or near the welded portion of the workpiece from the welded location or the vicinity thereof. When the projection component is set to the work to be welded on the workpiece in a reverse direction, when the detection value of the air pressure sensor is received, the drive of the projection component removal means is controlled to control the projection of the projection in the reverse direction. 3. The projection welding apparatus according to claim 1, wherein parts are removed. 4. The apparatus according to claim 1, further comprising: a projection component removing unit configured to remove the projection component set at or near the welded location of the workpiece from the welded location or the vicinity thereof, and the welding control unit includes: When a projection component is set at a position to be welded on the workpiece with a displacement, when a detection value of the pneumatic sensor is received, the drive of the projection component removal means is controlled, and the displacement is performed. 3. The projection welding apparatus according to claim 1, wherein the projection parts are removed. 5. When the detected pressure detected by the air pressure sensor is lower than a preset first reference value, the welding control means controls the driving of the projection component removing means to set The projection welding apparatus according to claim 1, wherein the projection component is removed. 6. The welding control unit controls the drive of the projection component removing unit to remove the set projection component, and then sets the new projection component at a welded portion of the work. The projection welding apparatus according to claim 3, wherein the projection welding apparatus is configured to perform control for causing the projection welding to be performed. 7. The projection component removing means,
6. The projection welding apparatus according to claim 3, wherein the projection component is electromagnetically attracted and removed. 8. The projection component removing means,
6. The projection welding apparatus according to claim 3, wherein the projection component is removed by jet air. 9. The projection welding apparatus according to claim 1, wherein the projection component is a welding nut.