JPH0733469U - Projection / weld nut set position confirmation device - Google Patents

Abstract

(57) [Summary] [Purpose] To prevent the occurrence of defective products in which the weld nut is welded in the wrong position and posture. In a welding device that energizes a weld nut 3 set on a work W placed on a fixed electrode 1 by a movable electrode that is vertically movable, encloses the weld nut 3 and the movable electrode at a lower limit position. A vertically movable ring 10 is provided by being suspended by a supporting means 11. At the upper limit position of the ring, the upper end contact surface 10a contacts the contact surface 4a at the lower end of the upper holder 4. Air was supplied from the air pressure source to the air ejection port 15 of the contact surface 10a, and the pneumatic hose 17 was provided with the pneumatic converter 18. A ring comes into contact with the weld nut that is not correctly set, the air outlet is blocked, the aeroelectric converter detects a pressure change, and the control device 20 interrupts the welding current and gives an alarm.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a welding nut set position confirmation device in a projection welding apparatus in which a weld nut is set on a work placed on a lower electrode, and the upper electrode presses the weld nut to energize and weld.

[0002]

[Prior art]

 Conventionally, for example, with respect to a welding device for a weld nut, the weld nut, which is the object of the welding device, is a small item, and therefore, it is often set by mistake by mistake. Then, even if the set position and posture of the weld nut on the workpiece are changed in this way, they will be welded as they are. As a result, the weld nut is reversed or a defective product with a bad welding position is produced.Because the welding position is bad and the welding force is weak, the weld nut may fall off the work piece with a slight shock in the later process. Since there will be inconvenience, measures against it have been required.

As a countermeasure, for example, a device as shown in FIG. 3 has been tried. In this device, a plate-like work W having bolt holes preliminarily provided at predetermined positions is placed on the fixed-side electrode 1 having a positioning pin 2 projected at the center, and the weld nut 3 is placed on the work W. The positioning pin 2 is guided and set. A movable electrode 51 made of, for example, a CrCu material is attached via a taper shank 5 to a lower portion of the upper holder 4 which can be moved up and down by a fluid pressure cylinder or the like.

A ring 52 made of, for example, S10c material is attached by an interference fit to surround the lower portion of the movable-side electrode 51. The lower end of the ring 52 and the lower end of the movable electrode 51 are flush with each other. Further, a plurality of protrusions 3a are provided at the lower end of the weld nut 3 which is a contact portion with the upper surface of the work W, and is configured so that a welding current can be concentrated and stable and reliable welding can be performed. ing.

In the above configuration, as shown in FIG. 3A, after the weld nut 3 is set on the work W placed on the fixed side electrode by guiding it to the positioning pin 2, the holder 4 is inserted from above. , The movable side electrode 51 is lowered together with the taper shank 5 and brought into contact with the upper surface of the weld nut 3. When a welding current is applied, the welding current is intensively applied between the protrusion 3a and the work W, so that the protrusion 3a is melted and the weld nut 3 is firmly welded to the work W. As described above, when the weld nut 3 is correctly set on the work W, no welding current flows in the ring 52.

Next, as shown in FIG. 3B, when the weld nut 3 is set upside down, the protruding portion 3 a extending in the radial direction of the weld nut 3 forms a ring 52. The welding nut 3 is abutted and a welding current is applied between the protrusion 3a and the ring 52, so that the weld nut 3 is welded to the ring 52 side. This is intended to prevent the occurrence of a defective product such as the weld nut 3 which is reversely attached to the work W.

[0007]

[Problems to be solved by the device]

 However, in this countermeasure device, in order to continue the work, the movable side electrode 51 to which the ring 52 is attached must be replaced, or the wrongly attached weld nut 3 must be removed to polish the lower surface of the ring 52. There is a problem that it must be. In addition, when the weld nut 3 is placed on the work W by being detached from the positioning pin 2 or is placed sideways, the weld nut 3 is similarly welded to the ring 52 side, so that a defective product is generated. However, in order to continue the work, the same post-process as when the weld nut 3 is reversely set is required.

Therefore, there is a problem that reliability is poor, time and economic loss are large, and automation cannot be applied. Therefore, in consideration of the above-mentioned conventional problems, the present invention prevents the generation of defective products even if the position and posture of the weld nut on the workpiece are defective, and allows the work to continue immediately. It is an object of the present invention to provide a set position confirmation device for a projection, weld, and nut, which has little time and economical loss and can be automated.

[0009]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the present invention has an upper electrode and a lower electrode, which are opposed to each other and can be relatively displaced vertically, and a weld nut is placed on a work placed on the lower electrode. In a welding device that sets and welds this weld nut by pressing it with the upper electrode held by the holder and passing electricity, it is possible to move vertically around the upper electrode and include the weld nut in the normal position. A ring having an inner diameter, and a lower limit position regulating means for regulating the lower limit position of the ring at a point where the lower end face of the ring projects downward from the lower end face of the upper electrode by a dimension slightly smaller than the thickness of the weld nut. An appropriate number of air jets connected to an air pressure source, which are provided on the upper contact surface of the ring that contacts the contact surface of the lower end of the holder to regulate the upper limit position of the ring; And atmospherics converter provided in air pressure supply path from the source, was made and a control means for interrupting the alarm and the welding current based on the output of the air-electric converter.

[0010]

[Action]

 First, after setting the weld nut correctly on the work placed on the lower electrode, hold it by the upper electrode relatively from above and apply the welding current, the weld nut will be welded to the predetermined position on the work. . At this time, the ring is supported by the supporting means and remains stationary at the lower limit position, and the contact surface of the ring remains separated from the contact surface of the holder. Therefore, since air is flowing out from the air ejection port and the air pressure in the pneumatic hose is low, the aeroelectric converter does not operate and the welding current is not interrupted.

If the weld nut is not correctly set on the work, the lower end surface of the ring comes into contact with the weld nut or the work when the upper electrode relatively approaches the weld nut. It rises relative to the upper electrode, and the contact surface contacts the contact surface of the holder. Then, the outflow of air is hindered and the air pressure in the pneumatic hose rises. Therefore, the pneumatic converter is activated and the welding current is cut off, and the alarm is activated to notify the malfunction.

[0012]

【Example】

 FIG. 1 is an axial sectional view of an essential part showing an embodiment of the present invention. In FIG. 1, the same reference numerals used in FIG. 3 are the same components having the same operation. In FIG. 1, the left side of the center line shows the movable electrode 6 in the raised state, and the right side shows the lowered state. A lower holder 7 is provided so as to be supported by a lower horn extending from a bed under a column (not shown) of the welding device. The fixed side electrode 1 is fixed and supported in the tapered inner hole of the lower holder 7. A plate-shaped work W is placed on the upper surface 1a of the fixed-side electrode 1, and a positioning pin 2 that can move up and down is provided in the center hole, and a spring 8 is always provided. The positioning pin 2 is urged upward by and the front end of the positioning pin 2 projects to the upper surface 1a of the fixed electrode 1.

Similarly, although not particularly shown, similarly to a normal welding device, a fluid pressure cylinder is provided supported by an arm extending from the upper portion of the column, and the piston rod moves up and down by projecting to the lower portion of the fluid pressure cylinder. It is possible. An upper holder 4 is supported and provided on an upper horn fixed to the lower end of the piston rod. For example, a taper shank 5 made of, for example, Becu material is attached to the inner hole of the upper holder 4 made of BSBM material, and a movable side electrode 6 made of, for example, CrCu material is supported on the lower taper portion of the taper shank 5. It is provided.

The lower end surface 6 a of the movable electrode 6 is a horizontal surface and is in contact with the weld nut 3 so that a welding current is transmitted. A welding current is supplied to the lower holder 7 and the upper holder 4 by an electric wire cable via the lower horn and the upper horn.

Next, as a set position confirmation device 9 for the weld nut 3, first, a ring 10 that surrounds the movable electrode 6 and is vertically movable, for example, made of SUS304, is provided. The lower limit position of the ring 10 is regulated via the support means 11. The support means 11 includes a support plate 12 supported on the stepped portion of the upper holder 4 and a plurality of suspension bolts 14 made of, for example, SU304. The hanging bolt 14 has a hook-shaped lower end, which is fixed to the side surface of the ring 10 by a bolt, and an upper-end side which is vertically movable through a hole formed in the supporting plate 12 and a lower limit position by a nut 13. The ring 10 is suspended while restricting the placement.

Further, when the ring 10 is at the lower limit position, the lower end surface 10a of the ring 10 is set to project downward by a dimension h slightly smaller than the thickness of the weld nut 3 from the lower end surface 6a of the movable electrode 6. Has been done. The inner diameter of the ring 10 is set so as to include the weld nut 3 in the normal position. Further, the upper end surface of the ring 10 is a horizontal contact surface 10b, and the contact surface 4a of the lower end portion of the upper holder 4 is in contact with the contact surface 10b, whereby the upper limit position of the ring 10 is restricted. .

The contact surface 10 b is provided with an appropriate number of air ejection ports 15 facing the contact surface 4 a of the upper holder 4, and each air ejection port 15 is provided with a communication passage 16 provided in the ring 10. Tied with. An air pressure hose 17 from an air pressure source is connected to the communication passage 16, and a pneumatic converter 18 is provided in the middle of the air pressure hose 17. The aerostatic converter 18 outputs a signal to the control device 20 when the pressure of the pneumatic hose rises, and based on this signal, the control device 20 cuts off the welding current and activates an alarm device. It is becoming like this.

Next, the operation will be described. First, as shown in the left half of FIG. 1, the movable electrode is raised, and then the work W is placed on the fixed electrode 1. At this time, since the work W is preliminarily formed with a bolt hole at the welding position of the weld nut 3, the positioning pin 2 is provided with the above bolt hole, and the weld nut 3 is also guided and placed on the work W. To do.

Then, the movable side electrode 6 is lowered by the fluid pressure cylinder, and as shown in the right half portion in FIG. 1, the lower end surface 6 a is brought into contact with and pressed against the upper surface of the weld nut 3, and a welding current is applied to the electrode. Energize. Since the welding current is concentrated on the protrusion 3a while being pressed by the work, the welding nut 3 is melted together with the contact portion of the work W and the weld nut 3 is firmly welded to the work W. The material of the weld nut 3 and the work W is generally mild steel and thus welds to each other. However, since the material of the movable side electrode 6 is CrCu as described above, the weld nut 3 is welded to the movable side electrode 6. Not done.

At this time, since the lower end surface 10a of the ring 10 which is a part of the set position confirmation device 9 is not in contact with anything, the ring 10 is at the lower limit position. The air supplied from the air pressure source by the air pressure hose 17 flows out from the air ejection port 15 via the communication passage 16, so that the air pressure in the air pressure hose 17 is low and the welding current is not interrupted.

Next, when the weld nut 3 is guided upside down by the positioning pin 2 and placed on the work W, the movable electrode 6 is lowered as shown in FIG. Then, the lower end surface 10a of the ring 10 comes into contact with the protrusion 3a of the weld nut 3, so that the ring 10 moves up relative to the movable electrode 6. Then, the contact surface 10b of the ring 10 is brought into contact with the contact surface 4a at the lower portion of the upper holder 4, so that the air ejection port 15 is closed. Since the air pressure in the pneumatic hose 17 rises due to the closing of the air ejection port 15, the pneumatic converter 18 operates to output a signal to the control device 20, interrupt the welding current, and activate the alarm device. It activates and informs of the trouble situation.

Further, the weld nut 3 is placed on the work W by being removed from the positioning pin 2 as shown in FIG. 2B, or the weld nut 3 is placed as shown in FIG. 2C. When the movable side electrode 6 is lowered when it is placed sideways, the lower end surface 10a of the ring 10 abuts on the weld nut 3, so that the ring 10 is attached to the movable side electrode 6. It rises relatively. Then, as in the case of FIG. 2A, the air ejection port 15 is closed by the contact surface 4 a of the upper holder 4.

Even if the weld nut 3 is blown out of the planned welding area, the movable side electrode 6 descends to bring the lower end surface 10 a of the ring 10 into contact with the upper surface of the work W, so The ejection port 15 is closed by the contact surface 4a of the upper holder 4. Therefore, the air pressure in the pneumatic hose 17 rises to activate the pneumatic converter 18, so that the welding current is cut off and the alarm is activated.

Therefore, generation of defective products is prevented in advance. Further, since the welding current is not supplied, the ring 10 is prevented from welding the weld nut 3 which is set by mistake in an unexpected posture or position on the work W, or welding to the work W. The work can be continued immediately if the set position of the weld nut 3 is corrected correctly. This has the effect of preventing defective products, improving reliability, and eliminating economic losses.

Similarly, since the ring 10 is not welded to the weld nut 3 or the like that is set by mistake, the work can be continued immediately if the ring 10 is set correctly, and therefore, there is an effect that it can also correspond to the automated projection. . Further, since air pressure is used in the set position confirmation device 9, when the ring 10 descends from the upper limit position relative to the movable electrode 6 to the lower limit position, in addition to the weight of the ring 10, the air ejection port Since the high air pressure in 15 presses the contact surface of the upper holder 4, the lowering operation of the ring 10 is ensured, and the reliability is further improved.

Further, when the ring 10 is at the lower limit position with respect to the movable electrode 6, the jet air from the air jet port 15 cools the upper holder 4, the taper shank 5, and the movable electrode 6, so that the automation is automated. It is possible to obtain a set position confirmation device more suitable for projection. In addition, although the lower electrode is used as the fixed electrode and the upper electrode is used as the movable electrode in the embodiment, the present invention is not limited to this, and the upper electrode is used as the fixed side and the lower electrode is used as the movable side. The same applies to electrodes. Others The present invention is not limited to the above-described embodiments, and can be implemented in other modes by making appropriate changes.

[0027]

[Effect of device]

 As described above, according to the present invention, when the weld nut is not properly set, a ring whose lower end surface abuts on the weld nut instead of the upper electrode is provided so that it can be moved up and down, and the contact surface having the air ejection port on the upper part of the ring is provided. The welding nut is contacted with the contact surface of the holder to detect the pressure change in the air pressure supply path, and the welding current is cut off and an alarm is issued.Therefore, it seems that the weld nut is welded on the workpiece at an unexpected position or posture. No defective products are produced, reliability is improved and economic loss is suppressed.

In addition, since welding current is not cut off from weld nuts that are not set correctly and will not be welded to the ring, work can continue immediately if the weld nuts are set correctly. The production line down time is significantly shortened, work efficiency is improved, and automated projection can be supported.

Further, since the air injection port provided on the contact surface of the ring moves toward and away from the contact surface of the holder, the air pressure is changed to operate the air converter to cut off the welding current. When the contact surface separates from the contact surface, the separation action is assisted not only by the weight of the ring but also by the air pressure at the air injection port, and the operation is reliable and the reliability is further improved.

[Brief description of drawings]

FIG. 1 is an explanatory sectional view in an axial direction showing an embodiment of the present invention.

FIG. 2 is an operation explanatory diagram when a weld nut is set incorrectly.

FIG. 3 is an axial cross-sectional explanatory view showing an example of conventional measures for preventing defective products.

[Explanation of symbols]

 1 Fixed Side Electrode (Lower Side Electrode) 2 Positioning Pin 3 Weld Nut 4 Upper Holder 4a Abutment Surface 6 Movable Side Electrode (Upper Electrode) 7 Lower Holder 9 Set Position Confirmation Device 10 Ring 10b Contact Surface 11 Support Means (Lower Limit Position Control) 14) Suspension bolt 15 Air jet 17 Pneumatic hose 18 Pneumatic converter 20 Control device 51 Movable electrode 52 Ring W Work

Claims (1)

[Scope of utility model registration request] 1. A weld nut is set on a work having an upper electrode and a lower electrode, which face each other and are capable of relative displacement in the vertical direction, and a weld nut is set on the work, and the weld nut is used as a holder. In a welding device that holds a held upper electrode and welds it by energizing, a ring having an inner diameter capable of vertically moving around the upper electrode and including the weld nut in a normal position; A lower limit position restricting means for restricting the lower limit position of the ring at a point where the end face projects downward from the lower end face of the upper electrode by a dimension slightly smaller than the thickness of the weld nut, and an abutting face of the lower end part of the holder. Provided on the upper contact surface of the ring that contacts and regulates the upper limit position of the ring,
An appropriate number of air jets connected to the air pressure source, an aeroelectric converter provided in the air pressure supply path from the air pressure source, and an alarm and a welding current interruption based on the output of the aeroelectric converter A device for confirming a set position of a projection weld nut, comprising a control means.