JP3179705U - Air blow mechanism for bolt welding - Google Patents

Abstract

An air blow mechanism for bolt welding that has a simple configuration and that can prevent unnecessary air from being blown by blowing air only at the time of welding.
In a lower electrode unit (1) of a bolt welder, a holder tube (3) is connected to a lower part of a lower electrode (2), a connecting member (4) provided with an air supply unit (10) is connected to the lower part of the lower electrode unit, and A compression spring 7 and a guide pin 8 are housed inside the bag hole 4h. Normally, the tapered portion 8t of the guide pin 8 urged upward by the compression spring 7 is in close contact with the tapered valve seat to block the compressed air in the bag hole 4h from entering the cylinder of the holder cylinder 3. When the guide pin 8 is pushed down from below, the tapered portion 8t and the tapered valve seat are separated from each other so that the compressed air in the bag hole 4h enters the cylinder of the holder cylinder 3.
[Selection] Figure 1

Description

  The present invention provides an air blow mechanism for removing foreign matter between a bolt and a steel plate during welding in a welding machine that welds a weld bolt to a steel plate or the like by energizing the workpiece while pressing the workpiece between a pair of upper and lower electrodes. About.

Conventionally, in a welding machine that welds a weld bolt to a steel plate by energizing a workpiece while pressing a workpiece between a pair of upper and lower electrodes, a parts feeder is a technology that removes foreign matter such as sputtering and other fine dust during welding. A technology is known in which compressed air is blown into the gap between the guide pin and the guide pin insertion hole of the lower electrode using an air circuit for advancing the push rod of the separator device for separating the weld bolt fed from ing. (For example, refer to Patent Document 1.)
Also, when welding the stud bolt to the workpiece, when the stud bolt gripped by the robot arm approaches the welding position and reaches a predetermined position, air is blown toward the workpiece surface for a certain period of time to wipe off the oil film on the workpiece surface. Such techniques are also known. (For example, see Patent Document 2.)

Japanese Patent Application Laid-Open No. 10-328851. Japanese Utility Model Publication No. 62-193968.

By the way, in the case of the technique of the above-mentioned patent document 1, when the first electromagnetic valve of the bolt setting cylinder is operated and the guide pin is lowered to a predetermined position, the detector detects the set state, and the electromagnetic valve is set by a set confirmation signal. When the spindle reaches the return position, the second electromagnetic valve of the air cylinder of the separator device is actuated to drop the welding bolt to the feed port, and then the timer is started to activate the third electromagnetic valve for air blow. The valve is operated to eject the air, but a special control circuit is provided and used as an air blow mechanism for ejecting the air, which causes a problem that the device configuration becomes complicated.
The technique of Patent Document 2 also has a problem that the apparatus becomes complicated because it is necessary to provide a control circuit for blowing air onto the work surface and a circuit for blowing air for a certain period of time.

  Therefore, the present invention has a simple configuration without causing complication of the apparatus, and an object of the present invention is to eliminate unnecessary air blowing by enabling air to be blown only during welding.

  In order to achieve the above object, the present invention provides an air blow mechanism on a lower electrode side of a bolt welder used when welding a weld bolt, wherein the upper electrode is biased upward by a compression spring on the lower electrode side. A guide pin is provided that descends and presses the head of the bolt downward and is pushed down by a predetermined stroke, and when this guide pin moves downward, a tapered portion formed on the guide pin and a surrounding tapered valve seat Is released, the air passage for sending the compressed air from the lower air supply part into the bolt insertion hole of the lower electrode on the upper side is opened, and the guide pin moves upward by the urging force of the compression spring. The tapered portion of the guide pin and the surrounding tapered valve seat are in close contact with each other to block the air passage.

The air sent into the bolt insertion hole of the lower electrode blows out to the upper surface of the workpiece through the hole of the workpiece such as a steel plate, and wipes off fine dust between the bolt head and the workpiece and foreign matters such as sputtering during welding. To do.
In this way, a guide pin is provided with a taper that is urged by a compression spring and is detachable from the surrounding valve seat, and is compressed only when the upper electrode descends and the bolt head is pressed downward to energize. If the upper electrode rises after jetting air and welding, the guide pin rises to block the air passage, and the apparatus can be configured simply without causing unnecessary air flow.

Further, in the present invention, the air feeding unit constantly feeds compressed air.
In this way, even if compressed air is constantly supplied, the ejection of air can be controlled by the contact and separation of the tapered portion of the guide pin and the surrounding valve seat. Can be configured.

  When welding weld bolts, an air blow mechanism is used to remove fine dust between the bolt head and workpieces such as steel plates and foreign matter such as sputtering, and is biased by a biasing spring and separated from the surrounding tapered valve seat. Provided with a freely accessible guide pin, the guide pin is lowered with the lowering of the upper electrode, and when the upper electrode is lifted after the completion of welding, the blowout of air is stopped, thereby simplifying the apparatus. Useless air is suppressed. In addition, if the compressed air is constantly supplied in the air supply unit, the apparatus can be further simplified.

It is explanatory drawing of the state which set the workpiece | work and the volt | bolt in the lower electrode unit provided with the air blow mechanism which concerns on this invention. It is a top view of a lower electrode unit. It is a perspective view of a lower electrode unit. It is a disassembled perspective view of a lower electrode unit. It is explanatory drawing which shows the separation / contact state of the taper part of a guide pin, and the surrounding taper-shaped valve seat, (a) is a close state, (b) is a detachment | leave state. It is explanatory drawing of the welding method of a weld bolt, (a) is a bolt set state, (b) is the state which pressed the volt | bolt with the upper electrode, (c) is the state which supplied the electricity and melt | dissolved the weld part.

  The air blow mechanism for bolt welding according to the present invention has a simple structure when welding a weld bolt to a workpiece such as a steel plate, but it blows useless air by blowing air around the weld only when welding. First, a joining method for welding the weld bolt B to a workpiece W such as a steel plate will be described with reference to FIG.

  The weld bolt B has weld portions u at a plurality of positions on the lower surface of the bolt head, and is formed on a workpiece W such as a steel plate placed on the lower electrode 2 as shown in FIG. After the bolt shaft of the bolt B is inserted into the hole h and set so as to leave a predetermined gap between the upper surface of the workpiece W and the weld portion u, the bolt head is moved downward by the upper electrode 16 as shown in FIG. The bolt B and the workpiece W are sandwiched between the upper electrode 16 and the lower electrode 2 and pressed, and the weld portion u is melted and joined by energizing between the upper electrode 16 and the lower electrode 12. Is the method.

At this time, if there is foreign matter such as fine dust or oil or sputtering at the time of welding between the workpiece W upper surface and the bolt head lower surface around the welded portion, the bonding strength decreases or the welding quality decreases. It is preferable to remove these foreign matters during welding.
Therefore, the air blow mechanism of the present invention is a device configuration suitable for preventing such problems.

  As shown in FIGS. 1 to 4, the lower electrode unit 1 according to the present invention includes a lower electrode 2 having a bolt insertion hole 2 h through which a bolt shaft can be inserted, and a holder connected below the lower electrode 2. A cylinder 3, a connecting member 4 connected to the lower side of the holder cylinder 3, and a cooling mechanism 5 for cooling the lower electrode 2, the lower electrode 2, the holder cylinder 3 and the connecting member 4 are The holder cylinder 3 can be integrated by screwing with screw parts provided at the upper part and the lower part of the holder cylinder 3, and the cooling mechanism 5 can be fitted to the upper outer peripheral part of the holder cylinder 3 and screwed. Has been.

  Further, an insulating sleeve 6 (FIG. 1) is embedded in the upper part of the holder cylinder 3 in the cylinder, and when the bolt shaft is inserted into the cylinder of the holder cylinder 3, between the bolt B and the holder cylinder 3. Electrical insulation can be achieved.

  A stepped bag hole 4h is formed at the bottom of the central portion of the connecting member 4, and a compression spring 7 is housed in the deepest part of the central portion of the bag hole 4h. The upper portion of the placed guide pin 8 extends to the inside of the holder tube 3.

  A tapered portion 8t whose diameter decreases upward is formed on the outer peripheral portion on the lower side of the guide pin 8, and the tapered portion 8t is a tapered valve seat 3t formed in the cylinder of the holder tube 3. (FIG. 5) is detachable. When the guide pin 8 is urged upward by the compression spring 7, the tapered portion 8t of the guide pin 8 is brought into close contact with the tapered valve seat 3t of the holder cylinder 3, as shown in FIG. As shown in FIG. 5B, when the guide pin 8 is pushed down from above and lowered downward, the taper portion 8t and the bag hole 3h of the connecting member and the passage in the cylinder of the holder cylinder 3 are blocked. The tapered valve seat 3t is separated so that the bag hole 3h of the connecting member and the passage in the cylinder of the holder cylinder 3 are opened.

Further, an air supply unit 10 for supplying compressed air into the bag hole 3h is provided on one side portion of the connecting member 4 so that the compressed air can be supplied constantly.
Further, a lower portion of the connecting member 4 is provided with a shank portion 4s for connecting to the welding device.

  The cooling mechanism 5 includes a cooling ring 11 that can be fitted to the outer peripheral portion of the holder tube 3 also in the vicinity of the lower electrode 2, and a screwing portion 12 for fixing the cooling ring 11 to the outer peripheral portion of the holder tube 3 (FIG. 1). ), A water supply portion 14 for supplying cooling water into the cooling passage 13 in the cooling ring 11, and a drainage portion 15 for draining the cooling water in the cooling passage 13, and the cooling passage 13 of the cooling ring 11. The cooling water is circulated to cool the heat generated around the lower electrode 2.

  The lower electrode unit 1 as described above is connected to a welding apparatus, and the workpiece W is positioned on the lower electrode 2. At this time, positioning is performed so that the hole h of the workpiece W is coaxial with the bolt insertion hole 2 h of the lower electrode 2.

  Next, the bolt shaft of the weld bolt B is inserted through the hole h of the steel plate W. Then, the position of the guide pin 8 at this time is moved to the uppermost position by the compression spring 7, and the connecting member is in a position where the tapered portion 8 t of the guide pin 8 is in close contact with the tapered valve seat 3 t of the holder cylinder 3. 4 and the communication path in the cylinder of the holder cylinder 3 are cut off, and between the weld part u of the head of the bolt B abutting on the upper surface of the guide pin 8 and the upper surface of the work W. A predetermined gap is generated. (Fig. 6 (a))

When the setting of the bolt B is completed in this way, the upper electrode 16 starts to descend, presses the bolt head, and pushes the bolt B downward. (Fig. 6 (b))
Then, the guide pin 8 starts to descend due to the descending of the bolt B, the tapered portion 8t and the tapered valve seat 3t are separated from each other, and the compressed air supplied into the bag hole 4h flows into the cylinder of the holder cylinder 3. The compressed air is blown out toward the upper surface of the workpiece W through the bolt insertion hole 2h of the lower electrode 2 and the hole h of the workpiece W. For this reason, the foreign material on the upper surface of the workpiece W is wiped off.

When the pressurization by the upper electrode 16 is completed, a current is passed through the upper electrode 16 and the lower electrode 2 to perform welding. (Fig. 6 (c))
And when welding is completed, the upper electrode 16 will raise. Then, the guide pin 8 and the bolt B are lifted by the action of the compression spring 7, the taper portion 8t of the guide pin 8 is brought into close contact with the tapered valve seat 3t, and the compressed air from the bag hole 4h into the cylinder of the holder cylinder 3 is obtained. Inflow stops and air blow to the upper surface of the workpiece W also stops.
That is, air blow is performed only when welding, and air blow is stopped at times other than during welding, so that air is not blown out unnecessarily.

  Moreover, since the apparatus configuration is simple, it can be configured at low cost without using an expensive electromagnetic valve or the like.

In addition, this invention is not limited to the above embodiments. Those having substantially the same configuration as those described in the claims of the utility model registration of the present invention and having the same operational effects belong to the technical scope of the present invention.
For example, the tapered valve seat 3t is not necessarily provided in the holder cylinder 3, but may be provided in the connecting member 4 or the like.

  As an air blow mechanism for bolt welding, since it can be constructed at low cost and can prevent unnecessary air blowing, it is expected to be widely used in the future.

  DESCRIPTION OF SYMBOLS 1 ... Lower electrode unit, 2 ... Lower electrode, 3 ... Holder cylinder, 3t ... Tapered valve seat, 4 ... Connection member, 5 ... Cooling mechanism, 7 ... Compression spring, 8 ... Guide pin, 8t ... Tapered part, 16 ... Upper electrode, B ... weld bolt, W ... workpiece.

Claims (2)

An air blow mechanism on a lower electrode side of a bolt welder used when welding a weld bolt, wherein the lower electrode side is urged upward by a compression spring and the upper electrode is lowered to lower the head of the bolt. A guide pin that is pushed downward and drops by a predetermined stroke when pressed downward is provided. When this guide pin moves downward, the tapered portion formed in the guide pin and the surrounding tapered valve seat are separated, and the lower air Opening the air passage for sending compressed air from the feeding part into the bolt insertion hole of the lower electrode on the upper side, and moving the guide pin upward by the urging force of the compression spring, the taper part of the guide pin and the surrounding area An air blow mechanism for bolt welding characterized in that the air passage is blocked by being in close contact with the tapered valve seat. The air blow mechanism for bolt welding according to claim 1, wherein the air feeding unit constantly feeds compressed air.

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