JPH07232283A - Electrode tip cooling device for spot welding machine - Google Patents

Abstract

PURPOSE:To improve the cooling efficiency and also to realize the environmental arrangement and a water saving effect by cooling an electrode tip of a spot welding machine with the use of mixed gas of compressed air and water. CONSTITUTION:When compressed air and water are supplied into a cooling supplying path a, the compressed air and the water are mixed at its branching point, they are formed into the mist like mixture of high pressure, small fluid resistant gas and supplied inside the electrode, and it circulates in a rapid flow rate and cools the inside of the electrode. The cooling effect can be more improved corresponding to the temperature rising condition by operating the action of an opening and closing valves 9, 10 during welding or operating at the fixed time. Further, by using the mixture of the water and the compressed air replacing the water, the pressure regulation is easily performed and the flow rate is also increased because the fluid resistance is small.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for cooling an electrode tip of a spot welding machine by using a mixed gas of compressed air and water.

[0002]

2. Description of the Related Art Generally, as shown in FIG. 4, in an electrode device of a spot welding machine, a cooling pipe 3 is inserted into an electrode holder 17 of an electrode device 1 on the same axis, and a tip insertion hole at the tip of the holder is tapered. The electrode tip 18 is inserted. Then, the IN and OUT hose openings 19 and 20 are connected as shown by arrows to form a water circulation path for cooling water inside the electrode.

As described above, conventionally, water is used for cooling the electrode tip by water cooling, and water is passed through the water pipe. The area around the electrode tip of the spot welder has a narrow pipe cross-section due to its structure, while the water pressure is supplied at tap water pressure or a low pressure close to this. Therefore, there is a limit to the amount of water and the flow velocity,
The amount of cooling heat per unit time is limited, and when more cooling is required, the electrode tip must be made thicker, and naturally the holder to which it is attached must be made larger.

[0004]

The conventional cooling of the electrode tip by water cooling has the following problems. (1) The tip of the electrode tip wears and deforms, so it must be changed from time to time, but at that time it spouts and adversely affects the surrounding environment. (2) The cooling effect of the electrode tip is not always ideal. (3) If only water is used, the amount of cooling water increases.

[0005]

The present invention takes the following technical means in order to solve the above problems.

That is, a feature is that a mixed gas of compressed air and water is used for cooling the electrode tip of the spot welding machine.

In the above electrode tip cooling device, the supply of compressed air or the supply of water, or both of them,
An on-off valve is provided in the cooling supply path so that the supply can be performed during the welding operation or for a predetermined fixed time.

In the electrode tip cooling device, the compressed air to be supplied is exhausted from an electrode pressurizing cylinder.

[0009]

[Action]

It is easy to increase the pressure of the mixed gas of compressed air and water, and since the fluid resistance is small, the flow velocity is high. In addition, the small amount of water forms a part of steam, and the heat of vaporization helps to cool the electrode tip, and this steam does not interfere with the flow of new mixed gas immediately.

Since it is a mixed gas of compressed air and water that is more effective than cooling by water, it suffices to flow it through the electrode tip cooling pipe before and after energization for welding, and there is no flow when exchanging electrode tips. Or, there is no residual water, so there is no adverse effect of water on the surrounding environment. As a matter of course, the operator is not inflicted when exchanging the electrode tip.

The water for cooling is saved.

[0013]

1 is a piping diagram of an electrode tip cooling system showing a first embodiment of the device of the present invention.

An on-off valve is provided so that compressed air or water can be supplied, or both of them can be supplied during the welding operation or for a predetermined fixed time.

Reference numeral 1 is an electrode device. Reference numeral 2 is an electrode pressurizing cylinder for driving the electrode device. Reference numeral 3 is a water-cooled pipe, which is internally provided on the same axis as the electrode device, and forms an IN / OUT water flow path inside the electrode as indicated by the arrow. The cooling supply path a on the IN side of the electrode is an air pipe c connected to the air supply source 5.
And a water cooling pipe b connected to the cooling water supply source 6, and a variable throttle valve 7 and a variable throttle valve 8 are attached to the secondary side of each branched water cooling pipe b and air pipe c. An open / close valve 9 and an open / close valve 10 are provided.

The drainage flowing out from the drainage path d on the OUT side of the electrode flows into the drainage container 11.

In the above structure, when the compressed air and water are supplied to the cooling supply path a, the compressed air and water are mixed at the branch point to form a mist-like mixed gas having a high pressure and a small fluid resistance. Is supplied into the electrode and circulates inside the electrode at a high flow rate to cool it. If the opening / closing valve 9 and the opening / closing valve 10 are operated during the welding operation or at a predetermined time, the cooling effect can be further enhanced according to the temperature rising condition of the electrode.

Next, FIG. 2 is a piping diagram of an electrode tip cooling system showing a second embodiment of the device of the present invention.

In this case, the compressed air supplied to the cooling supply path a uses the exhaust of the electrode pressurizing cylinder.

The air supply / exhaust path e and the air supply / exhaust path f of the electrode pressurizing cylinder 2 are mediated by one opening / closing valve 12 connected to the air supply source 5, and are the cooling supply path on the IN side of the electrode. connected to a.

A water cooling pipe b from a cooling water supply source 6 via a variable throttle valve 13 and a check valve 14 is branched and connected to the cooling supply path a.

A variable throttle valve 15 that throttles the air supply port or a variable throttle valve 16 that throttles the air exhaust port is provided in the cooling supply path a. This is because the operation of the electrode pressurizing cylinder is decided with priority, so that it can be adjusted by the throttle valve 15 and the throttle valve 16.

The drainage from the drainage path d on the OUT side of the electrode flows into the drainage container 11 provided at the outlet.

As can be seen from the enlarged view of FIG. 1, the branch point of the water cooling pipe b and the air pipe c has a structure for generating a mist-like mixed gas. The diameter of the tube is small and the air tube c is thick.

FIG. 3 is a graph comparing the effect of cooling the electrode in the case of using the mixed gas of the device of the present invention with the case of using the conventional cooling water.

The experimental method was as follows: using an electrode with a thermoelectric element inserted, continuous one-point / one-second spotting was performed, the temperature was raised to about 70 ° C., the current flow was stopped, the electrode was opened, and the electrode temperature was changed. The down curve was measured.

As a result, as can be seen from the graph, the cooling down curve of the mixed gas has a sharply shorter time than the conventional cooling down curve of only running water, and it is understood that the electrode cooling effect is high.

[0028]

As described above, according to the device of the present invention, the pressure of the cooling mixed gas can be easily adjusted by using the mixed gas of compressed air and water instead of the conventional water as the cooling medium. Moreover, since the fluid resistance is small, the flow velocity is also high. In addition, the small amount of water forms a part of steam, and the heat of vaporization helps to cool the electrode tip, and this steam does not interfere with the flow of new mixed gas immediately.

Since it is a mixed gas of compressed air and water that is more effective than cooling by conventional cooling water, it suffices to flow it to the electrode tip cooling pipe before and after energization for welding, and it will flow when replacing the electrode tip. Not only is there no residual water, there is no adverse effect of water on the surrounding environment. Further, the operator can naturally be relieved of the pain at the time of exchanging the electrode tip. The resource saving effect of saving the cooling water is also great.

[Brief description of drawings]

FIG. 1 is a piping diagram of an electrode tip cooling system showing a first embodiment of the device of the present invention.

FIG. 2 is an electrode tip cooling system piping diagram showing a second embodiment of the device of the present invention.

FIG. 3 is a graph comparing the electrode cooling effect in the case of using the mixed gas of the device of the present invention with that in the case of using the conventional cooling water.

FIG. 4 is a cross-sectional view showing a water circulation path of a conventional general electrode device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Electrode device 7 Variable throttle valve 2 Electrode pressurizing cylinder 8 Variable throttle valve 3 Water cooling pipe 9 Open / close valve 5 Air supply source 10 Open / close valve 6 Cooling water supply source 11 Drainage container 12 Open / close valve 17 Electrode holder 13 Variable throttle valve 18 Electrode tip 14 Check Valve 15 Variable Throttle Valve 16 Variable Throttle Valve a Cooling Supply Path b Water Cooling Pipe c Air Pipe d Drainage Path e Air Supply / Exhaust Path f Air Supply / Exhaust Path

Claims (3)

[Claims] 1. An electrode tip cooling device for a spot welder, which uses a mixed gas of compressed air and water to cool the electrode tip of the spot welder. 2. The electrode tip cooling device according to claim 1, wherein a compressed air supply or a water supply, or both of them, is opened / closed in a cooling supply path so as to be supplied during a welding operation or for a predetermined fixed time. Electrode tip cooling device for spot welders equipped with a valve. 3. The electrode tip cooling device for a spot welding machine according to claim 1, wherein compressed air to be supplied is exhausted from an electrode pressurizing cylinder.