DEVICE FOR BLOCKING COOLING WATER OF WELD GUN

Abstract

The present invention relates to a device for blocking cooling water of a weld gun, the device preventing water leakage by blocking the cooling water leaking from the weld gun when a tip provided to the weld gun is replaced. The device for blocking the cooling water of the weld gun comprises: a first piston valve (23) connected to a first solenoid valve (17), operated by a signal of a control unit, so as to start operation according to a signal thereof, and receiving the cooling water from a cooling water inlet end; a main supply pipeline (23) of which one side is connected to a cooling water inlet pipe (27) of the weld gun and the other side is connected to an outlet end of the first piston valve (23); a second piston valve (29) operated by a first solenoid valve (15), and provided on a main discharge pipeline (31) so as to cut off the cooling water discharged or allow the same to pass therethrough; a suction means (35) for suctioning the cooling water filled in the pipeline by means of vacuum and holding the same when the weld gun tip is removed such that the pipeline is opened; and a pressure sensor (49) for sensing that the weld gun tip is separated and the pressure of the pipeline instantly drops so as to drive a circuit, thereby sensing an instant change in fluid pressure; and a cleaning means (47) for removing scales and foreign substances accumulated inside the weld gun, using spraying of air pressure.

Claims

1. A device for blocking cooling water of a weld gun, the device being installed between a cooling water supply pipeline and the weld gun to prevent cooling water left in the weld gun from dropping when a tip of the weld gun is separated, the device comprising: a first piston valve (23) connected to a first solenoid valve (15) operated by a signal of a control unit to be actuated by the signal, the first piston valve (23) being supplied the cooling water from a cooling water inlet end; a main supply pipeline (23), one end of which is connected to a cooling water inlet pipe (27) and an opposite side of which is connected to an output end of the first piston valve (23); a second piston valve (29) operated by the first solenoid valve (15), the second piston valve (29) being installed on a main discharge pipeline (31) to block or pass the discharged cooling water; a suction means (35) for suctioning the cooling water filled on a pipeline through vacuum and holding the cooling water when the tip of the weld gun is removed and the pipeline is opened; and a pressure sensor (49) or a flow sensor configured to detect a pressure on the pipeline from instantly dropping as the tip of the weld gun is separated to drive a circuit, thereby detecting an instant change of the pressure of a fluid.

2. The device of claim 1, wherein the suction means (35) includes: a second solenoid valve (17) operated by a signal of the pressure sensor (49) or the flow sensor; an auxiliary tank (37) installed on the main supply pipeline (23) and the main discharge pipeline (31) to suction the cooling water in the weld gun and hold the cooling water; a third piston valve (39), one side of which is connected to the second solenoid valve (17) and an opposite side of which is connected to the auxiliary tank (37); and a vacuum unit (41) that actuates the auxiliary tank (37) by selectively generating a positive pressure and a vacuum pressure by the third piston valve (39).

3. The device of claim 1, further comprising: a cleaning means (47) for cleaning a cooling line in the interior of a welding gun, wherein the cleaning means (47) includes: a first solenoid valve (15) configured to block introduction and discharge of the cooling water by closing the first piston valve (23) and the second piston valve (29); a third solenoid valve (19) operated by a control unit; a fourth piston valve (43) operated by the third solenoid valve (19), and discharge the cooling water from the welding gun to the outside through the main discharge pipeline (31) by opening only the second piston valve (29); and a fifth piston valve (45) operated by the third solenoid valve (19), and configured to cause air pressure to flow through the welding gun.

Description

DESCRIPTION OF THE INVENTION

[0027] FIG. 1 is a circuit diagram of a device for blocking cooling water of a weld gun according to an embodiment of the present invention, and illustrates a normal operation state.

[0028] FIG. 2 is a circuit diagram of the device for blocking cooling water of the weld gun according to the embodiment of the present invention, and illustrates a state in which supply of cooling water is blocked.

[0029] FIG. 3 is a circuit diagram of the device for blocking cooling water of the weld gun according to the embodiment of the present invention, and illustrates a state in which a tip is fused to be separated from the weld gun or replaced.

[0030] FIG. 4 is a circuit diagram of the device for blocking cooling water of the weld gun according to the embodiment of the present invention, and illustrates an air ejection state for removing foreign substances in the interior of the weld gun.

[0031] FIGS. 5A, 5B, 5C and 5D are schematic cross-sectional views of the device for blocking cooling water of the weld gun according to the embodiment of the present invention.

[0032] FIG. 6 is a diagram illustrating a cooling water supply line of a weld gun according to the related art.

[0033]

TABLE-US-00001 * Description of Main parts of Drawings * 1: device for blocking cooling water of weld gun 3: cooling water pipeline 5: weld gun 7, 9: tip of weld gun 11: cooling water discharge pipeline 13, 19: first and second valves 15, 17, 19: first, second, and third solenoid valves 23, 29, 39, 43, 45: first, second, third, fourth, and fifth piston valves 25: main supply pipeline 27: cooling water inlet pipe 31: main discharge pipeline 33: cooling water ejection pipeline 35: suction means 37: auxiliary tank 41: vacuum unit 47: cleaning means 49: pressure sensor 51: transformer 53: manifold 55: suction pipeline

BEST MODE

[0034] Hereinafter, details of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the direction in which cooling water is supplied is indicated by an arrow of a solid line, and a line in which a pneumatic pressure is supplied is indicated by an arrow of a dotted line.

[0035] A device 1 (hereinafter, simply referred to as ‘a blocking device’) for blocking cooling water of a weld gun according to the present invention is installed between a cooling water supply part 3 and a weld gun 5 to prevent cooling water left in the weld gun 5, a cooling water introduction hose 27, and a cooling water discharge hose 33 from flowing due to the pressure and the self-weight of the water. The cooling water is discharged through a cooling water discharge pipeline 11 after circulating the weld gun 5. The cooling water contained in a tank is supplied by using a hydraulic pump, and the discharged cooling water is recovered to the tank to be used after being cooled.

[0036] The device 1 (hereinafter, referred to as ‘the blocking device’) for blocking cooling water of the weld gun forms a predetermined fluid circuit.

[0037] A pneumatic pressure supply part 13 supplies compressed air to the blocking device 1. The blocking device 1 has three solenoid valves 15, 17, and 19 that are installed in parallel and are operated individually. The compressed air is supplied to a desired part by the solenoid valves to operate the circuit.

[0038] A first piston value 23 is supplied with cooling water from a cooling water inlet end. The first piston valve 23 is connected to a first solenoid valve 15 that is operated by a signal of a control unit to be operated according to the signal. An output end of the first piston valve 23 is connected to the main supply pipeline 25. The main supply pipeline 25 is connected to a cooling water inlet pipe 27 of the weld gun. A second piston valve 29 operated by the first solenoid valve 15 is installed on the main discharge pipeline 31 to block or pass the discharged cooling water. The main discharge pipeline 31 is connected to a cooling water ejection pipeline 33 of the weld gun.

[0039] As the first solenoid valve 15 is switched on or off, pistons 231 and 291 of the first and second piston valves are operated upwards and downward in the drawings to block introduction and discharge of the cooling water. FIGS. 1 and 5A illustrate a normal operation state in which the cooling water is supplied and discharged, and FIGS. 2 and 5B illustrate a state in which the supply and discharge of the cooling water are blocked.

[0040] Meanwhile, according to the present invention, a suction means 35 for suctioning the cooling water filled on the pipeline through vacuum and containing the cooling water when the weld gun tips 7 and 9 are removed and the pipeline is opened.

[0041] The suction means 35 is operated by the second solenoid valve 17. The suction means includes a third piston valve 39, one side of which is connected to the second solenoid valve 17 and an opposite side of which is connected to the auxiliary tank 37, and a vacuum unit 41 for generating a vacuum pressure. Further, in order to suction and contain the cooling water in the weld gun, an auxiliary tank 37 installed on the main supply pipeline 25 and the main discharge pipeline 31 is further provided. Since the auxiliary tank 37 prevents the cooling water, which is to drop, from dropping by using the vacuum pressure, it does not require a large capacity. FIGS. 3 and 5C illustrate a state in which the cooling water has been suctioned into the auxiliary tank 37 while the weld gun is opened.

[0042] Meanwhile, the third solenoid valve 19 is connected to a fourth piston valve 43 and a fifth piston valve 45 to operate the pistons 431 and 451 installed in the piston valves. The third solenoid valve 19, the fourth piston valve 43, and the fifth piston valve 45 correspond to a cleaning means 47 for cleaning the blocking device 1 and the cooling line in the interior of the weld gun.

[0043] A pressure sensor 49 is installed on the main discharge pipeline 11 of the blocking device to detect a drop of an instant pressure on the pipeline as the weld gun tips 7 and 9 are separated so as to drive the circuit. The pressure sensor 49 is adapted to detect a change in the instant pressure of the supplied fluid and may be replaced by a flow sensor or the like. FIGS. 4 and 5D illustrate a state in which cleaning is performed while air is supplied and discharged to and from the pipeline.

[0044] Reference numeral 51′ denotes a transformer, and reference numeral 53 denotes a manifold to which the blocking device 1 and the weld gun are jointed.

[0045] Hereinafter, an operation of the above-described configuration will be described.

[0046] First, a normal state will be described with reference to FIGS. 1 and 5A. The normal state refers to a state in which the weld gun performs an operation, and refers to a state in which the cooling water is supplied and discharge to and from the weld gun 5.

[0047] In this state, all the first, second, and third solenoid valves 15, 17, and 19 are switched off. Distal ends 151 and 152 of the pipelines connected to the first solenoid valve 15 pushes the pistons 231 and 291 to allow the cooling water to flow along the direction of an arrow indicated by a solid line. Since the pressure of the compressed air supplied by the first, second, and third solenoid valves 15, 17, and 19 is higher than the cooling water supply pressure, the pistons are operated as illustrated in the drawings to allow the cooling water to flows as illustrated.

[0048] In this state, the compressed air ejected from the distal ends 171 and 172 of the pipeline connected to the second solenoid valve 17 pushes the pistons 391 and 371 such that the pistons are biased to the right side in the drawings.

[0049] The cooling water supply unit 3 supplies the cooling water to the weld gun 5 through the first piston valve 23, the second piston valve 29, and the main supply pipeline 25. The cooling water that passed through the weld gun 5 is discharged to the cooling water discharge pipeline 11 though the main discharge pipeline 33.

[0050] FIGS. 2 and 5B correspond to a state in which both the supply and discharge of the cooling water are blocked by switching on only the first solenoid valve 15. Accordingly, both the first and second piston valves 23 and 29 are operated to prevent the cooling water from being introduced or discharged. This state refers to a state in which the welding operation of the weld gun is not performed, and represents a state in which the supply of the cooling water is not necessary.

[0051] FIGS. 3 and 5C illustrate a state in which the tips 7 and 9 of the weld gun are replaced due to wear or are fused to the product to be accidently separated from the weld gun 5.

[0052] In this state, the pressure of the cooling water of the cooling water pipeline decreases instantly. According to the embodiment of the present invention, in particular, the pressure sensor 49 is installed on the main discharge pipeline 31, and the pressure sensor 49 detects an instant drop of the pressure in the cooling water pipeline to allow the control unit to operate the device.

[0053] In this state, the first and second solenoid valves 15 and 17 remains switched on, and the third solenoid valve 19 remains switched off. In this case, the compressed air is supplied to several sites as indicated by an arrow.

[0054] First, as the first solenoid valve 15 is switched on, the compressed air is supplied to the distal ends 153, 154, and 155 of the pipeline, and as the piston 231 of the first piston valve is actuated upwards, the cooling water is prevented from passing through the first piston valve 23. Further, at the same time, the compressed air actuates the piston 291 of the second piston valve 29 downwards as illustrated after locating the piston 431 to the illustrated location through the distal end 154 connected to the fourth piston valve 43 and the distal end 155 of the second piston valve. Accordingly, the cooling water contained in the cooling water ejection pipeline 33 also is blocked by the second piston valve 29 and is prevented from being discharged. As a result, the cooling water is confined in the device 1 for blocking the cooling water of the weld gun and is prevented from being introduced or discharged.

[0055] In this situation, the suction unit 35 is actuated to suction the cooling water filled in the weld gun by the vacuum pressure to hold the cooling water so that the cooling water does not drop to the outside of the weld gun.

[0056] The suction means 35 includes a second solenoid valve 17, a third piston valve 39 that controls a supply path of the compressed air with the second solenoid valve 17, a vacuum unit 41 connected to the third piston valve, and an auxiliary tank 37 for holding the suctioned cooling water of a predetermined amount.

[0057] The second solenoid valve 17 pushes the piston 391 of the third piston valve 39 leftwards in the drawings to form vacuum. The vacuum unit discharges the compressed air (M) to form a negative pressure in a venturi tube 174, and the negative pressure is operated through the suction pipeline 55 to move the piston 371 of the auxiliary tank leftwards in the drawings. In this process, the cooling water contained in the main supply pipeline 25, the weld gun 5, and the main discharge pipeline 31 is suctioned into and filled in the auxiliary tank 37.

[0058] Hereinafter, the cleaning means 47 will be described with reference to FIGS. 4 and 5D.

[0059] The present invention includes a system for periodically cleaning the device 1 for blocking cooling water of the weld gun. The cleaning means 47 includes a third solenoid valve 19, fourth and fifth piston valves 43 and 45 that control the supply path of the compressed air with the third solenoid valve 19.

[0060] The cleaning means 47 is actuated by switching on the first and third solenoid valves 15 and 19 and switching off the second solenoid valve 17. The compressed air supplied to the distal end 192 extending from the fifth piston valve 45 by the third solenoid valve 19 supplies the air to the pipelines 25, 27, 33, and 31 after pushing the piston 451 of the fifth piston valve downwards. Further, the compressed air introduced to the distal end 193 extending from the fourth piston valve 43 operates the piston 431 of the fourth piston valve 43 upwards in the drawings, and allows the compressed air introduced into the second piston valve 29 to actuate the piston 291 of the second piston valve upwards in the drawings through the distal end 154 of the pipeline to open the second piston valve by using the first solenoid valve 23. Accordingly, the air can be discharged to the outside through the cooling water discharge pipeline 11.

[0061] In this state, the first solenoid valve 15 lifts the piston 231 of the first piston valve to prevent introduction of the cooling water. Further, the second solenoid valve 17 discharges the compressed air along the main supply pipeline 25, the weld gun 5, the main discharge pipeline 33, and the cooling water discharge pipeline 11 via the third piston valve 41 in an off state.

INDUSTRIAL APPLICABILITY

[0062] Since an on/off valve and a check valve applied to an existing robot welding line is not necessary and cooling water is hardly leaked according to the present invention, the cooling water is hardly discharged when a tip is replaced by a mechanical device or by an operator. Since the device for blocking cooling water of a weld gun according to the present invention can be installed to be spaced apart from the weld gun by about 15 m, it can be easily maintained and managed.

[0063] The configurations illustrated and described above is merely a preferred embodiment based on the technical spirit of the present invention. It is noted that an ordinary person in the art to which the present invention can make various modifications based on the common technical sense but the modifications also fall within the scope of the present invention.