ELECTRODE DEVICE

Abstract

An electrode device for water-cooling type resistance welding that constantly circulates cooling water efficiently to the proximity of an electrode tip, allowing the electrode to stably cool down. A cooling pipe 11 is inserted inside a device body 1 from a lower side thereof, and cooling water ejected from a tip opening 11a of the cooling pipe 11 cools a cap tip 10 placed on the tip of a shank 8. The cooling pipe 11 is movable in the axial direction of the device body 1 and fixable at any position. As a result, even with a change in the length of the shank 8, the tip opening 11a of the cooling pipe 11 can always be positioned in the proximity of the cap tip 10, allowing the cap tip 10 to cool down reliably and the form of the electrode tip to be maintained stably for a long time.

Claims

1. An electrode device comprising: a device body that includes an electrode and a straight holder connected with each other in a straight line, the electrode including a cap tip placed on a tip of a shank having a cylindrical shape, the straight holder having a cylindrical shape; and a cooling pipe that is inserted inside the device body from a lower side of the device body and has a tip opening located proximate to the cap tip; wherein cooling water ejected from the tip opening of the cooling pipe cools the cap tip, flows through a gap between an outer peripheral surface of the cooling pipe and inner peripheral surfaces of the shank and the straight holder, and then is discharged outside from a lower part of the straight holder, and the cooling pipe is installed so as to be movable in an axial direction of the device body and fixable at any position.

2. The electrode device according to claim 1, wherein a cooling pipe support member provided with a supply port for the cooling water is positioned at a lower part of the device body, and the cooling pipe support member supports a base end of the cooling pipe.

3. The electrode device according to claim 2, wherein the cooling pipe support member comprises: a base provided with a supply port for the cooling water; and a cylindrical body erected on the base, the cylindrical body is inserted in the straight holder so as to be movable in an axial direction, and the cooling pipe support member is movable in the axial direction of the straight holder and fixable at any position by engaging a long groove portion provided on an outer peripheral wall of the cylindrical body with a locking bolt screwed on a side face of the straight holder.

4. The electrode device according to claim 2, wherein the cooling pipe support member comprises: a base provided with a supply port for the cooling water; and a fixing member that is fixed to a lower part of the straight holder separately from the base and that penetrates and supports the cooling pipe, wherein the fixing member is provided with a discharge port for the cooling water, and the cooling pipe support member is movable in an axial direction of the straight holder and fixable at any position by providing a lock mechanism at a lower portion of the fixing member, the lock mechanism having a ring-type steel pipe joint structure that uses an compression ring to fix the cooling pipe at any position.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] FIG. 1 is a sectional view of an embodiment according to the present invention.

[0018] FIG. 2 is a sectional view of the embodiment in which a shank with a different length from that in FIG. 1 is attached.

[0019] FIG. 3 is a sectional view of another embodiment.

[0020] FIG. 4 is a sectional view of the embodiment in which a shank with a different length from that in FIG. 3 is attached.

[0021] FIG. 5 is an enlarged sectional view of a lock mechanism.

[0022] FIG. 6 is a sectional view of a related art example.

DETAILED DESCRIPTION OF THE INVENTION

[0023] In the following, preferred embodiments of the present invention are described with reference to the drawings.

[0024] FIG. 1 is a sectional view of an electrode device for spot welding according to a first embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a device body that includes an electrode 7 and the straight holder 3 connected with each other in a straight line, the electrode 7 including a cap tip 10 placed on the tip of a shank 8 having a cylindrical shape, the straight holder 3 having a cylindrical shape. The shank 8 and the cap tip 10 may be molded in one piece. A cooling pipe 11 is inserted inside the device body 1 from the lower side of the device body 1 and a tip opening 11a of the cooling pipe 11 is positioned proximate to the back side of the cap tip 10.

[0025] Cooling water ejected from the tip opening 11a of the cooling pipe 11 cools the cap tip 10, flows through the gap between the outer peripheral surface of the cooling pipe 11 and the inner peripheral surface of the shank 8 and the gap between the outer peripheral surface of the cooling pipe 11 and the inner peripheral surface of the straight holder 3, and then is discharged outside from a lower part of the straight holder 3.

[0026] A cooling pipe support member 2 provided with a supply port 2b for the cooling water is positioned at a lower part of the device body 1, and the cooling pipe support member 2 supports a base end of the cooling pipe 11. By moving the position of the cooling pipe support member 2 with respect to the axial direction of the device body 1, the tip opening 11a of the cooling pipe 11 is adjusted to be positioned in the proximity of the inner surface of the electrode, thereby cooling the cap tip 10 efficiently.

[0027] The cooling pipe support member 2 also serves as a lid to seal the lower end of the straight holder 3.

[0028] The cooling pipe support member 2 has a supply port 2b for the cooling water formed on the side of the base 2a at the base end, a communicating tube 2c is formed to connect the tip opening with a supply port 2b for the cooling water, and a long groove 2d is formed on the outer surface of the communicating tube 2c in the axial direction. A cylindrical body 2e is erected on top of the base 2a.

[0029] Large diameter portions 3b, 3c are formed at ends of a through hole 3a of the straight holder 3, and a discharge port 3d for the cooling water is formed on the side proximate to the large diameter portion 3c at the base end. A locking bolt 4 is screwed on the side of the large diameter portion 3c at the position corresponding to the long groove 2d, and by tightening the locking bolt 4 and pressing the tip against the bottom face of the long groove 2d, the straight holder 3 is fixed to the cooling pipe support member 2.

[0030] In FIG. 1, reference numerals 5 and 6 denote connectors for connecting cooling water hoses (not illustrated) to the supply port 2b and discharge port 3d.

[0031] In FIG. 1, reference numeral 7 denotes an electrode. The electrode 7 includes a shank 8 having a cylindrical shape and a cap tip 10 mounted on the tip of the shank 8. FIG. 2 illustrates a shank 9 that is a longer type than the shank 8. The shank 8 or 9 is mounted by press-fitting the base end into the large diameter portion 3b at the tip of the through hole 3a in the straight holder 3, and the cap tip 10 is mounted on the shank 8 or 9 by press-fitting the tip of the shank 8 or 9 into a mounting hole 10a, which is open at the base end.

[0032] Reference numeral 11 denotes a cooling pipe with the tip cut off at an angle. The cooling pipe 11 is mounted by press-fitting the base end into the communicating tube 2c of the cooling pipe support member 2, passes through the through hole 3a of the straight holder 3, and a through-hole 8a of the shank 8 or a through-hole 9a of the shank 9, and is positioned so that the tip opening 11a is in the mounting hole 10a of the cap tip 10 and in the vicinity of the cap tip 10.

[0033] As described above, the cooling pipe support member 2 illustrated in FIG. 1 includes: the base 2a provided with the supply port 2b for the cooling water on the side face; and the cylindrical body 2e erected on the base, in which the cylindrical body 2e is inserted in the straight holder 3 so as to be movable in the axial direction, and the cooling pipe support member 2 is movable in the axial direction of the straight holder 3 and fixable at any position by engaging the long groove 2d provided on the outer peripheral wall of the cylindrical body 2e with the locking bolt 4 screwed on the side face of the straight holder 3.

[0034] The following describes a method for cooling the cap tip 10 with the electrode device.

[0035] The cooling water is supplied through the supply port 2b of the cooling pipe support member 2, flows through the cooling pipe 11, and then is ejected from the tip toward inside the cap tip 10 to cool the cap tip 10. The cooling water then passes through the gap between the outer peripheral surface of the cooling pipe 11 and the inner peripheral surface of the shank 8 or 9, then through the gap between the outer peripheral surface of the cooling pipe 11 and the inner peripheral surface of the straight holder 3, and is discharged outside through the discharge port 3d. The cooling water is circulated in the same manner to cool the cap tip 10, and this maintains the form of the cap tip 10 stably for a long time, preventing the occurrence of welding failure.

[0036] The following describes a case where the shank 8 is replaced with the shank 9, which is longer than the shank 8.

[0037] The shank 8 with the cap tip 10 is removed from the state illustrated in FIG. 1, and the new shank 9 is installed as a replacement. If the shank 9 is attached as is, the cap tip 10 will be positioned higher by the length of the shank 9 longer than the shank 8 and will be farther away from the tip of the cooling pipe 11. As a result, the inside of the cap tip 10 is less likely to be exposed to fresh cooling water, and the cooling effect of the cap tip 10 is inferior to that with the shank 8.

[0038] In the present invention, as illustrated in FIG. 2, the bolt 4 is loosened and the cooling pipe support member 2 is moved upward by the length of the shank 9 longer than the shank 8, and then the bolt 4 is tightened to fix the straight holder 3 at this position. Although the shank 9 is longer than the shank 8, the position of the tip of the cooling pipe 11 has been moved upward by the length of the shank 9 longer than the shank 8, making the positional relationship between the inside of the cap tip 10 and the tip of the cooling pipe 11 same as that of the shank 8, resulting in sufficient cooling.

[0039] Accordingly, even the lengths of the shanks 8 and 9 are different, the distance between the inside of the cap tip 10 and the tip of the cooling pipe 11 can be brought closer together for efficient cooling in either case. In addition, the position of the cooling pipe 11 can be changed easily and accurately.

[0040] The second embodiment is now described with reference to FIG. 3 to FIG. 5.

[0041] In FIG. 3, 21 is a device body that includes a cooling pipe support member 20 and a straight holder 25. The cooling pipe support member 20 includes: a base 22 that supports the base end of a cooling pipe 26, and a fixing member 23 that is fixed to a lower part of a straight holder 25 separately from the base 22 and that penetrates and supports the cooling pipe 26. A supply port 22a for the cooling water is provided on the side face of the base 22, and a discharge port 23a for the cooling water is provided on the side face of the fixing member 23.

[0042] The lower part of the fixing member 23 is provided with a lock mechanism 30 having a ring-type steel pipe joint structure that uses an annular compression ring 28 to fix the cooling pipe 26 in any position, so that the cooling pipe support member 20 is movable in the axial direction of the straight holder 25 and fixable at any position.

[0043] The following describes the lock mechanism 30.

[0044] As illustrated in FIG. 5, the base end of the fixing member 23 to which the straight holder 25 is attached has a small diameter portion 23b, and the base end of a through hole 23c, which has a slightly larger diameter than that of the cooling pipe 26, has a slant portion 23d in an arc shape corresponding to the outer peripheral arc of the annular compression ring 28. The fixing member 23 has a threaded portion 23e formed on the outer surface of the base end, and the threaded portion 23e can be screwed into a nut member 27, which is U-shaped in section and has an inner side surface serving as a threaded portion 27a. The cooling pipe 26 penetrates through the fixing member 23, the compression ring 28, and the nut member 27. The nut member 27 moves to the base end of the fixing member 23 by tightening the nut member 27, so that the compression ring 28 is fixed tightly to the cooling pipe 26, thereby firmly fixing the cooling pipe 26 and maintaining airtightness. On the other hand, by loosening the nut member 27, the compression ring 28 is released from the tight contact, allowing the fixing member 23 to move freely in the vertical direction. Note that 29 is an O-ring that has a hollow body to maintain airtightness.

[0045] The following describes a case where the shank 8 is replaced with the shank 9, which is longer than the shank 8.

[0046] In the state illustrated in FIG. 3, if the new shank 9 in FIG. 4 is merely attached, the cap tip 10 is positioned higher by the length of the shank 9 longer than the shank 8, making the cooling effect of the cap tip 10 inferior to that with the shank 8, which is the same as the aforementioned embodiment.

[0047] In a second embodiment, as illustrated in FIG. 4, after a nut member 27 is loosened and the compression ring 28 is released from the tight contact, a base 22 is moved upward by the length of the shank 9 longer than the shank 8, and then the nut member 27 is tightened to fix the fixing member 23 at this position. Although the shank 9 is longer than the shank 8, the position of the tip of the cooling pipe 26 has been moved upward by the length of the shank 9 longer than the shank 8. Therefore, the position relationship between the inside of the cap tip 10 and the tip of the cooling pipe 26 is the same as that of the shank 8, resulting in sufficient cooling.

[0048] Accordingly, even the lengths of the shanks 8 and 9 are different, the positional relationship between the inside of the cap tip 10 and the tip of the cooling pipe 26 can be made closer for efficient cooling in either case. In addition, the position of the base 22 can be changed easily and accurately only by loosening or tightening the nut member 27 of the lock mechanism 30.

[0049] As is obvious from the above description, the present invention is a resistance welding electrode device with a structure in which the electrode is cooled with cooling water, and the electrode attached to the cooling pipe is movable in the axial direction, allowing the discretionary positional adjustment of a water-cooling end inside the inner face of the electrode in a very simple manner, efficient circulation of cooling water to the proximity of the tip of the electrode, thereby maintaining the form of the electrode tip stably for a long period of time, reducing occurrence of welding failure. In addition, the electrode position can be adjusted easily and accurately by moving the straight holder.

REFERENCE SIGNS LIST

[0050] 1 device body [0051] 2 cooling pipe support member [0052] 2a base portion [0053] 2b supply port [0054] 2c communicating tube [0055] 2d long groove [0056] 2e cylindrical body [0057] 3 straight holder [0058] 3a through hole [0059] 3b large diameter portion [0060] 3c large diameter portion [0061] 3d discharge port [0062] 4 locking bolt [0063] 5 connector [0064] 6 connector [0065] 7 electrode [0066] 8 shank [0067] 8a through hole [0068] 9 shank [0069] 9a through hole [0070] 10 cap tip [0071] 10a mounting hole [0072] 11 cooling pipe [0073] 11A tip opening [0074] 20 cooling pipe support member [0075] 21 device body [0076] 22 base [0077] 22a supply port [0078] 23 fixing member [0079] 23a discharge port [0080] 23b small diameter portion [0081] 23c through hole [0082] 23d slant portion [0083] 23e threaded portion [0084] 25 straight holder [0085] 26 cooling pipe [0086] 27 nut member [0087] 27a threaded portion [0088] 27b through hole [0089] 27c slant face [0090] 28 compression ring [0091] 29 O-ring [0092] 30 lock mechanism [0093] 51 holder [0094] 52 shank [0095] 53 cap tip [0096] 54 cooling pipe