JP5967444B2 - Method for manufacturing guide pin for electric resistance welding electrode - Google Patents

Description

  In this invention, the guide hole having a circular section in the electrode is composed of at least a large-diameter hole and a small-diameter hole, and the guide pin fitted in the guide hole is slidable with substantially no gap in the large-diameter hole. In particular, the present invention relates to an electrode for electric resistance welding of a type composed of a guide portion which is a large-diameter portion fitted in and a small-diameter portion which penetrates the small-diameter hole, and in particular, a guide which is fitted into the electrode guide hole. The present invention relates to a method of manufacturing a pin.

  In Japanese Patent No. 2903149, the guide hole having a circular cross section in the electrode is composed of at least a large diameter hole and a small diameter hole, and the guide pin fitted into the guide hole has substantially no gap in the large diameter hole. An electrode for electric resistance welding of a type composed of a guide portion which is a large diameter portion fitted in a slidable state and a small diameter portion penetrating the small diameter hole is described, and further, an end portion of the small diameter portion The bolt is integrally provided, and the nut is tightened by penetrating the bolt through the guide portion made of synthetic resin. The small diameter portion of the guide pin is press-fitted into the hole of the synthetic resin guide portion.

  In Japanese Patent No. 3716369, a circular guide hole in an electrode is composed of at least a large-diameter hole and a small-diameter hole, and a guide pin fitted into the guide hole has a substantially gap in the large-diameter hole. There is described an electrode for electric resistance welding of a type composed of a guide portion which is a large diameter portion fitted in a slidable state and a small diameter portion penetrating the small diameter hole, and further made of a synthetic resin. It is described that the small-diameter portion made of metal is cast into the configured guide portion, that is, a method is adopted in which the small-diameter portion is set at a predetermined position of the mold and the synthetic resin is poured therein. .

Japanese Patent No. 2903149 Japanese Patent No. 3716369

  In the technique described in Patent Document 1, the guide portion and the small diameter portion are integrated with a so-called bolt / nut structure, but the small diameter portion is press-fitted into the hole of the synthetic resin guide portion. The synthetic resin is deformed with the press-fitting, and the outer peripheral surface of the guide portion does not become an accurate cylindrical surface. Therefore, there exists a problem that a guide part does not advance / retreat smoothly within the large diameter hole of an electrode.

  In the technique described in Patent Document 2, the guide portion and the small diameter portion are integrated by a so-called casting method. Therefore, when the fluid synthetic resin injected at a high temperature is cured, the guide portion Different dimensions of shrinkage occur in each part of the. For this reason, the outer peripheral surface of a guide part does not become an exact cylindrical surface. Therefore, there exists a problem that a guide part does not advance / retreat smoothly within the large diameter hole of an electrode.

  The present invention has been provided to solve the above-described problems, and can ensure a smooth forward / backward movement, and can solve the problems peculiar to guide pins formed by combining different types of materials. It aims at providing the manufacturing method of this.

The invention described in claim 1 is directed to a guide pin that is fitted into a guide hole of an electrode having a circular cross-section that is composed of at least a large-diameter hole and a small-diameter hole, and the guide pin fitted into the guide hole includes: A guide portion that is a large-diameter portion that is fitted in the large-diameter hole with substantially no gap and is slidable, and a small-diameter portion that passes through the small-diameter hole, and the guide pin The guide portion is made of a synthetic resin material and is provided with at least an insertion small-diameter hole so that the end surface of the guide portion is in close contact with the inner end surface of the large-diameter hole and performs an on-off valve function. The small-diameter portion is made of a heat-resistant hard material such as a metal material or a ceramic material, and has a shaft portion that is inserted into the insertion small-diameter hole, and after the shaft portion is press-fitted into the insertion small-diameter hole ,guide Including the enlarged diameter portion formed on the outer peripheral surface have rows finishing the cylindrical over the entire length of the guide portion of the, then, the so that vertical positional relation to the axis of the cylinder of the finished guide portion An end face is processed . A method for producing a guide pin for an electric resistance welding electrode.

  A guide pin for an electric resistance welding electrode that welds a projection nut to a steel plate part needs to perform an insulating function until the advance pressure of the counterpart electrode reaches a predetermined location. On the other hand, the small-diameter portion of the guide pin needs to be made of a heat-resistant hard material having excellent heat resistance and wear resistance. In order to satisfy these requirements, it is desirable to press-fit the shaft portion of the small diameter portion into the insertion small diameter hole of the synthetic resin guide portion, but since the guide portion side is made of synthetic resin, It is inevitable that the outer shape of the guide portion is locally expanded or recessed. That is, there is a difference in the diameter of the guide portion when viewed in the axial direction. If an electrode large-diameter hole that allows such a dimensional difference is opened, the axis of the guide pin swings with respect to the electrode axis when the guide pin advances and retracts, and the function of positioning the small-diameter portion is not fulfilled. It will be. When the guide pin for the electric resistance welding electrode is formed using the heat-resistant hard material constituting the small-diameter portion and the synthetic resin material constituting the guide portion, which are different materials as described above, a peculiarity generated between the two materials. It is important to consider that this phenomenon does not impair the original function of the electric resistance welding electrode.

  In the present invention, the guide portion of the guide pin is made of a synthetic resin material, and at least an insertion small-diameter hole is provided, and the small-diameter portion of the guide pin is made of a heat-resistant hard material such as a metal material or a ceramic material. And a shaft portion that is inserted into the insertion small-diameter hole, and after the shaft portion is press-fitted into the insertion small-diameter hole, the outer peripheral surface of the guide portion is finished into a cylindrical shape. As described above, after the guide portion and the small-diameter portion are integrated by press fitting, the dimensional deviation appearing on the outer surface of the guide portion is removed by finishing, so the guide portion has a highly accurate cylindrical shape. Finished, the forward and backward sliding with respect to the electrode large-diameter hole is accurately achieved. In other words, it is possible to ensure that the large-diameter hole is fitted in a slidable state with substantially no gap, so that the guide pin can accurately move back and forth on the electrode axis, and the centering function of the guide pin can be improved. Surely fulfilled.

The invention according to claim 2 is directed to a guide pin fitted into a guide hole of an electrode having a circular cross section composed of at least a large-diameter hole and a small-diameter hole, and the guide pin fitted into the guide hole includes: A guide portion that is a large-diameter portion that is fitted in the large-diameter hole with substantially no gap and is slidable, and a small-diameter portion that passes through the small-diameter hole, and the guide pin The guide portion is made of a synthetic resin material, and the end surface of the guide portion is in close contact with the inner end surface of the large-diameter hole so as to perform an on-off valve function. The small-diameter portion of the guide pin is made of a metal material, a ceramic material, or the like is composed of a refractory hard material, said after cast a small-diameter portion to the guide portion, have rows finishing into a cylindrical shape, including a reduced diameter portion formed on the outer peripheral surface over the entire length of the guide portion of the guide portion, then Finished moth An electrical resistance welding electrode guide pin manufacturing method, which comprises processing the end face so as to be perpendicular positional relationship with respect to the axis of the cylinder of de unit.

  A guide pin for an electric resistance welding electrode that welds a projection nut to a steel plate part needs to perform an insulating function until the advance pressure of the counterpart electrode reaches a predetermined location. On the other hand, the small-diameter portion of the guide pin needs to be made of a heat-resistant hard material having excellent heat resistance and wear resistance. In order to satisfy these requirements, it is desirable to cast the small-diameter portion into the synthetic resin guide portion. However, since the guide portion side is made of synthetic resin, the synthetic resin is partially heated by cooling after casting. Shrinkage occurs, and it is inevitable that the outer shape of the guide portion is locally recessed or swollen. That is, there is a difference in the diameter of the guide portion when viewed in the axial direction. If an electrode large-diameter hole that allows such a dimensional difference is opened, the axis of the guide pin swings with respect to the electrode axis when the guide pin advances and retracts, and the function of positioning the small-diameter portion is not fulfilled. It will be. When the guide pin for the electric resistance welding electrode is formed using the heat-resistant hard material constituting the small-diameter portion and the synthetic resin material constituting the guide portion, which are different materials as described above, a peculiarity generated between the two materials. It is important to consider that this phenomenon does not impair the original function of the electric resistance welding electrode.

  In the present invention, the guide portion of the guide pin is made of a synthetic resin material, and the small diameter portion of the guide pin is made of a heat-resistant hard material such as a metal material or a ceramic material, and is cast by the guide portion. In this manufacturing method, after the casting, the outer peripheral surface of the guide portion is finished into a cylindrical shape. As described above, after the guide portion and the small-diameter portion are integrated by casting, the dimensional deviation appearing on the outer surface of the guide portion is removed by finishing, so the guide portion has a highly accurate cylindrical shape. Finished, the forward and backward sliding with respect to the electrode large-diameter hole is accurately achieved. In other words, it is possible to ensure that the large-diameter hole is fitted in a slidable state with substantially no gap, so that the guide pin can accurately move back and forth on the electrode axis, and the centering function of the guide pin can be improved. Surely fulfilled.

  Further, when the air passage is formed after the finishing process, the flow passage area of the air passage can be set accurately, and an optimal air flow rate can be ensured for spatter removal, cooling, and the like. That is, an air passage having an accurate flow path area as described above is formed by machining and molding an air passage such as a flat portion or a groove in the axial direction on a straight cylindrical surface finished to a predetermined diameter when viewed in the axial direction. It is possible to obtain a passage. Alternatively, even when an end face for interrupting air flow in the air passage is formed, the end face processing can be performed with reference to the accurately finished cylindrical face, so that the shape of the entire guide portion is required with high accuracy. .

  The above-described processing of the air passage and the end face can exist as an invention independent of the invention described in the first and second aspects.

It is sectional drawing of the whole electrode. It is sectional drawing etc. of the components state of a guide pin. It is sectional drawing which shows the modification of an air passage. It is sectional drawing which shows the press fit state of a small diameter part. It is process drawing which shows finishing. It is process drawing which shows the other finishing process example. It is process drawing which shows another example of finishing processing. It is sectional drawing of the electrode which shows another guide pin.

  Below, the form for enforcing the manufacturing method of the guide pin for electrical resistance welding electrodes of this invention is demonstrated.

  First, the electrode structure will be described with reference to FIGS.

  First, the electrode body will be described.

  The electrode body 1 made of a copper alloy has a cylindrical shape, and a fixing portion 2 to be inserted into a stationary member (not shown) and a cap portion 4 on which the steel plate component 3 is placed are coupled at a screw portion 5. ing. A guide hole 6 having a circular cross section is formed in the electrode body 1, and the guide hole 6 is constituted by at least a large diameter hole 7 and a small diameter hole 8 opened at the center of the cap portion 4.

  A tapered portion 9 is formed in the lower portion of the fixed portion 2, and the tapered portion 9 is fitted into a tapered hole provided in the stationary member. A vent 10 for introducing compressed air into the guide hole 6 is provided on the side of the fixed part 2.

  Next, the guide pin will be described.

  The guide pin 12 includes a large-diameter portion that is fitted in the large-diameter hole 7 so as to be slidable with substantially no gap, that is, a guide portion 13 and a small-diameter portion 14 that penetrates the small-diameter hole 8. It is configured. The guide portion 13 is a large diameter portion made of a synthetic resin excellent in heat resistance, for example, polytetrafluoroethylene (trade name: Teflon).

  The guide portion 13 which is a large diameter portion is also circular in cross section, and an insertion large diameter hole 15 and an insertion small diameter hole 16 are formed in a state of being continuous with the central portion. The small-diameter portion 14 is made of a heat-resistant hard material such as a metal material such as stainless steel or a ceramic material, and penetrates the flange portion 17 inserted into the insertion large-diameter hole 15 and the insertion small-diameter hole 16. It is comprised by the axial part 18 inserted. A pressure-receiving end surface 19 is formed at the boundary between the insertion large-diameter hole 15 and the insertion small-diameter hole 16, and the end surface of the flange portion 17 is configured to be in close contact.

  An end surface 11 is formed at the end of the guide portion 13, and the end surface 11 is in close contact with the inner end surface 24 of the large-diameter hole 7. The end surface 11 and the inner end surface 24 are planar surfaces that are orthogonal to the axis of the guide pin 12 and that annularly surround the axis of the guide pin 12.

  A positioning pin 21 is formed at the end of the shaft portion 18 via a taper portion 20 so that a screw hole of an iron projection nut 22 matches the positioning pin 21. Reference numeral 23 denotes a movable electrode corresponding to the electrode body 1. A pilot hole 3 a is formed in the steel plate part 3, and the shaft portion 18 passes through the hole 3 a to position the steel plate part 3.

  Next, the dimensions of each part of the guide pin will be described.

  The diameter of the shaft 18 is 9 mm, the length of the shaft 18 is 35 mm, the diameter of the flange 17 is 14 mm, the thickness of the flange 17 is 2.8 mm, the inner diameter of the large insertion hole 15 is 14.2 mm, and the small insertion diameter The inner diameter of the hole 16 is 8.6 mm, the total length of the guide portion 13 in the axial direction is 33 mm, the diameter of the guide portion 13 is 20.2 mm, and the length of the insertion large-diameter hole 15 is 16 mm.

  Due to the above dimensions, the shaft portion 18 of the small diameter portion 14 inserted through the guide portion 13 is press-fitted into the insertion small diameter hole 16. The flange portion 17 is inserted into the insertion large-diameter hole 15 with a slight gap. The end surface of the flange portion 17 is in close contact with the pressure receiving end surface 19.

  Next, the dimensional state of the large-diameter hole will be described.

  The large-diameter hole 7 is formed from both the fixed portion 2 to the cap portion 4. The guide portion 13 is fitted into the large-diameter hole 7 formed in the fixed portion 2 in a state in which the guide portion 13 can be slid substantially without a gap, and the fitted sliding section has a large insertion diameter. The section corresponds to the axial length of the hole 15 and is indicated by a symbol L1 in FIG.

  The synthetic resin material between the pressure receiving end surface 19 and the end surface 11 is a synthetic resin material sandwiched between the flange portion 17 of the small diameter portion 14 and the inner end surface 24 of the large diameter hole 7, and this material section Is indicated by the symbol L2 in FIG. The inner diameter of the large-diameter hole 7 surrounding the section L2 is a large-diameter portion 26 provided with a gap 25.

  Next, the air passage will be described.

  As shown in FIGS. 1, 2, etc., the air passage 27 is configured by forming four axial portions 28 on the surface of the guide portion 13. Further, a gap 29 through which compressed air passes is formed between the shaft portion 18 and the small diameter hole 8. When the guide pin 12 is pushed down by the advancement of the movable electrode 23, the end face 11 is separated from the inner end face 24, and an air circulation gap is formed. That is, the close contact portion between the end face 11 and the inner end face 24 functions as an on-off valve. The compressed air that has entered through the air vent 10 is prevented from cooling the welded portion of the nut 22 and entering the spatter through the air passage 27, between the end face 11 and the inner end face 24, through the gap 29.

  A compression coil spring 30 is fitted between the flange portion 17 and the inner bottom surface of the guide hole 6, the tension acts on the flange portion 17, and the small diameter portion 14 is pressed in the direction of entering the guide portion 13. Reference numeral 31 denotes an insulating sheet fitted into the inner bottom surface of the guide hole 6. The pressing force acting on the flange portion 17 is ensured by the pressure of the compressed air and the tension of the compression coil spring 30, but may be either one.

  Next, a modified example of the air passage will be described.

  In the example shown in FIG. 3, eight through holes 32 in the axial direction are provided near the outer periphery of the guide portion 13, and the upper end portion thereof is open to the end surface 11. That is, the through hole 32 is an air passage. Further, the air passage shown in FIG. 2C is provided with eight axial grooves 33 on the outer peripheral surface of the guide portion 13, and the upper end portion thereof is open to the end surface 11. That is, the concave groove 33 is an air passage.

  Next, a modified example of the small diameter portion press-fitting will be described.

  In the small diameter portion 14 shown in FIG. 4A, a circumferential groove portion 34 is formed adjacent to the flange portion 17. This is configured such that a portion adjacent to the flange portion 17 has a small diameter. When such a small diameter portion 14 is press-fitted into the insertion small diameter hole 16, a bulging portion 35 as shown in FIG. As described above, since the shaft portion 18 has a diameter of 9 mm and the insertion small-diameter hole 16 has an inner diameter of 8.6 mm, the shaft portion 18 is press-fitted into the insertion small-diameter hole 16. A bulging portion 35 is formed by bulging into the concave groove 34.

  By forming such a bulging portion 35, the bulging portion 35 is caught by the corner portion 36 of the concave groove 34 even if a force in the pulling direction is excessively applied to the small diameter portion 14. There is an effect that it does not come out. In addition, what is shown to the figure (C) is the example which has arrange | positioned the ditch | groove 34 in the intermediate part of the axial part 18, and the effect of the swelling part 35 etc. is the same as the previous thing.

  In the above description, the shaft portion 18 is press-fitted only into the insertion small-diameter hole 16, and the flange portion 17 is not press-fitted into the insertion large-diameter hole 15. Therefore, in claim 1, the hole formed in the guide portion 13 is expressed as "... at least an insertion small diameter hole is provided,".

  Below, the manufacturing method of a guide pin is demonstrated according to FIGS.

  FIG. 5A is a cross-sectional view showing the shape of the material state of the guide portion 13. FIG. 5B shows a state in which the small diameter portion 14 is press-fitted into the insertion small diameter hole 16 and the flange portion 17 is in close contact with the pressure receiving end surface 19. In this state, since the small-diameter portion 14 is press-fitted, the guide portion 13 becomes a diameter-expanded portion indicated by reference numeral 37 with the diameter of the press-fitted portion being increased. The diameter of the shaft portion 18 of the small diameter portion 14 is 9 mm as described above, and the inner diameter of the insertion small diameter hole 16 is 8.6 mm as described above. Because of such a dimensional relationship, the diameter of the enlarged diameter portion 37 is 20.6 mm, and the diameter below the flange portion 17 that has not been enlarged is 20.2 mm.

  Therefore, the diameter-enlarged portion 37 is removed by cutting finishing to obtain a straight cylindrical shape, and further, stepped machining is performed as necessary to form the end face 11, and then the planar portion 28 is machined. In addition, you may process the plane part 28 before a step part process. The removal of the enlarged diameter portion 37 is 0.4 mm. However, in order to obtain a straight cylindrical surface over the entire length of the guide portion 13, it is desirable that the removal amount is slightly larger than 0.4 mm. A two-dot chain line on the center side in FIG. 5B indicates a finishing line. The diameter of the guide portion 13 after the small diameter portion 14 is press-fitted is set to be larger than that of the large diameter hole 7, and the diameter of the finishing line can be properly slid with respect to the large diameter hole 7. Has been. Since the step portion processing obtains a plane perpendicular to the cylindrical axis of the guide portion 13 finished with high accuracy, the relative position of the end surface 11 with respect to the axis of the guide pin 13 is set accurately. Although FIG. 5 is a cross-sectional view, hatching and satin are not shown for easy viewing.

  Therefore, the manufacturing method of the guide pin 12 in the case of having the flange portion 17 presses the small diameter portion 14 into the guide portion 13 in the material state, and then removes the enlarged diameter portion 37 by cutting. During this removal process, the portion below the flange portion 17 is also slightly cut to obtain a straight cylindrical outer shape having a uniform diameter over the entire length of the guide portion 13.

  By performing such finishing, the dimensional problem caused by the small-diameter portion 14 made of a heat-resistant hard material being press-fitted into the guide portion 13 made of synthetic resin is solved. That is, since the guide portion 13 that is straight and has high dimensional accuracy is ensured, it can be fitted in a state in which it can slide with substantially no gap, and can slide accurately and smoothly in the large-diameter hole 7.・ It is possible to move forward and backward.

  Next, another method for manufacturing the guide pin will be described.

  In the example shown in FIG. 6, a bolt 46 is integrally formed at the lower end of the small-diameter portion 14, and when the shaft portion 18 is press-fitted into the insertion small-diameter hole 16, the bolt 46 passes through the bolt hole 47, and there is a washer 48. The small diameter portion 14 and the guide portion 13 are integrated by assembling the nut 49. The dimensional state, processing order, and the like are the same as in the example shown in FIG. 5, and members having similar functions are denoted by the same reference numerals. Although FIG. 6 is a cross-sectional view, hatching and satin are not shown for easy viewing.

  Furthermore, another method for manufacturing the guide pin will be described.

  In the example shown in FIG. 7, the small diameter portion 14 having the flange portion 17 is set in a mold of a synthetic resin molding machine, and the guide portion 13 in a material state is molded by injection molding by injection molding. The same cutting process is performed. In this example, as shown in FIG. 7A, the portion of the synthetic resin having a large thickness has a large amount of shrinkage at the time of cooling. Therefore, the peripheral portion of the shaft portion 18 has a small diameter, and the peripheral portion of the flange portion 17 is large. It is a diameter. Reference numeral 50 denotes a reduced diameter portion. Although FIG. 7 is a cross-sectional view, hatching and satin are not shown for easy viewing.

  Next, the bolt electrode will be described.

  Although FIGS. 1-7 is a case where the projection nut 22 is made into object, in FIG. 8, the iron projection bolt 39 is made into object. The projection bolt 39 is constituted by a circular flange 40, a bolt shaft portion 41 formed integrally therewith, and a welding projection 42 formed on the flange 40.

  The small-diameter portion 14 has a tubular hollow structure provided with an insertion hole 43, and the bolt shaft portion 41 is inserted into the insertion hole 43. The length of the bolt shaft portion 41 is set to be longer than the depth of the insertion hole 43, the small diameter portion 14 protrudes from the upper surface of the cap portion 4, and when the steel plate component 3 is placed on the cap portion 4, The leading end protrudes from the prepared hole 44 of the steel plate part 3. The other configuration is the same as that of the previous example including a portion not shown, and the same reference numerals are described for members having similar functions.

  The state shown in the figure is a state in which the tip end portion of the small diameter portion 14 passes through the lower hole 44 of the steel plate part 3 and the bolt shaft portion 41 is inserted into the insertion hole 43, thereby the bolt shaft portion 41 and the lower hole 44. Is in a coaxial state. Here, when the movable electrode 23 advances, the tip of the bolt shaft portion 41 pushes down the bottom portion of the insertion hole 43, so that the entire guide pin 12 is pushed down and the small diameter portion 14 is pulled out from the lower hole 44. Further, when the pressurization of the movable electrode 23 proceeds, the welding protrusion 42 is pressurized to the steel plate part 3, and a welding current is applied to complete the welding. Thereafter, the steel plate part 3 is extracted from the insertion hole 43 together with the projection bolt 39.

  The operational effects of the first embodiment described above are as follows.

  The guide pin 12 for an electric resistance welding electrode that welds the projection nut 22 to the steel plate part 3 needs to perform an insulating function until the advance pressure of the counterpart electrode 23 reaches a predetermined position. On the other hand, the small-diameter portion 14 of the guide pin 12 needs to be made of a heat-resistant hard material having excellent heat resistance and wear resistance. In order to satisfy these requirements, it is desirable to press-fit the shaft portion 18 of the small diameter portion 14 into the insertion small diameter hole 16 of the synthetic resin guide portion 13, but the guide portion 13 side is made of synthetic resin. After the press-fitting of the shaft portion, it is inevitable that the outer shape of the guide portion 13 is locally expanded or recessed. That is, there is a difference in the diameter of the guide portion 13 when viewed in the axial direction. If the electrode large-diameter hole 7 that allows such a dimensional difference is opened, the axis of the guide pin 12 swings with respect to the electrode axis when the guide pin 12 advances and retracts, and the positioning function of the small-diameter portion 14 is determined. Will not be fulfilled. Thus, when the electric resistance welding electrode guide pin 12 is formed using the heat-resistant hard material constituting the small-diameter portion 14 and the synthetic resin material constituting the guide portion 13, which are different materials, between the two materials. It is important to consider that the specific phenomenon that occurs does not impair the original function of the electric resistance welding electrode.

  In this embodiment, the guide portion 13 of the guide pin 12 is made of a synthetic resin material, and at least an insertion small-diameter hole 16 is provided. The small-diameter portion 14 of the guide pin 12 is made of a heat resistant material such as a metal material or a ceramic material. The shaft portion 18 is made of a hard material and is inserted into the insertion small-diameter hole 16. After the shaft portion 18 is press-fitted into the insertion small-diameter hole 16, the outer peripheral surface of the guide portion 13 is cylindrical. This is a manufacturing method for performing finishing. As described above, after the guide portion 13 and the small diameter portion 14 are integrated by press-fitting, the dimensional deviation appearing on the outer surface of the guide portion 13 is removed by finishing, so the guide portion 13 is highly accurate. Thus, the forward / backward sliding with respect to the electrode large-diameter hole 7 is accurately achieved. That is, since it can be ensured that the large-diameter hole 7 is fitted in a slidable state with substantially no gap, the guide pin 12 can accurately advance and retreat on the electrode axis line. The centering function is performed reliably.

  The guide pin 12 for an electric resistance welding electrode that welds the projection nut 22 to the steel plate part 3 needs to perform an insulating function until the advance pressure of the counterpart electrode 23 reaches a predetermined position. On the other hand, the small-diameter portion 14 of the guide pin 12 needs to be made of a heat-resistant hard material having excellent heat resistance and wear resistance. In order to satisfy these requirements, it is desirable to cast the small-diameter portion 14 into the synthetic resin guide portion 13. However, since the guide portion 13 side is made of synthetic resin, the synthetic resin is partially cooled by cooling after casting. It is inevitable that the heat shrinkage occurs and the outer shape of the guide portion 13 is locally recessed or swollen. That is, there is a difference in the diameter of the guide portion 13 when viewed in the axial direction. If the electrode large-diameter hole 7 that allows such a dimensional difference is opened, the axis of the guide pin 12 swings with respect to the electrode axis when the guide pin 12 advances and retracts, and the positioning function of the small-diameter portion 14 is determined. Will not be fulfilled. Thus, when the electric resistance welding electrode guide pin 12 is formed using the heat-resistant hard material constituting the small-diameter portion 14 and the synthetic resin material constituting the guide portion 13, which are different materials, between the two materials. It is important to consider that the specific phenomenon that occurs does not impair the original function of the electric resistance welding electrode.

  In the present embodiment, the guide portion 13 of the guide pin 12 is made of a synthetic resin material, and the small-diameter portion 14 of the guide pin 12 is made of a heat-resistant hard material such as a metal material or a ceramic material. This is a manufacturing method in which after the casting, the outer peripheral surface of the guide portion 13 is finished into a cylindrical shape. As described above, after the guide portion 13 and the small-diameter portion 14 are integrated by casting, the dimensional deviation appearing on the outer surface of the guide portion 13 is removed by finishing processing. Thus, the forward / backward sliding with respect to the electrode large-diameter hole 7 is accurately achieved. That is, since it can be ensured that the large-diameter hole 7 is fitted in a slidable state with substantially no gap, the guide pin 12 can accurately advance and retreat on the electrode axis line. The centering function is performed reliably.

  Further, when the air passage 27 and the concave groove 33 are formed by cutting or the like after the above-described finishing process, the flow passage areas of the air passage 27 and the concave groove 33 can be set accurately, and spatter removal or cooling can be performed. It is possible to ensure an optimal air flow rate for the like. That is, the air passage 27 and the concave groove 33 such as a plane portion and a concave groove are processed and molded in a straight cylindrical surface finished to a predetermined diameter when viewed in the axial direction, thereby accurately It is possible to obtain an air flow path having a flow path area. Alternatively, even when the end surface 11 for interrupting the air flow in the air flow path is formed, the end surface processing can be performed on the basis of the accurately finished cylindrical surface, so that the shape of the entire guide portion 13 is accurate. It is often requested.

  As described above, according to the manufacturing method of the present invention, it is possible to obtain a guide pin for an electric resistance welding electrode that can ensure a smooth forward / backward movement and can solve problems peculiar to a guide pin formed by combining different materials. Therefore, a highly reliable electrode structure can be ensured, and it can be used in a wide range of industrial fields such as automobile body welding processes and home appliance sheet metal welding processes.

DESCRIPTION OF SYMBOLS 1 Electrode main body 3 Steel plate part 3a Pilot hole 6 Guide hole 7 Large diameter hole 8 Small diameter hole 11 End surface 12 Guide pin 13 Guide part, Large diameter part 14 Small diameter part 15 Insertion large diameter hole 16 Insertion small diameter hole 17 Flange part 18 Shaft part 22 Projection nut 24 Inner end face 27 Air passage 29 Clearance 32 Through hole (air passage)
33 Groove (air passage)
39 Projection Bolt 43 Insertion Hole 44 Pilot Hole

Claims (2)

It is intended for a guide pin that fits into a guide hole of an electrode having a circular cross-section that is composed of at least a large-diameter hole and a small-diameter hole, and the guide pin that fits into the guide hole is substantially within the large-diameter hole. The guide portion is a large-diameter portion that is fitted in a slidable state without any gap, and the small-diameter portion that penetrates the small-diameter hole, and the guide portion of the guide pin is made of a synthetic resin material. And at least an insertion small-diameter hole is provided, and the end surface of the guide portion is in close contact with the inner end surface of the large-diameter hole so as to perform an on-off valve function, and the small-diameter portion of the guide pin is made of a metal material or It is made of a heat-resistant hard material such as a ceramic material and has a shaft portion that is inserted into the insertion small-diameter hole, and is formed on the outer peripheral surface of the guide portion after the shaft portion is press-fitted into the insertion small-diameter hole. Was Characterized in that the diameter have rows finishing the cylindrical over the entire length of the guide portion including, then processing the end surface such that the vertical position relationship with respect to the axis of the cylinder of the finished guide portion A method of manufacturing a guide pin for an electric resistance welding electrode. It is intended for a guide pin that fits into a guide hole of an electrode having a circular cross-section that is composed of at least a large-diameter hole and a small-diameter hole, and the guide pin that fits into the guide hole is substantially within the large-diameter hole. The guide portion is a large-diameter portion that is fitted in a slidable state without any gap, and the small-diameter portion that penetrates the small-diameter hole, and the guide portion of the guide pin is made of a synthetic resin material. Configured, the end surface of the guide portion is configured to be in close contact with the inner end surface of the large-diameter hole and serve as an on-off valve function, and the small-diameter portion of the guide pin is configured of a heat-resistant hard material such as a metal material or a ceramic material, after cast the small-diameter portion to the guide portion, have rows finishing the cylindrical over the entire length of, including reduced diameter portion formed on the outer peripheral surface guide portion of the guide portion, then the finished guide portion cylinder Paired with the axis Method of manufacturing an electro-resistance welding electrode guide pins, characterized in that processing the end surface such that the vertical positional relationship Te.

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