Electrode tip for resistance-welding and electrode for resistance-welding

Abstract

To accelerate a temperature drop by accelerating thermal diffusion (heat drawing), to stabilize a heat generation temperature, to shorten a repetition cycle of welding work, and to improve productivity of the welding work.SOLUTION: The electrode tip for resistance-welding comprises: a connection part attached to a shank; and a heating part that pressurizes a workpiece, receives power to generate heat, and heats the workpiece. The connection part is divided into a plurality of legs, a fitting space is formed inside the legs, and the fitting space is a lower end opening to be put over the attaching end surface of the shank. Some legs of the electrode tip are attached to the shank, and the heating part of the electrode tip protrudes out of the shank.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an electrode tip for resistance welding and an electrode for resistance welding.

[0002] Resistance welding electrodes are used for resistance welding. As shown in Figure 10(a), resistance welding is a method in which two or more metal components (weld materials: workpieces) W to be welded are sandwiched between a pair of resistance welding electrodes E and pressure is applied while power is supplied to both electrodes E to heat them, and the current supplied to both electrodes E is passed through the workpieces W, generating Joule heat in the workpieces W and welding them together. There are various resistance welding methods, such as a method in which the two workpieces W to be joined are sandwiched between electrodes E from the left and right and welded while applying pressure, as shown in Figure 10(b), and a method in which the electrodes E are placed side by side and pressed against the workpieces W while welding while applying pressure, as shown in Figures 10(c) and (d). The shaded areas in Figures 10(a), (c), and (d) are nuggets. [Background technology]

[0003] Resistance welding is used in a variety of fields, including the automotive, electrical parts, and home appliance industries. The types of workpieces are also diverse, ranging from spot welding of steel plates to fusing of conductor wires.

[0004] Resistance welding electrodes come in two types: an integrated type, in which the electrode tip (electrode tip) A and shank (base metal) B are integrated, as shown in Figure 11(a), and a cap tip type, in which the electrode tip A is detachably attached to the shank B, making it possible to replace the electrode tip A, as shown in Figure 11(b).

[0005] In the case of one-piece electrodes, there are various methods for attaching (joining) the electrode tip to the shank, with press-fitting and brazing being the most common. There is also a joining method called the NDB method (defect-free joining). The NDB method is an abbreviation for Non-Defective Bonding, and is a method in which the copper for the shank is melted and solidified in a non-oxidizing atmosphere, and then directly joined to the electrode tip, which is made of copper-tungsten alloy (Cu-W), W, Mo, or other materials.

[0006] Copper alloys such as chromium copper, alumina-dispersed copper, and beryllium copper are commonly used as electrode tip materials. Copper alloys have extremely low electrical resistivity and high thermal conductivity, allowing for rapid temperature rise and fall, making them suitable for repeated welding of many metal components and resulting in high productivity. Furthermore, when the workpiece is made of iron or stainless steel, they do not react significantly with the workpiece, making them suitable as electrode materials for resistance welding.

[0007] Non-ferrous metals such as aluminum, magnesium, zinc, copper, and brass have low resistance and high thermal conductivity, making it difficult to generate the resistance heat required for welding, and therefore require a large current. Furthermore, the reaction between the non-ferrous metal and the electrode tip becomes more pronounced, reducing the number of times they can be used. The reaction products between the non-ferrous metal and the electrode tip can change the electrical resistivity, resulting in uneven joining quality. Metals like aluminum, which absorb oxygen from the air and easily form an oxide film on their surface, present the challenge of making it difficult to weld the workpieces together. Furthermore, these workpieces have a lower melting point and are more susceptible to oxidation than ferrous materials, so welding requires passing a large current through them in a short period of time.

[0008] Electrode tips used under such harsh conditions as those described above are not made of copper alloys because they do not have the high-temperature hardness required. Instead, tungsten (W) or molybdenum (Mo) is used as the electrode tip material, as these materials have excellent high-temperature hardness, little reaction with other metal components, high resistance, and low thermal conductivity.

[0009] W and Mo have advantages when welding, such as a stable shape, the ability to maintain current density, resistance to adhesion to the workpiece, and the ability to use heat generated by the electrode for welding. These metals therefore demonstrate excellent performance when welding workpieces or plated products that have low resistance and high thermal conductivity, and can contribute to extending the life of the electrode and improving production efficiency.

[0010] To compensate for the cooling performance, W and Mo-based materials are often used as cap tip types joined to a shank such as copper.

[0011] Regardless of the material of the electrode tip, it will have a limited lifespan and will be subject to oxidation wear (heat damage to the electrode), cracking, welding (sticking of the workpiece), spatter (dirt), etc. with use.

[0012] In resistance welding, power is supplied to the electrode for a predetermined time (energization time), then the power supply is stopped (paused), the electrode is allowed to dissipate heat, and once the electrode has cooled down to a predetermined temperature (cooled), the electrode is removed from the workpiece and the next workpiece is welded. This process is repeated to perform the welding work.

[0013] The temperature of the weld is determined by the difference between the heat generated by contact resistance and the heat dissipation. The amount of heat generated is governed by the current value, current density, current flow time, the force pressing the electrode against the workpiece, and the electrical resistivity of the workpiece. The amount of heat dissipation is governed by the volume, thermal conductivity, specific gravity, and specific heat of the workpiece, as well as the heat dissipation from the electrode.

[0014] When welding is repeated, the heat generated in the electrode's heat-generating part accumulates in the electrode, causing the electrode's temperature to rise. As the temperature rises, electrical resistance increases, the current flowing to the heat-generating part decreases, and heat generation efficiency decreases. In addition, as the temperature rises, it becomes more difficult for the heat-generating part to dissipate heat (heat dissipation) during cooling, so it takes time for the heat-generating part to cool down to the set temperature after power supply is stopped, which lengthens the repetitive cycle time of the welding work and reduces the efficiency of the welding work.

[0015] Conventionally, a temperature sensor (e.g., a radiation thermometer) is attached near the heat-generating part of the electrode to measure the temperature of the heat-generating part, and a control circuit controls the power supply to the electrode so that the measured temperature becomes the desired set value, thereby shortening the repetitive work. [Prior art documents] [Patent documents]

[0016] [Patent Document 1] Patent No. 6298247 [Patent Document 2] Patent No. 6453653 Summary of the Invention [Problem to be solved by the invention]

[0017] The present invention provides an electrode tip for resistance welding that can accelerate heat diffusion (heat dissipation) to promote temperature drop, stabilize the heat generation temperature, shorten the repetition cycle of welding work to improve welding work productivity, and has excellent pressure resistance when clamping a workpiece, and a resistance welding electrode with the electrode tip attached to a shank. [Means for solving the problem]

[0018] The resistance welding electrode tip of the present invention (hereinafter sometimes simply referred to as "electrode tip") comprises a connecting part that is attached to the shank and a heating part that contacts the workpiece to apply pressure to the workpiece and generates heat when power is supplied to heat the workpiece. The connecting part is the part that is attached to the shank and is branched into several legs. The legs are long and thin. There are fitting spaces inside the several legs, and the fitting spaces are open downward so that they can be fitted onto the mounting end of the shank.

[0019] The resistance welding electrode of the present invention has the electrode tip integrally or detachably attached (connected) to the shank, with several legs of the electrode tip attached to the shank and the heat-generating part of the electrode tip protruding outside the shank. [Effects of the Invention]

[0020] The electrode tip of the present invention has a connecting portion that connects to the shank and branches into several legs, which allows heat to be dissipated from each leg, accelerating the temperature drop (cooling) when power supply is stopped, shortening the repetitive welding cycle, and improving the workability of welding work.Since the next power supply can be resumed only after the temperature has dropped to a predetermined level due to heat dissipation, heat generation is also stabilized.

[0021] The resistance welding electrode of the present invention has the electrode tip attached to the shank, and thus has the characteristics of the electrode tip. In addition, since several branched legs are connected to the shank, attachment to the shank is stable, and pressure applied to the electrode is distributed among the several legs, improving pressure resistance. [Brief explanation of the drawings]

[0022] [Figure 1] 1A and 1B are a top perspective view, a bottom perspective view, and a BB arrow view of FIG. 1B, showing an example of an electrode chip of the present invention. [Figure 2] 10A and 10B are views showing another example of an electrode chip of the present invention, in which (a) is a perspective view from the top, (b) is a perspective view from the bottom, and (c) is a view taken along the arrow BB in (b). [Figure 3] 10A and 10B are views showing another example of an electrode chip of the present invention, in which (a) is a perspective view from the top, (b) is a perspective view from the bottom, and (c) is a view taken along the arrow BB in (b). [Figure 4] 1A is a plan view of an example of a resistance welding electrode of the present invention, FIG. 1B is an explanatory view of FIG. 1A when viewed from the arrow BB, FIG. 1C is an explanatory view of FIG. 1D when viewed from the arrow AA, and FIG. 1D is an explanatory view of FIG. 1A when viewed from the arrow DD. [Figure 5] 1A is a plan view of another example of a resistance welding electrode of the present invention, FIG. 1B is an explanatory view of the electrode as viewed from the arrow BB in FIG. 1A, FIG. 1C is an explanatory view of the electrode as viewed from the arrow AA in FIG. 1D, and FIG. 1D is an explanatory view of the electrode as viewed from the arrow DD in FIG. [Figure 6] 1A is a plan view of another example of a resistance welding electrode of the present invention, FIG. 1B is an explanatory view of the electrode as viewed from the arrow BB in FIG. 1A, FIG. 1C is an explanatory view of the electrode as viewed from the arrow AA in FIG. 1D, and FIG. 1D is an explanatory view of the electrode as viewed from the arrow DD in FIG. [Figure 7] FIG. 2(a) is a longitudinal cross-sectional view of an electrode tip of the present invention, and FIG. 2(b) is a longitudinal cross-sectional view of a shank that connects the electrode tip of FIG. [Figure 8] FIG. 2(a) is a longitudinal cross-sectional view of an electrode tip of the present invention, and FIG. 2(b) is a longitudinal cross-sectional view of a shank that connects the electrode tip of FIG. [Figure 9] FIG. 2(a) is a longitudinal cross-sectional view of an electrode tip of the present invention, and FIG. 2(b) is a longitudinal cross-sectional view of a shank that connects the electrode tip of FIG. [Figure 10]1(a) to 1(d) are explanatory diagrams of different examples of general-purpose resistance welding. [Figure 11] (a) is a side view of a conventional integrated electrode, and (b) is a side view of an example of a conventional cap tip electrode with the shank and electrode tip separated. [Figure 12] 10(a) to 10(e) are explanatory diagrams of examples of different tip shapes of electrode tips. DETAILED DESCRIPTION OF THE INVENTION

[0023] The electrode tip of the present invention can be used as an integrated type fixed to the shank or as a cap tip type replaceable on the shank. The resistance welding electrode of the present invention is an integrated type in which the electrode tip of the present invention is attached integrally to the shank or a cap tip type in which the electrode tip is replaceably attached, but in this embodiment, the integrated type will be described in detail and a detailed description of the cap tip type will be omitted.

[0024] (Electrode Chip Embodiment 1) An embodiment of the electrode tip of the present invention will be described with reference to FIGS. 1(a) to 1(c).

[0025] [Electrode tip] The electrode tip 1 in Figure 1(a) has a heating part 3 at one end (attachment side) in the longitudinal direction (axial direction) of a round bar-shaped tip substrate 2, and a connecting part 4 on the opposite side. The heating part 3 comes into contact with the workpieces to be joined, applies pressure to the workpieces, and generates heat when power is supplied. The connecting part 4 is the part that is attached to the shank 5 (Figures 4 to 6).

[0026] [Chip substrate material] The material of the tip substrate 2 (the material of the electrode tip 1) varies depending on the material of the workpiece to be resistance welded, but the same materials as those used for general-purpose electrode tips can be used. If the workpiece is made of iron or stainless steel, copper alloys such as chromium copper, alumina-dispersed copper, and beryllium copper, which do not react strongly with the workpiece, are suitable.

[0027] When the workpiece is a non-ferrous metal such as aluminum, magnesium, zinc, copper, or brass, tungsten (W), molybdenum (Mo), copper tungsten (30%Cu-70%W), silver tungsten (30%Ag-65%W), other heavy alloys, and chromium-copper alloys are suitable, as they have excellent high-temperature hardness, little reaction with other metal components, high resistance, and low thermal conductivity. When welding nickel workpieces, silver tungsten (30%Ag-65%W) is suitable due to its long life.

[0028] W and Mo are highly reactive with oxygen, and may react with oxygen in the atmosphere during resistance welding to form an oxide layer on the surface. The electrode tip 1 of the present invention can be coated with a tungsten carbide film or a molybdenum carbide film on the entire surface of the electrode tip 1 or at least the surface of the heating portion 3 to prevent it from easily reacting with oxygen in the air even at high temperatures. The film can be formed by carbonizing the entire surface of the electrode tip 1 or at least the surface of the heating portion 3 at several hundred degrees to form tungsten carbide or molybdenum carbide.

[0029] The material, coating, etc. of the chip substrate 2 are the same as those in the following embodiments.

[0030] [Connection part] The connecting portion 4 of the electrode chip 1 in FIGS. 1(a) to 1(c) branches into four legs 7 at the lower end of the rod-shaped tip substrate 2. The four legs 7 are formed at equal intervals around the circumferential direction of the tip substrate 2. The number of legs 7 can be any desired number, two or more. The legs 7 in FIGS. 1(a) to 1(c) have a uniform thickness along their entire length. The cross-sectional shape of the legs 7 is fan-shaped as shown in FIG. 1(c), but can also be other shapes, such as triangular or rectangular. The tip substrate 2 can have a shape other than a rod, such as a square rod. In this case, the heating portion 3 and connecting portion 4 can also have a square rod shape or other shapes. This also applies to the following embodiments.

[0031] [Heating section] The heating portion 3 in Figures 1(a) to 1(c) is a portion that comes into contact with the workpiece, applies pressure to the workpiece, and generates heat by supplying power to heat the workpiece. The heating portion 3 in Figures 1(a) to 1(c) is shaped like a round bar that is thinner than the outer diameter of the round bar-shaped tip substrate 2. The tip surface (heating surface) 3a in Figure 1(a) is flat, but it can also be shaped like a radius as in Figure 12(a), a dome as in Figure 12(b), a dome radius as in Figure 12(c), a cone flat as in Figure 12(d), a cone radius as in Figure 12(e), or other shapes. This also applies to the following embodiments.

[0032] [Mating space] A fitting space 8 is formed inside the four legs 7. The lower end of the fitting space 8 is an opening that opens toward the lower end 7a of the leg 7. The ceiling surface 8a of the fitting space 8 is curved in an arc (FIGS. 1(c), 4(b), and 7(a)). The shape of the ceiling surface 8a is formed in an arc to match the shape of the outer peripheral surface 14a of the protrusion 14 (FIGS. 7(b), 8(b), and 9(b)) at one axial end (the electrode tip mounting end) of the shank 5 that the fitting space 8 covers. When the ceiling surface 8a covers the protrusion 14, it comes into surface contact with the outer peripheral surface 14a of the protrusion 14. It is desirable to change the shape of the ceiling surface 8a to match the shape of the protrusion 14 so that it can come into surface contact with the outer peripheral surface 14a of the protrusion 14. This also applies to the following embodiments.

[0033] [Sensor mounting part] The outer periphery of the heating unit 3 has a sensor mounting portion 3b (Fig. 4(a)(b)) for mounting a temperature sensor S (Fig. 4(a)(b)(d)). The sensor mounting portion 3b protrudes outward from the outer periphery of the heating unit 3 and has a size and shape that allows the sensor S to be mounted. This also applies to the following embodiments.

[0034] [Temperature sensor] The temperature sensor S attached to the sensor attachment portion 3b is a general-purpose thermocouple or other temperature sensor (the same applies to the following embodiments). Lead wires L (FIGS. 4(a) and 4(d)) extending from the temperature sensor S are drawn to the outside of the heating portion.

[0035] (Electrode Chip Embodiment 2) [Electrode tip] 2(a) to 2(c) show the electrode chip 1 of embodiment 2. Like the electrode chip 1 of embodiment 1 (FIG. 1(a)), this electrode chip 1 has a connecting portion 4 at one axial end of a round bar-shaped chip substrate 2, and a heating portion 3 at the opposite end. The material of this chip substrate 2 can also be the same as the material of the chip substrate 2 of embodiment 1.

[0036] [Connection part] The connecting portion 4 in Figures 2(a) to (c) also has the lower end of the rod-shaped chip substrate 2 branched into four legs 7. The four legs 7 are formed at equal intervals around the circumference of the chip substrate 2. The number of legs 7 can be any desired number, two or more. The four legs 7 are formed at equal intervals around the circumference of the chip substrate 2. As shown in Figures 2(a) and (b), each leg 7 tapers from the base side toward the lower end 7a, and has a fan-shaped cross section as shown in Figure 2(c).

[0037] [Heating section] 2(a) to 2(c) is also the part that comes into contact with the workpiece, applies pressure to the workpiece, and generates heat by supplying power to heat the workpiece. The heating part 3 protrudes from the opposite side of the legs 7 and is shaped like a two-tiered round bar that is thinner than the outer diameter of the round bar-shaped tip substrate 2.

[0038] [Mating space] 2(a) to 2(c), the insides of the four legs 7 form fitting spaces 8, and the lower ends of the fitting spaces 8 form lower openings that open toward the lower ends 7a of the legs 7. The ceiling surface 8a of the fitting space 8 is curved in an arc to match the shape of the outer peripheral surface 14a of the protrusion 14 (FIGS. 5(b) and 5(c), and 8(b)) at one axial end of the shank 5, and is in surface contact with the outer peripheral surface 14a of the protrusion 14 when placed over the protrusion 14.

[0039] [Sensor mounting part] The sensor mounting portion 3b protrudes downward from the center of the ceiling surface 8a of the fitting space portion 8 (FIGS. 5(b) and 8(a)). The outer peripheral surface of the sensor mounting portion 3b opens to the outer peripheral surface of the heating portion 3 as shown in FIG. 5(d).

[0040] [Temperature sensor] As shown in Figures 5(b) and 5(d), a temperature sensor S is attached to the sensor attachment section 3b. A lead wire L (Figure 5(b)) extending from the temperature sensor S is led out of the heating section 3 through an opening 3c (Figure 5(d)) of the sensor attachment section 3b.

[0041] (Electrode Chip Embodiment 3) [Electrode tip] 3(a) to 3(c) show the electrode chip 1 of embodiment 3. Like the electrode chip 1 of embodiment 1, this electrode chip 1 has a connecting portion 4 on one axial end side of a round bar-shaped chip substrate 2, and a heating portion 3 on the opposite side. The material of this chip substrate 2 can be the same as the material of the chip substrate 2 of embodiment 1.

[0042] [Connection part] The connecting portion 4 in Figures 3(a) to (c) also has the lower end of the rod-shaped chip substrate 2 branched into four legs 7. The four legs 7 are formed at equal intervals around the circumference of the chip substrate 2. The number of legs 7 can be any desired number greater than or equal to two. Each leg 7 tapers from the base side toward the lower end 7a as shown in Figures 3(a) and 3(b), and has a sectorial cross-sectional shape as shown in Figure 3(c).

[0043] [Heating section] 3(a) to 3(c) also contacts the workpiece, applies pressure to the workpiece, and generates heat by supplying power to heat the workpiece, and protrudes on the opposite side from the connecting part 4 (leg 7). This heating part 3 is also in the shape of a two-tiered round bar that is thinner than the outer diameter of the chip substrate 2.

[0044] [Mating space] 3(a) to 3(c), the insides of the four legs 7 form a fitting space 8, and the lower ends of the fitting space 8 form lower openings that open toward the lower ends 7a of the legs 7. The ceiling surface 8a of this fitting space 8 is also curved in an arc to match the shape of the outer peripheral surface 14a of the protrusion 14 (FIGS. 6(b) and 6(d) and 9(b)) at one axial end of the shank 5, so that when it is placed over the protrusion 14, it comes into surface contact with the outer peripheral surface 14a of the protrusion 14.

[0045] [Sensor mounting part] A sensor mounting portion 3b protrudes downward from the center of the ceiling surface 8a of the fitting space portion 8 (FIGS. 6(b) and 9(a)). The outer peripheral surface of the sensor mounting portion 3b opens to the outer peripheral surface of the heating portion 3 as shown in FIG. 6(d).

[0046] [Temperature sensor] A lead wire L (FIG. 6(b)) extending from the temperature sensor S attached to the sensor attachment portion 3b is extended to the outside of the heating portion 3 from the outer peripheral surface of the sensor attachment portion 3b.

[0047] (Another embodiment of the electrode tip) The electrode tip 1 of any of the first to third embodiments can have a shape other than that shown in the drawings, such as a square rod, a thick block, or other shapes. In this case, the tip substrate 2 can be a square rod, a plate, or other shape, and the heating part 3 can also be a square rod or other shape. The shapes, lengths, and other dimensions of the tip substrate 2 and the heating part 3 can also be determined according to the application.

[0048] The number and shape of the legs 7, the shape and depth of the fitting space 8, the shape of the ceiling surface 8a, the shape and size of the heating portion 3, etc. can be designed arbitrarily in relation to the material of the chip substrate 2, the material of the workpiece to be welded, and other factors.

[0049] (Embodiment 1 of the resistance welding electrode) A first embodiment of a resistance welding electrode 10 of the present invention has an electrode tip 1 attached to a shank 5, as shown in FIGS. 4(a) to 4(d).

[0050] [Electrode tip] The electrode tip 1 can be of various structures, shapes, and sizes, but the electrode tip 1 of the resistance welding electrode 10 of FIGS. 4(a) to 4(d) is the electrode tip 1 of FIGS. 1(a) to 1(c).

[0051] [shank] Shanks 5 of various structures, shapes, and sizes can be used, but the shank 5 of the resistance welding electrode 10 of Figures 4(a) to (d) has a round bar-shaped shank base material 11 with a tip mounting portion (mounting hole) 13 (Figures 4(b) to (d), Figure 7(b)) for mounting the electrode tip 1 opened at one axial end face (mounting end face) 12. Four tip mounting portions 13 are provided at equal intervals around the circumferential direction of the shank base material 11. Each tip mounting portion 13 has the same shape and length as the leg 7 of the electrode tip 1 so that the leg 7 can be inserted therein.

[0052] [Shank convexity] As shown in FIG. 7(b), a convex portion 14 protruding in an arc shape is provided at the center of one axial end face (mounting end face) 12 of the shank 5, and the ceiling surface 8a of the fitting space 8 of the electrode tip 1 (FIGS. 1(a) and 7(a)) is placed on top of the convex portion 14, with the inner peripheral surface of the ceiling surface 8a being in surface contact with the outer peripheral surface 14a of the convex portion 14. The upper surface of the convex portion 14 may be flat or have other shapes. This also applies to the following embodiments. In such a case, it is desirable that the ceiling surface 8a of the fitting space 8 of the electrode tip 1 (FIGS. 1(a) and 7(a)) also be shaped so as to be in surface contact with the ceiling surface 8a.

[0053] [Shank material] The material of the shank 5 can be copper, copper alloy, aluminum, or other materials, similar to general-purpose shanks. These materials have low electrical resistivity and generate almost no heat when current is applied. Furthermore, being metallic, they are less likely to break during welding. They do not react with oxygen or water in the atmosphere, or if they do, they react only on the very surface. They are easy to cast and machine to obtain the desired shank shape, and the material is inexpensive. This material is also used in the following embodiments.

[0054] [Shank and tip connection] The resistance welding electrode 10 of FIGS. 4(a) to (d) has four legs 7 (FIGS. 1(a) and 7(a)) of the electrode tip 1 attached by brazing or press-fitting to four hole-shaped tip attachment portions 13 (FIGS. 4(c) and 7(b)) of the shank 5. The outer peripheral surfaces of the four legs 7 are in surface contact with the inner peripheral surface of the hole-shaped tip attachment portion 13. Also, as shown in FIGS. 4(b) and 4(d), the ceiling surface 8a of the fitting space 8 of the electrode tip 1 covers and is in surface contact with the outer peripheral surface 14a of the protrusion 14 of the shank 5 (FIGS. 4(b) and 4(d)).

[0055] [Heating part protrusion dimensions] The protrusion dimension H (FIG. 4(b)) of the heating portion 3 of the electrode tip 1 attached to the shank 5 is the dimension from the attachment end surface 12 of the shank 5 to the heating surface (contact surface) 3a of the heating portion 3. This protrusion dimension H varies depending on the material of the workpiece, the heat generation temperature required for welding, the cooling time of the electrode, etc., but it is desirable to make it larger when the heat generation temperature at the joining point (welding point) of the workpieces is to be increased, and to make it smaller when the heat generation temperature is to be suppressed. This protrusion dimension H is the same in the embodiment of the resistance welding electrode 10 described below.

[0056] [Temperature sensor] A temperature sensor S is attached to the outer periphery of the heating part 3 of the electrode tip 1 as shown in Figures 4(a), (b), and (d) to detect the temperature of the electrode tip 1. The temperature sensor S is a thermocouple or other temperature sensor. L in Figures 4(a) and (d) is a lead wire drawn from the temperature sensor S.

[0057] (Embodiment 2 of the resistance welding electrode) The resistance welding electrode 10 of the second embodiment has an electrode tip 1 attached to a shank 5 as shown in Figures 5(a) to (d). Electrode tips 1 of various structures, shapes, and sizes can be used, but the electrode tip 1 in Figures 5(a) to (d) is the electrode tip 1 in Figures 2(a) to (c).

[0058] [shank] 5(a) to 5(d), the shank 5 has elongated, groove-like tip mounting portions 15 for mounting the electrode tip 1 formed on the outer peripheral surface of the mounting end face 12 side of the round bar-shaped shank base material 11. There are four tip mounting portions 15, the same number as the number of legs 7 of the electrode tip 1. The outer periphery of each tip mounting portion 15 opens into the outer peripheral surface of the round bar-shaped shank 5. The tip mounting portions 15 have the same shape and length as the legs 7 of the electrode tip 1 so that the legs 7 of the electrode tip 1 can be brazed or press-fitted.

[0059] [Shank convexity] The central portion of the mounting end face 12 of the shank 5 is formed as a convex portion 14 that protrudes in an arc shape as shown in Figure 8(b), and the fitting space portion 8 of the electrode tip 1 (Figure 8(a)) is placed on top of the convex portion 14 so that the inner surface of the fitting space portion 8 is in surface contact with the outer surface 14a of the convex portion 14 as shown in Figures 5(b) and (d).

[0060] [Space] As shown in FIG. 8(b), a space 16 is provided in the center of the protrusion 14, recessed toward the inside in the axial direction of the shank 5 (downward in FIG. 8(b)).

[0061] [Shank and tip connection] The resistance welding electrode 10 of Figures 5(a) to (d) is attached by fitting the four legs 7 (Figures 2(a) and 8(a)) of the electrode tip 1 into the four groove-shaped tip attachment portions 15 (Figures 5(c) and 8(b)) of the shank 5 and brazing or press-fitting them. In this case, as shown in Figure 5(c), the outer peripheral surface of the tip attachment portion 15 is open to the outer peripheral surface of the shank base material 11, so that the outer peripheral surfaces of the four legs 7 attached to the tip attachment portion 15 are exposed (revealed) to the outer peripheral surface of the shank base material 11.

[0062] [Temperature sensor] A temperature sensor S is attached to the sensor attachment portion 3b (Figs. 5(b)(d)) provided on the outer circumferential surface of the heating portion 3 of the electrode tip 1 so as to detect the temperature of the electrode tip 1. This temperature sensor S is also a thermocouple or other temperature sensor. L in Fig. 5(b) is a lead wire drawn from the temperature sensor S, which is drawn into the space 16 of the shank 5.

[0063] (Embodiment 3 of the resistance welding electrode) The resistance welding electrode 10 of the third embodiment has an electrode tip 1 attached to a shank 5 as shown in Figures 6(a) to 6(d). Electrode tips 1 of various structures, shapes, and sizes can be used, but the electrode tip 1 in Figures 6(a) to 6(d) is the electrode tip 1 in Figures 3(a) to 3(c).

[0064] [shank] 6(a) to 6(d), the shank 5 has elongated hole-like tip mounting portions 13 for mounting the electrode tip 1 opened on the mounting end face 12 side of the round bar-shaped shank base material 11. Four tip mounting portions 13 are provided at equal intervals around the circumferential direction of the shank base material 11. Each tip mounting portion 13 has the same shape and length as the leg 7 of the electrode tip 1 so that the leg 7 can be inserted therein.

[0065] [Shank convexity] The central portion of the mounting end face 12 of the shank 5 is formed as a convex portion 14 that protrudes in an arc shape as shown in Figure 9(b), and the fitting space portion 8 of the electrode tip 1 (Figure 9(a)) fits over the convex portion 14 so that the inner surface of the fitting space portion 8 is in surface contact with the outer surface 14a of the convex portion 14 as shown in Figures 6(b) and (d).

[0066] [Space] As shown in FIG. 9(b), a space 16 is provided in the center of the protrusion 14, recessed toward the inside in the axial direction of the shank 5 (downward in FIG. 9(b)).

[0067] [Shank and tip connection] The resistance welding electrode 10 of FIGS. 6(a) to 6(d) has four legs 7 (FIGS. 2(a) and 9(a)) of the electrode tip 1 attached by brazing or press-fitting into four hole-shaped tip attachment portions 13 (FIGS. 6(c) and 9(b)) of the shank 5. The outer peripheral surfaces of the four legs 7 are in surface contact with the inner peripheral surface of the hole-shaped tip attachment portion 13. Also, as shown in FIGS. 6(b) and 6(c), the ceiling surface 8a of the fitting space 8 of the electrode tip 1 covers the protrusion 14 of the shank 5 and is in surface contact with the outer peripheral surface 14a of the protrusion 14.

[0068] [Temperature sensor] In this embodiment, a temperature sensor S is attached to the sensor attachment portion 3b (FIGS. 6(b) and (d)) provided on the outer peripheral surface of the heating portion 3 of the electrode tip 1 so as to detect the temperature of the electrode tip 1. This temperature sensor S is also a thermocouple or other temperature sensor. L in FIG. 6(b) is a lead wire drawn from the temperature sensor S, which is drawn into the space 16 of the shank 5.

[0069] [Attaching the electrode tip to the shank] The electrode tip 1 can be attached to the shank 5 by any method other than brazing or press-fitting, such as NDB method or friction welding.

[0070] In Figures 4 to 6, the electrode tip 1 is attached to one axial end of the shank 5, but it can also be attached to both ends of the shank 5. The electrode tips 1 attached to both ends may be the same or different. The protrusion dimension H may also be the same or different.

[0071] The resistance welding electrode 10 of the present invention can also be used for spot welding, which welds only a relatively narrow circular area, seam welding, which continuously welds a seam, projection welding, which involves forming a protrusion on a part of the material to be welded in advance and passing current through that part to weld, butt resistance welding, thermal crimp welding, also known as fusing welding, and other resistance welding methods. [Industrial Applicability]

[0072] The above-described embodiments of the electrode tip and the resistance welding electrode are merely examples of the present invention, and structures, shapes, sizes, materials, etc. other than those of the above-described embodiments may be used as long as the object of the present invention can be achieved. [Explanation of symbols]

[0073] 1 Electrode Tip 2 Chip substrate 3 Heating section 3a heating surface 3b Sensor mounting part 3c (Sensor mounting opening) 4 Connecting part 5 shank 7 legs 7a (Leg) Lower End 8. Fitting space 8a (Fitting space) ceiling surface 10 Resistance welding electrodes 11 Shank base material 12 Mounting end face 13 (Hole-shaped) tip attachment part 14 Convex part 14a (Convex) outer surface 15 (Grooved) Tip Mounting Portion 16 Space section A. Tip electrode (electrode tip) B Shank (base) E-electrode H protrusion dimension L lead wire S Temperature Sensor W: Material to be welded (work)

Claims

1. It has a connecting part that is attached to the shank and a heating part that heats the workpiece. The connecting part is branched into several legs, There are fitting spaces inside several legs, The tip side of the fitting space is open so that it can be placed over the shank. Electrode tip for resistance welding characterized by:

2. 2. The resistance welding electrode tip according to claim 1, The several legs are branched at intervals in the circumferential direction of the chip substrate. Electrode tip for resistance welding characterized by:

3. 2. The resistance welding electrode tip according to claim 1, The several legs can be attached to the shank by inserting them into two or more tip attachment portions opened in the shank, or by fitting them into two or more tip attachment portions formed in outer openings on the outer peripheral surface of the shank. Electrode tip for resistance welding characterized by:

4. 2. The resistance welding electrode tip according to claim 1, There is a sensor mounting area on the outer periphery of the heating section. A temperature sensor is attached to the sensor mounting section. Electrode tip for resistance welding characterized by:

5. 2. The resistance welding electrode tip according to claim 1, There is a sensor mounting part inside the heating part, A temperature sensor is attached to the sensor mounting section. Electrode tip for resistance welding characterized by:

6. 2. The resistance welding electrode tip according to claim 1, There is a sensor mounting part inside the heating part, A temperature sensor is attached to the sensor mounting section. The lead wire of the temperature sensor is drawn out from the heating part through an opening on the outer peripheral surface of the heating part. Electrode tip for resistance welding characterized by:

7. 2. The resistance welding electrode tip according to claim 1, At least the surface of the heating part is covered with a carbonized film. Electrode tip for resistance welding characterized by:

8. A resistance welding electrode having an electrode tip attached to a shank, The electrode tip is an electrode tip for resistance welding according to any one of claims 1 to 7, Several legs of the electrode tip are attached to the shank either integrally or detachably, and the heating portion of the electrode tip protrudes outside the shank. A resistance welding electrode characterized by:

9. 9. The resistance welding electrode according to claim 8, Several legs of the electrode tip are inserted into several hole-like tip mounting portions that are elongated and open in the axial direction of the shank, and are connected integrally or detachably to the shank. A resistance welding electrode characterized by:

10. 9. The resistance welding electrode according to claim 8, Several legs of the electrode tip are fitted into several groove-like tip mounting portions that are elongated and open in the axial direction of the shank on the outer periphery of the shank, and are integrally or detachably connected to the shank. A resistance welding electrode characterized by:

11. 9. The resistance welding electrode according to claim 8, The electrode tip has several legs inserted into several hole-like tip mounting portions that are elongated and open in the axial direction of the shank, and the fitting space portions are fitted over protrusions that protrude from the mounting end surface of the shank, and the electrode tip is integrally or detachably connected to the shank. A resistance welding electrode characterized by:

12. 9. The resistance welding electrode according to claim 8, The electrode tip has several legs fitted into several groove-shaped tip mounting portions formed elongated in the axial direction of the shank, and the fitting spaces are fitted over protrusions protruding from the mounting end surface of the shank, and the electrode tip is integrally or detachably connected to the shank. A resistance welding electrode characterized by:

13. 9. The resistance welding electrode according to claim 8, The temperature sensor is attached to the outer peripheral surface of the electrode tip attached to the shank or to a sensor attachment portion formed on the electrode tip. A resistance welding electrode characterized by:

14. 9. The resistance welding electrode according to claim 8, The temperature sensor is attached to a sensor attachment portion of the electrode tip attached to the shank, and a lead wire of the temperature sensor is drawn into a space formed in the shank. A resistance welding electrode characterized by:

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