Resistor component, method for manufacturing a resistor component, and resistor

Abstract

To provide a member for a resistor, which is superior in bendability of a junction, and which enables the suppression of production of burr from the surface of the junction and the reduction of a rate of a resistance change to a temperature change, a production method thereof, and a resistor.SOLUTION: A member for a resistor comprises a first metal member 10 and a second metal member 20 which are joined to each other through a junction 30. The first metal member contains Cu of 99.96 mass% or more. The second metal member contains Cu of 83.00 mass% or more and 94.00 mass% or less. In a cross section perpendicular to a welding line 2, a junction width ratio (w1 / w) is 1.70 or more and 2.30 or less, and a junction width ratio (w2 / w) is 0.60 or more and 1.15 or less, where w1 is a first junction width of the junction in a first surface 31 of the junction, w2 is a second junction width of the junction in a second surface 32 of the junction opposed to the first surface, and w is a thickness-intermediary portion junction width of the junction in a thickness-intermediary portion 33 located between the first surface and the second surface.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a member for a resistor, a method for manufacturing the member for a resistor, and a resistor.

Background Art

[0002] In recent years, as the requirements for materials have been increasing year by year, joining of metals having contradictory properties has been demanded. For example, in the field of heat exchangers, materials with high thermal conductivity such as copper, copper alloys, aluminum, and aluminum alloys are combined with materials with high heat resistance such as stainless steel and heat-resistant steel. In other fields, there are high demands for joining various metal plates, such as combining materials with a high specific gravity such as copper and copper alloys with materials with a low specific gravity such as aluminum and aluminum alloys.

[0003] In addition, there are also many examples that have already been in actual use. A bimetal has materials with different coefficients of thermal expansion joined together. In a shunt resistor, a member for a resistor in which a low-resistance material (for example, pure copper) and a high-resistance material (for example, a resistance alloy) are joined is incorporated.

[0004] There are various methods for joining materials having contradictory properties, such as fusion joining, solid-phase joining, brazing, adhesion, and mechanical joining. Among them, the joining method by fusion joining has been used for a long time and is practical and has many achievements. Examples of fusion joining include arc welding represented by TIG welding, MIG / MAG welding, and plasma welding, resistance welding represented by spot welding, seam welding, projection welding, and flash butt welding, and further high-energy beam welding represented by laser beam welding and electron beam welding.

[0005] Among these, laser beam welding is a welding method that uses laser light as a heat source, focusing it primarily on metal and locally melting and solidifying the metal. Laser beam welding can weld in a short time by utilizing its high energy density, and in recent years, the functionality of laser welding light sources has been improving, such as in fiber laser welding. Because laser light is a single-wavelength light with no phase difference, it can be focused into an extremely small point by the lens of the optical system to obtain high-density energy. Therefore, it has the advantage of allowing for a very narrow joining width.

[0006] However, in fiber laser welding, due to the characteristics of the laser, even slight changes in joining conditions can reduce the joint strength. This makes the joint more susceptible to cracking when bending stress is applied. Such problems associated with bending are issues that need to be addressed for resistor components.

[0007] Furthermore, Patent Document 1 describes a shunt resistor in which a portion of the base material is cut and a portion of the cut material is bent, with the aim of suppressing heat generation. Furthermore, Patent Document 2 describes a shunt resistor in which the electrodes are bent, with the aim of stabilizing the resistance value. Furthermore, Patent Document 3 describes a shunt resistor in which a string pattern is formed on the surface of the resistive alloy material by laser processing, with the aim of reliably informing the user of the set resistance value.

[0008] Here, the bendability of the joint surface is an important indicator for evaluating welding quality, and its evaluation method is specified and standardized in JIS Z 3122 "Bending Test Method for Butt Welded Joints". On the other hand, Patent Documents 1 to 3 do not mention any technology or studies for improving the bendability of resistor components that constitute shunt resistors.

[0009] Furthermore, in recent years, with the downsizing of electronic devices, the shape of shunt resistors has become more complex, and the demand for shunt resistors with bent components has increased. Moreover, the required standards for the accuracy of electrical resistance values ​​and long-term performance reliability are rising year by year. Cracks on the joint surface not only affect the electrical resistance value, but vibration and shock can cause these cracks to spread, potentially leading to an abnormal increase in electrical resistance or loss of function. Therefore, it is required that there be no cracks on the joint surface. In addition, resistor components are required to suppress burrs generated on the joint surface and to reduce the rate of change in resistance value with respect to temperature changes. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] Japanese Patent Publication No. 2019-91824 [Patent Document 2] Japanese Patent Publication No. 2018-18960 [Patent Document 3] International Publication No. 2016 / 175016 [Overview of the Initiative] [Problems that the invention aims to solve]

[0011] The object of this disclosure is to provide a resistor member that has excellent flexibility at the joint, suppresses the generation of burrs from the joint surface, and reduces the rate of change of electrical resistivity with respect to temperature changes, a method for manufacturing a resistor member, and a resistor. [Means for solving the problem]

[0012] [1] A resistor member comprising a first metal member and a second metal member joined via a joint, wherein the first metal member contains 99.96% by mass or more of Cu, and the second metal member contains 83.00% by mass or more and 94.00% by mass or less of Cu, and in a cross section perpendicular to the weld line, if the first joint width of the joint on the first surface of the joint is w1, the second joint width of the joint on the second surface of the joint facing the first surface is w2, and the intermediate thickness joint width of the joint in the intermediate thickness portion located between the first surface and the second surface is w, then the joint width ratio (w1 / w) is 1.70 or more and 2.30 or less, and the joint width ratio (w2 / w) is 0.60 or more and 1.15 or less. [2] The resistor member according to [1] above, wherein the resistor member has a bent portion, the bent portion is bent with the first surface of the joint portion as the outer surface of the bent portion, and the center of the bend is within 5.0 mm from the middle of the joint width of the joint portion in the cross section. [3] The resistor member according to [1] or [2] above, wherein the resistor member has a bent portion, and the bending radius on the inner surface side of the bent portion is 0.5 times or more the thickness of the first metal member. [4] The resistor component according to any one of [1] to [3] above, wherein the second metal component is a copper alloy having an alloy composition containing 10.00% by mass or more and 13.00% by mass or less of Mn, and 1.50% by mass or more and 3.00% by mass or less of Ni, with the remainder being Cu and unavoidable impurities. [5] The resistor component according to any one of [1] to [3] above, wherein the second metal component is a copper alloy having an alloy composition containing 6.00% by mass or more and 8.00% by mass or less of Mn, and 1.00% by mass or more and 4.00% by mass or less of Sn, with the remainder being Cu and unavoidable impurities. [6] A method for manufacturing a resistor component according to any one of [1] to [5] above, comprising a joining step of joining a first metal component and a second metal component with a fiber laser. [7] A resistor using any one of the resistor components described in [1] to [5] above. [Effects of the Invention]

[0013] According to the present disclosure, it is possible to provide a member for a resistor that has excellent bendability at a joint, suppresses the generation of burrs from the joint surface, and reduces the rate of change in electrical resistivity with respect to temperature changes, a method for manufacturing the member for a resistor, and a resistor.

Brief Description of the Drawings

[0014] [Figure 1] FIG. 1 is a perspective view showing an example of a member for a resistor according to an embodiment. [Figure 2] FIG. 2 is an enlarged cross-sectional view showing an example of a member for a resistor according to an embodiment. [Figure 3] FIG. 3 is a cross-sectional view showing another example of a member for a resistor according to an embodiment. [Figure 4] FIG. 4 shows the result of observing a cross-section perpendicular to the weld line of the member for a resistor of Example 1 with a microscope.

Modes for Carrying Out the Invention

[0015] Hereinafter, embodiments will be described in detail.

[0016] As a result of intensive research, the inventors of the present invention utilized fiber laser welding (fiber laser welding), which has advantages such as being able to be joined in the atmosphere without the need for a vacuum device and using a small amount of inert gas among high-energy beam weldings, and by controlling the cross-sectional shape of the joint to a predetermined shape, it was found that a member for a resistor with excellent bendability at the joint, suppressing the generation of burrs from the joint surface, and reducing the rate of change in electrical resistivity with respect to temperature changes can be obtained, and based on such findings, the present disclosure has been completed.

[0017] The resistor member of the embodiment is a resistor member in which a first metal member and a second metal member are joined via a joint portion. The first metal member contains 99.96 mass% or more of Cu, and the second metal member contains 83.00 mass% or more and 94.00 mass% or less of Cu. In a cross-section perpendicular to the weld line, the first joint width of the joint portion on the first surface of the joint portion is w1, the second joint width of the joint portion on the second surface of the joint portion facing the first surface is w2, and the thickness intermediate joint width of the joint portion in the thickness intermediate portion located between the first surface and the second surface is w. Then, the joint width ratio (w1 / w) is 1.70 or more and 2.30 or less, and the joint width ratio (w2 / w) is 0.60 or more and 1.15 or less.

[0018] FIG. 1 is a perspective view showing an example of the resistor member of the embodiment. Further, FIG. 2 is an enlarged cross-sectional view showing an example of the resistor member of the embodiment. FIG. 2 shows a cross-section perpendicular to the weld line 2 provided in the resistor member 1 shown in FIG. 1.

[0019] As shown in FIGS. 1 to 2, the resistor member 1 is formed by joining a first metal member 10 and a second metal member 20 via a joint portion 30.

[0020] The first metal member 10 constituting the resistor member 1 contains 99.96 mass% or more of Cu. Further, the second metal member 20 contains 83.00 mass% or more and 94.00 mass% or less of Cu. When the first metal member 10 and the second metal member 20 are the above components, respectively, it is possible to suppress the deviation of current detection generated during use and reduce the temperature resistance coefficient indicating the change in volume resistance value with respect to temperature change.

[0021] Moreover, the resistor member 1 composed of the first metal member 10 and the second metal member 20 having the above composition is suitable as a shunt resistor member. In a shunt resistor composed of a copper-based material, generally, a copper alloy, so-called resistance alloy, in which the electrical resistance value and the resistance temperature coefficient are adjusted, is used for the resistor body, and the resistor body is joined to pure copper. When the resistor member 1 is used as a shunt resistor member, the second metal member 20 functions as a resistor body and is joined to the first metal member 10 which is pure copper such as oxygen-free copper.

[0022] In particular, in order to suitably use the resistor member 1 as a shunt resistor member, it is preferable that the first metal member 10 has the above components, and the second metal member 20 is a copper alloy having an alloy composition containing 10.00% by mass or more and 13.00% by mass or less of Mn, and 1.50% by mass or more and 3.00% by mass or less of Ni, with the remainder being Cu and unavoidable impurities.

[0023] If the Cu content of the first metal component 10 is within the above range, it functions sufficiently as a shunt resistor and can adequately suppress current detection errors that occur during use. Furthermore, if the second metal component 20 is a copper alloy having the above alloy composition, the temperature resistance coefficient can be sufficiently reduced, making it suitable for use as a shunt resistor.

[0024] In addition to the above, in order for the resistor member 1 to be suitably used as a shunt resistor member, it is preferable that the first metal member 10 has the above components, and the second metal member 20 is a copper alloy having an alloy composition containing 6.00% by mass or more and 8.00% by mass or less of Mn, and 1.00% by mass or more and 4.00% by mass or less of Sn, with the remainder being Cu and unavoidable impurities.

[0025] If the Cu content of the first metal component 10 is within the above range, it functions sufficiently as a shunt resistor and can adequately suppress current detection errors that occur during use. Furthermore, if the second metal component 20 is a copper alloy having the above alloy composition, the temperature resistance coefficient can be sufficiently reduced, making it suitable for use as a shunt resistor.

[0026] Furthermore, if the volume resistivity of the first metal member 10 is 1.76 μΩ·cm or less, and the volume resistivity of the second metal member 20 is between 27.50 μΩ·cm and 47.00 μΩ·cm, the resistor member 1 can be suitably used as a shunt resistor member. If the volume resistivity of the first metal member 10 is within the above range, abnormal heat generation due to the applied current can be suppressed. Also, if the volume resistivity of the second metal member 20 is within the above range, it satisfies one of the existing design standards for shunt resistors, thus offering high versatility.

[0027] Furthermore, as shown in Figure 2, in a cross section perpendicular to the weld line 2, if the first joint width of the joint 30 on the first surface 31 of the joint 30 is denoted as w1, the second joint width of the joint 30 on the second surface 32 of the joint 30 is denoted as w2, and the intermediate thickness joint width of the joint 30 at the intermediate thickness portion 33 located between the first surface 31 and the second surface 32 is denoted as w, then the joint width ratio (w1 / w) is 1.70 or more and 2.30 or less, and the joint width ratio (w2 / w) is 0.60 or more and 1.15 or less.

[0028] As shown in Figure 2, the first surface 31 of the joint 30 is a virtual surface formed by a straight line connecting the first surface side (upper side in the plane of the paper) and second metal member side (right side in the plane of the paper) end of the first metal member 10 and the first surface side (left side in the plane of the paper) end of the second metal member 20. The second surface 32 of the joint 30 is a virtual surface formed by a straight line connecting the second surface side (lower side in the plane of the paper) and second metal member side end of the first metal member 10 and the second surface side and first metal member side end of the second metal member 20. The first surface 31 and the second surface 32 face each other. The thickness intermediate portion 33 of the joint 30 is the line bisector of the distance between the first surface 31 and the second surface 32, and is a line that divides the thickness of the joint 30 equally.

[0029] Furthermore, if the thickness t10 of the first metal member 10 and the thickness t20 of the second metal member 20 are different, the first surface 31 and the second surface 32 are defined based on the metal member with the thinner thickness.

[0030] If the thickness t10 of the first metal member 10 is thinner than that of the second metal member 20, the following occurs: The first surface 31 of the joint 30 is a linear virtual surface that extends along the first surface side of the first metal member 10, from the first surface side and second metal member side end of the first metal member 10 toward the second metal member 20. The second surface 32 of the joint 30 is a linear virtual surface that extends along the second surface side of the first metal member 10, from the second surface side and second metal member side end of the first metal member 10 toward the second metal member 20.

[0031] If the thickness t20 of the second metal member 20 is thinner than that of the first metal member 10, the following occurs: The first surface 31 of the joint 30 is a linear virtual surface that extends along the first surface side of the second metal member 20, from the first surface side and first metal member side end of the second metal member 20 toward the first metal member 10. The second surface 32 of the joint 30 is a linear virtual surface that extends along the second surface side of the second metal member 20, from the second surface side and first metal member side end of the second metal member 20 toward the first metal member 10.

[0032] In applications where resistor components are bent, the bending stress is concentrated on the outer surface of the bent portion. Therefore, by intentionally widening the joint width on the surface corresponding to the outer side of the bend and softening that portion, the occurrence of cracks on the joint surface can be suppressed. From this perspective, it is conceivable to increase the laser power density (ratio of laser output value to laser area) in fiber laser bonding to about 1.5 to 2.5 times the minimum value required for material bonding, thereby widening the joint width of the joint from the first surface to the second surface. However, in this case, there is a greater amount of material loss at the second surface 32 of the joint 30, which is the beam penetration surface, and welding burrs are likely to occur from the joint surface. In addition, the initial cost of introducing a high-power processing machine increases, and an increase in running costs due to high-power, low-speed bonding is unavoidable. On the other hand, if the overall joint width is narrowed to reduce welding burrs, the softening range in the bent portion is insufficient, and cracks are likely to occur when bending. Therefore, in order to achieve both improved bendability and suppression of welding burr generation, it is efficient to widen the joint width on the outer surface of the bent section, while keeping the joint width in other areas to the minimum width necessary for joining.

[0033] In light of the above, after careful consideration, we have found that when the joint width w in the middle of the thickness is set to 1, the value of the first joint width w1, which is the joint width of the surface on the outside of the bent portion, i.e., the joint width ratio (w1 / w), is 1.70 or higher, it is possible to achieve both improved bendability of the joint and suppression of welding burr generation. Furthermore, even if the joint width ratio (w1 / w) is 2.30 or higher, this effect saturates, leading to an increase in the energy required to join the first and second metal members, which is not economically desirable.

[0034] Furthermore, when the joint width w in the middle of the thickness is set to 1, the value of the second joint width w2, which is the joint width of the surface on the inside of the bent portion, i.e., the joint width ratio (w2 / w), is 0.60 or higher, which can suppress the risk of joint defects such as unjointed areas. Also, if the joint width ratio (w2 / w) is 1.15 or lower, the generation of welding burrs can be suppressed.

[0035] Furthermore, in resistor components having a joint cross-section where the joint width ratio (w1 / w) and joint width ratio (w2 / w) are within the above range, the rate of change of electrical resistivity with respect to temperature changes can be reduced. Specifically, the electrical resistivity of a resistor component is measured at room temperature (20°C), but when the electrical resistivity is measured while changing the measurement temperature from -40°C to 80°C, the maximum rate of change of electrical resistivity measured in this temperature range is 5.0% or less, with the electrical resistivity at 20°C as the reference.

[0036] The first metal component has lower electrical resistivity and greater temperature dependence compared to the second metal component. On the other hand, the second metal component has higher electrical resistivity and less temperature dependence. However, if the resistor component is a shunt resistor component, the volume ratio of the first metal component is large, resulting in greater temperature dependence of the electrical resistivity. Nevertheless, if the junction width ratio (w1 / w) and junction width ratio (w2 / w) are within the above range, the change in the electrical resistivity of the resistor component can be kept below 5.0%.

[0037] Furthermore, the ratio (t20 / t10) of the thickness t20 of the second metal member 20 to the thickness t10 of the first metal member 10 is preferably 0.5 or more and 2.0 or less. If the ratio (t20 / t10) is 0.5 or more, the detection sensitivity can be increased when detecting large currents. Also, if the ratio (t20 / t10) is 2.0 or less, the detection sensitivity can be increased when detecting small currents.

[0038] When the thickness t10 of the first metal member 10 and the thickness t20 of the second metal member 20 are different, it is preferable that the surfaces of the first metal member 10 and the second metal member 20 be aligned so as not to create irregularities. In particular, it is more preferable that the surfaces of the first metal member 10 and the second metal member 20 be aligned on the first surface side, which is the side on which the laser light is incident.

[0039] Furthermore, if the change in electrical resistivity due to the operating temperature of the resistor component is 5.0% or less, the measurement error when using the resistor component as a shunt resistor component is acceptable. According to the appendix of JIS C 2522, the strictest tolerance for conductor resistance is 5.0%, and any change below this is acceptable for practical use. Also, if the temperature range is within the minimum and maximum temperature range listed in Table 4 of JIS C 2522, it can be judged that there is no problem for practical use. Moreover, by limiting the component range of the second metal component, the change in electrical resistivity can be reduced to 4.0% or less.

[0040] Figure 3 is a cross-sectional view showing another example of a resistor component of the embodiment. Like Figure 2, Figure 3 shows a cross-section perpendicular to the weld line 2.

[0041] As shown in Figure 3, the resistor member 1a has a bent portion 40, and it is preferable that the bent portion 40 is bent with the first surface 31 of the joint portion 30 as the outer surface of the bent portion 40, and with the bending center position being within 5.0 mm from the middle 34 of the joint width of the joint portion 30 in cross-section.

[0042] As shown in Figure 2, the intermediate joint width 34 is the bisector of the width dimension of the joint 30 in a cross section perpendicular to the weld line 2. Figure 3 shows an example where the joint width intermediate 34 is used as the bending center position.

[0043] When the outer surface of the bent portion 40 is the first surface 31 of the joint portion 30, the joint portion 30 has excellent bendability and the generation of burrs from the surface of the joint portion 30 can be suppressed.

[0044] Furthermore, if the joint 30 is bent with the bending center position being within 5.0 mm of the middle of the joint width 34, the following effect occurs. That is, when bending is performed on the first metal member 10 and the second metal member 20, the electrical resistance value of each member changes. On the other hand, since the joint 30 is a mixture of the first metal member 10 and the second metal member 20, the electrical resistance values ​​of the joint 30 differ from those of each member. By performing the bending process with the aforementioned portion as the bending center position, the area where the electrical resistance value changes can be minimized. For example, if one second metal member is joined between two first metal members 10, there are two joint locations for these members. If bending is performed on the aforementioned portion of the joint 30 and on the first metal member, there will be two locations where the electrical resistance value changes. On the other hand, if bending is performed only on the first metal member, there will be four locations where the electrical resistance value changes. In this way, the risk and impact of changes in electrical resistance value can be reduced.

[0045] Furthermore, it is preferable that the bending radius on the inner side of the bent portion 40 is 0.5 times or more the thickness t10 of the first metal member 10. If the bending radius is within the above range, the risk of crack formation in the joint portion 30 can be reduced.

[0046] As described above, the resistor members 1 and 1a have excellent flexibility at the joint 30, suppress the generation of burrs from the joint surface, and reduce the rate of change in resistance due to temperature changes. Therefore, the resistor members 1 and 1a can be suitably used in resistors. Among these, the resistor members 1 and 1a are preferably used in shunt resistors.

[0047] Next, a description of the manufacturing method for the resistor component 1 will be provided.

[0048] The manufacturing method for the resistor component 1 includes a joining step of joining a first metal component 10 and a second metal component 20 using a fiber laser. In the manufacturing method for the resistor component 1, fiber laser welding is used, which is a type of high-energy beam welding that does not require a vacuum device and can be performed in the atmosphere, uses a small amount of inert gas, has advantages such as less contamination of the joint with impurities, easy control of electrical resistance, and a narrow joint width that can suppress welding deformation.

[0049] Fiber laser welding is a method of joining metal components by using a laser beam as a heat source, focusing the laser beam, and irradiating the metal components with it, causing localized melting and solidification of the metal components. Fiber laser welding can join metal components in a short time by utilizing a laser beam with high energy density.

[0050] In the joining process, a laser beam is irradiated along the abutting surfaces of the first metal member 10 and the second metal member 20 that are joined together. At this time, the focusing position of the laser beam is intentionally shifted from the surface of the abutting surfaces, i.e., defocused, or the beam shape of the laser beam is controlled to separately create high-energy and low-energy focal points, thereby joining the first metal member 10 and the second metal member 20 to manufacture the resistor member 1.

[0051] In the above description, an example of melt-joining the first metal member 10 and the second metal member 20 using a fiber laser was explained, but the first metal member 10 and the second metal member 20 may also be melt-joined using a high-energy beam such as an electron beam.

[0052] According to the embodiments described above, by utilizing fiber laser bonding and controlling the cross-sectional shape of the joint to a predetermined shape, it is possible to obtain a resistor member that has excellent flexibility at the joint, suppresses the generation of burrs from the joint, and reduces the rate of change of electrical resistivity with respect to temperature changes.

[0053] Although embodiments have been described above, the present invention is not limited to the embodiments described above, and includes all aspects included in the concepts and claims of this disclosure, and can be modified in various ways within the scope of this disclosure. [Examples]

[0054] Examples and comparative examples will be described next, but this disclosure is not limited to these examples.

[0055] Plate-shaped first and second metal members (both manufactured by Furukawa Electric Co., Ltd.) having the components and thicknesses shown in Tables 1 and 2 were prepared. In addition, a fiber laser processing machine was used, consisting of an oscillator (FEC6000M (multimode light source, maximum 6kW compatible), manufactured by Furukawa Electric Co., Ltd.) and an optical head (FKR-S-600049, manufactured by Furukawa Electric Co., Ltd.).

[0056] Specifically, with the first and second metal members butted together, a fiber laser was irradiated onto them at the laser output and focus position shown in Tables 1 and 2 while the butted metal members were transported at the transport speeds shown in Tables 1 and 2. The focus position was selected from either defocus, where the focal point of the laser beam is shifted 1 to 2 mm upward from the surface of the butt joint (the boundary between the first and second metal members), or just focus, where the focal point of the laser beam is aligned with the surface of the butt joint. In addition, nitrogen gas (30 l / min) was blown onto the laser beam during irradiation with the fiber laser to prevent attenuation of the laser beam due to metal vapor. In this way, the first and second metal members were joined together to manufacture a resistor component.

[0057] [evaluation] The resistor components obtained in the above examples and comparative examples were evaluated as follows. The results are shown in Tables 1 and 2.

[0058] [1] Component analysis For the component analysis of resistor materials, copper was analyzed according to JIS H 1051 "Method for determining copper in copper and copper alloys", tin according to JIS H 1052 "Method for determining tin in copper and copper alloys", manganese according to JIS H 1055 "Method for determining manganese in copper and copper alloys", nickel according to JIS H 1056 "Method for determining nickel in copper and copper alloys", and copper alloys according to JIS H 1292 "X-ray fluorescence analysis method for copper alloys".

[0059] [2] Electrical resistivity of the first metal member and the second metal member Using the first and second metal components before joining, the electrical resistivity was measured a total of four times in accordance with the four-terminal method of JIS H 0505, with an applied current of 0.1A, and the direction of current application was changed each time. The average value of these measurements was taken as the electrical resistivity.

[0060] [3] Observation of the cross section perpendicular to the weld line The resistor components were cut perpendicular to the weld line using a metal cutting machine. After mechanically polishing the cut surfaces, the cross-section of the joint perpendicular to the weld line was observed under a microscope at 100x magnification, and each dimension was measured. This measurement was performed at three locations (N=3) for each resistor component, and the average of the three measurements was taken as the value for each dimension.

[0061] [4] Flexibility and presence or absence of burrs Test pieces measuring 25-50 mm in length and 10 mm in width were cut from the resistor component. The bending center was set at a point on the first metal component side, separated from the midpoint of the joint width of the joint by the bending positions shown in Tables 1-2. The pieces were then bent (V-bend) using a compression tester at a speed of 10 mm / min. During bending, the bending radius on the inner side of the bent portion was set to 0.5 times the thickness of the first metal material. The bendability was visually inspected at the welded area (joint) and ranked as follows. Rank A was considered acceptable for bendability. The presence or absence of burrs was also visually inspected at the welded area. The absence of burrs was considered acceptable.

[0062] A: There were no abnormalities. B: A crack has occurred. C: It broke.

[0063] [5] Rate of change of electrical resistivity with respect to temperature change A resistor component was obtained by joining a second metal component to both sides of the first metal component. Two voltage measurement terminals were fixed to the second metal component using spring clips, and terminals for current application were fixed to the outside of the voltage measurement terminals using the same type of spring clips. The distance between the voltage measurement terminals was set to 50 mm. Next, the resistor component was placed in an atmospheric constant temperature furnace, the temperature was measured using the furnace's thermocouple, and the voltage was continuously measured using the four-terminal method while applying a current of 0.1 A from the positive side to the negative side. Specifically, the constant temperature bath was cooled and maintained at -40°C for 5 minutes before the voltage measurement was performed. Then, the constant temperature bath was heated, and the voltage was continuously measured in 5°C increments up to 80°C. After the measurement, the maximum rate of change of the measured electrical resistivity was calculated using the electrical resistivity at 20°C as the reference. A rate of change of 5.0% or less was considered acceptable.

[0064] [Table 1]

[0065] [Table 2]

[0066] As an example, Figure 4 shows the results of observing a cross-section perpendicular to the weld line of the resistor component of Example 1 using a microscope. As shown in Table 1, in resistor components where the first and second metal components each have a predetermined composition and the joint width ratio (w1 / w) and joint width ratio (w2 / w) in the cross-section perpendicular to the weld line each satisfy a predetermined value, the bendability, presence or absence of burrs, and rate of change of electrical resistivity all passed the test. On the other hand, as shown in Table 2, in resistor components where at least one of the first and second metal components does not have a predetermined composition, and / or where at least one of the joint width ratio (w1 / w) and joint width ratio (w2 / w) in the cross-section perpendicular to the weld line does not satisfy a predetermined value, at least one of the bendability, presence or absence of burrs, and rate of change of electrical resistivity did not pass the test. [Explanation of Symbols]

[0067] 1, 1a Resistor components 2 Weld lines 10 First metal member 20 Second metal component 30 Joint 31 1st surface 32 Second surface 33. Middle part of the thickness 34 Intermediate joint width 40 Bending section 41 Outer surface of the bent portion 42 Inner surface of the bent section t10 Thickness of the first metal member t20 Thickness of the second metal member w thickness, intermediate joint width w1 1st joint width w2 Second joint width

Claims

1. A resistor member comprising a first metal member and a second metal member joined together via a joint, The first metal member contains 99.96% by mass or more of Cu, The second metal member contains Cu in an amount of 83.00% by mass or more and 94.00% by mass or less. In a cross-section perpendicular to the weld line, if the first joint width of the joint on the first surface of the joint is w1, the second joint width of the joint on the second surface of the joint facing the first surface is w2, and the intermediate thickness joint width of the joint located midway between the first and second surfaces is w, then the joint width ratio (w1 / w) is 1.70 or more and 2.30 or less, and the joint width ratio (w2 / w) is 0.60 or more and 1.15 or less. Resistor components.

2. The resistor member has a bent portion, The resistor member according to claim 1, wherein the bent portion is bent with the first surface of the joint portion as the outer surface of the bent portion, and the bending center position is within 5.0 mm from the middle of the joint width of the joint portion in the cross section.

3. The resistor member has a bent portion, The resistor member according to claim 1, wherein the bending radius on the inner surface side of the bent portion is 0.5 times or more the thickness of the first metal member.

4. The resistor member according to claim 1, wherein the second metal member is a copper alloy having an alloy composition containing 10.00% by mass or more and 13.00% by mass or less of Mn, and 1.50% by mass or more and 3.00% by mass or less of Ni, with the remainder being Cu and unavoidable impurities.

5. The resistor member according to claim 1, wherein the second metal member is a copper alloy having an alloy composition containing 6.00% by mass or more and 8.00% by mass or less of Mn, and 1.00% by mass or more and 4.00% by mass or less of Sn, with the remainder being Cu and unavoidable impurities.

6. A method for manufacturing a resistor component according to any one of claims 1 to 5, comprising a bonding step of bonding a first metal component and a second metal component with a fiber laser.

7. A resistor using the resistor component described in any one of claims 1 to 5.

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