Current sensor and relay module

Abstract

A current sensor (10) comprises: a flat-plate-shaped first metal body (11) having a first fastening portion (14); a flat-plate-shaped second metal body (12) having a second fastening portion (15); and a flat-plate-shaped resistor (13) to which the first metal body (11) and the second metal body (12) are joined and which has a higher resistance value than the first metal body (11) and the second metal body (12). A first joining surface (16), which is the interface at which the first metal body (11) and the resistor (13) are joined, and a second joining surface (17), which is the interface at which the second metal body (12) and the resistor (13) are joined, are positioned on different surfaces of the resistor (13). At least one of (1) and (2) is satisfied. (1) The first joining surface (16) is configured from at least one of a plate surface of the first metal body (11) and a plate surface of the resistor (13). (2) The second joining surface (17) is configured from at least one of a plate surface of the second metal body (12) and a plate surface of the resistor (13).

Description

Current sensor and relay module

[0001] The present disclosure relates to current sensors and the like.

[0002] The simplest structure of a shunt resistor, a type of current sensor, is two plate-shaped metal bodies (e.g., copper plates) joined via a plate-shaped resistive body. Such current sensors are widely used as general-purpose products. Because of their simple structure, these current sensors are easy to mass-produce, but they have the characteristic of being difficult to dissipate heat generated by resistance at the junction between the metal bodies and the resistive body when a current is passed through the current sensor. Recently, with the spread of electric vehicles and the like, there has been an increasing demand for current sensors with efficient heat dissipation. Therefore, there has been an increasing demand for current sensors in which the shape of the two metal bodies is modified to improve heat dissipation efficiency (see, for example, Patent Document 1).

[0003] International Publication No. 2016 / 186022

[0004] In order to configure the current sensor to have the characteristics desired by the customer (for example, heat dissipation efficiency), it is necessary to manufacture the current sensor by stamping or / and bending the metal body, stamping the resistor, and joining the metal body and the resistor. When processing the metal body and the resistor as described above, a step of shearing the metal body and the resistor is performed.

[0005] However, shearing the metal body and the resistor may cause burrs and sagging on the sheared surfaces between the metal body and the resistor, or the surface roughness of the sheared surfaces of the metal body and the resistor may become greater than the surface roughness of the surfaces before shearing. When such sheared surfaces are used to join the metal body and the resistor, it is likely that the resistor will shift or the dimensional accuracy of the current sensor will decrease, resulting in poor current measurement accuracy, and that joining defects will occur due to the generation of bubbles such as pits, piping, or blowholes on the joining surfaces, which may reduce the productivity of the current sensor.

[0006] A current sensor according to one embodiment of the present disclosure comprises a flat first metal body having a first fastening portion, a flat second metal body having a second fastening portion, and a flat resistor joined to the first metal body and the second metal body and having a higher resistance value than the first metal body and the second metal body, wherein a first joint surface which is the interface where the first metal body and the resistor are joined, and a second joint surface which is the interface where the second metal body and the resistor are joined are located on different sides of the resistor, and at least one of the following is satisfied: (1) the first joint surface is formed by at least one of the plate surfaces of the first metal body and the plate surface of the resistor, and (2) the second joint surface is formed by at least one of the plate surfaces of the second metal body and the plate surface of the resistor.

[0007] A relay module according to one embodiment of the present disclosure includes the above-described current sensor and a relay connected to the current sensor via one of the first fastening portion and the second fastening portion.

[0008] The present disclosure provides a current sensor and the like that improves productivity.

[0009] FIG. 1 is a perspective view showing a first example of a current sensor according to a first embodiment. FIG. 2 is a side view of the current sensor of FIG. 1 when viewed from the Y1 direction toward the Y2 direction. FIG. 3 is a perspective view showing a second example of a current sensor according to the first embodiment. FIG. 4 is a side view of the current sensor of FIG. 3 when viewed from the Y1 direction toward the Y2 direction. FIG. 5 is a perspective view showing a third example of a current sensor according to the first embodiment. FIG. 6 is a side view of the current sensor of FIG. 5 when viewed from the Y1 direction toward the Y2 direction. FIG. 7 is a perspective view showing a fourth example of a current sensor according to the first embodiment. FIG. 8 is a top view of the current sensor of FIG. 7 when viewed from the Z1 direction toward the Z2 direction. FIG. 9 is a cross-sectional view taken along line IX-IX in FIG. 8. FIG. 10 is a perspective view showing a relay module according to a second embodiment. FIG. 11 is a side view of the relay module of FIG. 10 when viewed from the Y1 direction toward the Y2 direction.

[0010] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that each of the embodiments described below represents a specific example of the present disclosure. The numerical values, components, component placement and connection configurations, steps, step order, display examples, etc. shown in the following embodiments are merely examples and are not intended to limit the present disclosure. Therefore, among the components in the following embodiments, components that are not recited in the independent claims of the present disclosure will be described as optional components. Furthermore, each figure is not necessarily an exact illustration. In each figure, substantially identical components are assigned the same reference numerals, and redundant explanations are omitted or simplified.

[0011] Note that each figure is a schematic diagram and is not necessarily an exact illustration. Therefore, the scales and the like do not necessarily match in each figure. Furthermore, in each figure, substantially the same configuration is assigned the same reference numeral, and duplicate explanations are omitted or simplified. Furthermore, in this specification, the terms "up" and "down" do not necessarily refer to the upward direction (vertically upward) and downward direction (vertically downward) in absolute spatial recognition.

[0012] (Embodiment 1) [First Example of Current Sensor] First, a first example of a current sensor 10 according to embodiment 1 will be described with reference to Figs. 1 and 2. Fig. 1 is a perspective view showing the first example of the current sensor 10 according to embodiment 1. Fig. 2 is a side view of the current sensor 10 of Fig. 1 when viewed from the Y1 direction toward the Y2 direction. Note that the arrow drawn on the current sensor 10 shown in Fig. 2 indicates the direction of current flow.

[0013] 1, the current sensor 10 is a shunt resistor for measuring large currents. The current sensor 10 includes a first metal body 11, a second metal body 12, and a resistor 13. The current sensor 10 is formed by joining the first metal body 11 to the resistor 13 and by joining the second metal body 12 to the resistor 13. The joining of the first metal body 11 to the resistor 13 and the joining of the second metal body 12 to the resistor 13 are achieved by, for example, welding.

[0014] The first metal body 11 is a flat metal plate obtained by shearing a metal plate that has been rolled into a long shape, for example, a copper plate obtained by shearing a copper plate that has been rolled into a long shape. The first metal body 11 is a hexahedral metal plate. The first metal body 11 has a first fastening portion 14 provided on a surface perpendicular to the Z1-Z2 direction. The first fastening portion 14 is, for example, a through-hole into which a bolt can be inserted or a through-hole into which a clinching nut can be fitted. The first fastening portion 14 is also an annular through-hole.

[0015] Of the surfaces of the first metal body 11, two surfaces that are perpendicular to the X1-X2 direction are surfaces (i.e., cut surfaces) formed by shearing. Note that sagging, sheared surfaces, fractured surfaces, and burrs may be formed on the surfaces formed by shearing. In the following description, the surfaces formed by shearing are referred to as sheared surfaces.

[0016] Furthermore, of the surfaces of the first metal body 11, the four surfaces perpendicular to the Y1-Y2 direction and the Z1-Z2 direction are plate surfaces. In this specification, plate surfaces refer to surfaces that are not sheared surfaces, that is, surfaces that are formed from the time of manufacturing by rolling or the like, and exclude surfaces that are formed only by shearing after manufacturing (i.e., cut surfaces). Note that if the sheared surfaces are processed by polishing or the like, the surfaces after the processing are not included in the plate surfaces.

[0017] Like the first metal body 11, the second metal body 12 is a flat metal plate obtained by shearing a metal plate that has been rolled into a long shape, for example, a copper plate obtained by shearing a copper plate that has been rolled into a long shape. The second metal body 12 is a hexahedral metal plate. The second metal body 12 has a second fastening portion 15 provided on a surface perpendicular to the Z1-Z2 direction. The second fastening portion 15 is, for example, a through hole into which a bolt can be inserted or a through hole into which a clinching nut can be fitted. The second fastening portion 15 is also an annular through hole.

[0018] Of the surfaces of the second metal body 12, two surfaces perpendicular to the X1-X2 direction are shear surfaces, and four surfaces perpendicular to the Y1-Y2 direction and the Z1-Z2 direction are plate surfaces.

[0019] The resistor 13 is a metal having a higher resistance value than the first metal body 11 and the second metal body 12. The resistor 13 is preferably made of an alloy material having a low resistivity and a small temperature coefficient of resistance (T.C.R.), such as copper-nickel, nichrome, manganin, or iron-chromium.

[0020] Similarly to the first metal body 11, the resistor 13 is a flat metal plate obtained by shearing a metal plate that has been rolled into a long shape. The resistor 13 is a hexahedral metal plate. For example, of the faces of the resistor 13, two faces that are perpendicular to the X1-X2 direction are sheared surfaces. Of the faces of the resistor 13, four faces that are perpendicular to the Y1-Y2 direction and the Z1-Z2 direction are plate surfaces.

[0021] As shown in FIGS. 1 and 2 , the first bonding surface 16 is an interface where the plate surface of the first metal body 11 and the plate surface of the resistor 13 are bonded. The second bonding surface 17 is an interface where the plate surface of the second metal body 12 and the plate surface of the resistor 13 are bonded. In other words, the first bonding surface 16 and the second bonding surface 17 are interfaces where the first metal body 11, the second metal body 12, and the resistor 13 are bonded without using the sheared surfaces of the first metal body 11, the second metal body 12, and the resistor 13. The first bonding surface 16 and the second bonding surface 17 are located on different surfaces of the resistor 13. Specifically, the first bonding surface 16 is located on the lower surfaces of two surfaces of the resistor 13 that are perpendicular to the Z1-Z2 direction, and the second bonding surface 17 is located on the upper surfaces of two surfaces of the resistor 13 that are perpendicular to the Z1-Z2 direction.

[0022] Because the sheared surface has sagging, sheared surfaces, fractured surfaces, and burrs, the surface roughness of the sheared surface is greater than the surface roughness of the rolled plate surface. In other words, the sheared surface is rougher than the plate surface. For example, if the first bonding surface 16 and the second bonding surface 17 are formed by the sheared surfaces of the first metal body 11, the second metal body 12, and the resistor 13, poor current measurement accuracy due to misalignment of the resistor 13 or reduced dimensional accuracy of the current sensor 10, and bonding defects due to the generation of bubbles such as pits, piping, or blowholes at the first bonding surface 16 and the second bonding surface 17 are likely to occur. Because the first bonding surface 16 and the second bonding surface 17 are formed by the plate surfaces of the first metal body 11, the second metal body 12, and the resistor 13, the current sensor 10 can suppress the above-mentioned defects without additional processing of the sheared surfaces.

[0023] Furthermore, since the first metal body 11 and the second metal body 12 are hexahedrons, no additional processing such as cutting is required when processing the first metal body 11 and the second metal body 12. This allows the current sensor 10 to be manufactured without increasing the number of processes.

[0024] 2, the direction of the current flowing through the current sensor 10 is from the first metal body 11 through the resistor 13 to the second metal body 12, but this is not limited to this. The direction of the current flowing through the current sensor 10 may be from the second metal body 12 through the resistor 13 to the first metal body 11.

[0025] [Second Example of Current Sensor] Next, a second example of the current sensor 10 according to the first embodiment will be described with reference to Figs. 3 and 4. Fig. 3 is a perspective view showing the second example of the current sensor 10 according to the first embodiment. Fig. 4 is a side view of the current sensor 10 of Fig. 3 when viewed from the Y1 direction toward the Y2 direction. Note that the arrow drawn on the current sensor 10 shown in Fig. 4 indicates the direction of current flow.

[0026] The second example of the current sensor 10 differs from the first example of the current sensor 10 in that the flat plate-shaped first metal body 11 and the flat plate-shaped second metal body 12 are bent. The following description will focus on the differences from the first example of the current sensor 10, and will omit a description of the same points.

[0027] 3, the first metal body 11 has a first fastening portion 14 provided on a plane perpendicular to the Z1-Z2 direction. Furthermore, a first bonding surface 16 is located at the interface where a surface of the first metal body 11 and a surface of the resistor 13 are bonded. Similarly, the second metal body 12 has a second fastening portion 15 provided on a plane perpendicular to the Z1-Z2 direction. Furthermore, a second bonding surface 17 is located at the interface where a surface of the second metal body 12 and a surface of the resistor 13 are bonded. Furthermore, the first bonding surface 16 and the second bonding surface 17 are located on different surfaces of the resistor 13.

[0028] Of the surfaces of the resistor 13, two surfaces perpendicular to the Z1-Z2 direction are shear surfaces, and four surfaces perpendicular to the X1-X2 direction and the Y1-Y2 direction are plate surfaces.

[0029] As shown in Figures 3 and 4, the first metal body 11 and the second metal body 12 are joined to the resistor 13 so as to be arranged symmetrically with respect to the center of the resistor 13. The first metal body 11 is bent so that the surface having the first fastening portion 14 and the surface having the first bonding surface 16 intersect at 90°. The angle at which the surface having the first fastening portion 14 and the surface having the first bonding surface 16 intersect does not necessarily have to be 90°. The angle (e.g., α) at ​​which the surface having the first fastening portion 14 and the surface having the first bonding surface 16 intersect may be any of the angles 0° < α < 180° and 180° < α < 360°. The second metal body 12 is bent so that the surface having the second fastening portion 15 and the surface having the second bonding surface 17 intersect at 90°. The angle at which the plane having the second fastening portion 15 intersects with the plane having the second bonding surface 17 does not necessarily have to be 90°. The angle at which the plane having the second fastening portion 15 intersects with the plane having the second bonding surface 17 (for example, β) may be any of the angles 0°<β<180° and 180°<β<360°. The angle at which the planes intersect may be changed depending on the arrangement of the two devices fixed via the first fastening portion 14 and the second fastening portion 15. This allows the shape of the current sensor 10 to be adjusted depending on the current path between the devices being used, thereby improving the design freedom of the current sensor 10.

[0030] 3 and 4, the first metal body 11 and the second metal body 12 are processed into the shapes shown in Fig. 3 and 4 by, for example, bending the flat plate-like first metal body 11 and the second metal body 12 shown in Fig. 1 and 2. As a result, the first bonding surface 16 shown in Fig. 3 and 4 is the interface where the plate surface of the first metal body 11 and the plate surface of the resistor 13 are bonded. Similarly, the second bonding surface 17 shown in Fig. 3 and 4 is the interface where the plate surface of the second metal body 12 and the plate surface of the resistor 13 are bonded. Therefore, the current sensor 10 can suppress the occurrence of the above-mentioned defects without additionally processing the sheared surfaces.

[0031] Furthermore, similar to the first example of the current sensor 10, the first metal body 11 and the second metal body 12 are hexahedrons, and therefore no additional processing such as cutting is required when processing the first metal body 11 and the second metal body 12. This allows the current sensor 10 to be manufactured without increasing the number of processes.

[0032] [Third Example of Current Sensor] Next, a third example of the current sensor 10 according to the first embodiment will be described with reference to Figs. 5 and 6. Fig. 5 is a perspective view showing the third example of the current sensor 10 according to the first embodiment. Fig. 6 is a side view of the current sensor 10 of Fig. 5 when viewed from the Y1 direction toward the Y2 direction. Note that the arrow drawn on the current sensor 10 shown in Fig. 6 indicates the direction of current flow.

[0033] The third example of the current sensor 10 differs from the second example of the current sensor 10 in that the first metal body 11 and the second metal body 12 are each joined to the resistor 13 so that the surface having the first fastening portion 14 and the surface having the second fastening portion 15 are parallel to each other. That is, the third example of the current sensor 10 differs from the second example of the current sensor 10 in that the first metal body 11 and the second metal body 12 are each joined to the resistor 13 so that the surface having the first bonding surface 16 and the surface having the second bonding surface 17 face each other. The following description will focus on the differences from the second example of the current sensor 10, and will omit a description of the same points. Note that in FIGS. 5 and 6 , the surface having the first fastening portion 14 and the surface having the second fastening portion 15 are coplanar in the Z1-Z2 direction, but this is not a limitation. The surface having the first fastening portion 14 and the surface having the second fastening portion 15 may also be coplanar in the Z1-Z2 direction.

[0034] In order to improve the measurement accuracy of the current value, the current sensor 10 needs to equalize the current density of the current flowing through the current sensor 10. To equalize the current density, the length of the metal body in the direction of current flow must be at least a certain ratio to the width of the current sensor 10 (i.e., the length in the Y1-Y2 direction). Note that the certain ratio means, for example, a 1:1 ratio between the width of the current sensor 10 and the length of the metal body in the direction of current flow.

[0035] Furthermore, in order to increase the current flowing through the current sensor 10, Ohm's law dictates that the resistance of the current sensor 10 must be reduced. Therefore, in order to reduce the resistance of the current sensor 10, the width of the current sensor 10 must be increased. Furthermore, in order to maintain the accuracy of measuring the current value, the length of the metal body in the direction of current flow must be increased to match the width of the current sensor 10. This poses a problem in that the current sensor 10 requires a large space when fixed to a device.

[0036] 5 and 6, the third example of the current sensor 10 has a surface having a first bonding surface 16 and a surface having a second bonding surface 17 in the Z1-Z2 direction, which is a direction perpendicular to the surface having the first fastening portion 14 and the surface having the second fastening portion 15. This allows the distance between the first fastening portion 14 and the second fastening portion 15 to be shortened when connecting the current sensor 10 to a device, so the current sensor 10 can contribute to space-saving as a module.

[0037] Furthermore, similar to the second example of the current sensor 10, the angle at which the plane having the first fastening portion 14 intersects with the plane having the first bonding surface 16, and the angle at which the plane having the second fastening portion 15 intersects with the plane having the second bonding surface 17, do not necessarily have to be 90°. The angle at which each plane intersects may be changed depending on the arrangement of the devices fixed via the first fastening portion 14 and the second fastening portion 15. This allows the shape of the current sensor 10 to be adjusted depending on the current path between the devices used, thereby improving the design freedom of the current sensor 10.

[0038] Furthermore, similar to the second example of the current sensor 10, the first bonding surface 16 is an interface where the plate surface of the first metal body 11 and the plate surface of the resistor 13 are bonded. The second bonding surface 17 is an interface where the plate surface of the second metal body 12 and the plate surface of the resistor 13 are bonded. This allows the current sensor 10 to suppress the occurrence of the above-mentioned defects without additionally processing the sheared surfaces.

[0039] Furthermore, as shown in FIG. 6 , the direction of current flowing in the surface having the first bonding surface 16 is opposite to the direction of current flowing in the surface having the second bonding surface 17. Furthermore, when a current flows through the current sensor 10, magnetic flux is generated according to the right-handed screw rule. As a result, the magnetic flux generated in the surface having the first bonding surface 16 and the surface having the second bonding surface 17 is oriented in opposite directions, allowing the magnetic fluxes on each surface to cancel each other out. By suppressing the influence of the magnetic flux generated on each surface, the measurement accuracy of the current value flowing through the current sensor 10 can be improved. Note that in FIG. 6 , the direction of current flowing in the current sensor 10 is from the first metal body 11 to the second metal body 12 via the resistor 13, but this is not limited thereto. The direction of current flowing in the current sensor 10 may also be from the second metal body 12 to the first metal body 11 via the resistor 13. Even in this case, the effect obtained by the opposite current directions is the same.

[0040] [Fourth Example of Current Sensor] Next, a fourth example of the current sensor 10 according to the first embodiment will be described with reference to FIGS. 7, 8, and 9. FIG. 7 is a perspective view showing the fourth example of the current sensor 10 according to the first embodiment. FIG. 7 is an exploded view showing a connection structure between the current sensor 10 and another metal body 192. FIG. 8 is a top view of the current sensor 10 of FIG. 7 as viewed from the Z1 direction toward the Z2 direction. FIG. 9 is a cross-sectional view taken along line IX-IX of FIG. 8. FIG. 9 is a cross-sectional view as viewed from the Y1 direction toward the Y2 direction. FIGS. 8 and 9 are schematic diagrams of the current sensor 10 and the other metal bodies 191 and 192 fixed together. The other metal bodies 191 and 192 are flat metal plates having through holes.

[0041] The fourth example of the current sensor 10 differs from the third example of the current sensor 10 in that a module 18 is provided between the surface having the opposing first bonding surface 16 and the surface having the opposing second bonding surface 17. The following description will focus on the differences from the third example of the current sensor 10, and will omit a description of the same points. The module 18 is a detector for measuring the voltage across the resistor 13.

[0042] 9, the module 18 includes a first terminal 181, a second terminal 182, a third terminal 183, and an insulator 184. Note that the module 18 does not necessarily have to include the third terminal 183 and the insulator 184.

[0043] The first terminal 181 is a terminal made of a metal such as copper, and is provided on the surface having the first bonding surface 16. The first terminal 181 is connected to the first metal body 11 by being fixed to the first metal body 11 by, for example, crimping.

[0044] The second terminal 182 is a terminal made of a metal such as copper, and is provided on the surface having the second bonding surface 17. The second terminal 182 is connected to the second metal body 12 by being fixed to the second metal body 12 by crimping, for example.

[0045] The first terminal 181 and the second terminal 182 are terminals for measuring the voltage across the resistor 13. For example, if the first metal body 11 and the second metal body 12 are made of low-resistance metal plates such as copper, the voltage drop across the first metal body 11 and the second metal body 12 can be considered to be zero. As a result, the difference in voltage measured at the first terminal 181 and the second terminal 182 can be considered to be the voltage drop across the resistor 13. Therefore, by monitoring the voltage difference measured at the first terminal 181 and the second terminal 182, the current flowing through the resistor 13 can be measured with high accuracy.

[0046] The third terminal 183 is a terminal that measures the heat generated by the resistor 13. The third terminal 183 has a first metal wire 1831, a second metal wire 1832, and a thermistor 1833. The first metal wire 1831 and the second metal wire 1832 are, for example, a thermocouple. The thermistor 1833 is an electronic component whose resistance value changes with temperature changes.

[0047] The first metal wire 1831 is located between the first metal body 11 and thermistor 1833 and is connected to thermistor 1833. The second metal wire 1832 is located between the second metal body 12 and thermistor 1833 and is connected to thermistor 1833. In other words, the thermistor 1833 is located between the first metal wire 1831 and the second metal wire 1832 and is connected to both. The thermistor 1833 is also provided in a position where it contacts the resistor 13. As a result, by receiving heat emitted by the resistor 13, the resistance value of the thermistor 1833 changes and the value of the current flowing through the thermistor 1833 changes, and therefore the third terminal 183 can measure the heat emitted by the resistor 13 from the change in the current value.

[0048] The first terminal 181, the second terminal 182, and the third terminal 183 are disposed between the first metal body 11 and the second metal body 12, so that the current sensor 10 can effectively utilize the space that the current sensor 10 has when providing the module 18. This allows the current sensor 10 to contribute to space saving as a module.

[0049] The insulator 184 covers the first terminal 181, the second terminal 182, and the third terminal 183, and fills the gap between the opposing surface having the first bonding surface 16 and the surface having the second bonding surface 17. Note that the insulator 184 is preferably made of a resin that is stable against heat, since it comes into contact with the third terminal 183. For example, the resin that constitutes the insulator 184 is preferably a heat-resistant resin such as PET (Polyethylene terephthalate) resin or polycarbonate resin.

[0050] Furthermore, since the insulator 184 is embedded between the opposing first metal body 11 and second metal body 12, it is possible to prevent foreign matter such as metal bodies and magnetic bodies from entering between the first metal body 11 and the second metal body 12. This allows the current sensor 10 to suppress changes in the magnetic field generated between the first metal body 11 and the second metal body 12. This allows the current sensor 10 to improve the measurement accuracy of the current value flowing through the current sensor 10.

[0051] The surface having the first bonding surface 16 and the surface having the second bonding surface 17 may have a bent structure in order to create a space for providing the module 18. Specifically, the surface having the first bonding surface 16 and the surface having the second bonding surface 17 may have a bent structure in the middle so that the distance between them increases.

[0052] Furthermore, the resistance value of the insulator 184 is greater than the resistance value of the resistor 13. For example, the resistance value of the insulator 184 is at least 100 times, preferably at least 1,000 times, and more preferably at least 10,000 times greater than the resistance value of the resistor 13. As a result, when a current flows from the first metal body 11 to the second metal body 12, or when a current flows from the second metal body 12 to the first metal body 11, the current sensor 10 can prevent the current from flowing through the resistor 13 and the insulator 184.

[0053] As shown in FIGS. 7 and 8, the current sensor 10 may further be connected to a harness 31 which is connected to a connector 32 .

[0054] The harness 31 is a wire that connects the first terminal 181 , the second terminal 182 , and the third terminal 183 to the connector 32 .

[0055] The connector 32 is a terminal for connecting to an external measuring device.

[0056] As a result, the harness 31 and the connector 32 can pass the current detected by the first terminal 181, the second terminal 182, and the third terminal 183 to an external measuring device, so that the external measuring device connected to the connector 32 can measure the current value flowing through the resistor 13 and the heat generated by the resistor 13.

[0057] 7, 8, and 9, the current sensor 10 and the other metal bodies 191 and 192 are fixed together with nuts 21, washers 22, and bolts 23. Specifically, the bolts 23 are inserted into the through holes of the first fastening portion 14 of the first metal body 11 and the through holes of the other metal body 191, and then screwed in place with the nuts 21. Similarly, the bolts 23 are inserted into the through holes of the second fastening portion 15 of the second metal body 12 and the through holes of the other metal bodies, and then screwed in place with the nuts 21.

[0058] [Modifications of First to Fourth Examples of Current Sensor] In the first to fourth examples of the current sensor 10, the first bonding surface 16 has been described as an interface where the plate surface of the first metal body 11 and the plate surface of the resistor 13 are bonded. However, the first bonding surface 16 may be an interface where the plate surface of the first metal body 11 and the sheared surface of the resistor 13 are bonded, or may be an interface where the sheared surface of the first metal body 11 and the plate surface of the resistor 13 are bonded. Since either one of these first bonding surfaces 16 is configured as a plate surface, the above-mentioned defects can be reduced compared to when the first bonding surface 16 is an interface where the sheared surface of the first metal body 11 and the sheared surface of the resistor 13 are bonded. Also, for similar reasons, the second joining surface 17 may be an interface where the plate surface of the second metal body 12 and the shear surface of the resistor 13 are joined, or an interface where the shear surface of the second metal body 12 and the plate surface of the resistor 13 are joined.

[0059] [Effects] The current sensor 10 according to this embodiment includes a flat first metal body 11 having a first fastening portion 14, a flat second metal body 12 having a second fastening portion 15, and a flat resistor 13 joined to the first metal body 11 and the second metal body 12 and having a higher resistance value than the first metal body 11 and the second metal body 12. A first joint surface 16, which is the interface where the first metal body 11 and the resistor 13 are joined, and a second joint surface 17, which is the interface where the second metal body 12 and the resistor 13 are joined, are located on different sides of the resistor 13, and at least one of the following is satisfied: (1) the first joint surface 16 is formed by at least one of the plate surfaces of the first metal body 11 and the resistor 13, and (2) the second joint surface 17 is formed by at least one of the plate surfaces of the second metal body 12 and the resistor 13.

[0060] With this configuration, at least one of the first bonding surface 16 and the second bonding surface 17 is formed using a plate surface that is not a sheared surface, thereby reducing the occurrence of defects. This stabilizes the bonding process without additional processing of the sheared surfaces of the first metal body 11, the second metal body 12, and the resistor 13. This improves the productivity of the current sensor 10.

[0061] Furthermore, in the current sensor 10 according to this embodiment, the first metal body 11 and the second metal body 12 are joined to the resistor 13 so that when a current is passed from the first metal body 11 to the second metal body 12 via the resistor 13, or when a current is passed from the second metal body 12 to the first metal body 11 via the resistor 13, the directions of the current flow are opposite to each other.

[0062] With this configuration, the directions of the currents flowing through the first metal body 11 and the second metal body 12 are opposite to each other, and the directions of the magnetic fluxes generated in the first metal body 11 and the second metal body 12 are therefore opposite to each other. This allows the magnetic fluxes of the first metal body 11 and the second metal body 12 to cancel each other out. By suppressing the influence of the magnetic fluxes generated in the first metal body 11 and the second metal body 12, the measurement accuracy of the current value flowing through the current sensor 10 can be improved.

[0063] In addition, in the current sensor 10 of this embodiment, the first metal body 11 is bent so that the surface having the first fastening portion 14 and the surface having the first joining surface 16 intersect, and the second metal body 12 is bent so that the surface having the second fastening portion 15 and the surface having the second joining surface 17 intersect.

[0064] With this configuration, the shape of the current sensor 10 can be adjusted depending on the current path between devices to be used, and the current sensor 10 therefore improves the degree of freedom in designing an apparatus.

[0065] In addition, in the current sensor 10 according to this embodiment, at least one of the surfaces of the first metal body 11 joined at the first joint surface 16 and the surfaces of the second metal body 12 joined at the second joint surface 17 is a plate surface.

[0066] With this configuration, at least one surface of the first bonding surface 16 is a plate surface, which reduces the above-mentioned defects compared to when the first bonding surface 16 is an interface between the sheared surface of the first metal body 11 and the sheared surface of the resistor 13. Similarly, at least one surface of the second bonding surface 17 is a plate surface, which reduces the above-mentioned defects compared to when the second bonding surface 17 is an interface between the sheared surface of the second metal body 12 and the sheared surface of the resistor 13. This stabilizes the bonding process without requiring additional processing of the sheared surfaces of the first metal body 11, the second metal body 12, and the resistor 13. This improves the productivity of the current sensor 10.

[0067] In addition, in the current sensor 10 according to this embodiment, at least one of the surfaces of the resistor 13 joined at the first joining surface 16 and the surfaces of the resistor 13 joined at the second joining surface 17 is a plate surface.

[0068] With this configuration, at least one surface of the first bonding surface 16 is a plate surface, which reduces the above-mentioned defects compared to when the first bonding surface 16 is an interface between the sheared surface of the first metal body 11 and the sheared surface of the resistor 13. Similarly, at least one surface of the second bonding surface 17 is a plate surface, which reduces the above-mentioned defects compared to when the second bonding surface 17 is an interface between the sheared surface of the second metal body 12 and the sheared surface of the resistor 13. This stabilizes the bonding process without requiring additional processing of the sheared surfaces of the first metal body 11, the second metal body 12, and the resistor 13. This improves the productivity of the current sensor 10.

[0069] In the current sensor 10 according to this embodiment, the first metal body 11 and the second metal body 12 are hexahedral in shape.

[0070] With this configuration, no additional processing such as cutting is required when processing the first metal body 11 and the second metal body 12, so the current sensor 10 can be manufactured without increasing the number of processes, thereby improving the productivity of the current sensor 10.

[0071] Furthermore, in the current sensor 10 according to this embodiment, the angle at which the surface having the first fastening portion 14 intersects with the surface having the first joining surface 16 is 90°, the angle at which the surface having the second fastening portion 15 intersects with the surface having the second joining surface 17 is 90°, and the surface having the first fastening portion 14 and the surface having the second fastening portion 15 are parallel to each other.

[0072] With this configuration, when a current flows from the first metal body 11 to the second metal body 12 via the resistor 13, or when a current flows from the second metal body 12 to the first metal body 11 via the resistor 13, the directions of the currents flowing through the current sensor 10 are opposite to each other. As a result, the directions of the magnetic fluxes generated in the first metal body 11 and the second metal body 12 are opposite to each other, so that the magnetic fluxes of the first metal body 11 and the second metal body 12 can cancel each other out. By suppressing the influence of the magnetic fluxes generated in the first metal body 11 and the second metal body 12, the measurement accuracy of the current value flowing through the current sensor 10 can be improved.

[0073] Furthermore, because the surface having the first fastening portion 14 and the surface having the second fastening portion 15 are perpendicular to the surface having the first bonding surface 16 and the surface having the second bonding surface 17, the distance between the first fastening portion 14 and the second fastening portion 15 can be shortened when connecting the current sensor 10 to a device. This allows the current sensor 10 to contribute to space-saving as a module.

[0074] In addition, in the current sensor 10 according to this embodiment, the first metal body 11 and the second metal body 12 face each other, and the current sensor 10 further includes a module 18, at least a portion of which is disposed between the facing first metal body 11 and second metal body 12, and the module 18 has a first terminal 181 in contact with the first metal body 11 and a second terminal 182 in contact with the second metal body 12.

[0075] With this configuration, the first terminal 181 and the second terminal 182 are disposed between the first metal body 11 and the second metal body 12, so that the current sensor 10 can effectively utilize the space that the current sensor 10 has when providing the module 18. This allows the current sensor 10 to contribute to space saving as a module.

[0076] In the current sensor 10 according to this embodiment, the module 18 further includes a third terminal 183 that contacts the resistor 13 .

[0077] With this configuration, the third terminal 183 is disposed between the first metal body 11 and the second metal body 12, and therefore the current sensor 10 can effectively utilize the space that the current sensor 10 has when providing the module 18. This allows the current sensor 10 to contribute to space saving as a module.

[0078] In addition, in the current sensor 10 according to this embodiment, the module 18 further has an insulator 184 that fills the space between the opposing first metal body 11 and second metal body 12, and the resistance value of the insulator 184 is much greater than the resistance value of the resistor 13.

[0079] With this configuration, the insulator 184 is embedded between the opposing first metal body 11 and second metal body 12, thereby preventing foreign matter such as metal and magnetic materials from entering between the first metal body 11 and the second metal body 12. This allows the current sensor 10 to suppress changes in the magnetic field generated between the first metal body 11 and the second metal body 12. This improves the measurement accuracy of the current value flowing through the current sensor 10.

[0080] (Embodiment 2) [Configuration] The configuration of a relay module 100 according to embodiment 2 will be described with reference to Fig. 10 and Fig. 11. Fig. 10 is a perspective view showing the relay module 100 according to embodiment 2. Fig. 11 is a side view of the relay module 100 of Fig. 10 when viewed from the Y1 direction toward the Y2 direction.

[0081] 10 and 11 , the relay module 100 according to the second embodiment includes a current sensor 10, a relay 41, and a cutoff switch 42. Note that the current sensor 10 shown in FIGS. 10 and 11 is the same as the fourth example of the current sensor 10 according to the first embodiment, and therefore a description thereof will be omitted. The following description will focus on the relay 41 and the cutoff switch 42.

[0082] The relay 41 is a component that receives an electrical signal from the outside and switches an electrical circuit on and off, and is, for example, a mechanical relay or a semiconductor relay.

[0083] The cutoff switch 42 is a component that cuts off an electric circuit to protect the electric circuit from a load caused by an overload, a short circuit, etc. The cutoff switch 42 may be, for example, an irreversible switch such as a melting fuse or a pyrofuse, or a reversible switch such as a mechanical relay or a semiconductor relay.

[0084] 10 and 11 , the relay 41 is fixed to the current sensor 10 by a washer 22 and a bolt 23. The relay 41 has a threaded hole that can be screwed with the bolt 23. Specifically, the bolt 23 is inserted into the through-hole of the first fastening portion 14 of the first metal body 11 or the second fastening portion 15 of the second metal body 12, and the bolt 23 is screwed into the threaded hole of the relay 41.

[0085] Similar to the relay 41, the cutoff switch 42 is fixed to the current sensor 10 by a washer 22 and a bolt 23. The cutoff switch 42 has a threaded hole that can be screwed with the bolt 23. Specifically, the bolt 23 is inserted into a through-hole of the first fastening portion 14 of the first metal body 11 or the second fastening portion 15 of the second metal body 12, and the bolt 23 is screwed into the threaded hole that the cutoff switch 42 has.

[0086] The current sensor 10 has a surface having a first bonding surface 16 and a surface having a second bonding surface 17 in the Z1-Z2 direction, which is a direction perpendicular to the surface having the first fastening portion 14 and the surface having the second fastening portion 15. This allows the current sensor 10 to fix the relay 41 and the cutoff switch 42 with a short distance between them, thereby contributing to space-saving of the relay module 100.

[0087] The current sensor 10 provided in the relay module 100 may be any of the first, second, third, and fourth examples of the current sensor 10 according to embodiment 1.

[0088] [Effect] The relay module 100 of this embodiment comprises the current sensor 10 of embodiment 1 and a relay 41 connected to the current sensor 10 via one of the first fastening portion 14 and the second fastening portion 15.

[0089] With this configuration, the relay module 100 is manufactured using the current sensor 10 with improved productivity, and therefore the productivity of the relay module 100 is improved.

[0090] In addition, the relay module 100 of this embodiment further includes a cut-off switch 42, which is connected to the current sensor 10 via the other of the first fastening portion 14 and the second fastening portion 15 that is not connected to the relay 41.

[0091] With this configuration, the relay module 100 is manufactured using the current sensor 10 with improved productivity, and therefore the productivity of the relay module 100 is improved.

[0092] [Modifications] While the current sensor and relay module according to one or more aspects have been described based on the above-described embodiments, the present disclosure is not limited to the above-described embodiments. As long as they do not deviate from the spirit of the present disclosure, various modifications conceivable by those skilled in the art to the above-described embodiments and configurations constructed by combining components of different embodiments may also be included within the scope of one or more aspects.

[0093] [Additional Notes] The above description of the embodiments discloses the following techniques.

[0094] (Technology 1) A current sensor comprising: a flat first metal body having a first fastening portion; a flat second metal body having a second fastening portion; and a flat resistor joined to the first metal body and the second metal body and having a higher resistance value than the first metal body and the second metal body, wherein a first joint surface which is the interface where the first metal body and the resistor are joined, and a second joint surface which is the interface where the second metal body and the resistor are joined, are located on different sides of the resistor, and at least one of the following is satisfied: (1) the first joint surface is composed of at least one of the plate surfaces of the first metal body and the plate surface of the resistor; and (2) the second joint surface is composed of at least one of the plate surfaces of the second metal body and the plate surface of the resistor.

[0095] (Technology 2) A current sensor according to Technology 1, wherein the first metal body and the second metal body are joined to the resistor so that when a current is passed from the first metal body to the second metal body via the resistor, or when a current is passed from the second metal body to the first metal body via the resistor, the directions of the current flow are opposite to each other.

[0096] (Technology 3) A current sensor described in Technology 1 or 2, wherein the first metal body is bent so that the surface having the first fastening portion and the surface having the first joint surface intersect, and the second metal body is bent so that the surface having the second fastening portion and the surface having the second joint surface intersect.

[0097] (Technology 4) A current sensor described in any one of Technologies 1 to 3, wherein at least one of the surface of the first metal body joined at the first joint surface and the surface of the second metal body joined at the second joint surface is a plate surface.

[0098] (Technology 5) A current sensor described in any one of Technologies 1 to 4, wherein at least one of the surfaces of the resistor joined at the first bonding surface and the surfaces of the resistor joined at the second bonding surface is a plate surface.

[0099] (Technology 6) The current sensor according to any one of Technologies 1 to 5, wherein the first metal body and the second metal body are hexahedral in shape.

[0100] (Technology 7) A current sensor described in any one of technologies 1 to 6, wherein the angle at which the surface having the first fastening portion and the surface having the first joint surface intersect is 90°, the angle at which the surface having the second fastening portion and the surface having the second joint surface intersect is 90°, and the surface having the first fastening portion and the surface having the second fastening portion are parallel to each other.

[0101] (Technology 8) A current sensor described in any one of Technologies 1 to 7, wherein the surface of the first metal body and the surface of the second metal body are opposed to each other, and the current sensor further includes a module at least a portion of which is disposed between the opposed first metal body and the second metal body, and the module has a first terminal in contact with the first metal body and a second terminal in contact with the second metal body.

[0102] (Technology 9) The current sensor according to Technology 8, wherein the module further has a third terminal in contact with the resistor.

[0103] (Technology 10) A current sensor described in Technology 8 or 9, wherein the first metal body and the second metal body face each other, the module further has an insulator filling the space between the first metal body and the second metal body, and the resistance value of the insulator is greater than the resistance value of the resistor.

[0104] (Technology 11) A relay module comprising: a current sensor according to any one of technologies 1 to 10; and a relay connected to the current sensor via one of the first fastening portion and the second fastening portion.

[0105] (Technology 12) The relay module described in Technology 11, further comprising a cut-off switch, the relay being connected to one of the first fastening portion and the second fastening portion, and the cut-off switch being connected to the current sensor via the other of the first fastening portion and the second fastening portion.

[0106] The current sensor and relay module according to the present disclosure is useful, for example, in the manufacture of shunt resistors.

[0107] 10 Current sensor 11 First metal body 12 Second metal body 13 Resistor 14 First fastening portion 15 Second fastening portion 16 First joint surface 17 Second joint surface 18 Module 181 First terminal 182 Second terminal 183 Third terminal 1831 First metal wire 1832 Second metal wire 1833 Thermistor 184 Insulator 191, 192 Other metal body 21 Nut 22 Washer 23 Bolt 31 Harness 32 Connector 41 Relay 42 Cut-off switch 100 Relay module

Claims

1. A flat first metal body having a first fastening portion, a flat second metal body having a second fastening portion, and a flat resistor joined to the first metal body and the second metal body and having a higher resistance value than the first metal body and the second metal body, wherein a first joint surface, which is an interface where the first metal body and the resistor are joined, and a second joint surface, which is an interface where the second metal body and the resistor are joined, are located on different surfaces of the resistor, and at least one of the following is satisfied: (1) the first joint surface is composed of at least one of the plate surfaces of the first metal body and the resistor; and (2) the second joint surface is composed of at least one of the plate surfaces of the second metal body and the resistor. A current sensor.

2. The current sensor according to claim 1, wherein the first metal body and the second metal body are joined to the resistor such that when a current flows from the first metal body through the resistor to the second metal body or when a current flows from the second metal body through the resistor to the first metal body, the directions of the flowing currents are opposite to each other.

3. The current sensor according to claim 1 or 2, wherein the first metal body is bent such that the surface having the first fastening portion and the surface having the first joint surface intersect, and the second metal body is bent such that the surface having the second fastening portion and the surface having the second joint surface intersect.

4. The current sensor according to any one of claims 1 to 3, wherein at least one of the surface of the first metal body joined at the first joint surface and the surface of the second metal body joined at the second joint surface is a plate surface.

5. The current sensor according to any one of claims 1 to 4, wherein at least one of the surface of the resistor joined at the first joint surface and the surface of the resistor joined at the second joint surface is a plate surface.

6. The current sensor according to any one of claims 1 to 5, wherein the shape of the first metal body and the shape of the second metal body are hexahedrons.

7. The angle at which the surface having the first fastening portion intersects the surface having the first joining surface is 90°, the angle at which the surface having the second fastening portion intersects the surface having the second joining surface is 90°, and the surface having the first fastening portion and the surface having the second fastening portion are in a parallel relationship with each other. The current sensor according to any one of claims 1 to 6.

8. The surface of the first metal body and the surface of the second metal body face each other, and the current sensor further includes a module at least partially disposed between the opposing first metal body and the second metal body. The module has a first terminal that contacts the first metal body and a second terminal that contacts the second metal body. The current sensor according to any one of claims 1 to 7.

9. The module further has a third terminal that contacts the resistor. The current sensor according to claim 8.

10. The first metal body and the second metal body face each other, the module further has an insulator that fills the space between the first metal body and the second metal body, and the resistance value of the insulator is greater than the resistance value of the resistor. The current sensor according to claim 8 or 9.

11. A current sensor according to any one of claims 1 to 10, and a relay connected to the current sensor via one of the first fastening portion and the second fastening portion. A relay module comprising.

12. The relay module further includes a cutoff switch. The relay is connected to one of the first fastening portion and the second fastening portion, and the cutoff switch is connected to the current sensor via the other of the first fastening portion and the second fastening portion. The relay module according to claim 11.

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