Shunt Resistor and Current Detection Device

Abstract

The present application relates to a shunt resistor and a current detection device. The present application provides a shunt resistor capable of reducing the absolute value of the resistor temperature coefficient. The shunt resistor (1) includes: a base portion (9) composed of a resistor body (5) and a pair of electrodes (6, 7); a bridge portion (70) that bridges the pair of electrodes (6, 7) and is composed of a conductor; and connection portions (71, 72) that connect the pair of electrodes (6, 7) and the bridge portion (70). The bridge portion (70) has a resistance value higher than the resistance value of the base portion (9) at the connection portions (71, 72).

Description

Technical Field

[0001] The present invention relates to a shunt resistor and a current detection device. Background Art

[0002] Shunt resistors are widely used for current detection purposes. Such a shunt resistor includes a resistor body and electrodes joined to both ends of the resistor body. Generally, the resistor body is made of a resistance alloy such as a copper-nickel alloy, a copper-manganese alloy, an iron-chromium alloy, or a nickel-chromium alloy, and the electrodes are made of a highly conductive metal such as copper. A voltage detection unit is provided at the electrode, and a wire (for example, an aluminum wire) is connected to the voltage detection unit to detect the voltage at the voltage detection unit.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2007-329421

[0006] Patent Document 2: Japanese Patent Application Laid-Open No. 2013-504213

[0007] Patent Document 3: Japanese Unexamined Patent Application Publication No. 2020-102626 Summary of the Invention

[0008] In a shunt resistor, in order to be able to detect a current under conditions with little influence caused by temperature variation, the characteristic of the resistance temperature coefficient (TCR) is important. In addition, the resistance temperature coefficient is an index indicating the ratio of the change in the resistance value caused by temperature, and the smaller its absolute value, the smaller the change in the resistance value.

[0009] Therefore, an object of the present invention is to provide a shunt resistor and a current detection device capable of reducing the absolute value of the resistance temperature coefficient.

[0010] In one aspect, there is provided a shunt resistor for current detection. The shunt resistor includes: a base portion composed of a resistor body and a pair of electrodes connected to both ends of the resistor body; a bridge portion bridging the pair of electrodes and made of a conductor; and a connection portion connecting the pair of electrodes and the bridge portion. The bridge portion has a higher resistance value than the resistance value of the base portion at the connection portion.

[0011] In one aspect, the bridge portion has a smaller size than the size of the base portion.

[0012] In one aspect, the connection portion is arranged along the joint portion of the pair of electrodes with the resistor body.

[0013] In one aspect, the bridge portion includes voltage detection portions arranged on both end portions sides of the bridge portion.

[0014] In one aspect, the bridge portion includes a slit portion disposed between the connection portion and the voltage detection portion.

[0015] In one aspect, the shunt resistor includes a voltage detection portion disposed adjacent to the connection portion.

[0016] In one aspect, the bridge portion has a plate shape and is bent in a direction perpendicular to the length direction of the resistor body.

[0017] In one aspect, there is provided a current detection device including the above-described shunt resistor and a current detection circuit board having a voltage signal wiring for transmitting a voltage signal from the shunt resistor. The bridge portion includes voltage detection portions disposed on both end portions sides of the bridge portion, and the current detection circuit board includes voltage terminal pads connected to the voltage detection portions.

[0018] The shunt resistor includes a base portion composed of a resistor body and a pair of electrodes, and a bridge portion having a resistance value higher than the resistance value of the base portion at the connection portion. A shunt resistor having such a configuration can reduce the absolute value of its resistance temperature coefficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a diagram showing one embodiment of the shunt resistor.

[0020] Figure 2 is a graph showing the rate of change of the resistance value of the shunt resistor without a bridge portion as a comparative example with respect to temperature change.

[0021] Figure 3 is a graph showing the rate of change of the resistance value of the shunt resistor of the present embodiment with respect to temperature change.

[0022] Figure 4 is a diagram showing another embodiment of the bridge portion.

[0023] Figure 5 is a diagram showing another embodiment of the shunt resistor including a bridge portion.

[0024] Figure 6 is a diagram showing another embodiment of the shunt resistor including a bridge portion.

[0025] Figure 7 is a diagram showing another embodiment of the shunt resistor including a bridge portion.

[0026] Figure 8 of Figure 8 (a) is a diagram showing a bridge portion having a linear shape, Figure 8 (b) is a diagram showing a bridge portion having an arch shape.

[0027] Figure 9 It is a diagram showing other embodiments of the bridge portion.

[0028] Figure 10 It is a view from the side Figure 9 of the bridge portion shown.

[0029] Figure 11 of Figure 11 (a) to Figure 11 (c) are diagrams showing examples of methods for determining the detection voltage value.

[0030] Figure 12 It is a diagram showing the size of the slit portion formed in the bridge portion.

[0031] Figure 13 It is a graph showing the adjustment of the resistance temperature coefficient by changing the size of the slit portion.

[0032] Figure 14 of Figure 14 (a) is a diagram showing a current detection device, Figure 14 (b) is a view from the side Figure 14 of the current detection device shown in (a).

[0033] Figure 15 It is a diagram showing a current detection circuit board having a voltage signal wiring.

[0034] Figure 16 of Figure 16 (a) is a diagram showing a current detection circuit board mounted on a shunt resistor via a bridge portion, Figure 16 (b) is a diagram showing the bending position of the bridge portion.

[0035] Figure 17 It is a diagram showing a current detection circuit board mounted on a shunt resistor via two bridge portions.

[0036] Figure 18 It is a diagram showing a current detection circuit board mounted on a shunt resistor via a bridge portion bent in a U shape.

[0037] (Symbol description)

[0038] 1: Shunt resistor; 5: Resistor body; 5a, 5b: Both-side connection surfaces; 6: Electrode; 6a: Contact surface; 6b: Side surface; 6c: Side surface; 6d: Upper surface; 7: Electrode; 7a: Contact surface; 7b: Side surface; 7c: Side surface; 7d: Upper surface; 9: Base; 30: Current detection device; 34: Current detection circuit board; 36, 37: Pad for voltage terminal; 46, 47: Voltage signal wiring; 50: Ground wiring; 70: Bridge portion; 70A: Bridge portion; 70B: Bridge portion; 71, 72: Connection portion; 71A, 72A: Connection portion; 71B, 72B: Connection portion; 75: Resistor portion; 75A, 75B: Resistor portion; 76, 77: Electrode portion; 76A, 77A: Electrode portion; 76B, 77B: Electrode portion; 78A, 78B, 78C: Voltage detection portion; 79A, 79B, 79C: Voltage detection portion; 81a, 81b: Voltage detection portion; 82a, 82b: Voltage detection portion; 83, 84: Connection terminal; 85, 86: Base end portion; 91, 92: Voltage detection portion; 91A, 92A: Voltage detection portion; 91B, 92B: Voltage detection portion; 95, 96, 97, 98: Slit portion. Detailed implementation manner

[0039] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, in the drawings described below, the same or corresponding structural elements are denoted by the same reference numerals and repeated description is omitted. In the following multiple embodiments, the structure of one embodiment not specifically described is the same as that of other embodiments, so the repeated description thereof is omitted.

[0040] Figure 1 is a diagram showing one embodiment of the shunt resistor. As Figure 1 shown, the shunt resistor 1 includes: a resistor body 5 made of a resistor alloy plate having a prescribed thickness and a prescribed width; and a pair of electrodes 6 and 7 connected to both ends (i.e., both-side connection surfaces) 5a and 5b of the resistor body 5 in the first direction and made of a highly conductive metal. The resistor body 5 and the pair of electrodes 6 and 7 constitute a base 9.

[0041] The electrode 6 has a contact surface 6a that contacts one end (one connection surface) 5a of the resistor body 5, and the electrode 7 has a contact surface 7a that contacts the other end (the other connection surface) 5b of the resistor body 5. Screw holes (not shown) for connecting the shunt resistor 1 and a wiring component (bus bar) not shown by screws are respectively formed in the electrodes 6 and 7.

[0042] As Figure 1As shown, the first direction is the length direction of the resistor body 5, which corresponds to the length direction of the shunt resistor 1. The length direction of the shunt resistor 1 is the direction in which the electrodes 6, the resistor body 5, and the electrode 7 are arranged in sequence. The direction perpendicular to the first direction is the second direction. The second direction is the width direction of the shunt resistor 1. As Figure 1 shown, the electrodes 6 and 7 have the same structure and are arranged symmetrically with respect to the resistor body 5.

[0043] Both ends 5a and 5b of the resistor body 5 are respectively connected (joined) to the electrodes 6 and 7 by means such as welding (for example, electron beam welding, laser beam welding, or hard soldering, soft soldering). As an example of the material of the resistor body 5, a low-resistance alloy material such as a Cu-Mn based alloy can be cited. As an example of the material of the electrodes 6 and 7, copper (Cu) can be cited. The resistor body 5 has a higher resistivity than the electrodes 6 and 7.

[0044] The shunt resistor 1 further includes a bridge portion 70 that bridges a pair of electrodes 6 and 7 and is made of a conductor. The shunt resistor 1 further includes connection portions 71 and 72 that connect the pair of electrodes 6 and 7 and the bridge portion 70. The connection portion 71 connects the electrode 6 and the bridge portion 70 by means such as welding (for example, electron beam welding, laser beam welding, or hard soldering, soft soldering). Similarly, the connection portion 72 connects the electrode 7 and the bridge portion 70 by means such as welding (for example, electron beam welding, laser beam welding, or hard soldering, soft soldering).

[0045] The bridge portion 70 is arranged above the resistor body 5 so as to straddle the electrodes 6 and 7. The shunt resistor 1 having the bridge portion 70 is configured to shunt a part of the main current passing through the shunt resistor 1 (refer to Figure 1 ).

[0046] The bridge portion 70 has a higher resistance value than the resistance value of the base portion 9 at the connection portions 71 and 72 (the resistance value of the bridge portion 70 at the connection portions 71 and 72 > the resistance value of the base portion 9 at the connection portions 71 and 72). The bridge portion 70 has a smaller size than the base portion 9. In Figure 1 the embodiment shown, the bridge portion 70 includes: a resistance portion 75 made of the same material as the resistor body 5 (for example, a low-resistance alloy) and a pair of electrode portions 76 and 77 connected to both ends of the resistance portion 75. The electrode portions 76 and 77 are made of the same material as the electrodes 6 and 7 (for example, copper). The resistance portion 75 has a higher resistivity than the electrode portions 76 and 77. In one embodiment, the bridge portion 70 may also be made of a single conductor such as copper. The resistance portion 75 may be made of a material different from that of the resistor body 5, and the electrode portions 76 and 77 may be made of a material different from that of the electrodes 6 and 7.

[0047] The electrode portion 76, the resistance portion 75, and the electrode portion 77 are arranged in sequence in the first direction of the shunt resistor 1. The resistance portion 75 is connected (joined) to the electrode portions 76 and 77 respectively by means such as welding (for example, electron beam welding, laser beam welding, or hard soldering, soft soldering).

[0048] In Figure 1 the illustrated embodiment, the electrode portions 76 and 77 correspond to a voltage detection portion for detecting the voltage between a pair of electrode portions 76 and 77. In other words, the electrode portions 76 and 77 are provided with a voltage detection portion. In one embodiment, the connection portions 71 and 72 may also correspond to the voltage detection portion. In one embodiment, the electrodes 6 and 7 adjacent to the connection portions 71 and 72 may also correspond to the voltage detection portion.

[0049] Figure 2 is a graph showing the rate of change of the resistance value of a shunt resistor without a bridge portion as a comparative example with temperature change. Figure 3 is a graph showing the rate of change of the resistance value of the shunt resistor of the present embodiment with temperature change. In Figure 2 and Figure 3 each, the horizontal axis represents the temperature of the shunt resistor, and the vertical axis represents the rate of change of the resistance value of the shunt resistor.

[0050] From the comparison of the rate of change of the resistance value of the shunt resistor 1 according to the present embodiment with the rate of change of the resistance value of the shunt resistor as a comparative example, it can be clarified that the shunt resistor 1 of the present embodiment can reduce the rate of change of the resistance value caused by temperature change. Thus, the shunt resistor 1 having the bridge portion 70 can reduce the absolute value of the resistance temperature coefficient (TCR).

[0051] Figure 4 is a diagram showing another embodiment of the bridge portion. As Figure 4 shown, the size of the bridge portion 70 may also have a long width shape in the second direction. According to such a structure, the electrode portions 76 and 77 of the bridge portion 70 can each have a plurality of voltage detection portions.

[0052] In Figure 4 the illustrated embodiment, the electrode portion 76 is provided with voltage detection portions 78A, 78B, and 78C arranged along the joint portion (i.e., the contact surfaces 6a and 7a) of the electrodes 6 and 7 with the resistor body 5. Similarly, the electrode portion 77 is provided with voltage detection portions 79A, 79B, and 79C arranged along the joint portion (i.e., the contact surfaces 6a and 7a) of the electrodes 6 and 7 with the resistor body 5. Thus, the voltage detection portions 78A to 78C and the voltage detection portions 79A to 79C are arranged along the second direction of the shunt resistor 1.

[0053] In Figure 1In the illustrated embodiment, the connecting portions 71 and 72 of the bridge portion 70 are arranged in the central portion of the resistor body 5 in the second direction of the shunt resistor 1. In one embodiment, the connecting portions 71 and 72 may also be arranged along the joint portions (i.e., the contact surfaces 6a and 7a) of the pair of electrodes 6 and 7 with the resistor body 5. In other words, the bridge portion 70 may also be arranged adjacent to the resistor body 5 in the second direction of the shunt resistor 1. Hereinafter, other arrangement examples of the bridge portion 70 will be described with reference to the drawings.

[0054] Figures 5 to 7 FIG. is a view showing another embodiment of a shunt resistor having a bridge portion. As Figure 5 shown, the bridge portion 70 may also be connected to the side surfaces 6c and 7c of the electrodes 6 and 7 in the second direction. In Figure 5 the illustrated embodiment, the bridge portion 70 connected to the side surfaces 6c and 7c in the second direction is arranged above the resistor body 5.

[0055] In Figure 6 the illustrated embodiment, the shunt resistor 1 includes a bridge portion 70A connected to the side surfaces 6c and 7c of the electrodes 6 and 7 in the second direction and a bridge portion 70B connected to the side surfaces 6b and 7b of the electrodes 6 and 7 in the second direction. The bridge portions 70A and 70B are arranged above the resistor body 5.

[0056] The bridge portion 70A includes a resistor portion 75A and a pair of electrode portions 76A and 77A, and is connected to the pair of electrodes 6 and 7 through connecting portions 71A and 72A. Similarly, the bridge portion 70B includes a resistor portion 75B and a pair of electrode portions 76B and 77B, and is connected to the pair of electrodes 6 and 7 through connecting portions 71B and 72B. Thus, in Figure 6 the illustrated embodiment, the bridge portions 70A and 70B have the same structure as each other.

[0057] In Figure 7 the illustrated embodiment, the bridge portion 70 connected to the side surfaces 6b and 7b of the electrodes 6 and 7 is arranged on the side of the resistor body 5, and a gap is formed between the resistor portion 75 of the bridge portion 70 and the resistor body 5. Although not shown, the bridge portion 70 may also be connected to the side surfaces 6c and 7c of the electrodes 6 and 7. In addition, although not shown, Figure 7 the illustrated embodiment may also be combined with Figure 5 the illustrated embodiment and / or Figure 6 the illustrated embodiment.

[0058] In Figures 1 to 6 the illustrated embodiment, the bridge portion 70 is arranged on the surface side of the resistor body 5, but in one embodiment, the bridge portion 70 may also be arranged on the back side of the resistor body 5.

[0059] Figure 8(a) is a diagram showing a bridge portion having a linear shape. Figure 8 (b) is a diagram showing a bridge portion having an arch shape. Figure 8 The bridge portion 70 of the embodiment shown in (a) corresponds to Figures 1 to 7 the bridge portion 70 of the embodiment shown. In Figure 8 the embodiment shown in (a), the bridge portion 70 has a linear shape. The upper surface 5c of the resistor body 5 is arranged at a height lower than the upper surfaces 6d, 7d of the electrodes 6, 7. Therefore, the linear-shaped bridge portion 70 is arranged above the upper surface 5c of the resistor body 5. As a result, a gap is formed between the resistor portion 75 of the bridge portion 70 and the resistor body 5, and the bridge portion 70 does not contact the resistor body 5.

[0060] As Figure 8 shown in (b), the upper surface 5c of the resistor body 5 is arranged at the same height as the upper surfaces 6d, 7d of the electrodes 6, 7. The bridge portion 70 has a plate shape and is bent in the bridging direction. More specifically, the bridge portion 70 has an arch shape bent in a direction away from the upper surface 5c of the resistor body 5. Therefore, the bridge portion 70 is arranged above the upper surface 5c of the resistor body 5, and a gap is formed between the resistor portion 75 of the bridge portion 70 and the resistor body 5.

[0061] Figure 9 is a diagram showing another embodiment of the bridge portion. As Figure 9 shown, the bridge portion 70 includes: voltage detection portions 81a, 81b, 82a, 82b that detect the voltage between the detection electrode portions 76, 77; and connection terminals 83, 84 that are connected to the electrodes 6, 7. The voltage detection portions 81a, 81b, 82a, 82b are arranged on both end portions sides of the bridge portion 70. In Figure 9 the embodiment shown, the voltage detection portions 81a, 81b and the connection terminal 83 are formed on the electrode portion 76, and the voltage detection portions 82a, 82b and the connection terminal 84 are formed on the electrode portion 77.

[0062] The voltage detection portions 81a, 81b, 82a, 82b may also be voltage detection terminals, and the voltage is detected by means of respectively connecting wires (for example, aluminum wires) to these voltage detection portions 81a, 81b, 82a, 82b, or by inserting the voltage detection portions 81a, 81b, 82a, 82b, which are voltage detection terminals, into through holes formed in the circuit board and conducting connection with the wiring formed on the circuit board.

[0063] As Figure 9As shown, the bridge portion 70 includes slit portions 95, 96, 97, and 98. The slit portion 95 is formed between the voltage detection portion 81a and the connection terminal 83, and the slit portion 96 is formed between the voltage detection portion 81b and the connection terminal 83. The slit portion 97 is formed between the voltage detection portion 82a and the connection terminal 84, and the slit portion 98 is formed between the voltage detection portion 82b and the connection terminal 84.

[0064] Figure 10 is a view of the bridge portion as viewed from the side. As Figure 9 shown. Figure 10 As shown, the voltage detection portions 81a (81b) and the voltage detection portions 82a (82b) are arranged in a direction away from the electrodes 6 and 7 and do not contact the electrodes 6 and 7. In one embodiment, if the voltage detection portions 81a (81b) and the voltage detection portions 82a (82b) do not contact the electrodes 6 and 7, they do not need to be arranged in a direction away from the electrodes 6 and 7. For example, the voltage detection portions 81a (81b) and the voltage detection portions 82a (82b) may also extend in the horizontal direction.

[0065] In Figure 9 and Figure 10 the embodiments shown, the electrode portions 76 and 77 have base end portions 85 and 86 adjacent to the resistance portion 75, and the voltage detection portions 81a, 81b, 82a, 82b and the connection terminals 83 and 84 are connected to the base end portions 85 and 86. In one embodiment, the voltage detection portions 81a, 81b, 82a, 82b may also be components different from the electrode portions 76 and 77. In this case, the voltage detection portions 81a, 81b, 82a, 82b may also be arranged adjacent to the connection terminals 83 and 84.

[0066] In the present embodiment, the electrode portion 76 includes two voltage detection portions 81a and 81b, and the electrode portion 77 includes two voltage detection portions 82a and 82b. In one embodiment, the electrode portions 76 and 77 may each include a single terminal portion.

[0067] Figure 11 (a) to Figure 11 (c) are diagrams showing examples of methods for determining the detected voltage value. As Figure 11As shown in (a), when the voltage detection units 81a and 81b are provided in the electrode unit 76 and the voltage detection units 82a and 82b are provided in the electrode unit 77, it is also possible to average the voltage values obtained by combining the voltage value V1 detected between the voltage detection unit 81a and the voltage detection unit 82a and the voltage value V2 detected between the voltage detection unit 81b and the voltage detection unit 82b, and determine the averaged voltage value Vav as the detected voltage value. Thus, it is also possible to detect the voltage values between the voltage detection units arranged along the second direction of the shunt resistor 1, and determine the average value of the detected voltage values as the detected voltage value.

[0068] In one embodiment, as Figure 11 shown in (b), it is also possible to average the voltage values obtained by combining the voltage value V1 detected between the voltage detection unit 81a and the voltage detection unit 82b and the voltage value V2 detected between the voltage detection unit 82a and the voltage detection unit 81b, and determine the averaged voltage value Vav as the detected voltage value. Thus, it is also possible to detect the voltage values between the voltage detection units arranged diagonally in the second direction of the shunt resistor 1, and determine the average value of the detected voltage values as the detected voltage value.

[0069] In one embodiment, as Figure 11 shown in (c), it is also possible to electrically connect the voltage detection unit 81a and the voltage detection unit 81b, electrically connect the voltage detection unit 82a and the voltage detection unit 82b, and determine the voltage value V1 detected between the mutually connected voltage detection unit 81a and the voltage detection unit 81b and the mutually connected voltage detection unit 82a and the voltage detection unit 82b as the detected voltage value.

[0070] According to Figure 11 the method for determining the detected voltage value shown in (a) to Figure 11 (c), since the shunt resistor 1 detects the voltages of multiple parts from the same electrode side, it has redundancy. In the shunt resistor 1, the potential distributions of the electrodes 6 and 7 change according to the direction (current path) of the connecting wiring component (bus bar), but according to Figure 11 the method for determining the detected voltage value shown in (a) to Figure 11 (c), it is possible to reduce the influence on the resistance temperature coefficient (TCR) caused by the change in this potential distribution, and it is possible to connect the wiring component (bus bar) without restricting the connection method.

[0071] Although not shown, Figure 4 and Figure 6 the shunt resistor 1 of the embodiment shown can also detect the voltages of multiple parts from the same electrode side in the same manner as the shunt resistor 1 of the embodiment shown in Figure 11 (a) to Figure 11 (c). In Figure 4 andFigure 6 In the illustrated embodiment, it is also possible to achieve the same effect as the embodiment shown in Figure 11 (a) to Figure 11 (c).

[0072] When a single voltage detection unit is provided in each of the electrode units 76 and 77, the voltage value detected between these voltage detection units may be determined as the detection voltage value.

[0073] Figure 12 FIG. is a diagram showing the size of the slit portion formed in the bridge portion. Figure 13 FIG. is a graph showing the resistance temperature coefficient adjusted by changing the size of the slit portion. As Figure 12 and Figure 13 shown, by changing the dimensions of the slit portion 96 (and the slit portions 95, 97, 98), the resistance temperature coefficient of the shunt resistor 1 can be adjusted.

[0074] The slit portions 95, 96, 97, 98 have the same structure, and the sizes of all the slit portions 95, 96, 97, 98 can be changed. Therefore, the structure of the slit portion 96 will be described below. As Figure 12 shown, by changing the distance Da of the base end portion 85 in the first direction, the length of the slit portion 96 in the first direction can be changed. By changing the distance Db between the voltage detection unit 81b and the connection terminal 83, the length of the slit portion 96 in the second direction can be changed. The distance Da is related to the depth of the slit portion and is the distance between the bottom of the depth of the slit portion and the resistor portion 75.

[0075] In Figure 13 the graph shown, the resistance temperature coefficient of the shunt resistor 1 when the distance Da is changed is shown. As Figure 13 shown, when the distance Da is large (the depth of the slit portion is shallow), the relationship between temperature and the rate of change shows a curve rising to the right (i.e., a positive resistance temperature coefficient). On the other hand, when the distance Da is small (the depth of the slit portion is deep), the relationship between temperature and the rate of change shows a curve falling to the right (i.e., a negative resistance temperature coefficient). That is, by changing the distance Da (the depth of the slit portion), the slope of the curve representing the resistance temperature coefficient can be adjusted. In addition, by changing the distance Db (the width of the slit portion), the slope of the curve representing the resistance temperature coefficient can also be adjusted. When the distance Db is decreased, the resistance temperature coefficient can be adjusted to the positive side, and when the distance Db is increased, the resistance temperature coefficient can be adjusted to the negative side.

[0076] In Figure 12In the illustrated embodiment, a structure for adjusting the resistance temperature coefficient of the shunt resistor 1 by changing the dimensions of the slit portion 96 is described. However, in one embodiment, the resistance temperature coefficient of the shunt resistor 1 can be adjusted by changing the mounting position of the bridge portion 70, the shape of the shunt resistor 1 (such as the length, width, thickness, etc. of the electrodes 6, 7, and the resistor body 5), and the material of the resistor body 5.

[0077] Figure 14 (a) is a diagram showing a current detection device. Figure 14 (b) is a view from the side of Figure 14 the current detection device shown in (a). Figure 15 is a diagram showing a current detection circuit board having voltage signal wirings. As Figure 14 (a), Figure 14 (b), and Figure 15 shown, the current detection device 30 includes a shunt resistor 1 and a current detection circuit board 34. The current detection circuit board 34 is disposed on the shunt resistor 1.

[0078] As Figure 15 shown, the current detection circuit board 34 includes voltage signal wirings 46, 47 that transmit a voltage signal from the shunt resistor 1 to an output connector (output terminal) 35; a ground wiring 50; and voltage terminal pads (more specifically, copper foil portions) 36, 37.

[0079] One end of the voltage signal wiring 46 is connected to the voltage terminal pad 36, and the other end is connected to the output connector 35. The output connector 35 is an output terminal for outputting the voltage signal from the shunt resistor 1. One end of the voltage signal wiring 47 is connected to the voltage terminal pad 37, and the other end is connected to the output connector 35. One end of the ground wiring 50 is connected to the voltage terminal pad 36, and the other end is connected to the output connector 35. In one embodiment, it is also possible that one end of the ground wiring 50 is connected to the voltage terminal pad 37, and the other end is connected to the output connector 35.

[0080] The voltage terminal pad 36 is electrically connected to an electrode portion (i.e., a voltage detection portion) 76 via an internal wiring (not shown) of the current detection circuit board 34. The voltage terminal pad 37 is electrically connected to an electrode portion (i.e., a voltage detection portion) 77 via an internal wiring (not shown) of the current detection circuit board 34.

[0081] The above-mentioned internal wiring and the electrode parts (i.e., voltage detection parts) 76 and 77 are connected by means such as soldering. In one embodiment, voltage detection terminals (vertically extending conductive pins) are provided on the electrode parts (i.e., voltage detection parts) 76 and 77 by means such as soldering, and connection is made by means of connecting a wire (e.g., an aluminum wire) to the voltage detection terminals and inserting the voltage detection terminals into through holes formed in the circuit board.

[0082] An operator connects a cable having a connector that fits with the output connector 35 to measure the voltage between the electrode parts (i.e., voltage detection parts) 76 and 77. With such a structure, the voltage between the electrode parts (i.e., voltage detection parts) 76 and 77 can be measured simply. In one embodiment, an operational amplifier (amplifier) for amplifying the voltage signal from the shunt resistor 1, an A / D converter, and / or a temperature sensor, etc. may be mounted on the current detection circuit board 34.

[0083] Figure 16 (a) is a diagram showing a current detection circuit board mounted on a shunt resistor via a bridge part. Figure 16 (b) is a diagram showing the bending position of the bridge part. In the present embodiment, in the second direction of the shunt resistor 1, the bridge part 70 is bent at its central part to have an L shape. The bridge part 70 includes connection terminals 83 and 84 connected to the electrodes 6 and 7 and voltage detection parts 91 and 92 connected to the current detection circuit board 34. The voltage detection part 91 is formed in the electrode part 76, and the voltage detection part 92 is formed in the electrode part 77.

[0084] As Figure 16 (a) shows, since the bridge part 70 is bent at a right angle, the shunt resistor 1 connected to the connection terminals 83 and 84 and the current detection circuit board 34 connected to the voltage detection parts 91 and 92 are perpendicular to each other. The voltage detection parts 91 and 92 and the pad for the voltage terminal (not shown) provided on the current detection circuit board 34 are connected by means such as soldering.

[0085] Figure 17 is a diagram showing a current detection circuit board mounted on a shunt resistor via two bridge parts. As Figure 17 shown, the shunt resistor 1 includes bridge parts 70A and 70B, and the current detection circuit board 34 is mounted on the shunt resistor 1 in a state of being held between the opposed bridge parts 70A and 70B. In this state, the current detection circuit board 34 and the shunt resistor 1 are perpendicular to each other.

[0086] As Figure 17As shown, the bridge portion 70A includes: a resistance portion 75A, electrode portions 76A and 77A, connection terminals 83A and 84A connected to the shunt resistor 1, and voltage detection portions 91A and 92A connected to the current detection circuit board 34. Similarly, the bridge portion 70B includes: a resistance portion 75B, electrode portions 76B and 77B, connection terminals 83B and 84B connected to the shunt resistor 1, and voltage detection portions 91B and 92B connected to the current detection circuit board 34. The voltage detection portions 91A, 91B, 92A, and 92B are connected to voltage terminal pads (not shown) provided on the circuit board 34 by means such as soldering.

[0087] Figure 18 FIG. is a diagram showing a current detection circuit board mounted on a shunt resistor via a bridge portion bent in a U shape. As Figure 18 shown, the bridge portion 70 is bent in a U shape, and the current detection circuit board 34 connected to the voltage detection portions 91 and 92 of the bridge portion 70 is disposed above the shunt resistor 1. The voltage detection portions 91 and 92 are connected to voltage terminal pads (not shown) provided on the current detection circuit board 34 by means such as soldering.

[0088] According to Figures 16 to 18 the embodiment shown, by means of bending the plate-shaped bridge portion 70 in the second direction (i.e., the direction perpendicular to the length direction of the resistor body 5) to mount the current detection circuit board 34, and means of arranging a plurality of bridge portions 70 to mount the current detection circuit board 34, the degree of freedom in the layout of the current detection circuit board 34 can be improved. In one embodiment, the plate-shaped bridge portion 70 may also be bent in the first direction (i.e., the length direction of the resistor body 5).

[0089] The above-described embodiment has been described for the purpose of enabling a person having ordinary knowledge in the technical field to which the present invention pertains to implement the present invention. Those skilled in the art can naturally obtain various modification examples of the above-described embodiment, and the technical idea of the present invention can also be applied to other embodiments. Therefore, the present invention is not limited to the described embodiment, and should be interpreted as following the broadest scope defined by the claims.

Claims

1. A shunt resistor for current detection, comprising: A base portion composed of a resistor body and a pair of electrodes connected to both ends of the resistor body, and arranged in the order of electrode, the resistor body, and electrode in the length direction of the shunt resistor; A bridge portion bridging the pair of electrodes and composed of a conductor; And A connection portion connecting the pair of electrodes and the bridge portion, The bridge portion has a resistance value higher than the resistance value of the base portion at the connection portion.

2. The shunt resistor according to claim 1, Wherein, The bridge portion has a size smaller than the size of the base portion.

3. The shunt resistor according to claim 1, Wherein, The connection portion is arranged along the joint portion of the pair of electrodes and the resistor body.

4. The shunt resistor according to claim 2, Wherein, The connection portion is arranged along the joint portion of the pair of electrodes and the resistor body.

5. The shunt resistor according to any one of claims 1 to 4, Wherein, The bridge portion is provided with voltage detection portions arranged on both end portions sides of the bridge portion.

6. The shunt resistor according to claim 5, Wherein, The bridge portion is provided with a slit portion arranged between the connection portion and the voltage detection portion.

7. The shunt resistor according to any one of claims 1 to 4, Wherein, The shunt resistor is provided with a voltage detection portion arranged adjacent to the connection portion.

8. The shunt resistor according to any one of claims 1 to 4, Wherein, The bridge portion has a plate shape and is bent in a direction perpendicular to the length direction of the resistor body.

9. The shunt resistor according to claim 5, Wherein, The bridge portion has a plate shape and is bent in a direction perpendicular to the length direction of the resistor body.

10. The shunt resistor according to claim 6, Wherein, The bridge portion has a plate shape and is bent in a direction perpendicular to the length direction of the resistor body.

11. The shunt resistor according to claim 7, Wherein, The bridge portion has a plate shape and is bent in a direction perpendicular to the length direction of the resistor body.

12. A current detection device, comprising: The shunt resistor according to any one of claims 1 to 11; and A current detection circuit board having a voltage signal wiring for transmitting a voltage signal from the shunt resistor, The bridge portion is provided with voltage detection portions arranged on both end portions sides of the bridge portion, The current detection circuit board is provided with voltage terminal pads connected to the voltage detection portions.

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