Current detection device, method for manufacturing same, and resistance element unit

Abstract

This current detection device comprises: a circuit board; a resistance element unit that includes a resistor having a first surface and a second surface in the thickness direction; a mounting unit which is formed on the circuit board and to which the second-surface side of the resistor is affixed; a clip or a bus bar that constitutes a terminal member connected to the first-surface side of the resistor; and a detection line that is fixed to the terminal member and is used for detecting the voltage of the resistance element unit. The terminal member or the circuit board has a position display part that identifies the position at which the resistance element unit is mounted, the position display part serving as a reference for the position at which the detection line is fixed to the terminal member.

Description

Current detection device, manufacturing method thereof, and resistor element section

[0001] The present invention relates to a current detection device, a manufacturing method thereof, and a resistor element section.

[0002] JP2022-66642A discloses a shunt resistor provided with an electrode member having a slit formed at a contact portion that contacts a resistor.

[0003] In a current detection device including a resistor element section corresponding to the above-described shunt resistor, one surface of the resistor element section is fixed to a mounting portion of a circuit board, and terminal members such as clips and bus bars are fixed to the other surface, and a detection line for detecting the voltage of the resistor element section is fixed thereon. In such a configuration, due to variations in the dimensions of the resistor element section mounted on the circuit board, the resistance temperature coefficient (TCR) of the resistor element section changes significantly depending on the positional relationship between the fixing position of the detection line with respect to the terminal member and the mounting position of the resistor element section. The inventors have found this.

[0004] Therefore, the present invention has been made paying attention to the above-described problems, and an object thereof is to suppress changes in resistance characteristics caused by variations in the dimensions of the resistor element section.

[0005] According to a first aspect of the present invention, a current detection device includes a circuit board, a resistor element section including a resistor having a first surface and a second surface in the thickness direction, a mounting portion formed on the circuit board to which the second surface side of the resistor is fixed, a terminal member connected to the first surface side of the resistor, and a detection line fixed to the terminal member for detecting the voltage of the resistor element section. The terminal member or the circuit board has a position display portion that specifies the mounting position of the resistor element section and serves as a reference for the fixing position of the detection line with respect to the terminal member.

[0006] According to a second aspect of the present invention, a manufacturing method of the current detection device according to the first aspect includes a step of confirming the position display portion, a step of calculating the fixing position of the detection line using the position display portion as a reference position, and a step of fixing the detection line to the terminal member.

[0007] According to a third aspect of the present invention, the resistive element portion includes a resistor, and a terminal member for fixing a detection wire for detecting voltage is connected to the first surface side of the resistor and to the mounting portion of the circuit board, which is connected to the second surface side of the resistor. The mounting position of the resistive element portion is determined by the terminal member or the position indicator portion of the circuit board, which serves as a reference for the fixing position of the detection wire relative to the terminal member.

[0008] According to these embodiments, it becomes possible to accurately identify the mounting position of the resistive element by utilizing the position indicator provided on the terminal member or the circuit board, and furthermore, it becomes possible to appropriately define the fixing position of the detection line on the terminal member based on the position indicator.

[0009] Therefore, it becomes possible to adjust the positional relationship between the mounting position of the resistive element and the fixed position of the detection line to a positional relationship that is less likely to change the resistive characteristics. Consequently, it is possible to suppress changes in resistive characteristics caused by variations in the dimensions of the resistive element.

[0010] Figure 1 is a perspective view showing the external appearance of a current detection device according to the first embodiment. Figure 2 is an exploded view of the current detection device shown in Figure 1. Figure 3 is an exploded view of the resistive element section shown in Figure 1. Figure 4 is a diagram showing a region where TCR variation is easily suppressed. Figure 5A is a diagram illustrating the first simulation conditions for TCR. Figure 5B is a diagram illustrating the second simulation conditions for TCR. Figure 6 is a diagram showing the analysis results obtained under the conditions shown in Figures 5A and 5B. Figure 7 is a flowchart showing a method for mounting components on a circuit board. Figure 8 is a diagram illustrating the process of mounting components on a circuit board. Figure 9 is a flowchart showing a method for fixing a voltage detection wire on a clip. Figure 10 is a diagram illustrating the process of fixing a voltage detection wire on a clip. Figure 11 is a perspective view showing a modified resistive element section. Figure 12 is a perspective view showing a modified current detection device. Figure 13 is a top view showing a first modified position indicator section. Figure 14 is a top view showing a second modified position indicator section. Figure 15 is a top view showing a third modified position indicator section. Figure 16 is a perspective view showing the configuration of a current detection device according to the second embodiment. Figure 17 is a flowchart showing a method for manufacturing a current detection device. Figure 18 is a diagram illustrating the manufacturing method shown in Figure 18. Figure 19 is a perspective view showing the configuration of a current detection device according to the third embodiment. Figure 20 is a flowchart showing a method for manufacturing a current detection device. Figure 21 is a diagram illustrating the manufacturing method shown in Figure 20.

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Throughout this specification, the same or equivalent elements will be denoted by the same reference numerals.

[0012] Figure 1 is a perspective view showing the external appearance of the current detection device according to the first embodiment. Figure 2 is an exploded view of the current detection device shown in Figure 1. Figure 3 is an exploded view of the resistive element section of the current detection device shown in Figure 1.

[0013] The current detection device 1 is a device for detecting the current flowing through a circuit board 10 on which components are mounted. The current detection device 1 of the first embodiment consists of a circuit board 10, a resistor element section 20, a clip 30, and a voltage detection line 40.

[0014] The circuit board 10 is a substrate on which electronic components are mounted on pre-formed wiring. The circuit board 10 of the first embodiment has a pair of wiring patterns 11 and 12 and a pair of detection patterns 13 and 14.

[0015] The pair of wiring patterns 11 and 12 are wiring patterns for forming a current path. In the circuit board 10 of the first embodiment, for example, the current to be detected flows from wiring pattern 11 to wiring pattern 12. Depending on the magnitude of this current, various devices mounted on an automobile are controlled, for example.

[0016] The wiring pattern 11 functions as a mounting area on the circuit board 10 where the clip 30 is mounted, and the wiring pattern 12 functions as a mounting area on the circuit board 10 where the resistor element 20 is mounted.

[0017] The pair of detection patterns 13 and 14 are wiring patterns for detecting the voltage generated in the resistive element section 20. Detection pattern 13 is a wiring pattern drawn out from wiring pattern 12 between the pair of wiring patterns. On the other hand, detection pattern 14 is composed of a pad 141 to which one end of the voltage detection line 40 is connected, and a wiring pattern 142 drawn out from the pad 141.

[0018] Next, the configuration of the resistive element section 20 will be explained.

[0019] The resistive element section 20 is a columnar shunt resistor including a plate-shaped resistive element 21 having a predetermined thickness and width, and is formed, for example, as a rectangular parallelepiped. In this embodiment, the resistive element section 20 is formed in a rectangular columnar shape with one side of the surface being several [mm]. In addition to the thin plate-shaped resistive element 21, the resistive element section 20 also includes a pair of thin plate-shaped electrodes 22 and 23.

[0020] Examples of materials for the resistor 21 include low-resistance alloy materials such as Cu-Mn-Ni alloys and Ni-Cr alloys. Examples of materials for the electrodes 22 and 23 include highly conductive metals, and in this embodiment, copper (Cu) is used.

[0021] As shown in Figure 3, the resistor 21 has a first surface 21a and a second surface 21b, which is the surface opposite to the first surface 21a, in the thickness direction Dt. The electrode 22 is connected to the first surface 21a of the resistor 21, and the electrode 23 is connected to the second surface 21b of the resistor 21. That is, the electrode 22, the resistor 21, and the electrode 23 are stacked in this order in the thickness direction Dt of the resistive element portion 20.

[0022] The electrode 23 connected to the second surface 21b of the resistor 21 is connected to the wiring pattern 12. That is, the wiring pattern 12 formed on the circuit board 10 serves as the mounting area, and the second surface 21b side of the resistor 21 is fixed to it. On the other hand, the electrode 22 connected to the first surface 21a of the resistor 21 is connected to the clip 30.

[0023] The clip 30 functions as a terminal member connected to the first surface 21a side of the resistor 21. The clip 30 is connected to the resistive element 20 by welding such as pressure welding, solder, metal nanoparticles, or other connecting means. The metal nanoparticle connecting means refers to connection methods using silver paste with silver nanoparticles or copper paste with copper nanoparticles.

[0024] The clip 30 in this embodiment is connected to the resistive element portion 20 using solder. The clip 30 comprises a rectangular body portion 31 and leg portions 32 extending in the thickness direction Dt from a part of the body portion 31. The body portion 31 and the leg portions 32 are integrally formed with each other.

[0025] The clip 30 has a contact surface 30a between the clip 30 and the resistive element portion 20, and a surface 30b that is opposite to the contact surface 30a. A voltage detection wire 40 is fixed to the clip 30.

[0026] The voltage detection line 40 is a detection line for detecting the voltage of the resistive element 20, and in this embodiment, it is realized by a bonding wire. In this embodiment, the voltage detection line 40 is bonded to a fixed area of ​​surface 30b of the clip 30 that corresponds to the connection area to which the electrode 22 is connected. The fixed area of ​​surface 30b is subjected to a surface treatment such as NiP plating or Ni plating.

[0027] In such a current detection device 1, the clip 30 has a position indicator that serves as a reference for determining the positional relationship between the resistive element section 20 and the voltage detection line 40 via the clip 30, from the viewpoint of suppressing variations in TCR.

[0028] In this embodiment, the main body 31 of the clip 30 has a notch 33 formed near the resistive element 20, having opposing surfaces (101, 331). This notch 33 forms a reference surface 101 on the clip 30 that functions as a position indicator. The position indicator is a marker for identifying the mounting position of the resistive element 20 and also functions as a reference for the fixed position of the voltage detection line 40 relative to the clip 30.

[0029] The reference surface 101 is formed on the main body portion 31 of the clip 30 at a position corresponding to the side end portion 201 (see Figure 4) of the resistive element portion 20 that is closer to the extending direction De in which the clip 30 extends. The side end portion 201 of the resistive element portion 20 is a portion having a predetermined thickness that includes the side end surface 20a of the clip 30 that is closer to the extending direction De.

[0030] In this embodiment, the reference surface 101 of the notch 33, which is on the base end side Db opposite to the extending direction De, is formed to coincide with the side end surface 20a of the clip 30 in the resistive element portion 20 on the extending direction De side in the thickness direction Dt.

[0031] In other words, the reference surface 101 is formed on the clip 30 so as to coincide with the side end surface 20a, which is the edge of the side end 201 of the resistive element portion 20, in the thickness direction Dt. Therefore, the reference surface 101 of the clip 30 functions as a position indicator related to the position of the resistive element portion 20, which serves as a reference for the fixed position of the voltage detection line 40 on the clip 30.

[0032] In this way, by providing a reference surface 101 near the side end face 20a of the resistive element portion 20 of the clip 30, it becomes possible to appropriately adjust the positional relationship between the clip 30 and the resistive element portion 20 so that fluctuations in the TCR of the current detection device 1 are suppressed.

[0033] Next, the fixing position of the voltage detection wire 40 with respect to the surface 30b of the clip 30 will be explained with reference to Figure 4.

[0034] Figure 4 shows an example of a fluctuation suppression region 31c within the fixed region 31b of the voltage detection line 40 in the clip 30, in which fluctuations of the TCR of the current detection device 1 are suppressed.

[0035] The fluctuation suppression region 31c here is a region defined so that the TCR of the current detection device 1 is approximately 0 [ppm / K]. The fixed region 31b has a larger area than the resistive element portion 20, and in the vertical direction (width direction of the clip 30) in Figure 4(b), the width of the clip 30 is greater than that of the resistive element portion 20. Also, in the horizontal direction (length direction of the clip 30) in Figure 4(b), the end of the clip 30 in the base end direction Db extends beyond the resistive element portion 20.

[0036] In Figure 4, the direction Di in which the current flows in the current detection device 1 is shown by a dashed line. For the sake of ease of understanding the drawing, the detection pattern 13 drawn from the wiring pattern 12 will be omitted below for convenience.

[0037] Figure 4(a) shows a side view of the current detection device 1 as seen from a direction parallel to the circuit board 10, and Figure 4(b) shows a top view of the current detection device 1 as seen from a direction perpendicular to the circuit board 10.

[0038] As shown in Figure 4, in this embodiment, the clip 30 is mounted on the electrode 22 of the resistive element portion 20 such that the reference surface 101 provided on the clip 30 coincides with the side end surface 20a of the resistive element portion 20 in the thickness direction Dt.

[0039] In such a configuration, it is desirable to fix the voltage detection line 40 to the fluctuation suppression region 31c from the center of the fixed region 31b to a position separated from the side end face 20a by a predetermined distance with respect to the extending direction De of the clip 30. Thereby, the TCR of the current detection device 1 can be made closer to 0 [ppm / K].

[0040] Next, changes in the TCR of the current detection device 1 due to variations in the length dimension of the resistance element portion 20 will be described with reference to FIGS. 5A, 5BB, and FIG. 6.

[0041] FIGS. 5A and 5B are diagrams showing the positional relationship conditions between the resistance element portion 20 and the clip 30 according to the dimensional changes of the resistance element portion 20 when simulating the TCR of the current detection device 1.

[0042] In this simulation, the outer dimensions of the resistance element portion 20 are set to a length of 3.0 [mm] in the extending direction De × a depth of 3.5 [mm] × a thickness of 0.6 [mm], the thickness of the resistor 21 is set to 0.4 [mm], the thicknesses of the respective electrodes 22 and 23 are set to 0.1 [mm], and the specific resistance of the resistor 21 is set to 270 [μΩ·cm].

[0043] Furthermore, the thickness of each of the pair of wiring patterns 11 and 12 is set to 0.5 [mm], and the thickness of the solder for connecting the resistance element portion 20 between the clip 30 and the wiring pattern 12 is set to 0.05 [mm]. And the fixed position of the voltage detection line 40 disposed on the surface 30b of the clip 30 is set to a position shifted by 0.9 [mm] in the extending direction De from the center Pc of the resistance element portion 20 in the extending direction De of the main body portion 31.

[0044] FIG. 5A is a diagram for explaining the first simulation condition. In the first simulation condition, with the position of the side end face 20b opposite to the side end face 20a in the extending direction De fixed as the dimension of the resistance element portion 20 changes, the position of the side end face 20a is moved 0.1 [mm] at a time in the base end direction Db.

[0045] FIG. 5B is a diagram for explaining the second simulation condition. In the second simulation condition, with the position of the side end face 20a fixed as the dimension of the resistance element portion 2 dimension changes, the position of the side end face 20b in the base end direction Db is moved 0.1 [mm] at a time in the extending direction De.

[0046] FIG. 6 is a diagram showing the results obtained under the first simulation conditions shown in FIG. 5A and the second simulation conditions shown in FIG. 5B.

[0047] As shown in FIG. 6, with the position of the voltage detection line 40 fixed, as the position of the side end face 20a approaches the voltage detection line 40 as shown in FIG. 5A, the change amount of the TCR increases significantly. The rate of increase is about 30 [ppm] for a change of 0.1 [mm].

[0048] On the other hand, as the position of the side end face 20b farther from the voltage detection line 40 approaches the voltage detection line 40 as shown in FIG. 5B, the change amount of the TCR similarly increases. The rate of increase is about 3 [ppm] for a change of 0.1 [mm], which is about one-tenth compared to the first simulation conditions.

[0049] Thus, the inventors have found that for the position of the side end face 20a closer to the fixed position of the voltage detection line 40 in the fluctuation suppression region 31c of the clip 30, even when the position of the side end face 20a is deviated on the order of 0.1 [mm], the TCR changes significantly.

[0050] As a countermeasure, in this embodiment, a notch 33 having a reference plane 101 is formed in the clip 30 as a position display portion that defines the position of the side end face 20a of the resistance element portion 20 with respect to the clip 30 so that the individual difference in the TCR of the current detection device 1 is suppressed.

[0051] [[ID=...]] Next, a method for manufacturing the current detection device 1 will be described.

[0052] First, a method for mounting the resistance element portion 20 and the clip 30 on the circuit board 10 will be described with reference to FIGS. 7 and FIG. 8. ...

[0053] FIG. 7 is a flowchart showing a mounting method for sequentially mounting the resistance element portion 20 and the clip...

[0054] In step S1 shown in Figure 7, a clip 30 is prepared with a reference surface 101 formed as a position indicator, as shown in Figure 8(a).

[0055] In step S2, the resistive element 20 is mounted on the circuit board 10. In this embodiment, the electrodes 23 of the resistive element 20 are connected to the wiring pattern 12 of the circuit board 10 by solder. That is, the second surface 21b side of the resistor 21 is fixed to the wiring pattern 12 formed on the circuit board 10.

[0056] In step S3, the position of the side end face 20a of the resistive element 20 is confirmed. In this embodiment, as shown in Figure 8(b), a camera 91 installed above the resistive element 20 generates image data showing the top surface of the resistive element 20. This image data is analyzed by a control device of the production line (not shown), and the coordinate position of the side end face 20a of the resistive element 20 is identified in coordinate data representing the production line, which is expressed in two-dimensional or three-dimensional coordinates. Alternatively, the position of the side end face 20a of the resistive element 20 may be confirmed visually by an operator.

[0057] In step S4, the reference surface 101 of the clip 30 is aligned with the side end face 20a of the resistive element portion 20. In this embodiment, as shown in Figure 8(c), solder is applied to the wiring pattern 11 and the electrodes 22 of the resistive element portion 20, and the clip 30 is attracted by the suction nozzle 92. The position of the clip 30 is then adjusted so that the reference surface 101 of the clip 30 coincides with the side end face 20a of the resistive element portion 20, which was confirmed in step S3, in the thickness direction Dt.

[0058] In step S5, the clip 30 is mounted on the resistive element portion 20. In this embodiment, as shown in Figure 8(d), the clip 30 is fixed to the wiring pattern 11 and the electrodes 22 of the resistive element portion 20 such that the reference surface 101 of the clip 30 coincides with the side end surface 20a of the resistive element portion 20.

[0059] When step S5 is completed, the method for mounting the resistor element 20 and clip 30 to the circuit board 10 is finished.

[0060] Next, a method for fixing the voltage detection wire 40 to the clip 30 will be explained with reference to Figures 9 and 10.

[0061] Figure 9 is a flowchart showing a method for fixing the voltage detection wire 40 to the clip 30. Figure 10 is a diagram illustrating how the voltage detection wire 40 is fixed to the clip 30.

[0062] In step S11 shown in Figure 9, the voltage detection wire 40 is prepared. In this embodiment, a bonding wire is prepared as the voltage detection wire.

[0063] In step S12, the position of the reference surface 101, which functions as a position indicator for the clip 30, is confirmed. In other words, step S12 is a confirmation step to confirm the position of the position indicator.

[0064] In this embodiment, as shown in Figure 10(a), similar to step S3, the coordinate position of the reference plane 101 of the clip 30 is determined in a control device (not shown) based on image data from the camera 91 or input data from the operator.

[0065] In step S13, the fixed position 41 of the voltage detection line 40 is determined based on the position of the reference surface 101 on the clip 30 obtained in step S12. In other words, step S13 is a calculation step in which the fixed position 41 of the voltage detection line 40 is calculated using the position display unit as the reference position.

[0066] In this embodiment, the fixed position 41 is determined to be a position located a predetermined distance away from the side end face 20a of the resistive element portion 20 in the base end direction Db, as shown in Figure 10(b), and is located at the center of the short side of the clip 30. In Figure 10(b), the offset from the reference plane 101 and the fixed position 41 are shown by dashed lines. The predetermined distance is determined appropriately according to the shape and material of the resistive element portion 20 and the clip 30.

[0067] In step S14, the voltage detection wire 40 is fixed to the fixing position 41 of the clip 30 determined in step S13. That is, step S14 is a fixing step in which the voltage detection wire 40 is fixed to the clip 30 that constitutes the terminal member. In this embodiment, as shown in Figure 10(c), the wire used as the voltage detection wire 40 is bonded at the fixing position 41.

[0068] When step S14 is completed, the method for fixing the voltage detection wire 40 to the clip 30 is finished.

[0069] Next, a brief explanation of modified components of the current detection device 1 will be given with reference to Figures 11 and 12.

[0070] Figure 11 is a perspective view showing the external appearance of a current detection device 1A relating to a modified example of the resistive element section 20.

[0071] The current detection device 2 has the same basic configuration as the current detection device 1 shown in Figures 1 and 2, and instead of the resistive element section 20, it is equipped with a resistive element section 200 in which the electrode 22 is omitted. Thus, it is also possible to mount the clip 30 having the reference surface 101 of this embodiment on the first surface 21a of the resistor 21 of the resistive element section 200.

[0072] Instead of the resistive element section 200 to which the clip 30 is connected, a resistive element section in which electrode 23 of the electrodes 22 and 23 of the resistive element section 20 shown in Figure 1 is omitted, or a resistive element section in which both electrodes 22 and 23 are omitted, may be used.

[0073] Thus, the resistive element portion mounted on the circuit board 10 only needs to include a resistor 21 having a first surface 21a and a second surface 21b in the thickness direction Dt.

[0074] Figure 12 is a perspective view showing the external appearance of a current detection device 1B related to a modified example of the terminal member.

[0075] The current detection device 2 has the same basic configuration as the current detection device 1 shown in Figure 1, but instead of clips 30, it is equipped with busbars 60. Other components are the same as those of the current detection device 1, so they are given the same reference numerals and their explanation is omitted here.

[0076] In the current detection device 2, the busbar 60 functions as a terminal member connected to the first surface 21a side of the resistor 21, and the busbar 60 has a notch 63, similar to the notch 33 of the clip 30. The notch 63 identifies the mounting position of the resistive element and forms a reference surface 101, which serves as a position indicator for the fixed position of the voltage detection line 40 relative to the busbar 60.

[0077] The reference surface 101 of the notch 63 is used to ensure that the reference surface 101 of the busbar 60 coincides with the side end face 20a of the resistive element 20 in the thickness direction Dt. The busbar 60 is connected to the electrodes 22 of the resistive element 20 and to the wiring pattern 11. Furthermore, the voltage detection line 40 is fixed to a fixed area on the surface 60b of the busbar 60, with the reference surface 101 of the notch 63 as the reference.

[0078] In this way, the busbar 60 is fixed to the first surface 21a side of the resistor 21 of the resistor element 20 mounted on the circuit board 10 so as to suppress variations in the TCR of the current detection device 2.

[0079] Next, a brief explanation of a modified version of the position indicator unit will be given with reference to Figures 13 to 15.

[0080] Figure 13 is a top view showing a first modified example of the clip 30. The clip 301 according to the first modified example has a through hole 34 that extends in a direction perpendicular to the extending direction De of the clip 301.

[0081] The through-hole 34 is formed by a reference surface 102 that functions as a position indicator to identify the mounting position of the resistive element portion 20.

[0082] By utilizing the reference surface 102 of the clip 301, it becomes possible to mount the clip 301 on the resistive element portion 20 and the wiring pattern 11 such that the reference surface 102 and the side end surface 20a of the resistive element portion 20 coincide with each other in the thickness direction Dt.

[0083] Therefore, the reference surface 102 is formed on the clip 301 so as to coincide with the side end surface 20a, which is the edge of the side end 201 of the resistive element portion 20, in the thickness direction Dt. The fixing position of the voltage detection line 40 with respect to the clip 301 is determined with reference to the reference surface 102.

[0084] This allows the positional relationship between the mounting position of the resistive element 20 below the clip 301 and the fixing position of the voltage detection line 40 relative to the clip 301 to be adjusted to a predetermined positional relationship that suppresses variations in the TCR of the current detection device 1.

[0085] Figure 14 is a top view showing a second modified example of the clip 30. The clip 301A according to the second modified example has a through hole 34A formed at a different position from the through hole 34 shown in Figure 13.

[0086] The through-hole 34A is formed in the portion of the clip 301A where the clip 301A and the resistive element portion 20 come into contact. The through-hole 34A is formed by a reference surface 102A that functions as a position indicator to identify the mounting position of the resistive element portion 20.

[0087] The reference surface 102A is formed in the thickness direction Dt at the position of the clip 302A corresponding to the side end 201 of the resistive element portion 20. This allows the side end 201 of the resistive element portion 20 to be identified through the through hole 34A of the clip 301A, and the fixing position of the voltage detection line 40 relative to the clip 301A is determined with reference to the reference surface 102A that defines the through hole 34A.

[0088] Therefore, the positional relationship between the mounting position of the resistive element 20 below the clip 301 and the fixing position of the voltage detection line 40 relative to the clip 301 can be adjusted to a predetermined positional relationship that suppresses variations in the TCR of the current detection device 1.

[0089] Figure 15 is a top view showing a third modified example of the clip 30. The clip 302 according to the third modified example has a notch 33A. The notch 33A is formed by a reference surface 103 that functions as a position indicator to identify the mounting position of the resistive element portion 20 below the clip 302.

[0090] As shown in Figure 15, the reference surface 103 is formed such that the position of the side end 201 of the resistive element portion 20 fits within the gap of the notch 33A. By forming the reference surface 103 on the clip 302 in this way, the reference surface 102 is formed at the position of the clip 302 corresponding to the side end 201 of the resistive element portion 20 in the thickness direction Dt, similar to the first embodiment. The fixing position of the voltage detection line 40 with respect to the clip 302 is determined with respect to the reference surface 103.

[0091] This allows the corner of the resistive element 20 to be seen through the notch 33A of the clip 302, making it possible to determine the positional relationship between the resistive element 20 and the clip 302. It is also possible to check whether the resistive element 20 is mounted at an angle relative to the wiring pattern 12. In the case of a twisted state where the resistive element 20 is mounted at an angle relative to the wiring pattern 12, the angle of the clip 302 can be adjusted to match the twist of the resistive element 20 so that the positional relationship between the resistive element 20 and the clip 302 is appropriate.

[0092] Therefore, the positional relationship between the mounting position of the resistive element 20 below the clip 302 and the fixing position of the voltage detection line 40 relative to the clip 302 can be adjusted to a predetermined positional relationship that suppresses variations in the TCR of the current detection device 1.

[0093] Next, the position indicator unit according to the second embodiment will be described with reference to Figures 16 to 18.

[0094] Figure 16 is a perspective view showing the configuration of the current detection device 2 according to the second embodiment.

[0095] The current detection device 2 includes a clip 303 having a reference position 110, instead of the clip 30 having a reference surface 101 that functions as a position indicator for the current detection device 1 shown in Figures 1 and 2.

[0096] Note that the other components are the same as those of the current detection device 1, and are denoted by the same reference numerals as those shown in Figures 1 and 2, and their explanation here is omitted.

[0097] In this embodiment, the reference position 110 is provided on the clip 303. The reference position 110 corresponds to the position indicator section formed by the reference surface 101 of the clip 30 shown in Figures 1 and 2.

[0098] As described above, in this embodiment, a reference position 110 is provided on the clip 303 as a position indicator. Even in this case, it is possible to accurately determine the mounting position of the resistive element 20 below the clip 303 by using the reference position 110 on the clip 303, and then appropriately define the fixed position of the voltage detection line 40 on the clip 303 with respect to the reference position 110.

[0099] Figure 17 is a flowchart showing a method for manufacturing the current detection device 1 according to the second embodiment. Figure 18 is a diagram illustrating the manufacturing process of the current detection device 1 according to the second embodiment.

[0100] In step S21 shown in Figure 17, the resistive element 20 is mounted on the circuit board 10. In this embodiment, as shown in Figure 18(a), one electrode 23 of the resistive element 20 is fixed to the wiring pattern 12 of the circuit board 10 by solder.

[0101] In step S22, the clip 303 is mounted on the resistive element portion 20. In this embodiment, as shown in Figure 18(b), the clip 303 is fixed to the wiring pattern 11 and the other electrode 22 of the resistive element portion 20 by solder.

[0102] In step S23, the position of the resistive element 20 is confirmed. In this embodiment, as shown in Figure 18(c), a camera 91 installed near the resistive element 20 generates image data showing the position of one corner 20c and one side 20d of the resistive element 20. The generated image data is analyzed by a control device of the production line (not shown), and the mounting position of the resistive element 20 is determined based on the analysis results of the corner 20c and side 20d of the resistive element 20.

[0103] In order to determine the position of the resistive element portion 20, at least two pieces of positional information are required. Therefore, in this embodiment, image data showing the positions of each corner and side of the resistive element portion 20 was acquired. However, this is not limited to this, and for example, image data showing at least two corners or two sides of the resistive element portion 20 may be acquired.

[0104] Based on the result of determining the position of the resistive element 20, the coordinate position of the side end face 20a of the resistive element 20 is specified in coordinate data representing the production line, which is expressed in two-dimensional or three-dimensional coordinates. Alternatively, the position of the side end face 20a of the resistive element 20 may be confirmed visually by an operator.

[0105] In step S24, the reference position 110 is printed on the clip 303. In this embodiment, based on the determination result of identifying the mounting position of the resistive element 20 in step S23, the reference position 110, which functions as a position indicator, is engraved, for example, by a laser. That is, the reference position 110 has the function of identifying the mounting position of the resistive element 20.

[0106] Furthermore, the reference position 110, like the reference surface 101 shown in Figure 10, is also used as a reference for the fixed position of the voltage detection line 40 relative to the clip 303. For this reason, the reference position 110 provided on the clip 303 identifies the mounting position of the resistive element 20 and functions as a position indicator that serves as a reference for the fixed position of the voltage detection line 40 relative to the clip 303.

[0107] Next, the position indicator unit according to the third embodiment will be described with reference to Figures 19 to 21.

[0108] Figure 19 is a perspective view showing the configuration of the current detection device 3 according to the third embodiment.

[0109] The current detection device 3 includes a clip 304 that does not have a reference surface 101, instead of the reference surface 101 of the clip 30 that functions as a position indicator for the current detection device 1 shown in Figures 1 and 2, and a reference position 120 provided on the circuit board 10.

[0110] Note that the other components are the same as those of the current detection device 1, and are denoted by the same reference numerals as those shown in Figures 1 to 4, and their explanation here is omitted.

[0111] In this embodiment, the reference position 120 is provided around the wiring pattern 12 on the circuit board 10. The reference position 120 corresponds to the position indicator unit which is composed of the reference surface 101 of the clip 30 in the current detection device 1 shown in Figures 1 and 2.

[0112] As described above, in this embodiment, a reference position 120 is provided on the circuit board 10 as a position indicator. Even in this case, it is possible to accurately determine the mounting position of the resistive element 20 under the clip 304 by using the reference position 120 on the circuit board 10, and then appropriately define the fixed position of the voltage detection line 40 on the clip 304 with respect to the reference position 120.

[0113] Figure 20 is a flowchart illustrating the manufacturing method of the current detection device 3. Figure 21 is a diagram illustrating the manufacturing process of the current detection device 3.

[0114] In step S31 shown in Figure 20, the resistor element 20 is mounted on the circuit board 10 in accordance with the reference position 120, which functions as a position indicator provided on the circuit board 10.

[0115] In this embodiment, a control device (not shown) determines the coordinate position of a reference position 120 formed around the wiring pattern 12 on the circuit board 10 based on image data from the camera 91 or input data from the operator. Thus, the reference position 120 has the function of identifying the mounting position of the resistor element 20.

[0116] Then, as shown in Figure 21(a), according to the instructions of the control device, one electrode 23 of the resistive element 20 is mounted on the wiring pattern 12 of the circuit board 10 in accordance with the reference position 120 of the circuit board 10. In other words, the reference position 120 in this embodiment has the function of specifying the mounting position of the resistive element 20 and defining the resistive element 20 at the specified mounting position.

[0117] In step S32, the clip 304 is mounted on the resistive element portion 20. In this embodiment, as shown in Figure 21(b), the clip 304 is fixed to the wiring pattern 11 and the other electrode 22 of the resistive element portion 20 by solder.

[0118] In step S33, the voltage detection line 40 is fixed with reference to the reference position 120 of the circuit board 10. That is, the reference position 120 is also used as the reference for the fixing position of the voltage detection line 40 on the clip 30.

[0119] In this embodiment, the fixed position 42 of the voltage detection line 40 is determined based on the reference position 120 on the circuit board 10 obtained in step S31. The fixed position 42 is determined to be a position separated by a predetermined distance in the base end direction Db from the side end face 20a of the resistive element portion 20, and is located at the center of the short side of the clip 304, similar to Figure 10(b).

[0120] The predetermined distance mentioned above is determined appropriately according to the shape and material of the resistive element 20 and the clip 304. In this embodiment, as shown in Figure 21(c), the wire used as the voltage detection line 40 is bonded at a fixed position 42 determined by a control device (not shown).

[0121] Thus, the reference position 120 provided on the circuit board 10 identifies the mounting position of the resistive element 20 and functions as a position indicator that serves as a reference for the fixing position of the voltage detection line 40 relative to the clip 304.

[0122] In this embodiment, the reference position 120 is formed near the wiring pattern 12 on the circuit board 10, but this is not the only option. Any location that allows for the identification of the position of the resistive element 20 may be used as the reference position 120, such as a corner of the wiring pattern 12 on the circuit board 10 or a specific location such as a silkscreen print.

[0123] Next, the effects and advantages of the above embodiment will be described.

[0124] In the above embodiment, the current detection device 1 comprises a circuit board 10, a resistor element portion 20 or 200 composed of a resistor 21 having a first surface 21a and a second surface 21b in the thickness direction Dt, and a wiring pattern 12 formed on the circuit board 10, which constitutes a mounting portion to which the second surface 21b side of the resistor 21 is fixed.

[0125] Furthermore, the current detection device 1 includes a terminal member connected to the first surface 21a side of the resistor 21, and a voltage detection line 40 fixed to the terminal member for detecting the voltage of the resistive element portion 20. The terminal member is realized, for example, by the clips 30, 301, 301A, 302, 303, or 304 of the above embodiment.

[0126] The clips 30, 301, 301A, or 302 have reference surfaces 101, 102, 102A, or 103 that identify the mounting position of the resistive element 20 and serve as a reference for the fixed position of the voltage detection line 40 relative to the clips 30, 301, 301A, or 302.

[0127] Furthermore, the current detection device 1B of the above embodiment is equipped with a busbar 60 instead of the clips 30, 301, 301A, 302, 303, or 304 as terminal members. The busbar 60 has a reference surface 101 which identifies the mounting position of the resistive element section 20 or 200 and serves as a reference position indicator for the fixed position of the voltage detection line 40 relative to the busbar 60.

[0128] Furthermore, in the second and third embodiments, the current detection devices 2 and 3 are equipped with a reference position 110 or 120 as a position indicator, instead of the reference surfaces 101, 102, 102A, or 103.

[0129] Thus, the reference surfaces 101, 102, 102A, or 103, or the reference position 110 or 120, function as position indicators related to the position of the resistive element portion 20 or 200, which serve as the reference for the fixed position of the voltage detection line 40 on the terminal member.

[0130] Furthermore, in the above embodiment, the resistive element section 20 includes a resistor 21, and a terminal member for fixing a voltage detection line 40 for detecting voltage is connected to the first surface 21a side of the resistor 21, and the wiring pattern 12 constituting the mounting section of the circuit board 10 is connected to the second surface 21b side of the resistor 21. The terminal member is realized, for example, by the clips 30, 301, 301A, 302, 303 or 304 of the above embodiment or by a busbar 60.

[0131] The mounting position of the resistive element 20 or 200 is determined by the clips 30, 301, 302, 302A, which serve as a reference for the fixing position of the voltage detection line 40 with respect to the terminal member, or the reference surfaces 101, 102, 102A, or 103 of the busbar 60, or the reference position 110 or 120 of the circuit board 10.

[0132] With these configurations, it becomes possible to accurately identify the mounting position of the resistor element 20 or 200 by utilizing the position indicator provided on the terminal member or circuit board 10. In addition, it becomes possible to appropriately define the fixed position of the voltage detection line 40 on the terminal member based on the position indicator.

[0133] Therefore, the positional relationship between the mounting position of the resistive element 20 and the fixed position of the voltage detection line 40 can be adjusted to a positional relationship that is less likely to change the resistive characteristics. Consequently, changes in resistive characteristics caused by variations in the dimensions of the resistive element 20 or 200 can be suppressed.

[0134] Furthermore, in the above embodiment, the position indicator is formed on the clip 30, 301, 301A, or 302, or the bus bar 60, at a position corresponding to the side end 201 of the resistive element portion 20 or 200 that is closer to the extending direction De on which the clip 30, 301, 301A, 302, or the bus bar 60 extends.

[0135] As shown in Figure 6, misalignment of the side end 201 of the resistive element portion 20 or 200 closer to the extension direction De has a significant impact on the change in TCR. To address this, according to this embodiment, for example, as shown in Figure 15, by specifying the position of the side end 201 of the resistive element portion 20 or 200, variations in TCR can be suppressed compared to specifying the position of the side end opposite to the side end 201 of the resistive element portion 20 or 200 using the position display unit.

[0136] Furthermore, the current detection device 1 or 1B has a structure in which terminal members such as clips 30 or busbars 60 are interposed between the resistive element 20 and the voltage detection line 40. For this reason, in order to ensure current detection accuracy, it is necessary to maintain the positional accuracy of the resistive element 20 and the terminal members connected thereto.

[0137] However, when the terminal member is fixed onto the resistive element 20 after the resistive element 20 is mounted on the circuit board 10, variations in the mounting position of the resistive element 20 or 200 and variations in the mounting position of the terminal member will occur. In addition, the resistive element 20 or 200 may be hidden by the terminal member, making it impossible to determine the mounting position of the resistive element 20 or 200, and thus difficult to determine the fixing position of the voltage detection line 40. As a result, it is conceivable that the variation in TCR will increase for each current detection device 1, 1A, 1B, 2, or 3.

[0138] In contrast, with the above configuration, the mounting position of the resistive element 20 or 200 below the terminal member can be identified using the position indicator, and the fixed position of the voltage detection line 40 on the terminal member can be defined using this position indicator as a reference position. This makes it possible to adjust the positional relationship between the fixed position of the voltage detection line 40 and the mounting position of the resistive element 20 or 200 to a positional relationship that suppresses TCR variations.

[0139] Therefore, variations in resistance characteristics caused by the presence of a terminal member interposed between the fixed position of the voltage detection line 40 and the mounting position of the resistive element section 20 or 200 can be suppressed.

[0140] Furthermore, in the above embodiment, the resistive element portion 20 or 200 is rectangular columnar in shape. The reference surfaces 101, 102, 102A, or 103, which serve as position indicators, are formed on the clips 30, 301, 301A, 302, or busbars 60 so as to coincide with the side end surface 20a, which is the edge of the side end portion 201 of the resistive element portion 20 or 200, in the thickness direction Dt.

[0141] Regarding the change in TCR, as shown in Figure 6, the misalignment of the side end face 20a of the side end 201 of the resistive element portion 20 or 200 contributes significantly. Therefore, by accurately identifying the side end face 20a of the resistive element portion 20 or 200 using the reference surfaces 101, 102, 102A, or 103 of the clips 30, 301, 301A, 302 or the busbar 60, the variation in TCR can be reduced with greater accuracy compared to identifying the position of the side end 201.

[0142] Furthermore, according to the first modified example of the position indicator, as shown in Figure 13, the current detection device 1 is formed in the clip 301 and has a through hole 34 that extends in a direction perpendicular to the extending direction De of the clip 301. The reference surface 102 or 102A, which functions as a position indicator to identify the side end face 20a of the resistive element portion 20 in the thickness direction Dt, is formed by the through hole 34 or 34A.

[0143] With this configuration, the through-hole 34 or 34A prevents the voltage detection line 40 from being fixed in a region where the TCR is particularly prone to change. This makes it possible to avoid excessive changes in the TCR and to position the voltage detection line 40 at an appropriate fixing position that suppresses variations in the TCR.

[0144] Furthermore, the manufacturing method of the current detection device 1 in the first embodiment includes the steps of: confirming the reference surface 101 of the clip 30 which functions as a position indicator (S12); calculating the fixed position of the voltage detection line 40 using the reference surface 101 as the reference position (S13); and fixing the voltage detection line 40 to the clip 30 which serves as a terminal member (S14).

[0145] With this configuration, the mounting position of the resistive element portion 20 or 200 is accurately determined using the reference surface 101 of the clip 30, and the fixing position of the voltage detection line 40 is appropriately fixed to the clip 30 with respect to the reference surface 101.

[0146] This makes it possible to adjust the positional relationship between the mounting position of the resistive element section 20 or 200 and the fixed position of the voltage detection line 40 to a positional relationship that minimizes TCR variations, thereby suppressing changes in resistance characteristics caused by variations in the dimensions of the resistive element section 20 or 200.

[0147] Although this embodiment has been described above, the above embodiment is merely one example of how the present invention can be applied, and it is not intended to limit the technical scope of the present invention to the specific configuration of the above embodiment.

[0148] This application claims priority under Japanese Patent Application No. 2025-7156, filed with the Japan Patent Office on 17 January 2025, and all contents of that application are incorporated herein by reference.

[0149] 1, 1A, 1B, 2, 3 Current detection device 10 Circuit board 12 Wiring pattern (mounting part) 20, 200 Resistor element part 20a Side end face (edge ​​of side end face) 21 Resistor 21a First surface 21b Second surface 30, 301, 302, 302A, 303, 304 Clip (terminal member) 34, 34A Through hole 40 Voltage detection line (detection line) 60 Bus bar (terminal member) 101, 102, 102A, 103 Reference surface (position display part) 110, 120 Reference position (position display part) 201 Side end (side end from the extension direction) Dt Thickness direction De Extension direction S12-S14 (Confirmation process, calculation process, fixing process)

Claims

1. A current detection device comprising: a circuit board; a resistive element portion including a resistor having a first surface and a second surface in the thickness direction; a mounting portion formed on the circuit board to which the second surface side of the resistor is fixed; a terminal member connected to the first surface side of the resistor; and a detection line fixed to the terminal member for detecting the voltage of the resistive element portion, wherein the terminal member or the circuit board has a position indicator portion that identifies the mounting position of the resistive element portion and serves as a reference for the fixing position of the detection line with respect to the terminal member.

2. A current detection device according to claim 1, wherein the position indicator is formed on the terminal member at a position corresponding to the side end of the resistive element portion that is closer to the extending direction of the terminal member.

3. A current detection device according to claim 2, wherein the resistive element portion is rectangular in shape, and the position indicator portion is formed on the terminal member such that it coincides with the edge of the side end of the resistive element portion in the thickness direction.

4. A current detection device according to claim 3, wherein the terminal member has a through hole formed therein that extends in a direction perpendicular to the extending direction of the terminal member, and the position indicator is formed by the through hole.

5. A method for manufacturing a current detection device according to any one of claims 1 to 4, comprising: a confirmation step of confirming the position indicator unit; a calculation step of calculating the fixing position of the detection line using the position indicator unit as a reference position; and a fixing step of fixing the detection line to the terminal member.

6. A resistive element portion including a resistor, wherein a terminal member for fixing a detection line for detecting voltage is connected to the first surface side of the resistor, and the second surface side of the resistor is connected to the mounting portion of a circuit board, wherein the mounting position of the resistive element portion is determined by the terminal member or the position indicator portion of the circuit board, which serves as a reference for the fixing position of the detection line with respect to the terminal member.

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