JP2019066499A - Resistor and current detector - Google Patents

Abstract

To provide a shunt resistor which allows a busbar and substrate to be easily fixed thereto with sufficient strength and requires only minimal processing on its electrodes, and to provide a current detector having the same.SOLUTION: A shunt resistor 10 used for current detection is provided, comprising through-holes 13 for fixing bolts 14 to be inserted. Each through-hole is provided with a fixing nut 15 used in combination with the fixing bolt. The fixing nut has a contact surface 15c to be brought into contact with an area surrounding an opening of the through-hole, and a press-fitting portion 15b to be brought into contact with an inner wall of the through-hole. The fixing nut is fixed to the shunt resistor by press-fitting the press fitting portion into the through-hole.SELECTED DRAWING: Figure 1C

Description

  The present invention relates to a shunt resistor and a current detection device using the shunt resistor.

  Conventionally, as a method of connecting a shunt resistor and a bus bar, there is known a method of forming a hole in an electrode portion of the shunt resistor and the bus bar and fixing the hole with a bolt and a nut. There is also known a method of forming an electrode portion of a shunt resistor in a bolt shape and fixing a bus bar to the electrode portion using a nut (see Patent Document 1).

  However, in the method using the bolt and the nut, the bolt or the nut may move freely, and the fixing operation may be complicated. In addition, when the hole in the electrode part is a female screw, the force is concentrated on the thread, but the copper material used for the electrode has low hardness, and in particular, when the electrode is thin, sufficient adhesion strength can be obtained. There is no such thing.

  In addition, the shunt resistor may be fixed to the circuit board on which the current detection circuit is mounted. For example, there is a method of soldering and fixing the fixing terminal previously formed on the circuit board and the electrode portion of the shunt resistor. However, in this method, there are problems such as the fixing position of the circuit board can not be determined and the fixing strength becomes insufficient.

Re-issued patent WO2011-068205

  The present invention has been made based on the above-mentioned circumstances, and can easily fix a bus bar, a circuit board or the like to a shunt resistor with sufficient strength, and requires only minimal processing of the electrode itself, and the shunt resistor An object of the present invention is to provide a current detection device including a shunt resistor.

  The shunt resistor according to the present invention is a shunt resistor used for current detection, and the shunt resistor includes a through hole for inserting a fixing bolt, and the through hole is used for the fixing bolt. A fixing nut to be combined with the fixing nut, the fixing nut including an abutting surface abutting on the periphery of the opening of the through hole, and a press-fit portion abutting on the inner surface of the through hole; The shunt resistor is characterized by being fixed by press-fitting the press-fit portion into the through hole. Since the screwing member is fixed to the electrode, the fixing operation of the bus bar and the like becomes easy. In addition, since the screwing member is a separate member from the electrode, the screwing member having strength can be selected, and the processing of the electrode itself can be minimized.

  Further, the current detection device of the present invention includes a shunt resistor used for current detection, a bus bar, and a circuit for current detection, and the current detection in which the shunt resistor and the bus bar are fastened by a fixing bolt and a fixing nut The shunt resistor includes a through hole for inserting the fixing bolt, and the fixing nut to be combined with the fixing bolt is disposed in the through hole. The nut includes an abutment surface abutting on the periphery of the opening of the through hole, and a press-fit portion abutting on the inner surface of the through hole, and the fixing nut and the shunt resistor Fixed by press-fitting.

It is a perspective view of the surface side of the electric current detection apparatus of 1st Example of this invention. It is a perspective view of the back side of the current sensing device of a 1st example of the present invention. The left side of the current detection device according to the first embodiment of the present invention is a cross-sectional view, and the right side is a front view. It is a disassembled perspective view of the electric current detection apparatus of 1st Example of this invention. It is a perspective view of the shunt resistor of 2nd Example of this invention. It is sectional drawing of the shunt resistor of 2nd Example of this invention. It is sectional drawing of the electric current detection apparatus of 3rd Example of this invention. It is a perspective view of the surface side of the electric current detection apparatus of 4th Example of this invention. It is a perspective view of the back side of the current sensing device of a 4th example of the present invention. It is a disassembled perspective view of the electric current detection apparatus of 4th Example of this invention. It is a perspective view of the stage which fixed the bus bar of a 4th example of the present invention. It is a perspective view of the surface side of the electric current detection apparatus of 5th Example of this invention. It is a perspective view of the back side of the current sensing device of a 5th example of the present invention. It is a perspective view of the surface side of the electric current detection apparatus of 6th Example of this invention. It is a perspective view of the back side of the current sensing device of a 6th example of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1A to 6B. In the drawings, the same or corresponding members or elements will be described with the same reference numerals.

  1A-1D show a current detection device according to a first embodiment of the present invention. The current sensing device includes a shunt resistor 10 with at least one pair of electrodes. The shunt resistor 10 is a metal resistor including a resistor 11 made of a resistance alloy such as Cu-Mn-Ni and a pair of plate-like electrodes 12 made of a metal such as Cu. The shunt resistor 10 is provided with holes 13 for fixing the substrate 20 to the electrodes 12 and 12, and both holes are provided with holes for fixedly connecting with a bus bar or the like. The resistor 11 and the electrode 12 are joined with end faces butted and welded by a method such as laser or electron beam. Detection terminals 16 and 16 are provided in the vicinity of a connection portion of the electrodes 12 and 12 with the resistor 11. The detection terminal 16 is a rod-like small piece made of metal such as Cu and fixed to the electrode 12 by welding or the like. The substrate 20 is made of, for example, a glass epoxy substrate, and is mounted with a current detection circuit including a current detection IC, a wiring pattern, a signal output terminal (all not shown), and the like.

  A screwing member (nut 15), which is a set of members separate from the electrode, is fixed to the electrode 12 of the shunt resistor. The bolt 14 and the nut 15 of the screwing member are respectively provided with a male screw 14a and a female screw 15a (see FIG. 1C). Then, a predetermined interposed member (in this example, the substrate 20 on which the current detection circuit is mounted) is disposed between one screwing member (bolt 14) and the other screwing member (nut 15), and screwing is performed. It is fixed.

  The substrate 20 has a wiring pattern connected to the detection terminal 16, and a voltage generated by the detection current flowing from the electrode 12 through the resistor 11 is taken out from the detection terminal 16 and signal-processed by the current detection IC. It is output as a detection voltage from the terminal. Note that, instead of the substrate 20, a bus bar for supplying current may be used as an intervening member to connect and fix using a screwing member that is combined with the electrode 12.

  The substrate 20 is provided with a hole 21 for inserting the bolt 14 and a hole 22 for inserting the detection terminal 16 (see FIG. 1D). Then, the substrate 20 is superimposed on the shunt resistor 10, the hole 21 of the substrate 20 is aligned with the hole 13 of the shunt resistor 10, the detection terminal 16 is inserted into the hole 22 of the substrate 20, and the holes 21 and 13 are front sided. Through the bolt 14 and screwed with a nut 15 from the back side. Thereby, the board | substrate 20 which is an intervening member is fixed to the shunt resistor 10 by the screwing member which becomes a group.

  The bolt 14 of the screwing member is provided with an external thread 14a. Further, the nut 15 of the screwing member is provided with a female screw portion 15 a, and is provided with a convex portion 15 b press-fit into the hole 13. The outer diameter of the convex portion (press-fit portion) 15 b is slightly larger than the inner diameter of the hole 13, and the nut 15 is fixed to the electrode 12 by press-fitting the convex portion (press-fit portion) 15 b of the nut 15 into the hole 13. The convex portion (press-fit portion) 15 b may be welded and fixed to the electrode 12. The material of the screwing member is copper, brass, stainless steel, titanium or the like. The same copper as the electrode 12 may be used, or another material may be used.

  The electrode 12 is provided with a hole 13, and the nut 15, which is a screwing member, is provided with a contact surface 15c which is in contact with the periphery of the opening of the hole 13. That is, the contact surface 15 c of the nut 15 is in contact with the electrode surface on the lower surface side of the electrode 12. And since the convex portion (press-fit portion) 15 b is formed around the opening of the nut 15, the outer periphery of the convex portion (press-fit portion) 15 b of the nut 15 which is a part of the screwing member It is in contact with the inner surface. The convex portion (press-fit portion) 15 b does not reach the opening opposite to the opening in which the nut 15 is disposed. And convex part (press fit portion) 15b is annular (refer to Drawing 1C and Drawing 1D).

  As a result, since the nut 15 is previously fixed to the hole 13 of the electrode 12, the male screw portion 14a of the bolt 14 is inserted into the hole 21 of the substrate 20 and the hole 13 of the electrode 12 and screwed onto the nut 15. Only, the substrate 20 can be easily fixed to the shunt resistor 10 with sufficient strength. And since the screwing member is a separate member from the electrode, the screwing member having strength can be selected. Further, the electrode 12 only needs to have holes 13 for bolt penetration, and the substrate 20 can be attached to the shunt resistor with a simple operation with minimum processing. The detection terminal 16 is formed on the upper surface side (one surface) of the electrode 12, and a screwing member (in this example, the nut 15) fixed in advance to the electrode 12 is different from the surface of the electrode 12 on which the detection terminal 16 is formed. , And is fixed to the lower surface side (other surface) of the electrode 12. Therefore, when the substrate 20 and the shunt resistor 10 are fixed by the bolt and the nut, both the substrate 20 and the electrode 12 connected to the detection terminal 16 are held between the bolt and the nut, so that stable fixing can be achieved. .

  Figures 2A-2B illustrate a shunt resistor according to a second embodiment of the present invention. In this embodiment, a hexagonal recess 13 a is formed around the hole 13 of the electrode 12. Therefore, the nut 15 having a hexagonal outer shape is fitted in the recess 13a to prevent the nut 15 from spinning. Unlike the first embodiment, the nut 15 is not provided with the convex portion 15b, but the nut 15 may be pressed into the concave portion 13a, welded after being disposed in the concave portion 13a, adhered by an adhesive, or the like. The numeral 15 is previously fixed to the electrode 12 to such an extent that it is not easily removed. The recess 13 a may be circular or the like in addition to the six-figure shape, and has a shape that allows the nut 15 to be positioned on the electrode 12.

  Thus, as in the first embodiment, since the nut 15 is fixed to the hole 13 of the electrode 12, the bolt 14 is inserted into the hole 21 of the substrate 20 and the hole 13 of the electrode 12 and screwed onto the nut 15. The substrate 20 can be easily attached to the shunt resistor 10 with sufficient strength.

  FIG. 3 shows a current detection device according to a third embodiment of the present invention. This embodiment is a modification of the second embodiment, and the hexagonal head of the bolt 14 which is one screwing member is fixed to the recess 13a provided in the electrode 12, and the other screw is fixed from the opposite side A nut 15, which is a member, is screwed and fixed to the male screw portion 14a of the bolt 14. The bolt 14 is previously fixed to the electrode 12 by press fitting, welding, adhesion or the like as in the other embodiments. Also in this case, as in the first and second embodiments, the substrate 20 can be easily attached to the shunt resistor 10 with sufficient strength.

  4A-4D show a current detection device according to a fourth embodiment of the present invention. In this embodiment, the substrate 20 on which the current detection circuit is mounted and the bus bar 23 are fixed to the shunt resistor 10 by screwing members 14 and 15 (see FIGS. 4A-4B). The electrode 12a has a step having a height substantially the same as the thickness of the bus bar 23 with respect to the starting portion A of the normal thickness. When the end portion of the bus bar 23 is accommodated in the step portion, the surface of the bus bar 23 and the surface of the raised portion A form substantially the same flat surface (see FIG. 4D).

  As in the first embodiment, the substrate 20 is provided with holes 21 for bolt insertion and holes 22 for detection terminal insertion. Holes 24 are provided in the bus bar 23 at positions corresponding to the holes 21 for bolt insertion when the bus bar 23 is inserted into the stepped portion of the electrode 12 a, and the holes 13 are provided in the corresponding electrode 12 a. Then, the bolt 14 is inserted through the hole 21 of the substrate 20, the hole 24 of the bus bar 23, and the hole 13 of the electrode 12a, and screwed and fixed to the nut 15 fixed on the opposite side. The nut 15 has a projection 15a and is press-fit into and fixed to the hole 13 of the electrode 12a as in the first embodiment (see FIG. 4C).

  According to the configuration, when the bus bar 23 is fixed, the surface of the bus bar 23 and the surface of the raised portion A become substantially flat, so the mounting of the substrate 20 is facilitated, the fixing direction of the bus bar is restricted, and the bus bar is The merit of being able to prevent the short generation | occurrence | production by the rotation and bus bars contacting etc. arises etc. arises. Then, since the substrate 20 on which the bus bar 23 and the current detection circuit are mounted on the shunt resistor 10 can be simultaneously fixed by the screwing members, the work of fixing these intervening members to the shunt resistor can be greatly simplified and sufficient. Bonding strength is obtained.

  5A-5B show a current detection device according to a fifth embodiment of the present invention. This embodiment is an example in which the detection wire 27 connected to the washer 26 is fixed to both electrodes 12 of the shunt resistor 10 using a pair of screwing members consisting of bolts 14 and nuts 15. The electrode 12 is provided with a hole 13 and a bolt 14 is inserted into the hole 13 from the electrode surface side via a washer 26 (intervening member) to which a detection wire 27 is connected, and screwed to a nut 15 fixed in advance on the electrode back side. And fixed. The nut 15 is provided with a convex portion press-fit into the hole 13, the electrode 12 is provided with a concave portion fitted to the outer shape of the nut 15, and the electrode 12 and the nut 15 are fixed in advance by welding or an adhesive. Keep it.

  6A-6B show a current detection device according to a sixth embodiment of the present invention. In this embodiment, in a current detection device including a shunt resistor having a pair of electrodes, one screwing member (nut 15) previously fixed to only one electrode 12 and the other screwing member ( It is an example which arrange | positions the predetermined | prescribed intervening member (board | substrate 20) between bolt 14), and it fixes by screwing. In the other electrode 12, one side of the substrate 20 is fixed using a locking portion 28. The other configuration is the same as that of the first embodiment.

  In this current detection device, a nut 15 is fixed to the back surface side of one electrode 12, one side of the substrate 20 is fixed to the locking portion 28 of the other electrode, and the bolt 14 is fixed to the hole 21 of the substrate and the hole 13 of the electrode. It can be manufactured by inserting (see FIG. 1C) and screwing to the nut 15. The substrate 20 can be easily attached to the shunt resistor 10 with sufficient strength even in the case of fixing the intervening member by the pair of screwing members on only one side of the electrode.

  Although one embodiment of the present invention has been described above, it goes without saying that the present invention is not limited to the above-described embodiment, and may be implemented in various different forms within the scope of the technical idea thereof.

  INDUSTRIAL APPLICABILITY The present invention can be suitably used for a current detection device that easily fixes a substrate, a bus bar, and the like with sufficient strength to a shunt resistor.

Claims (4)

A shunt resistor used for current detection,
The shunt resistor includes a through hole for inserting a fixing bolt.
In the through hole, a fixing nut to be combined with the fixing bolt is disposed;
The fixing nut includes an abutting surface that abuts on the periphery of the opening of the through hole, and a press-fit portion that abuts on an inner surface of the through hole.
A shunt resistor characterized in that the fixing nut and the shunt resistor are fixed by pressing the press-fit portion into the through hole.   The shunt resistor according to claim 1, wherein the press-fit portion does not reach an opening opposite to the opening in which the fixing nut is disposed.   The shunt resistor according to claim 1, wherein the press-fit portion is annular. A current detection device comprising a shunt resistor used for current detection, a bus bar, and a current detection circuit, wherein the shunt resistor and the bus bar are fastened by a fixing bolt and a fixing nut,
The shunt resistor has a through hole for inserting the fixing bolt.
In the through hole, the fixing nut to be combined with the fixing bolt is disposed;
The fixing nut includes an abutting surface that abuts on the periphery of the opening of the through hole, and a press-fit portion that abuts on an inner surface of the through hole.
The current detecting device, wherein the fixing nut and the shunt resistor are fixed by press-fitting the press-fit portion into the through hole.

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