JP2005188945A - Voltage-drop type current measuring device - Google Patents
Voltage-drop type current measuring device Download PDFInfo
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Abstract
Description
本発明は、電圧降下式電流計測装置及びそれに関連する技術に関する。 The present invention relates to a voltage drop type current measuring device and a technology related thereto.
例えば自動車等に搭載されて様々な負荷を駆動するに際して、電流センサで電流を計測し、発電機の制御パラメータ等に使用されている。 For example, when driving various loads mounted on an automobile or the like, the current is measured by a current sensor and used as a control parameter for a generator.
この場合に使用される電流センサとしては、ホール素子を用いたものもあるが、大電流を流す導体の大きさに準じて部品サイズが比較的大きくなり、このため小型化の要請に合致しない場合がある。そこで、電流経路内にシャント抵抗を配置し、このシャント抵抗に流れる電流を計測することが行われている。 Some current sensors used in this case use Hall elements, but the component size is relatively large according to the size of the conductor through which a large current flows, and this does not meet the requirements for miniaturization. There is. Therefore, a shunt resistor is arranged in the current path, and a current flowing through the shunt resistor is measured.
しかしながら、従来のシャント抵抗を用いた電流センサでは、所定の回路基板上にシャント抵抗を設ける構成が採用される場合が多い。このような構成では、シャント抵抗を専用部品として必要とする分だけ、部品点数が嵩み、装置構成の大型化等を招くとともに、回路基板を取り付けるための何らかの基台部材を用意する必要がある場合もある。 However, a conventional current sensor using a shunt resistor often employs a configuration in which a shunt resistor is provided on a predetermined circuit board. In such a configuration, the number of components increases as much as the shunt resistor is required as a dedicated component, leading to an increase in the size of the device configuration and the like, and it is necessary to prepare some base member for mounting the circuit board. In some cases.
そこで、本発明の第１の目的は、部品点数の削減及び小型化に適した電圧降下式電流計測装置を提供することである。 Accordingly, a first object of the present invention is to provide a voltage drop type current measuring device suitable for reducing the number of parts and reducing the size.
本発明の第２の目的は、温度変化に対する抵抗値の変化率を演算等によって考慮しなくても、シャント抵抗に流れる電流を温度変化に影響されずに容易に計測することができる電圧降下式電流計測装置を提供することである。 The second object of the present invention is to provide a voltage drop type that can easily measure the current flowing through the shunt resistor without being affected by the temperature change without considering the rate of change of the resistance value with respect to the temperature change by calculation or the like. It is to provide a current measuring device.
前記目的を達成するための技術的手段は、被計測電流が流れる経路に介装され、前記被計測電流を計測する電圧降下式電流計測装置であって、前記経路に介装される導電性の配線材と、前記配線材上に配設され、前記配線材の所定の２点間に生じる電圧降下量に基づいて前記被計測電流を計測する回路の少なくとも一部が設けられた回路基板と、前記配線材上における前記回路基板が配設せれた部分を少なくとも覆うように、前記配線材に装着されるケース体をさらに備える。 The technical means for achieving the object is a voltage drop type current measuring device that is interposed in a path through which a current to be measured flows and that measures the current to be measured, and that is a conductive current interposed in the path. A circuit board provided on the wiring material and at least a part of the circuit for measuring the measured current based on a voltage drop amount generated between two predetermined points of the wiring material; A case body attached to the wiring material is further provided so as to cover at least a portion where the circuit board is disposed on the wiring material.
また、好ましくは、前記ケース体の側縁部には、前記配線材の側縁部に前記配線材の幅方向の両側から抱え込むように係合してケース体を前記配線材に固定する係合爪が設けられるのがよい。 Preferably, the case body is fixed to the wiring member by engaging the side edge portion of the case body with the side edge portion of the wiring material so as to be held from both sides in the width direction of the wiring material. Claws should be provided.
さらに、好ましくは、前記配線材の両端部には、電気接続用及び固定用の固定具が挿通される貫通孔が設けられるのがよい。 Furthermore, it is preferable that both end portions of the wiring member are provided with through holes through which fixing tools for electrical connection and fixing are inserted.
また、好ましくは、前記固定具はボルトであり、前記ケース体には、前記配線材の前記貫通孔に対応する部分に、前記ボルトに螺着されるナットを収容して回り止めするナット収容部が設けられるのがよい。 Preferably, the fixing member is a bolt, and the case body includes a nut accommodating portion that retains a nut screwed to the bolt in a portion corresponding to the through hole of the wiring member and prevents the case from rotating. It is good to be provided.
さらに、好ましくは、前記ケース体には、前記配線材に配設された前記回路基板に対応する部分に、前記回路基板を収容する凹状の基板収容部が設けられ、前記基板収容部に注入された封止材により、前記回路基板が封止されるのがよい。 Further preferably, the case body is provided with a concave board housing portion for housing the circuit board at a portion corresponding to the circuit board disposed on the wiring member, and is injected into the board housing portion. The circuit board is preferably sealed with a sealing material.
また、好ましくは、前記配線材は、前記回路基板が配設されたその中間部分が他の部分に対して片側に部分的に張り出し、これによって前記ケース体が装着された際に前記中間部分の前記回路基板の実装面が前記基板収容部の開口部よりもさらに内方に嵌まり込むように屈曲されているのがよい。 Preferably, the wiring member has an intermediate portion on which the circuit board is disposed partially protrudes to one side with respect to the other portion, whereby the case body is attached to the intermediate portion. It is preferable that the mounting surface of the circuit board be bent so as to fit further inward than the opening of the board housing part.
さらに、好ましくは、前記被計測電流を計測する回路は、前記配線材と、前記配線材と同じ抵抗温度係数の材料で構成されて前記配線材に対して所定の接続点で電気的に接続されるセンス導体と、前記配線材において前記接続点から前記被計測電流の流れる方向に一定距離離れた第１の点と前記センス導体において前記接続点から所定の距離離れた第２の点との電位差を比較する電位差比較回路と、前記電位差比較回路からの信号に基づいて、前記第１の点と前記第２の点の電位が等しくなるまで前記センス導体に前記接続点から前記第２の点に向かって計測用電流を流す電流制御回路と、前記計測用電流に基づいて前記被計測電流を計測する電流計測回路と、を備えて構成され、前記回路基板には、前記配線材を除いた前記被計測電流を計測するための回路の構成要素のうちの前記センス導体が少なくとも設けられるのがよい。 Further preferably, the circuit for measuring the current to be measured is composed of the wiring material and a material having the same resistance temperature coefficient as the wiring material, and is electrically connected to the wiring material at a predetermined connection point. A potential difference between the sense conductor having a predetermined distance from the connection point in the wiring material and a second point having a predetermined distance from the connection point in the sense conductor. Based on the signal from the potential difference comparison circuit and the potential difference comparison circuit, the sense conductor is connected to the second point from the connection point until the potentials of the first point and the second point become equal. A current control circuit for flowing a measurement current toward the current measurement circuit, and a current measurement circuit for measuring the current to be measured based on the measurement current. The circuit board includes the wiring material excluding the wiring material. Measure current to be measured Better to the sense conductor provided at least of the components of a circuit for.
請求項１に記載の発明によれば、配線材がシャント抵抗として利用されるとともに、電流計測用の回路の少なくとも一部が設けられる回路基板の基台としても利用される構成であるため、専用のシャント抵抗や回路基板の基台を設ける構成に比して、部品点数の削減及び小型化により適した構成とすることができる。 According to the first aspect of the present invention, the wiring material is used as a shunt resistor and is also used as a base of a circuit board on which at least a part of a circuit for current measurement is provided. Compared with the configuration in which the shunt resistor and the circuit board base are provided, it is possible to make the configuration more suitable for reducing the number of parts and reducing the size.
また、回路基板の配線材に面した裏面側は配線材によって覆われて保護されるため、実質的に回路基板の表面側をケース体で覆うだけで、回路基板の保護を行うことができる。 Moreover, since the back surface side facing the wiring material of the circuit board is covered and protected by the wiring material, the circuit board can be protected by simply covering the front surface side of the circuit board with the case body.
請求項２に記載の発明によれば、ケース体に設けた係合爪によりケース体を配線材に固定するため、簡易な構成によりケース体の着脱を容易に行うことができる。 According to the invention described in claim 2, since the case body is fixed to the wiring member by the engaging claws provided on the case body, the case body can be easily attached and detached with a simple configuration.
請求項３に記載の発明によれば、配線材の両端部に設けられた貫通孔を利用して、電圧降下式電流計測装置の電気接続及び固定を同時に行うことができる。 According to the third aspect of the present invention, the voltage drop type current measuring device can be electrically connected and fixed at the same time using the through holes provided at both ends of the wiring member.
請求項４に記載の発明によれば、ケース体にナットを収容して回り止めするナット収容部が設けられているため、ボルト及びナットを用いた電気接続及び固定を容易に行うことができる。 According to the fourth aspect of the present invention, since the nut housing part that houses the nut and stops the rotation is provided in the case body, the electrical connection and fixing using the bolt and the nut can be easily performed.
請求項５に記載の発明によれば、ケース体の基板収容部に注入された封止材により回路基板が封止されるため、雨水や埃等から回路基板を保護することができる。 According to the fifth aspect of the present invention, since the circuit board is sealed by the sealing material injected into the board housing portion of the case body, the circuit board can be protected from rain water, dust, and the like.
請求項６に記載の発明によれば、配線材がその中間部分が部分的に片側に張り出すように屈曲され、これによってケース体が配線材に装着された際に中間部分の回路基板の実装面が基板収容部の開口部よりもさらに内方に嵌まり込むようになっているため、基板収容部内に注入された封止材中に回路基板を含む中間部分の実装面を確実に埋没させることができ、回路基板を確実に封止することができる。 According to the invention described in claim 6, when the wiring member is bent so that the intermediate portion thereof partially protrudes to one side, and the case body is attached to the wiring member, the circuit board is mounted on the intermediate portion. Since the surface fits further inward than the opening of the substrate housing portion, the mounting surface of the intermediate portion including the circuit board is securely buried in the sealing material injected into the substrate housing portion. And the circuit board can be reliably sealed.
請求項７に記載の発明によれば、配線材における電圧降下と、この配線材と同一の抵抗温度係数を有する材料のセンス導体の電圧降下とが、同一の温度変化による抵抗値変化を受けることを利用して、センス導体から流れ出る計測用電流を計測することで、配線材に流れる被計測電流を計測するので、温度変化に対する抵抗値の変化率を演算等によって考慮しなくても、配線材から流れ出るメイン電流を容易に計測することができる。 According to the seventh aspect of the present invention, the voltage drop in the wiring material and the voltage drop in the sense conductor made of the material having the same resistance temperature coefficient as the wiring material are subjected to the resistance value change due to the same temperature change. Is used to measure the current to be measured flowing from the sense conductor, thereby measuring the current to be measured flowing in the wiring material. The main current flowing out of the can be easily measured.
図１は本発明の一実施形態に係る電圧降下式電流計測装置（以下、単に「電流計測装置」という）の斜視図であり、図２はその断面図である。この電流計測装置１は、図１及び図２に示すように、金属製のバスバー（配線材）３と、回路基板５と、ケース体７とを備えて構成される。 FIG. 1 is a perspective view of a voltage drop type current measuring device (hereinafter simply referred to as “current measuring device”) according to an embodiment of the present invention, and FIG. 2 is a sectional view thereof. As shown in FIGS. 1 and 2, the current measuring device 1 includes a metal bus bar (wiring material) 3, a circuit board 5, and a case body 7.
＜回路構成等について＞
一般に、自動車など小電流〜大電流までを扱う環境においては、ジャンクション・ボックスと称される配線部品等での配電に、バスバーと呼ばれる銅や銅合金もしくはアルミなどで作られた板状の金属片が使用されることがあり、このバスバー３を、電流計測のためのシャント抵抗として利用することが可能である。そこで、本実施形態では、被計測電流の経路に介装するバスバー３をシャント抵抗として利用するとともに、回路基板５の基台等としても用いている。
<Circuit configuration>
In general, in an environment that handles a small current to a large current such as an automobile, a plate-shaped metal piece made of copper, copper alloy, or aluminum called a bus bar is used for power distribution in a wiring component called a junction box. The bus bar 3 can be used as a shunt resistor for current measurement. Therefore, in this embodiment, the bus bar 3 interposed in the path of the current to be measured is used as a shunt resistor and also used as a base for the circuit board 5.
また、例えばバスバー３の金属材料として銅を使用する場合、この銅の抵抗温度係数は、およそ０．００４／℃である。そして、自動車内の回路でシャント抵抗を使用する場合、雰囲気温度が−４０℃〜＋８５℃または＋１２５℃と温度変化の幅が１００℃以上と大きい。このように雰囲気温度の温度差が１００℃あれば、その抵抗値は１．４倍となる。よって、シャント抵抗としてバスバー３を用いて正確な電流値を知るためには、何らかの手段により抵抗値を補正する必要がある。 For example, when copper is used as the metal material of the bus bar 3, the resistance temperature coefficient of the copper is approximately 0.004 / ° C. And when using shunt resistance in the circuit in a motor vehicle, atmospheric temperature is -40 degreeC-+85 degreeC or +125 degreeC, and the width | variety of a temperature change is as large as 100 degreeC or more. Thus, if the temperature difference of the ambient temperature is 100 ° C., the resistance value becomes 1.4 times. Therefore, in order to know an accurate current value using the bus bar 3 as a shunt resistor, it is necessary to correct the resistance value by some means.
そこで、本実施形態では、回路基板５に、シャント抵抗して用いるバスバー３と同じ抵抗温度係数を有する材料（同じ材料を含む）で構成された温度補償用抵抗体としてのセンス導体１１（図３及び図４参照）を設け、このセンス導体１１をバスバー３に近接して配置し、バスバー３とセンス導体１１との温度変化が互いに同等となることを利用して、バスバー３の抵抗値の温度変化の補正を行うようにしている。 Therefore, in the present embodiment, the sense conductor 11 (FIG. 3) as a temperature compensating resistor composed of a material (including the same material) having the same resistance temperature coefficient as that of the bus bar 3 used as a shunt resistor on the circuit board 5. And the sense conductor 11 is arranged close to the bus bar 3, and the temperature of the resistance value of the bus bar 3 is utilized by utilizing the fact that the temperature changes of the bus bar 3 and the sense conductor 11 are equal to each other. The change is corrected.
具体的には、この電流計測装置１には、電流計測用の回路構成として、図３及び図４に示すように、メイン電流（被計測電流）Ｉ１が流れる経路に介装されるシャント抵抗としてのバスバー３と、このバスバー３内の所定の接続点Ｐｃｎに接続する温度補償用抵抗体としてのセンス導体１１と、バスバー３内において上記の接続点Ｐｃｎからメイン電流Ｉ１の流れる方向に一定距離だけ離れた点Ａ（第１の点）の電位とセンス導体１１内において上記接続点Ｐｃｎから所定の距離だけ離れた点Ｂ（第２の点）の電位とを比較する電位差比較回路１３と、点Ｂの電位と点Ａの電位が等しくなるまでセンス導体１１に上記の接続点Ｐｃｎから点Ｂに向かって計測用電流Ｉ２を流す電流制御回路１５と、この計測用電流Ｉ２に基づいてメイン電流Ｉ１を計測する電流計測回路１７とが備えられている。このバスバー３を除く電流計測用の回路構成のうち、少なくともセンス導体１１が回路基板５上に設けられるようになっている。本実施形態では、回路基板５には、センス導体１１、電位差比較回路１３、電流制御回路１５及び電流計測回路１７が設けられている。 Specifically, in the current measuring device 1, as a circuit configuration for current measurement, as shown in FIGS. 3 and 4, as a shunt resistor interposed in a path through which a main current (current to be measured) I1 flows. Bus bar 3, a sense conductor 11 as a temperature compensating resistor connected to a predetermined connection point Pcn in the bus bar 3, and a predetermined distance in the bus bar 3 from the connection point Pcn in the direction in which the main current I1 flows. A potential difference comparison circuit 13 for comparing the potential at a remote point A (first point) with the potential at a point B (second point) separated from the connection point Pcn within the sense conductor 11 by a predetermined distance; A current control circuit 15 that causes the measurement current I2 to flow from the connection point Pcn to the point B through the sense conductor 11 until the potential of B and the potential of the point A are equal, and the main current I based on the measurement current I2 A current measuring circuit 17 for measuring a is provided. Of the circuit configuration for current measurement excluding the bus bar 3, at least the sense conductor 11 is provided on the circuit board 5. In the present embodiment, the circuit board 5 is provided with a sense conductor 11, a potential difference comparison circuit 13, a current control circuit 15, and a current measurement circuit 17.
次に、各回路要素の電気的構成及び機能について簡単に説明する。バスバー３は、詳しくは後に説明するが、金属材料（ここでは、銅）で形成された板状体であり、シャント抵抗及び回路基板５の基台等として機能している。 Next, the electrical configuration and function of each circuit element will be briefly described. As will be described in detail later, the bus bar 3 is a plate-like body formed of a metal material (here, copper), and functions as a shunt resistor, a base of the circuit board 5, and the like.
センス導体１１は、例えばその端部が所定接続用の導体を介してバスバー３中の所定の接続点Ｐｃｎに接続されるもので、バスバー３と同じ抵抗温度係数を持つ金属材料（例えば、銅）が使用される。センス導体１１の抵抗値は、バスバー３の抵抗値と異なって設定していても差し支えなく、例えば１０，０００：１等の所定の比率に設定される。 The sense conductor 11 has an end portion connected to a predetermined connection point Pcn in the bus bar 3 through a predetermined connection conductor, for example, and a metal material (for example, copper) having the same resistance temperature coefficient as the bus bar 3 Is used. The resistance value of the sense conductor 11 may be set differently from the resistance value of the bus bar 3, and is set to a predetermined ratio such as 10,000: 1.
そして、バスバー３とセンス導体１１の温度に対する変化をほぼ同等とするために、回路基板５上のセンス導体１１がバスバー３に近接するように配置される。これにより、センス導体１１の電流を計測すれば、バスバー３の温度変化に対する抵抗値の変化率を考慮した計測を行うことができることから、計測時にバスバー３とセンス導体１１の温度係数をキャンセルすることができる。 The sense conductor 11 on the circuit board 5 is arranged so as to be close to the bus bar 3 in order to make the changes with respect to the temperature of the bus bar 3 and the sense conductor 11 substantially equal. Thus, if the current of the sense conductor 11 is measured, the measurement considering the rate of change of the resistance value with respect to the temperature change of the bus bar 3 can be performed. Therefore, the temperature coefficient of the bus bar 3 and the sense conductor 11 can be canceled at the time of measurement. Can do.
電位差比較回路１３は例えば演算増幅器（オペアンプ）であり、図４に示した非反転入力端子が、図３のようにバスバー３における上記接続点Ｐｃｎよりも負荷Ｍ側の中間点である接続点Ａに接続され、図４に示した反転入力端子が、図３のようにセンス導体１１の点Ｂに接続され、図４に示すように、両入力端子に与えられる電圧の差分が出力端子から出力される。 The potential difference comparison circuit 13 is, for example, an operational amplifier (op-amp), and the non-inverting input terminal shown in FIG. 4 is a connection point A that is an intermediate point on the load M side from the connection point Pcn in the bus bar 3 as shown in FIG. 4 is connected to the point B of the sense conductor 11 as shown in FIG. 3, and the difference between the voltages applied to both input terminals is output from the output terminal as shown in FIG. Is done.
そして、図３において、接続点Ｐｃｎと接続点Ａとの離間距離は、この間を流れる電流に対する抵抗値を規定することになるが、通電時に接続点Ｐｃｎと接続点Ａとの間で所定の電圧降下が生じて電位差比較回路１３での電圧検知精度に適応するような抵抗値を有するように、接続点Ｐｃｎと接続点Ａとの離間距離が設定される。このように、バスバー３の中間位置を接続点Ｐｃｎ及び接続点Ａとしているので、電位差比較回路１３での電圧検知精度に適応するような電圧降下を実現する場合に、その抵抗値を決定するための接続点Ｐｃｎと接続点Ａとの離間距離の設定を極めて容易に行うことができ便利である。 In FIG. 3, the separation distance between the connection point Pcn and the connection point A defines the resistance value with respect to the current flowing between them, and a predetermined voltage is applied between the connection point Pcn and the connection point A when energized. The separation distance between the connection point Pcn and the connection point A is set so as to have a resistance value suitable for the voltage detection accuracy in the potential difference comparison circuit 13 due to the drop. As described above, since the intermediate position of the bus bar 3 is set as the connection point Pcn and the connection point A, in order to determine the resistance value when realizing a voltage drop adapted to the voltage detection accuracy in the potential difference comparison circuit 13. This is convenient because the distance between the connection point Pcn and the connection point A can be set very easily.
電流制御回路１５は、例えばＰチャネルＦＥＴであって、ソースがセンス導体１１の点Ｂに接続され、ドレインが電流計測回路１７に接続される。そして、電流制御回路１５のゲートは電位差比較回路１３の出力端子に接続されている。すなわち、点Ｂからは、電位差比較回路１３の反転入力端子への経路と、電流制御回路１５への経路の２経路に分岐した回路が構成されていることになる。 The current control circuit 15 is a P-channel FET, for example, and has a source connected to the point B of the sense conductor 11 and a drain connected to the current measurement circuit 17. The gate of the current control circuit 15 is connected to the output terminal of the potential difference comparison circuit 13. That is, a circuit branched from the point B into two paths, that is, a path to the inverting input terminal of the potential difference comparison circuit 13 and a path to the current control circuit 15 is configured.
これにより、図３及び図４中のバスバー３にメイン電流Ｉ１が流れた際に生じるバスバー３での電圧降下によって電位差比較回路１３が電流制御回路１５のゲート入力を制御し、Ａ点とＢ点の電圧降下が等しくなるようにＢ点に電流Ｉ２が流れることになる。 Thereby, the potential difference comparison circuit 13 controls the gate input of the current control circuit 15 by the voltage drop in the bus bar 3 generated when the main current I1 flows through the bus bar 3 in FIG. 3 and FIG. The current I2 flows through the point B so that the voltage drops are equal.
電流計測回路１７は、例えば図４に示すように、計測用電流Ｉ２を電圧に変換するための抵抗器２１と、この抵抗器２１の一端の電位を計測するＡ／Ｄ変換器（検出回路）２３とを備える。抵抗器２１の他端は、Ａ／Ｄ変換器２３の基準電位（接地レベル）に接続される。抵抗器２１は、その抵抗温度係数がバスバー３の抵抗温度係数よりも十分に小さなものが用いられる。このため、本実施形態のように抵抗器２１を回路基板５上に配設しても、温度変化が生じた際の抵抗器２１の抵抗値の変化が、バスバー３の抵抗値の変化に比して十分に小さく抑えられる。 For example, as shown in FIG. 4, the current measurement circuit 17 includes a resistor 21 for converting the measurement current I2 into a voltage, and an A / D converter (detection circuit) that measures the potential of one end of the resistor 21. 23. The other end of the resistor 21 is connected to the reference potential (ground level) of the A / D converter 23. The resistor 21 having a resistance temperature coefficient sufficiently smaller than the resistance temperature coefficient of the bus bar 3 is used. For this reason, even if the resistor 21 is arranged on the circuit board 5 as in the present embodiment, the change in the resistance value of the resistor 21 when the temperature changes is compared to the change in the resistance value of the bus bar 3. And can be kept small enough.
次に上記回路構成の動作を説明する。 Next, the operation of the above circuit configuration will be described.
図３及び図４中の元電源（＋Ｂ）からの電源電圧が供給されると、バスバー３にメイン電流Ｉ１が流れ、このメイン電流Ｉ１が負荷Ｍに供給される。 When the power supply voltage from the original power supply (+ B) in FIGS. 3 and 4 is supplied, the main current I1 flows through the bus bar 3, and this main current I1 is supplied to the load M.
ここで、バスバー３にメイン電流Ｉ１が流れると、バスバー３での電圧降下によって、図４に示すように、電位差比較回路１３の非反転入力端子がローとなる。そうすると、電位差比較回路１３の出力端子がローとなり、これがＰチャネルＦＥＴである電流制御回路１５のゲートに与えられ、このゲート入力が制御されることで、電位差比較回路１３の動作に基づき図４中のＡ点とＢ点の電圧降下が等しくなるようにセンス導体１１に計測用電流Ｉ２が流れる。 Here, when the main current I1 flows in the bus bar 3, the non-inverting input terminal of the potential difference comparison circuit 13 becomes low as shown in FIG. Then, the output terminal of the potential difference comparison circuit 13 becomes low, and this is given to the gate of the current control circuit 15 which is a P-channel FET, and this gate input is controlled, so that the potential difference comparison circuit 13 in FIG. Current I2 for measurement flows through the sense conductor 11 so that the voltage drops at the points A and B are equal.
この場合、バスバー３の抵抗値をＲ１とし、センス導体１１の抵抗値をＲ２として、「Ｒ１×Ｉ１＝Ｒ２×Ｉ２」となるように、電位差比較回路１３が電流制御回路１５を制御する。かかる動作において、電位差比較回路１３の各入力端子には電流が流れ込まないので、分流電流としての計測用電流Ｉ２は全て電流制御回路１５のドレイン電流として電流計測回路１７に出力される。 In this case, the potential difference comparison circuit 13 controls the current control circuit 15 so that “R1 × I1 = R2 × I2”, where R1 is the resistance value of the bus bar 3 and R2 is the resistance value of the sense conductor 11. In such an operation, since no current flows into each input terminal of the potential difference comparison circuit 13, all the measurement current I 2 as a shunt current is output to the current measurement circuit 17 as the drain current of the current control circuit 15.
電流計測回路１７の抵抗器２１に計測用電流Ｉ２が流れると、この抵抗器２１の一端に生じる電圧がＡ／Ｄ変換器２３に与えられ、これにより計測用電流Ｉ２を計測することで、メイン電流Ｉ１を計測する。 When the measurement current I2 flows through the resistor 21 of the current measurement circuit 17, a voltage generated at one end of the resistor 21 is applied to the A / D converter 23, and the measurement current I2 is thereby measured. The current I1 is measured.
この場合、抵抗器２１の抵抗値をＲｏｕｔ、抵抗器２１の両端電圧をＶｏｕｔとすると、「Ｖｏｕｔ＝Ｒｏｕｔ×Ｉ２」であり、また「Ｉ２＝（Ｒ１／Ｒ２）×Ｉ１」であるため、「Ｖｏｕｔ＝Ｒｏｕｔ×（Ｒ１／Ｒ２）×Ｉ１」である。したがって、メイン電流Ｉ１は、Ａ／Ｄ変換器２３で計測されたＶｏｕｔに基づいて、「Ｉ１＝Ｖｏｕｔ×（Ｒ２／Ｒ１）／Ｒｏｕｔ」という式により演算で求めることができる。 In this case, assuming that the resistance value of the resistor 21 is Rout and the voltage across the resistor 21 is Vout, “Vout = Rout × I2” and “I2 = (R1 / R2) × I1”. Vout = Rout × (R1 / R2) × I1 ”. Therefore, the main current I1 can be obtained by calculation based on the expression “I1 = Vout × (R2 / R1) / Rout” based on Vout measured by the A / D converter 23.
＜構造等について＞
図５は本実施形態に係る電流計測装置の適用例を示す斜視図であり、図６はその電流計測装置等の分解斜視図である。この電流計測装置１は、図５及び図６に示すように、ボルト（固定具）３１とナット３３を用いて電気接続及び固定が行われるようになっている。
<About structure>
FIG. 5 is a perspective view showing an application example of the current measuring device according to the present embodiment, and FIG. 6 is an exploded perspective view of the current measuring device and the like. As shown in FIGS. 5 and 6, the current measuring device 1 is electrically connected and fixed using a bolt (fixing tool) 31 and a nut 33.
電流計測装置１のバスバー３は、図１、図２及び図６に示すように、所定の金属材料（ここでは、銅）によって形成された所定厚み（例えば、１〜２mm）を有する板状体であり、上述のようにシャント抵抗としての機能と、回路基板５の基台等としての機能とを担っている。このバスバー３は、被検出電流であるメイン電流Ｉ１の流れる方向に沿ってやや細長い略矩形板状の形態を有し、その長手方向の両端部に、ボルト３１が挿通される貫通孔３５が設けられている。 As shown in FIGS. 1, 2 and 6, the bus bar 3 of the current measuring device 1 is a plate-like body having a predetermined thickness (for example, 1 to 2 mm) formed of a predetermined metal material (here, copper). As described above, it has a function as a shunt resistor and a function as a base of the circuit board 5 and the like. The bus bar 3 has a substantially rectangular plate shape that is slightly elongated along the direction in which the main current I1 that is the detected current flows, and through holes 35 through which the bolts 31 are inserted are provided at both ends in the longitudinal direction. It has been.
また、バスバー３は、図２等に示すように、バスバー３の回路基板５が配設される長手方向の中間部分３ａがその他の部分（両端部分）に対して片側（回路基板５が配設される面側）に台形状に張り出すように、プレス成形等により屈曲されている。このバスバー３の屈曲形状の作用等については後述する。中間部分３ａには、後述する封止材３７（図２参照）の注入のための切欠部３９が設けられている。 In addition, as shown in FIG. 2 and the like, the bus bar 3 has a longitudinal intermediate portion 3a on which the circuit board 5 of the bus bar 3 is disposed on one side (the circuit board 5 is disposed) on the other portions (both end portions). And is bent by press molding or the like so as to protrude in a trapezoidal shape. The action of the bent shape of the bus bar 3 will be described later. The intermediate portion 3a is provided with a notch 39 for injecting a sealing material 37 (see FIG. 2) described later.
回路基板５は、ＰＣＢ（Printed Circuit Board）、ＦＰＣ(Flexible Printed Circuit）等の基板（本実施形態では、ＰＣＢ）が用いられ、上述のように、電流計測用の上記回路構成のうちの、バスバー３を除く少なくともセンス導体１１（本実施形態では、センス導体１１、電位差比較回路１３、電流制御回路１５及び電流計測回路１７）が設けられている。そして、回路基板５は、バスバー３の台形状に片側に張り出す中間部分３ａに配設される。回路基板５とバスバー３との固定は、回路基板５の接点のバスバー３への電気接続を兼ねた半田付け等により行われる。 As the circuit board 5, a board (PCB in this embodiment) such as a PCB (Printed Circuit Board) or an FPC (Flexible Printed Circuit) is used. As described above, the bus bar is one of the circuit configurations for current measurement. 3, at least the sense conductors 11 (in this embodiment, the sense conductor 11, the potential difference comparison circuit 13, the current control circuit 15, and the current measurement circuit 17) are provided. And the circuit board 5 is arrange | positioned in the intermediate part 3a which protrudes in the trapezoid shape of the bus bar 3 to one side. The circuit board 5 and the bus bar 3 are fixed by soldering that also serves as an electrical connection of the contacts of the circuit board 5 to the bus bar 3.
ケース体７は、絶縁材料（本実施形態では、樹脂）により形成され、バスバー３に装着されることにより、回路基板５の保護及びナット３３の収容保持の役目等を担っている。ケース体７は、図１及び図７ないし図９に示すように、バスバー３とほぼ同サイズの一方向にやや細長い矩形の平面形状を有している。 The case body 7 is formed of an insulating material (resin in the present embodiment), and is attached to the bus bar 3 so as to protect the circuit board 5 and to hold and hold the nut 33. As shown in FIGS. 1 and 7 to 9, the case body 7 has a slightly elongated rectangular planar shape in one direction substantially the same size as the bus bar 3.
ケース体７のバスバー３の中間部分３ａに対向する部分には、バスバー３に配設された回路基板５を収容する凹状の基板収容部４１が設けられている。バスバー３は、上述のように中間部分３ａが片側に張り出すように屈曲されているため、図２に示すように、ケース体７がバスバー３に装着された際に、中間部分３ａの回路基板５の実装面が基板収容部４１の開口部よりもさらに内方に嵌まり込むようになっている。このため、ケース体７の装着後に、バスバー３の切欠部３９の部分を介してゲル状の封止材３７を基板収容部４１内に注入する際、封止材３７を基板収容部４１の開口部又はその近傍まで充填すれば、回路基板５を含む中間部分３ａの実装面が封止材３７中に確実に埋没されるようになっている。 A concave substrate housing portion 41 for housing the circuit board 5 disposed on the bus bar 3 is provided at a portion of the case body 7 facing the intermediate portion 3 a of the bus bar 3. Since the bus bar 3 is bent so that the intermediate portion 3a projects to one side as described above, when the case body 7 is attached to the bus bar 3, as shown in FIG. 2, the circuit board of the intermediate portion 3a. The mounting surface 5 is fitted further inward than the opening of the substrate housing portion 41. For this reason, after the case body 7 is mounted, when the gel-like sealing material 37 is injected into the substrate housing portion 41 through the notch portion 39 of the bus bar 3, the sealing material 37 is opened in the substrate housing portion 41. If the portion or the vicinity thereof is filled, the mounting surface of the intermediate portion 3 a including the circuit board 5 is surely buried in the sealing material 37.
また、ケース体７のバスバー３の両端の貫通孔３５に対向する部分には、ナット３３を収容保持するナット収容部４３が設けられている。ナット収容部４３は、例えばバスバー３側に開口する凹状の構造を有し、その内周壁がナット３３の多角形状（ここでは、六角形）に対応した多角形の平面形状を有している。このため、ナット３３がナット収容部４３に嵌め込まれると、ナット収容部４３の内周壁がナット３３に外嵌し、ナット３３の回転を止めるようになっている。なお、ナット３３の回転を止めるための構造としては、これに限らず、ナット３３の複数の角部又は辺に係合してその回転を止める構造であれば、任意の構造を採用することができる。本実施形態では、外部からナット３３への操作及び状態確認等を行うため等の目的で、ナット収容部４３の底部に開口４５が設けられているとともに、ナット収容部４３の長手方向の端部の側壁が部分的に除去されて開口４６が設けられている。 Further, nut housing portions 43 for housing and holding nuts 33 are provided at portions of the case body 7 facing the through holes 35 at both ends of the bus bar 3. The nut accommodating portion 43 has, for example, a concave structure that opens to the bus bar 3 side, and the inner peripheral wall thereof has a polygonal planar shape corresponding to the polygonal shape (here, a hexagon) of the nut 33. For this reason, when the nut 33 is fitted into the nut housing portion 43, the inner peripheral wall of the nut housing portion 43 is fitted onto the nut 33 and the rotation of the nut 33 is stopped. The structure for stopping the rotation of the nut 33 is not limited to this, and any structure may be adopted as long as the structure is engaged with a plurality of corners or sides of the nut 33 to stop the rotation. it can. In the present embodiment, an opening 45 is provided at the bottom of the nut housing portion 43 for the purpose of performing an operation and state confirmation on the nut 33 from the outside, and the longitudinal end portion of the nut housing portion 43. An opening 46 is provided by partially removing the side wall.
このナット収容部４３にナット３３を嵌め込んだ状態でケース体７をバスバー３に装着すると、ナット３３が回り止めされた状態でバスバー３の貫通孔３５に対向配置される。このため、この電流計測装置１の電気接続等の際に、ナット３３が対向配置される側と反対側からボルト３１をバスバー３の貫通孔３５に挿入し、回転駆動するだけで、ナット３３がボルト３１に螺着されて締結されるため、作業者がわざわざナット３３の位置決め保持及び回り止め等を行う必要がない。 When the case body 7 is attached to the bus bar 3 with the nut 33 fitted in the nut accommodating portion 43, the nut 33 is disposed so as to face the through hole 35 of the bus bar 3 while the nut 33 is prevented from rotating. For this reason, when the current measuring device 1 is electrically connected, the bolt 33 is inserted into the through hole 35 of the bus bar 3 from the side opposite to the side on which the nut 33 is disposed and the nut 33 is simply rotated. Since the bolt 31 is screwed and fastened, it is not necessary for the operator to bother positioning and holding the nut 33 and prevent rotation.
また、ケース体７の長手方向と垂直な幅方向の両側の側縁部には、両側からバスバー３の側縁部に抱え込むようにして係合してケース体７をバスバー３に固定する第１ないし第３の係合爪４７，４９，５１が設けられている。第１の係合爪４７は、ケース体７の前記幅方向の一方側の側縁部におけるその長手方向の中間部分に、長手方向に所定区間連なって設けられている。第２及び第３の係合爪４９，５１は、ケース体７の前記幅方向の他方側の側縁部に、第１の係合爪４７と対向するように長手方向に互いに所定間隔をあけて設けられている。また、第２及び第３の係合爪４９，５１は、その両側にそれぞれ設けられたスリット４９ａ，５１ａにより形成されたその脚部４９ｂ，５１ｂが撓み変形することにより、第１の係合爪４７から離反する方向Ｃ（図１０参照）に撓み変形可能となっている。 In addition, the case body 7 is fixed to the bus bar 3 by engaging with the side edge portions on both sides in the width direction perpendicular to the longitudinal direction of the case body 7 so as to be held by the side edge portions of the bus bar 3 from both sides. Or third engagement claws 47, 49, 51 are provided. The first engaging claw 47 is provided at a middle portion in the longitudinal direction of the side edge portion on the one side in the width direction of the case body 7 so as to continue for a predetermined section in the longitudinal direction. The second and third engaging claws 49, 51 are spaced apart from each other in the longitudinal direction at the other side edge of the case body 7 in the width direction so as to face the first engaging claws 47. Is provided. Further, the second and third engaging claws 49, 51 are deformed by deformation of the leg portions 49b, 51b formed by the slits 49a, 51a provided on both sides thereof, respectively. It is possible to bend and deform in a direction C (see FIG. 10) away from 47.
このため、図１０の二点鎖線で示す状態のように、バスバー３の幅方向の一方側の側縁部を第１の係合爪４７に先に係合させた状態で、バスバー３の幅方向の他方側の側縁部を矢印Ｄで示すようにケース体７側に押し込むことにより、第２及び第３の係合爪４９，５１が第１の係合爪４７から離反する方向Ｃに撓み変形し、これによってバスバー３の他方側の側縁部の通過が許容される。そして、バスバー３の他方側の側縁部が第２及び第３の係合爪４９，５１を通過するのに伴って、係合爪４９，５１が復元力により元の状態に復帰し、図１０の実線で示す状態のように、バスバー３の幅方向の他方側の側縁部に係合し、ケース体７がバスバー３に固定される。 Therefore, as shown by the two-dot chain line in FIG. 10, the width of the bus bar 3 in a state where the side edge portion on one side in the width direction of the bus bar 3 is engaged with the first engagement claw 47 first. In the direction C in which the second and third engaging claws 49 and 51 are separated from the first engaging claw 47 by pushing the side edge of the other side toward the case body 7 as indicated by the arrow D. It bends and deforms, and thereby the passage of the other side edge of the bus bar 3 is allowed. As the other side edge of the bus bar 3 passes through the second and third engaging claws 49, 51, the engaging claws 49, 51 are restored to the original state by the restoring force. 10, the case body 7 is fixed to the bus bar 3 by engaging with the side edge portion on the other side in the width direction of the bus bar 3.
この装着状態では、バスバー３の台形状に張り出した中間部分３ａの長手方向の両側部分がケース体７の基板収容部４１の開口部から長手方向両側に連なる当接面５３に当接した状態で、第１ないし第３の係合爪４７，４９，５１がバスバー３の中間部分３ａの幅方向の両側の側縁部とケース体７側に引き付けるようにして係合することにより、ケース体７がバスバー３にがたつきなく固定されている。ケース体７の取外しは、第２及び第３の係合爪４９，５１を方向Ｃに撓ませて係合を解除することにより行うことができる。 In this mounted state, the both side portions in the longitudinal direction of the intermediate portion 3a projecting in a trapezoidal shape of the bus bar 3 are in contact with the contact surfaces 53 continuous from the opening of the substrate housing portion 41 of the case body 7 to both sides in the longitudinal direction. The first to third engaging claws 47, 49, 51 are engaged with the side edge portions on both sides in the width direction of the intermediate portion 3 a of the bus bar 3 so as to be attracted to the case body 7 side. Is fixed to the bus bar 3 without rattling. The case body 7 can be removed by bending the second and third engaging claws 49 and 51 in the direction C to release the engagement.
次に、電流計測装置１の組立について説明する。まず、回路基板５がバスバー３に半田付け等により電気接続及び固定される。続いて、ナット３３をナット収容部４３に嵌め込んだ状態で（他の手段により接続等を行う場合はボルト３３は省略可）、上述の図１０に示す要領でケース体７の係合爪４７，４９，５１をバスバー３に係合させて、ケース体７をバスバー３に装着する。続いて、バスバー３の切欠部３９の部分を介して、ケース体７の基板収容部４１内にゲル状の封止材３７を充填し、回路基板５を封止し、電流計測装置１の組立が完了する。 Next, assembly of the current measuring device 1 will be described. First, the circuit board 5 is electrically connected and fixed to the bus bar 3 by soldering or the like. Subsequently, in a state in which the nut 33 is fitted in the nut housing portion 43 (the bolt 33 can be omitted when connection or the like is performed by other means), the engaging claw 47 of the case body 7 in the manner shown in FIG. , 49, 51 are engaged with the bus bar 3, and the case body 7 is attached to the bus bar 3. Subsequently, the gel-like sealing material 37 is filled into the board accommodating portion 41 of the case body 7 through the notch 39 portion of the bus bar 3, the circuit board 5 is sealed, and the current measuring device 1 is assembled. Is completed.
次に、図５及び図６を参照して電流計測装置１の取付について説明する。図５及び図６に示す適用例では、車載用のバッテリ６１のプラス端子６３に接続される電流経路に電流計測装置１が介装され、その電流経路を流れる電流を計測するようになっている。具体的には、電流計測装置１の長手方向の一方側端部が中継用の導電金具６５を介してバッテリ６１のプラス端子６３に電気接続されている。 Next, attachment of the current measuring device 1 will be described with reference to FIGS. 5 and 6. In the application example shown in FIGS. 5 and 6, the current measuring device 1 is interposed in the current path connected to the plus terminal 63 of the in-vehicle battery 61, and the current flowing through the current path is measured. . Specifically, one end portion in the longitudinal direction of the current measuring device 1 is electrically connected to the plus terminal 63 of the battery 61 via the conductive metal fitting 65 for relay.
導電金具６５の一端部６５ａは、略リング状の構造を有し、プラス端子６３に外嵌されてボルト６６及びナット（図示せず）により締結固定及び電気接続される。 One end portion 65a of the conductive metal fitting 65 has a substantially ring-shaped structure, and is externally fitted to the plus terminal 63 and fastened and fixed and electrically connected by a bolt 66 and a nut (not shown).
導電金具６５の他端部６５ｂは、バッテリ１の側面に沿うように直角に折り曲げられてボルト３１の挿通用の貫通孔６５ｃが設けられており、電流計測装置１のバスバー３の上側にセットされた状態で、その貫通孔６５ｃを介してボルト３１がバスバー３の貫通孔３５内に挿入されてその内部のナット３３に螺着、締結され、これによって電流計測装置１の一方側端部と電気接続及び固定される。 The other end portion 65b of the conductive metal fitting 65 is bent at a right angle along the side surface of the battery 1 and provided with a through hole 65c for insertion of the bolt 31, and is set on the upper side of the bus bar 3 of the current measuring device 1. In this state, the bolt 31 is inserted into the through-hole 35 of the bus bar 3 through the through-hole 65c, and is screwed and fastened to the nut 33 inside thereof, whereby the one end of the current measuring device 1 is electrically connected. Connected and fixed.
電流計測装置１の他方側の端部には、電源供給用の電線６７，６９（図６では電線６９を省略）の末端部に圧着等により電気接続された端子７１が接続される。例えば、端子７１は、リング状の接続端７１ａを有しており、電流計測装置１のバスバー３の上側にセットされた状態で、その接続端７１ａの貫通孔を介してボルト３１がバスバー３の貫通孔３５内に挿入されてその内部のナット３３に螺着、締結され、これによって電流計測装置１の他方側端部と電気接続及び固定される。ここで、図５に示す電線６７はスタータへの電源供給用のものであり、電線６９はその他の負荷への電源供給用のものである。 The other end of the current measuring device 1 is connected to a terminal 71 which is electrically connected to the end of power supply wires 67 and 69 (the wire 69 is omitted in FIG. 6) by crimping or the like. For example, the terminal 71 has a ring-shaped connection end 71 a, and the bolt 31 is connected to the bus bar 3 through the through hole of the connection end 71 a while being set on the upper side of the bus bar 3 of the current measuring device 1. It is inserted into the through hole 35 and is screwed and fastened to the nut 33 inside thereof, thereby being electrically connected and fixed to the other end portion of the current measuring device 1. Here, the electric wire 67 shown in FIG. 5 is for supplying power to the starter, and the electric wire 69 is for supplying power to other loads.
このように電線計測装置１の取付が完了すると、図５に示すようにカバー７３が装着される。このカバー７３は、バッテリ６１のプラス端子６３から電流計測装置１までの電流経路に沿った構成部分を覆って絶縁及び保護する。 When the attachment of the electric wire measuring device 1 is completed in this way, the cover 73 is attached as shown in FIG. The cover 73 covers and insulates and protects the components along the current path from the positive terminal 63 of the battery 61 to the current measuring device 1.
なお、図５の図示例ではバッテリ６１のプラス端子６３に接続される電流経路に電流計測装置１を介装する構成としたが、電流計測装置１をバッテリ１のマイナス端子７５とボディとを結ぶ電流経路に介装するようにしてもよい。この場合、図５の構成とほぼ同様な構成を利用して、電流計測装置１の取付等を行うことができる。 In the illustrated example of FIG. 5, the current measuring device 1 is interposed in the current path connected to the plus terminal 63 of the battery 61. However, the current measuring device 1 is connected to the minus terminal 75 of the battery 1 and the body. It may be arranged in the current path. In this case, the current measuring device 1 can be attached using a configuration substantially similar to the configuration of FIG.
以上ように、本実施形態によれば、バスバー３がシャント抵抗として利用されるとともに、回路基板５及びケース体３の基台等としても利用される構成であるため、専用のシャント抵抗や回路基板５の基台を設ける構成に比して、部品点数の削減及び小型化により適した構成とすることができる。 As described above, according to the present embodiment, the bus bar 3 is used as a shunt resistor and is also used as a base for the circuit board 5 and the case body 3. Compared to the configuration in which five bases are provided, the configuration can be made more suitable for reducing the number of parts and reducing the size.
また、回路基板５のバスバー３に面した裏面側はバスバー３によって覆われて保護されるため、実質的に回路基板５の表面側をケース体７等で覆うだけで、回路基板５の保護を行うことができる。 Further, since the back side of the circuit board 5 facing the bus bar 3 is covered and protected by the bus bar 3, the circuit board 5 can be protected simply by covering the front side of the circuit board 5 with the case body 7 or the like. It can be carried out.
さらに、ケース体７に設けた係合爪４７，４９，５１によりケース体７をバスバー３に固定するため、簡易な構成によりケース体７の着脱を容易に行うことができる。 Further, since the case body 7 is fixed to the bus bar 3 by the engaging claws 47, 49, 51 provided on the case body 7, the case body 7 can be easily attached and detached with a simple configuration.
また、バスバー３の両端部に設けられた貫通孔３５を利用して、電流計測装置１の電気接続及び固定を同時に行うことができる。 Further, the current measuring device 1 can be electrically connected and fixed simultaneously using the through holes 35 provided at both ends of the bus bar 3.
さらに、ケース体７にナット３３を収容して回り止めするナット収容部４３が設けられているため、ボルト３１及びナット３３を用いた電気接続及び固定を容易に行うことができる。 Furthermore, since the nut housing portion 43 for housing the nut 33 and preventing it from rotating is provided in the case body 7, electrical connection and fixing using the bolt 31 and the nut 33 can be easily performed.
また、ケース体７の基板収容部４１に注入されたゲル状の封止材３７により回路基板５が封止されるため、雨水や埃等から回路基板５を保護することができる。 Further, since the circuit board 5 is sealed by the gel-like sealing material 37 injected into the board housing portion 41 of the case body 7, the circuit board 5 can be protected from rainwater, dust, and the like.
さらに、板状基台５がその中間部分３ａが部分的に片側に台形状に張り出すように屈曲され、これによってケース体７がバスバー３に装着された際に中間部分３ａの回路基板５の実装面が基板収容部４１の開口部よりもさらに内方に嵌まり込むようになっているため、基板収容部４１内に注入された封止材３７中に回路基板５を含む中間部分３ａの実装面を確実に埋没させることができ、回路基板５を確実に封止することができる。 Further, the plate-like base 5 is bent so that the intermediate portion 3a partially protrudes in a trapezoidal shape on one side, and when the case body 7 is attached to the bus bar 3, the circuit board 5 of the intermediate portion 3a is thus bent. Since the mounting surface is fitted further inward than the opening of the substrate housing 41, the intermediate portion 3a including the circuit board 5 in the sealing material 37 injected into the substrate housing 41 is provided. The mounting surface can be reliably buried and the circuit board 5 can be reliably sealed.
また、バスバー３における電圧降下と、このバスバー３と同一の抵抗温度係数を有する材料のセンス導体１１の電圧降下とが、同一の温度変化による抵抗値変化を受けることを利用して、センス導体１１から流れ出る計測用電流を計測することで、バスバー３に流れるメイン電流を計測するので、温度変化に対する抵抗値の変化率を演算等によって考慮しなくても、バスバー３から流れ出るメイン電流を容易に計測することができる。 Further, by utilizing the fact that the voltage drop in the bus bar 3 and the voltage drop in the sense conductor 11 made of the material having the same resistance temperature coefficient as the bus bar 3 are subjected to the resistance value change due to the same temperature change, the sense conductor 11 is used. The main current flowing through the bus bar 3 is measured by measuring the measurement current flowing out of the bus bar 3 so that the main current flowing out of the bus bar 3 can be easily measured without taking into account the rate of change of the resistance value with respect to the temperature change. can do.
１ 電圧降下式電流計測装置
３ バスバー
５ 回路基板
７ ケース体
１１ センス導体
１３ 電位差比較回路
１５ 電流制御回路
１７ 電流計測回路
３５ 貫通孔
３７ 封止材
４１ 基板収容部
４３ ナット収容部
４７，４９，５１ 係合爪
DESCRIPTION OF SYMBOLS 1 Voltage drop type current measuring device 3 Bus bar 5 Circuit board 7 Case body 11 Sense conductor 13 Potential difference comparison circuit 15 Current control circuit 17 Current measurement circuit 35 Through-hole 37 Sealing material 41 Substrate accommodating part 43 Nut accommodating part 47, 49, 51 Engaging claw
Claims (7)
前記経路に介装される導電性の配線材と、
前記配線材上に配設され、前記配線材の所定の２点間に生じる電圧降下量に基づいて前記被計測電流を計測する回路の少なくとも一部が設けられた回路基板と、
前記配線材上における前記回路基板が配設せれた部分を少なくとも覆うように、前記配線材に装着されるケース体をさらに備える、電圧降下式電流計測装置。 A voltage drop type current measuring device that is interposed in a path through which a current to be measured flows and measures the current to be measured,
A conductive wiring member interposed in the path;
A circuit board provided on the wiring member and provided with at least a part of a circuit for measuring the measured current based on a voltage drop amount generated between two predetermined points of the wiring member;
A voltage drop type current measuring device further comprising a case body attached to the wiring material so as to cover at least a portion where the circuit board is disposed on the wiring material.
前記ケース体の側縁部には、前記配線材の側縁部に前記配線材の幅方向の両側から抱え込むように係合してケース体を前記配線材に固定する係合爪が設けられる、電圧降下式電流計測装置。 In the voltage drop type current measuring device according to claim 1,
The side edge of the case body is provided with an engaging claw for engaging the side edge of the wiring material from both sides in the width direction of the wiring material and fixing the case body to the wiring material. Voltage drop type current measuring device.
前記配線材の両端部には、電気接続用及び固定用の固定具が挿通される貫通孔が設けられる、電圧降下式電流計測装置。 In the voltage drop type current measuring device according to claim 1 or 2,
A voltage drop type current measuring device, wherein both ends of the wiring member are provided with through-holes through which electrical connection and fixing fixtures are inserted.
前記固定具はボルトであり、
前記ケース体には、前記配線材の前記貫通孔に対応する部分に、前記ボルトに螺着されるナットを収容して回り止めするナット収容部が設けられる、電圧降下式電流計測装置。 In the voltage drop type current measuring device according to claim 3,
The fixture is a bolt;
The voltage drop type current measuring device, wherein the case body is provided with a nut accommodating portion that accommodates a nut screwed to the bolt and stops the rotation at a portion corresponding to the through hole of the wiring member.
前記ケース体には、前記配線材に配設された前記回路基板に対応する部分に、前記回路基板を収容する凹状の基板収容部が設けられ、
前記基板収容部に注入された封止材により、前記回路基板が封止される、電圧降下式電流計測装置。 In the voltage drop type current measuring device according to any one of claims 1 to 4,
The case body is provided with a concave board housing portion for housing the circuit board at a portion corresponding to the circuit board disposed on the wiring member,
A voltage drop type current measuring device in which the circuit board is sealed by a sealing material injected into the substrate housing portion.
前記配線材は、前記回路基板が配設されたその中間部分が他の部分に対して片側に部分的に張り出し、これによって前記ケース体が装着された際に前記中間部分の前記回路基板の実装面が前記基板収容部の開口部よりもさらに内方に嵌まり込むように屈曲されている、電圧降下式電流計測装置。 In the voltage drop type current measuring device according to claim 5,
The wiring member is mounted on the circuit board at the intermediate portion when the intermediate portion on which the circuit board is disposed partially protrudes on one side with respect to the other portion, thereby mounting the case body. The voltage drop type current measuring device, wherein the surface is bent so as to fit further inward than the opening of the substrate housing portion.
前記被計測電流を計測する回路は、
前記配線材と、
前記配線材と同じ抵抗温度係数の材料で構成されて前記配線材に対して所定の接続点で電気的に接続されるセンス導体と、
前記配線材において前記接続点から前記被計測電流の流れる方向に一定距離離れた第１の点と前記センス導体において前記接続点から所定の距離離れた第２の点との電位差を比較する電位差比較回路と、
前記電位差比較回路からの信号に基づいて、前記第１の点と前記第２の点の電位が等しくなるまで前記センス導体に前記接続点から前記第２の点に向かって計測用電流を流す電流制御回路と、
前記計測用電流に基づいて前記被計測電流を計測する電流計測回路と、
を備えて構成され、
前記回路基板には、前記配線材を除いた前記被計測電流を計測するための回路の構成要素のうちの前記センス導体が少なくとも設けられる、電圧降下式電流計測装置。 In the voltage drop type current measuring device according to any one of claims 1 to 6,
The circuit for measuring the measured current is:
The wiring material;
A sense conductor composed of a material having the same resistance temperature coefficient as the wiring material and electrically connected to the wiring material at a predetermined connection point;
A potential difference comparison that compares a potential difference between a first point that is a fixed distance away from the connection point in the wiring material in the direction in which the current to be measured flows and a second point that is a predetermined distance away from the connection point in the sense conductor. Circuit,
Based on a signal from the potential difference comparison circuit, a current that causes a measurement current to flow from the connection point to the second point through the sense conductor until the potentials of the first point and the second point become equal A control circuit;
A current measurement circuit for measuring the measured current based on the measurement current;
Configured with
The voltage drop type current measuring device, wherein the circuit board is provided with at least the sense conductor among the components of the circuit for measuring the measured current excluding the wiring material.
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| JP2008039571A (en) * | 2006-08-04 | 2008-02-21 | Denso Corp | Current sensor |
| JP2011052998A (en) * | 2009-08-31 | 2011-03-17 | Denso Corp | Current detection device |
| JP2011164008A (en) * | 2010-02-12 | 2011-08-25 | Denso Corp | Current detector |
| WO2012137980A1 (en) * | 2011-04-05 | 2012-10-11 | Yazaki Corporation | Shunt resistance type current sensor |
| WO2013041603A1 (en) * | 2011-09-23 | 2013-03-28 | Continental Automotive Gmbh | Device for measuring a battery current |
| WO2017199620A1 (en) * | 2016-05-18 | 2017-11-23 | 株式会社豊田自動織機 | Terminal connection structure for battery pack |
| KR20170139103A (en) * | 2015-04-28 | 2017-12-18 | 코아가부시끼가이샤 | Current detection device |
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| JPWO2021241082A1 (en) * | 2020-05-29 | 2021-12-02 | ||
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2003
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| JP2008039571A (en) * | 2006-08-04 | 2008-02-21 | Denso Corp | Current sensor |
| JP2011052998A (en) * | 2009-08-31 | 2011-03-17 | Denso Corp | Current detection device |
| DE102010037237A1 (en) | 2009-08-31 | 2011-05-05 | Denso Corporation, Kariya-City | Apparatus for measuring electric current |
| JP2011164008A (en) * | 2010-02-12 | 2011-08-25 | Denso Corp | Current detector |
| US8513950B2 (en) | 2010-02-12 | 2013-08-20 | Denso Corporation | Current sensor |
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| WO2013041603A1 (en) * | 2011-09-23 | 2013-03-28 | Continental Automotive Gmbh | Device for measuring a battery current |
| CN103827674A (en) * | 2011-09-23 | 2014-05-28 | 大陆汽车有限责任公司 | Device for measuring a battery current |
| US9360500B2 (en) | 2011-09-23 | 2016-06-07 | Continental Automotive Gmbh | Device for measuring a battery current |
| KR20170139103A (en) * | 2015-04-28 | 2017-12-18 | 코아가부시끼가이샤 | Current detection device |
| KR102508028B1 (en) | 2015-04-28 | 2023-03-10 | 코아가부시끼가이샤 | current detection device |
| WO2017199620A1 (en) * | 2016-05-18 | 2017-11-23 | 株式会社豊田自動織機 | Terminal connection structure for battery pack |
| JPWO2017199620A1 (en) * | 2016-05-18 | 2019-03-14 | 株式会社豊田自動織機 | Battery pack terminal connection structure |
| WO2021090905A1 (en) * | 2019-11-07 | 2021-05-14 | Koa株式会社 | Shunt resistance module, and implementation structure of shunt resistance module |
| JP7490351B2 (en) | 2019-11-07 | 2024-05-27 | Koa株式会社 | Shunt resistor module and mounting structure of the shunt resistor module |
| JPWO2021241082A1 (en) * | 2020-05-29 | 2021-12-02 | ||
| WO2021241082A1 (en) * | 2020-05-29 | 2021-12-02 | アルプスアルパイン株式会社 | Electric current sensor |
| JP7472280B2 (en) | 2020-05-29 | 2024-04-22 | アルプスアルパイン株式会社 | Current Sensors |
| WO2022158158A1 (en) * | 2021-01-19 | 2022-07-28 | アルプスアルパイン株式会社 | Electric current detection device |
| JP7471469B2 (en) | 2021-01-19 | 2024-04-19 | アルプスアルパイン株式会社 | Current Detector |
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