EP-4036939-B1 - SHUNT RESISTOR

Inventors

• MORIYAMA, YUU
• MURAKAMI, KENJI
• MUGISHIMA, Akio

Dates

Publication Date

20260513

Application Date

20191118

Claims (1)

1. A shunt resistor including a resistive body (10); a pair of base materials (11) integrally formed on the resistive body (10) across the resistive body (10); and measurement terminals (12) fixed on the base materials (11), characterized in that the base materials (11) are each provided with a plurality of cutout portions (13a, 13b) along a longitudinal direction of the base materials (11) and the plurality of cutout portions (13a, 13b) do not communicate with each other and are provided in a stepped manner, and wherein, of the plurality of cutout portions (13a, 13b), a cutout portion (13b) located farthest from the resistive body (10) is formed so that a depth (D2) is the deepest as compared with a depth (D1) of the other cutout portion (13a) wherein, when fixed on the base materials (11), the measurement terminals (12) are each fixed so as to be located above a bottom portion (13b1) of the depth (D2) of the cutout portion (13b) located farthest from the resistive body (10) and also further inside than one side portion (13a1) of a cutout portion (13a) located closest to the resistive body (10).

Description

Technical Field The present invention relates to a shunt resistor. Background Art A shunt resistor as described in Patent Literature 1 is known as a conventional shunt resistor. In this shunt resistor, a through hole is formed in each of two plate-like base materials integrally formed on a resistive body across the resistive body, and a current detection terminal having a first terminal portion inserted in the through hole and a second terminal portion protruding from the through hole is provided. Citation List Patent Literature Patent Literature 1: Japanese Patent Application Publicatio No. 2017-009419. Further relevant prior art regarding shunt resistors for improving TCR includes: US 2013/181807A1 and JP 2007 329421A. Summary of the Invention Technical Problem Incidentally, in the shunt resistor as described above, the temperature characteristics of combining the temperature characteristics of the resistive body and the temperature characteristics of the base materials are displayed. The temperature characteristics are one of the factors that affect the accuracy of the high-precision current sensor. Therefore, as a market demand, an improvement in temperature characteristics is required so that the absolute value of the temperature coefficient of resistance (TCR) is 50 ppm or less. Accordingly, in view of the foregoing problem, an object of the present invention is to provide a shunt resistor capable of improving the temperature characteristics. Solution to the Problem The foregoing object of the present invention is achieved by a shunt resistor according to claim 1. In is noted that reference signs in an embodiment to be described later are added in parentheses. According to the first aspect of the present invention, a shunt resistor (1) including a resistive body (10), a pair of base materials (11) integrally formed on the resistive body (10) across the resistive body (10), andmeasurement terminals (12) fixed on the base materials (11) is characterized in thatthe base materials (11) are each provided with a plurality of cutout portions (first cutout portion 13a, second cutout portion 13b) along a longitudinal direction of the base materials (11) andthe plurality of cutout portions (first cutout portion 13a, second cutout portion 13b) do not communicate with each other and are provided in a stepped manner. Further, the shunt resistor according to the above first aspect is characterized in that, of the plurality of cutout portions (first cutout portion 13a, second cutout portion 13b), a cutout portion (second cutout portion 13b) located farthest from the resistive body (10) is formed so that a depth (D2) is the deepest as compared with a depth (D1) of the other cutout portion (first cutout portion 13a). Further, the shunt resistor according to the above first aspect is characterized in that, when fixed on the base materials (11), the measurement terminals (12) are each fixed so as to be located above a bottom portion (13b1) of the depth (D2) of the cutout portion (second cutout portion 13b) located farthest from the resistive body (10) and also further inside than one side portion (13a1) of a cutout portion (first cutout portion 13a) located closest to the resistive body (10). Advantageous Effects of the Invention Next, advantageous effects of the present invention will be described with reference signs in the drawings. It is noted that reference signs in an embodiment to be described later are added in parentheses, but the present invention is not limited thereto. According to the first aspect of the present invention, the base materials (11) are each provided with the plurality of cutout portions (first cutout portion 13a, second cutout portion 13b) along the longitudinal direction of the base materials (11), and the plurality of cutout portions (first cutout portion 13a, second cutout portion 13b) do not communicate with each other and are provided in a stepped manner. This allows the absolute value of the temperature coefficient of resistance (TCR) to be 50 ppm or less, and as a result, the temperature characteristics can be improved. Further, of the plurality of cutout portions (first cutout portion 13a, second cutout portion 13b), the cutout portion (second cutout portion 13b) located farthest from the resistive body (10) is formed so that the depth (D2) is the deepest as compared with the depth (D1) of the other cutout portion (first cutout portion 13a). Therefore, the depth of the cutout portion can be adjusted so as not to affect the temperature characteristics of the resistive body 10, and as a result, the temperature characteristics can be improved. Further, the measurement terminals (12) are each fixed on the base material (11) so as to be located above the bottom portion (13b1) of the depth (D2) of the cutout portion (second cutout portion 13b) located farthest from the resistive body (10) and also further inside than one side portion (13a1) of the cutout portion (first cutout portion 13a) l