WO2023112799A1

WO2023112799A1 - Sensor and measurement device

Info

Publication number: WO2023112799A1
Application number: PCT/JP2022/045135
Authority: WO
Inventors: 宏紀中沢; 貴史丸山; 健太池田; 悠樹柄澤; 沛宇夏
Original assignee: 日置電機株式会社
Priority date: 2021-12-16
Filing date: 2022-12-07
Publication date: 2023-06-22

Abstract

This sensor comprises a housing, a first thermally conductive material provided to an inner surface of the housing, and a second thermally conductive material connecting the first thermally conductive material and an electronic component provided in the interior of the housing. The first thermally conductive material has a higher thermal conductivity than the housing and has a wider area than the second thermally conductive material when viewed from the inside of the housing.

Description

Sensors and measuring devices

The present invention relates to sensors and measuring devices.

JP2011-060496A discloses an IC socket with a housing. At least a portion of the housing is made of a material with good thermal conductivity. This IC socket accommodates a semiconductor device and has contacts that come into contact with the leads of the semiconductor device.

The heat generated at the contact when a large current flows through the semiconductor device flows through the insulating plate to the housing and is released from the housing.

However, when this IC socket is used in a device, the heat generated by the current flowing through the semiconductor device is released from the housing of the IC socket into the housing of the device.

Parts related to measurement are housed inside the housing of this device. temperature drift of parts and the like can become large.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a sensor and a measuring device capable of suppressing temperature drift of an output signal caused by an increase in internal temperature.

A sensor according to one aspect of the present invention comprises a housing, a first thermally conductive material provided on an inner surface of the housing, an electronic component provided inside the housing, and the first thermally conductive material. a second thermally conductive material connecting the materials. The first thermally conductive material has a higher thermal conductivity than the housing and has a larger area than the second thermally conductive material when viewed from the inner surface side of the housing.

In this aspect, the heat generated by the electronic components inside the housing is transferred to the first thermally conductive material provided on the inner surface of the housing via the second thermally conductive material. Then, the heat transferred to the first thermally conductive material is released to the outside of the housing through the housing.

For this reason, compared to the case where the heat generated by the electronic component is radiated into the internal space of the housing, and the radiated heat is radiated from the housing to the outside through the air inside the housing, the electronic component Efficiency of dissipating generated heat is enhanced.

As a result, it is possible to reduce the influence of heat on the parts related to measurement provided inside the housing.

Therefore, it is possible to suppress the temperature drift of the output signal caused by the rise in the internal temperature of the housing.

In addition, by connecting the first thermally conductive material and the second thermally conductive material and using them, the first thermally conductive material provided on the inner surface of the housing can be used without being restricted by the mounting area of the electronic components. The area can be widened when viewed from the inner surface side. Further, the heat from the electronic component can be directly transmitted to a wide area of the housing by the first thermally conductive material having higher thermal conductivity than the housing, so that the electronic component can spread over a wide area of the housing. Heat is diffused, and the heat dissipation effect of the housing can be enhanced.

FIG. 1 is a block diagram showing the sensor according to the first embodiment. FIG. 2 is a cross-sectional view showing the sensor according to the first embodiment. FIG. 3 is a plan view showing the substrate of the sensor according to the first embodiment. FIG. 4 is a cross-sectional view showing the sensor according to the second embodiment. FIG. 5 is a cross-sectional view showing a sensor as a comparative example. FIG. 6 is a block diagram showing a measuring device according to the third embodiment.

Each embodiment of the present invention will be described below with reference to the accompanying drawings. Throughout this specification, the same or equivalent elements are given the same reference numerals.

<First Embodiment>
First, a sensor 10 according to the first embodiment will be described with reference to FIGS. 1 to 3. FIG. FIG. 1 is a block diagram showing a sensor 10 according to the first embodiment.

As shown in FIG. 1, the sensor 10 is a device that detects a physical quantity occurring in a measurement target as a detected quantity. As an example, the sensor 10 of the first embodiment constitutes a current sensor that detects the measurement current I flowing through the measurement conductor 12 that is the object to be measured.

In the first embodiment, the case where the sensor 10 constitutes a current sensor will be described, but the first embodiment is not limited to this. The sensor 10 according to the first embodiment may be a sensor that detects a physical quantity such as voltage or temperature that occurs in a measurement target as a detection quantity that is a quantity to be detected. Moreover, a measuring device for measuring a measurement value related to a measurement target, such as a voltmeter, a power meter, or a thermometer, which incorporates these sensors, may be configured.

(Block description)
The sensor 10 comprises a circular ring-shaped magnetic core 14 into which the measuring conductor 12 is inserted. A feedback winding 16 is wound around the magnetic core 14 , and a fluxgate element 18 is provided on a part of the magnetic core 14 .

In the first embodiment, the case where the fluxgate element 18 is provided in part of the magnetic core 14 will be described, but the first embodiment is not limited to this. For example, a portion of the magnetic core 14 may be provided with a Hall element or sensing winding.

An excitation circuit 20 and a detection circuit 22 are connected to the fluxgate element 18, and the excitation circuit 20 sends to the detection circuit 22 a signal with a frequency 2f that is twice the excitation frequency f. A signal output from the detection circuit 22 is transmitted to one end of the feedback winding 16 via the amplifier circuit 24 .

The amplifier circuit 24 is composed of electronic components that generate heat, such as operational amplifiers 26, power transistors, or ICs. This electronic component includes a shunt resistor 30, which will be described later.

The other end of the feedback winding 16 is connected to one end of a shunt resistor 30 forming a generator 28 that generates an output signal indicating the detection result, and the other end of the shunt resistor 30 is connected to a GND line 32. It is One end of the shunt resistor 30 is connected to an output terminal 34, and the voltage generated between one end and the other end of the shunt resistor 30 is output from the output terminal 34 as an output signal generated by the generator 28. do. The detection result includes the voltage generated between one end and the other end of the shunt resistor 30 as well as a signal after the voltage has been processed by a circuit such as amplification or filter.

In the first embodiment, the case where one end of the shunt resistor 30 is connected to the output terminal 34 will be described, but the first embodiment is not limited to this.

For example, one end of the shunt resistor 30 may be connected to the output terminal 38 via an additional circuit 36 such as an A/D converter or output amplifier. In this case, the additional circuit 36 of the A/D converter and/or the output amplifier shall be included in the generator 28 .

(Description of operation)
When the measurement current I flows through the measurement conductor 12 passing through the magnetic core 14 , the measurement current I flowing through the measurement conductor 12 generates a magnetic flux Φ inside the magnetic core 14 . Then, in order to cancel the magnetic flux Φ generated inside the magnetic core 14, a secondary current I2 flows through the feedback winding 16 on the secondary side. A magnetic flux Φ′ is generated inside the magnetic core 14 by the secondary current I2 flowing through the feedback winding 16 .

Here, the magnetic flux Φ cannot be canceled from the DC current to the low frequency range. Therefore, the residual magnetic flux (Φ-Φ') that cannot be canceled remains in the magnetic core 14 that constitutes the magnetic circuit.

This residual magnetic flux (Φ-Φ') is detected by the fluxgate element 18. The fluxgate element 18 forms an output for canceling the residual magnetic flux (Φ-Φ') together with the excitation circuit 20 and the detection circuit 22, and this output is passed through the amplifier circuit 24 as a secondary feedback current to the feedback winding. 16.

A secondary current I2 is output from the feedback winding 16 to which the secondary feedback current is input, and the secondary current I2 flows through the shunt resistor 30 that constitutes the generator 28 . This secondary current I2 is converted by the shunt resistor 30 into a voltage proportional to the measured current I, and the converted voltage is output from the output terminal 34 as an output signal.

In this way, the sensor 10 outputs from the output terminal 34 the detected amount indicating the magnitude of the measurement current I flowing through the measurement conductor 12 as the output signal generated by the generator 28 .

(Equipment configuration)
FIG. 2 is a cross-sectional view showing the sensor 10 according to the first embodiment.

As shown in FIG. 2, the sensor 10 has an insulating housing 40 that constitutes a housing. The insulating housing 40 is made of synthetic resin, which is an insulator having no conductivity. The insulating housing 40 has a cover 42 and a cover 44 . The

covers

42, 44 are formed in a container shape.

The

covers

42 and 44 are fixed by screwing at a plurality of locations with the openings facing each other. As a result, the insulating housing 40 having the housing space 46 inside is formed by the

covers

42 and 44 .

Cylindrical struts 48 are formed at a plurality of locations on the inner surface 44A of the cover 44 . A substrate 50 is supported on each post 48 . The substrate 50 is fixed to the cover 44 by screwing a screw (not shown) through the substrate 50 into the post 48 .

On the surface 50A of the substrate 50, electronic components including the operational amplifier 26 and the shunt resistor 30 forming the generator 28 shown in FIG.

Here, the electronic components include power transistors, ICs, etc., in addition to the operational amplifier 26 and the shunt resistor 30 .

The substrate 50 is housed inside the insulating housing 40 composed of the cover 42 and the cover 44 . Accordingly, a generator 28 that generates an output signal, which is a signal indicating the detection result, is provided inside the insulating housing 40 .

The substrate 50 has a surface 50A on which the operational amplifier 26 and the shunt resistor 30 are mounted on the cover 42 side. Further, the substrate 50 has a rear surface 50B on which a wiring pattern for forming an electronic circuit is formed, for example, is arranged on the cover 44 side. A gap is ensured between the inner surface 44A of the cover 44 and the rear surface 50B of the substrate 50 by a support column 48 that supports the substrate 50 .

A thermally conductive material 62 that is a first thermally conductive material is provided on the inner surface 42A of the cover 42 . A heat conductive material 64 is provided on the inner surface 44A of the cover 44 . Thus, in a state where the insulating housing 40 is formed by the cover 42 and the cover 44, the thermally conductive material 66 including the thermally conductive material 62 and the thermally conductive material 64 is provided on the inner surface of the insulating housing 40. .

Also, the thermally conductive material 62 and the thermally conductive material 64 have higher thermal conductivity than the insulating housing 40 .

The thermally conductive material 66 provided on the inner surface of the insulating housing 40 has electrical conductivity. This prevents electromagnetic waves from entering the accommodation space 46 from the outside.

Between the thermally conductive material 62 provided on the inner surface 42A of the cover 42 and the thermally conductive material 64 provided on the inner surface 44A of the cover 44 in the state where the insulating housing 40 is formed by the cover 42 and the cover 44. is configured to form a gap.

Specifically, in the first embodiment, the peripheral wall 70 of the cover 42 does not comprise the thermally conductive material 62 and the peripheral wall 72 of the cover 44 does not comprise the thermally conductive material 64 .

Accordingly, the thermally conductive material 62 and the thermally conductive material 64 are configured so as not to be connected to each other. That is, both thermally

conductive materials

62 , 64 are configured so as not to form a loop surrounding substrate 50 .

This configuration can prevent the formation of a one-turn coil. This suppresses the generation of an induced current due to the magnetic flux from the measurement conductor 12 in the conductive layer composed of the thermally conductive material 62 and the thermally conductive material 64 . Therefore, the measurement accuracy can be improved as compared with the case where the induced current flows in the conductive layer composed of the two thermally

conductive materials

62 and 64. FIG.

In addition, the thermally conductive material 66 provided on the inner surface of the insulating housing 40 is made of metal, and compared to the case where the thermally conductive material 66 is made of a material other than metal, the housing space is protected from the outside. The effect of suppressing electromagnetic waves from entering 46 is enhanced.

The thermally conductive material 66 provided on the inner surface of the insulating housing 40 is made of plating. In other words, the thermally conductive material 66 is provided on the inner surface of the insulating housing 40 by plating the

inner surfaces

42A and 44A of the

covers

42 and 44 .

In addition, by forming the thermally conductive material 66 by plating, a uniform thermally conductive material 66 is formed on the inner surface of the insulating housing 40 regardless of the presence or absence of unevenness. Furthermore, by plating the inner surface of the insulating housing 40 , the thermally conductive material 66 is formed over a wide area of the insulating housing 40 .

The thermally conductive material 66 formed by this plating process is formed thin, and the thermally conductive material 66 can be rephrased as a conductive thin film.

The plating that constitutes the thermally conductive material 66 is, for example, a layer formed of copper, aluminum, tin, or a combination of these alloys, or a layer of copper, aluminum, tin, or a combination of these alloys. Consists of things.

FIG. 3 is a plan view showing the substrate 50 of the sensor 10 according to the first embodiment.

As shown in FIG. 3, the substrate 50 housed in the insulating housing 40 is formed in a rectangular shape, and the substrate 50 has a circular hole 80 formed therein. The magnetic core 14 described above is arranged on the outer periphery of the circular hole 80 .

Although not shown, the cover 42 is formed with a circular ring-shaped bulging portion in which the magnetic core 14 is arranged. A first insertion hole into which the measurement conductor 12 to be measured can be inserted is formed inside the circular ring-shaped bulging portion. A second insertion hole is formed in a portion of the cover 44 corresponding to the first insertion hole.

As a result, by inserting the measuring conductor 12 (see FIG. 1) to be measured into each insertion hole formed in the insulating housing 40, the measuring conductor 12 is connected to the magnetic core provided inside the insulating housing 40. 14 to be inserted.

As shown in FIGS. 2 and 3, the board 50 constitutes a printed wiring board. A printed pattern 52 is formed on the surface 50A of the substrate 50, and lands and the like to which electronic components are soldered are formed on the printed pattern 52. As shown in FIG.

Thus, by soldering the leads of the electronic component to the lands, an electronic circuit is formed by the printed pattern 52 on the surface 50A of the substrate 50 and the wiring pattern electrically connected to the printed pattern 52.

The electronic parts to be soldered include the operational amplifier 26, the power transistor, the IC, etc. that constitute the amplifier circuit 24 described above. Another electronic component is the shunt resistor 30 described above.

The wiring pattern that connects the land to which the lead of the operational amplifier 26 is soldered and the land to which the lead of the shunt resistor 30 is soldered is formed thinner than the wiring pattern that connects other electronic components. As a result, the wiring pattern that electrically connects the operational amplifier 26 and the shunt resistor 30 has a larger thermal resistance than other wiring patterns, and heat is transmitted from the operational amplifier 26 to the shunt resistor 30 via the wiring pattern. the heat generated is suppressed.

The GND line 32 (see FIG. 1) formed by the wiring pattern of the substrate 50 is electrically connected to the thermally conductive material 66 .

As shown in FIG. 3, the operational amplifier 26 is arranged in the vicinity of the circular hole 80. Also, the shunt resistor 30 is arranged at a position obliquely away from the operational amplifier 26 . As a result, the distance from the operational amplifier 26 to the shunt resistor 30 is made larger than when the operational amplifier 26 and the shunt resistor 30 are arranged side by side.

As shown in FIG. 2, the operational amplifier 26 is a flat package type molded with synthetic resin, and the surface 26A of the operational amplifier 26 is flat. Also, the shunt resistor 30 is of the platform package type, and the surface 30A of the shunt resistor 30 is flat.

The operational amplifier 26 is connected to the thermally conductive material 62 provided on the inner surface 42A of the cover 42 that constitutes the insulating housing 40 via the thermally conductive material 90 that is the second thermally conductive material. As a result, the operational amplifier 26 provided inside the insulating housing 40 and the thermally conductive material 66 provided on the inner surface of the insulating housing 40 are connected by the thermally conductive material 90 .

It should be noted that the thermally conductive material 90 is composed of TIM (Thermal Interface Material) as an example.

Also, the shunt resistor 30 is connected via a thermally conductive material 92 to the thermally conductive material 62 provided on the inner surface 42A of the cover 42 that constitutes the insulating housing 40 .

The thermally

conductive materials

90, 92 are made of thermally conductive sheets, and the thermally

conductive materials

90, 92 are rubber-like sheet bodies. Also, the thermally

conductive materials

90 and 92 are made of silicone rubber having elasticity, thermal conductivity, electrical insulation, and flame retardancy.

An example of the thermally

conductive materials

90 and 92 is Sarcon. The sarcon has a thermal conductivity k of 1 W/m°C or more and 5 W/m°C or less.

The thermally conductive material 90 is formed in substantially the same shape as the surface 26A of the operational amplifier 26. This thermally conductive material 90 has a smaller area than the thermally conductive material 62 when viewed from the inner surface side of the insulating housing 40 .

One surface 90A of the thermally conductive material 90 is in surface contact with the surface 26A of the operational amplifier 26, and the other surface 90B is in surface contact with the thermally conductive material 62 provided on the cover 42.

Also, the thermally conductive material 92 is formed in substantially the same shape as the surface 30A of the shunt resistor 30. One surface 92A of the thermally conductive material 92 is in surface contact with the surface 30A of the shunt resistor 30, and the other surface 92B is in surface contact with the thermally conductive material 62 provided on the cover 42. .

The thermally

conductive materials

90, 92 are compressed while the cover 42 is screwed to the cover 44, and the compressibility is determined according to the specifications of the thermally

conductive materials

90, 92. As a result, the thermally

conductive materials

90 and 92 are pressed against the surface 26A of the operational amplifier 26 or the surface 30A of the shunt resistor 30 with a predetermined pressure on one

side

90A and 92A, and the

other sides

90B and 92B against the thermally conductive material 62. Pressed with a specified pressure.

In the first embodiment, the thermally conductive material 90 has substantially the same shape as the surface 26A of the operational amplifier 26, and the thermally conductive material 90 is arranged on the operational amplifier 26. However, in the first embodiment, It is not limited to this.

For example, the thermally conductive material 90 is formed larger than the surface 26A of the operational amplifier 26, and the portion of the thermally conductive material 90 extending to the outer periphery of the surface 26A of the operational amplifier 26 is brought into contact with the leads extending from the operational amplifier 26. good too. In this case, heat transferred to the leads of op amp 26 can escape through thermally conductive material 90 .

In addition, the case where the thermally conductive material 92 has substantially the same shape as the surface 30A of the shunt resistor 30 and the thermally conductive material 92 is arranged on the shunt resistor 30 will be described. It is not limited.

For example, the thermally conductive material 92 is formed larger than the surface 30A of the shunt resistor 30, and the portion of the thermally conductive material 92 extending to the outer periphery of the surface 30A of the shunt resistor 30 extends from the shunt resistor 30. may be brought into contact with the lead. In this case, heat transferred to the leads of shunt resistor 30 can escape through thermally conductive material 92 .

(Action and effect)
Next, the effects of the first embodiment will be described.

The sensor 10 in the first embodiment includes an insulating housing 40, a thermally conductive material 62 provided on the inner surface of the insulating housing 40, an operational amplifier 26 and a thermally conductive material 66 provided inside the insulating housing 40. and a thermally conductive material 90 connecting the . The thermally conductive material 62 has a higher thermal conductivity than the insulating housing 40 and has a wider area than the thermally conductive material 90 when viewed from the inner surface side of the insulating housing 40 .

According to this configuration, the heat generated by the operational amplifier 26 and the shunt resistor 30 inside the insulating housing 40 is transferred to the thermally conductive material 90 having a thermal conductivity k of 1 W/m° C. or more and 5 W/m° C. or less, for example. , 92 to the thermally conductive material 62 provided on the inner surface of the insulating housing 40 . The heat transferred to the thermally conductive material 62 is released to the outside of the insulating housing 40 through the insulating housing 40 .

Therefore, after the heat generated by the operational amplifier 26 is released to the housing space 46 inside the insulating housing 40, it is transferred to the insulating housing 40 via the air having a thermal conductivity k of 0.03 W/m°C. , the heat dissipation efficiency of the heat generated in the operational amplifier 26 is increased as compared with the case where the heat is emitted to the outside from the insulating housing.

As a result, it is possible to reduce the influence of heat on electronic components and the like related to measurement provided inside the insulating housing 40 .

Therefore, it is possible to suppress the temperature drift of the output signal caused by the rise in the internal temperature of the insulating housing 40 .

In addition, by using the thermally conductive material 62 and the thermally conductive material 90 connected to each other, the thermally conductive material 62 provided on the inner surface 42A of the insulating housing 40 is not restricted by the mounting area of the operational amplifier 26, and the insulating housing 40 The area can be widened when viewed from the inner surface 42A side. The heat from the operational amplifier 26 can be directly transmitted to a wide range of the insulating housing 40 by the thermally conductive material 62 having a higher thermal conductivity than the insulating housing 40, so that the heat can be transferred to a wide range of the insulating housing 40. It can diffuse heat and enhance the heat dissipation effect.

(Comparative example)
FIG. 5 is a cross-sectional view showing a sensor 200 as a comparative example. In FIG. 5, the same reference numerals are assigned to the same or equivalent portions as those of the first embodiment and the second embodiment described later.

As shown in FIG. 5 , in the sensor 200 according to the comparative example, the operational amplifier 26 and the shunt resistor 30 are covered with the sheet metal 104 . Op-amp 26 is connected to sheet metal 104 via comparative thermally conductive material 202 .

The heat generated by the operational amplifier 26 is transmitted to the sheet metal 104 through the comparative example thermally conductive material 202 and released from the sheet metal 104 to the housing space 46 inside the insulating housing 40 .

In this sensor 200 , the heat generated by the operational amplifier 26 is released into the housing space 46 inside the insulating housing 40 , then transmitted to the insulating housing 40 through the air in the housing space 46 . will be released to the outside.

Here, as described above, the thermal conductivity of air is lower than that of the thermally conductive material 90 (see FIG. 2). Therefore, the sensor 200 has poor heat radiation efficiency, and the heat generated by the operational amplifier 26 can affect the shunt resistor 30 .

However, in the sensor 10 of the first embodiment, the heat generated by the operational amplifier 26 can be efficiently released to the outside of the insulating housing 40 as described above.

It should be noted that in the first embodiment described above, the insulating housing 40 may be a conductive housing.

The sensor 10 of the first embodiment constitutes a current sensor that detects the measurement current I flowing through the measurement conductor 12 . In this sensor 10, the insulating housing 40 is made of synthetic resin, which is a non-conductive insulator, in order to ensure insulation.

Such an insulating housing 40 has poor heat dissipation, and when heat is released inside the insulating housing 40 , the heat tends to stay inside the insulating housing 40 . As a result, the influence of temperature drift increases, the operating temperature range becomes narrower than the specified value, and the maximum measured current becomes smaller than the specified value.

Specifically, when the heat emitted from the operational amplifier 26 and trapped inside the insulating housing 40 raises the temperature of the shunt resistor 30 or the electronic components of the additional circuit 36 additionally provided at the output, the output value changes. Offsets can occur and sensitivity drift can occur. This can degrade detection reproducibility and detection accuracy.

Also, due to the rise in the internal temperature of the insulating housing 40, the usable temperature or the maximum detectable current specified by the standard may be limited.

On the other hand, in the sensor 10 according to the first embodiment, it is possible to improve heat dissipation even if the insulating housing 40 having insulating properties is used. Therefore, it is possible to reduce the influence of the temperature drift described above, widen the operating temperature range, and increase the maximum measurement current while ensuring insulation from the outside.

In addition, it is possible to improve detection reproducibility and detection accuracy, and increase the usable temperature and maximum detectable current specified by the standard.

In addition, in the first embodiment, the generator 28 that generates a signal indicating the detection result is provided inside the insulating housing 40 .

According to this configuration, the heat from the operational amplifier 26 is generated in the generating section 28 compared to the case where the heat generated in the operational amplifier 26 can be released inside the insulating housing 40 and transferred to the generating section 28. It is possible to suppress the influence on the output signal indicating the result.

Here, in the first embodiment, the generation unit 28 includes the shunt resistor 30, and the resistance value of the shunt resistor 30 can vary with changes in temperature. When the resistance value of the shunt resistor 30 fluctuates, the output voltage fluctuates, which can affect the detection result.

Therefore, in the first embodiment, the heat generated by the operational amplifier 26 is released to the outside of the insulating housing 40 to suppress the temperature change of the shunt resistor 30 that constitutes the generating unit 28 and reduce the fluctuation of the detection result. can be suppressed.

Also, in the first embodiment, the insulating housing 40 is made of an insulator, and the thermally conductive material 62 has electrical conductivity.

According to this configuration, in the insulating housing 40 formed of a synthetic resin insulator for weight reduction, the intrusion of electromagnetic waves from the outside can be suppressed by the thermally conductive material 62 having electrical conductivity. . As a result, it is possible to suppress the influence of electromagnetic waves from the outside on the detection result.

Here, the sensor 10 of the first embodiment constitutes a current sensor that detects the measured current I by the magnetic flux Φ generated in the magnetic core 14. In such a configuration, by suppressing the invasion of electromagnetic waves from the outside, it is possible to suppress the influence of the electromagnetic waves on the magnetic core 14 and enhance the effect of suppressing the influence on the detection result.

Then, in the first embodiment, the thermally conductive material 62 having electrical conductivity is electrically connected to the GND line 32 formed by the wiring pattern of the substrate 50 . Therefore, it is possible to reduce common mode noise that indicates the influence of the common mode voltage.

Also, in the first embodiment, the thermally conductive material 62 is made of metal.

According to this configuration, compared to the case where the thermally conductive material 66 is made of a material other than metal, the effect of preventing electromagnetic waves from entering the insulating housing 40 from the outside can be enhanced.

Also, in the first embodiment, the thermally conductive material 62 is composed of plating formed on the inner surface of the insulating housing 40 .

According to this configuration, the thermally conductive material 62 can be formed in close contact with a wide range of the insulating housing 40 by plating the inner surface of the insulating housing 40 . As a result, the heat transferred to the thermally conductive material 66 can be diffused over a wide range, thereby promoting heat transfer to the insulating housing 40 .

Moreover, since the thermally conductive material 62 can be formed by plating, even if the insulating housing 40 has unevenness, the thermally conductive material 62 can be uniformly formed along the inner surface of the insulating housing 40. can. This makes it easier to form the thermally conductive material 62 than in the case where a metal sheet is provided on the inner surface of the insulating housing 40 .

The thermally conductive material 62 formed by this plating process is formed thin. Therefore, compared to the case where the thermally conductive material 62 is made of sheet metal, the weight of the insulating housing 40 can be reduced.

Also, in the first embodiment, the thermally conductive material 90 is composed of a thermally conductive sheet.

According to this configuration, it is possible to prevent problems that may occur when grease or the like adheres to the substrate 50, compared to the case where the thermally conductive material is made of grease or the like.

In addition, in the first embodiment, the shunt resistor 30 constituting the generator 28 is connected to the thermally conductive material 62 provided on the inner surface of the insulating housing 40 via the thermally conductive material 92. there is Therefore, the heat generated by the shunt resistor 30 can be released from the insulating housing 40 to the outside through the thermally conductive material 92 and the thermally conductive material 62 .

With this configuration, it is possible to enhance the effect of suppressing the temperature drift of the detected value.

<Second embodiment>
FIG. 4 is a diagram showing the sensor 100 according to the second embodiment. A sensor 100 according to the second embodiment is partially different from the sensor 10 according to the first embodiment. Parts that are the same as or equivalent to those in the first embodiment are denoted by the same reference numerals, descriptions thereof are omitted, and only different parts are described.

FIG. 4 is a cross-sectional view showing the sensor 100 according to the second embodiment.

As shown in FIG. 4, a sheet metal 104 is sandwiched between the thermally conductive material 102, which is the second thermally conductive material, provided between the operational amplifier 26 and the thermally conductive material 62 on the substrate 50 of the sensor 100. ing.

Specifically, the thermally conductive material 102 provided between the operational amplifier 26 and the thermally conductive material 62 is separated from the component-side thermally conductive material 106 located on the operational amplifier 26 side and the thermally conductive material 62 side. and a shared thermally conductive material 108 disposed in the . A sheet metal 104 is positioned between the component-side thermally conductive material 106 and the shared thermally conductive material 108 . As a result, the sheet metal 104 is sandwiched between the thermally conductive material 102 .

A shared thermally conductive material 108 is provided along the upper surface of the sheet metal 104 . A shared thermally conductive material 108 extends from the top of the operational amplifier 26 to the top of the shunt resistor 30 .

The component-side thermally conductive material 106 and the shared thermally conductive material 108 have different thickness dimensions and the same material as the thermally conductive material 90 in comparison with the thermally conductive material 90 of the first embodiment.

Each thermally

conductive material

106, 108 is arranged between the operational amplifier 26 and the thermally conductive material 62 in a compressed state, as in the first embodiment. As a result, the component-side thermally conductive material 106 adheres to the surface 26A of the operational amplifier 26 in surface contact and adheres to the sheet metal 104 in surface contact. Further, the shared thermal conductive material 108 adheres to the sheet metal 104 in surface contact and adheres to the thermal conductive material 62 in surface contact.

The sheet metal 104 is composed of a metal plate material. The sheet metal 104 has a length such that one end extends outside the operational amplifier 26 and the other end extends outside the shunt resistor 30 .

At one end of the metal plate 104, a one-end extension 104A extending toward the substrate 50 and a one-end extension 104B extending from the one-end extension 104A and extending along the substrate 50 are formed. It is The one-end extending portion 104B is in contact with the printed pattern 52 of the substrate 50, and is soldered to the GND line 32 (see FIG. 1) of the printed pattern 52, for example.

At the other end of the metal plate 104, the other end side extension part 104C extending toward the substrate 50 side and the other end side extension part extending from the other end side extension part 104C and extending along the substrate 50 are provided. 104D are formed. The other end side extension portion 104D is fixed in contact with the substrate 50 .

The sheet metal 104 covers the operational amplifier 26 and the shunt resistor 30. The sheet metal 104 constitutes a shield that blocks electromagnetic waves. This suppresses electromagnetic waves from entering the electronic circuit formed on the substrate 50 .

A resistance-side thermally-conductive material 110 is arranged above the shunt resistor 30, and the resistance-side thermally-conductive material 110 supports a portion of the sheet metal 104 described above. Between the sheet metal 104 supported by the resistive thermally conductive material 110 and the thermally conductive material 62 is the shared thermally conductive material 108 previously described.

The resistance-side thermally conductive material 110 has a different thickness dimension than the thermally conductive material 92 of the first embodiment, and is made of the same material as the thermally conductive material 92 .

The resistance-side thermally conductive material 110 is arranged between the shunt resistor 30 and the thermally conductive material 62 in a compressed state, as in the first embodiment. As a result, the resistance-side thermally conductive material 110 adheres to the surface 30A of the shunt resistor 30 in surface contact and adheres to the sheet metal 104 in surface contact.

(Action and effect)
Next, the effects of the second embodiment will be described.

In the sensor 100 of the second embodiment, the same or equivalent parts as those of the first embodiment can achieve the same effects as those of the first embodiment.

Further, in the sensor 100 of the second embodiment, the sheet metal 104 is sandwiched between the thermally conductive materials 102 .

According to this configuration, heat transfer from the operational amplifier 26 to the thermally conductive material 62 can be facilitated compared to the case where the sheet metal 104 is not sandwiched between the thermally conductive materials 102 . Thereby, the heat radiation effect to the outside of the insulating housing 40 can be enhanced.

In addition, by sandwiching the sheet metal 104 between the thermally conductive materials 102 , the thickness dimension from one surface to the other surface of the thermally conductive material 102 can be increased by the thickness of the sheet metal 104 .

Therefore, even if the gap from the operational amplifier 26 to the thermally conductive material 62 is large, the adhesion between the thermally conductive material 102 and the operational amplifier 26 and the adhesion between the thermally conductive material 102 and the thermally conductive material 62 It is possible to obtain a heat dissipation effect while ensuring the property.

Then, in the second embodiment, the sheet metal 104 arranged between the component-side thermally conductive material 106 and the shared thermally conductive material 108 is larger than the surface 26A of the operational amplifier 26.

Therefore, the heat transferred from the operational amplifier 26 to the sheet metal 104 through the component-side thermally conductive material 106 diffuses over the entire sheet metal 104 larger than the surface 26A of the operational amplifier 26, and then through the shared thermally conductive material 108. , can be transmitted over a wide area of the thermally conductive material 62 . As a result, heat can be dissipated from a wide range of the insulating housing 40 in which the thermally conductive material 62 is provided on the inner surface of the insulating housing 40 .

Therefore, compared to the case where the sheet metal 104 is formed to have the same size as the surface 26A of the operational amplifier 26, the heat dissipation effect can be enhanced.

It should be noted that in the second embodiment described above, the insulating housing 40 may be a conductive housing.

<Third Embodiment>
First, a measuring device 300 according to the first embodiment will be described with reference to FIG. FIG. 6 is a block diagram showing a measuring device 300 according to the third embodiment.

As shown in FIG. 6, the measuring device 300 includes a measuring device main body 301 and a sensor 302. The sensor 302 is configured with the sensor 10 of the first embodiment or the sensor 100 of the second embodiment. The sensor 10 has the configuration described in the first embodiment, and the sensor 100 has the configuration described in the second embodiment.

The measurement device main body 301 includes an operation unit 304 , a measurement unit 305 , a processing unit 306 , a display unit 307 and a storage unit 308 . The sensor 302 is connected to the measuring section 305 of the measuring device body 301 via a cable 303 .

The storage unit 308 stores operation programs, measurement result data, and the like. The processing unit 306 operates according to the operation program stored in the storage unit 308 to control the measurement unit 305 and the display unit 307 .

The measurement unit 305 operates according to the control from the processing unit 306, and based on the detected amount of magnetism acquired from the sensor 302 (an output signal capable of specifying the current value of the measurement current), the measurement conductor 12 (Fig. 1) is executed to measure the current value of the measurement current I flowing through.

The operation unit 304 includes operation switches for instructing the setting of measurement conditions and the start and end of measurement by the measuring device 300, and the operation unit 304 outputs an operation signal to the processing unit 306 according to the switch operation. A display unit 307 receives a signal from the processing unit 306 and displays measurement results and the like.

The processing unit 306 comprehensively controls the measuring device body 301 . Specifically, the processing unit 306 controls the measurement unit 305 to execute the measurement process described above. Further, the processing unit 306 causes the display unit 307 to display the measurement result obtained by the measurement unit 305 , generates measurement result data that can identify the measurement result, and stores the measurement result data in the storage unit 308 .

(Action and effect)
Next, functions and effects of the third embodiment will be described.

A measuring device 300 in the third embodiment includes a sensor 302 and a measuring section 305 that measures a measured value related to the measurement conductor 12, which is the object to be measured, based on the output signal of the sensor 302.

In this configuration, the sensor 302 of the measuring device 300 is configured like the sensor 10 of the first embodiment or the sensor 100 of the second embodiment. Therefore, this measuring device 300 has the same effect as the first embodiment or the second embodiment.

Then, the measuring device 300 performs measurement based on the detected amount acquired from the sensor 302 . Therefore, the measurement apparatus 300 can perform measurement while suppressing the temperature drift of the output signal caused by the rise in the internal temperature of the sensor 302 .

Although the third embodiment shows the measuring device 300 that displays the measured value on the display unit 307, the third embodiment is not limited to this structure. For example, the measuring device 300 may be a device that outputs measured values to the outside in a wired or wireless manner.

In addition, although the third embodiment shows the measuring device 300 in which the sensor 302 is provided outside the measuring device main body 301, the third embodiment is not limited to this configuration. For example, measurement device 300 may be a device that incorporates sensor 302 .

Also, in the third embodiment, the measurement device 300 that performs communication between the sensor 302 and the measurement unit 305 using the cable 303 is shown, but the third embodiment is not limited to this configuration. For example, the measuring device 300 may be a device that communicates between the sensor 302 and the measuring section 305 using wireless communication means instead of the cable 303 .

Although the embodiments of the present invention have been described above, the above embodiments merely show a part of application examples of the present invention, and the technical scope of the present invention is not limited to the specific configurations of the above embodiments. do not have.

This application claims priority based on Japanese Patent Application No. 2021-204401 filed with the Japan Patent Office on December 16, 2021, and Japanese Patent Application No. 2022- filed with the Japan Patent Office on November 28, 2022. 188927, the entire contents of these applications are incorporated herein by reference.

10, 100, 200, 302 sensor 26 operational amplifier 28 generator 30 shunt resistor 40 insulating housing 42 cover 42A

inner surface

62, 64, 66, 90, 92, 102 thermally conductive material 104 sheet metal 106 component side thermally conductive material 108 Shared thermally conductive material 110 Resistance-side thermally conductive material 300 Measuring device 305 Measuring part

Claims

a housing;
a first thermally conductive material provided on the inner surface of the housing;
a second thermally conductive material connecting the electronic component provided inside the housing and the first thermally conductive material;
The first thermally conductive material has a higher thermal conductivity than the housing and has a larger area than the second thermally conductive material when viewed from the inner surface of the housing.
sensor.
A sensor according to claim 1, wherein
A generating unit that generates a signal indicating a detection result is provided inside the housing,
sensor.
A sensor according to claim 1 or claim 2,
The housing is made of an insulator,
The first thermally conductive material has electrical conductivity,
sensor.
A sensor according to any one of claims 1 to 3,
the first thermally conductive material is formed of metal;
sensor.
A sensor according to any one of claims 1 to 4,
The first thermally conductive material is composed of a plating formed on the inner surface,
sensor.
A sensor according to any one of claims 1 to 5,
The second thermally conductive material is composed of a thermally conductive sheet,
sensor.
A sensor according to any one of claims 1 to 6,
A sheet metal is sandwiched between the second thermally conductive materials,
sensor.
a sensor according to any one of claims 1 to 7;
a measurement unit that measures a measurement value related to a measurement target based on the output signal of the sensor;
A measuring device with