Current Sensor and Current Control System

Abstract

A current sensor 10 according to the present invention, which is capable of discharging, to the outside of an accommodation space, air heated by the heat of a busbar in order to suppress an increase in the temperature of the surroundings of electronic components such as a magnetism detection part and is suitable for measuring a large current, comprises: busbars 11 through which a current to be measured flows; and a housing 12 which has magnetism detection parts 14 capable of detecting a magnetic field generated by the flow of the current to be measured through the busbars 11, and an accommodation space 13 for accommodating the magnetism detection parts 14, portions of the busbars 11 being formed integrally with the housing, wherein one end 11a of each busbar 11 is connected to an external first unit 20 comprising a cooling device 21, the other end 11b of each busbar 11 is connected to an external second unit 30 of which the temperature becomes higher than that of the first unit 20 when the current to be measured flows, and the current value of the current to be measured can be measured from the detection results of the magnetism detection parts 14. In the current sensor 10, the housing 12 has, on a side facing the first unit 20, first ventilation ports 15A that pass through the accommodation space 13 from inside to outside.

Description

Technical Field

[0001] The present invention relates to a current sensor that detects a magnetic field generated by a current to be measured flowing through a bus bar and measures a current value of the current to be measured from the detected magnetic field.

Background Art

[0002] In recent years, with the increasing demand for decarbonization, the shift from an engine to a motor, that is, the gasoline vehicle / electrification (EV shift), is progressing in order to suppress the CO2 emissions during vehicle driving. As a current measuring device for measuring the current supplied to a three-phase motor, a current sensor is used (for example, Patent Document 1). As the EV shift spreads to large commercial vehicles such as trucks and buses, the motor capacity in hybrid vehicles and electric vehicles has increased, and the current to be measured by the current sensor used for motor control has also increased. In addition, the motor has an increasing number of opportunities to be continuously driven under high load conditions, and the continuously energized current has increased. The bus bar, which is the current path of the current to be measured, generates heat in an amount proportional to the square of the magnitude of the current. For this reason, as the continuously energized current to be measured increases, the amount of heat generated from the bus bar increases, and there is a problem that electronic components such as a magnetic detection unit arranged in the vicinity of the bus bar become hot.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Disclosure of the Invention

Problems to be Solved by the Invention

[0004] Since the current sensor described in Patent Document 1 includes a substrate having electronic components in a storage space closed by a case member, it is difficult to release the heat generated from the bus bar to the outside of the storage space. Therefore, the amount of heat generated by the bus bar increases, and the temperature inside the storage space becomes higher than the heat-resistant temperature of the magnetic detection unit, which may cause problems such as a decrease in the measurement accuracy of the current sensor and a shortening of the product life. Therefore, an object of the present invention is to provide a current sensor suitable for measuring a large current that can discharge the air heated by the heat of the bus bar to the outside of the storage space in order to suppress the temperature around electronic components such as the magnetic detection unit from rising.

Means for Solving the Problems

[0005] As means for solving the above-described problems, the present invention has the following configuration. A current sensor including a bus bar through which a current to be measured flows, a magnetic detection unit capable of detecting a magnetic field generated by the current to be measured flowing through the bus bar, and a housing having a storage space for housing the magnetic detection unit and a part of the bus bar integrally formed therein, wherein the current sensor is capable of measuring a current value of the current to be measured from the magnetic field detected by the magnetic detection unit, wherein one end of the bus bar is connected to an external first unit provided with a cooling device, and the other end is connected to an external second unit having a higher temperature than the first unit, and the housing has a first vent hole penetrating from the inside to the outside of the storage space on a side facing the first unit.

[0006] By providing the first vent hole in the region of the housing facing the first unit, an air flow is formed due to the temperature difference generated between the bus bar and the first unit when the bus bar generates heat, and the air inside the housing heated by the heat of the bus bar is discharged to the outside of the storage space, thereby suppressing the temperature rise inside the housing.

[0007] In addition to the first vent hole, the housing may have a second vent hole penetrating from the inside to the outside of the storage space on a side facing the second unit. Since the temperature of the second unit is higher than that of the first unit, an air flow is generated between the first unit and the second unit. Therefore, in addition to the first vent opening facing the first unit, by providing a second vent opening facing the second unit, the air flowing between the first unit and the second unit can easily pass through the storage space inside the housing. Accordingly, by utilizing the air flow generated by the temperature difference between the first unit and the second unit, the air in the storage space heated by the heat of the bus bar can be discharged (exhaust heat) to the outside of the storage space.

[0008] In this case, the magnetic detection unit may be disposed between the first vent opening and the second vent opening. With this configuration, by utilizing the air flow between the first vent opening and the second vent opening, the air around the magnetic detection unit heated by the heat of the bus bar can be efficiently discharged outside the housing. Accordingly, an increase in the temperature of the magnetic detection unit can be suppressed, and deterioration of the measurement accuracy of the magnetic detection unit can be prevented.

[0009] The magnetic detection unit may be disposed at a position facing the bus bar. The magnetic detection unit may be arranged so as to face the bus bar, that is, at least a part of the magnetic detection unit may overlap the bus bar when viewed along the perpendicular direction to the plate surface of the bus bar facing the magnetic detection unit. Thereby, the magnetic field of the bus bar can be efficiently detected by the magnetic detection unit.

[0010] The current sensor may include a flat shield member capable of suppressing external disturbance noise applied to the magnetic detection unit. The shield member includes a first shield member disposed on the side opposite to the side where the bus bar is disposed, with the magnetic detection unit as a reference, and a second shield member disposed on the side opposite to the side where the magnetic detection unit is disposed, with the bus bar as a reference, and paired with the first shield member. Since the external disturbance noise applied to the magnetic detection unit can be suppressed by the shield member, the detection accuracy of the current sensor is improved.

[0011] The current sensor has a shield member capable of suppressing external disturbance noise applied to the magnetic detection unit. The cross-sectional shape of the shield member when cut along a plane orthogonal to the extending direction of the bus bar is a U shape. When viewed along the extending direction of the bus bar, the shield member may be arranged to surround both sides of the bus bar in a direction orthogonal to the direction in which the bus bar and the magnetic detection unit overlap, and the opposite side of the bus bar from the side where the magnetic detection unit is arranged in the direction in which the bus bar and the magnetic detection unit overlap. By using a U-shaped shield member that surrounds three sides of the bus bar excluding the side where the magnetic detection unit is arranged, it is possible to suppress the influence of noise from bus bars other than the bus bar facing the magnetic detection unit when there are multiple bus bars.

[0012] The current sensor includes an electronic component different from the magnetic detection unit, and the electronic component may be arranged in the storage space. With this configuration, it is possible to suppress the influence of heat generation of the bus bar on the electronic component in addition to the magnetic detection unit.

[0013] A current control system characterized by including the current sensor of the present invention, the first unit, and the second unit. The first unit may be an inverter equipped with the cooling device, and the second unit may be a motor. With the above configuration, the air in the storage space heated by the heat of the bus bar is discharged to the outside of the storage space by using the air flow generated between the first unit with a relatively low temperature and the second unit with a relatively high temperature, and it is possible to suppress the temperature around the magnetic detection unit from rising.

Effects of the Invention

[0014] According to the present invention, by utilizing the air flow generated by the temperature difference in the vicinity of the current sensor, the air in the storage space heated by the heat of the bus bar can be discharged outside the storage space. Therefore, it is possible to suppress the temperature of the magnetic detection unit from rising due to the heat generation of the bus bar, and provide a current sensor with good measurement accuracy.

Brief Description of the Drawings

[0015]

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Best Mode for Carrying Out the Invention

[0016] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The same members in each drawing are denoted by the same reference numerals, and the description thereof will be omitted. In order to show the positional relationship of each member, reference coordinates are appropriately shown in each drawing. The reference coordinates are such that the extending direction of the bus bar is the X-axis direction, the direction orthogonal to the X-axis direction on the plate surface of the bus bar is the Y-axis direction, and the perpendicular direction to the plate surface of the bus bar is the Z-axis direction.

[0017] FIG. 12 is a perspective view of a conventional current sensor 100, and FIG. 13 is a cross-sectional view of the current sensor 100 in FIG. 12 cut along line A-A in the YZ plane. As shown in these figures, in the conventional current sensor 100, a substrate 109 having three magnetic detection units 104 is disposed in a storage space 103 within a housing 102 formed by a case member 102a and a cover member 102b, with a part of a bus bar 101 integrally formed therewith.

[0018] The storage space 103 is surrounded by the housing 102 and generally has no gap large enough to cause air convection, so the heat generated in the bus bar 101 accumulates inside. Therefore, when the measured current continuously flowing through the bus bar 101 increases, the temperature inside the storage space 103 rises due to the heat generation of the bus bar 101, and there is a risk that the detection accuracy of the current sensor 100 will decrease exceeding the heat-resistant temperature of the magnetic detection unit 104.

[0019] When measuring the current flowing between an inverter and a motor with the current sensor 100, one end of the bus bar 101 is connected to the inverter and the other end is connected to the motor. The inverter is provided with a cooling device for cooling an insulated gate bipolar transistor (IGBT). For this reason, when a measured current flows through the bus bar 101, for example, the temperature of the motor is about 170°C to 180°C and the temperature of the inverter is 100°C or less, and relatively the temperature of the inverter is lower than that of the motor. Therefore, due to the temperature difference between the motor and the inverter, an air flow (convection) is formed near the current sensor 100.

[0020] The present invention utilizes the air flow generated by the temperature difference around the current sensor to discharge the air inside the storage space 103 heated by the heat of the bus bar to the outside of the storage space 103, preventing the magnetic detection unit 104 from becoming high temperature and suppressing a decrease in the detection accuracy of the current sensor 100.

[0021] <Current Sensor> FIG. 1 is a perspective view of a current sensor 10 according to an embodiment of the present invention, and FIG. 2 is a perspective view showing a state in which the cover member 12b and the substrate 19 (see FIG. 3) are removed from the current sensor 10. FIG. 3 is a cross-sectional view of the current sensor 10 of FIG. 1 cut along line A-A in the YZ plane.

[0022] The current sensor 10 includes three bus bars 11 arranged side by side along the Y-axis direction, a case member 12a, and a cover member 12b, and has a storage space 13 inside a housing 12 composed of the case member 12a and the cover member 12b. A magnetic detection unit 14 capable of detecting a magnetic field generated when a current to be measured flows through the bus bar 11 is provided in the storage space 13.

[0023] The bus bar 11 is a plate-shaped conductive material extending in a strip shape along the width direction (X-axis direction) of the housing 12, and a part of it is integrally formed with the case member 12a by insert molding or the like. The bus bar 11 is for the current to be measured as a detection target to flow, and is composed of, for example, copper, brass, aluminum, or the like. The bus bar 11 is provided such that two opposing plate surfaces respectively correspond to the upper and lower sides (both sides in the Z-axis direction) of the housing 12.

[0024] Both end portions in the X-axis direction, which are connection portions of the bus bar 11 to the outside, do not necessarily have a shape that is line-symmetrical with respect to the Y-axis. Further, the bus bar 11 does not necessarily have a flat plate shape in portions other than the portion facing the magnetic detection unit 14, and may be subjected to, for example, bending processing.

[0025] The magnetic detection unit 14 detects a magnetic field (induced magnetic field) generated by a current to be measured flowing through the bus bar 11, and measures the current value of the current to be measured. As the magnetic detection unit 14, for example, a magnetoresistive effect element such as a GMR (giant magnetoresistive effect) element or a TMR (tunnel magnetoresistive effect) element that utilizes the magnetoresistive effect in which the electrical resistance changes due to an external magnetic field is used. The substrate 19 has a plate surface parallel to the XY plane, and the magnetic detection units 14 are respectively arranged at positions facing each bus bar 11 on the plate surface of the substrate 19 arranged in the accommodation space 13. At least a part of the sensor unit in the magnetic detection unit 14 faces the corresponding bus bar 11 and overlaps the bus bar 11 facing it when viewed along the Z axis. The three magnetic detection units 14 are preferably provided on the same side of the substrate 19.

[0026] As shown in FIG. 3, for each set of the three sets of bus bars 11 and magnetic detection units 14, the current sensor 10 is provided with a flat shield member 16 including a first shield member 16A and a second shield member 16B. The first shield member 16A and the second shield member 16B are configured by stacking a plurality of plate-like bodies made of metal having the same shape, for example. Note that the shield member 16 may be configured to include only one of the first shield member 16A and the second shield member 16B.

[0027] The first shield member 16A is formed integrally with the cover member 12b and is arranged on the side opposite to the side where the bus bar 11 is arranged with respect to the magnetic detection unit 14. The second shield member 16B is formed integrally with the case member 12a and is arranged on the side opposite to the side where the magnetic detection unit 14 is arranged with respect to the bus bar 11. Due to the first shield member 16A and the second shield member 16B, the influence of external disturbance noise applied to the magnetic detection unit 14 can be suppressed, and thus the detection accuracy of the current sensor 10 is improved.

[0028] FIG. 4 is a block diagram of a current control system 110 including the current sensor 10 of FIG. 1. As shown in the figure, the present invention can be implemented as a current control system 110 including a current sensor 10, a first unit 20, and a second unit 30 having a higher temperature than the first unit. For example, when measuring the current flowing between an inverter and a motor of an automobile using the current sensor 10, the first unit 20 is an inverter provided with a cooling device 21, and the second unit 30 is a motor. In this case, for example, the temperature of the motor becomes 170 to 180 °C, and the temperature of the inverter becomes 100 °C or lower. Therefore, due to the temperature difference, air movement occurs near the current sensor 10.

[0029] One end 11a of the bus bar 11 of the current sensor 10 is connected to an external first unit 20 provided with a cooling device 21, and the other end 11b is connected to the second unit 30. Since the second unit 30 has a higher temperature than the first unit 20, an air flow (convection) caused by the temperature difference is formed in the direction (X-axis direction) shown by the double-sided arrows in FIG. 4.

[0030] As shown in FIGS. 2 and 4, the housing 12 has a first vent 15A penetrating from the inside to the outside of the storage space 13 on the side facing the first unit 20. Also, on the side facing the second unit 30, it has a second vent 15B penetrating from the inside to the outside of the storage space 13. A part of the air flow along the X-axis direction caused by the temperature difference passes through the inside of the storage space 13 of the housing 12 through the first vent 15A and the second vent 15B. Therefore, even when the air in the storage space 13 becomes high temperature due to the heat generation of the bus bar 11, the high-temperature air can be discharged outside the storage space 13 by utilizing the air flow caused by the temperature difference, preventing the magnetic detection unit 14 from becoming high temperature and maintaining the detection accuracy of the current sensor 10.

[0031] From the perspective of taking in the air outside the storage space 13 near the magnetic detection unit 14 and preventing high-temperature air from remaining in the storage space 13, it is preferable to arrange the magnetic detection unit 14 between the first ventilation port 15A and the second ventilation port 15B. With this configuration, when a large current is continuously passed as the measured current, it is possible to suppress the heat generation of the bus bar 11 from affecting the magnetic detection unit 14 and maintain high measurement accuracy of the current sensor 10.

[0032] That the magnetic detection unit 14 is arranged between the first ventilation port 15A and the second ventilation port 15B means that at least a part of the magnetic detection unit 14 is located on the line segment connecting the first ventilation port 15A and the second ventilation port 15B. The line segment connecting the first ventilation port 15A and the second ventilation port 15B means a line segment whose points on both sides are respectively located in arbitrary regions at the first ventilation port 15A and the second ventilation port 15B.

[0033] As shown in FIGS. 1 to 3, both the first ventilation port 15A and the second ventilation port 15B are in a lattice shape in which three elongated rectangular holes having the longitudinal direction in the Z-axis direction are formed. In this way, by configuring the first ventilation port 15A and the second ventilation port 15B in a shape in which a plurality of slits are arranged, it is possible to cool the inside of the storage space 13 by utilizing the air flow due to the temperature difference and prevent foreign objects from entering the storage space 13.

[0034] Note that in the current sensor 10, three first ventilation ports 15A and three second ventilation ports 15B are respectively provided, which is the same as the number of the bus bar 11 and the magnetic detection unit 14. However, the number of the first ventilation ports 15A and the second ventilation ports 15B is not limited to three and may be different from the bus bar 11 and the magnetic detection unit 14.

[0035] <Modification Example 1> FIG. 5 is a block diagram of a current control system 120 including a current sensor 40 according to a modification example. The housing 12 of the current sensor 10 described above is provided with a first vent 15A and a second vent 15B, and utilizes the air flow caused by the temperature difference between the first unit 20 and the second unit 30 to discharge the heated air in the storage space 13 to the outside. In contrast, the current sensor 40 is different from the current sensor 10 in that it has only the first vent 15A facing the relatively cooler first unit 20 among the first unit 20 and the second unit 30 to which the bus bar 11 is connected.

[0036] When the housing 42 of the current sensor 40 has only the first vent 15A facing the first unit 20, when the air in the storage space 13 becomes hot due to the heat generation of the bus bar 11 in the housing 42, a temperature difference occurs between the bus bar 11 and the first unit 20. For this reason, an air flow due to the temperature difference occurs in the directions of the arrows on both sides in the X-axis direction shown in FIG. 5. Therefore, similar to the current sensor 10, by utilizing the air flow caused by the temperature difference between the first unit 20 and the bus bar 11, the air heated by the heat in the storage space 43 can be discharged to the outside, and it is possible to prevent the magnetic detection unit 14 from becoming hot and the measurement accuracy of the current sensor 40 from decreasing.

[0037] Even if a vent is provided only at a position not facing the first unit 20, the air in the storage space 13 is discharged to the outside, but by providing a vent (the first vent 15A) at a position facing the first unit 20, air replacement can be efficiently performed. If only the second vent 15B is provided, the air replacement efficiency is lower than that in Modification Example 1.

[0038] <Modification Example 2> FIG. 6 is a perspective view of a current sensor 50 according to a modification. For convenience of explanation, the figure shows a state in which the cover member 12b and the substrate 19 are removed, but the current sensor 50, like the current sensor 10, includes a cover member 12b, and the magnetic detection unit 14 is provided on the substrate 19.

[0039] The current sensor 50 includes a bus bar 51 that has a different shape from the bus bar 11, and is different from the current sensor 10 in a configuration where a second vent hole 55B is provided at a position corresponding to the shape of the bus bar 51. The configuration of the current sensor 40 other than these is the same as that of the current sensor 10.

[0040] As shown in FIG. 6, in the current sensor 50, the bus bar 51 is bent. In this case, when viewed along the X-axis direction, it overlaps with the first vent hole 15A, and when viewed along the Z-axis direction, a second vent hole 55B cannot be formed at a position overlapping with the bus bar 51. Therefore, in the current sensor 50, when viewed along the Z-axis direction, the first vent hole 15A is formed at a position overlapping each bus bar 51, and the second vent hole 55B is formed on both sides of each bus bar 51 in the Y-axis direction. As a result, in the storage space 53, an air flow is formed in an oblique direction with respect to the width direction (X-axis direction) of the case member 52a (housing 52). Even if the first vent hole 15A and the second vent hole 55B are configured in this way, similar to the current sensor 50, by utilizing the air flow due to the external temperature difference, the high-temperature air is discharged from the inside of the storage space 53 to the outside of the storage space 53, and the decrease in the measurement accuracy of the current sensor 50 due to the high temperature of the magnetic detection unit 14 can be suppressed. Note that, similar to the second vent hole 55B, the first vent hole 15A may be formed on both sides of each bus bar 51 in the Y-axis direction.

[0041] <Modification Example 3> FIG. 7 is a perspective view of a current sensor 60 according to another modification example, and FIG. 8 is a cross-sectional view of the current sensor 60 cut along the A-A line in the YZ plane of FIG. 7. The current sensor 60 is different from the current sensor 10 in the positions where the first vent hole 65A and the second vent hole 65B are provided in the housing 62. The configuration of the current sensor 60 other than these is the same as that of the current sensor 10.

[0042] The first unit 20 to which one end 11a of the bus bar 11 is connected and the second unit 30 to which the other end 11b is connected are arranged at various positions according to the design of the product. For this reason, the positions where the first unit 20 and the second unit 30 are arranged are not limited to the X-axis direction of the current sensor 10 shown in FIG. 4.

[0043] The current sensor 60 shown in FIGS. 7 and 8 utilizes the air flow formed by the temperature difference when the first unit 20 equipped with the cooling device 21 (see FIG. 4) is arranged on the side of the case member 62a in the Z-axis direction and the second unit 30 is arranged on the side of the cover member 62b in the Z-axis direction. Therefore, in order to utilize the external air flow, the first vent 65A is provided in the bottom surface (the surface where the perpendicular is parallel to the Z-axis) of the case member 62a, and the second vent 65B is provided in the upper surface (the surface where the perpendicular is parallel to the Z-axis) of the cover member 62b.

[0044] With this configuration, by utilizing the air flow in the Z-axis direction indicated by the double-sided arrows in FIG. 8, the air heated by the heat generated in the bus bar 11 can be discharged to the outside of the storage space 63, and the magnetic detection unit 14 can be prevented from becoming high temperature. In addition, in order to improve the exhaust heat efficiency from the storage space 13 due to the air movement in the Z-axis direction, holes penetrating the substrate 19 in the Z-axis direction may be provided in a part of the substrate 19. However, the substrate 19 is provided in the storage space 13 with a gap around it with the case member 62a. Therefore, even without providing holes, the heated air in the storage space 63 can be discharged to the outside by utilizing the air movement in the Z-axis direction.

[0045] The positions and numbers of the first vent 65A and the second vent 65B may be set as appropriate according to the first unit 20 and the second unit 30. Also, similar to the current sensor 40 shown in FIG. 5, the first vent 65A may be provided only on the surface facing the first unit.

[0046] <Modification Example 4> FIG. 9 is a perspective view of a current sensor 70 according to another modified example. First vent holes 75A and second vent holes 75B are respectively provided on both surfaces in the Y-axis direction orthogonal to the extending direction of the bus bar 11 in the case member 72a. For this reason, when the first unit 20 and the second unit 30 (see FIGS. 4 and 5) are provided on both sides in the longitudinal direction (Y-axis direction) of the housing 72 composed of the case member 72a and the cover member 72b, the heated air in the storage space 13 can be discharged to the outside by utilizing the movement of air caused by the temperature difference.

[0047] As described in Modified Examples 2 to 4, since the first unit and the second unit are provided at various positions according to the design, vent holes are provided at various positions corresponding to the arrangements of the first unit and the second unit. With this configuration, by utilizing the air flow caused by the temperature difference, the air heated by the heat in the storage space of the housing is discharged to the outside, preventing the temperature in the storage space from rising due to the heat generation of the bus bar when measuring a large current, and maintaining the measurement accuracy of the current sensor.

[0048] <Modified Example 5> FIG. 10 is a cross-sectional view of a current sensor 80 according to another modified example, showing the structure of a portion corresponding to the portion indicated by the line A-A of the current sensor 10 in FIG. 1. The current sensor 80 is different from the current sensor 10 in that it does not include the flat first shield member 16A, and instead includes a second shield member 86B having a U-shaped cross-sectional shape when cut along a direction orthogonal to the extending direction (X-axis direction) of the bus bar 11, and other configurations are the same as those of the current sensor 10.

[0049] The second shield member 86B is arranged so as to surround three sides of the bus bar 11 excluding the side on which the magnetic detection unit 14 in the bus bar 11 is arranged when viewed along the extending direction (X-axis direction) of the bus bar 11. That is, both sides of the bus bar 11 in the Y-axis direction and the opposite side of the side on which the magnetic detection unit 14 is arranged in the Z-axis direction are surrounded by the second shield member 86B. For this reason, the influence from the adjacent bus bar 11 other than the bus bar 11 facing the magnetic detection unit 14 can be suppressed by the second shield member 86B. Therefore, the influence of the external magnetic field on the magnetic detection unit 14 can be suppressed, and the detection accuracy of the current sensor 80 can be improved.

[0050] <Modification Example 6> FIG. 11 is a cross-sectional view of a current sensor 90 according to another modification example. The current sensor 90 is different from the current sensor 10 in that an electronic component 98 different from the magnetic detection unit 14 is arranged in the accommodation space 13 together with the magnetic detection unit 14, and other configurations are the same as those of the current sensor 10. Examples of the electronic component 98 include components constituting an IC chip such as a capacitor and a resistor.

[0051] Similar to the current sensor 10, since the housing 12 of the current sensor 90 is provided with the first vent 15A and the second vent 15B, the air heated by the heat generation of the bus bar 11 can be discharged outside the accommodation space 13 by using the air flow outside the accommodation space 13. Therefore, in the accommodation space 13, it is possible to prevent the magnetic detection unit 14 and the electronic component 98 from becoming high temperature due to the heat generation of the bus bar 11 and the detection accuracy of the current sensor 90 from decreasing.

[0052] The embodiments disclosed in this specification are illustrative in all respects and are not limited to this embodiment. The scope of the present invention is shown not by the description of only the above-described embodiments but by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

Industrial Applicability

[0053] The present invention is useful as a current sensor for measuring the current between, for example, a motor and an inverter, which can suppress the temperature rise of the magnetic detection unit by discharging the air heated by the large current flowing through the bus bar to the outside of the storage space, thereby suppressing the decrease in the measurement accuracy of the current sensor.

Explanation of Signs

[0054] 10: Current sensor 11: Bus bar 11a: One end 11b: The other end 12: Housing 12a: Case member 12b: Cover member 13: Storage space 14: Magnetic detection unit 15A: First ventilation port 15B: Second ventilation port 16: Shielding member 16A: First shielding member 16B: Second shielding member 19: Substrate 20: First unit 21: Cooling device 30: Second unit 40: Current sensor 42: Housing 43: Storage space 50: Current sensor 51: Bus bar 52: Housing 52a: Case member 53: Storage space 55B: Second ventilation port 60: Current sensor 62: Housing 62a: Case member 62b: Cover member 63: Storage space 65A: First ventilation port 65B: Second ventilation port 70: Current sensor 72: Housing 72a: Case member 72b: Cover member 75A: First vent 75B: Second vent 80: Current sensor 86B: Second shield member 90: Current sensor 98: Electronic component 100: Current sensor 101: Bus bar 102: Housing 102a: Case member 102b: Cover member 103: Storage space 104: Magnetic detection unit 109: Substrate 110: Current control system 120: Current control system

Claims

1. A current sensor comprising: a bus bar through which a current to be measured flows; a magnetic detection unit capable of detecting a magnetic field generated by the current to be measured flowing through the bus bar; and a housing having a storage space for housing the magnetic detection unit and having a part of the bus bar integrally formed therein, the current sensor being capable of measuring a current value of the current to be measured from the magnetic field detected by the magnetic detection unit, wherein one end of the bus bar is connected to an external first unit provided with a cooling device, and the other end is connected to an external second unit having a higher temperature than the first unit, and the housing has a first vent hole penetrating from the inside to the outside of the storage space on a side facing the first unit. The current sensor is characterized by this.

2. In addition to the first vent hole, the housing has a second vent hole penetrating from the inside to the outside of the storage space on a side facing the second unit. The current sensor according to Claim 1.

3. The magnetic detection unit is disposed between the first vent hole and the second vent hole. The current sensor according to Claim 2.

4. The magnetic detection unit is disposed at a position facing the bus bar. The current sensor according to Claim 1.

5. It has a flat shield member capable of suppressing external disturbance noise applied to the magnetic detection unit, and the shield member includes a first shield member disposed on a side opposite to the side where the bus bar is disposed with respect to the magnetic detection unit, and a second shield member disposed on a side opposite to the side where the magnetic detection unit is disposed with respect to the bus bar and paired with the first shield member. The current sensor according to Claim 1.

6. It has a shield member capable of suppressing external disturbance noise applied to the magnetic detection unit, and when the shield member is cut along a plane orthogonal to the extending direction of the bus bar, the cross-sectional shape is U-shaped, and when viewed along the extending direction of the bus bar, it is disposed so as to surround both sides of the bus bar in a direction orthogonal to the direction in which the bus bar and the magnetic detection unit overlap, and the side opposite to the side where the magnetic detection unit of the bus bar is disposed in the direction in which the bus bar and the magnetic detection unit overlap. The current sensor according to Claim 1.

7. It includes an electronic component different from the magnetic detection unit, and the electronic component is disposed in the storage space. The current sensor according to Claim 1.

8. A current control system comprising the current sensor according to claim 1, the first unit, and the second unit. Current control system. Claim 9 The first unit is an inverter provided with the cooling device, and the second unit is a motor. The current control system according to claim 8.

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