current sensor

Abstract

A current sensor (20) is capable of efficiently cooling a busbar by a cooling device (30). The current sensor (20) of the present invention comprises: a busbar (1); a shield (2) disposed opposite to the busbar (1); a magnetic sensor (3) disposed between the shield (2) and the busbar (1); and a frame (4) that integrally encloses a portion of the busbar (1), the shield (2) and the magnetic sensor (3). In the X-axis direction in which the busbar (1), the magnetic sensor (3) and the shield (2) are arranged, when the side in which the busbar (1) is disposed is designated as the X1 side, the busbar (1) is disposed closer to the X1 side than the center line (C) of the frame (4), and at least the X1 side of the frame (4) is disposed opposite to the cooling device (30).

Description

Technical Field

[0001] This invention relates to a current sensor that measures the current flowing through a busbar based on a magnetic field. Background Technology

[0002] In recent years, with increasing demands for decarbonization, a shift from engines to electric motors is underway to reduce CO2 emissions during vehicle operation—a process known as EV electrification. As EV electrification involves large commercial vehicles such as trucks and buses, the electric motor capacity in hybrid or electric vehicles is increasing, leading to larger current measurements from the current sensors used in motor control. The busbar, which serves as the current path for measuring this current, generates heat proportional to the square of the current magnitude. Therefore, as the continuous current increases with the motor capacity, the heat generated from the busbar also increases. This increased heat generation can lead to problems such as reduced accuracy or shortened product lifespan for current sensors. However, increasing the busbar cross-section to suppress heat generation is detrimental to the miniaturization and weight reduction of current sensors. Therefore, it is advisable to consider incorporating a cooling device to address the busbar heat generation, and to position the current sensor opposite the cooling device, creating a structure capable of cooling the busbar.

[0003] Patent Document 1 describes a busbar module with a current sensor for the purpose of suppressing the temperature rise of the current sensor and accurately measuring the current value of the busbar. The busbar module with a current sensor described in this document has at least one pair of shielding plates for shielding the magnetic field at the position where the busbar and the current sensor are sandwiched in the thickness direction.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2016-1168 Summary of the Invention

[0007] The technical problem that the invention aims to solve

[0008] In the busbar module with a current sensor described in Patent Document 1, the busbar is positioned near the center of the frame in the height direction, and other components such as a shielding plate are positioned between the busbar and the outer surface of the frame in the height direction. Therefore, it is difficult to install a cooling device opposite to the busbar to efficiently cool the busbar.

[0009] The purpose of this invention is to provide a current sensor that can efficiently cool the busbar using a cooling device.

[0010] Means for solving technical problems

[0011] As a means to solve the above-mentioned technical problems, the present invention has the following structure.

[0012] A current sensor, cooled by a cooling device, comprises: a busbar; a shield disposed opposite to the busbar; a magnetic sensor disposed between the shield and the busbar; and a frame integrally enclosing a portion of the busbar, the shield, and the magnetic sensor, characterized in that, in a first direction in which the busbar, the magnetic sensor, and the shield are arranged, with the side where the busbar is disposed as one side, the busbar is disposed on a side closer to the center of the frame, and at least one side of the frame is disposed opposite to the cooling device.

[0013] There is no shielding between the heat-generating busbar and the cooling device. The busbar is positioned close to the cooling device, so the busbar can be cooled efficiently by the cooling device.

[0014] Alternatively, the busbar may include: a first current path extending along a direction having a second directional component, the second direction being orthogonal to the first direction; and a second current path and a third current path extending from one end and the other end of the second direction of the first current path, respectively, along a direction having a third directional component, the third directional being orthogonal to the first direction and the second direction, wherein the magnetic sensor is configured opposite to the first current path and its sensitivity direction is the third directional.

[0015] By setting the sensitivity direction of the magnetic sensor to a third direction, when multiple phases of magnetic sensors are arranged side-by-side along the second direction, the influence of magnetic fields from adjacent phases can be suppressed, thus improving the sensitivity of the current sensor. Furthermore, since current sensors may contain a single or multiple magnetic sensors, the group of busbars, shields, and magnetic sensors corresponding to a single measured current is appropriately referred to as a "phase." This invention can be applied to single-phase current sensors with one set of phases and multi-phase current sensors with multiple sets of phases.

[0016] The measurement unit, consisting of the busbar, the shield, and the magnetic sensor, can also be arranged in parallel along the second direction.

[0017] Alternatively, the second current path extending from one end of the first current path and the third current path extending from the other end may be positioned differently in the first direction. When viewed from the first direction, the second current path of one of the adjacent busbars and the third current path of the other busbar may be configured to overlap at least partially.

[0018] According to this structure, when multiple measurement units are arranged in a row along the second direction, when viewed from the first direction, the second current path of one busbar and the third current path of another busbar in adjacent measurement units can overlap. Therefore, when multiple measurement units are arranged side by side along the second direction, the size of the current sensor in the second direction can be reduced.

[0019] Alternatively, the first current path may include: a first flat portion having one end; a second flat portion having the other end; and an intermediate portion connecting the first flat portion and the second flat portion, wherein, when viewed from the third direction, the intermediate portion extends in an inclined direction relative to the first direction.

[0020] According to this structure, the second current path of the other magnetic sensor can be configured such that it overlaps with the middle part of the magnetic sensor of one of the adjacent magnetic sensors when viewed from the first direction, thereby enabling a larger overlap area between the busbars of one phase and the busbars of the other phase.

[0021] The magnetic sensor can also be configured facing the side of the first flat portion in the first current path that is adjacent to the second flat portion. According to this structure, when viewed from the second direction, the magnetic sensor can be configured at a position overlapping the middle portion or the second flat portion, thus reducing the size of the current sensor in the first direction.

[0022] At this time, when viewing the first current path from the third direction, the length of the first flat portion in the second direction can also be greater than the sum of the length of the second flat portion and the length of the intermediate portion. By lengthening the first flat portion, the area through which the current, consisting of a component flowing approximately along the second direction, flows can be expanded within the first flat portion. Therefore, by arranging the magnetic sensor facing the side of the first flat portion closest to the second flat portion, high-precision current measurement is possible.

[0023] Alternatively, the busbar may have an exposed portion on one side of its surface in the first direction that is not covered by the frame, and this exposed portion is opposite to the cooling device. By providing an exposed portion in the area opposite the cooling device, the cooling efficiency of the busbar is improved.

[0024] The exposed portion can also be covered by a sealing component with higher thermal conductivity and insulation than the frame. By covering the exposed portion with a material that combines sealing and heat dissipation functions, cooling can be ensured, and short circuits and corrosion of the busbar can be suppressed.

[0025] Alternatively, the busbar may have a heat dissipation section on the portion opposite the magnetic sensor, and this heat dissipation section may be opposite the cooling device. The heat dissipation section may also be a wide section, wider than the measured portion, on both sides of the portion opposite the magnetic sensor when viewed along the first direction. The wide heat dissipation section may also have a hollow portion with a front-end opening.

[0026] By incorporating heat dissipation sections, the cooling efficiency of the cooling device for the busbars is improved. Furthermore, the increased surface area due to the wide and hollow heat dissipation sections further enhances heat dissipation efficiency.

[0027] A heat sink may also be disposed between the busbar and the cooling device on the side of the frame opposite to the cooling device. A fastening member is disposed on the side of the busbar opposite to the cooling device, and the fastening member can contact the busbar. The busbar may be integrally formed with the frame.

[0028] Based on these structures, cooling efficiency is improved because the heat from the busbars can be released through the radiator, nuts, and frame.

[0029] The substrate equipped with the magnetic sensor can also be connected to the frame via the boss portion of the frame.

[0030] Instead of making surface contact between the substrate and the frame on a wide surface, they are connected locally via a boss portion, thereby suppressing the transfer of heat from the frame to the magnetic sensor mounted on the substrate.

[0031] The cooling device may also have a shielding part on the part opposite to one side of the frame, which has the function of shielding magnetism.

[0032] When the current sensor and the cooling device are positioned opposite each other, the shielding part of the cooling device, which has the same function as the shielding component, can suppress the influence of interference noise from one side of the current sensor on the current sensor.

[0033] Invention Effects

[0034] In a current sensor cooled by a cooling device, no shielding is provided between the busbar and the cooling device, and the busbar is positioned closer to the cooling device than the center of the frame, thereby effectively cooling the heat generated from the busbar. Attached Figure Description

[0035] Figure 1A It is along Figure 1B A cross-sectional view of the current sensor cut by the XZ plane along the straight line Lx.

[0036] Figure 1B It is along Figure 1AA cross-sectional view of the current sensor cut by the straight line H through the XY plane.

[0037] Figure 2 This is a cross-sectional view of a modified current sensor.

[0038] Figure 3 This is a cross-sectional view of another variation of the current sensor.

[0039] Figure 4 This is a cross-sectional view of another variation of the current sensor.

[0040] Figure 5 These are cross-sectional views of current sensors in other variations.

[0041] Figure 6A It is along Figure 6B A cross-sectional view of the current sensor cut by the XZ plane along the straight line Lz.

[0042] Figure 6B It is a plan view showing the positional relationship of the various components of the current sensor.

[0043] Figure 7A This is a three-dimensional diagram showing the configuration of the current sensor to the cooling device.

[0044] Figure 7B This is a plan view showing the configuration of the current sensor to the cooling device.

[0045] Figure 7C yes Figure 7B A plan view of a modified example of the current sensor shown.

[0046] Figure 8A It is along Figure 8B A cross-sectional view of a current sensor, showing a modified example of a straight line Lz cut by the XZ plane.

[0047] Figure 8B This is a plan view of a modified current sensor.

[0048] Figure 9A It is along Figure 9B A cross-sectional view of a multiphase current sensor cut by the XZ plane along the straight line Lx.

[0049] Figure 9B It is along Figure 9A A cross-sectional view of a multiphase current sensor cut by the straight line H using the XY plane.

[0050] Figure 9C This is a plan view of a multiphase current sensor.

[0051] Figure 10A It is along Figure 10BA cross-sectional view of a modified multiphase current sensor, where the straight line Lx is cut by the XZ plane.

[0052] Figure 10B It is along Figure 10A A cross-sectional view of a modified multiphase current sensor, where the straight line H is cut by the XY plane.

[0053] Figure 10C This is a plan view of a modified multiphase current sensor.

[0054] Figure 11A It is along Figure 11B A cross-sectional view of a current sensor, showing a modified example of a straight line Lx cut by the XZ plane.

[0055] Figure 11B It is along Figure 11A A cross-sectional view of a current sensor, showing a modified example where the straight line H is cut by the XY plane.

[0056] Figure 11C This is a plan view of a modified current sensor. Detailed Implementation

[0057] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In each drawing, the same reference numerals are used to label the same parts, and descriptions are omitted where appropriate. In each drawing, XYZ coordinates are shown as reference coordinates.

[0058] Figure 1A It is a schematic representation along Figure 1B A cross-sectional view of the current sensor 20 cut by the XZ plane along the straight line Lx. Figure 1B It is a schematic representation along Figure 1A A cross-sectional view of the current sensor 20 cut by the straight line H using the XY plane.

[0059] The current sensor 20 includes a busbar 1, a shield 2, a magnetic sensor 3, and a frame 4 consisting of a housing 4a and a cover 4b, and is cooled by a cooling device 30 during use. Furthermore, the current sensor 20 can be implemented as a busbar module with a current sensor.

[0060] Busbar 1 is a conductor through which the measured current flows, and is the object detected by magnetic sensor 3. It is made of materials such as copper, brass, or aluminum. A portion of busbar 1 is embedded in the outer shell 4a of frame 4 and is integrally formed with the outer shell 4a. The heat generated by the current in busbar 1 is released (heat dissipation) through the outer shell 4a or directly from busbar 1. Furthermore, the number of measurement units 10 in current sensor 20, consisting of busbar 1, shielding member 2, and magnetic sensor 3, is not limited to... Figure 1BThe three shown. The distance between the busbars 1 of adjacent measuring units 10, and the shapes of the multiple busbars 1 can be the same or different.

[0061] The shielding element 2 is embedded in the cover 4b of the frame 4 by an embedded molding process. The shielding element 2 is arranged opposite to the busbar 1 and has the function of suppressing electromagnetic interference caused by the busbar 1. For example, it can be constructed by overlapping multiple metal plates of the same shape.

[0062] The magnetic sensor 3 is mounted on the substrate 5 and positioned between the shield 2 and the busbar 1 to detect the magnetic field generated by the measured current flowing through the busbar 1. For example, a magnetoresistive element such as a GMR element or a TMR element, which utilizes the magnetoresistive effect of resistance changing due to an external magnetic field, can be used as the magnetic sensor 3.

[0063] The frame 4 internally houses a portion of the busbar 1, a shield 2, and a magnetic sensor 3 as a single unit. Furthermore, the frame 4 is composed of an outer shell 4a that encloses a portion of the busbar 1 and a cover 4b that encloses the shield 2. The outer shell 4a is positioned on one side (X1 side), and the cover 4b is positioned on the other side (X2 side), with the X1 side of the frame 4 facing the cooling device 30. That is, since the outer shell 4a enclosing a portion of the busbar 1 is cooled by the cooling device 30, the busbar 1, which generates heat due to the flow of a large current, is also cooled. Additionally, the outer shell 4a and the cover 4b are fixed in close contact. Therefore, heat from the busbar 1 enclosed by the outer shell 4a is also dissipated through the cover 4b, cooling the busbar 1. Furthermore, by fixing the outer shell 4a and the cover 4b, the busbar 1, the shield 2, and the magnetic sensor 3 are fixed in predetermined positions.

[0064] The busbar 1 is positioned offset from the center of the width D4 of the frame 4 towards the X1 direction in the first direction (X-axis direction) in which the busbar 1, magnetic sensor 3, and shield 2 are arranged. That is, the busbar 1 is positioned closer to the cooling device 30 than the centerline C passing through the center of the frame 4 in the X-axis direction. By positioning the heat-generating busbar 1 closer to the cooling device 30, the current sensor 20 can be effectively cooled. Furthermore, unlike the busbar module with a current sensor described in Patent Document 1, the shield 2 is not provided between the busbar 1 and the cooling device 30. Therefore, the cooling efficiency of the busbar 1 of the cooling device 30 is not reduced by the shield 2 and the resin integrally molded with the shield 2. The cooling device 30 can be a device utilizing natural convection of external air or forced convection of air and / or water.

[0065] like Figure 1BAs shown, the frame 4 has a boss 41. Furthermore, the substrate 5, on which the magnetic sensor 3 is mounted, is connected to and fixed to the frame 4 via the boss 41. In this way, by providing the boss 41 on a part of the frame 4, the substrate 5 and the frame 4 do not make surface contact on a wider surface, thus suppressing the transfer of heat generated by the busbar 1 to the magnetic sensor 3.

[0066] Figure 2 This is a cross-sectional view of the modified current sensor 20, showing its relationship with... Figure 1A The corresponding part. Additionally... Figures 3 to 5 The other variations shown involve the same current sensor 20. For example... Figure 2 As shown, the busbar 1 may also have an exposed portion 14 on the side (X1 side) opposite to the magnetic sensor 3 in the X-axis direction, which is not covered by the outer shell 4a of the frame 4.

[0067] In this modified example, a heat dissipation (cooling) recess 42 is provided on the outer surface of the outer shell 4a on the X1 side of the frame 4, recessed to a position where the enclosed busbar 1 can be seen, thus exposing a portion of the X1 side surface of the busbar 1. The surface of the busbar 1 exposed within this heat dissipation recess 42 is the exposed portion 14. By cooling the exposed portion 14 via the heat dissipation recess 42 through a cooling device 30 located opposite the heat dissipation recess 42, the busbar 1 can be efficiently cooled by the cooling device 30 without passing through the outer shell 4a.

[0068] Figure 3 This is a cross-sectional view of the current sensor 20 in another variation. As shown in the figure, the exposed portion 14 of the busbar 1 can also be covered by the sealing member 6. The sealing member 6 is made of a material with a higher thermal conductivity than the outer shell 4a of the frame 4 and has insulating properties. Therefore, the following countermeasure is taken: by covering the exposed portion 14 of the surface of the busbar 1 with the sealing member 6, cooling is ensured while insulating the busbar 1 and inhibiting corrosion. In this invention, "having insulating properties" means a breakdown voltage of 5 to 10 kV / mm or higher. Thermal conductivity and insulation are generally a trade-off, but commercially available products that have adjusted the balance between thermal conductivity and insulation can be used. Examples of commercially available products that can be used as the sealing member 6 include insulating high thermal conductivity heat sinks such as FALTO-C, FEATHER-D6, Ramiel-LT, Ramiel-NEO, PT-SS, and HITS-Y (product names, all manufactured by Sekisui Chemicals Co., Ltd.).

[0069] Figure 4This is a cross-sectional view of the current sensor 20 in another variation. As shown in the figure, a heat sink 7 can also be provided between the busbar 1 and the cooling device 30. The heat sink 7 is provided on the X1 side surface of the outer casing 4a of the frame 4, and has heat dissipation fins with a concave-convex shape on its surface, and is positioned opposite the cooling device 30. Materials for the heat sink 7 that have high thermal conductivity include metals, alumina, ceramics, etc. In this variation, the heat sink 7 is provided in the heat dissipation recess 42 of the outer casing 4a in a manner that covers the exposed portion 14. Alternatively, it can be configured such that the heat dissipation recess 42 is not provided on the outer casing 4a, and the heat sink 7 is tightly attached to the X1 side surface of the outer casing 4a. Alternatively, it can be configured such that the X1 side surface of the outer casing 4a has the same concave-convex shape as the heat dissipation fins of the heat sink 7.

[0070] Figure 5 This is a cross-sectional view of the current sensor 20 in another variation. As shown in the figure, it can also be configured such that a nut (fastening member) 8 is disposed on the side of the busbar 1 opposite to the cooling device 30, and the nut 8 contacts the busbar 1. In addition, in this figure, the housing 4a and the nut 8 are shown as different components, but it is also possible for the nut 8 to be embedded in the housing 4a of the frame 4. In addition, the busbar 1 has a through hole (not shown) that communicates with the threaded hole of the nut 8. An external terminal (not shown) having the same through hole as the busbar 1 is disposed on the X2 side of the busbar 1 such that its through hole communicates with the threaded hole of the nut 8 and the through hole of the busbar 1. By inserting a bolt 9 from the through hole of the external terminal and fastening the bolt 9 and the nut 8, the external terminal (not shown) can be fixed to the busbar 1. In addition, since the nut 8 contacts the busbar 1, the same effect as increasing the heat dissipation area of ​​the busbar 1 by contacting the nut 8 can be obtained, thereby improving the cooling efficiency of the busbar 1.

[0071] Figure 6A It is along Figure 6B A cross-sectional view of the current sensor 40 cut by the XZ plane along the straight line Lz. Figure 6B This is a plan view showing the outlines of each part with dashed lines to represent the positional relationship of each component in the current sensor 40.

[0072] like Figure 6B As shown, the current sensor 40 differs from the current sensor 20, which has a curved portion of the busbar 1 when viewed from above, in that the busbar 1 has a straight, extending shape. Furthermore, the current sensor 40 has only one measurement unit 10, unlike the current sensor 20, which has multiple measurement units 10 (see reference 20). Figure 1B )different.

[0073] The busbar 1 of the current sensor 40 has: a first current path 11 extending along a direction having a component in the Y-axis direction (second direction) orthogonal to the X-axis direction (first direction); a second current path 12 and a third current path 13 extending from one end of the first current path 11 on the Y1 side and the other end on the Y2 side in the Y-axis direction, respectively, along directions having components in the Z-axis direction (third direction) orthogonal to the X-axis direction and the Y-axis direction. Furthermore, the magnetic sensor 3 is disposed opposite the first current path 11, and its sensitivity direction is in the Z-axis direction. Therefore, when multiple current sensors 40 are arranged side-by-side along the Y-axis direction, they are less susceptible to interference caused by the magnetic fields of adjacent current sensors 40, enabling good measurement accuracy.

[0074] "Extending along a direction having a component in the Z-axis direction" means that, for a line segment connecting the two ends of the extension direction of the flow path, the component in the Z-axis direction is the largest when decomposing the components using a reference axis. Preferably, more than 90% of the component is in the Z-axis direction, and more preferably, all of it is in the Z-axis direction, meaning the flow path extends along the Z-axis direction. Furthermore, "Extending along a direction having a component in the Y-axis direction" has the same meaning as "Extending along a direction having a component in the Z-axis direction" described above.

[0075] Figure 7A This is a perspective view schematically showing the configuration of the current sensor 40 toward the cooling device 30. Figure 7B This is a plan view showing the outlines of the various parts of the configured current sensor 40 using dashed lines. Figure 7C This is a plan view showing the outlines of various parts of a modified current sensor 40, indicated by dashed lines. The current sensor 40 includes a measurement unit 10 (see reference 10) consisting of a busbar 1, a shield 2, and a magnetic sensor 3. Figure 6A , Figure 6B (This can be considered as one phase.) At this time, by configuring multiple current sensors 40 in parallel, multiple phases can be configured in parallel.

[0076] By aligning the sensitivity axis S of the magnetic sensor 3 with the Z-axis, the influence of magnetic fields from adjacent current sensors 40 can be reduced when multiple current sensors 40 are arranged in the Y-axis direction. When current flows through the busbar 1 of a current sensor 40, the magnetic field generated in the first current path 11 extends concentrically around the first current path 11, thus failing to reach the magnetic sensor 3 of adjacent current sensors 40. Similarly, the magnetic fields generated in the second current path 12 and the third current path 13 extend concentrically around the second current path 12 and the third current path 13, respectively, and thus may reach the magnetic sensor 3 of adjacent current sensors 40. However, since the magnetic fields generated in the second current path 12 and the third current path 13 contain almost no Z-axis component, the magnetic sensor 3 of adjacent current sensors 40 is almost undetectable. In other words, by setting the sensitivity axis S to the Z-axis and arranging the current sensors 40 in the Y-axis direction, they are unaffected by the magnetic fields caused by the current in the busbar 1 of adjacent current sensors 40. Therefore, the measurement accuracy of the current sensor 40 becomes good. Additionally, the current sensor 40 can also be configured as a power supply card on the cooling device 30.

[0077] like Figure 7A As shown, the cooling device 30 circulates cooling water introduced and discharged from water-cooling ports 30a and 30b for cooling. For example, a cooling device 30 made of aluminum is used. To ensure insulation, the surface of the cooling device 30 in contact with the current sensor 40 can also be covered with ceramic. In the cooling device 30 shown in this figure, the current sensor 40 is in contact with the cooling device 30 on the X2 side in addition to the X1 side. Therefore, the current sensor 40 is cooled by the cooling device 30 from both sides in the X-axis direction. However, as... Figure 6A As shown, the busbar 1 is positioned closer to the X1 side than the center line C of the frame 4. There is no shielding component 2 on the X1 side of the busbar 1, so the effect of cooling the heat of the busbar 1 is greater on the X1 side than on the X2 side.

[0078] Additionally, in the cooling device 30, a shielding part 32 capable of shielding magnetism may be provided at a position opposite to one side (X1 side) of the frame 4 of the current sensor 40 (see reference). Figure 2 Since the shielding part 32 has the same function as the shielding member 2, the shielding part 32 of the cooling device 30 can prevent interference noise from entering from one side (X1 side) of the current sensors 20 and 40. In addition, when the shielding part 32 is provided, it is preferable that the insulation of the exposed part 14 of the current sensor 40, which will be described later, is ensured.

[0079] Figure 7B and 7CAn example of the shape of busbar 1 is shown. Busbar 1 can be configured, for example, as follows: Figure 7B The shape shown is based on the first current path 11, with the second current path 12 and the third current path 13 extending to the same side (Z1 side) ("ko" shape), or as... Figure 7C The second current path 12 and the third current path 13 shown extend in opposite directions (crank type). However, these are just examples; the busbar 1 is not limited to these shapes. Alternatively, current sensors 40 with different shapes of busbar 1 can be arranged side-by-side.

[0080] Figure 8A It is along Figure 8B A cross-sectional view of the current sensor 40 cut by the XZ plane along the straight line Lz. Figure 8B This is a plan view showing the positional relationship of each part of the current sensor 40, with dashed lines representing the outlines of each part. As shown in the figure, the busbar 1 may also have an exposed portion 14 not covered by the frame 4. By providing the exposed portion 14 in the area opposite to the cooling device 30, the cooling efficiency of the busbar 1 is improved.

[0081] Figure 9A It is along Figure 9B A cross-sectional view of a multiphase current sensor 50 cut by the XZ plane along the straight line Lx. Figure 9B It is along Figure 9A A cross-sectional view of the current sensor 50 cut by the straight line H using the XY plane. Figure 9C This is a plan view showing the outer contours of the various parts of the current sensor 50, represented by dashed lines. The current sensor 50 is a three-phase integrated unit, and when viewed along the X-axis, it is configured such that parts of adjacent busbars 1 overlap. By providing steps in the busbars, the width of the current sensor 50 in the Y-axis direction is reduced.

[0082] Multiple magnetic sensors 3 of the current sensor 50 are arranged in the Y-axis direction (second direction). One end 11a of the first current path 11 in the busbar 1 and the second current path 12 extending from the first end 11a are arranged at different positions in the X-axis direction (first direction) from the other end 11b and the third current path 13 extending from the other end 11b. The first current path 11 has: a first flat portion 111 having one end 11a; a second flat portion 112 having the other end 11b; and an intermediate portion 113 connecting the first flat portion 111 and the second flat portion 112. Moreover, the intermediate portion 113 extends in a manner that intersects the Y-axis when viewed from the Z1 to Z2 direction.

[0083] like Figure 9AAs shown, when the positions of the second current path 12 and the third current path 13 in the X-axis direction are different, the fact that the busbar 1 is configured to be closer to the X1 side than the center of the frame 4 means that the midpoint M of the second current path 12 and the third current path 13 in the X-axis direction is located closer to the X1 side than the center line C of the frame 4.

[0084] like Figure 9A , Figure 9B As shown, the position of the second current path 12 in the X-axis direction of the busbar 1 of the current sensor 50 is different from the position of the third current path 13. More specifically, the busbar 1 bends towards the second flat portion 112 at the connection between the first flat portion 111 and the intermediate portion 113, and bends towards the second flat portion 112 at the connection between the second flat portion 112 and the intermediate portion 113. Furthermore, the magnetic sensors 3 of each phase are configured to face the surface 111S of the first flat portion 111 of the first current path 11, which is on the side of the second flat portion 112 (X2 side). Moreover, as... Figure 9C As shown, in a plan view viewed from the X-axis direction, the second current path 12 of the busbar 1 of one adjacent phase overlaps at least partially with the third current path 13 of the busbar 1 of the other phase. Based on this structure, the size of the current sensor 50 in the Y-axis direction can be reduced by the amount by which the second current path 12 of the busbar 1 of one adjacent phase overlaps with the third current path 13 of the busbar 1 of the other phase.

[0085] like Figure 9B As shown, the positions of the first flat portion 111 of adjacent phase busbars 1 in the X direction are the same, and the positions of the second flat portion 112 are also the same. This structure reduces the increase in size of the current sensor 50 in the X-axis direction. Furthermore, the configuration that the shield 2 and the third current path 13 (second flat portion 112) in the Y direction are in the same position further reduces the increase in size of the current sensor 50 in the X-axis direction.

[0086] The busbar 1 has portions of different heights in the thickness direction (X-axis direction), and the busbar 1 is arranged such that the first flat portion 111 of one phase (the phase on the Y2 side) overlaps with the second flat portion 112 of the other phase (the phase on the Y1 side). According to this structure, the spacing between adjacent current sensors 50 can be reduced.

[0087] like Figure 9BAs shown, when viewed from above the first current path 11 along the Z-axis, the length D1 of the first flat portion 111 in the Y-axis direction (second direction) is greater than the sum of the length D2 of the second flat portion 112 and the length D3 of the middle portion 113 (D1>D2+D3). Thus, by increasing the length D1, the area in the first flat portion 111 through which the measured current flows approximately along the Y-axis direction is widened, enabling high-precision measurement of the current using the magnetic sensor 3.

[0088] exist Figure 9B In this configuration, the middle portion 113 extends in an inclined direction relative to the X-axis direction (first direction), but it can also be configured to extend in a direction parallel to the X-axis direction. However, as described above, the lengths D1 of the first flat portion 111, D2 of the second flat portion 112, and D3 of the middle portion 113 are in the relationship D1>D2+D3, and in order to ensure space for the magnetic sensor 3 to be arranged opposite to the first flat portion 111, the length D2 of the second flat portion 112 is actually the same as the length dimension of the third current path 13 in the Y direction. Therefore, when adopting a structure in which the middle portion 113 extends in a direction parallel to the X-axis direction, considering the insulation between the busbars 1, the size by which the second current path 12 and the third current path 13 can be overlapped in the X-axis direction cannot be too large. However, by configuring the structure to extend in the inclined direction, the second current path 12 of the other phase can be overlapped with the middle portion 113 of the adjacent current sensor 50. Therefore, the overlap between the busbar 1 of one phase and the busbar 1 of the other phase can be increased, and the current sensor 50 can be miniaturized. In addition, without increasing the overlap, the insulation between the adjacent busbars 1 can be obtained more reliably, and it is also easier to handle large currents.

[0089] like Figure 9A and Figure 9B As shown, the third current path 13 is positioned such that the distance between the second current path 12 and the third current path 13 in the X-axis direction (first direction) is greater than the distance between the second current path 12 and the magnetic sensor 3. In other words, the third current path 13 is positioned on the opposite side of the second current path 12, separated by the magnetic sensor 3. Furthermore, the third current path 13 is positioned on the other side (X2 side) of the frame 4, closer to the magnetic sensor 3. By positioning the third current path 13 closer to the other side of the frame 4, it is easier to dissipate the heat generated in the third current path 13 to the other side of the frame 4.

[0090] The third current path 13 and the second flat portion 112 are positioned so as not to overlap with the shield 2 when viewed in the X direction, i.e., along the X-axis. Therefore, the heat generated in the third current path 13 and the second flat portion 112 is not blocked by the shield 2, and can be easily and efficiently dissipated to the other side of the frame 4.

[0091] Furthermore, the third current path 13 and the second flat portion 112 are positioned in the same direction as the shield 2 in the Y direction, that is, they are arranged in an overlapping position when viewed along the X-axis. Therefore, the heat generated in the third current path 13 and the second flat portion 112 is not blocked by the shield 2, and heat can be dissipated to the other side of the frame 4 more efficiently.

[0092] In addition, in use Figure 7A When the cooling device 30 shown is used for cooling, the third current path 13 and the second flat portion 112 can be easily cooled by the cooling device 30 disposed on the other side of the frame 4. In addition, the increase in size of the current sensor 50 in the X-axis direction can be further reduced.

[0093] Figure 10A It is along Figure 10B A cross-sectional view of a modified example of the current sensor 50, where the straight line Lx is cut by the XZ plane. Figure 10B It is along Figure 10A A cross-sectional view of the current sensor 50 cut by the straight line H using the XY plane. Figure 10C These are plan views showing the outer contours of the various parts of the current sensor 50, indicated by dashed lines. As shown in these figures, the current sensor 50 can also be configured such that a portion 14 of the busbar 1 is exposed on the surface of the first current path 11 opposite to the magnetic sensor 3 (X1 side). Furthermore, to prevent the busbar 1 from floating relative to the frame 4, an anchoring structure embedded in the frame 4 can be provided locally at the outer periphery of the exposed portion of the busbar 1. In this modified example, a structure is disclosed that only the first flat portion 111 of the first current path 11 is exposed, but a structure that also exposes the second flat portion 112 is also possible. Such a structure improves heat dissipation and cooling performance.

[0094] Figure 11A It is along Figure 11B A cross-sectional view of the current sensor 60, showing other variations of the straight line Lx cut by the XZ plane. Figure 11B It is along Figure 11A A cross-sectional view of the current sensor 60 cut by the straight line H using the XY plane. Figure 11C This is a plan view showing the outer contours of the various parts of the current sensor 60, represented by dashed lines.

[0095] The busbar 1 of the current sensor 60 has a heat dissipation section 15 opposite to the cooling device 30 in the portion opposite to the magnetic sensor 3. By providing the heat dissipation section 15 in the busbar 1, the cooling efficiency of the cooling device 30 can be improved.

[0096] When viewed from the X-axis direction, the heat dissipation section 15 comprises the portions on both sides of the measured section 151 opposite to the magnetic sensor 3, and has a wide heat dissipation section 152 with a width W2 in the Z-axis direction larger than the width W1 of the measured section 151. A hollow portion 152b with a front-end side opening 152a is formed in the wide heat dissipation section 152, extending from the measured section 151 side, thus functioning as a heat pipe. According to this structure, the surface area of ​​the wide heat dissipation section 152 is increased, making it easier to release heat from the busbar 1 to the cooling device 30, thereby improving cooling efficiency.

[0097] Industrial applicability

[0098] As described above, the present invention can efficiently cool the busbar using a cooling device, and therefore is useful as a current sensor for electric vehicles or hybrid vehicles with large-capacity electric motors.

[0099] Explanation of reference numerals in the attached figures

[0100] 1: Busbar

[0101] 11: First current path

[0102] 11A: One end

[0103] 11b: The other end

[0104] 111: First flat section

[0105] 111S: Surface on the side of the second flat portion

[0106] 112: Second flat section

[0107] 113: Middle section

[0108] 12: Second Current Path

[0109] 13: Third Current Path

[0110] 14: Exposed area

[0111] 15: Heat dissipation section

[0112] 151: Measured part

[0113] 152: Wide heat dissipation section

[0114] 152a: Front side opening

[0115] 152b: Hollow section

[0116] 2: Shielding components

[0117] 3: Magnetic sensor

[0118] 4: Frame

[0119] 4a: Outer shell

[0120] 4b: Cover

[0121] 41: Bossed section

[0122] 42: Heat dissipation recess

[0123] 5: Substrate

[0124] 6: Sealing components

[0125] 7: Radiator

[0126] 8: Nuts

[0127] 9: Bolts

[0128] 10: Measurement Unit

[0129] 20, 40, 50, 60: Current sensors

[0130] 30: Cooling device

[0131] 30a, 30b: Water cooling pipe inlets

[0132] 32: Shielding section

[0133] C: Centerline

[0134] M: Midpoint

[0135] H, Lx, Lz: Lines indicating the location of the cross-section

[0136] S: Sensitivity axis

[0137] D1, D2, D3: Length in the Y-axis direction

[0138] D4: Width of the frame

[0139] W1, W2: Width in the Z-axis direction

Claims

1. A current sensor, cooled by a cooling device, comprising: a busbar; a shield disposed opposite the busbar; a magnetic sensor disposed between the shield and the busbar; and a frame integrally enclosing a portion of the busbar, the shield, and the magnetic sensor, characterized in that, In the first direction in which the busbar, the magnetic sensor, and the shield are arranged, with the side where the busbar is located as one side, the busbar is positioned closer to the center of the frame than the center of the frame. At least one side of the frame is positioned opposite the cooling device. The bus bar has the following features: A first current path extends along a direction having a second directional component, the second direction being orthogonal to the first direction; as well as The second and third current paths extend from one end and the other end of the second direction of the first current path, respectively, along directions having a third component, wherein the third component is orthogonal to the first and second directions. The magnetic sensor is configured opposite to the first current path, and the sensitivity direction of the magnetic sensor is the third direction. Multiple measurement units, consisting of the busbar, the shield, and the magnetic sensor, are arranged in the second direction. The second current path extending from one end of the first current path and the third current path extending from the other end are positioned differently in the first direction. When viewed from the first direction, the second current path of one busbar and the third current path of the other busbar are configured to overlap at least partially.

2. The current sensor as described in claim 1, wherein, The first current path includes: a first flat portion having one end; a second flat portion having the other end; and an intermediate portion connecting the first flat portion and the second flat portion. When viewed from the third direction, the middle portion extends in an inclined direction relative to the first direction.

3. The current sensor as described in claim 2, wherein, The magnetic sensor is configured to face the side of the first flat portion in the first current path that is adjacent to the second flat portion.

4. The current sensor as described in claim 3, wherein, When the first current path is viewed from the third direction, the length of the first flat portion in the second direction is greater than the sum of the length of the second flat portion and the length of the middle portion.

5. The current sensor as described in claim 1, wherein, The busbar has an exposed portion on one side of its surface in the first direction that is not covered by the frame. The exposed portion is opposite to the cooling device.

6. The current sensor as described in claim 5, wherein, The exposed portion is covered by a sealing component that has a higher thermal conductivity than the frame and is also insulating.

7. The current sensor as claimed in claim 1, wherein, The busbar has a heat dissipation section on the portion opposite the magnetic sensor. The heat dissipation section is opposite to the cooling device.

8. The current sensor as claimed in claim 7, wherein, The heat dissipation section, when viewed from the first direction, becomes the portion on both sides of the measured part opposite to the magnetic sensor, and has a wide heat dissipation section that is wider than the measured part.

9. The current sensor as claimed in claim 8, wherein, The wide heat dissipation section has a hollow section with a front side opening.

10. The current sensor as claimed in claim 1, wherein, A radiator is disposed between the busbar and the cooling device on the side of the frame opposite to the cooling device.

11. The current sensor as claimed in claim 1, wherein, A fastening component is provided on the side of the busbar opposite to the cooling device. The fastening component is in contact with the busbar.

12. The current sensor as claimed in claim 1, wherein, The busbar is integrally formed with the frame.

13. The current sensor as claimed in claim 1, wherein, The substrate equipped with the magnetic sensor is connected to the frame via the boss portion of the frame.

14. The current sensor as claimed in claim 1, wherein, The cooling device has a shielding portion on the side opposite to the frame, which has the function of shielding magnetism.

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