current sensor

Abstract

A current sensor is disclosed that can maintain detection accuracy in a circuit with a large current, and achieve miniaturization and low cost. The current sensor (10) includes: a busbar (12) that forms a circuit; a pair of core members (18, 18) that extend above one side (14) of the busbar (12) in the thickness direction toward one side and the other side in the width direction of the busbar (12) and are arranged opposite each other with a gap (16) provided in the central part in the width direction; and a magnetic detector (20) that is arranged in the gap (16) provided in the gap between the pair of core members (18, 18) and the extended ends (22) of each core member (18) that are arranged outside the width direction of the busbar (12) beyond the side edge (24) of the busbar (12) are bent toward the busbar (12).

Description

Technical Field

[0001] This disclosure relates to current sensors. Background Technology

[0002] Patent Document 1 discloses a magnetic detection type current sensor, which is used in vehicles such as electric vehicles and hybrid vehicles. This sensor measures the current value by detecting the magnetic flux generated by the current flowing through the circuit. In this current sensor, to achieve higher accuracy in current measurement, a gap core is arranged around the circuit, formed by cutting a portion of a circular or square wound iron core. A Hall element, acting as a magnetic detector, is inserted into the gap to detect the magnetic field.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2013-113630 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] However, the need to configure a gap core around the circuit, the size of which surrounds the circuit, inevitably leads to the enlargement of the current sensor itself. In particular, due to the increasing current in vehicles in recent years, the circuit itself has also become larger, requiring a correspondingly larger gap core, thus exacerbating the problem. Furthermore, to achieve high-precision magnetic field detection, materials with excellent magnetic properties, such as electromagnetic steel plates and permalloy, are required as the core material. The accompanying increase in size due to the increasing current makes high cost unavoidable.

[0008] Therefore, a current sensor is disclosed that can maintain detection accuracy in circuits with large currents, and can be miniaturized and reduced in cost.

[0009] Methods for solving problems

[0010] The current sensor disclosed herein comprises: a busbar forming a circuit; a pair of core members extending above one side of the busbar in the thickness direction toward one side and the other side in the width direction of the busbar, and disposed opposite to each other with a gap provided in the central portion in the width direction; and a magnetic detector disposed in the gap provided between the pair of core members, the extended ends of each core member being disposed beyond the side edge of the busbar and bent toward the busbar side.

[0011] Invention Effects

[0012] The current sensor disclosed herein can maintain detection accuracy in circuits with large currents, and can be miniaturized and reduced in cost. Attached Figure Description

[0013] Figure 1 This is a perspective view showing the current sensor of Embodiment 1 in a state of being mounted on a printed circuit board.

[0014] Figure 2 yes Figure 1 The top view of the current sensor shown.

[0015] Figure 3 yes Figure 2 Sectional view III-III in the diagram. Detailed Implementation

[0016] <Description of embodiments of this disclosure>

[0017] First, embodiments of this disclosure will be described.

[0018] In the current sensor disclosed herein, (1) It comprises: a busbar that forms a circuit; a pair of core members that extend above one side of the busbar in the thickness direction toward one side and the other side in the width direction of the busbar and are disposed opposite each other with a gap provided in the central portion in the width direction; and a magnetic detector disposed in the gap provided in the gap between the pair of core members, the extended ends of each of the core members being disposed outside the width direction of the busbar beyond the side edge of the busbar and bent toward the busbar.

[0019] According to this current sensor, a pair of core members are disposed on one side of the busbar constituting the circuit in the thickness direction, and are arranged opposite each other with a gap in the width direction. Thus, a magnetic detector can be disposed on one side of the busbar in the thickness direction, in the gap between the pair of core members. Furthermore, the extended ends of each core member, disposed beyond the side edge of the busbar in the width direction, bend towards the busbar. This utilizes the magnetic focusing effect of the pair of core members, enabling high-precision detection of the magnetic field even when no core member is disposed on the other side of the busbar in the thickness direction, in regions with high current values ​​when the current flowing through the busbar is high. Moreover, with this pair of core members, it is unnecessary to place core members on the other side of the busbar in the thickness direction. Therefore, compared to the existing structure that uses a gap core formed by cutting a portion of a circular or square wound iron core around the circuit, miniaturization of the core members themselves and the current sensor as a whole, or reduction in material costs, can be achieved. Furthermore, even in regions with high current values ​​energizing the busbar, magnetic field detection can be performed with sufficient accuracy, even when using materials such as iron as the core components. As a result, costs can be reduced without the need for materials such as electromagnetic steel sheets or permalloy. Therefore, the current sensor based on this method can maintain detection accuracy in circuits with high current energization, while also achieving miniaturization and low cost.

[0020] Furthermore, the current value energized to the busbar of the current sensor of this method can be applied to a high current range, approximately 100A to 2000A.

[0021] (2) In (1) above, it is preferable that the extended end of each core member protrudes downward beyond the face on the other side of the busbar in the thickness direction. Since the extended end of each core member protrudes downward beyond the busbar, the magnetic focusing effect of a pair of core members can be utilized more effectively, thereby improving the detection accuracy of the current sensor. Moreover, since it is not necessary to arrange the core members in a manner that covers the busbar from below and connects the extended ends of a pair of core members to each other, miniaturization / cost reduction compared to conventional structures can be achieved.

[0022] (3) In (1) or (2) above, it is preferable that each of the core members is configured as an L-shape having a parallel portion and an extended end, the parallel portion extending parallel to the busbar, and the extended end bending in a direction orthogonal to the parallel portion. Since each core member disposed around the busbar is configured as an L-shape with the parallel portion and the extended end orthogonally connected, miniaturization of the core member and the current sensor as a whole can be achieved, and the magnetic focusing effect of the core member can be improved.

[0023] (4) In (3) above, preferably, the magnetic detector comprises: a printed substrate; and a magnetic sensor mounted on a first surface of the printed substrate, the magnetic sensor being disposed in the gap, and on the other hand, the parallel portion of each of the core members is placed on the first surface of the printed substrate, and the extended end of each of the core members protrudes downward beyond the second surface of the printed substrate, and the extended end of at least one of the core members is inserted through a through hole in the printed substrate and protrudes downward beyond the second surface of the printed substrate, and the busbar is stacked on the second surface of the printed substrate.

[0024] By mounting parallel portions of the core members on the first surface of a printed circuit board (PCB) serving as the mounting surface for the magnetic sensor, each core member can be held on the PCB, and the magnetic sensor can be stably positioned between a pair of core members. The extended ends of each core member protrude downwards beyond the second surface of the PCB, and a busbar is stacked on the second surface of the PCB. This suppresses the overall height dimension of the current sensor (the dimensions of the busbar and the PCB in the thickness direction), and improves the magnetic focusing performance and assembly stability of the pair of core members. Furthermore, since the extended end of at least one core member protrudes downwards beyond the second surface of the PCB through a through-hole, the positioning and retention of the core member relative to the PCB are also improved.

[0025] (5) Based on any one of (1) to (4) above, it is preferred that each of the core components is formed of an iron-based material. This is because even if an iron-based material is used to construct the core component, the magnetic field in the high current region can be detected with high precision, and further cost reduction can be achieved.

[0026] <Detailed description of the embodiments of this disclosure>

[0027] The following description, with reference to the accompanying drawings, illustrates specific examples of the current sensor of this disclosure. It should be noted that this disclosure is not limited to these examples, but rather to the modifications shown in the claims, which are intended to encompass all changes within the meaning and scope equivalent to the claims.

[0028] <Implementation Method 1>

[0029] The following uses Figures 1 to 3 The current sensor 10 according to Embodiment 1 of this disclosure will be described. This current sensor 10 is installed in, for example, a junction box (electrical connection box) inside the battery pack of an electric vehicle or hybrid vehicle, and measures the current flowing in the junction box (JB). Furthermore, in a vehicle, the current sensor 10 can be configured in any orientation; hereinafter, "above" refers to... Figure 3 Above and below refer to Figure 3 The bottom and left side refer to Figure 2 The upper part and the right side refer to the middle. Figure 2 Below, in front refers to Figure 2 The left and the back refer to Figure 2 The explanation will be provided on the right side of the diagram. Additionally, regarding multiple identical components, sometimes only some components are labeled, while the labels are omitted for the others.

[0030] <Current Sensor 10>

[0031] The current sensor 10 includes: a busbar 12 forming a circuit; and a pair of core members 18, 18, which extend above the upper surface 14 of the busbar 12 in the thickness direction (vertical direction) and toward one side and the other side in the width direction (left-right direction), and are arranged opposite each other in the left-right direction through a gap 16 provided in the central part of the width direction (left-right direction). Furthermore, in the current sensor 10, a magnetic detector 20 is disposed in the gap 16 between the opposing gaps of the pair of core members 18, 18.

[0032] <Bus Bar 12>

[0033] Busbar 12 is disposed in JB to form a circuit, for example. Both ends of busbar 12 are connected to electrical components in JB, or one end of busbar 12 is exposed to the outside of JB and connected to external electrical equipment, etc. Busbar 12 is formed, for example, of a metal with excellent conductivity, such as copper (including copper alloys). In embodiment 1, busbar 12 has a generally rectangular cross-section and extends generally straight in the front-back direction.

[0034] <Core Component 18>

[0035] As described above, each core member 18 extends toward one side and the other side of the busbar 12 in the width direction (left-right direction) across the gap 16. In addition, in each core member 18, the extension end 22, which is the end of the portion extending toward one side and the other side in the left-right direction, is disposed beyond the side edge 24 of the busbar 12 and is located further outward in the left-right direction than the side edge 24, and these extension ends 22 are bent toward the lower side that becomes the side of the busbar 12.

[0036] In Embodiment 1, the extended end 22 of each core member 18 protrudes downward beyond the lower surface 26, which is the side opposite to the thickness direction of the busbar 12. More specifically, each core member 18 has a parallel portion 28 that extends parallel to the busbar 12. That is, the parallel portion 28 in each core member 18 extends in the horizontal direction (a direction orthogonal to the vertical direction), such as... Figure 2As shown in the top view, it extends outward from the middle portion in the left-right direction of the busbar 12. Furthermore, each extending end 22 extends downward in a curved manner from the outer left-right end of each parallel portion 28, perpendicular to the parallel portion 28. As a result, as... Figure 3 As shown in the longitudinal section, each core member 18 has a generally L-shaped longitudinal section, and each core member 18 has a specified front-to-back dimension.

[0037] In particular, in Embodiment 1, each parallel portion 28 and each extended end portion 22 is rectangular in shape when viewed from above. Furthermore, each parallel portion 28 and each extended end portion 22 has equal front-to-back dimensions, and each extended end portion 22 has a smaller left-to-right dimension than each parallel portion 28. The height dimension (vertical dimension) of the parallel portion 28 is not limited; for example, it can be set to be approximately equal to or slightly larger than the height dimension of the magnetic sensor 39 described later in the magnetic detector 20. That is, the upper end surface of each parallel portion 28 can, for example, be positioned slightly higher than the upper end surface of the magnetic sensor 39.

[0038] In other words, on both sides of the busbar 12 in the left-right direction, a pair of extending ends 22, 22 are provided on the outer side of the side edges 24, 24 of the busbar 12 in the left-right direction, extending in a direction orthogonal to the left-right direction. Figure 3 The longitudinal section shown extends vertically. Furthermore, each of these extended ends 22 has a parallel portion 28 extending inwardly in the left-right direction at its upper end. The left-right inner surfaces 30 of these parallel portions 28 are spaced apart by a predetermined distance D (see reference). Figure 3 The gaps between these left-right inner surfaces 30, 30 are gaps 16 provided between each core member 18 in the central portion of the busbar 12 in the width direction (left-right direction). In Embodiment 1, the left-right inner surfaces 30 of each core member 18 are located further inward in the left-right direction than the two side edges 24, 24 of the busbar 12. That is, in the vertical projection, the two side edges 24, 24 of the busbar 12 partially overlap the left-right dimension E (refer to the parallel portion 28 in each core member 18) with respect to the parallel portion 28 in the core member 18. Figure 3 The amount of ).

[0039] Furthermore, in Embodiment 1, the lower end face 32 of each extension end 22 extends in a direction orthogonal to the vertical direction, and each lower end face 32 extends parallel to the lower surface 26 at a location lower than the lower surface 26 of the busbar 12. In summary, the extension end 22 of each core member 18, for example, does not bend inward in the left-right direction towards the side of the busbar 12, and the lower end of the extension end 22 of each core member 18 is open, allowing the busbar 12 to be exposed downward through the lower opening 34 formed by the lower ends of each extension end 22. That is, in Embodiment 1, the lower part of the busbar 12 is not covered by each core member 18.

[0040] The material of each core component 18 formed into the above shape is not limited as long as it is metal, but it is preferably made of inexpensive ferrous materials. As ferrous materials, it can be any of pure iron with low carbon content, cast iron with high carbon content, or steel with a carbon content in between, or it can be an alloy iron containing other elements such as nickel, chromium, and molybdenum. Each core component 18 can be formed by shaping the above-mentioned material into a specified shape, but it can also be formed using, for example, scrap material generated when forming other metal components.

[0041] <Magnetic Detector 20>

[0042] As described above, a magnetic detector 20 is disposed in the gap 16 between each core member 18. In Embodiment 1, the magnetic detector 20 includes a printed circuit board 36 and a magnetic sensor 39 mounted on the first surface, i.e., the upper surface 38, of the printed circuit board 36. The magnetic sensor 39 in the magnetic detector 20 is disposed in the gap 16 between each core member 18.

[0043] <Printed substrate 36>

[0044] The printed circuit board 36 extends horizontally, and a circuit (not shown) is printed on its upper surface 38. This circuit is electrically connected to the magnetic sensor 39, thereby mounting the magnetic sensor 39. Through holes 40 are formed on both sides of the mounting location of the magnetic sensor 39 in the printed circuit board 36 in the left-right direction. These through holes 40 penetrate the printed circuit board 36 in the thickness direction (vertical direction). Each through hole 40 is rectangular in top view, sized to allow the extended ends 22 of each core member 18 to pass through.

[0045] Specifically, each through-hole 40 has a front-to-back dimension equal to or slightly smaller than that of each extension end 22, and a left-to-right dimension slightly larger than that of each extension end 22. Thus, each extension end 22 of each core member 18 can be inserted into each through-hole 40 from above, and each core member 18 is assembled onto the printed circuit board 36 by means of its extension ends 22 being inserted into each through-hole 40. Furthermore, with each core member 18 assembled onto the printed circuit board 36, the parallel portion 28 of each core member 18 rests on the first surface (upper surface 38) of the printed circuit board 36. Additionally, each extension end 22 inserted into each through-hole 40 protrudes downward beyond the second surface, i.e., the lower surface 42, of the printed circuit board 36.

[0046] Furthermore, the aforementioned busbar 12 is disposed below the printed circuit board 36. In Embodiment 1, the second surface (lower surface 42) of the printed circuit board 36 is stacked with the upper surface 14 of the busbar 12. Also, as previously described, the extended ends 22 of each core member 18 inserted into each through hole 40 of the printed circuit board 36 protrude to a position lower than the lower surface 26 of the busbar 12.

[0047] Furthermore, the printed substrate 36 can be a known printed substrate. That is, the printed substrate 36 can be a flexible substrate that can be flexibly deformed, or it can be a rigid substrate with a certain degree of deformation rigidity.

[0048] Furthermore, when assembling each core component 18 onto the printed circuit board 36, the method of fixing the printed circuit board 36 and each core component 18 is not limited, as long as the structure prevents each core component 18 from detaching from the printed circuit board 36. That is, the parallel portions 28 of each stacked core component 18 can be bonded to the printed circuit board 36, or the front-rear dimensions of each extended end 22 and each through hole 40 can be equal, and each extended end 22 can be inserted into each through hole 40 in a pressed-in state. Alternatively, when the current sensor 10 is disposed within the JB (not shown), each core component 18 and the printed circuit board 36 can be fixed to the housing of the JB, and each core component 18 and the printed circuit board 36 can also be fixed to each other via the housing of the JB.

[0049] <Magnetic Sensor 39>

[0050] As for the magnetic sensor 39, there are no limitations as long as it is a magnetic field detection type, and a known magnetic sensor can be used. That is, the magnetic sensor 39 uses the magnetic field (magnetic field) generated by the current flowing in the busbar 12 to detect the current value, and can be a cored magnetic sensor or a coreless magnetic sensor, specifically a Hall IC, etc.

[0051] In Embodiment 1, a magnetic sensor 39 is disposed in the center of the gap 16 between each core component 18 in the left-right direction. In particular, in Embodiment 1, the magnetic sensor 39 is located in the center part of the width direction (left-right direction) of the busbar 12.

[0052] In the current sensor 10 described above, when a current flowing from front to rear through the busbar 12, Figure 3 In the longitudinal sectional view, a clockwise magnetic circuit R is formed around the busbar 12 (in Figure 3 (Diagram shown with double-dotted lines). Here, core members 18 made of ferro-based material are arranged on the left and right sides of the busbar 12. By focusing the magnetism of each core member 18, the magnetic circuit R is formed into a ring along each core member 18. In particular, in Embodiment 1, the current sensor 10 detects the magnetic field in the high-current region. A high current flows through the busbar 12, so that even if there are gaps such as the lower opening 34 and the gap 16 in each core member 18, the ring-shaped magnetic circuit R can be stably formed. As a result, the current value corresponding to the strength of the magnetic field can be detected by the magnetic sensor 39 arranged in the gap 16 of each core member 18.

[0053] In addition, the current sensor 10 disclosed herein is suitable for detecting magnetic fields in high current regions, for example, the current value flowing through the busbar 12 is preferably in the range of 100A to 2000A.

[0054] According to Embodiment 1 of the current sensor 10 with the above-described structure, each core member 18 is provided above the busbar 12, and a magnetic sensor 39 from the magnetic detector 20 is disposed in the gap 16 between the core members 18. Each core member 18 has an extension end 22 extending downward at a position further outward in the left-right direction than the two side edges 24, 24 of the busbar 12. In short, the upper, left, and right sides of the busbar 12 are covered by the core members 18. For example, when a current flows through the busbar 12 in a high-current region, a ring-shaped magnetic circuit R is formed along the core members 18 by the magnetic focusing effect of the core members 18. As a result, the current value flowing through the busbar 12 can be detected by the magnetic sensor 39 disposed in the gap 16 between the core members 18. That is, in the detection of current in a high-current region, it is only necessary to provide relatively small core members 18 with the above-described shape around the busbar 12, which can achieve miniaturization and cost reduction of the current sensor 10 compared with the conventional structure.

[0055] The extended ends 22 of each core component 18 protrude downwards from the lower surface 26 of the busbar 12. As a result, the extended ends 22 can cover the two side edges 24, 24 of the busbar 12 from the left and right directions, and a stable annular magnetic circuit R can be formed around the busbar 12 when energized.

[0056] Each core member 18 is configured in an L-shape having a parallel portion 28 extending parallel to the busbar 12 and an extended end 22 bending in a direction orthogonal to the parallel portion 28. As a result, each core member 18 can stably cover the three sides around the busbar 12, and a more stable annular magnetic circuit R can be formed around the busbar 12 when energized.

[0057] The printed circuit board 36 has through holes 40. By inserting the extended ends 22 of each core member 18 through the through holes 40, the parallel portions 28 of each core member 18 are stacked with the upper surface 38 of the printed circuit board 36. Additionally, a busbar 12 is stacked on the lower surface 42 of the printed circuit board 36, with each extended end 22 extending to a position below the lower surface 26 of the busbar 12. Thus, the busbar 12 and each core member 18 can be fixed via the printed circuit board 36, and each core member 18 can be precisely positioned around the busbar 12.

[0058] Each core component 18 can be any magnetic material and is not limited thereto, but it is preferably made of inexpensive ferrous materials. In particular, since each core component 18 is relatively small, scrap materials generated during the formation of other metal components can also be utilized. As a result, cost reduction can be achieved compared to using electromagnetic steel sheets, permalloy, etc.

[0059] <Variation Example>

[0060] The above detailed description of Embodiment 1 is provided as a specific example of this disclosure, but this disclosure is not limited to this specific description. Modifications and improvements within the scope of achieving the purpose of this disclosure are included in this disclosure. For example, the following modifications of the embodiment are also included within the technical scope of this disclosure.

[0061] (1) The extension dimension (vertical dimension) of the extension end is not limited. In the above embodiment, the lower end face 32 of each extension end 22 is located below the lower surface 26 of the busbar 12, but it may also be located above the lower surface of the busbar. In addition, the extension end preferably has a certain extension dimension, for example, the lower end face of the extension end is preferably located below the lower surface of the printed circuit board.

[0062] (2) In the above embodiment, each extension end 22 extends straight along the vertical direction, but a portion protruding inward in the left-right direction may also be provided at the lower end of each extension end. In this case, the inner surface of the portion protruding inward in the left-right direction at the lower end of the extension end is preferably located outside the left-right direction than the side edge of the busbar. When a portion protruding inward in the left-right direction is provided at the lower end of the extension end, it is also preferable that the busbar is not covered by this portion and is open downward. It should be noted that, in the case described above, by forming a through hole in the printed circuit board that is larger than the lower end face of the extension end when viewed from above, each core component can be assembled onto the printed circuit board from above.

[0063] (3) In the above embodiment, the magnetic sensor 39 is disposed in the central part of the busbar 12 in the width direction (left and right direction). However, as long as the magnetic sensor is inside the gap, it can also be disposed to a certain extent offset from the central part of the busbar in the width direction to the left and right direction.

[0064] (4) In the above embodiment, a pair of through holes 40, 40 are provided on the left and right sides of the mounting position of the magnetic sensor 39 on the printed circuit board 36 and the extension ends 22 of each core member 18 are inserted through them, but it is not limited to this method. For example, the extension end of at least one core member may not be inserted through the through hole of the printed circuit board, or it may extend in the vertical direction at a position outside the left and right direction of the printed circuit board.

[0065] (5) In the above embodiment, the printed circuit board 36 is stacked on the upper surface 14 of the busbar 12, and the magnetic sensor 39 and each core component 18 are stacked from above the printed circuit board 36, but this is not a limitation. The current sensor 10 of Embodiment 1 may also be configured upside down, or the printed circuit board may be stacked on the lower surface of the busbar, and the magnetic sensor and each core component may be stacked from below the printed circuit board. In addition, the components stacked to each other are not limited to direct stacking, and may also be stacked indirectly with gaps or other components in between.

[0066] Label Explanation

[0067] 10 Current Sensor

[0068] 12 busbars

[0069] 14. Top surface (the side of the busbar in the thickness direction)

[0070] 16 gaps

[0071] 18-core components

[0072] 20 Magnetic Detectors

[0073] 22 Extended end

[0074] 24 Lateral edge

[0075] 26. Lower surface (the surface on the opposite side of the busbar in the thickness direction)

[0076] 28 Parallel Department

[0077] 30° inner surface

[0078] 32 Lower end face

[0079] 34. Lower opening

[0080] 36 Printed substrate

[0081] 38. Upper surface (first surface)

[0082] 39 Magnetic Sensor

[0083] 40 through holes

[0084] 42 Lower surface (second surface)

[0085] R-magnetic circuit.

Claims

1. A current sensor, wherein, have: Busbars form a circuit; A pair of core members extend above one side of the busbar in the thickness direction toward one side and the other side in the width direction of the busbar, and are arranged opposite each other with a gap provided in the central portion in the width direction. and A magnetic detector is disposed in the gap between the relative gaps of the pair of core members. The extended ends of each of the core members, which are disposed outside the width direction of the plate beyond the side edge of the busbar, are bent toward the side of the busbar.

2. The current sensor according to claim 1, wherein, The extended end of each of the core components protrudes downwards from the face on the other side of the busbar in the thickness direction.

3. The current sensor according to claim 1 or claim 2, wherein, Each of the core components is configured as an L-shape having a parallel portion and an extended end, the parallel portion extending parallel to the busbar, and the extended end bending in a direction orthogonal to the parallel portion.

4. The current sensor according to claim 3, wherein, The magnetic detector comprises: a printed circuit board; and a magnetic sensor mounted on a first surface of the printed circuit board. The magnetic sensor is disposed in the gap. Furthermore, the parallel portions of each core member are placed on the first surface of the printed circuit board, and the extended ends of each core member protrude downwards beyond the second surface of the printed circuit board. At least one of the core components has its extended end inserted through a through hole in the printed circuit board and protruding downward beyond the second surface of the printed circuit board. The busbar is stacked on the second surface of the printed substrate.

5. The current sensor according to claim 1 or claim 2, wherein, Each of the core components is formed of an iron-based material.

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