JP2013113630A - Current detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a current detector which measures current values in many kinds of measurement areas where areas of measured current values greatly differ with great sensitivity, is downsizable, and lowers costs.SOLUTION: The current detector is provided with: a magnetic shield member 11 formed into a nearly U-shaped cross section of a magnetic material; an internal shield member 12 placed in a nearly U-shaped form as a whole by approximating end parts of a pair of split members 12A and 12B formed into nearly L-shaped cross sections of magnetic materials inside the nearly U-shaped form of the magnetic shield member 11; and a plurality of magnetic detecting means 13 placed in a lamination direction of a current path 20 and the internal shield member 12 in a gap between the end parts of the split members 12A and 12B.

Description

  The present invention relates to a current detection device that detects the value of a current flowing in a current path of a motor, such as an electrical component of an automobile, by using magnetic detection means provided in the vicinity of the current path.

  2. Description of the Related Art Conventionally, a current detection device is used to detect a current flowing in a current path (for example, a bus bar) that connects an in-vehicle battery and a vehicle electrical component. For example, as shown in Patent Document 1, the current detection device includes a ring-shaped core, a magnetic gap formed by opening a part of the core, and a Hall element disposed in the magnetic gap. In this configuration, a current value flowing in a current path inserted through the ring-shaped core is detected by a Hall element arranged in the magnetic gap.

  In this current detection device, when a magnetic field is generated in the ring-shaped core due to the current flowing in the current path, the Hall element in the magnetic gap generates a voltage (Hall voltage) due to the Hall effect corresponding to the magnetic field. At this time, the core functions to strengthen the magnetic field generated by the current flowing in the current path. The Hall voltage generated by the Hall element corresponds to the strength of the magnetic field in the core, and also corresponds to the current value flowing in the current path that generates the magnetic field, so that the current value can be detected.

JP 2007-155400 A

  By the way, recently, an electric vehicle (EV), a hybrid vehicle (HEV), a plug-in hybrid vehicle (PHV) and the like have been increased in current. However, a conventional current detection device is generally configured to detect a current value in one type of measurement region. For example, two types of current values of a large current and a small current can be increased with the same device. It was difficult to detect the sensitivity.

  Under such circumstances, when current values are measured for two different measurement regions having greatly different current values, it is necessary to prepare dedicated current detection devices for each. As a result, a large amount of installation space is required and the cost is increased.

  Thus, for example, a single current detection device having a configuration in which two types of sensors for large current and small current are mounted can be considered. In that case, the sensor for the large current has a larger sensor size than the sensor for the small current, so an extra installation space is required, and an increase in size is inevitable. In addition, since it is necessary to dispose such a large-sized current detection device with respect to one current path, it is difficult to install the current detection device particularly in a limited space such as an automobile.

  The present invention has been made in view of the above-described circumstances, and the purpose of the present invention is to provide high sensitivity to current values in a plurality of types of detection regions that have greatly different measurement current value detection regions, such as for large currents and small currents. It is an object of the present invention to provide a current detection device that can be measured by the above-described method and can be reduced in size and cost.

In order to achieve the above-described object, the current detection device according to the present invention is characterized by the following (1) to (4).
(1) With respect to a current path formed of a magnetic material and having a substantially U-shaped cross section with respect to a current path in which three of the four vertical and horizontal surfaces are surrounded by the substantially U-shaped cross section, A magnetic shielding member installed transversely,
Inside the substantially U-shaped inside of the magnetic shielding member, the ends of a pair of divided members formed in a substantially L-shaped cross section with a magnetic material are placed close to each other, and arranged as a whole in a substantially U-shaped cross section. An internal shield that is installed transversely with respect to the direction in which the current of the current path flows with respect to the current path in which three of the four vertical and horizontal faces different from the three faces are surrounded by the substantially U-shape. Members,
A plurality of magnetic detection means arranged in the stacking direction of the current path and the inner shielding member in the gap between the end portions of the split member, and having different detectable ranges of the magnitude of magnetic flux density or the strength of magnetic field; ,
Having provided.
(2) In the current detection device according to (1) above,
The gap is located at the center in the width direction of the current path.
about.
(3) A current path formed of a magnetic material and having a substantially U-shaped cross section with respect to a current path in which three of the four vertical and horizontal surfaces are surrounded by the substantially U-shaped cross section in the direction of current flow in the current path. A magnetic shielding member installed transversely,
The three surfaces of the four vertical and horizontal surfaces in the cross-section, which are formed in a substantially U-shaped cross-section with a magnetic material, and an opening is formed in a surface located in the center, inside the substantially U-shaped of the magnetic shielding member. An internal shielding member installed transversely to the direction in which the current of the current path flows with respect to the current path surrounded by the substantially U-shape on another three surfaces different from
A plurality of magnetic detection means arranged in the stacking direction of the current path and the internal shielding member in the opening of the internal shielding member and having different detectable ranges of the magnitude of the magnetic flux density or the strength of the magnetic field;
Having provided.
(4) In the current detection device according to (3) above,
The opening is located in the center in the width direction of the current path,
about.

According to the current detection device having the configuration (1), it is possible to measure the current values in a plurality of types of measurement regions having greatly different measurement current value detection regions with high sensitivity. In addition, as compared with the conventional one, it is only necessary to additionally install an internal shielding member and a plurality of magnetic detection means inside the magnetic shielding member, so that it is possible to reduce the size and cost. .
In addition, according to the current detection device having the configuration (2), the gap is provided in the central portion of the current path, so that magnetic detection with higher accuracy is possible.
Further, according to the current detection device having the configuration (3), as in the current detection device having the configuration (1), currents in a plurality of types of measurement regions in which the detectable range of the measurable current value is significantly different. The value can be measured with high sensitivity. In addition, as compared with the conventional one, it is only necessary to additionally install an internal shielding member and a plurality of magnetic detection means inside the magnetic shielding member, so that it is possible to reduce the size and cost. .
In addition, according to the current detection device having the configuration (4), the opening is provided in the central portion of the current path, so that magnetic detection with higher accuracy is possible.

  According to the present invention, it is possible to measure with high sensitivity current values in a plurality of types of measurement regions in which measurement current value detection regions are significantly different. In addition, as compared with the conventional one, it is only necessary to additionally install an internal shielding member and a plurality of magnetic detection means inside the magnetic shielding member, so that it is possible to reduce the size and cost. .

  The present invention has been briefly described above. Further, details of the present invention will be further clarified by reading through the modes for carrying out the invention described below with reference to the accompanying drawings.

FIG. 1 is a partially exploded perspective view of a current detection device according to an embodiment of the present invention. FIG. 2 is a front view of the current detection device shown in FIG. 3 is a cross-sectional view taken along line III-III in the current detection device shown in FIG. FIG. 4 is an explanatory diagram showing a magnetic flux passing state with respect to the first and second sensor portions which are a plurality of magnetic detection means provided in the gaps of the internal shielding member of the current detection device shown in FIG. FIG. 5 is a plan view showing a current detection device according to a modification of the present invention, the type having a detection part as an opening.

  Hereinafter, a preferred embodiment of a current detection device according to the present invention will be described with reference to the accompanying drawings. In the present embodiment, a Hall element is employed as a magnetic detector that detects the strength of the magnetic field generated by the current flowing through the current path.

  The current detection device 10 of the present embodiment is for detecting the current value of a conductor member (hereinafter referred to as a “bus bar” made of a plate-like conductive plate) 20 serving as a current path. A base block (not shown) as a housing formed of a dielectric material forming the outer shape of the detection device 10, a magnetic shielding member 11 installed on the upper surface of the base block, and an inner side of the magnetic shielding member 11 An internal shielding member 12 that is installed and surrounds the bus bar 20 serving as a current path from the outside, and a magnetic detection means 13 that is disposed in a gap G described later that constitutes a detection unit of the internal shielding member 12 are provided.

  The magnetic shielding member 11 is formed of an appropriate magnetic material and has a substantially U-shaped cross section, and is installed in a state where the upper side (Y direction) is open with respect to a base block (not shown). That is, the magnetic shielding member 11 according to the present invention has three directions (± X direction and -Y direction) out of the four directions along the entire circumference of the bus bar 20 serving as a current path, that is, the direction along the XY plane. Is installed transversely to the Z direction in which the current I flows. That is, it is installed in the ± X direction orthogonal to the length (Z) direction of the bus bar 20. In other words, the bus bar 20 is configured to be installed in a non-contact state on the magnetic shielding member 11 directly above the floor surface.

  The internal shielding member 12 is composed of a pair of divided members 12A and 12B each formed of an appropriate magnetic material and having a substantially L-shaped cross section, and has a generally U-shaped cross section as a whole. The divided members 12A and 12B, which are the internal shielding members 12, have cross sections as a whole, with the end portions of the divided members 12A and 12B adjacent to each other holding a predetermined gap G inside the substantially U-shaped inside of the magnetic shielding member 11. Are arranged in a U shape. Further, unlike the magnetic shielding member 11, the inner shielding member 12 is surrounded by three plane directions (ie, ± X direction and + Y direction) including the remaining one plane direction opened with respect to the bus bar 20. Installed at. However, with respect to the direction of the current I flowing through the bus bar 20, in the same state as the magnetic shielding member 11, that is, transverse to the length (Z) direction of the bus bar 20, that is, the X direction perpendicular thereto. Installed. That is, the internal shielding member 12 is installed in a non-contact state with respect to the bus bar 20 immediately above the upper surface thereof.

  The pair of divided members 12A and 12B constituting the internal shielding member 12 are formed in the same dimensions so that the corresponding parts are mirror-symmetric with each other, whereby a gap G is formed in the central portion of the bus bar 20. It is formed. The gap G is formed over the entire length W from the one end side to the other end side in the length direction of the internal shielding member 12. In the present embodiment, the case where the gap G is formed will be described. However, for example, as illustrated in FIG. 5, a configuration in which an opening S is formed on a surface located at the center of the internal shielding member 14 may be used. Absent.

  The magnetic detection means 13 is composed of a plurality of detection ranges having different detection ranges of the magnetic flux density B corresponding to the current I to be measured (or may be the strength of the magnetic field). Corresponding to the gap G which becomes, it is installed three-dimensionally in a state of being stacked vertically (vertical direction in FIG. 2). For example, the magnetic detection means 13 of the present embodiment is mounted on both the front and back surfaces of a printed circuit board 30 made of a dielectric, for example, a wiring board disposed in a state of covering the gap G from above as shown in FIG.

  That is, the magnetic detection means 13 includes a first sensor unit 13A that can detect the magnitude of the magnetic flux density B (or the strength of the magnetic field) corresponding to a large current, and the magnetic flux density B corresponding to a small current. The second sensor unit 13B is a target that can detect the size (or the strength of the magnetic field). Note that the magnetic flux density B and the magnetic field strength H are well known by the relationship of B = μH (where μ is the magnetic permeability), which is an auxiliary formula of the well-known Maxwell equation, whichever is used. Good.

  Each of the first sensor unit 13A and the second sensor unit 13B of the present embodiment uses a Hall element that detects the magnitude of the magnetic flux density B or the strength of the magnetic field using a known Hall effect. Yes. Incidentally, these sensor parts 13A and 13B are composed of physical properties with different detection sensitivities.

  Further, these sensor units 13A and 13B reliably sense the magnetic flux Φ. Therefore, it is preferable to increase the size in the direction perpendicular to the direction of the magnetic flux Φ, that is, to have a tall structure so that the magnetic flux Φ per unit area can penetrate as much as possible. Note that these are connected to a control unit (not shown) mounted on the printed circuit board 30 or a control unit (not shown) installed at an appropriate site by a wiring (not shown). As a result, a predetermined calculation process is performed in accordance with the detection signal input from each Hall element to the control unit, thereby detecting a desired current value flowing through the bus bar 20 near the site where the magnetic detection means 13 is installed. It is like that.

  The magnetic detection means 13 of the present invention is not limited to a Hall element.

Next, the operation of this embodiment will be described.
For example, when a current flows through the bus bar 20, a magnetic field is generated around the bus bar 20, and a magnetic flux density B corresponding to the strength of the magnetic field is generated. Depending on the magnetic flux density B, a magnetic path R (see FIG. 2) is formed inside the inner shielding member 12, but as shown in FIG. 4, the interior facing the gap G, which is the terminal portion of the magnetic path R, is formed. A magnetic flux, that is, a flow of magnetic flux Φ is generated between both ends 12C and 12D of the shielding member 12.

  Accordingly, the first sensor unit 13A and the second sensor unit 13B, which are the magnetic detection means 13, respectively correspond to the density of the magnetic flux Φ penetrating through the first sensor unit 13A and the second sensor unit 13B, that is, the magnetic field strength corresponding to the value of the magnetic flux density B. Thus, an electric field, that is, a hall electric field is generated.

  In this way, the detected electric field, that is, the voltage is output as a detection signal from each Hall element, which is the first sensor unit 13A and the second sensor unit 13B, to a control unit (not shown). In the control unit, the detection signal is amplified by the amplifier circuit, and a voltage value having a value proportional to the detected magnetic field strength is output. That is, the current value flowing through the bus bar 20 is detected based on the output from the Hall element.

Here, for example, when the current value I flowing through the bus bar 20 that is a current path is a large current I ₁ , the first sensor unit having a highly sensitive magnetic characteristic corresponding to the detectable region of the current value I _1. Hall element 13A is surely the intensity B ₁ of the magnetic field corresponding to the large current value can be detected with high sensitivity.

On the other hand, when the current value I flowing through the bus bar 20 that is the current path is a small current I ₂ , the second sensor unit 13B having high-sensitivity magnetic characteristics corresponding to the detectable region of the current value I ₂ . Hall element, ensures that the magnetic field corresponding to the small current value intensity B ₂ can be detected with high sensitivity.

  Therefore, as described above, according to the current detection device 10 according to the present embodiment, a large current and a small current flowing in the bus bar 20 can be used without using two, two types of high-sensitivity current detection devices. Both current values can be detected with high sensitivity.

  Moreover, according to the present embodiment, in one conventional current detection device, the small internal shielding member 12 and the first sensor portion 13A or the second sensor portion of another magnetic detection means 13 having different detection regions. It is only necessary to add any of 13B. In other words, two types of current value detection can be realized by adding only two components. As a result, it is possible to reduce the size and cost as compared with the case of using two high-accuracy current detection devices.

  In addition, in the case of a conventional current detection device, a large measurement error occurs when a current value that deviates from the current detectable region happens to flow, or when a current value that greatly deviates from the detectable region is measured, There was a risk that the needle would swing off. However, according to the current detection device 10 according to the present embodiment, such a trouble can be solved.

  Further, in the present embodiment, as described above, the inner shielding member 12 and the first sensor portion 13A or the second sensor portion 13B of another magnetic detection means having a different detection area are disposed inside the magnetic shielding member 11. You only need to install one of them. For this reason, since the external dimensions are the same as the conventional one, it can be installed at the same installation location as the conventional one. Moreover, in terms of weight, it is not necessary to increase the weight as much as a unit as compared with a conventional current detection device having a single measurement region.

  Moreover, according to this embodiment, since the magnetic detection means 13 is installed in the inner side surrounded by the magnetic shielding member 11, it is resistant to an external magnetic field that causes a disturbance like the conventional one. . For this reason, it can be used with good detection accuracy even in an installation environment where the influence of an external magnetic field due to the presence of an adjacent current path or the like is a concern.

  Furthermore, according to the present embodiment, the first and second sensor parts 13A and 13B constituting the magnetic detection means 13 are three-dimensionally installed so as to be stacked in the vertical direction in the gap G that is the detection part. ing. That is, since the first sensor portion 13A and the second sensor portion 13B constituting the magnetic detection means 13 are individually installed on both the front and back surfaces of the printed circuit board 30, the installation space is small, and the current detection device Significant miniaturization is possible.

  The present invention is not limited to the embodiment described above, and can be implemented in various forms without departing from the gist of the present invention. In other words, in the present embodiment, the present invention is applied for detecting the value of the current flowing through the bus bar 20 installed in an automobile or the like, but it is not limited to this. Wide application in various fields can be expected.

DESCRIPTION OF SYMBOLS 10 Current detection apparatus 11 Magnetic shielding member 12 Internal shielding member 12A, 12B Split member 12C, 12D Both ends of an internal shielding member 13 Magnetic detection means 13A 1st sensor part 13B 2nd sensor part 14 Internal shielding member 20 Conductive member ( Conductive plate; bus bar)
30 Printed circuit board B Magnetic flux density B ₁ Magnetic field strength corresponding to a large current value B ₂ Magnetic field strength corresponding to a small current value G Gap (detection unit)
I current I ₁ large current I ₂ small current R magnetic path S aperture (detection unit)
W Width of magnetic shielding member Φ Magnetic flux (magnetic flux)

Claims (4)

Crossing with respect to the direction in which the current of the current path flows with respect to a current path formed of a magnetic material and having a substantially U-shaped cross section, and three of the four vertical and horizontal surfaces surrounded by the substantially U-shaped section in the cross section. A magnetic shielding member installed in
Inside the substantially U-shaped inside of the magnetic shielding member, the ends of a pair of divided members formed in a substantially L-shaped cross section with a magnetic material are placed close to each other, and arranged as a whole in a substantially U-shaped cross section. An internal shield that is installed transversely with respect to the direction in which the current of the current path flows with respect to the current path in which three of the four vertical and horizontal faces different from the three faces are surrounded by the substantially U-shape. Members,
A plurality of magnetic detection means arranged in the stacking direction of the current path and the inner shielding member in the gap between the end portions of the split member, and having different detectable ranges of the magnitude of magnetic flux density or the strength of magnetic field; ,
A current detection device comprising: The gap is located at the center in the width direction of the current path.
The current detection device according to claim 1. Crossing with respect to the direction in which the current of the current path flows with respect to a current path formed of a magnetic material and having a substantially U-shaped cross section, and three of the four vertical and horizontal surfaces surrounded by the substantially U-shaped section in the cross section. A magnetic shielding member installed in
The three surfaces of the four vertical and horizontal surfaces in the cross-section, which are formed in a substantially U-shaped cross-section with a magnetic material, and an opening is formed in a surface located in the center, inside the substantially U-shaped of the magnetic shielding member. An internal shielding member installed transversely to the direction in which the current of the current path flows with respect to the current path surrounded by the substantially U-shape on another three surfaces different from
A plurality of magnetic detection means arranged in the stacking direction of the current path and the internal shielding member in the opening of the internal shielding member and having different detectable ranges of the magnitude of the magnetic flux density or the strength of the magnetic field;
A current detection device comprising: The opening is located in the center in the width direction of the current path,
The current detection device according to claim 3.

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