JP3463879B2 - Current detection device and electric connection box for vehicle - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a current detection device and an electric junction box for a vehicle, and can be applied to, for example, detecting a load current value flowing through a power line of a vehicle.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 11, an electric connection box (so-called junction box) 1 is provided with a current detection device for detecting a load current output from the electric connection box 1 to each load. ing. Electrical junction box 1
Inputs the power supply current from the battery or the alternator via the bus bar 2A, and inputs this through the main fuse part 3 and the fuse parts 4A, 4B, and the bus bars 2B, 2C,
The output is distributed to each load connected to the electric junction box 1 via 2D.

A U-shaped magnetic core 5 is provided in the electric junction box 1 so as to cover the bus bar 2B, and the magnetic gap portion 6 (FIG. 12) of the magnetic core 5 is sensitive. A Hall element 7 as a magnetic element is arranged. The states of the bus bar 2B, the magnetic core 5, and the Hall element 7 are shown in FIG.
2 shows. The hall element 7 is a printed wiring board (not shown) of the load detection unit provided in the electrical junction box 1.
It is connected to the.

Here, when a current flows through the bus bar 2B, a magnetic field is generated in the magnetic core 5, and the Hall element 7 obtains a voltage corresponding to the magnetic field. Then, this voltage is measured by the electric circuit formed on the printed wiring board, and thus the value of the current flowing in the bus bar 2B, that is, the load current value can be detected.

[0005]

By the way, as shown in FIG. 13, the relationship between the current value flowing through the bus bar and the voltage value output from the Hall element is as follows: the linear region where the output voltage is proportional to the current value and the current value. It is divided into non-linear regions where an output voltage proportional to the value cannot be obtained. This is based on the characteristics of the magnetic core, and accurate current detection can be performed in the linear region, but accurate current detection cannot be performed in the nonlinear region.

As is clear from the figure, if the value of the current flowing through the bus bar becomes large, the current value cannot be accurately detected. As a result, in this type of current detection device, the current detection possible range is limited to a region where the current value is relatively small,
There is a problem that the detection accuracy deteriorates when the current value increases.

The present invention has been made in consideration of the above points. It is possible to detect a current with high accuracy in a wide current region without deteriorating the detection accuracy even with a large current, and moreover, a current that is easy to assemble. An attempt is made to propose a detection device and an electric junction box for a vehicle using such a current detection device.

[0008]

In order to solve such a problem, a current detecting device according to a first aspect of the present invention is characterized in that a U-shaped magnetic core is arranged so as to cover a metal plate. A current that converts the magnetic field generated from the magnetic core according to the current flowing through the plate into a voltage by the magnetic sensitive element arranged in the magnetic gap of the magnetic core, and detects the current value flowing through the metal plate based on the converted voltage. In the detection device, two current distribution channels are formed on the metal plate by forming notches at positions separated by a predetermined distance from both sides of the metal plate parallel to the direction of current flow. The magnetic sensing element is disposed in the cutout portion, the magnetic core is disposed so as to cover one of the two current distribution channels, and the magnetic core is the metal plate. Arranged from one side And to assemble the magnetic core and the metal plate are relatively moved so as to be.

In the above structure, the current to be detected by the magnetic core and the magnetic sensing element is not the total current flowing through the metal plate, but the current having a smaller current value than the total current shunted by the shunt flow path. The total current value is obtained based on the detection result of the shunt current, for example, by an electric circuit having an arithmetic function. As a result, even if the current value flowing through the metal plate is large, a highly accurate detection result can be obtained by the magnetic core and the magnetic sensing element, so that the current flowing through the metal plate can be detected with high accuracy.

A first current distribution channel is formed between the notch and one side of the metal plate, and a second current distribution channel is formed between the notch and the other side of the metal plate. As a result, the two branch channels can be easily formed. The total current value flowing through the metal plate can be easily obtained from the ratio of the width of the first current distribution channel and the width of the second current distribution channel.

Moreover, since a smaller current flows in the narrower current distribution channel than in the wider current distribution channel, it is necessary to arrange the magnetic core so as to cover the narrower current distribution channel. The current to be detected by the magnetic core and the magnetic sensing element can be further reduced. As a result, the detection accuracy of the magnetic core and the magnetic sensitive element is further improved, and thus the current flowing through the metal plate can be detected with higher accuracy.

[0012]

[0013]

Further, the vehicle electrical connection box according to claim 2 of the present invention was to use a current detecting apparatus according to claim 1.

As a result, the load current distributed to each load in the vehicle electrical junction box can be detected with high accuracy even if the current value is large, and the assembly of the vehicle electrical junction box can be further improved. Workability can be improved,
Furthermore, the degree of freedom of the internal layout can be increased.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. (1) First Embodiment FIG. 1 shows a current detection bus bar used in the current detection device of the present invention, which is used, for example, in place of the bus bar 2B in the electric junction box 1 of the vehicle shown in FIG. The current detection busbar 10 has rectangular notches 11 penetrating the thickness of the current detection busbar 10 at positions separated by distances L1 and L2 from both sides H1 and H2 parallel to the direction of current flow. Has been formed.

As a result, two current paths 12 and 13 are formed on both sides of the notch 11 in the bus bar 10, and the current I flowing through the bus bar 10 is divided into the current paths 12 and 13. At this time, if the current value flowing in the current path 12 is I ₁ and the current value flowing in the current path 13 is I ₂ , the currents I, I ₁ , I
The relationship of ₂ is I = I ₁ + I ₂ .

Since the widths of the current path 12 and the current path 13 are selected as L1 and L2, respectively, the currents I ₁ ,
The relationship of I ₂ is I ₁ : I ₂ = L1: L2. As a result, if _{one of} the current values I _{1 and} I ₂ is known, the current value I flowing through the bus bar 10 can be calculated.

Therefore, as shown in FIG. 2, a U-shaped magnetic core 14 is arranged so as to cover the current path 12, and the Hall element 1 is provided in the magnetic gap portion 14A located in the cutout portion 11.
Place 5. In addition, as shown in FIG.
5 and the printed wiring board 16 are electrically connected by the conductive member 17.

As a result, when a current flows in the current path 12, a magnetic field corresponding to the magnetic field is generated from the magnetic core 14, and an output voltage corresponding to the magnetic field is obtained from the Hall element 15. Then, this voltage value is detected by the electric circuit formed on the printed wiring board 16 to obtain the current value I ₁ ,
Further, the electric circuit calculates I = (1 + L2 / L1) × I ₁ to obtain the current value I flowing through the bus bar 10.

In the above configuration, in this embodiment,
The current value I flowing through the bus bar 10 is obtained by detecting the current value I ₁ flowing through the current path 12.
Since the current value I ₁ is naturally smaller than the current value I, the bus bar 10 exceeds the detection capability of the magnetic core 14 and the Hall element 15 (that is, the output voltage of the Hall element 15 changes to the current value). Even if a current value I flows (which becomes non-linear), the current value I ₁ does not become so large, so that the Hall element 15 outputs a voltage proportional to the current value I ₁ .

As a result, the magnetic core 14 and the Hall element 15 can detect the current value I ₁ with high precision, and thus the electric circuit of the printed wiring board 16 can obtain the detected current value I with high precision. . Also, the two current paths 12,
The detection accuracy can be further improved by setting the current path 12 having the narrower width out of 13 as the detection target of the current value, that is, by setting the one having the smaller current value as the detection target.

According to the above configuration, the current I flowing through the bus bar 10 is shunted, and the current value of one of them is detected by the magnetic core 14 and the Hall element 15, so that the current I flowing through the bus bar 10 is increased. It becomes possible to detect with accuracy.

In addition, the entire bus bar 10 is made of a magnetic core 14.
Current path 1 covered by the magnetic core 14 as compared with the case of
Since the shape of No. 2 becomes small, it becomes possible to use a small-sized magnetic core 14, and as a result, the size and cost of the structure can be reduced. Therefore, if this is used for the electric connection box of the vehicle, the electric connection box can be downsized. Similarly, the Hall element 15 can be used for a small current, so that an inexpensive element can be used.

(2) Second Embodiment FIG. 4 shows a bus bar 30 according to a second embodiment, in which the current I
A protruding portion 31 is formed so as to extend laterally from one of the two sides H1 and H2 parallel to the flowing direction. In addition, a predetermined distance L1 from the peripheral edge of the protruding portion 31.
A notch 32 that penetrates the thickness of the bus bar 30 is formed at a position separated by only. This makes bus bar 3
At 0, two current paths 33 and 34 will be formed.

[0026] I ₁ The current flowing through this time, the current path 33, the current flowing through the current path 34 When I _2, relationship between the current I, I _1, I ₂ becomes I = I ₁ + I _2. Further, the relationship of I ₁ : I ₂ = 1 / Ra: 1 / Rb is established between the current values I ₁ and I ₂ and the resistances Ra and Rb of the current paths 33 and 34. The resistances Ra and Rb are the width L of each current path 33 and 34.
It is determined as a constant from 1 and L2. That is, 1 / R
a: 1 / Rb = constant value. Therefore, if _{one of} the current values I _{1 and} I ₂ is known, the current value I flowing through the bus bar 30 can be calculated.

Here, the bus bar 30 of this embodiment is further changed from the state shown in FIG. 4 to the bus bar 30 as shown in FIG.
Of the protrusion 3 at a substantially right angle along the bending line B (FIG. 4) passing through the notch 32 and substantially parallel to both sides H1 and H2 of the protrusion 3.
It is formed by bending 1. Then, as shown in FIG. 6, the magnetic core 14 is arranged so as to cover the current distribution flow path 33 formed in the portion bent at a right angle, and the magnetic gap portion 14A is located at the cutout portion 32. At this time, the Hall element 15 may be arranged at the position of the cutout 32 in advance.

9 and 10 show the bus bar 30 in which the bus bar 30, the magnetic core 14 and the Hall element 15 are arranged as shown in FIG. 6, the wiring board 35 provided with the bus bar 30 and the printed wiring board 16. The printed wiring board 16 can be arranged parallel to the wiring board 35 and adjacent to the wiring board 35. This makes it possible to effectively use the space.

Here, in FIGS. 5 to 9, the magnetic core 14 is used.
When the magnetic core 14 is arranged so as to cover the current distribution channel 33 formed in the portion 31 of the bus bar 30 that is bent at a right angle, the magnetic core 14 is moved from the direction parallel to the bus bar 30. However, if the bus bar 30 of this embodiment is used, as shown in FIGS. 8 to 10, the magnetic core 14 can be moved from a direction perpendicular to the bus bar 30 for assembly.

As described above, when the bus bar 30 of this embodiment is used, the current flowing through the bus bar 30 can be detected with high accuracy as in the above-described first and second embodiments, and the assembly of the assembly is also possible. In this case, it is possible to obtain an effect that flexibility in the case can be increased and a degree of freedom of layout can be increased.

(3) Other Embodiments In the embodiment, the case where the current detection device according to the present invention is applied to the electric junction box for a vehicle has been described.
The present invention is not limited to this, and can be applied to various electronic devices that require current value detection.

[0032]

As described above, according to the invention described in claim 1, even if the current value flowing through the metal plate is large, a highly accurate detection result can be obtained by the magnetic core and the magnetic sensitive element. Thus, it is possible to realize a current detection device that can detect a wide range of current flowing through a metal plate with high accuracy.

A first current distribution channel is formed between the notch and one side of the metal plate, and a second current distribution channel is formed between the notch and the other side of the metal plate. As a result, the two branch channels can be easily formed. The total current value flowing through the metal plate can be easily obtained from the ratio of the width of the first current distribution channel and the width of the second current distribution channel.

Moreover, since a smaller current flows in the narrow current distribution channel than in the wide current distribution channel, it is necessary to arrange the magnetic core so as to cover the narrow current distribution channel. The current to be detected by the magnetic core and the magnetic sensing element can be further reduced. As a result, the detection accuracy of the magnetic core and the magnetic sensitive element is further improved, and thus the current flowing through the metal plate can be detected with higher accuracy.

[0035]

[0036]

According to the second aspect of the present invention, the load current distributed to each load can be detected with high accuracy even if the current value is large, and further, the assembly is easy and the degree of freedom of the internal layout is increased. It is possible to realize an electric junction box for a vehicle.

[Brief description of drawings]

FIG. 1 is a plan view showing a bus bar according to a first embodiment.

FIG. 2 is a perspective view showing an arrangement of a bus bar, a magnetic core and a Hall element according to the first embodiment.

FIG. 3 is a cross-sectional view showing an arrangement of a bus bar, a magnetic core, a Hall element and a printed wiring board according to the first embodiment.

FIG. 4 is a plan view for explaining a bus bar according to a second embodiment.

FIG. 5 is a perspective view provided for explaining assembly of the second embodiment.

FIG. 6 is a perspective view showing an arrangement of a bus bar, a magnetic core and a Hall element according to the second embodiment.

FIG. 7 is a cross-sectional view showing an arrangement of a bus bar, a magnetic core, a Hall element, a printed wiring board, and a wiring board according to the second embodiment.

FIG. 8 is a perspective view for explaining the assembly of the second embodiment.

FIG. 9 is a perspective view showing an arrangement of a bus bar, a magnetic core and a Hall element according to the second embodiment.

FIG. 10 is a cross-sectional view showing an arrangement of a bus bar, a magnetic core, a Hall element, a printed wiring board, and a wiring board according to a second embodiment.

FIG. 11 is a perspective view showing a partially broken structure of a conventional electric junction box for a vehicle.

FIG. 12 is a cross-sectional view showing an arrangement of a bus bar, a magnetic core and a Hall element.

FIG. 13 is a characteristic curve diagram showing current detection characteristics by a magnetic core and a Hall element.

[Explanation of symbols]

10 busbars 11 Notch 12, 13 Current path 14 Magnetic core 14A magnetic gap 15 Magnetic Sensitive Element (Hall Element)

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-7-218551 (JP, A) Actually open 63-122267 (JP, U) Actually open 62-58771 (JP, U) Patent 3301526 (JP, B2) (58) Fields surveyed (Int.Cl. ⁷ , DB name) G01R 15/00-15/24 G01R 19/00-19/32 G01R 31/00

Claims (2)

(57) [Claims] 1. A U-shaped magnetic material core is arranged so as to cover the metal plate, and a magnetic field generated from the magnetic material core according to a current flowing through the metal plate is arranged in a magnetic gap portion of the magnetic material core. In the current detection device for converting the voltage by the magnetic field sensitive element, and detecting the value of the current flowing through the metal plate based on the converted voltage, a predetermined value is obtained from both sides of the metal plate parallel to the current flowing direction. By forming a notch at a position separated by a distance of two, two current distribution channels are formed on the metal plate, the magnetic sensing element is arranged at the notch, and the magnetic core is provided at the two sides. One of the two current distribution channels is arranged to cover the current distribution channel, and the magnetic core is moved relative to the metal plate so that the magnetic core is arranged from one side of the metal plate. And assemble Current detecting device, characterized in that. 2. An electric junction box for a vehicle, which uses the current detection device according to claim 1 .