JPH1073619A - Current detector and electric joint box for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a current accurately over a wide range without lowering the detection accuracy even for a high current by disposing a magnetic core while covering one current shunt and detecting a current flowing through a metal plate based on the detection results of a current flowing through one current shunt. SOLUTION: A current detection bus bar 10 is provided with rectangular notches 11 penetrating the thickness of the bus bar 10 at positions separated by distances L1, L2, respectively, from the opposite sides H1, H2 extending in parallel with the direction of current flow. Current paths 12, 13 are formed on the opposite sides of the notch 11 in the bus bar 10 and a relationship I=I1 +I2 is satisfied between the current I1 flowing through the current path 12 and the current I2 flowing through the current path 13. When a current flows through the current path 12, output voltage of a Hall element 15 is detected by an electric circuit formed on a printed wiring board 16 and the current value I1 is determined. Furthermore, the electric circuit calculates the value of current I flowing through bus bar 10 according to a formula; I=(1+L2/Ll)×I 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a current detector and an electric junction box for a vehicle, and can be applied to, for example, a case where a load current value flowing through a power supply line of a vehicle is detected.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 15, an electric junction box (so-called junction box) 1 is provided with a current detecting device for detecting a load current output from the electric junction box 1 to each load. ing. Here electrical junction box 1
Inputs a power supply current from a battery or an alternator via a bus bar 2A, and inputs the power supply current via a main fuse unit 3 and fuse units 4A and 4B, as well as the bus bars 2B and 2C.
The output is distributed to each load connected to the electric connection box 1 via 2D.

A U-shaped magnetic core 5 is provided in the electric connection box 1 so as to cover the bus bar 2B. A magnetic gap 6 (FIG. 16) of the magnetic core 5 has a magnetic sensing element. Is arranged. FIG. 16 shows the state of the bus bar 2B, the magnetic core 5, and the Hall element 7. The Hall element 7 is connected to a printed wiring board (not shown) of a load detection unit provided in the electric connection box 1.

When a current flows through the bus bar 2 B, a magnetic field is generated in the magnetic core 5, and a voltage corresponding to the magnetic field is obtained from the Hall element 7. This voltage is measured by an electric circuit formed on the printed wiring board, and thus the current value flowing through the bus bar 2B, that is, the load current value can be detected.

[0005]

By the way, as shown in FIG. 17, the relationship between the current value flowing through the bus bar and the voltage value output from the Hall element is defined as a linear region where an output voltage proportional to the current value is obtained. It is divided into a non-linear region 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 not accurate in the nonlinear region.

As is apparent from the figure, if the current flowing through the bus bar becomes large, accurate current detection cannot be performed. As a result, in this type of current detection device, the possible range of current detection 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 view of the above points, and it is an object of the present invention to propose a current detection device capable of performing high-precision current detection in a wide current region without deteriorating the detection accuracy even with a large current. Things.

[0008]

According to a first aspect of the present invention, there is provided a current detecting device having a U-shaped magnetic core disposed so as to cover a metal plate.
The magnetic field generated from the magnetic core according to the current flowing through the metal plate is converted into a voltage by a magnetic sensing element arranged in the magnetic gap portion of the magnetic core, and a current value flowing through the metal plate is detected based on the converted voltage. In the current detecting device, at least two current branch channels that shunt the current flowing through the metal plate are formed in the metal plate, and the magnetic core is disposed so as to cover one of the current branch channels. The current flowing through the metal plate is detected based on the detection result of the current flowing through the one current branch channel.

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

According to a second aspect of the present invention, a notch is formed at a predetermined distance from each side of the metal plate parallel to the direction in which the current flows. By doing so, two current distribution channels are formed on the metal plate.

In the above configuration, a first current branch is formed between the notch and one side of the metal plate, and a second current branch is formed between the notch and the other side of the metal plate. As a result, two branch channels can be easily formed. The total current flowing through the metal plate is
It can be easily obtained from the ratio of the width of the first current branch to the width of the second current branch.

According to a third aspect of the present invention, a magnetic core is disposed so as to cover a narrower one of the two current distribution channels. .

In the above configuration, a smaller current flows through the narrower current branch than the wide current branch, and the current to be detected by the magnetic core and the magnetic sensing element can be further reduced. As a result, the detection accuracy by the magnetic core and the magnetic sensing element is further improved, and thus the current flowing through the metal plate can be detected with higher precision.

According to a fourth aspect of the present invention, there is provided a current detecting device, comprising: bending a metal plate at a substantially right angle along a bending line that is substantially parallel to a current flowing direction and that passes through a notch; The core was arranged so as to cover the current branch at the portion bent at the right angle.

In the above arrangement, when disposing the magnetic core so as to cover the current branch of the portion bent at a right angle, the metal plate is first aligned while aligning the magnetic gap portion and the notch portion of the magnetic core. Move in the direction of the magnetic core. Next, when the magnetic sensing element is arranged at the position of the magnetic gap, the magnetic sensing element is moved in the same direction as the moving direction of the metal plate. As a result, in addition to the effect of claim 2, since each member can be arranged at a predetermined position only by moving it in one direction, assembly becomes easy.

According to a fifth aspect of the present invention, there is provided a current detecting device according to the fifth aspect, wherein the metal plate protrudes laterally from one of the two sides parallel to the direction in which current flows. And a notch formed at a predetermined distance from the periphery of the protrusion to form a current distribution channel, and the protrusion is substantially parallel to both sides of the metal plate and cut out. The magnetic core was bent at a substantially right angle along a bending line passing through the portion, and the magnetic core was arranged so as to cover the current distribution channel formed at the portion bent at the right angle.

In the above arrangement, when disposing the magnetic core so as to cover the current branch formed in the portion bent at a right angle, the magnetic core is moved from the direction in which the current flows through the metal plate. The magnetic core can be arranged, or can be arranged by moving the magnetic core from a direction perpendicular to the direction in which the current flows through the metal plate.
As a result, in addition to the effect of the second aspect, it is possible to obtain an effect that the flexibility at the time of assembly can be increased and the degree of freedom of the layout increases.

According to a sixth aspect of the present invention, there is provided an electric connection box for a vehicle, wherein the current detecting device according to any one of the first to fifth aspects is used.

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

[0020]

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 a current detection device of the present invention, and is used, for example, instead of the bus bar 2B in the electric connection box 1 of the vehicle shown in FIG. A rectangular notch 11 penetrating the thickness of the current detection bus bar 10 is provided in the current detection bus bar 10 at a position separated by distances L1 and L2 from both sides H1 and H2 parallel to the direction in which current flows. Is 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, assuming that the current flowing through the current path 12 is I ₁ and the current flowing through the current path 13 is I ₂ , the currents I, I ₁ , I 2
The relationship of ₂ is I = I ₁ + I ₂ .

Since the widths of the current paths 12 and 13 are selected to be L1 and L2, respectively, the currents I ₁ and 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 bus bar 1
The current value I flowing through 0 can be obtained by calculation.

Therefore, as shown in FIG. 2, a U-shaped magnetic core 14 is arranged so as to cover the current path 12, and a Hall element 15 is arranged in a magnetic gap portion 14A of the magnetic core 14. Further, as shown in FIG. 3, the Hall element 15 and the printed wiring board 16 are electrically connected by the conductive member 17.

As a result, when a current flows through 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, the voltage value is detected by an electric circuit formed on the printed wiring board 16 to obtain a current value I ₁ ,
Further, a current value I flowing through the bus bar 10 is obtained by performing an operation of I = (1 + L2 / L1) × I ₁ by an electric circuit.

In the above embodiment, in this embodiment,
The current value I flowing through the bus bar 10 is determined by detecting the current value I ₁ flowing through the current path 12.
Here, since the current value I ₁ is naturally smaller than the current value I, for example, the bus bar 10 may exceed the detection capability of the magnetic material core 14 and the Hall element 15 (that is, the output voltage of the Hall element 15 becomes smaller than the current value). Even when the current value I flows (which becomes non-linear with respect to the current value), the current value I ₁ does not become so large, and 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 accuracy, and thus can obtain the detected current value I with high accuracy in the electric circuit of the printed wiring board 16. Further, in this embodiment, the narrower current path 12 of the two current paths 12 and 13 is set as the current value detection target, that is, the smaller current value is set as the detection target. Accuracy can be increased.

According to the above configuration, the current I flowing through the bus bar 10 is divided by the current I flowing through the bus bar 10, and one of the current values is set as a detection target by the magnetic core 14 and the Hall element 15. It can be detected with high accuracy.

The current path 12 covered by the magnetic core 14 is different from the case where the entire bus bar 10 is covered by the magnetic core 14.
Since the shape of the magnetic core 12 becomes small, it is possible to use a magnetic core having a small shape. As a result, the configuration can be reduced in size and cost. Therefore, if this is used for an electric junction box of a vehicle, the electric junction box can be downsized. Similarly, since a Hall element 15 for a small current can be used, an inexpensive one can be used.

(2) Second Embodiment FIGS. 4 and 5 showing parts corresponding to those in FIG.
In this embodiment, the bus bar 20 of this embodiment is bent substantially at right angles along a bending line B (indicated by a two-dot chain line in the figure) that is substantially parallel to the direction in which the current I flows and that passes through the notch 11.

FIG. 6 shows a state in which the magnetic core 14 is attached to the bus bar 20. This attachment is performed by first lowering the bus bar 20 in the direction of the arrow while aligning the magnetic gap portion 14A of the magnetic core 14 with the notch portion 11. Next, the Hall element 15 connected to the printed wiring board 16 by the conductive member 17 is lowered in the direction of the arrow to dispose it at the position of the magnetic gap portion 14A.

As described above, in this embodiment, since each member can be arranged at a predetermined position only by moving the member in one direction, assembly becomes easy.

Thus, according to the above configuration, the bus bar 20 is substantially parallel to the direction in which the current I flows, and
Since it is bent substantially at a right angle along the bending line B passing through 1, the current detecting device which can be easily assembled can be realized in addition to the effect of the first embodiment.

Further, as shown in FIG. 7, the magnetic core 14 can be joined to the wiring board 21 provided with the bus bar 20, so that the magnetic core 14 can be easily fixed.

(3) Third Embodiment FIG. 8 shows a bus bar 30 according to a third embodiment.
A protruding portion 31 is formed to extend laterally from one of the two sides H1 and H2 parallel to the direction in which the air flows. A notch 32 penetrating the thickness of the bus bar 30 is formed at a position separated from the periphery of the protruding portion 31 by a predetermined distance L1. This allows the busbar 30
, Two current paths 33 and 34 are formed.

[0035] 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, a relationship of I ₁ : I ₂ = 1 / Ra: 1 / Rb holds 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 equal to the widths L1 and L of the current paths 33 and 34, respectively.
It is determined as a certain constant from 2. That is, 1 / Ra: 1
/ Rb = constant value. Therefore, the current value I ₁ or I ₂
Is known, the current value I flowing through the bus bar 30 can be obtained by calculation.

Here, the bus bar 30 of this embodiment is further changed from the state of FIG. 8 as shown in FIG.
Along the bending line B (FIG. 8) which is substantially parallel to both side edges H1 and H2 and passes through the cutout 32.
1 is formed by bending. Then, as shown in FIG. 10, the magnetic core 15 is arranged so as to cover the current distribution channel 33 formed in the portion bent at a right angle, and the magnetic gap portion 14A is located at the position of the notch 32. At this time, the Hall element 15 may be arranged at the position of the notch 32 in advance.

FIG. 11 shows a bus bar 30 as shown in FIG.
It shows the arrangement of the bus bar 30 when the magnetic core 14 and the Hall element 15 are arranged, the wiring board 31 on which the bus bar 30 is provided, and the printed wiring board 16. And it can be arranged adjacent to the wiring board 31. This allows the space to be used effectively.

9 to 11, the magnetic core 14
When the magnetic core 14 is moved from a direction parallel to the bus bar 30 when the magnetic core 14 is disposed so as to cover the current distribution channel 33 formed in the portion 31 of the bus bar 30 bent at a right angle. However, if the bus bar 30 of this embodiment is used, the assembly can be performed by moving the magnetic core 14 from a direction perpendicular to the bus bar 30 as shown in FIGS.

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 first and second embodiments described above, and in addition to the fact that the In this case, the flexibility can be increased, and the degree of freedom in layout can be increased.

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

[0041]

As described above, according to the first aspect of the present invention, even if the value of the current flowing through the metal plate is large, a highly accurate detection result can be obtained by the magnetic core and the magneto-sensitive element. Thus, it is possible to realize a current detecting device capable of detecting a wide range of current flowing through the metal plate with high accuracy.

According to the second aspect of the present invention, in addition to the effect of the first aspect, it is possible to easily form two branch channels and easily obtain the final current value. A current detection device that can be realized.

According to the third aspect of the invention, in addition to the effect of the first aspect, the detection accuracy by the magnetic core and the magnetic sensing element can be further improved, and thus the current flowing through the metal plate can be further increased. A current detection device capable of detecting with high accuracy can be realized.

According to the fourth aspect of the present invention, in addition to the effect of the second aspect, a current detecting device which can be easily assembled can be realized.

According to the fifth aspect of the present invention, in addition to the effect of the second aspect, a current detecting device capable of increasing flexibility in assembling and increasing the degree of freedom in layout is realized. it can.

Further, according to 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 internal layout is free. It is possible to realize a vehicle electrical junction box with an increased degree.

[Brief description of the drawings]

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

FIG. 2 is a perspective view illustrating 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 illustrating 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 sectional view of a bus bar according to a second embodiment.

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

FIG. 7 is a cross-sectional view illustrating 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 plan view for explaining a bus bar according to a third embodiment.

FIG. 9 is a perspective view for explaining the assembly of the third embodiment.

FIG. 10 is a perspective view illustrating an arrangement of a bus bar, a magnetic core, and a Hall element according to a third embodiment.

FIG. 11 is a cross-sectional view illustrating an arrangement of a bus bar, a magnetic core, a Hall element, a printed wiring board, and a wiring board according to a third embodiment.

FIG. 12 is a perspective view for explaining the assembly of the third embodiment.

FIG. 13 is a perspective view showing an arrangement of a bus bar, a magnetic core, and a Hall element according to the third embodiment.

FIG. 14 is a cross-sectional view illustrating an arrangement of a bus bar, a magnetic core, a Hall element, a printed wiring board, and a wiring board according to the third embodiment.

FIG. 15 is a perspective view showing a configuration of a conventional electromagnetic connection box for a vehicle, partially cut away.

FIG. 16 is a sectional view showing an arrangement of a bus bar, a magnetic core, and a Hall element.

FIG. 17 is a characteristic curve diagram showing current detection characteristics of a magnetic core and a Hall element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Metal plate (bus bar) 11 Notch part 12, 13 Current distribution channel (current passage part) 14 Magnetic core 14A Magnetic gap part 15 Magnetic sensing element (Hall element)

Claims (6)

[Claims] A U-shaped magnetic core is arranged so as to cover a metal plate, and a magnetic field generated from the magnetic core according to a current flowing through the metal plate is arranged in a magnetic gap portion of the magnetic core. In the current detecting device that converts the voltage by the magneto-sensitive element and detects the value of the current flowing through the metal plate based on the converted voltage, at least two current branch channels that shunt the current flowing through the metal plate are provided. A current flowing through the metal plate based on a detection result of a current flowing through the one current branch; the magnetic core being disposed on a metal plate and covering one current branch of the current branch; A current detection device characterized in that a current is detected. 2. The two current distribution channels are formed on the metal plate by forming notches at predetermined distances from both sides of the metal plate parallel to a direction in which current flows. The current detection device according to claim 1, wherein the current detection device is formed. 3. The current detection device according to claim 2, wherein the magnetic core is arranged so as to cover a narrower one of the two current distribution channels. 4. The metal plate is bent at a substantially right angle along a bending line that is substantially parallel to a direction in which the current flows and that passes through the notch, and the current of the magnetic material core is bent at the right angle. The current detection device according to claim 2, wherein the current detection device is arranged so as to cover the shunt channel. 5. A protruding portion is formed on the metal plate so as to extend laterally from one side surface of both sides parallel to a direction in which a current flows, and a predetermined distance from a peripheral edge of the protruding portion. The notch is formed only at a position apart from the metal plate, thereby forming the current shunt channel, and forming the protrusion substantially perpendicular to a bending line that is substantially parallel to both sides of the metal plate and passes through the notch. The current detection device according to claim 1, wherein the magnetic core is disposed so as to cover a current distribution channel formed in the portion bent at a right angle. 6. An electric junction box for a vehicle using the current detecting device according to claim 1.