JP2002257866A - Current detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To cope with a small quantity and many kinds, permit reduction of developing man-hours and production management man-hours, and realize cost reduction in a non-contact current detector. SOLUTION: A bus bar (current bar) 1 flowing a current to be detected is branched, separated into a plurality of branching bars 1a, 1b, and a current sensor 2 is interposed in the prescribed branching bar 1a. The current flowing in the branching bar 1a is detected by the current sensor 2, and the current flowing in the bus bar 1 as a whole is detected from the result.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a current detecting device particularly suitable for a vehicle.

[0002]

2. Description of the Related Art FIG. 3 is an exploded perspective view showing the structure of a general current detecting device of this kind. In the figure, reference numeral 101 denotes a printed circuit board provided with a circuit element 102 and a land hole 103, and a mounting hole for a hall element 104 is also provided. 105 is a gap 106 for inserting the Hall element 104
And is formed of ferrite, a silicon steel plate, or the like. Reference numeral 107 denotes a connector-integrated case in which the core 105 is accommodated, a connector terminal 108 is attached, and a cylinder 109 penetrating the inside of the core 105 is provided. A current bar) 110 is inserted.

[0003] The current detecting device having the above configuration is formed as follows.

(1) A lead type Hall element 104 is mounted on a printed circuit board 101 provided with a circuit for amplifying the output of the Hall element 104 and a land hole 103 for connecting a connector terminal.
Is mounted upright in the direction of arrow A.

(2) A core 105 having a gap 106 is inserted in a direction indicated by an arrow B into a case 107 in which a connector with a built-in terminal is integrally molded (insert molded).

(3) The printed circuit board 1 is positioned such that the Hall element 104 enters the gap 106 of the core 105 in the direction of arrow C.
01 is inserted into the case 107, and the connector terminal 108 and the printed circuit board 101 are connected by soldering or the like.

(4) After adjusting the circuit in this state,
The core material 105 and the printed circuit board 101 are filled with a molding material.
Of the core 105 and the printed circuit board 101 so that the core 105 and the printed circuit board 101 can be protected from vibration.

(5) The bus bar 110 is inserted into the cylindrical body 109 of the case 107, and the circuit is driven by the power supplied from the connector terminal 108.

In the current detecting device formed as described above, when a current flows through the bus bar 110, the Hall element 104
Detects this, amplifies the detection output by the printed circuit board 101, and outputs the result to the outside from the connector terminal 108 in the case. Thus, the value of the current flowing through bus bar 110 can be detected.

Next, the principle of current detection will be described.

A magnetic field is generated according to the ampere right-hand rule according to the magnitude of the current flowing through the bus bar 110.
This magnetic field is collected by the core 105 and the Hall element 104
Make the magnetic flux density detectable. Then, the Hall element 104 inserted into the gap 106 of the core 105 outputs a voltage corresponding to the magnetic flux density generated in the gap, and the output voltage of the Hall element 104 is output by an electronic circuit mounted on the printed circuit board 101. Amplify to an appropriate level.
Thus, an output proportional to the magnitude of the current of the bus bar 110 can be obtained.

[0012]

However, the above-described current detecting device has the following problems.

First, in the case of a vehicle, the type of current detection range is increased because it is used for various purposes in a vehicle, but if the current detection range is different, it is necessary to design for each application. In other words, the size (particularly the cross-sectional area) of the bus bar is the same as the number of applications and ranges, and for example, ± 100 A
The cross-sectional areas of the detection busbar and the ± 500A detection busbar are significantly different. Also, the gain of the amplifier (amplifier) is only in the range type. For example, if the amplifier gain in the ± 100 A range is set to 20 times, the amplifier gain in the ± 500 A range can be reduced to 1/5, so that the gain becomes 4 times. The same output is required for the type).

Further, in the case of an on-vehicle use, since a reduction in size is required, it is necessary to provide an insertion port corresponding to the cross-sectional area of the bus bar. Due to this restriction, it is not possible to design the sensor with a bus bar insertion port having a large size in advance to provide versatility. Therefore, the size of the core is determined from the size of the bus bar insertion opening, and the outer shape of the sensor is determined. Therefore, types of cores and cases are required according to types of current detection ranges.

In recent years, hybrid cars and electric cars have been sold by many manufacturers, but the quantity is not large. Therefore, the current sensors to be mounted are required to be compatible with a small quantity and a large variety of electric current sensors. In addition, even for ordinary gasoline-powered vehicles, the use of current sensors has been widened for the purpose of improving fuel efficiency such as idling stop, so that not only passenger cars but also trucks and buses are covered. Therefore, the current detection range extends to about ± several tens A to ± 1000 A, and the type is increasing.

In recent years, exhaust gas from diesel vehicles such as trucks and buses has become one of the causes of environmental pollution.
Additional functions such as idle stop are provided as improvement means. Therefore, the demand for a current sensor for a large current application (about 500 A to 1000 A) is increasing.

For this reason, it is necessary to design the core, case, circuit gain setting, etc. for each vehicle type and current range, which increases the burden of design man-hours, design period, development costs, etc. The burden on production management, such as increase in the number of setup steps and parts management due to multi-product production, increases.

Further, if there is a sensor designed with the largest bus bar insertion port, it is sufficient to simply switch the gain of the amplifier, but there is a problem of increasing the sensor size and cost (increase in core volume and case size and increase in the amount of filled resin). There is no versatility for in-vehicle use. In particular, in the case of a large current, there is a problem that the cost is extremely high and does not match low cost requirements.

The present invention has been made in view of the above-described problems, and can easily cope with many kinds of small-quantity products, can reduce development man-hours and production management man-hours, and can reduce costs. It is an object to provide a current detection device.

[0020]

The current detecting device according to the present invention is configured as follows.

(1) A non-contact type current detecting device,
A bus bar through which a current to be detected flows is branched, and a current sensor for detecting a current flowing through the branch bar is provided in any of the branched branch bars.

(2) In the above (1), the bus bar has a structure in which a plurality of branch bars are integrated.

(3) In the above (1), the bus bar has a structure in which a plurality of branch bars are separated.

(4) In any of the above (1) to (3), the ratio of the current flowing through each branch bar is set according to the sectional area ratio of each branch bar.

(5) In any one of the above (1) to (4), the connection conditions of the branch bars are made the same, and the contact resistances of the respective branch bars are made uniform.

[0026]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing a main part of a non-contact type current detecting device according to the present invention. In FIG. 1, reference numeral 1 denotes a bus bar (current bar) through which a current to be detected flows, which is branched into a plurality of (here, two) branch bars 1a and 1b according to the use. Then, a current sensor 2 for detecting a current flowing through any one of the predetermined branch bars 1a.
Are interposed (arranged). Reference numeral 3 denotes a mounting base for fixing the branch bars 1a and 1b.

The current sensor 2 has the same configuration as that shown in FIG. 3 and will not be described in detail. However, a core having a through-hole of the branch bar 1a and a magneto-electric converter inserted in a gap of the core are provided. An element (Hall element) is provided, and the current flowing through the branch bar 1a, that is, the current flowing through the bus bar 1, can be detected by amplifying and taking out the output of this element.

FIG. 2 is a cross-sectional view of the current sensor 2, showing various examples of the configuration of the bus bar 1. (A) of the figure is of a horizontal type, and is the same as FIG.
a and 1b are arranged in parallel in the horizontal direction. (B)
Is a vertical type, in which two branch bars 1a and 1b are arranged in parallel in the vertical direction. (C) shows a composite type.

Each of the bus bars 1 is provided with a corresponding one of the branch bars 1.
a, 1b may have an integral structure, and each branch bar 1
a and 1b may have a separated structure. Then, the ratio of the current flowing through each branch bar 1a, 1b is set according to the cross-sectional area ratio of each branch bar 1a, 1b, and the current sensor 2
The cross-sectional area of the branch bar 1a provided with is determined. The connection conditions of the branch bars 1a and 1b are the same, and the contact resistances of the branch bars 1a and 1b are equalized.

In this embodiment, a plurality of current ranges can be covered by one type of current sensor 2 by using the bus bar 1 branched in two directions as described above. Specifically, the current sensor 2 of the bus bar 1 branched in two directions
If the branch bar 1a penetrating through the current sensor 2 is denoted by A and the branch bar 1b not penetrating through the current sensor 2 is denoted by B, the current flowing according to the ratio of each resistance is divided. Table 1 shows examples of the detected current and the branch current of the bus bar 1.

[0032]

[Table 1]

As shown in Table 1, the current can be arbitrarily branched depending on the ratio of the resistance of the portion A to the portion B.

Further, the resistance value of the bus bar 1 is proportional to the cross-sectional area if the same material and the same length are used from the characteristics of general conductors. Thus, the ratio of the resistance component can be arbitrarily changed. Therefore, considering the example of Table 1 in terms of the cross-sectional area, the branch bars 1a,
The current can be branched by changing the cross-sectional area of 1b. Table 2 shows an example of the detected current of the bus bar 1 and the cross-sectional area (relative ratio) of the A and B portions.

[0035]

[Table 2]

As shown in Table 2, assuming that the cross-sectional area of the portion A is 100, the cross-sectional area of the portion B is obtained according to the current to be branched.

If the portions A and B have the same thickness, it is possible to manufacture them in an integrated structure by a method such as wire cutting. However, when the thickness is different or the installation direction in the longitudinal direction is different (FIG. 2). (C)) or in the case of a vertical type (see (b) of FIG. 2), a separation structure is desirable.

In either the integral structure type or the separation structure type, the bus bar mounting portion is connected by a screw or a nut. However, if there is a difference in the contact resistance, there is a possibility that the error of the branched current increases. . Therefore, it is necessary to devise a method in which conditions such as the screw diameter and the tightening torque are adjusted.

It is feared that the flowing current causes the bus bar 1 to generate heat and the relative value of the resistance to change. However, if a current flows as designed to the branched bus bar, a per unit area (cross-sectional area) is required. Since the current value (current density) is the same, the temperature rise value is the same. Therefore, the increase in the resistance due to the heat generated by the bus bar itself changes at the same ratio between the portion A and the portion B, and the ratio of the resistance values does not change due to the temperature change.

As described above, in this embodiment, for example, ± 100
If the sensor A is used, the use of the current sensor having a wider detection range can be handled by changing the shape (cross-sectional area ratio) of the bus bar 1, and the same sensor can be used.

Therefore, the problems of designing with a small number of products (increase in design man-hours and design time and design cost) and the problems of the production department (setup time and parts management, etc.) are caused by the design of the bus bar 1. This can be solved only by the above, and the man-hours for development and production management can be reduced.

Further, a plurality of applications can be covered by one sensor, and a large number of products can be produced, so that the cost can be reduced by the mass production effect.

It should be noted that the present invention has a wide operating temperature range and a relatively large current (number It is most suitable for applications that want to detect tens A to several hundreds A).

[0044]

As described above, according to the present invention,
In a non-contact type current detection device, there is an effect that it is possible to easily cope with many kinds of small quantities, to reduce the number of development steps and production management steps, and to reduce the cost.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a main part of a current detection device according to the present invention.

FIG. 2 is a cross-sectional view of the current sensor according to the embodiment.

FIG. 3 is an exploded perspective view showing a configuration of a general current detection device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bus bar 1a Branch bar 1b Branch bar 2 Current sensor

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kenichi Nakano 2-9-13 Nakameguro, Meguro-ku, Tokyo F-term in Stanley Electric Co., Ltd. (reference) 2G025 AA00 AB02 AB04

Claims (5)

[The claims] 1. A non-contact type current detecting device, wherein a bus bar through which a current to be detected flows is branched, and a current sensor for detecting a current flowing through the branch bar is installed in any of the branched bars. A current detection device, characterized in that: 2. The current detecting device according to claim 1, wherein the bus bar has a plurality of branch bars formed integrally. 3. The current detecting device according to claim 1, wherein the bus bar has a structure in which a plurality of branch bars are separated. 4. The current detecting device according to claim 1, wherein a ratio of a current flowing through each branch bar is set according to a sectional area ratio of each branch bar. 5. A connection bar according to claim 1, wherein the connection conditions of the branch bars are the same, and the contact resistances of the branch bars are uniform.
The current detection device according to any one of the above.