JP2003167009A - Current detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a current detector (sensor) suitable for automobile use, on which miniaturization is possible, a process of mounting a current bar can be omitted, manufacturing process is simplified, and cost can be reduced. <P>SOLUTION: A large current pattern 2 capable of applying desired current is formed on a printed circuit board 1 and a hall element 3 is arranged in the vicinity. The printed circuit board 1 having the large current pattern 2 is inserted in a core 4 and contained in a case 6. The printed circuit board 1 is fixed by connecting the large current pattern 2 with connecting terminals 7 with screws 5, where the large current pattern 2 of the printed circuit board 1 is inside the core 4 and the hall element 3 is placed at the gap of the core 4. <P>COPYRIGHT: (C)2003,JPO

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 vehicle mounting.

[0002]

2. Description of the Related Art FIG. 9 is an exploded perspective view showing the structure of a general current detecting device of this type. In the figure, 101 is 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. Reference numeral 105 denotes a gap 106 for inserting the Hall element 104.
It is a tubular core having a core made of ferrite, a silicon steel plate, or the like. Reference numeral 107 denotes a connector-integrated case in which the core 105 is housed, a connector terminal 108 is attached, and a cylindrical body 109 penetrating the inside of the core 105 is provided, and a current bar through which a current flows. 110 is to be inserted.

The current detecting device having the above structure is formed as follows.

(1) A lead-type Hall element 104 is mounted on a printed circuit board 101 having 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 the direction of 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 arranged so that the Hall element 104 enters the direction of the arrow C in the gap 106 of the core 105.
01 is inserted into the case 107, and the connector terminal 108 and the printed board 101 are connected by soldering or the like.

(4) After adjusting the circuit in this state,
The core 105 and the printed circuit board 101 are filled with a molding material.
In addition to the above-mentioned fixing, it is possible to ensure waterproofness without a lid and also to ensure vibration resistance of the core 105 and the printed circuit board 101.

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

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

Next, the principle of this current detection will be described.

Depending on the magnitude of the current flowing in the current bar 110, a magnetic field is generated according to Ampere's right-handed screw law.
This magnetic field is collected by the core 105, and the Hall element 104
To a detectable magnetic flux density. The Hall element 104 inserted in the gap 106 of the core 105 outputs a voltage according to the magnetic flux density generated in the gap portion, and the output voltage of the Hall element 104 is output by the electronic circuit mounted on the printed board 101. Amplify to an appropriate level.
As a result, an output proportional to the magnitude of the current of the current bar 110 can be obtained.

[0012]

The current detecting device as described above has the following problems.

(Structural problems) The external size is restricted by the bus bar (current bar), and it is difficult to reduce the size.

The cross-sectional area of the bus bar is determined by the current capacity, but the cross-sectional area of the bus bar → the hole size of the bus bar → the inner diameter of the core → the outer shape of the core → the outer shape of the sensor are designed, and therefore the cross-sectional area of the bus bar depends. It became a sensor size, and downsizing was difficult. In addition, the size of the core must be designed so that it does not saturate within the range of the current to be detected, and it cannot be reduced unnecessarily, and the wall thickness of the case requires a certain thickness in terms of strength. Is a parameter that is hard to contribute.

It is necessary to fill the resin to fix the core,
Cost and man-hour will be required.

The core is made of ferrite, metal or the like, but in order to fix the core, the inside of the case is fixed by filling with mold resin. This resin filling process is disadvantageous in terms of manufacturing man-hours and cost.

The step of passing the bus bar is complicated.

Also in the assembling step, the bus bar needs to be attached through the predetermined hole, and therefore, there is a problem in that a maker or the like using the device also requires man-hours and increases cost.

Since the Hall element is a lead component, it is difficult to automate an automatic mounter or the like.

Among the electronic components mounted on the PWB (printed circuit board), only the Hall element is a lead component, and all other components are SMDs (surface mount components). Therefore, the SMD can be automated by mounting it on the PWD with an automatic mounter and soldering by reflow, but the Hall element undergoes the labor-intensive process of lead forming → soldering by a robot or manual soldering. However, there was a problem that it would be costly.

Although the Hall element itself has an SMD, in consideration of the direction of the core gap, the resin filling direction, the volume adjustment for adjusting the sensor sensitivity and the offset, etc.,
The element is preferably in a vertical relationship with respect to the PWB, and SMD components cannot be mounted. Finally, the case is filled with resin, but it is necessary to adjust the volume after adjusting the volume of hall elements and circuits. It is limited, and it is difficult to implement miniaturization such as constructing a PWB structurally.

(Problem in Cost) Since all the above structural problems are reflected in the cost, the production of a low cost device is limited in the current structure. Also,
Due to the above structure, miniaturization is reaching its limit,
It is difficult to realize a highly demanded low-cost small-sized device.

The present invention has been made in view of the above-mentioned problems, and it is possible to reduce the size, omit the step of attaching the current bar, simplify the manufacturing process, and reduce the cost. It is an object of the present invention to provide a current detection device that can be realized.

[0024]

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

(1) A current pattern in which a desired current to be detected flows is formed on a printed board, a magnetic sensor is arranged in the vicinity of the current pattern, and the current flowing in the current pattern is detected from the output of the magnetic sensor. I chose

(2) In (1) above, the printed board is a single board in which current patterns and other wiring patterns are mixed.

(3) In the above (1), the printed board is a single board provided with only the current pattern.

(4) In any one of (1) to (3) above, the magnetic sensor is a Hall element surface-mounted on the printed board.

(5) In any one of (1) to (4) above, the current pattern is formed so as to surround the magnetic sensor with the magnetic sensor at the center.

(6) In any one of the above (1) to (5), the printed board is connected to the connection terminal insert-molded in the case in the case.

(7) In any of (1) to (6) above, a magnetism collecting chip is insert-molded on the case and the lid.

(8) In the above (7), the case and the lid are integrally fixed by welding or adhesion.

[0033]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an exploded perspective view showing the configuration of the first embodiment of the present invention, showing an example configured as a non-contact type current sensor.

In FIG. 1, 1 is a PWB (printed board)
Printed circuit board on which circuit wiring pattern is formed as 2
Is a large current pattern through which a desired detected current (here, a large current) flows, and is formed at an appropriate position on the printed circuit board 1. Reference numeral 3 denotes a Hall element as a magnetic sensor arranged in the vicinity of the large current pattern 2, and the current flowing in the large current pattern 2 is detected from the output of the Hall element 3.

Reference numeral 4 is a core arranged around the large current pattern 2, and 5 is a screw for fixedly connecting the large current pattern 2 to the connection terminal 7 of the box-shaped case 6 together with the printed circuit board 1. The connection terminal 7 is the case 6 Is provided so as to penetrate from the inside to the outside. Reference numeral 8 is a connector terminal for electrically connecting the printed circuit board 1 to another device.

FIG. 2 is a sectional view showing the internal structure of the core after assembly. The Hall element 3 is the aforementioned SMD type component, and is surface-mounted on the printed circuit board 1 so as to be positioned in the gap portion of the core 4.

FIG. 3 is a sectional view showing details of the large current pattern 2. The printed board 1 is a single board in which the large current pattern 2 and another normal pattern (wiring pattern) 9 are mixed, or a board having only the large current pattern 2.

As shown in FIG. 4, the printed circuit board 1 is a single substrate provided with only the large current pattern 2, and the other normal patterns 9 are formed on another printed circuit board 10.
It may be configured as a piece substrate.

The large current pattern 2 on the above-mentioned printed board 1 is also called a composite copper thick board or power line.
It is a pattern having a thickness of 00 μm to 400 μm, and substrates having such a pattern can be mass-produced.
Then, as shown in FIGS. 3A and 3B, the layer of the normal pattern (16 μm to 35 μm) 9 and the layer of the large current pattern 2 are mixed on the printed circuit board 1 so that the printed circuit board 1 is directly connected to the printed circuit board 1. A large current can be passed.

For example, if a pattern having a thickness of 400 μm is used, a current capacity of 10 A / mm width is provided, and thus a current of 100 A can be flowed with a width of 10 mm. Also, this is 2
Layered, 200 mm for 10 mm width, 30 for 15 mm width
It will have a capacity of 0A. When the normal pattern and the large current pattern 2 are mixed on one substrate, the large current pattern 2 is sandwiched between the inner layers and the outer layer is the normal pattern. Further, in order to increase the current capacity, the large current pattern 2 can be sandwiched between two layers.

In the case of a two-piece board structure, the board through which the core 4 is passed is the printed board 1 having the large current pattern 2, and the board on which the hall element 3 and the like are mounted is the printed board having the normal pattern. . In this case, as shown in FIG. 3C, the printed board 1 having the large current pattern 2 may be a two-layer board having patterns on both sides. As described above, since the normal substrate and the large current substrate do not need to be electrically connected, a two-piece structure is possible.

Next, a method of assembling the current sensor (current detecting device) having the printed circuit board 1 will be described.

(1) Electronic components such as a surface mount type Hall element 3 and an amplifier circuit are mounted on a printed circuit board 1 provided with a large current pattern 2 by a mounter and a reflow process, and are inserted into a core 4 provided with a gap. To do. At this time, the printed circuit board 1 is designed so that the Hall element 3 is located in the gap portion of the core 4 and the large current pattern 2 passes through the inside diameter of the core.

(2) For the core 4, a desired material such as a magnetic material such as ferrite, a stack of metal plates such as silicon steel plate and permalloy, and the like can be selected depending on the use and price. The gap portion is designed to have a thickness that allows the Hall element 3 and the printed circuit board 1 to be inserted.

(3) The connection terminal 7 is a terminal machined from a metal having good conductivity such as copper, and is used for fixing the sensor and connecting the current line. This connection terminal 7
By insert-molding into the case 6, the case 6 and the connection terminal 7 are integrated. In addition, the connection terminal 7 in the case 6
Has a hole for mounting a printed circuit board, and a screw 5 is screwed into this hole to connect the printed circuit board 1 and the case 6. When the printed circuit board has a two-piece structure, a mounting boss for the ordinary circuit board is separately provided to connect and fix the case 6 and the printed circuit board.

(4) To fix the core 4 and the case 6, a core fixing guide is integrally formed inside the case 6, and the core 4 is fixed to the case 6 by press fitting or the like. Further, in an application where environment resistance such as vibration is required, the core 4 and the printed circuit board 1 may be fixed by resin filling as in the conventional case.

(5) Core 4 and printed circuit board 1 in case 6
After fixing and inserting, the connector terminal 8 and the terminal land of the printed circuit board 1 are soldered, circuit variations and the like are corrected by adjustment such as volume adjustment and laser trimming.

(6) Although not shown, if the application does not require waterproofness, the sensor is completed by attaching a resin-molded lid to the case 6. In applications where waterproofness, environment resistance, etc. are required, by filling the above-mentioned resin, it is possible to ensure predetermined performance.

As described above, in this embodiment, by using the printed circuit board 1 provided with the large current pattern 2, there is no restriction on the outer shape of the sensor by the bus bar as in the conventional case, and the size can be reduced. Also, with the bus bar gone,
The step of attaching the bus bar can be omitted.

Further, in this embodiment, the positional relationship between the core 4 and the printed circuit board 1 is improved, and the SMD type Hall element 3 can be mounted. As a result, the manufacturing process is further simplified and the cost is reduced. Is possible.

FIG. 5 is an exploded perspective view showing the configuration of the second embodiment of the present invention, and the same symbols as those in FIG. 1 indicate the same components.

In FIG. 5, 11 is a lid integrally fixed to the case 6 by welding or adhesion, 12 a is a magnetism collecting chip insert-molded in the lid 11, and 12 b is a magnetism collecting chip insert-molded in the case 6.

In this embodiment, the large current pattern 2 is formed on the printed board 1 so as to surround the hall element 3 with the hall element 3 as the center. The other structure is similar to that of the embodiment shown in FIG.

FIG. 6 is a diagram showing the relationship between the current flowing in the large current pattern 2 of the printed circuit board 1 of this embodiment and the magnetic field.
When the current A flows in the direction of the arrow, the magnetic field B is generated according to the law of the right screw, but the current A flows in a circle, so that the magnetic flux gathers in the center of the circle, that is, in the direction of the Hall element 3.

FIG. 7 is a sectional view showing details of the large current pattern 2. The printed board 1 is a single board in which a large current pattern 2 and other normal patterns (wiring patterns) 9 are mixed.

FIG. 8 is a sectional view showing the internal structure of the case after assembly. In the figure, reference numeral 13 denotes an electronic component mounted on the printed circuit board 1. Further, the magnetic flux collecting chip 12a,
12b is provided on the printed circuit board 1 at a position corresponding to the Hall element 3.

Also in this embodiment, as shown in FIGS. 7A and 7B, the normal pattern (16) is formed on the printed circuit board 1.
By mixing the layer of 9 μm to 35 μm) and the layer of the large current pattern 2, a large current can be passed directly to the printed board 1.

Further, as in the above-mentioned embodiment, for example, 400
If a pattern with a thickness of μm is used, a current capacity of 10 A / mm width is provided, and thus a current of 100 A can be flowed with a 10 mm width. And if this is made into two layers, it will have a capacity of 200 A in 10 mm width and 300 A in 15 mm width. When the normal pattern and the large current pattern 2 are mixed on one substrate, the large current pattern 2 is sandwiched between the inner layers and the outer layer is the normal pattern. Further, in order to increase the current capacity, the large current pattern 2 can be sandwiched between two layers.

Next, a method of assembling the current sensor (current detecting device) of this embodiment having the printed circuit board 1 will be described.

(1) Similar to the embodiment of FIG. 1, electronic components such as a surface mount type Hall element 3 and an amplifier circuit are mounted on a printed circuit board 1 provided with a large current pattern 2 in a mounter and reflow process. At this time, the large current pattern 2 is patterned so as to surround the Hall element 3, and the printed circuit board 1 is designed so that the magnetic flux is most concentrated on the magnetic sensitive portion of the Hall element 3. The Hall element 3 and the other electronic components 13 are connected to each other by a normal pattern patterned on the outer layer, and a processing circuit performs predetermined amplification to obtain an output as a sensor.

(2) In the current method, since the magnetic flux is collected using the closed magnetic circuit core, the generated magnetic flux per unit current is high,
Although it was well within the sensitivity region of the Hall element 3, in the present embodiment, the closed magnetic circuit core is not used, and the magnetic flux collecting effect is enhanced by the current pattern. However, since the magnetic flux collecting effect as much as that of the closed magnetic circuit core cannot be obtained, the magnetic flux collecting chips 12a, 1
By sandwiching the Hall element 3 between 2b, it is possible to enhance the magnetism collecting effect.

For the magnetic flux collecting chips 12a and 12b, not only ferrite but also magnetic material such as permalloy / amorphous can be selected from the viewpoint of cost and effect. Further, the magnetism collecting chips 12a and 12b are integrated with the case 6 by providing a cylindrical convex portion on the lid 11 and the case 6 and insert-molding the convex portion into the convex portion, thereby reducing the number of assembling steps. The positional accuracy with respect to the Hall element 3 can be ensured. The magnetic flux collecting chip 12
When the current flowing through the large current pattern 2 is large and the generated magnetic flux enters the sensitivity region of the Hall element 3, a and 12b are
It does not have to be provided.

(3) The connection terminal 7 is a terminal machined from a metal having good conductivity such as copper, and is used for fixing the sensor and connecting the current line. This connection terminal 7
By insert-molding into the case 6, the case 6 and the connection terminal 7 are integrated. In addition, the connection terminal 7 in the case 6
Has a hole for mounting a printed circuit board, and a screw 5 is screwed into this hole to connect the printed circuit board 1 and the case 6.

(4) Core 4 and printed circuit board 1 in case 6
After fixing and inserting, the connector terminal 8 and the terminal land of the printed circuit board 1 are soldered, circuit variations and the like are corrected by adjustment such as volume adjustment and laser trimming.

(5) The lid 11 can be joined to the case 6 by ultrasonic welding or the like for applications requiring waterproofness, and in the general-purpose type, the lid 11 is connected to the case 6 by adhesion or screw fastening. Further, the magnetic flux collecting chip 12a,
When there is no 12b, the lid 11 may be omitted, and the electronic component 13 may be protected by filling the above-mentioned resin.

As described above, also in this embodiment, by using the printed circuit board 1 provided with the large current pattern 2, there is no restriction on the outer shape of the sensor by the bus bar as in the conventional case, and the size can be reduced. Further, since the bus bar is eliminated, the step of attaching the bus bar can be omitted.

Furthermore, the positional relationship between the core 4 and the printed circuit board 1 is improved, and the SMD type Hall element 3 can be mounted. As a result, the manufacturing process is further simplified and the cost can be reduced.

Further, in this embodiment, since the large current pattern 2 is patterned so as to surround the hole block 3,
The core can be omitted. Then, by omitting the core and insert-molding the magnetic flux collecting chips 12a and 12b on the case 6 and the lid 11, the resin filling required for fixing the core can be omitted.

The present invention is suitable as an on-vehicle current sensor, and is relatively large in an environment with a wide operating temperature range, such as motor control for hybrid cars / electric vehicles, idling control for battery monitoring, and motor control for electric power steering. It is suitable for applications that want to measure current (tens of amps to hundreds of amps).

[0071]

As described above, according to the present invention,
It is possible to reduce the size, omit the step of attaching the current bar, simplify the manufacturing process, and reduce the cost.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a configuration of a first embodiment of the present invention.

FIG. 2 is a sectional view showing the internal structure of the core of the first embodiment.

FIG. 3 is a sectional view showing details of a large current pattern according to the first embodiment.

FIG. 4 is a cross-sectional view showing the configuration in the case of a two-piece substrate.

FIG. 5 is an exploded perspective view showing a configuration of a second embodiment of the present invention.

FIG. 6 is an explanatory diagram showing the relationship between current and magnetic field in the second embodiment.

FIG. 7 is a sectional view showing details of a large current pattern according to a second embodiment.

FIG. 8 is a sectional view showing the internal structure of the case of the second embodiment.

FIG. 9 is an exploded perspective view showing a configuration of a conventional example.

[Explanation of symbols]

1 printed circuit board 2 Large current pattern 3 Hall element 4 core 6 cases 7 connection terminals 9 normal patterns 10 printed circuit boards 11 lid 12a Magnetic flux collection chip 12b Magnetic flux collection chip 13 Electronic components

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kenichi Nakano             2-9-13 Nakameguro, Meguro-ku, Tokyo             NLE Electric Co., Ltd. F-term (reference) 2G017 AA01 AC07 AD53                 2G025 AA03 AA05 AB02 AC04

Claims (8)

[Claims] 1. A method of forming a current pattern in which a desired current to be detected flows on a printed board, disposing a magnetic sensor in the vicinity of the current pattern, and detecting the current flowing in the current pattern from the output of the magnetic sensor. Characteristic current detection device. 2. The current detecting device according to claim 1, wherein the printed board is a single board in which a current pattern and other wiring patterns are mixed. 3. The current detecting device according to claim 1, wherein the printed board is a single board provided with only a current pattern. 4. The magnetic sensor is a Hall element surface-mounted on a printed board.
Any of the current detection devices. 5. The current detecting device according to claim 1, wherein the current pattern is formed so as to surround the magnetic sensor centering on the magnetic sensor. 6. The current detecting device according to claim 1, wherein the printed board is connected to the connection terminal insert-molded in the case in the case. 7. The current detecting device according to claim 1, wherein a magnetism collecting chip is insert-molded on the case and the lid. 8. The current detecting device according to claim 7, wherein the case and the lid are integrally fixed by welding or adhesion.