JP7013222B2 - Current sensor - Google Patents

Description

The present invention relates to a current sensor that calculates a current value based on a magnetic field generated by a measured current.

As a current sensor that calculates a current value based on a magnetic field generated by a current, the one described in Patent Document 1 is known. The current sensor described in Patent Document 1 accommodates a conductor through which a measured current flows and a magnetic sensor for measuring an induced magnetic field in which a measured current is generated in a case having a lid, and houses the bottom of the case and the magnetic sensor. It is equipped with a magnetic shield fixed to the lid by integral molding.

In the current sensor of Patent Document 1, the signal of the magnetic sensor can be output to the outside by exposing the connector mounted on the substrate at the opening provided in the side wall of the case and connecting the connector from the outside. It has become. The connector on the substrate side in Patent Document 1 is positioned and fixed by the side wall and the lid of the case.

On the other hand, in the current sensor, it may be necessary to project the connection terminal above the lid due to the positional relationship of the connected devices and the like. In this case, as in Patent Document 1, it becomes difficult to position the connection terminal by the side wall and the lid of the case.

Japanese Unexamined Patent Publication No. 2017-102022 Japanese Unexamined Patent Publication No. 2002-039788

When it is necessary to project the connection terminal above the lid in the current sensor, for example, as in the sensor described in Patent Document 2, a U-shaped or J-shaped connection terminal may be integrally molded in the case. Conceivable.

However, when the connection terminal is integrally molded with the case, the connection terminal protruding from the case is positioned and fixed integrally with the case, and the degree of freedom is reduced. It may be difficult.

On the other hand, if the strength of the case is lowered in order to increase the degree of freedom of the connection terminal with respect to the case, the clearance between the substrate on which the magnetic sensor is mounted and the conductor may fluctuate, and the accuracy of the magnetic sensor may decrease.

In the present invention, in order to solve the above problems, in a current sensor that outputs the sensor output to the outside via the connection terminal, the degree of freedom in positioning the connection terminal is high, and the connection terminal has some positional fluctuation. It is an object of the present invention to provide a current sensor that does not affect the accuracy of the sensor even in such a case.

In order to achieve the above object, the current sensor of the present invention includes a bus bar through which a current flows, a magnetic sensor for detecting an induced magnetic field generated by the current flowing through the bus bar, and an insulating substrate on which the magnetic sensor is mounted. A case that accommodates a part of the bus bar and the substrate and has a bottom portion, a side wall portion, and a lid portion, is connected to the magnetic sensor via the substrate, and outputs a signal from the magnetic sensor to the outside of the case. A current sensor including a possible connection terminal, wherein the connection terminal includes a board connection portion connected to the substrate and an external connection portion protruding outward from the case toward the upper side of the lid portion. The fixing portion is provided between the substrate connection portion and the external connection portion and is fixed to the case. The fixing portion has an insulation holding portion covered with an insulator, and the insulation holding portion is provided. Is fixed to the bottom of the case.

According to the current sensor of the present invention, since the insulation holding portion is fixed to the bottom of the case, the connection terminal has an insulation holding portion protruding from the bottom of the case and an external connecting portion protruding from the insulation holding portion to the outside. The degree of freedom in positioning can be increased. Also, even if the connector of the connected device is connected to the external connection part and the position of the external connection part changes, the insulation holding part is held at the bottom of the case, so the board connection part is not affected. .. Therefore, since the positional relationship between the bus bar and the magnetic sensor does not change, the accuracy of the current sensor can be ensured.

Further, in the current sensor of the present invention, the lid portion is provided with an opening to which a magnetic shield is attached according to the position of the magnetic sensor and the connection terminal is led out to the outside, and the insulation holding portion is the insulation holding portion. It is preferable that the case protrudes to the outside through the opening and a gap is provided between the insulation holding portion and the opening.

According to this configuration, even if the connector of the connected device is connected to the external connection part and the position of the external connection part changes, the insulation holding part is covered because there is a gap between the insulation holding part and the opening. Do not touch the part. As a result, the positional relationship between the magnetic shield provided on the lid and the magnetic sensor does not change, so that the detection accuracy of the current sensor can be maintained.

Further, the current sensor of the present invention further includes a protective cover that protects the external connection portion and is detachably attached to the insulation holding portion, and the insulation holding portion is located above the lid portion. It is preferable to have a stopper that comes into contact with the protective cover.

According to this configuration, when the protective cover for protecting the external connection portion is attached, the protective cover comes into contact with the stopper provided in the insulation holding portion. Since this stopper abuts on the protective cover at a position above the lid portion, the protective cover does not abut on the lid portion. Therefore, even when the protective cover is attached, the positional relationship between the magnetic shield provided on the lid and the magnetic sensor does not change, so that the detection accuracy of the current sensor can be maintained.

Further, in the current sensor of the present invention, it is preferable that the insulation holding portion includes an exposed portion capable of contacting the connection terminal from the outside of the case. According to this configuration, when the probe of the tester or the like is brought into contact with the connection terminal in the inspection of the current sensor or the like, it can be brought into contact with the exposed portion provided in the insulation holding portion. Therefore, it is not necessary to remove the protective cover at the time of inspection, and the inspection can be easily performed.

Further, in the current sensor of the present invention, it is preferable that a plurality of the connection terminals are provided in parallel, and the adjacent exposed portions are arranged in a staggered manner. When an exposed portion is provided in the insulation holding portion of a plurality of connection terminals provided in parallel, if the exposed portion is provided, the distance between the adjacent exposed portions becomes narrow, so that the portion may be cracked or the like. By arranging the exposed portions in a staggered manner, the distance between the exposed portions can be increased, so that the strength of the insulation holding portion can be ensured.

According to the present invention, in a current sensor that outputs the sensor output to the outside via a connection terminal, the degree of freedom in positioning the connection terminal is high, and even if the connection terminal has some positional fluctuations. , It is possible to provide a current sensor that does not affect the accuracy of the sensor.

The perspective view which shows the appearance of the current sensor which is an example of embodiment of this invention. A partially exploded view of the current sensor of FIG. FIG. 1 is a sectional view taken along line III-III of the current sensor of FIG. (A) and (B) are perspective views of the terminal unit used in the current sensor of FIG.

Next, the current sensor, which is an example of the embodiment of the present invention, will be described with reference to FIGS. 1 to 4. The current sensor of this embodiment is a sensor that can be used in a device that requires a large current, such as a control device used in a hybrid vehicle or an electric vehicle.

FIG. 1 is a perspective view showing the appearance of the current sensor of the present embodiment. FIG. 2 is a perspective view showing a state in which the lid portion of the current sensor, the magnetic shield portion of the lid portion, and the substrate are disassembled. FIG. 3 is a sectional view taken along line III-III of FIG. 1 showing a state of a terminal unit, a case, and a substrate. FIG. 4 is a perspective view of the terminal unit used in the current sensor.

As shown in FIG. 1, the current sensor 1 of the present embodiment is provided in parallel in the width direction (X direction in FIG. 1) and extends in the longitudinal direction (Y direction in FIG. 1), and three bus bars 2 thereof. A case 10 for accommodating a part of the bus bar 2 and a terminal unit 20 extending upward (Z direction in FIG. 1) from the case 10 are provided. A transparent protective cover 3 made of synthetic resin is detachably attached to the terminal unit 20.

As shown in FIGS. 1 to 3, the case 10 of the current sensor 1 has a lid portion 11, a side wall portion 12, and a bottom portion 13. The bottom portion 13 and the side wall portion 12 of the case 10 are integrally formed, and an insulating substrate 30 or the like is housed therein.

The lid portion 11 is placed on the upper end edge of the side wall portion 12 of the case 10 and fixed to the side wall portion 12 by a screw 11a. The lid portion 11 is formed with a lid portion opening 11b that leads the terminal unit 20 to the outside of the case 10. Further, the lid portion magnetic shield 11c is integrally molded and attached to the lid portion 11. Note that FIG. 2 shows a state in which the lid portion magnetic shield 11c is separated from the lid portion 11.

The side wall portion 12 is formed so as to surround the periphery of the bottom portion 13 at a predetermined height, and houses the substrate 30 and the like inside. Further, the side wall portion 12 is formed with a side wall opening 12a at a position where the terminal unit 20 is mounted so that a part of the terminal unit 20 is exposed to the outside.

Similar to the lid portion 11, a bottom magnetic shield (not shown) is fixed to the bottom portion 13 by integral molding. Further, a part of the bus bar 2 is integrally molded on the bottom portion 13. As described above, since the bus bar 2 and the bottom magnetic shield are integrally molded on the bottom portion 13, the positional relationship between the two is maintained, so that the accuracy of the current sensor 1 becomes stable.

As shown in FIGS. 2 and 3, the substrate 30 is housed inside the case 10, and the magnetic sensor 31 is mounted on the surface of the substrate 30. The magnetic sensor 31 is a sensor that detects an induced magnetic field generated by a current flowing through the bus bar 2.

The board 30 is provided with the same number of through holes 32 to which the board connecting portion 23 of the terminal unit 20, which will be described later, is connected to the number of connecting terminals 21. As shown in FIG. 3, the board connection portion 23 of the terminal unit 20 is inserted and soldered to the through hole 32.

As shown in FIG. 3, the terminal unit 20 is provided with a connection terminal 21 which is a metal plate-shaped member bent into a substantially J shape and an insulation provided in a portion of the connection terminal 21 housed in a case 10. It is formed from an insulating holding portion 22 made of synthetic resin, which is a body.

The connection terminal 21 is located between the board connection portion 23 connected to the substrate 30, the external connection portion 24 projecting outward toward the top of the lid portion 11, and the board connection portion 23 and the external connection portion 24. It has a fixing portion 25 provided and fixed to the case 10. The connection terminal 21 can output a signal from the magnetic sensor 31 to the outside of the case 10. Further, the fixing portion 25 of the connection terminal 21 is covered with the insulation holding portion 22.

In the current sensor 1 of the present embodiment, the terminal unit 20 is integrally molded with an insulation holding portion 22 around a plurality of connection terminals 21 arranged in parallel in advance by a dedicated injection molding die (not shown). The insulation holding portion 22 includes a buried portion 26 fixed to the bottom portion 13 of the case 10, and an upright portion 27 that stands up from the buried portion 26.

As shown in FIG. 4B, the upright portion 27 of the insulation holding portion 22 is formed with a stopper 28 extending in the width direction at an upper position. The stopper 28 is a portion where the lower end portion of the protective cover 3 abuts, and is formed at a position above the surface of the lid portion 11 as shown in FIG.

As a result, when the protective cover 3 for protecting the external connection portion 24 is attached, the lower end portion of the protective cover 3 comes into contact with the stopper 28 provided on the insulation holding portion 22. Since the stopper 28 is provided at a position above the surface of the lid portion 11, the stopper 28 does not come into contact with the lid portion 11 even when the protective cover 3 is attached.

Further, as shown in FIG. 3, a gap G is formed between the lid opening 11b provided in the lid 11 and the upright portion 27. As a result, even when a force is applied to the external connection portion 24 or the upright portion 27 from the outside, the upright portion 27 does not come into contact with the lid portion 11.

The upright portion 27 of the insulation holding portion 22 is formed with an exposed portion 29 so that the conductive surface of each connection terminal 21 is exposed to the outside. As shown in FIG. 4B, the exposed portions 29 are arranged in a staggered manner with their positions changed in the Z direction from the exposed portions 29 of the adjacent connection terminals 21.

By arranging the exposed portions 29 in a staggered manner in this way, it is possible to take a longer distance between the exposed portions 29 as compared with the case where the exposed portions 29 are arranged in a row with the same height in the Z direction. As a result, the strength of the insulation holding portion 22 can be ensured.

Further, the side edge portion of the embedded portion 26 of the insulation holding portion 22 shown in FIGS. 4 (A) and 4 (B) is a concavo-convex portion 26a for strengthening the bond between the resin and the resin forming the case 10. Is formed.

In the current sensor 1 of the present embodiment, the terminal unit 20 is injection-molded integrally with the bottom portion 13 and the side wall portion 12 of the case 10. A buried portion 26 of the insulating holding portion 22 of the terminal unit 20 is embedded in the bottom 13 of the case 10, and the bottom 13 of the case 10 and the insulating holding portion 22 are embedded by the uneven portion 26a provided in the buried portion 26. The bond with the portion 26 is strong.

Further, as shown in FIG. 3, in the current sensor 1 of the present embodiment, the board connection portion 23 of the connection terminal 21 is inserted into the through hole 32 from the back surface side of the board 30 and soldered. A circuit pattern (not shown) is formed on the surface of the substrate 30 from the through hole 32 to the magnetic sensor 31. Therefore, the connection terminal 21 is electrically connected to the magnetic sensor 31 via the substrate 30.

Further, the fixing portion 25 continuous with the substrate connecting portion 23 is covered with the insulation holding portion 22, and the embedded portion 26 of the insulation holding portion 22 is integrally molded with the bottom portion 13 of the case 10. Further, the terminal unit 20 is formed in a J shape, and the board connection portion 23 of the connection terminal 21 is connected to the through hole 32 from the back surface side of the board 30.

With this configuration, when the current sensor 1 is connected to another unit, even if an external force is applied to the external connection portion 24 or the upright portion 27 of the insulation holding portion 22, the embedded portion of the insulation holding portion 22 Since the 26 and the bottom 13 of the case 10 are firmly held, the board connecting portion 23 beyond the buried portion 26 is not affected by the outside. Therefore, since the positional relationship between the magnetic sensor 31 mounted on the substrate 30 and the bus bar 2 does not change, the accuracy of the current sensor 1 can be ensured.

Further, in the current sensor 1 of the present embodiment, the upright portion 27 of the insulation holding portion 22 is exposed to the outside by the side wall opening 12a, and the metal portion of the connection terminal 21 is exposed by the exposed portion 29 provided in the upright portion 27. It is exposed to the outside. Therefore, when inspecting the current sensor 1 of the present embodiment, the probe (not shown) of the inspection device can come into contact with the connection terminal 21 via the exposed portion 29. Therefore, since it is not necessary to remove the protective cover 3 to expose the external connection portion 24 at the time of inspection, the inspection work can be facilitated and unnecessary interference with the connection terminal 21 can be prevented. ..

Further, in the present embodiment, since the protective cover 3 is made of a transparent resin, the shape of the external connection portion 24 can be visually recognized from the outside. Therefore, even when the current sensor 1 is attached to another unit, it is possible to confirm whether or not the connection is possible without removing the protective cover 3.

When the current sensor 1 of the present embodiment is used, for example, in a control device of a hybrid vehicle, a connector (not shown) of another unit of the control device is connected to the external connection portion 24 of the terminal unit 20. When another unit is connected to the current sensor 1 of the present embodiment, an external force may be applied to the external connection portion 24 and the insulation holding portion 22 of the terminal unit 20, causing a change in position.

In this case, the lid portion 11 is formed with a lid opening 11b, and a gap G is formed between the upright portion 27 of the insulation holding portion 22 and the edge portion of the lid opening 11b, so that the terminal unit 20 is formed. Even if the positions of the external connection portion 24 and the insulation holding portion 22 are changed, the influence of the change does not reach the lid portion 11. Therefore, since the positional relationship between the magnetic shield 11c of the lid provided on the lid 11 and the magnetic sensor 31 is not affected, the accuracy of the current sensor 1 can be ensured.

In the above embodiment, the embedded portion 26 of the insulation holding portion 22 is embedded in the bottom portion 13 of the case 10, but the present invention is not limited to this, and a part of the upright portion 27 is embedded in the side wall portion 12 of the case 10. It may be fixed. Further, although the external connection portion 24 of the terminal unit 20 is projected outward from the lid portion opening 11b of the lid portion 11, it may be projected outward from the side wall portion 12 without providing an opening in the lid portion 11. ..

Further, in the above embodiment, the exposed portion 29 of the insulation holding portion 22 is exposed by providing the rectangular side wall opening 12a in the side wall portion 12 of the case 10, but the present invention is not limited to this, and the side wall portion 12 is external. A hole may be provided so that a probe or the like can be inserted from the space.

1 ... current sensor 2 ... bus bar 3 ... protective cover 10 ... case 11 ... lid 11b ... lid opening 11c ... lid magnetic shield 12 ... side wall 13 ... bottom 20 ... terminal unit 21 ... connection terminal 22 ... insulation holding part 23 ... Board connection part 24 ... External connection part 25 ... Fixed part 26 ... Embedded part 26a ... Concavo-convex part 27 ... Standing part 28 ... Stopper 29 ... Exposed part 30 ... Board 31 ... Magnetic sensor

Claims (5)

The bus bar through which the electric current flows,
A magnetic sensor that detects the induced magnetic field generated by the current flowing through the bus bar, and
An insulating board on which the magnetic sensor is mounted and
It has a bottom portion, a side wall portion formed so as to surround the bottom portion, and a lid portion arranged so as to cover a space formed by the bottom portion and the side wall portion, and a part of the bus bar is provided in the space. A case that can accommodate the substrate and
A current sensor connected to the magnetic sensor via the substrate and provided with a connection terminal capable of outputting a signal from the magnetic sensor to the outside of the case.
The connection terminal is located between a board connection portion connected to the substrate, an external connection portion protruding outward from the case toward the upper side of the lid portion, and the board connection portion and the external connection portion. It has a fixing part that is positioned and fixed to the case.
The current sensor, characterized in that the fixed portion has an insulating holding portion coated with an insulator and is fixed only to the bottom portion of the case in the insulating holding portion. The lid portion is provided with an opening to which a magnetic shield is attached according to the position of the magnetic sensor and the connection terminal is led out to the outside.
The insulation holding portion protrudes to the outside of the case through the opening.
The current sensor according to claim 1, wherein a gap is provided between the insulation holding portion and the opening. Further provided with a protective cover that protects the external connection portion and is detachably attached to the insulation holding portion.
The current sensor according to claim 2, wherein the insulation holding portion includes a stopper that abuts on the protective cover at a position above the lid portion. The current sensor according to any one of claims 1 to 3, wherein the insulation holding portion includes an exposed portion capable of contacting the connection terminal from the outside of the case. The current sensor according to claim 4, wherein a plurality of the connection terminals are provided in parallel, and the adjacent exposed portions are arranged in a staggered pattern.

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