JP2014077682A - Current sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a current sensor which can flexibly cope with change of the number or the like of detection object currents.SOLUTION: As shown in Figs. 1(a) and (b), a current sensor 1 includes a plurality of current sensor units 2 each of which is provided integrally with a bus bar 3 for generating a magnetic field at the periphery thereof by flowing a detection object current; a core 4 which has a ring shape with a gap 40 at a part thereof, and in which the bus bar 3 is inserted into the center of the ring; and a magnetism detection sensor 5 which is arranged at the gap 40, and detects a change of the magnetic field in the gap 40, and the current sensor 1 is configured by further integrating the plurality of current sensors units 2.

Description

  The present invention relates to a current sensor.

  As a conventional technique, a bus bar through which a current to be measured flows, a sub bus bar having both ends fixed on the bus bar and having an intermediate part extending away from the bus bar, and a sub bus bar surrounded by the intermediate part, are caused by the current flowing through the sub bus bar. A current sensor is known that includes a magnetic core in which a magnetic sensor for measuring a magnetic field is incorporated (see, for example, Patent Document 1).

  A plurality of the current sensors can be arranged side by side in parallel with the sub-bus bars in a posture facing the same side. The plurality of current sensors are configured compactly because the magnetic cores surrounding the sub-bus bars are supported by a common substrate.

JP 2007-212306 A

  However, in the case of manufacturing current sensors having different numbers of currents to be detected, the conventional current sensor needs to consider the structure of the entire current sensor, and there is a problem that the manufacturing cost and the time required for manufacturing increase. Further, in the conventional current sensor, it is necessary to position the magnetic core or the like according to the number of currents to be detected, and it becomes difficult to reach the target accuracy.

  Accordingly, an object of the present invention is to provide a current sensor that can flexibly cope with changes in the number of currents to be detected.

  One embodiment of the present invention includes a bus bar that generates a magnetic field around a current to be detected flowing, a ring shape in which a gap is formed in part, a core in which the bus bar is inserted in the center of the ring, and a gap And a plurality of current sensor units integrated with a magnetic sensor for detecting a change in the magnetic field in the gap. The plurality of current sensor units provide a further integrated current sensor.

  According to the present invention, it is possible to flexibly cope with changes in the number of currents to be detected.

FIG. 1A is a perspective view of a current sensor according to the first embodiment, and FIG. 1B is a perspective view of a current sensor unit. FIG. 2 is a schematic diagram of the core according to the first embodiment. FIG. 3A is an exploded perspective view of the current sensor according to the second embodiment, and FIG. 3B is a top view of the current sensor. FIG. 4A is an exploded perspective view of the current sensor according to the third embodiment as viewed from the side, and FIG. 4B is a cross-sectional view of the main part for explaining the mounting portion of the current sensor.

(Summary of embodiment)
The current sensor according to the embodiment has a bus bar that generates a magnetic field around the current to be detected flowing, a ring shape in which a gap is formed in part, and a core in which the bus bar is inserted in the center of the ring, And a plurality of current sensor units that are integrated with a magnetic sensor that is arranged in the gap and detects a change in the magnetic field in the gap, and the plurality of current sensor units are further integrated to form a schematic configuration.

  This current sensor can achieve the target positioning accuracy in units of current sensor units, and further integrates the current sensor unit according to the number of currents to be detected, so the number of currents to be detected, etc. It can respond flexibly to changes.

[First embodiment]
(Configuration of current sensor 1)
FIG. 1A is a perspective view of a current sensor according to the first embodiment, and FIG. 1B is a perspective view of a current sensor unit. In each drawing according to the embodiment, the ratio of the drawn image to the image may be different from the actual ratio.

As an example, the current sensor 1 is a sensor mounted on a vehicle. As an example, the current sensor 1 is mainly used for the purpose of measuring a current flowing through a three-phase motor. This three-phase motor is used, for example, as a drive source for a hybrid vehicle or the like, and a U-phase current I _U , a V-phase current I _V , and a W-phase current I _W that are different in phase by 120 ° flow. . The current sensor 1 is configured to measure the current I _U , the current I _V , and the current I _W.

  As shown in FIGS. 1A and 1B, the current sensor 1 has a ring shape in which a bus bar 3 that generates a magnetic field around a current to be detected and a gap 40 formed in part are formed. And a plurality of current sensor units 2 including a core 4 into which the bus bar 3 is inserted at the center of the ring and a magnetic sensor 5 disposed in the gap 40 and detecting a change in the magnetic field in the gap 40. A plurality of current sensor units 2 are further integrated and schematically configured.

  In the current sensor 1, as shown in FIG. 1A, a plurality of current sensor units 2 are integrated by a main body 10. As an example, a printed wiring board 12 is disposed on the upper portion of the main body 10. However, the present invention is not limited thereto, and a lead frame that is electrically connected to the terminals of the magnetic sensor 5 of the current sensor unit 2 is disposed. May be. For example, the wiring formed on the printed wiring board 12 is electrically connected to a terminal of the magnetic sensor 5 and is electrically connected to an external device. The interval between the current sensor units 2 is determined based on, for example, the interval between the current paths through which the current to be detected flows. This current path is electrically connected to the bus bar 3.

  The main body 10 is preferably made of, for example, a material excellent in insulation and moisture resistance, and is formed using a synthetic resin material such as polyphenylene sulfide (PPS) resin, acrylonitrile / butadiene / styrene (ABS) resin. The main body 10 according to the present embodiment is formed by insert molding using ABS resin. Specifically, the main body 10 is formed by pouring a molten resin between a cavity in which a plurality of current sensor units 2 are arranged and a core paired with the cavity, and the resin is cured. . The plurality of current sensor units 2 are integrated by this insert molding.

(Configuration of current sensor unit 2)
For example, as shown in FIG. 1B, the current sensor unit 2 includes a bus bar 3, a core 4, and a magnetic sensor 5 that are integrated by insert molding. The molten resin poured at the time of insert molding is solidified to form the main body 20.

  The current sensor unit 2 is integrated with the bus bar 3, the core 4 and the magnetic sensor 5 being positioned. That is, the current sensor unit 2 is configured so that the current flowing through the bus bar 3 can be detected by the magnetic sensor 5.

  Therefore, the current sensor unit 2 is in a state where electrical adjustments such as sensitivity and offset voltage are performed.

(Configuration of bus bar 3)
The bus bar 3 is formed, for example, by punching a conductive plate member such as copper, a copper alloy, and brass so as to have a long and thin plate shape. The shape of the bus bar 3 is not limited to a plate shape, and may be an arbitrary shape.

(Configuration of core 4)
FIG. 2 is a schematic diagram of the core according to the first embodiment. In FIG. 2, it is assumed that the current 30 flows from the front side of the sheet of FIG. Accordingly, the magnetic field 8 is generated clockwise on the paper surface of FIG. 2, and a part of the magnetic field 8 forms a magnetic path 80 inside the core 4.

  As shown in FIG. 2, the core 4 has an insertion hole 43 into which the bus bar 3 is inserted. The core 4 has a shape in which a part of the ring shape is cut off. As an example, the core 4 is formed by stacking a plurality of plate-like cores having a plate shape. The plate-like core is formed using a soft magnetic material such as permalloy, an electromagnetic steel plate, or ferrite, for example.

  Specifically, the first end surface 41 and the second end surface 42, which are the end portions of a portion where a part of the ring shape is cut off, are formed in the major axis direction of the core 4. The magnetic sensor 5 is disposed in the gap 40 surrounded by the first end surface 41 and the second end surface 42.

  The arrangement of the magnetic sensor 5 is such that the magnetic field lines of the magnetic field 8 between the first end surface 41 and the second end surface 42 and the detection surface of the magnetic sensor 5 are substantially perpendicular to each other. Preferably, it is done. The magnetic sensor 5 is configured to output a signal based on the magnetic lines of force that spring out from the first end face 41 and the second end face 42 and are sucked.

(Configuration of magnetic sensor 5)
The magnetic sensor 5 includes, for example, a terminal 51, a terminal 52, and a terminal 53. The terminal 51 is electrically connected to GND, for example. For example, the terminal 52 is a terminal to which a voltage necessary for the current sensor 1 to operate is supplied. The terminal 53 is a terminal that outputs a detection signal. The terminal 51, the terminal 52, and the terminal 53 are formed using, for example, a conductive metal material such as gold or copper, or an alloy material thereof. Note that “electrically connected to GND” means, for example, connection to the Lo output side having low impedance.

  The magnetic sensor 5 is a sensor that outputs a detection signal corresponding to the strength of the magnetic field, such as a Hall sensor.

(Manufacture of current sensor 1)
First, as many current sensor units 2 as necessary are prepared. In the present embodiment, as an example, three current sensor units 2 are prepared.

  Next, the three current sensor units 2 are disposed in the cavity, and molten resin is injected between the cavity and the core that is paired with the cavity. After the temperature is lowered and the molten resin is cured, the current sensor 1 is obtained by taking out from the cavity.

(Effects of the first embodiment)
The current sensor 1 according to the present embodiment can flexibly cope with changes in the number of currents to be detected. Specifically, the current sensor 1 can be obtained by integrating a plurality of current sensor units 2 manufactured in advance and electrically adjusted according to the number of currents to be detected by insert molding. . Therefore, the current sensor 1 achieves the positioning accuracy required by the current sensor unit 2 unit and matches the electrical characteristics as compared with the case where the plurality of bus bars, cores, and magnetic sensors are integrated after positioning. And the like, and can flexibly cope with changes in the number of currents to be detected. Furthermore, since the current sensor 1 can determine the interval of the current sensor unit 2 in accordance with the interval of the current path through which the current to be detected flows, the current sensor 1 can flexibly cope with a change in the arrangement of the current path.

  In addition, even if the number of currents to be measured and the arrangement of the current paths are changed, the current sensor 1 only needs to change the number and interval of the current sensor units 2 to be prepared. The time spent investigating the structure is reduced, the manufacturing cost is reduced, and the manufacturing period is further reduced.

  The current sensor 1 is manufactured at a low cost because the parts used for the current sensor unit 2 are the same, so that the unit price is low. Furthermore, the capital investment for manufacturing the current sensor 1 is suppressed.

  Since the current sensor 1 is manufactured using the current sensor unit 2 that has been subjected to accuracy inspection, electrical adjustment, and the like for each current sensor unit 2, the plurality of bus bars, cores, and magnetic sensors are positioned and integrated. Compared with the case where it is said, the fall of the precision resulting from manufacture is suppressed and a yield improves.

[Second Embodiment]
The second embodiment is different from the first embodiment in that a plurality of current sensor units 2 arranged in the case 7 are integrated.

  FIG. 3A is an exploded perspective view of the current sensor according to the second embodiment, and FIG. 3B is a top view of the current sensor. In the following embodiments, portions having the same functions and configurations as those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and description thereof is omitted.

  In the current sensor 1 according to the present embodiment, for example, as shown in FIGS. 3A and 3B, a plurality of current sensor units 2 and respective bus bars 3 of the plurality of current sensor units 2 are inserted. A case 7 having a plurality of slits 75, and a plurality of current sensor units 2 inserted and attached to the slits 75 of the case 7 and a filler 9 filled between the cases 7 are schematically configured. Yes.

  In the case 7, a plurality of slits 75 are formed in the first side surface portion 70 and the second side surface portion 71 that form a pair. The slit 75 is configured such that the bus bar 3 of the current sensor unit 2 is inserted. The case 7 is formed using a synthetic resin material such as polypropylene, polystyrene, polyethylene, polyamide, acrylonitrile / butadiene / styrene (ABS), for example.

  In the case 7, the interval between the slits 75 is equal to or greater than the interval between the bus bars 3 when the current sensor unit 2 is brought into contact. That is, in the case 7, for example, the slits 75 are formed in accordance with the interval of the current path through which the current to be detected flows.

  As an example, the filler 9 is a potting agent such as silicone or polyurethane. The filler 9 is filled between the case 7 and the current sensor unit 2 in a state where the current sensor unit 2 is attached to the case 7. The filler 9 is not limited to a potting agent, and may be any material that can be filled between the case 7 and the current sensor unit 2 and hardens after a lapse of time.

  The filler 9 is filled in the case 7 that is protected so as not to leak from the slit 75, for example. Accordingly, as shown in FIG. 3B, the filler 9 is filled in the gap above the slit 75 in which the bus bar 3 is inserted. In FIG. 3B, the current sensor 1 is not filled with the filler 9 from the terminal 51 to the terminal 53 side of the current sensor unit 2, but may be filled with the filler 9 as the upper part is covered. . The current sensor 1 may be filled so as to cover the printed wiring board 12 by arranging the printed wiring board 12 on the current sensor unit 2. The filling amount of the filler 9 is not limited to these, and is arbitrary depending on the application.

(Effect of the second embodiment)
In the current sensor 1 according to the present embodiment, a plurality of current sensor units 2 manufactured in advance and electrically adjusted according to the number of currents to be detected are arranged in a case 7, and a filler 9 It is united using. Therefore, the current sensor 1 achieves the positioning accuracy required by the current sensor unit 2 unit and matches the electrical characteristics as compared with the case where the plurality of bus bars, cores, and magnetic sensors are integrated after positioning. In addition, it is possible to flexibly cope with changes in the number of currents to be detected and the arrangement of current paths.

[Third Embodiment]
The third embodiment is different from the above-described embodiments in that a mounting portion 76 is provided on the case 7.

  FIG. 4A is an exploded perspective view of the current sensor according to the third embodiment as viewed from the side, and FIG. 4B is a cross-sectional view of the main part for explaining the mounting portion of the current sensor.

  For example, as shown in FIGS. 4A and 4B, the current sensor 1 according to the present embodiment includes a plurality of slits 75 into which the respective bus bars 3 of the plurality of current sensor units 2 are inserted, and a plurality of currents. A case 7 having a plurality of attachment portions 76 to which each of the sensor units 2 is attached is schematically configured.

  As shown in FIGS. 4A and 4B, the case 7 has attachment portions 76 formed on both sides of the slits 75 of the first side surface portion 70 and the second side surface portion 71 that form a pair. The current sensor unit 2 has a plurality of recesses 61 formed at positions corresponding to the mounting portions 76.

  The attachment portion 76 is roughly configured to include an elongated plate-shaped plate portion 77 formed by cutting out a side surface portion, and a convex portion 78 formed at the tip portion thereof. For example, as shown in FIG. 4B, the plate portion 77 is configured to incline toward the inside of the case 7.

  When the current sensor unit 2 is inserted into the case 7, the convex portion 78 comes into contact with the side surface of the current sensor unit 2, so that the plate portion 77 bends outward of the case 7. When the current sensor unit 2 is further inserted into the case 7, the convex portion 78 of the mounting portion 76 is fitted into the concave portion 61 of the current sensor unit 2 based on the elastic force of the plate portion 77, and the current sensor unit 2 is 7 is attached.

  The shape of the attachment portion 76 is not limited to the above example, and may be any shape as long as the current sensor unit 2 is attached to the case 7. The attachment portion 76 is formed in accordance with the slit 75 formed based on the arrangement of current paths through which the current to be detected flows.

  Further, the current sensor 1 may be configured such that the current sensor unit 2 and the case 7 are integrated using a potting agent after the current sensor unit 2 is attached to the case 7.

(Effect of the third embodiment)
Since the current sensor 1 according to the present embodiment is provided with the attachment portion 76 in the case 7, the current sensor unit 2 and the case 7 can be easily integrated.

  According to the current sensor 1 of at least one embodiment described above, it is possible to flexibly cope with changes in the number of currents to be detected, the arrangement of current paths, and the like.

  As mentioned above, although some embodiment and modification of this invention were demonstrated, these embodiment and modification are only examples, and do not limit the invention based on a claim. These novel embodiments and modifications can be implemented in various other forms, and various omissions, replacements, changes, and the like can be made without departing from the scope of the present invention. In addition, not all combinations of features described in these embodiments and modifications are necessarily essential to the means for solving the problems of the invention. Furthermore, these embodiments and modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 ... Current sensor 2 ... Current sensor unit 3 ... Bus bar 4 ... Core 5 ... Magnetic sensor 7 ... Case 8 ... Magnetic field 9 ... Filler 10 ... Main body 12 ... Printed wiring board 20 ... Main body 30 ... Current 40 ... Gap 41 ... First End surface 42 ... second end surface 43 ... insertion hole 51 ... terminal 52 ... terminal 53 ... terminal 61 ... concave 70 ... first side surface 71 ... second side surface 75 ... slit 76 ... mounting portion 77 ... plate portion 78 ... convex part 80 ... magnetic path

Claims (4)

  A bus bar that generates a magnetic field around a current to be detected flows, a ring shape in which a gap is formed in a part, a core in which the bus bar is inserted in the center of the ring, and the gap, A current sensor in which a plurality of current sensor units integrated with a magnetic sensor for detecting a change in the magnetic field in the gap are integrated, and the plurality of current sensor units are further integrated. A case having a plurality of slits into which the respective bus bars of the plurality of current sensor units are inserted;
A plurality of the current sensor units attached by being inserted into the slits of the case and a filler filled between the cases;
The current sensor according to claim 1, comprising:   The current sensor according to claim 1, further comprising a case having a plurality of slits into which the bus bars of the plurality of current sensor units are inserted, and a plurality of attachment portions to which the plurality of current sensor units are respectively attached.   4. The current sensor according to claim 2, wherein the case has an interval between the slits equal to or greater than an interval between the bus bars when the current sensor unit is in contact with the case. 5.

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