JP2021032796A - Current sensor - Google Patents

Abstract

To provide a current sensor with which it is possible to fix the position of a busbar in a tube unit without damaging a portion of the busbar that is tightened by a bolt.SOLUTION: A busbar 100 includes a slit 110. The slit 110 is provided at a position out of a bolt-tightening range of one face 101 among outer edges 104, 105 that are widthwise edges perpendicular to one direction in the surface direction of one face 101 of the busbar 100. A tube part 202 includes a snap fit 210. The snap fit 210 is provided at a position of one opening 206 of the tube part 202 that corresponds to outer edges 104, 105 where one end 102 side of the busbar 100 protrudes. The snap fit 210 protrudes in the opening direction of the one opening 206 of the tube part 202. The position of the busbar 100 is secured due to that a pawl 212 of the snap fit 210 is caught by the slit 110.SELECTED DRAWING: Figure 1

Description

The present invention relates to a current sensor.

Conventionally, for example, Patent Document 1 has proposed a current sensor that detects a current flowing through a plate-shaped bus bar. The busbar has one side. The current sensor includes a detector located above one side of the bus bar. The detection unit is housed in a resin case.

Japanese Unexamined Patent Publication No. 2015-194472

As the conventional current sensor, a configuration in which a bus bar is fixed to a case is known. Specifically, the bus bar is a straight line along one direction parallel to one surface. The current flows in one direction. Further, the bus bar has two through holes provided at the center position in the width direction perpendicular to one direction on one surface. One through hole is provided at one end of the bus bar. The other through hole is provided between one end and the other end of the bus bar.

On the other hand, the case has a pipe through which the bus bar is passed. A snap fit along one direction of the bus bar is provided at the center position in the width direction of the bus bar in one opening of the pipe portion. The snap fit has a claw at the tip.

In the above configuration, the busbar is inserted at one end into the other opening of the tube. Also, the other through hole of the bus bar moves to the position of the snap-fit claw. Then, the claw portion is caught in the other through hole portion. Therefore, the position of the bus bar in the pipe portion is fixed.

However, as the busbar moves inside the tube, the snap-fit claws come into contact with one side of the busbar. Therefore, as the bus bar moves, the claws damage one surface of the bus bar. Since the snap fit is centered in the width direction of the bus bar, scratches are made at the center of the width direction of the bus bar from the tip of the bus bar to the other through hole.

That is, the scratch is also made when passing through one of the through holes. If one of the through holes is scratched, the contact resistance when the conductor is bolted to the one through hole changes.

In view of the above points, it is an object of the present invention to provide a current sensor capable of fixing the position of the bus bar in the pipe portion without damaging the bolted portion of the bus bar.

In order to achieve the above object, in the invention of claim 1, the current sensor includes a bus bar (100) and a case (200). The bus bar has a plate shape having one surface (101) and a straight line along one direction parallel to one surface. The bus bar has one end on one end (102) in one direction, the other end (103) on the other end in one direction, and a through hole (108) provided at one end and bolted. Have.

The case has a tube section (202) and a housing section (203). A part of the pipe portion is arranged between one end portion and the other end portion so that the pipe portion is passed through the hollow portion from the side of one end portion of the bus bar and the through hole portion of the bus bar is exposed. The accommodating unit accommodates a detection unit (300) that detects a current flowing through the bus bar.

The bus bar has hooks (110, 111, 112). The hooking portion is provided at a position outside the bolt tightening range on one surface of the outer edge portions (104, 105) which are end portions in the width direction perpendicular to one direction in the surface direction of one surface.

The tube section has a snap fit (210). The snap fit is provided at a position corresponding to the outer edge of the one opening (206) in which the side of one end of the bus bar protrudes, and also protrudes in the opening direction of the one opening. The snap fit fixes the position of the bus bar in the opening direction by hooking the claw portion (212) on the hook portion.

According to this, the snap fit and the hooking portion are provided at positions outside the bolt tightening range with respect to the through hole portion. Therefore, when the bus bar is passed from the side of one end of the bus bar to the pipe portion, the claw portion of the snap fit slides at a position outside the bolt tightening range with respect to the through hole portion. Therefore, the position of the bus bar in the pipe portion can be fixed without damaging the bolted through hole portion of the bus bar.

The reference numerals in parentheses of each means described in this column and in the claims indicate the correspondence with the specific means described in the embodiments described later.

It is a perspective view of the current sensor which concerns on 1st Embodiment. It is a transmission perspective view of the current sensor shown in FIG. It is a figure which showed the process of assembling a bus bar to a case. It is a perspective view which showed the modification of the current sensor which concerns on 1st Embodiment. It is a perspective view of the current sensor which concerns on 2nd Embodiment. It is a perspective view which showed the modification of the current sensor which concerns on 2nd Embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each of the following embodiments, parts that are the same or equal to each other are designated by the same reference numerals in the drawings.

(First Embodiment)
Hereinafter, the first embodiment will be described with reference to the drawings. As shown in FIGS. 1 and 2, the current sensor 1 includes a bus bar 100, a case 200, a detection unit 300, and a filler 400.

The bus bar 100 has a plate shape having one side 101. The bus bar 100 is a linear wiring component along one direction parallel to one surface 101. A current to be measured flows through the bus bar 100. The bus bar 100 has one end 102, the other end 103, and outer edges 104, 105.

The one end 102 is an end on one end side of the bus bar 100 in one direction. The other end 103 is the other end of the bus bar 100 in one direction. One end 102 of the bus bar 100 is connected to, for example, an inverter device. The other end 103 of the bus bar 100 is connected to a load device such as a motor.

The outer edge portions 104 and 105 are end portions in the width direction perpendicular to one direction in the surface direction of one surface 101 of the bus bar 100. The outer edges 104 and 105 include sides 106 and 107 of the bus bar 100. The side surfaces 106 and 107 of the bus bar 100 are connected to one side 101 and are surfaces along one direction.

Through holes 108 and 109 are formed in one end 102 and the other end 103. The through holes of the through hole portions 108 and 109 have a circular shape on one surface 101. The center of the through hole of the through hole portions 108 and 109 on the one surface 101 is located at the center in the width direction perpendicular to one direction in the surface direction of the one surface 101 of the bus bar 100. Other wiring components such as conductors are bolted to the through holes 108 and 109. When tightening bolts, conductors, washers, etc. come into contact with through holes 108 and 109. The range of contact with the conductor, washer, etc. on one side 101 of the bus bar 100 corresponds to the bolt tightening range.

The case 200 has the appearance of the current sensor 1. The case 200 is a molded resin material. The appearance of the case 200 is a rectangular parallelepiped. Specifically, the case 200 is a bottomed tubular having an opening 201. The case 200 has a pipe portion 202, an accommodating portion 203, and a connector portion 204.

The pipe portion 202 is a portion where the bus bar 100 is arranged. The tube portion 202 is formed in a flat shape. The tube portion 202 is integrated with the bottom portion 205 of the case 200. The opening direction of one opening 206 of the pipe portion 202 is directed to the same direction as the opening direction of the opening 201 of the case 200.

One end 102 of the bus bar 100 is inserted through the other opening of the pipe 202. Then, one end 102 of the bus bar 100 passes through the hollow portion of the pipe 202. Further, a part between one end 102 and the other end 103 of the bus bar 100 is arranged in the pipe 202 so that the entire through holes 108 and 109 of the bus bar 100 are exposed from the pipe 202. ..

A press-fitting portion 207 is provided on the bottom portion 205 of the bus bar 100. The press-fitting portion 207 is located around the other opening of the pipe portion 202. The press-fitting portion 207 fixes the bus bar 100 to the pipe portion 202 by press-fitting a part of the bus bar 100 in a state where the bus bar 100 is passed through the pipe portion 202.

The accommodating portion 203 is a space portion provided in the case 200. The accommodating portion 203 is formed by denting a portion of the case 200 excluding the portion constituting the pipe portion 202. The accommodating portion 203 is provided around the pipe portion 202. The accommodating unit 203 accommodates the detection unit 300. The accommodating portion 203 is connected to an opening 209 provided in one side portion 208 of the case 200.

The connector unit 204 is a connection unit for electrically connecting the detection unit 300 and the outside. The connector portion 204 protrudes from the side portion 208 of the case 200. The connector of the wiring is connected to the connector portion 204.

The detection unit 300 detects the current flowing through the bus bar 100. The detection unit 300 has a core 301 and a substrate unit 302.

The core 301 is a component that generates a magnetic flux in the core 301 when a current to be measured flows through the hollow portion. The core 301 has a shape in which one end side and the other end side of one plate material are arranged to face each other with a constant magnetic gap. As the core 301, a magnetic material such as permalloy is used. The pipe portion 202 is located in the hollow portion of the core 301. The core 301 is accommodated in the accommodating portion 203 via the opening 201 of the case 200. The core 301 is accommodated in the accommodating portion 203 with the magnetic gap directed toward the opening 209 of the case 200.

The board portion 302 is a board on which a Hall IC for detecting the magnitude of the magnetic flux generated in the core 301, a circuit chip for processing a signal from the Hall IC, and the like are mounted on the board. The Hall IC is arranged in the magnetic gap of the core 301. The substrate portion 302 is accommodated in the accommodating portion 203 via the opening 209 of the case 200. In the present embodiment, the accommodating portion 203 is separated into a room for accommodating the core 301 and a room for accommodating the substrate portion 302.

The filler 400 is a sealing member filled in the accommodating portion 203 with the core 301 and the substrate portion 302 accommodated in the accommodating portion 203 of the case 200. As the filler 400, a material such as urethane is used. The surface of the filler 400 filled in the accommodating portion 203 is exposed to the openings 201 and 209 of the case 200. The above is the overall configuration of the current sensor 1 according to the present embodiment.

Next, fixing the position of the bus bar 100 with respect to the pipe portion 202 of the case 200 will be described. First, the bus bar 100 has a slit 110. The slit 110 is a portion in which a part of the outer edge portions 104 and 105 is recessed along the width direction of the bus bar 100. That is, the slit 110 is a notch portion provided along the width direction of the bus bar 100.

In this embodiment, the slits 110 are provided on both the outer edges 104 and 105. Therefore, the bus bar 100 has a partially constricted shape. Further, the slit 110 is provided at a position outside the bolt tightening range on one surface 101 of the outer edge portions 104 and 105 of the bus bar 100.

On the other hand, the pipe portion 202 has a snap fit 210. The snap fit 210 is provided in the opening 206 of the bus bar 100 on which the side of one end 102 projects. The snap fit 210 is provided at a position corresponding to the outer edges 104 and 105 of the bus bar 100. The snap fit 210 projects in the opening direction of one opening 206.

Specifically, the snap fit 210 is provided at the opening end portion 211 corresponding to the side surfaces 106 and 107 of the bus bar 100 in the one opening 206 of the pipe portion 202. The snap fit 210 is arranged to face the side surfaces 106 and 107 of the bus bar 100. That is, the current sensor 1 has two sets of the snap fit 210 and the slit 110.

Further, the snap fit 210 has a claw portion 212 at the tip portion thereof. The claw portion 212 projects toward the bus bar 100. Then, in the snap fit 210, the claw portion 212 is caught in the slit 110. The slit 110 is a hooking portion on which the claw portion 212 of the snap fit 210 is hooked. The position of the bus bar 100 in the opening direction is fixed by the claw portion 212 of the snap fit 210 being caught in the slit 110 of the bus bar 100. The above is the overall configuration of the current sensor 1 according to the present embodiment.

Next, the current detection method of the current sensor 1 will be described. When a current flows through the bus bar 100 of the current sensor 1, a magnetic flux corresponding to the magnitude of the current is generated in the core 301. In addition, this magnetic flux leaks into the magnetic gap. Then, the magnetic flux leaking into the magnetic gap is detected by the Hall IC. Further, the substrate portion 302 processes a signal corresponding to the magnitude of the magnetic flux detected by the Hall IC. In this way, the magnitude of the current is detected. The signal corresponding to the magnitude of the current detected by the current sensor 1 is output to the outside via the connector portion 204.

Next, a method of manufacturing the current sensor 1 will be described. First, the bus bar 100 and the case 200 are prepared. Then, the bus bar 100 is assembled to the pipe portion 202 of the case 200. Specifically, as shown in FIG. 3, the bus bar 100 is passed from the side of one end 102 through the hollow portion of the pipe 202. When the bus bar 100 is moved and one end 102 of the bus bar 100 is projected from one opening 206 of the pipe portion 202, the claw portions 212 of the snap fit 210 come into contact with the side surfaces 106 and 107 of the bus bar 100.

After that, the bus bar 100 is further moved to press-fit the protruding portion 111 provided in the bus bar 100 into the press-fitting portion 207 of the case 200, and hook the claw portion 212 of the snap fit 210 into the slit 110 of the bus bar 100. As a result, the bus bar 100 is fixed to the case 200, and the position of the bus bar 100 with respect to the pipe portion 202 is fixed.

A part between the one end 102 and the other end 103 of the bus bar 100 is arranged in the pipe portion 202 by the snap fit 210, so that the entire through holes 108 and 109 of the bus bar 100 are exposed from the pipe portion 202. It becomes a state. Since the claw portion 212 of the snap fit 210 slides on the side surfaces 106 and 107 of the bus bar 100, one surface 101 of the bus bar 100 is not scratched by the contact of the claw portion 212.

Subsequently, the core 301 is installed in the accommodating portion 203 via the opening 201 of the case 200. Further, the substrate portion 302 is installed in the accommodating portion 203 via the opening 209 of the case 200. Note that FIG. 3 shows a shape in which the accommodating portion 203 accommodating the core 301 and the accommodating portion 203 accommodating the substrate portion 302 are separated, which is an example of the shape of the case 200. As described above, the accommodating portion 203 accommodating the core 301 and the accommodating portion 203 accommodating the substrate portion 302 may be connected.

Then, the filler 400 is poured into the accommodating portion 203 through the openings 201 and 209 of the case 200. As a result, the accommodating portion 203 is sealed with the filler 400. In this way, the current sensor 1 is completed.

As described above, the snap fit 210 and the slit 110 are provided at positions outside the range of bolt tightening with respect to the through hole portion 108 of the bus bar 100. Therefore, when the bus bar 100 is passed through the pipe portion 202 from the side of the one end portion 102, the claw portion 212 of the snap fit 210 slides at a position outside the bolt tightening range with respect to the through hole portion 108 of the bus bar 100. In this embodiment, the claw portion 212 slides on the side surfaces 106 and 107 of the bus bar 100. Therefore, the position of the bus bar 100 in the pipe portion 202 can be fixed without damaging the bolted through hole portion 108 of the bus bar 100. Since the bus bar 100 is not scratched, the quality of the bus bar 100 can be improved.

Further, it is not necessary to provide the bus bar 100 with a through hole for hooking the claw portion 212 of the snap fit 210. Therefore, damage to the press working die when manufacturing the bus bar 100 can be suppressed. Therefore, productivity can be improved. Since the bus bar 100 is not provided with a through hole, the thickness of the bus bar 100 can be increased.

Regarding the correspondence between the description of the present embodiment and the description of the claims, the slit 110 corresponds to the "hooking portion" of the claims.

As a modification, the snap fit 210 and the slit 110 may be paired as one set. Since the snap fit 210 and the slit 110 are configured not for fixing the bus bar 100 but for aligning the bus bar 100, in order to ensure the accuracy of the alignment, the snap fit 210 and the slit 110 are combined. Is preferably two sets.

As a modification, the through holes 108 and 109 of the bus bar 100 do not have to be located at the center in the width direction. The slit 110 of the bus bar 100 may be provided at a position outside the bolt tightening range of the one side 101.

As a modification, as shown in FIG. 4, the bus bar 100 may have a groove 111 instead of the slit 110. The groove portion 111 is not a portion through which a part of the bus bar 100 penetrates, but a portion in which a part of the outer edge portions 104 and 105 of the bus bar 100 is recessed. For example, the groove portion 111 is a hole portion in which a part of the side surfaces 106 and 107 of the bus bar 100 is recessed. Therefore, the claw portion 212 of the snap fit 210 is caught in the groove portion 111 of the bus bar 100.

(Second Embodiment)
In this embodiment, a part different from the first embodiment will be mainly described. As shown in FIG. 5, the snap fit 210 is provided at the widthwise end of the opening end 213 corresponding to one side 101 of the bus bar 100 in one opening 206 of the pipe 202. Further, the snap fit 210 is arranged so as to face one side 101 of the bus bar 100. Then, the claw portion 212 of the snap fit 210 projects toward the one side 101 of the bus bar 100.

In the above configuration, when the bus bar 100 is passed through the hollow portion of the pipe portion 202 from the side of the one end portion 102, the claw portion 212 of the snap fit 210 comes into contact with the widthwise end of the one surface 101 of the bus bar 100. When the bus bar 100 moves with respect to the pipe portion 202, the claw portion 212 slides on one side 101 of the bus bar 100 and is caught in the slit 110.

Here, the claw portion 212 of the snap fit 210 slides at a position outside the bolt tightening range with respect to the through hole portion 108 of the one surface 101 of the bus bar 100. Therefore, the position of the bus bar 100 in the pipe portion 202 can be fixed without damaging the bolted through hole portion 108 of the bus bar 100.

As a modification, as shown in FIG. 6, the bus bar 100 may have a groove 112 instead of the slit 110. The groove portion 112 is a portion in which a part of one surface 101 of the bus bar 100 is recessed, similarly to the groove portion 111. The groove portion 112 may be formed in a hole shape. Therefore, the claw portion 212 of the snap fit 210 is caught in the groove portion 112 of the bus bar 100.

(Other embodiments)
The configuration of the current sensor 1 shown in each of the above embodiments is an example, and the configuration is not limited to the configuration shown above, and other configurations capable of realizing the present invention can be used. For example, the appearance of the current sensor 1 is not limited to the rectangular parallelepiped shape. The appearance of the current sensor 1 may be polygonal, columnar, or elliptical.

100 Bus bar, 101 one side, 102 one end, 103 other end, 104, 105 outer edge, 106, 107 side, 108 through hole, 110 slit, 111, 112 groove, 200 case, 202 pipe, 203 accommodating part, 206 One opening, 210 snap fit, 211 opening end, 212 claw, 213 opening end, 300 detector

Claims (5)

It has a plate shape having one surface (101) and a linear shape along one direction parallel to the one surface, and one end portion (102) on one end side in the one direction and the other end on the other end side in the one direction. A bus bar (100) having a portion (103) and a through hole portion (108) provided at one end and tightened with bolts.
A part between the one end and the other end is arranged so that the through hole of the bus bar is exposed while being passed through the hollow portion from the side of the one end of the bus bar. A case (200) having a pipe portion (202) and an accommodating portion (203) accommodating a detection unit (300) for detecting a current flowing through the bus bar.
Including
The bus bar is a hook provided at a position outside the bolt tightening range on the one surface of the outer edge portions (104, 105) which are ends in the width direction perpendicular to the one surface in the surface direction of the one surface. Has parts (110, 111, 112)
The pipe portion is provided at a position corresponding to the outer edge portion of the one opening (206) on which the one end side of the bus bar protrudes, and also protrudes in the opening direction of the one opening. , A current sensor having a snap fit (210) that fixes the position of the bus bar in the opening direction by hooking the claw portion (212) on the hook portion. The current sensor according to claim 1, wherein the hooked portion is a slit (110) in which a part of the outer edge portion is recessed along the width direction. The current sensor according to claim 1, wherein the hooked portion is a groove portion (111, 112) in which a part of the outer edge portion is recessed. The busbar is connected to the one side and has sides (106, 107) along the one direction.
The snap fit is provided at the opening end (211) corresponding to the side surface of the one opening and is arranged to face the side surface, and the claw portion projects toward the side surface and the hooking portion. The current sensor according to any one of claims 1 to 3, which is hooked on the current sensor. The snap fit is provided at the end in the width direction at the opening end (213) corresponding to the one surface of the one opening and is arranged to face the one surface, and the claw portion is located on the one surface side. The current sensor according to any one of claims 1 to 3, which protrudes and is caught in the hooked portion.

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