JP2020136458A - Shunt resistor mounting structure - Google Patents

Abstract

To make a mounting structure that uses a shunt resistor as a current sensor smaller (lower in height).SOLUTION: A shunt resistor mounting structure in which a shunt resistor is mounted on a pattern built-in board that has a built-in voltage signal extraction pattern is defined by a through hole formed in the thickness direction of the pattern built-in board, and is provided with an accommodating portion that accommodates at least a part of the resistor provided between a first terminal and a second terminal that are sequentially provided from the side opposite to the mounting side of the shunt resistor.SELECTED DRAWING: Figure 1

Description

The present invention relates to a mounting structure for a shunt resistor.

For example, a shunt resistor is used to detect a current in a semiconductor power module or the like mounted on an electric vehicle. Patent Document 1 describes a shunt resistor that is easy to install, does not require an excessive installation space, and can detect current with high accuracy.

The shunt resistor described in Patent Document 1 is made of a conductive metal material and has a first plane and a second plane, and a first terminal and a second terminal each having an outer peripheral surface around the first plane and the first terminal. And the first planes of the second terminal are opposed to each other, and a resistor connected to each first plane to connect the first terminal and the second terminal, and the resistor. The joint area with each of the first planes is smaller than the area of the first plane, and the first terminal and the second terminal have holes penetrating from the first plane to the second plane. The part is formed. Hereinafter, a shunt resistor having such a structure is also referred to as a “shunt (resistor)”.

JP-A-2017-212297

The shunt resistor described in Patent Document 1 uses a structure in which an output signal voltage extraction terminal is drawn out from each side surface of the first terminal and the second terminal. By the way, in the shunt described in Patent Document 1, the resistance value can be adjusted by adjusting the diameter and length of the resistor serving as a support.

Inverters are used in various vehicles such as electric vehicles, electric boats, and recently flying vehicles (large drones). Miniaturization is an important factor in these moving bodies and the like. Miniaturization of the current sensor is also desired, and a bushing shunt (see Patent Document 1) that can be used in a high temperature environment by integrating mechanical and electrical devices is particularly useful.

An object of the present invention is to reduce the size (reduction in height) of a mounting structure using a shunt resistor as a current sensor.

According to one aspect of the present invention, it is a mounting structure of a shunt resistor in which a shunt resistor is mounted on a pattern-embedded substrate having a built-in voltage signal extraction pattern, and a penetration formed in the thickness direction of the pattern-embedded substrate. An accommodating portion is provided that accommodates at least a part of the resistor defined by the holes and provided between the first terminal and the second terminal in order from the side opposite to the mounting side of the shunt resistor. The shunt resistor mounting structure provided is provided.

The through hole defining the accommodating portion has a size that allows the resistor to be inserted, and is a wiring current that also serves as the second terminal (lower terminal) of the shunt resistor below the pattern-embedded substrate. It is preferable that the bar is arranged.

It is preferable that a metal material having a resistivity lower than that of the resistor is connected to the second terminal side of the resistor, and the metal material and the wiring current bar are connected to each other.

The through hole defining the accommodating portion preferably has a size that allows the insertion of the second terminal.

It is preferable that the second terminal is connected to the wiring current bar.

It is preferable that the bus bar is arranged on the first terminal side of the shunt resistor and provided with a fixing means for fixing the bus bar and the first terminal.

The fixing means may further fix the pattern-embedded substrate and the wiring current bar.

According to the present invention, it is possible to reduce the size of the mounting structure of the current detector integrated with the large current substrate.

It is an exploded perspective view which shows the mounting structure of the shunt resistor according to 1st Embodiment of this invention. It is a side sectional view of the mounting structure (fixed structure). It is a perspective view which shows the structural example of the substrate (FIG. 3A) and the voltage signal extraction pattern (FIG. 3B). It is an exploded perspective view which shows the mounting structure of the shunt resistor by the 2nd Embodiment of this invention. It is a side sectional view of the mounting structure (fixed structure). It is an exploded perspective view which shows the mounting structure of the shunt resistor according to the 3rd Embodiment of this invention. It is a side sectional view of the mounting structure (fixed structure). It is a perspective view which shows one structural example of the substrate (FIG. 8A) and the voltage signal extraction pattern (FIG. 8B) built in the substrate by this embodiment. It is an exploded perspective view which shows the mounting structure of the shunt resistor according to the 4th Embodiment of this invention. FIG. 10A is an exploded perspective view (viewed from below) showing the mounting structure of the shunt resistor according to the fourth embodiment of the present invention, and FIG. 10B is a bottom surface seen from below. It is a figure. It is a perspective view seen from the lower surface side of the mounting structure according to 4th Embodiment of this invention. It is a perspective view which shows one configuration example of the current drawing part by this embodiment. It is sectional drawing which shows the mounting structure (fixed structure) of the shunt resistor by this embodiment. FIG. 13A is a diagram showing a structure in which the tip of the resistor is formed of the resistance material. FIG. 13B is a diagram showing a structure in which a conductive material is connected to the tip of the resistor.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(First Embodiment)
FIG. 1 is an exploded perspective view showing a mounting structure of a shunt resistor according to the first embodiment of the present invention, and FIG. 2 is a side sectional view of the mounting structure (fixed structure). FIG. 3 is a perspective view of a configuration example of the substrate (FIG. 3 (a)) and the voltage signal extraction pattern (FIG. 3 (b)).

As shown in FIGS. 1 and 2, the shunt resistor mounting structure X according to the present embodiment incorporates the shunt resistor A and a voltage signal extraction pattern arranged on the mounting surface side (lower part of the figure). It has a board with a built-in voltage signal extraction pattern (hereinafter, referred to as “board”) 51.

The shunt resistor A is composed of, for example, a first terminal (electrode) 1 and a second terminal (electrode) 3, and a plurality of, for example, columnar resistors 5 provided so as to intervene between them. The joint area between the resistor 5 and the first terminal (electrode) 1 and the second terminal (electrode) 3 is smaller than the area of the terminal itself. This structure is also referred to as a bushing shunt structure. The first terminal 1 and the second terminal 3 are made of a conductive metal material such as Cu. The resistor 5 is made of a metal material (alloy) such as Cu—Ni-based, Cu—Mn-based, or Ni—Cr-based, which has a higher resistivity than the terminal.

In the shunt resistor A shown in FIG. 1, the area of the first terminal (electrode) 1 (for example, a square having a side length of L11) is the area of the second terminal (electrode) 3 (for example, a square). The length of one side is wider than L12 (L11> L12)).

The substrate 51 is formed with a through hole 51a having a side length of L13 (L11> L13> L12) through which the second terminal (electrode) 3 can be passed and penetrating from the upper surface to the lower surface. The through hole 51a defines the accommodating portion 52 of the shunt resistor A. That is, when the shunt resistor A is inserted into the through hole 51a of the substrate 51 from the second terminal (electrode) 3 side, the second terminal (electrode) 3 and the resistor 5 are accommodated through the through hole 51a. It is housed in the part 52. In the shunt resistor A, since one side L11 of the first terminal (electrode) 1 is longer than one side L13 of the through hole 51a, the lower surface of the first terminal (electrode) 1 comes into contact with the upper surface of the substrate 51, so that the insertion operation is performed. Stops. As shown in FIG. 2, if the resistor 5 is accommodated substantially in the substrate 51 in the length direction thereof, the shunt resistor A can be accommodated substantially in the accommodating portion 52 of the substrate 51.

As shown in FIG. 3, a voltage signal extraction pattern 61 is built in the substrate 51. The voltage signal extraction pattern 61 is formed of a conductive material such as Cu, and is integrally molded with a substrate 51 formed of a resin or the like. In the example shown in FIG. 3, the voltage signal extraction pattern 61 has the following configuration.
1) Voltage detection signal extraction terminal 67 (first voltage detection terminal 67a, second voltage detection terminal 67b).
2) A first electrode surface 63 that is connected to the first voltage detection terminal 67a and is formed on the outer peripheral portion of the through hole 51a on the upper surface of the substrate 51.
3) A second electrode surface 65 connected to the second voltage detection terminal 67b and formed on the lower surface of the substrate 51 in a region excluding the through hole 51a.

The first electrode surface 63 has an opening 63a in which an electrode having substantially the same shape as the through hole 51a is not formed. The second electrode surface 65 has an opening 65a in which an electrode having substantially the same shape as the through hole 51a is not formed. Both electrode surfaces 63 and 65 are exposed from the substrate 51 surface.

With the above configuration, when the shunt resistor A is housed in the housing portion 52 in the substrate 51, the lower surface of the first terminal 1 comes into contact with the electrode surface 63.

A first bus bar 81 is provided on the upper portion of the shunt resistor A, and the upper surface of the first terminal 1 contacts the lower surface of the first bus bar 81. The first bus bar 81 is formed with a through hole 81a that penetrates the shaft portion 71a of the mounting screw 71. The first terminal 1 is formed with a 1a into which the shaft portion 71a of the mounting screw 71 is screwed. For example, the length L1 of the mounting screw 71 is the thickness of the first bus bar 81 and the first terminal 1.

A second bus bar 91 is provided at the lower part of the substrate 51, and the lower surface of the second terminal 3 comes into contact with the upper surface of the second bus bar 91. Further, the electrode surface 65 also contacts the upper surface of the second bus bar 91.

The first bus bar 81 and the shunt resistor A can be fixed by the mounting screw 71 (fixing means). In FIGS. 1 and 2, the length of the shaft portion 71a is L1, and only the first bus bar 81 and the first terminal 1 of the shunt resistor A can be fixed.

By adhering the lower surface of the first terminal 1 and the electrode surface 63 and the second terminal 3 and the upper surface of the second bus bar 91 with solder or a conductive adhesive, respectively, the first bus bar 81 to the second bus bar 81 to the second The mounting structure up to the bus bar 91 of the above can be fixed.

As described above, in the mounting structure of the shunt resistor according to the present embodiment, the resistance of the shunt resistor A is obtained by accommodating the shunt resistor A in the accommodating portion 52 defined by the through hole 51a in the substrate 51. The height (thickness) in the mounting structure of the thick portion of the body 5 can be lowered.

Therefore, the mounting structure of the shunt resistor can be miniaturized.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. FIG. 4 is an exploded perspective view showing a mounting structure of a shunt resistor according to a second embodiment of the present invention, and FIG. 5 is a side sectional view of the mounting structure (fixed structure).

The mounting structure of the shunt resistor according to the present embodiment is different from the mounting structure of the shunt resistor according to the first embodiment in the following points.
1) The second terminal 3 of the shunt resistor B according to the present embodiment is provided with a through hole 3a having a diameter larger than that of the first terminal 1. As a result, even if the length L2 of the shaft portion 71b of the mounting screw 71 is lengthened, it is possible to prevent the shaft portion 71b from coming into contact with the second terminal 3.
2) The second bus bar 91 is provided with a through hole 91a.
3) The shaft portion 71b of the mounting screw 71 has a length L2 that can be inserted into the through hole 91a of the second bus bar 91.

As described above, according to the mounting structure of the shunt resistor according to the present embodiment, the mounting structure is such that the first bus bar 81 to the second bus bar 91 are fixed by the fixing means using the mounting screws 71. it can.

By making the diameter of the through hole 81a formed in the first bus bar 81 larger than the outer diameter of the shaft portion 71a of the mounting screw 71, the mounting screw 71 does not come into contact with the first bus bar 81. By doing so, a long screw can be used as the mounting screw 71.

(Third Embodiment)
Next, a third embodiment of the present invention will be described. FIG. 6 is an exploded perspective view showing the mounting structure of the shunt resistor according to the third embodiment of the present invention, and FIG. 7 is a side sectional view of the mounting structure (fixed structure). FIG. 8 is a perspective view showing a configuration example of the substrate and the voltage signal extraction pattern built in the substrate according to the present embodiment.

The mounting structure of the shunt resistor according to the present embodiment is different from the mounting structure of the shunt resistor according to the first embodiment in the following points.
1) The shunt resistor C is provided with the first terminal 1, but unlike the first embodiment, the shunt resistor C is not provided with the second terminal before fixing. That is, no electrode is provided at the end of the resistor 5 on the mounting side.
2) The substrate 51 is provided with a plurality of through holes 51b through which each end of the resistor 5 of the shunt resistor C on the mounting side penetrates. For example, in FIG. 6, since the shunt resistor C has four columnar resistors 5, each of them is provided with four through holes 51b.
3) Further, as shown in FIG. 8, the voltage signal extraction pattern is different from the voltage signal extraction pattern of the first embodiment shown in FIG.

As shown in FIGS. 8A and 8B, even in this embodiment, the substrate 51 has a built-in voltage signal extraction pattern. The voltage signal extraction pattern 61 is formed of a conductive material such as Cu, and is integrally molded with a substrate 51 formed of a resin or the like. In the example shown in FIG. 8, the voltage signal extraction pattern 61 has a voltage detection signal extraction terminal 67 (first voltage detection terminal 67a, second voltage detection terminal 67b).

Unlike FIG. 3, in FIG. 8, the first voltage detection terminal 67a is not connected to the first electrode surface 63 formed on the outer peripheral portion of the through hole 51a on the upper surface of the substrate 51, but is shown in FIG. As shown in 8 (a), for example, it is drawn out from a contact 63b provided at a position exposed on the upper surface of the substrate 51 at a position between two through holes 51b.

By extracting the first voltage signal from the position between the two resistors 5, a stable voltage signal can be extracted.

When the shunt resistor C is mounted on the first electrode surface 63 formed on the upper surface of the substrate 51 outside the four through holes 51b, the first terminal 1 is in contact with the first electrode surface 63. It is electrically connected to both 63b.

On the other hand, it has a second electrode surface 65 that is connected to the second voltage detection terminal 67b and is formed on the lower surface of the substrate 51 in a region excluding a plurality of through holes 51ab (a region excluding the hole portion 65b).

The first electrode surface 63 has an opening 63a having substantially the same shape as the outer periphery of the resistor 5 and in which the electrode 65 is not formed. The second electrode surface 65 has a plurality of openings 65b in which electrodes having substantially the same shape as the plurality of resistors 5 are not formed. Both electrode surfaces 63 and 65 are exposed from the substrate 51 surface together with the contact 63b.

With the above configuration, when the shunt resistor C is housed in the housing portion 52 in the substrate 51, the lower surface of the first terminal 1 comes into contact with the electrode surface 63.

A first bus bar 81 is provided on the upper portion of the shunt resistor C, and the upper surface of the first terminal 1 contacts the lower surface of the first bus bar 81. A screw hole 1a into which the shaft portion 71a of the mounting screw 71 is screwed is formed in the first bus bar 81 and the first terminal 1 of the shunt resistor C.

A second bus bar 91 is provided at the lower part of the substrate 51, and the lower end surface of the resistor 5 comes into contact with the upper surface of the second bus bar 91.

The first bus bar 81 and the shunt resistor C can be fixed by the mounting screw 71 (fixing means). In FIGS. 6 and 7, the length of the shaft portion 71a may be such that only the first bus bar 81 and the first terminal 1 of the shunt resistor A can be fixed.

By adhering the lower surface of the first terminal 1, the electrode surface 63, the lower surface of the resistor 5, and the upper surface of the second bus bar 91, respectively, with solder or a conductive adhesive, the first bus bar 81 to the first It is possible to have a fixed mounting structure up to the bus bar 91 of 2. Further, in the present embodiment, since the second bus bar 91 also serves as the second terminal, it is not necessary to provide the second terminal, and the height can be further reduced accordingly.

As described above, in the mounting structure of the shunt resistor according to the present embodiment, by accommodating the shunt resistor C in the accommodating portion 52 in the substrate 51, the thick portion of the resistor 5 of the shunt resistor C is provided. The height (thickness) in the mounting structure can be reduced.
Therefore, the mounting structure of the shunt resistor can be miniaturized.

(Fourth Embodiment)
Next, a fourth embodiment of the present invention will be described. 9 and 10 are exploded perspective views showing a mounting structure of a shunt resistor according to a fourth embodiment of the present invention, FIG. 11 is a perspective view of the mounting structure viewed from below, and FIG. 12 is a mounting structure. It is a perspective view which saw the structure from diagonally above.

The mounting structure of the shunt resistor according to the present embodiment is different from the mounting structure of the shunt resistor according to the third embodiment in the following points.
1) In the shunt resistor D, the columnar resistor 5 is made of a resistor material which is connected to the resistor 5a made of a resistor material on the first terminal 1 side at the tip (bottom surface) of the resistor 5a. Also has a lower conductor 5b with a low resistivity. The lower conductor 5b is formed of, for example, a metal material such as Cu, and is connected to the tip (bottom surface) of the resistor 5a by brazing or the like.

As shown in FIG. 11, in the mounting structure, the lower conductor 5b is inserted into through holes (not shown) penetrating the resistors formed on the substrate 51 and the second bus bar 91, respectively. On the lower surface (back surface) of the second bus bar 91, it is fixed to the second bus bar 91 by a soldering portion 101a or the like.

The mounting screw 71 is the same as the third embodiment in that the first bus bar 81 and the first terminal 1 are fixed by screwing.

FIG. 12 is a diagram showing a configuration example of a current extraction unit according to the present embodiment. Compared with the configuration shown in FIG. 8, the configuration shown in FIG. 12 is formed with a through hole 91c through which the shaft portion 71a of the mounting screw 71 penetrates.

FIG. 13 is a cross-sectional view showing a mounting structure (fixed structure) of the shunt resistor D according to the present embodiment. FIG. 13A is a diagram showing a structure in which the tip of the resistor 5 is formed of a resistance material. FIG. 13B is a diagram showing a structure in which a conductive material is connected to the tip of the resistor 5.

In the structure shown in FIG. 13A, it is difficult for the current to flow in the resistor 5, and the current I1 flowing in the resistor 5 concentrates in the portion in contact with the soldering portion 101a (I2). Therefore, heat is generated locally, and the resistance value of the shunt resistor D tends to be unstable.

On the other hand, in the structure shown in FIG. 13B, since the lower conductor 5b made of a metal material such as Cu having a low resistivity is formed on the bottom surface of the resistor 5, the currents are evenly distributed as shown in the current I3. Easy to flow. Therefore, local heat generation is suppressed. In addition, it is possible to prevent the resistance value of the shunt resistor D from becoming unstable.

As described above, according to the present embodiment, the current flows uniformly in the lower part (bottom part) of the resistor. Therefore, the location where the current is concentrated can be reduced, and the problems of local heat generation and unstable resistance value can be prevented.

In the above-described embodiment, the configurations and the like shown in the drawings are not limited to these, and can be appropriately changed within the range in which the effects of the present invention are exhibited. In addition, it can be appropriately modified and implemented as long as it does not deviate from the scope of the object of the present invention. In addition, each component of the present invention can be arbitrarily selected, and an invention having the selected configuration is also included in the present invention.

The present invention can be used for mounting structures of shunt resistors.

A, B, C, D Shunt resistor 1 Terminal 1 (electrode)
3 2nd terminal (electrode)
51 Substrate 51a Through hole 52 Accommodating portion 63 First electrode surface 63a Opening 65 Second electrode surface 65a Second opening 61 Voltage signal extraction pattern 67 Voltage detection signal extraction terminal 67a First voltage detection terminal 67b Second Voltage detection terminal 71 Mounting screw 81 First bus bar 91 Second bus bar

Claims (7)

It is a mounting structure of a shunt resistor in which a shunt resistor is mounted on a board with a built-in pattern that incorporates a voltage signal extraction pattern.
It is defined by a through hole formed in the thickness direction of the pattern-embedded substrate, and is provided between the first terminal and the second terminal which are sequentially provided from the side opposite to the mounting side of the shunt resistor. A shunt is provided to accommodate at least a portion of the resistor,
Mounting structure of shunt resistor. The through hole defining the accommodating portion has a size that allows the insertion of the resistor.
A wiring current bar that also serves as the second terminal of the shunt resistor is arranged below the pattern-embedded substrate.
The mounting structure of the shunt resistor according to claim 1. A metal material having a resistivity lower than that of the resistor is connected to the second terminal side of the resistor.
The metal material and the wiring current bar are connected to each other.
The mounting structure of the shunt resistor according to claim 2. The through hole defining the accommodating portion has a size that allows the insertion of the second terminal.
The mounting structure of the shunt resistor according to claim 1. The second terminal is connected to the wiring current bar.
The mounting structure of the shunt resistor according to claim 3. A bus bar is arranged on the first terminal side of the shunt resistor.
A fixing means for fixing the bus bar and the first terminal is provided.
The mounting structure of the shunt resistor according to claim 2. The fixing means
Further, the pattern-embedded substrate and the wiring current bar are fixed.
The mounting structure of the shunt resistor according to claim 6.

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