JPH11307301A - Assembly structure for shunt resistance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce parts cost and assembling cost, and to maintain reliability of measured values. SOLUTION: An electronic component unit 1 is constituted of a print circuit board 2 on which each kind of electronic component is loaded, and a shunt resistance 3 mounted on the print circuit board 2, and cover case 4 covering the print circuit board 2. A through-hole 23, into which a terminal part 32a of the shunt resistance 3 is fit in, is formed on the print circuit board 2, and the shunt resistance 3 bent into a U-shape is mounted on the cover case 4, and the cover case 4 is mounted on the print circuit board 2. In this case, the mounting position of the shunt resistance 3 is set so that each terminal part can be fitted into the corresponding through-hole 23.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an assembly structure of a shunt resistor used mainly for detecting current in an electronic component unit for a vehicle.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 5, an assembly structure of a shunt resistor applied to an electronic component unit for a vehicle has been known. As shown in this figure, an electronic component unit 100 includes a printed circuit board 101 on which electronic components are mounted.
And a shunt resistor 102 for current detection mounted on the printed board 101 and a lid case 103 covering the printed board 101 on which the shunt resistor 102 is mounted.

The shunt resistor 102 is formed in a belt shape by using a current-carrying material having a predetermined resistance value, and is formed in an M-shape by bending a central portion and both side portions. At both ends of the shunt resistor 102, a pair of locking claws 104 projecting in the width direction are provided, and a terminal 105 is formed at a portion on the tip side of the locking claw 104. 101 is the terminal 105
Are formed.

[0004] Each terminal 105 is connected to the through hole 10.
The shunt resistor 102 is mounted on the printed circuit board 101 by being soldered while being inserted into the printed circuit board 101. After mounting the shunt resistor 102, the lid case 103 is put on the printed circuit board 101, and the electronic component unit 100 is completed.

[0005]

By the way, in the conventional mounting structure of the shunt resistor 102 as described above,
In order to stabilize the mounting state of the shunt resistor 102 by the urging force, the shunt resistor 102 is formed of a spring material,
In order to prevent the tip of the shunt resistor 102 from excessively penetrating the through hole 106, it is necessary to provide a locking claw 104, which has the problem of increasing the material cost.

The shunt resistor 102 is fixed to the printed circuit board 101 only at both ends and the center portion is suspended in the air. There is a problem that the reliability of a measured value using the shunt resistor 102 is reduced because the shunt resistor 102 becomes unstable and sometimes comes off.

Further, in order to make the current capacity of the shunt resistor 102 predetermined, a large length may be required. In this case, the shunt resistor 102 is
For example, as in the example shown in FIG. 5, it is necessary to perform a troublesome work of bending into an M shape and mounting each end to the through hole 106, and accordingly, the mounting efficiency is reduced and the shunt resistor 102 is used. Printed circuit board 101
There is a problem in that the occupied area increases, and the electronic component unit 100 cannot be made compact.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and it is possible to maintain the reliability of measured values while reducing the cost of parts and assembly. It is an object of the present invention to provide a simple shunt resistor mounting structure.

[0009]

According to a first aspect of the present invention, there is provided a shunt resistor mounting structure, wherein the shunt resistor is mounted on an electronic component unit for current detection. Consists of a printed circuit board on which various electronic components are mounted, a shunt resistor mounted on the printed circuit board, and a lid case covering the printed circuit board. Both ends of the shunt resistor are fitted into the printed circuit board. While the through hole that is made is drilled,
A shunt resistor bent in a U-shape is attached to the lid case, and the shunt resistor is mounted on the printed circuit board such that each end is fitted into the corresponding through hole. The mounting position is set.

According to this shunt resistor mounting structure,
By placing the lid case on the printed board, both ends of the shunt resistor attached to the lid case are fitted into the through holes of the printed board, whereby the shunt resistor is mounted on the printed board. In this way, it is possible to mount the shunt resistor on the printed circuit board by one operation of putting the lid case on the printed circuit board, and the two-operation method of mounting the shunt resistor on the printed circuit board and then covering the lid case as in the conventional case The workability of assembling is improved as compared with.

Further, by attaching the shunt resistor to the lid case, the area occupied by the shunt resistor on the printed circuit board is reduced, so that the space secured on the printed circuit board can be effectively used.

Further, since the shunt resistor is fixed to the printed circuit board at both ends and is held by the lid case, the mounted state is very stable and does not come off due to vibration of the vehicle or the like.

According to a second aspect of the present invention, there is provided the shunt resistor mounting structure according to the first aspect, wherein each of the ends of the shunt resistor is fitted into the corresponding through hole. It is characterized in that it is soldered in a state of being held.

According to this shunt resistor mounting structure,
The connection between the shunt resistor and the printed wiring on the printed circuit board is stabilized.

According to a third aspect of the present invention, there is provided the shunt resistor assembling structure according to the first or second aspect, wherein the lid case has a recessed surface on the front side. And a mounting hole communicating with the inside of the lid case formed at both ends of the fitting groove.

According to this shunt resistor mounting structure,
The shunt resistor is supported by the lid case in a locked state in which the shunt resistor is press-fitted into the fitting groove, and therefore does not fall out of the through hole due to vibration, temperature change, or the like. Also,
Since part of the shunt resistor is exposed to the outside of the lid case, it is possible to release the heat generated during energization to the outside, and suppress the temperature rise in the space covered by the lid case on the printed circuit board. Becomes possible.

[0017]

FIG. 1 is an exploded perspective view showing an embodiment of an assembly structure of a shunt resistor according to the present invention.
FIG. 2 is an assembled perspective view. 3 is a sectional view taken along line AA of FIG. 2, and FIG. 4 is a sectional view taken along line BB of FIG. As shown in these figures, an electronic component unit 1 to which a shunt resistor is applied includes a rectangular printed board 2 on which various electronic components are mounted, a rod-shaped shunt resistor 3 mounted on the printed board 2, and And a box-shaped lid case 4 with the shunt resistor 3 mounted thereon, which is open at the bottom and covers the printed circuit board.

On the surface of the printed circuit board 2, various electronic components 21 such as resistors and capacitors, which are connected and fixed to predetermined portions of a printed wiring (not shown), are mounted. Is provided with a connection connector 22 with the connection surface facing outward. A pair of through holes 23 in the width direction for inserting the shunt resistor 3 is provided at an appropriate position on the printed circuit board 2.

The shunt resistor 3 is made of a conductive material having a predetermined resistance value and a predetermined length, and is formed by bending both sides of the shunt resistor 3 downward at right angles. It comprises a pair of vertical portions 32 in the width direction extending downward from both sides of the portion 31. At the lower end of each vertical part 32, a terminal part 32a connected to the printed circuit board 2 is set.

The lid case 4 is formed in a rectangular shape slightly larger than the printed board 2 in a plan view, and has a square groove 41 into which a peripheral portion of the printed board 2 is fitted in an inner wall surface at a lower end thereof. A notch window 42 having a lower opening corresponding to the shape of the connector 22 is provided in a portion corresponding to the connector 22, and the cover case 4 is covered with the printed circuit board 2 so that the square groove 41 is formed as shown in FIG. The connector 22 fits into the cutout window 42 while being fitted onto the periphery of the printed circuit board 2 in a press-fit state.

The top plate 43 of the lid case 4 is provided with a fitting groove 44 crosswise in the width direction at a position corresponding to a straight line connecting the pair of through holes 23 of the printed circuit board 2. At a position facing each through hole 23 of the fitting groove 44, a mounting hole 45 for inserting the vertical portion 32 of the shunt resistor 3 is formed. These mounting holes 45
The shunt resistor 3 is attached to the lid case 4 in a state in which the vertical portions 32 are fitted into the root portions of the shunt resistors 3 so that the horizontal portions 31 are fitted in the fitting grooves 44.

As shown in FIGS. 3 and 4, a plurality of pairs of locking projections 46 facing each other are bulged on the groove wall of the fitting groove 44, and the horizontal portion 31 of the shunt resistor 3 is fitted. The horizontal portion 31 enters these lower portions while elastically deforming the plural pairs of locking projections 46 by press-fitting into the fitting grooves 44, and the horizontal portion 31 enters the fitting grooves 44 by restoring the elastically deformed locking projections 46. On the other hand, it is in a state where it is prevented from falling off.

The length of the shunt resistor 3 is set to be substantially the same as the height of the lid case 4, so that the lid case 4 with the shunt resistor 3 mounted thereon is covered with the printed circuit board 2 and the square groove 41 is formed. Is pressed into the peripheral portion of the printed circuit board 2 so that the terminal portion 32 a of the shunt resistor 3 is fitted into the through hole 23. Then, in a state where each of the terminal portions 32a is fitted in the corresponding through hole 23, for example, by performing a soldering process by a flow solder method, the molten solder flows into the through hole 23, and the terminal portion 32a and the printed wiring are formed. Is connected (at this time, the connection of the terminal of another electronic component and the printed wiring is also performed), whereby the assembling process of the electronic component unit 1 is completed.

As described in detail above, the mounting structure of the shunt resistor 3 according to the present invention includes the electronic component unit 1, a printed board 2 on which various electronic components are mounted, and a shunt mounted on the printed board 2. The printed circuit board 2 is formed with a through hole 23 into which the terminal portion 32a of the shunt resistor 3 is fitted. The mounting position of the shunt resistor 3 is set so that the shunt resistor 3 bent in a letter shape is attached, and the lid case 4 is attached to the printed circuit board 2 so that each end is fitted into the corresponding through hole 23. It is. Therefore, by covering the printed circuit board 2 with the cover case 4, the terminal portions 32 a of the shunt resistor 3 attached to the cover case 4 fit into the through holes 23 of the printed circuit board 2, thereby connecting the shunt resistor 3 to the printed circuit board 2. 2 can be set.

As described above, the lid case 4 is attached to the printed circuit board 2.
The shunt resistor 3 can be mounted on the printed circuit board 2 by one operation of placing the shunt resistor 3 on the printed circuit board 2 as compared with the conventional two-operation method of mounting the shunt resistor 3 on the printed circuit board 2 and then covering the lid case 4. The workability of assembling can be improved.

Further, by mounting the shunt resistor 3 on the lid case 4 along the inner wall surface, the area occupied by the shunt resistor 3 on the printed board 2 is reduced, and the space on the printed board 2 secured by this is reduced. Can be used effectively.

The cover case 4 has a fitting groove 44 formed on the front surface side for press-fitting the shunt resistor 3 and a cover case 4 formed at both ends of the fitting groove 44. Since the communication hole 45 is provided, the shunt resistor 3
Since it is supported by the lid case 4 in a state of being press-fitted into the fitting groove 44, it is possible to reliably prevent the through-hole 23 from coming off due to vibration, temperature change, or the like. Also,
Since a part of the shunt resistor 3 is exposed to the outside of the lid case 4, it is possible to release heat generated during energization to the outside. The rise can be suppressed.

The shunt resistor 3 and the printed wiring are connected to the through holes 23 corresponding to the terminal portions 32a.
The connection between the shunt resistor 3 and the printed wiring on the printed circuit board 2 can be strengthened by soldering in a state where the shunt resistor 3 is inserted into the printed circuit board 2.

The present invention is not limited to the above embodiment, but includes the following contents.

(1) In the above embodiment, the shunt resistor 3 is mounted on the cover case 4 by press-fitting the horizontal portion 31 into a fitting groove 44 formed in the cover case 4.
However, the present invention is not limited to attaching the shunt resistor 3 to the lid case 4 by such an assembling operation.
The shunt resistor 3 is attached to the lid case 4 by mounting the shunt resistor 3 in a mold in advance at the time of manufacturing the lid case 4 by injection molding, and then injecting a molten synthetic resin into the cavity by a so-called integral molding method. You may.

(2) In the above embodiment, the vertical portion 32 of the shunt resistor 3 has the mounting hole 45 of the lid case 4.
The horizontal portion 31 is press-fitted into a fitting groove 44 recessed on the surface side of the top plate 43 of the lid case 4 so that the terminal portion 32a of the shunt resistor 3 is inserted into the through hole of the printed circuit board 2. 23, but instead of this, a fitting groove is formed in the back side of the top plate 43 of the lid case 4, and the horizontal portion 31 of the shunt resistor 3 is pressed into the fitting groove. You may.

[0032]

According to the shunt resistor assembling structure of the first aspect of the present invention, the electronic component unit includes a printed board on which various electronic components are mounted, and a shunt resistor mounted on the printed board. And a cover case that covers the printed circuit board. The printed circuit board has a through hole into which both ends of the shunt resistor are fitted, while the cover case has a shunt resistor bent in a U-shape. The mounting position of the shunt resistor is set so that each end is fitted into the corresponding through hole by mounting the lid case on the printed circuit board, so that the lid case is mounted on the printed circuit board Both ends of the shunt resistor fit into the through holes of the printed circuit board, and the shunt resistor is attached to the printed circuit board. It can be in the state.

As described above, the shunt resistor can be mounted on the printed circuit board by one operation of mounting the cover case on the printed circuit board. The conventional shunt resistor is mounted on the printed circuit board and then the cover case is mounted. The workability of assembling the resistance can be improved as compared with the two-operation method.

By mounting the shunt resistor on the lid case, the area occupied by the shunt resistor on the printed circuit board is reduced, and the space secured on the printed circuit board can be effectively used.

Further, since the shunt resistor is fixed to the printed circuit board at both ends and is held by the lid case, the mounting state is very stable, and the shunt resistor can be securely removed from the printed circuit board due to vehicle vibration or the like. Can be prevented.

According to the shunt resistor assembling structure of the second aspect of the present invention, the shunt resistor is soldered in a state where each end is fitted in the corresponding through hole, so that the shunt resistor and the shunt resistor are connected to each other. The connection state with the printed wiring on the printed board can be strengthened.

According to the shunt resistor assembling structure of the third aspect of the present invention, the cover case has a fitting groove for press-fitting the shunt resistor concavely formed on the surface side, and both ends of the fitting groove. The shunt resistor is supported by the lid case in a locked state press-fitted into the fitting groove because of the provision of a mounting hole communicating with the inside of the lid case drilled in the Can be reliably prevented from coming off. In addition, since part of the shunt resistor is exposed to the outside of the lid case, it is possible to release heat generated during energization to the outside, and to reduce the temperature rise in the space covered by the lid case on the printed circuit board. Can be suppressed.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing an embodiment of a shunt resistor mounting structure according to the present invention.

FIG. 2 is an assembled perspective view of an assembly structure of the shunt resistor of FIG. 1;

FIG. 3 is a sectional view taken along line AA of FIG. 2;

FIG. 4 is a sectional view taken along line BB of FIG. 2;

FIG. 5 is an exploded perspective view illustrating a conventional shunt resistor mounting structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electronic component unit 2 Printed circuit board 21 Electronic component 22 Connector 23 Through hole 3 Shunt resistance 31 Horizontal part 32 Vertical part 32a Terminal part 4 Lid case 41 Square groove 42 Notch window 43 Top plate 44 Fitting groove 45 Mounting hole

Claims (3)

[Claims] 1. An assembling structure of a shunt resistor mounted on an electronic component unit for current detection, wherein the electronic component unit is mounted on a printed circuit board on which various electronic components are mounted and mounted on the printed circuit board. Shunt resistor and a cover case that covers the printed circuit board. The printed circuit board has a through hole into which both ends of the shunt resistor are fitted, while the cover case has a U-shape. A shunt resistor bent in a shape is attached, and the attachment position of the shunt resistor is set such that each end is fitted into the corresponding through hole by mounting the lid case on the printed circuit board. A shunt resistor mounting structure characterized by the following. 2. The shunt resistor assembling structure according to claim 1, wherein said shunt resistor is soldered with each end fitted into the corresponding through hole. 3. The cover case has a fitting groove formed on the front surface side for press-fitting the shunt resistor, and mounting holes formed at both ends of the fitting groove and communicating with the inside of the cover case. The assembly structure of a shunt resistor according to claim 1, wherein the shunt resistor is provided.