JP2002271063A - Terminal heat dissipation structure - Google Patents

Abstract

(57) [Problem] To provide a terminal heat radiating structure capable of relaxing thermal stress and mechanical stress acting on a soldered portion and preventing occurrence of solder cracks. SOLUTION: In a heat radiation structure of a terminal 26 in which one end 26a side is freely connected to heat generating components 16 and 17 and the other end 26b side is soldered to a substrate 21 in an upright state, a wide flat portion is formed in a middle portion 26c of the terminal 26. 26d is formed by bending, while the heat blocking plate 30 is disposed at a position facing the substrate 21 with a predetermined clearance therebetween, and the flat portion 26d of the terminal 26 abuts on the terminal holding portion 35 provided on the heat blocking plate 30. I made it freely. Further, a resin plate cover 40 that covers the heat insulation plate 30 is provided at a predetermined clearance from the heat insulation plate 30, and a terminal holding portion 35 of the heat insulation plate 30 and a terminal holding portion 43 provided on the plate cover 40 are provided. This allows the flat portion 26d of the terminal 26 to be freely pinched.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a terminal heat radiating structure in which a terminal for a large current is mounted on a printed circuit board used in, for example, an electronic control unit (ECU) of an automobile by soldering.

[0002]

2. Description of the Related Art FIG.
There are the following. In this mounting structure, as shown in FIG. 20, a soldering portion 2 at the lower end of a straight terminal 1 is inserted into a connection hole 6 formed in a printed circuit board 5, and the soldering portion 2 of the terminal 1 is Is attached by soldering to a land portion 7 formed around the connection hole 6 on the lower surface of the substrate. A heating component 4 such as a fuse or a relay is detachably connected to the upper end 3 of the terminal 1. In FIG. 20, a soldering portion (solder fillet) is indicated by reference numeral 8.

[0003]

However, in the conventional mounting structure of the terminal 1 on the printed circuit board 5, the terminal 1
A heat-generating component 4 such as a fuse or a relay is fitted to the upper end 3 of the substrate 1, and a current is applied while the soldering portion 2 of the terminal 1 is soldered to the land 7 of the substrate 5. When the fitting portion between the heat-generating component 4 and the upper end 3 of the terminal 1 generates heat, the heat is directly transmitted to the soldering portion 8 via the terminal 1 as a large thermal stress (thermal stress). Solder cracks (solder cracks) are likely to occur, and when the heat-generating component 4 is attached to or detached from the upper end 3 of the terminal 1, a large mechanical stress is directly applied to the soldering portion 8 via the soldering portion 2 of the terminal 1. It was added from the direction, and solder cracks were easily generated in the soldered portion 8.

Accordingly, the present invention has been made to solve the above-mentioned problems, and it is possible to reduce thermal stress and mechanical stress acting on a soldered portion, and to reliably generate solder cracks. An object of the present invention is to provide a terminal heat dissipation structure that can be prevented.

[0005]

According to a first aspect of the present invention, there is provided a heat dissipating structure for a terminal in which one end is freely connected to a heat-generating component and the other end is soldered to a substrate in an upright state. While a wide flat portion is formed by bending, a heat blocking plate is disposed at a position facing the substrate with a predetermined clearance therebetween, and the flat portion of the terminal abuts on a terminal holding portion provided on the heat blocking plate. It is characterized by being made freely.

In this terminal heat radiating structure, heat generated by self-heating of a heat-generating component connected to one end of the terminal, which is transmitted to the other end of the terminal and a portion to be soldered to the substrate, is bent in the middle of the terminal. The heat is radiated from the wide flat portion to the terminal holding portion side of the heat shielding plate, and the heat radiation effect is improved. In addition, since the wide flat portion in the middle of the terminal is in contact with the terminal holding portion of the heat insulation plate arranged at a position facing the substrate with a predetermined clearance therebetween and is separated from the soldering portion, the soldering is performed. The thermal stress acting on the part is reduced. These prevent the occurrence of solder cracks in the soldered portion.

According to a second aspect of the present invention, there is provided the terminal heat radiating structure according to the first aspect, further comprising a resin plate cover which covers the heat insulating plate at a predetermined clearance from the heat insulating plate. The flat portion of the terminal can be freely held between the terminal pressing portion and the terminal pressing portion provided on the plate cover.

In this terminal heat radiating structure, the terminal flat portion of the terminal can be freely held between the terminal pressing portion of the heat insulating plate and the terminal pressing portion of the plate cover covering the heat insulating plate. The heat generated by the self-heating of the heat-generating component connected to one end of the terminal
The heat is efficiently radiated from the flat portions of the terminals to the respective terminal pressing portions of the heat shield plate and the plate cover, and the heat radiation effect is further improved. Also, since the flat part of the terminal is clamped and fixed between the terminal holding part of the heat insulation plate and the terminal holding part of the plate cover, the dynamics acting on the soldering part when attaching or detaching the heat-generating component to one end of the terminal. Stress is reduced. As a result, stresses such as thermal stress and mechanical stress acting on the soldered portion are alleviated, and the occurrence of solder cracks in the soldered portion is reliably prevented.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an exploded front view showing an electric junction box integrated with an electronic control unit according to an embodiment of the present invention, FIG. 2 is a front view of the electric junction box, and FIG. 3 is a plan view of the electric junction box. 4 is a plan view of an electronic control unit built in the electric junction box,
FIG. 5 is a front view of the electronic control unit, and FIG.
7 is a cross-sectional view taken along line AA in FIG. 4, FIG. 8 is an enlarged plan view of a portion E in FIG. 6, and FIG.
10 is a sectional view taken along line BB in FIG. 4, FIG. 11 is an enlarged plan view of a portion F in FIG. 6, and FIG. 12 is a sectional view taken along line JJ in FIG. FIG. 13 shows KK in FIG.
14 is an explanatory view of a land portion used in the electronic control unit, FIG. 15 is a perspective view showing a relationship between the land portion and terminals, FIG. 16 is an enlarged plan view of a portion G in FIG. 6,
17 is a sectional view taken along the line PP in FIG. 16, and FIG.
19 is a right side view of the electronic control unit.

As shown in FIGS. 1 to 3, the electronic control unit-integrated electric connection box 10 is made of a synthetic resin and has a box-shaped upper case 11 and is fitted to the upper case 11 so as to be able to be locked and detached. Box-shaped main cover 12 made of synthetic resin
A busbar layer 13 disposed on the upper surface side of the main cover 12 and an electronic control unit (ECU) 20 built in between the upper case 11 and the main cover 12 below the busbar layer 13. It is roughly configured. The electric connection box 10 is mainly used for, for example, power distribution of an automobile, and the electronic control unit 20 controls on / off of, for example, an engine, a light, a wiper, and the like of the automobile.

As shown in FIG. 1, the bus bar layer 13 has a plurality of bus bars 15 arranged on an insulating substrate 14, and one end of each bus bar layer 13 is bent upward to form a slit-shaped press-contact portion 15a or the like. ing. Each busbar 15
The pressure contact portions 15a extend to the relay mounting portion 12a and the fuse mounting portion 12b which are integrally formed on the upper surface side of the main cover 12 shown in FIG. The relay mounting portion 12a has a plug-in relay 16 as an electronic component.
However, a fuse 17 as an electronic component is mounted on the fuse mounting portion 12b.

As shown in FIGS. 1, 4, 5, 10, and 19, the electronic control unit 20 includes straight and crank-shaped terminals 25 and 26 and a resistor 27 as an electronic component.
And a main board (substrate) 21 made of a synthetic resin and mounted with a relay 28 and the like, respectively, and screws 39 so as to face the main board 21 via a plurality of cylindrical bosses 31 with a predetermined clearance therebetween. A substantially plate-shaped terminal plate (heat insulation plate) 30 made of synthetic resin and fixed to the lower surface side of the terminal plate 30 with a plurality of projections 41 such as a plurality of hooks fitted into the plurality of recesses 32 of the terminal plate 30. A plate-shaped plate cover 40 made of synthetic resin and disposed above and opposed to a part of the terminal plate 30 (excluding the area of the frame-shaped holding plate 33) with a predetermined clearance therebetween. Are stacked and held at a predetermined distance from the main board 21 via the holding plate 33 of the terminal plate 30;
And a plurality of control components 51 and 5 such as a microcomputer (CPU).
2 and the jumper wire 5
3 and a rectangular control board 50 connected via terminals (not shown).

As shown in FIG. 6 to FIG.
At the time of assembling with the terminal plate 30, the soldering portion 25 a at the lower end of the straight rod-shaped terminal 25 is guided by the terminal plate 30 into the connection hole 21 a of the main board 21. That is, when assembling the main board 21 and the terminal plate 30, the connection of the main board 21 hole 21
a and a terminal plate 3 holding the intermediate portion 25b of the terminal 25
0, the positions of the positioning holes 34a coincide with each other.
Of the terminal 25 in the connection hole 21a of the main board 21 at a position facing the main board 21 with a predetermined clearance therebetween.
5a is guided and inserted.

The soldering portion 25a of the terminal 25 inserted into the connection hole 21a of the main board 21 is
5 is soldered to a land 22 formed on the lower surface of the main board 21 in a state where the main board 5 is vertically erected.
1 is maintained. This soldered portion (solder fillet) is indicated by the symbol H.

Further, a projecting portion (locking portion) 25c locked in the positioning hole 34a of the terminal plate 30 is formed integrally with the intermediate portion 25b of the terminal 25 so as to protrude annularly. Further, the positioning holes 34 of the terminal plate 30
A is provided in two rows at the center of the terminal press-fitting portion 34 projecting in a block shape on the upper surface side of the terminal plate 30. The terminal press-fit portion 34 protrudes upward from the opening 42 of the plate cover 40, and the terminal press-fit portion 34
The upper end 25d of the more exposed terminal 25 is the main cover 12
Of the connector mounting portion 12c. This terminal 2
5 has an external connector 18 as an electric component
Are fitted.

The projection 25c of the terminal 25 is locked at a predetermined position in the positioning hole 34a of the terminal plate 30 by press-fitting, and this locking state is not sufficiently separated even by mechanical stress due to attachment and detachment of the external connector 18. It has become.

As shown in FIGS. 4 and 10 to 13, the large current terminal 26, which is cranked in an L-shape and is wide as a whole, has an upper end (one end) side formed as a pressure contact portion 26a having a slit blade shape. Heating components such as a plug-in relay 16 and a fuse 17 and an external connector 18 are freely connectable. A pair of forked soldering portions 26b, 26b on the lower end (the other end) side of the terminal 26 are vertically inserted into the connection holes 21b of the main board 21 so as to be inserted into the lower surface of the main board 21. The main board 21 is held by soldering to the formed land portion 23. This soldered portion (solder fillet) is indicated by the symbol H.

As shown in FIG. 11, a wide flat portion 26d is formed in the middle portion 26c of the terminal 26 so as to be parallel to the main substrate 21. The flat portion 26d is The terminal plate 30 can be freely contacted with the terminal pressing portion 35 of the terminal plate 30 disposed at a position facing the terminal plate 21 with a predetermined clearance therebetween. Terminal 2
The wide flat portion 26d of 6 is capable of abutting on a terminal pressing portion 43 provided on a resin plate cover 40 covering the terminal plate 30 with a predetermined clearance from the terminal plate 30. That is, the terminal holding portions 35 of the terminal plate 30 and the terminal holding portions 4 of the plate cover 40 are provided.
3, the wide flat portion 26d of the terminal 26 is clamped.

The terminal plate 30 and the plate cover 4
In the vicinity of the terminal holding portions 35 and 43, the terminal insertion holes 3 are provided.
6, 44 are formed respectively. The press contact portion 26a of the terminal 26 exposed from the terminal insertion hole 44 of the plate cover 40 projects to the relay mounting portion 12a, the fuse mounting portion 12b, the connector mounting portion 12c and the like of the main cover 12. Further, as shown by oblique lines in FIG. 11, the terminal pressing portion 43 of the plate cover 40 is formed to have a width substantially the same as that of the wide flat portion 26d of the terminal 26. FIG.
As shown in FIG. 5, the terminal holding portion 35 of the terminal plate 30 is also formed wide similarly.

Further, as shown in FIGS. 13 and 15, the soldered portions 26b, 26b at the lower end of the terminal 26 which is cranked in an L-shape are divided into two and subdivided. Further, a pair of soldering portions 26 of the terminals 26 of the main board 21 are provided.
b, 26b, a pair of connection holes 21b, 2
1b are formed. Further, FIGS.
As shown in FIG. 5, a pair of round terminal insertion holes 23a, 23a are formed at positions of the terminals 26 of the land portion 23 facing the pair of soldering portions 26b, 26b, respectively. A pair of constrictions 23b, 2 around the land 23 between the pair of terminal insertion holes 23a, 23a of the land 23.
3b is formed.

As shown in FIGS. 6, 10, 16, and 17, at a predetermined position of the terminal plate 30, a component accommodating portion 37 for accommodating and holding the resistor (heating component) 27 is formed in a concave shape. . The concave component housing portion 37 and the main board 2
1 has a pair of insertion holes 37 for inserting a pair of lead portions 27b, 27b protruding from the component body 27a of the resistor 27.
a, 37a and 21c, 21c are formed respectively.

The lead 27b of the resistor 27 is inserted into each of the concave component housing 37 and each of the insertion holes 37a and 21c of the main board 21 so that the resistance 27 is inserted into the bottom 37b of the concave component housing 37. Each of the lead portions 27b and the land portion 24 formed on the lower surface side of the main board 21 are held by soldering in a state where the component main body 27a is separated. This soldered portion (solder fillet) is indicated by the symbol H. In addition, the component housing 37 of the plate cover 40
An opening 45 having the same shape as the size of the component accommodating portion 37 is formed at a position opposed to.

As shown in FIG. 5 to FIG. 7, FIG. 18, and FIG. 19, heat generating components such as a resistor 27 and a relay 28 are mounted via a frame-shaped holding plate 33 integrally formed on the right side of the terminal plate 30. The main board 21 and the control board 50 on which the control components 51 and 52 such as a microcomputer (CPU) are mounted are held and laminated at a predetermined distance. That is, on the ceiling side of the holding plate 33, a heat blocking plate 38 is provided with a pair of side wall portions 33 of the holding plate 33.
a, 33a are integrally formed at the upper end. This heat shield plate 3
An air layer S is formed between the heat shield plate 38 and the control board 50 via a plurality of convex portions 38a integrally formed on the upper surface of the substrate 8.

The control board 50 is formed integrally with each of the pair of side walls 33a, 33a of the holding plate 33 and the heat shield plate 38, and has a hook-like shape which is engaged with the plurality of recesses 54 of the control board 50. It is positioned via each hook 33b. The air layer S between the heat insulating plate 38 and the control board 50 is always maintained at a constant value via the convex portion 38a of the heat insulating plate 38.

According to the electronic control unit-integrated electric connection box 10 of the above embodiment, as shown in FIG.
A wide flat portion 26d is formed by bending in the middle portion 26c, and a terminal plate 30 is arranged at a position facing the main substrate 21 with a predetermined clearance therebetween.
The flat portion 26d of the terminal 26 can freely contact the terminal holding portion 35 provided on the terminal plate 30, so that the engine heat transmitted to the soldering portion H between the soldering portion 26b of the terminal 26 and the land portion 23 of the main board 21 can be used. Including surrounding environmental heat and terminals 2
6 and the relay 16 and the fuse 1 connected to the pressure contact portion 26a
7 can be radiated to the terminal holding portion 35 of the terminal plate 30 via the flat portion 26d of the terminal 26, and the heat radiation effect can be improved. Thus, the thermal stress acting on the soldered portion H can be reduced, and the occurrence of solder cracks in the soldered portion H can be prevented.

In particular, the terminal holding portion 3 of the terminal plate 30
5 and the terminal pressing portion 43 of the plate cover 40 covering the terminal plate 30, the flat portion 26d of the terminal 26 can be sandwiched freely. The heat generated by the self-heating of the fuse 17 is transferred to the terminal plate 30 as a heat insulating plate made of synthetic resin through the wide flat portion 26d of the terminal 26.
And heat can be efficiently radiated to the respective terminal pressing portions 35 and 43 of the plate cover 40 made of synthetic resin.
The heat radiation effect of the heat-generating components such as the relay 16 and the fuse 17 can be further improved.

Further, since the flat portion 26d of the terminal 26 is freely pinched and fixed by the terminal pressing portion 35 of the terminal plate 30 and the terminal pressing portion 43 of the plate cover 40, the terminal 2
When attaching / detaching the relay 16 or the fuse 17 to / from the press-contact portion 26a of the terminal 6, the soldered portion 26b of the terminal 26 and the main board 2
The mechanical stress acting on the soldered portion H with the one land portion 23 can be reliably reduced. Further, a sufficient distance (play) from the flat portion 26d, which is a fixing point of the terminal 26 sandwiched between the terminal pressing portion 35 of the terminal plate 30 and the pressing portion 43 of the plate cover 40, to the soldered portion H is ensured. Therefore, the thermal stress acting on the soldered portion H can be reliably reduced. Accordingly, stresses such as thermal stress and mechanical stress acting on the soldering portion H can be more reliably alleviated within the limited space (height direction) of the electronic control unit 20, and the soldering portion H The generation of solder cracks can be more reliably prevented.

According to the above-described embodiment, the electronic control unit-integrated electric connection box incorporating the electronic control unit has been described. However, the electronic connection unit separate from the electric connection box and the electric connection unit not incorporating the electronic control unit are described. Needless to say, the embodiment can be applied to a box or the like.

[0030]

As described above, according to the first aspect of the present invention, a wide flat portion is formed in the middle of the terminal by bending, and the heat insulating plate is provided at a position facing the substrate with a predetermined clearance therebetween. Since the flat part of the terminal was able to abut on the terminal holding part provided on the heat insulation plate,
Heat generated by the self-heating of the heat-generating component connected to the other end of the terminal and one end of the terminal that is transmitted to the soldered part of the board is transferred to the terminal block of the heat insulation plate via a wide flat part in the middle of the terminal. The heat can be dissipated to the side, and the heat dissipating effect can be further improved. Further, since the wide flat portion in the middle of the terminal is in contact with the terminal holding portion of the heat insulation plate and is separated from the soldered portion, the thermal stress acting on the soldered portion can be reduced. Thus, it is possible to prevent the occurrence of solder cracks in the soldered portion.

According to the second aspect of the present invention, the flat portion of the terminal can be freely pinched by the terminal pressing portion provided on the heat insulating plate and the terminal pressing portion provided on the plate cover covering the heat insulating plate. The heat generated by the self-heating of the heat-generating component connected to one end of the terminal, which is transmitted to the other end of the terminal and the soldered portion of the board, is connected to the terminal block of the heat shield plate and the plate cover through the flat portion of the terminal. The heat can be efficiently radiated to the respective sides, and the heat radiating effect can be further improved. In addition, the wide flat part in the middle of the terminal is pinched and fixed freely by the terminal holding part of the heat insulation plate and the terminal holding part of the plate cover. The mechanical stress acting on the attachment portion can be reduced. Accordingly, stresses such as thermal stress and mechanical stress acting on the soldered portion can be reduced, and the occurrence of solder cracks in the soldered portion can be reliably prevented.

[Brief description of the drawings]

FIG. 1 is an exploded front view showing an electric control box integrated with an electronic control unit according to an embodiment of the present invention.

FIG. 2 is a front view of the electric junction box.

FIG. 3 is a plan view of the electric junction box.

FIG. 4 is a plan view of an electronic control unit built in the electric connection box.

FIG. 5 is a front view of the electronic control unit.

FIG. 6 is a sectional view taken along line DD in FIG. 5;

FIG. 7 is a sectional view taken along line AA in FIG.

FIG. 8 is an enlarged plan view of a portion E in FIG. 6;

FIG. 9 is a sectional view taken along line HH in FIG. 8;

FIG. 10 is a sectional view taken along the line BB in FIG. 4;

FIG. 11 is an enlarged plan view of a portion F in FIG. 6;

FIG. 12 is a sectional view taken along the line JJ in FIG. 11;

13 is a sectional view taken along the line KK in FIG.

FIG. 14 is an explanatory diagram of a land used in the electronic control unit.

FIG. 15 is a perspective view showing a relationship between the land and the terminal.

FIG. 16 is an enlarged plan view of a portion G in FIG. 6;

FIG. 17 is a sectional view taken along the line PP in FIG. 16;

FIG. 18 is a sectional view taken along line CC in FIG. 4;

19 is a right side view of the electronic control unit.

FIG. 20 is a cross-sectional view showing a state of soldering a terminal and a board in a conventional example.

[Explanation of symbols]

 Reference Signs List 16 relay (heating component) 17 fuse (heating component) 21 main board (board) 26 terminal 26a press-contact portion (one end) 26b soldering portion (other end) 26c midway 26d flat portion 30 terminal plate (heat blocking plate) 35 terminal Holding part 40 Plate cover 43 Terminal holding part

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yayoi Maki 206-1 Nunobikihara, Haibara-cho, Haibara-gun, Shizuoka Prefecture F-term (reference) in Yazaki Parts Co., Ltd. 5E322 AA11 AB11 CA05 5G361 BA01 BB01 BB02 BC01 BC02

Claims (2)

[Claims] 1. A heat dissipating structure for a terminal having one end side freely connectable to a heat-generating component and the other end side soldered to a substrate in an upright state, wherein a wide flat portion is bent and formed in an intermediate portion of the terminal. A heat-dissipating plate, wherein a heat-insulating plate is disposed at a position facing the substrate with a predetermined clearance therebetween, and a flat portion of the terminal is made free to abut on a terminal pressing portion provided on the heat-insulating plate. Construction. 2. The terminal heat radiating structure according to claim 1, further comprising: a resin plate cover that covers the heat insulation plate at a predetermined clearance from the heat insulation plate. A terminal heat radiating structure, wherein a flat portion of the terminal is freely held by a terminal pressing portion provided on a plate cover.