JP2002319780A - Attaching structure of power transistor of electronic control unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent permeation of foreign matter like cuttings into a part between a power transistor and a heat sink, without using a jig when the power transistor is bolted on a heat sink, in an attaching structure of the power transistor of an electronic control unit wherein a case main body formed of resin is bonded on the heat sink on which the power transistor is fixed. SOLUTION: An elastic member 40 is stretched from a part of the case main body 12 formed of resin, and the power transistor 14 is energized (pressed) and bolted on the heat sink 16. In the elastic member, a notched part is formed on a position in the vicinity of the case main body. The elastic member is formed of metal, and its base end side is embedded in the case main body formed of resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power transistor mounting structure for an electronic control unit.

[0002]

2. Description of the Related Art Conventionally, in an electronic control unit or the like, a power transistor is attached to a heat sink via a bolt, and is housed in a resin case body. As an example, Japanese Patent Publication No. Hei 6-52831 or JP-A-169
284 publication.

When a power transistor is mounted on a heat sink, if foreign matter such as cutting chips enter the space between the power transistor and the heat transistor, heat generated from the power transistor is not efficiently dissipated by the heat sink. He held it up and bolted it.

[0004]

However, in recent years,
Due to the demand for miniaturization of the electronic control unit and an increase in the degree of integration of the electronic control unit, the work area is reduced, and such jigs cannot be used when the power transistor is mounted on the heat sink.

Accordingly, the present invention provides an electronic control unit in which a power transistor can be freely mounted on a heat sink without using a jig, preventing foreign matter such as cutting chips from entering the heat sink. An object of the present invention is to provide a power transistor mounting structure.

[0006]

In order to solve the above problems, according to the first aspect of the present invention, a resin case main body, a heat sink fixed in the resin case main body, and a heat sink mounted on the heat sink. In the power transistor mounting structure of the electronic control unit including at least a power transistor mounted via a bolt, an elastic body is extended from the resin case body, and the power transistor is urged onto the heat sink by the elastic body. It was configured to be attachable via the bolt while (pressing).

[0007] The elastic body is extended from the resin case body, and is brought into contact with a heat-generating component such as a power transistor, so that the power transistor can be attached via a bolt while being urged (pressed) onto the heat sink. Therefore, it is possible to prevent foreign matter such as cutting chips from entering between the power transistor and the heat sink without using a jig.

According to a second aspect of the present invention, the elastic body is formed to have a tapered shape toward the distal end when viewed from above.

Since the elastic body is formed so as to be tapered toward the distal end when viewed from above, the urging force at the distal end can be increased, and the power transistor can be securely fixed on the heat sink. .

According to a third aspect of the present invention, the elastic body is made of resin, and a cutout is provided at a position near the resin case body.

Since the elastic body is made of resin and the notch is formed at a position near the case body, more specifically, at a position near the base end of the elastic body, In addition to this, it is possible to easily perform the operation when removing the elastic body after bolting the power transistor to the heat sink.

That is, when the electronic control unit described above is mounted on a place where there is a lot of vibration such as a vehicle, consideration is given to the fact that the elastic body is detached from the case body due to the vibration and moves inside the unit to affect peripheral components. When the power transistor is to be removed after installation, the removal operation can be facilitated.

According to a fourth aspect of the present invention, the elastic body is made of metal, and a base end thereof is embedded in the resin case body.

Since the elastic body extending from the resin case body is made of metal and the base end thereof is buried in the resin case body, the same effect as described above can be obtained and the elastic body can be obtained. Does not need to be considered.

[0015]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of an electronic control unit according to an embodiment of the present invention. The electronic control unit according to this embodiment is mounted in an engine room of a vehicle (not shown), more specifically, on a room wall or an intake pipe of the engine.

FIG. 1 is a top view for explaining a mounting structure of a power transistor of an electronic control unit (hereinafter, referred to as a “unit”) 10 according to one embodiment of the present invention, and FIG. 2 is a unit 10 shown in FIG. FIG. 3 is a bottom view of the case main body 12 as viewed from below, and FIG.
It is a line sectional view.

The unit 10 has a case body (resin case body) 12 whose upper and lower ends are opened, and a heat sink (metal base) 16 fixed to the inside of the case body 12.
And the power transistor 14 mounted on the heat sink 16 via bolts 68, and mounted in the engine room of the vehicle (not shown) as described above.

The heat sink 16 is made of a metal material having high heat dissipation such as aluminum, and the upper part thereof is the case body 1.
2 is bonded to the lower end 12a. In addition, unit 10
Is a cover 1 made of a resin material and formed such that a peripheral edge (described later) is housed and adhered to a groove 12c formed over the entire periphery of the upper end 12b of the case body 12.
8 (not shown in FIG. 1).

The case body 12 is molded from a resin material such as PBT (polybutylene terephthalate) and has a collar formed of a substantially cylindrical metal material having a bolt insertion hole 20 near the center of two opposite sides thereof. 22 is
The resin is molded integrally with the case body 12.

The outer peripheral surface of the collar 22 that comes into contact with the case body 12 is subjected to appropriate knurling or the like to prevent the collar 22 from slipping out of the case body 12 and to prevent idling in the case body 12. The lower end 22 a and the upper end 22 b of the collar 22 are connected to the lower end 12
The resin is molded so as to protrude an appropriate amount from a, for example, about 0.2 to 0.5 mm.

The upper end 12b of the case body 12 is formed substantially flat, and a power transistor accommodating portion (described later) capable of accommodating the power transistor 14 is formed inside the lower end 12a.

As shown in FIG. 2, the lower end 12a of the case body 12 has a substantially groove-shaped recess 2 around its entire circumference.
4 are provided. As shown in FIG. 3, the heat sink 16 is provided with a convex portion 26 formed substantially in a rib shape over the entire circumference so as to correspond thereto. An outer wall portion 12d formed in a skirt shape is provided around the lower end 12a of the case main body 12 in order to prevent intrusion of fats, oils, water droplets, dusts, etc. and to enhance the reliability of bonding.

Four heat sink mounting portions 28 are formed at appropriate positions on the lower end 12a of the case body 12. In addition, the heat sink mounting part 28 has the collar 22 at its height.
Is formed so as to protrude from the lower end 12a of the case main body 12 by the same amount as the protruding amount (0.2 to 0.5 mm). This is because the heat sink 16 is
In order to prevent the heat sink 16 from partially moving up and down and being unable to be assembled with high accuracy due to the collar 22 projecting from two places being used as a fulcrum when being assembled, it is provided to prevent this. It is.

In the unit 10, the elastic body 40 is extended from the case body 12, and the elastic body 40
The power transistor 14 is configured to be attachable via a bolt 68 while urging (pressing) the power transistor 14 onto a heat sink (metal base) 16.

That is, as shown in FIG. 1, in this embodiment, a part of the unit 10 is extended to form an elastic body 40 similarly made of a resin material. Heat sink 1 by the tip 40a of
6 is biased.

As shown in the drawing, the elastic body 40 is formed in a tapered shape toward the distal end in a top view. That is, the elastic body 40
Is configured such that the diameter thereof is gradually reduced toward the distal end in a top view, and the biasing force is increased so that the power transistor 14 is firmly pressed onto the heat sink 16.

The base of the elastic body 40 in the vicinity of the case body is formed to have an appropriate curvature (arc).
Thereby, it is configured such that stress is not concentrated on a specific portion of the base end portion. As shown in FIG. 3, the elastic body 40 has a substantially inverted L-shape when viewed from the side, and is formed as a part of the case main body 12 during resin molding.

When the dimensional tolerance of the power transistor 14 and the heat sink 16 is relatively large, the elastic portion 40
The length or the urging force (elastic force) of the device is appropriately designed to absorb the dimensional tolerance.

The case body 12 has a connector connecting portion 50
Are integrally molded with resin. Connector connection part 5
0 is open at one end to form a connector connection port 52;
A terminal 5 for connecting a connector (shown by imaginary lines) 54 to a printed circuit board (described later) housed in the unit 10
6 is molded integrally with the case body 12 so as to protrude inward from the connector connection port 52.

A ventilation hole 58 is formed at the deepest portion of the connector connection port 52, and the inside of the unit 10 communicates with the outside. Protrusions 60 for locking the connector 54 are provided at appropriate positions on the wall surface of the connector connection portion 50, and an appropriate locking mechanism (not shown) provided on the connector 54 side.
As a result, the connector 54 is detachably connected to the connector connection unit 50.

The heat sink 16 will be described in further detail. As shown in FIG. 3, the heat sink 16 is formed in a substantially flat plate shape. A power transistor fixing portion 62 having a shape is formed.

The power transistor fixing part 62 has four bolt insertion holes 66 (1) at positions corresponding to the power transistor fixing holes 64 formed in the power transistor 14.
Are shown), and the bolt 68 is inserted into the bolt insertion hole 6.
6, a total of four power transistors 14 are attached.

A printed circuit board 70 on which various electronic components are mounted is accommodated in the unit 10. The lead 14 of the power transistor 14 is provided on the printed board 70.
b is connected. Further, a harness (not shown) is locked to the printed circuit board 70 via a connector 54, and is electrically connected to a control device (not shown) disposed outside to transmit and receive signals.

Next, the positional relationship between the power transistor accommodating portion 74 and other components will be described with reference to FIGS.

FIG. 4 is a partially enlarged perspective view showing a relative positional relationship with the components such as the printed circuit board 70 when the power transistor 14 is housed in the case main body 12. In the case body 12, the power transistor 14
At the position where is mounted, four power transistor accommodating portions 74 of substantially the same size are formed.

The power transistor accommodating portion 74 is formed substantially in a bathtub shape toward the heat sink 16 of the case body 12. The power transistor contact surface 76 that forms a part of the wall surface of the power transistor housing 74 is formed of a semicircular cutout and a rectangular cutout, and includes a communication portion 78 that communicates vertically between the case body 12. Communication part 76
Is used to pass the bolt 60 and a tool (driver) (not shown) when bolting the power transistor 14 to the heat sink 16.

A part of the power transistor contact surface 76 is formed in a stepped shape, and three lead insertion holes 80 into which the leads 14b of the power transistor 14 can be inserted are formed in each power transistor housing 74. Case body 1
2 is a board fixing portion 12 on which the printed board 72 can be placed.
e (shown in FIGS. 1, 3, and 4) is formed.

The main body 14a of the power transistor 14 is connected to the power transistor accommodating portion 74 by the lead insertion hole 80.
When it is accommodated in the power transistor 14, a lead 14 b extending from the power transistor 14 is formed at a position where it is inserted.

As described above, above the communicating portion 78, the elastic body 40 is formed so as to extend from the case body 12, and the power transistor 14 is connected to the heat sink 16
It is configured to bias upward.

Further, a second lead insertion hole 90 communicating with the lead insertion hole 80 is formed in the printed circuit board 70.
The second lead insertion hole 90 is configured to insert the lead 14b. Guide ribs 84 are formed at appropriate locations on the inner wall 82 (shown in FIGS. 1 and 3) of the case body 12 to guide the printed circuit board 70.

That is, the lead insertion hole (second lead insertion hole) 90 formed in the substrate 70 is
When the printed circuit board 70 is guided by the guide ribs 84 and fixed on the substrate fixing portion 12e, the lead 14b
Is formed at a position (indicated by a dashed line A) where the lead insertion hole 80 and the second lead insertion hole 90 are to be inserted.

In other words, the lead 14 b protruding from the case body 12 is inserted through both the lead insertion hole 80 formed in the power transistor housing 74 and the second lead insertion hole 90 formed in the printed circuit board 70. You will be guided as follows. Therefore, the lead 14b and the lead insertion hole 8
Positioning with 0 and 90 becomes easy.

Hereinafter, referring to FIG.
Will be described.

First, the power transistor 14 is housed in the case main body 12, and then an adhesive (not shown) is applied (injected) to an appropriate position of the lower end 12 a of the case main body 12, specifically, the entire circumference in the concave portion 24. You. As the adhesive to be used, a silicon-based adhesive that can absorb expansion and contraction is selected.

Next, (the lower end surface 12a of) the case body 12 is assembled on the heat sink 16. Specifically, the protrusion 26 provided on the heat sink 16 is fitted so as to be inserted into the recess 24 formed on the case body 12.

Next, bolts (not shown) for temporarily assembling the unit are inserted into the bolt insertion holes 20 of the collar 22 and the bolt insertion holes of the heat sink 16 (not shown), and the collar 22 (ie, using a nut (not shown)) is used. , Case body 1
2) and the heat sink 16 are fastened together. In this state, the periphery of the bonded position is heated and the adhesive is cured, whereby the bonding between the case body 12 and the heat sink 16 is completed.

Next, the bolt 68 is connected to the power transistor fixing hole 64 or the bolt fixing hole 24 through the communication portion 78.
(Not shown in FIG. 4).
4 is bolted onto heat sink 16.

At the time of bolting, since the power transistor 14 is urged on the heat sink 16 by the elastic body 40, the bottom surface of the main body 14a of the power transistor 14 is brought into close contact with the upper surface of the power transistor fixing portion 62. Therefore, the bottom surface of the power transistor 14 (the body 14a of the power transistor) and the heat sink 16 (more specifically, the power transistor fixing portion 6 of the heat sink)
No foreign matter such as swarf enters the upper surface of 2), and the use of a jig is no longer necessary.

After the case body 12 is fixed (bolted) on the heat sink 16, the printed circuit board 70 is inserted from an opening formed on the upper end 12 b side of the case body 12. The inserted printed board 70 is lowered along the guide ribs 84, and is pressed from above by an appropriate method and pushed in, and pushes and spreads a board fixing means 86 (shown in FIG. 1) formed in a hook shape in side view. It is lowered until it comes into contact with the substrate fixing portion 12e. Printed circuit board 7
0 contacts the substrate fixing part 12e, the substrate fixing means 86
Returns to its original shape, so that the printed circuit board 70 is fixed.

Next, the leads 14b and the printed circuit board 70
Are connected by a process such as soldering, and a cover 18 (shown in FIG. 3) is attached from above. The peripheral edge 92 of the end of the cover 18 is formed so as to hang down as shown in the figure, and the hung portion is accommodated in a groove 12 c formed over the entire circumference of the upper end 12 b of the case body 12.

Next, the accommodated end peripheral edge 92 and the groove 1
The silicone adhesive 94 is applied (injected) to the remaining portion (gap) of 2c, the cover 18 is pressed from above by a weight (not shown) or the like, and the periphery is heated to cure the adhesive 94. The bonding is completed.

The assembled unit 10 is fixed to an appropriate place in the engine room of the vehicle via a fixing bolt 100,
For example, it is integrally fixed to the unit mounting portion 102 (shown in FIG. 3) made of a metal member directly or via a stay on a room inner wall surface or an engine intake pipe,
The connector 54 is connected.

Next, the mounting structure of the power transistor of the electronic control unit according to the second embodiment of the present invention will be described.

FIG. 5 is a partially enlarged top view of a characteristic portion of the unit 10 according to the second embodiment of the present invention, specifically, a partially enlarged elastic body 140 viewed from above. The unit 10 according to the second to fourth embodiments does not differ from the first embodiment except for the configuration of the elastic body 140. Therefore, only the periphery is shown in an enlarged scale, and Configurations other than the body 140 will be described with the same reference numerals.

The above-described elastic body 40 according to the first embodiment is integrally formed of the same material as the case body 12, specifically, resin, and urges the power transistor 14 onto the heat sink 16. It is configured as follows. That is, the distal end 40a of the elastic body 40 according to the first embodiment is always urged upward from the power transistor 14, and when the unit 10 is mounted in a place where there is a lot of vibration, the elastic body 40 becomes a case. It may be detached from a position near the main body and move within the unit 10 to affect peripheral components.

In consideration of the inconvenience, the elastic body 140 according to the second embodiment has a cutout 142 near the case body.

That is, the elastic body 14 near the case body 12
0 at least one portion (specifically, the elastic body 1
The cutout portions 142 (two portions for each 40) are formed.

The formation of the notch 142 facilitates the removal of the elastic body 140. That is, in the step of assembling the unit 10, when the bolting of the power transistor 14 is completed,
0 can be easily removed from the case main body 12 by a manual operation or the like as shown by an imaginary line in FIG.

In the second embodiment, the power transistor 14 is mounted on the heat sink 16 without using a jig when bolting, because it is configured as described above.
Can be fixed, foreign matters such as cutting chips can be prevented from entering between the heat sink 16 and the elastic body 140 can be easily removed if necessary after bolting. it can.

Next, the mounting structure of the power transistor of the electronic control unit according to the third embodiment of the present invention will be described.

FIG. 6 is a partially enlarged side view of a characteristic portion of the unit 10 according to the third embodiment of the present invention, specifically, a partially enlarged elastic body 240 viewed from the side. Note that the elastic body 240 in the unit 10 according to the third embodiment is the same as the elastic body 14 according to the second embodiment.
The purpose is to obtain the same effect as 0.

The structure of the elastic body 240 will be specifically described. Although not shown, the elastic body 240 has substantially the same shape as the elastic body 40 according to the first embodiment when viewed from above. Also,
In a side view, as shown in FIG. 6, a cutout portion 242 is formed at a base end position of the elastic body 240 near the case main body 12 at a lower surface thereof, that is, at an appropriate position on the power transistor 14 side. .

The function and effect of the provision of the notch 242 are the same as those of the elastic member 14 according to the second embodiment.
Since it is not different from 0, the description is omitted.

In the third embodiment, the elastic member 240 can be easily removed if necessary, as in the case of the elastic member 140 according to the second embodiment, because of the configuration described above. Thereby, the same effect as in the second embodiment can be obtained.

Next, the mounting structure of the power transistor of the electronic control unit according to the fourth embodiment of the present invention will be described.

FIG. 7 is a partially enlarged side view of a characteristic portion of the unit 10 according to the fourth embodiment of the present invention, specifically, a partially enlarged elastic body 340 viewed from the side.

In the unit 10 according to the fourth embodiment, the elastic body 340 is made of metal and is configured to be integrally molded with the case main body 12 as shown in FIG. The elastic body 340 is fixed to the fixing hole 34 by an appropriate holding member (not shown) when the case body 12 is formed.
After holding at the position 2 and performing resin molding, the holding member is removed to obtain the configuration shown in the figure.

Although not shown, the elastic body 340 has substantially the same shape as the elastic bodies 40, 140, and 240 according to the first to third embodiments when viewed from above. Also,
When viewed from the side, the power transistor 1 extends in the left-right direction by an appropriate distance from the base end, and the power transistor 1
4 and is biased in contact with the power transistor 14 at its tip 340a.

In the fourth embodiment, since the configuration is as described above, the same operation as the configuration according to the first to third embodiments can be obtained, while the second and third embodiments are performed. It is not necessary to remove the elastic members 140 and 240 described above.

As described above, in the embodiment of the present invention, the resin case body (case body) 12, the heat sink (metal base) 16 fixed in the resin case body, and the heat sink In the power transistor mounting structure of the electronic control unit including at least the power transistor mounted via the bolt 68, the elastic body (40, 140, 240, 340) is extended from the resin case main body and the elastic body is extended. Thus, the power transistor can be attached via the bolt while biasing the power transistor on the heat sink.

Further, the elastic body is formed so as to have a tapered shape (FIG. 1) toward the distal end when viewed from above.

Further, the elastic body is made of resin,
At the position near the resin case main body, a notch (14
2, 242).

Further, the elastic body is made of metal,
The base end was buried in the resin case body (FIG. 7).

In this embodiment, the power transistor 14 and the power transistor housing 74 housed in the unit 10 and the elastic bodies 40, 140, 24
Although the number of 0 and 340 is four each, the number is not limited thereto and may be another appropriate number.

The elastic members 40, 140, 240, 34
The shape of 0 is not limited to the shape shown in the figure, but may be any shape as long as the above-described effects are obtained.

Although the heat sink 16 is made of a metal material made of aluminum, another metal material may be selected as long as it has high heat dissipation.

[0077]

According to the first aspect of the present invention, the elastic body is extended from the resin case body, and is brought into contact with a heat-generating component such as a power transistor. Since it is configured to be freely attachable, it is possible to prevent foreign matter such as cutting powder from entering between the power transistor and the heat sink without using a jig.

According to the second aspect of the present invention, since the elastic body is formed in a tapered shape toward the front end side in a top view, the urging force at the front end can be increased, and the power transistor can be mounted on the heat sink. It can be fixed securely.

According to the third aspect of the present invention, the elastic body is made of resin and the notch is formed at a position near the case body, so that the same effect as described above can be obtained. When the power transistor is bolted to the heat sink and the elastic body is to be removed, the operation can be facilitated.

That is, when the electronic control unit described above is mounted on a place where there is a lot of vibration such as a vehicle, consideration is given to the fact that the elastic body detaches from the case body due to the vibration and moves inside the unit to affect surrounding parts. When the power transistor is to be removed after installation, the removal operation can be facilitated.

Further, in the present invention, the elastic body extended from the resin case body is made of metal, and the base end side of the elastic body is embedded in the resin case body. In addition to the same effect as described above, there is no need to consider the detachment of the elastic body.

[Brief description of the drawings]

FIG. 1 is a top view for explaining a mounting structure of a power transistor of an electronic control unit according to one embodiment of the present invention.

FIG. 2 is a bottom view of a case main body 12 constituting the electronic control unit 10 shown in FIG. 1 as viewed from below.

FIG. 3 is a sectional view taken along line III-III in FIG. 1;

FIG. 4 is a partially enlarged perspective view showing a relative positional relationship with components such as a printed circuit board 70 when the power transistor 14 is housed in the case main body 12 in the electronic control unit 10 shown in FIG.

FIG. 5 is a partial enlarged top view of a characteristic portion of the power transistor mounting structure of the electronic control unit according to the second embodiment of the present invention, specifically, a partially enlarged elastic body 140 viewed from above. FIG.

FIG. 6 is a partial enlarged view of a characteristic portion of the power transistor mounting structure of the electronic control unit according to the third embodiment of the present invention, specifically, a partially enlarged elastic body 240 viewed from the side. It is a side view.

FIG. 7 is a partially enlarged view of a characteristic portion of a power transistor mounting structure of an electronic control unit according to a fourth embodiment of the present invention, specifically, a partially enlarged elastic body 340 viewed from the side. It is a side view.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 electronic control unit (unit) 12 case body (resin case body) 14 power transistor 16 heat sink (metal base) 18 cover 40, 140, 240, 340 elastic body 40 a (elastic body) tip 62 power transistor fixing part 68 Bolts 142, 242, notch 342, fixing part

Claims (4)

[Claims] 1. A power transistor mounting structure for an electronic control unit comprising at least a resin case body, a heat sink fixed in the resin case body, and a power transistor mounted on the heat sink via bolts. A power transistor of an electronic control unit, wherein an elastic body is extended from the resin case main body, and the power transistor is freely attached via the bolt while urging the power transistor on the heat sink with the elastic body. Mounting structure. 2. The elastic body according to claim 1, wherein the elastic body is formed in a tapered shape toward a distal end in a top view.
The mounting structure of the power transistor of the electronic control unit according to the paragraph. 3. The power transistor of an electronic control unit according to claim 1, wherein the elastic body is made of a resin, and a notch is provided at a position near the resin case body. Mounting structure. 4. The power transistor of an electronic control unit according to claim 1, wherein said elastic body is made of metal and a base end thereof is buried in said resin case body. Mounting structure.