JPH01265544A - Electronic device - Google Patents

Abstract

PURPOSE:To prevent the disconnection of wires, which is caused by the fluctuation of a filler, by a method wherein the movement of the filler is inhibited by inhibiting members provided on the rear of a cover and the displacement of the wires buried in the filler is made small. CONSTITUTION:Electronic components 1 are incorporated in a housing 4, in which terminals 3 are incorporated, the terminals 3 and the components 1 are connected to each other by wires 5 and after a gel-like filler 6 is poured in the housing 4, the housing 4 is sealed with a cover 7. At that time, inhibiting members 7a to inhibit the fluctuation of the filler 6 are provided on the side of the rear of the cover 7. Whereupon, a space, which is formed on the upper surface of the filler 6 in the housing 4, is partitioned by the members 7a provided on the rear of the cover 7 into narrow labyrinths including the wires 5. The fluctuation of the filler 6 is inhibited by the members 7a provided side by side to the wires 5 and becomes hardly transmittable to the arrangement places of other wires 5 adjacent to the members 7a. Thereby, the disconnection of the wires, which is caused by the fluctuation of the filler, is prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an electronic device using a gel-like filler.
In particular, it relates to the structure of electronic devices that are highly reliable in harsh operating environments, such as those mounted on automobiles and subjected to large vibrational accelerations.

[Conventional technology]

This type of device is described in Japanese Patent Application Laid-Open No. 59-208800. This device has a structure in which electronic components are built into a housing with embedded terminals, the electronic components and terminals are connected with wires, a gel-like filler is placed inside the housing, and the housing is sealed with a cover. There is. The electronic components are mounted on a base having a substantially uniform thickness. Connection with the housing is made around the base.

[Problems to be solved by the invention]

In conventional devices, no consideration was given to suppressing the vibrations of the filling material inside the housing against the vibrations received when the car is running.

When subjected to vibration, the filler vibrates with a large displacement amplitude, and the wires buried therein are repeatedly deformed.

On the other hand, resin materials that have the function of protecting electronic components from moisture, etc. are used as fillers, and fillers with various elastic modulus are used.6 If a material with a large elastic modulus is used, When the cycle is applied, the difference in thermal expansion between the filler material and the component causes a large force to be applied to the wire.
In addition, if a gel-like material with a small elastic modulus is used, the displacement amplitude of the filling material when subjected to vibration tends to increase.
The wire embedded in this filling material is also repeatedly displaced. As described above, the wire is prone to breakage due to thermal changes or mechanical displacement, especially when the vibration of the filler material is repeatedly applied from the side of the wire.

Wires are more likely to break due to fatigue.

Further, when attaching an electronic device to an object to be fixed such as an automobile body, if the mounting surface of the object to be fixed is not flat, the base may warp due to the tightening force of the screws.

When this warpage reaches the part where the electronic component is mounted, it acts on the electronic component and causes it to collapse.

Furthermore, in a harsh environment where an excitation force is applied, a separating force acts on the joint between the base and the housing, resulting in problems such as the joint between the base and the housing being destroyed after long-term use.

An object of the present invention is to provide an electronic device that can suppress vibration of a filler and prevent wire breakage.

Another object of the present invention is to provide an electronic device in which the housing is not peeled off from the base due to vibration.

Furthermore, another object is to provide an electronic device that can be assembled while observing interference between a wire and a suppressing member that suppresses vibration of a filler.

[Means to solve the problem]

In order to achieve the above object, the present invention incorporates an electronic component into a housing incorporating a terminal, connects the terminal and the component with a wire, and after filling the housing with a gel-like filler, The electronic device is sealed with a cover, and a suppressing member for suppressing vibration of the filler is provided on the back side of the cover.

In addition, a metal base is placed at the bottom of the housing,
The base is provided with a thick wall part and a thin wall part having a mounting hole on the outer periphery of the thick wall part, and an electronic component is mounted on the upper surface of the thick wall part, and the thick wall part is fitted and mounted inside the housing. It is what was done.

Furthermore, a frame body is interposed between the cover and the housing, and the frame body is provided with an opening for injecting the filler material to a size that allows the wire to be seen from the outside, and a deterrent is provided to suppress vibration of the filler material. The members are integrally molded, and the restraining member is interposed between the wires.

[Effect]

Since the space formed on the top surface of the filler in the housing is divided into a narrow labyrinth containing the wire by the restraining member on the back of the cover, the vibration of the filler is suppressed by the restraining member placed in parallel with the wire, and This makes it difficult for the force to be transmitted to other wire locations, and the force applied to the wire can be kept extremely small, thereby preventing wire breakage.

In addition, the base has a thick wall for the part where the electronic component is mounted, and a thin wall for the mounting part, so that even if there is a warp on the mounting surface of the object to be fixed to the electronic device, the thin part absorbs it and makes it relatively Warpage of the mounting surface is not transmitted to the thick wall part with high bending rigidity.
Destruction of electronic components can be prevented.

Since the thick portion of the base is fitted and bonded to the inside of the housing, compressive residual stress is generated on the bonded surface due to cooling during use of the electronic device.

As a result, it becomes extremely resistant to compression and difficult to peel off.

In addition, by providing a suppressing member for suppressing the vibration of the filler in the frame that has an opening through which the wire can be seen, separate from the cover, after the frame is bonded to the housing, the wires and filler can be injected, etc. You can easily check the status.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

After the electronic component 1 is mounted on the base 2 as shown in FIGS. 3 and 4, it is assembled inside the housing 4.
The base 2 and the housing 4 are integrated with an adhesive 8. A terminal 3 is embedded in the housing 4 in advance, and the terminal and the electronic component are connected with a wire 5. As shown in FIGS. 1 and 5, after the filler 6 is injected, the cover 7 is fixed to the upper opening of the housing with an adhesive 9, and the inside of the housing is sealed.

As shown in FIG. 6, the electronic component 1 includes a pellet 1a made of a semiconductor material such as Si, and an insulating plate 1d made of an insulating material such as A1□○ that insulates between the pellet 1a and the base. and a heat spreader-IC made of a metal material with good thermal conductivity such as Cu, which diffuses the heat generated in the pellet 1a and makes it easier to escape, and a heat spreader-IC that relieves stress due to the difference in thermal expansion coefficient between the pellet 1a and the heat spreader-10. Adjust the connection height of the wire 5 and the thermal expansion buffer plate 1b made of a metal material such as Mo, W, Fe-Ni, etc., which has a thermal expansion coefficient intermediate between the thermal expansion coefficients of the two. pad 1e, and these members are made of Pb.
-5n solder or the like.

Here, if a plate made of a material with a coefficient of thermal expansion close to that of the pellet 1a, electrical insulation, and high thermal conductivity and metallized is used, the insulation plate 1d, the heat spreader 1c, and the thermal expansion Instead of the three members of the buffer plate 1b, the component 1 can be formed by inserting these three members, and the structure can be simplified. This kind of materials include SiC, AI
An example is N.

To join the electronic component 1 and the base 2, a Pb-3n solder or an adhesive such as silicone rubber is used.

In addition to these parts, it is also possible to incorporate various parts such as IC packages and chip capacitors. As a method for assembling these parts, it is advantageous in terms of productivity to solder them onto the wiring board and then fix the wiring board onto the base 2 using a silicone rubber adhesive or the like.

FIG. 1 shows a longitudinal section through the device. The base 2 has a thin part 2a and a thick part 2b, a mounting hole 2c is formed in the thin part 2a, and an electronic component 1 is mounted in the thick part 2b. The device is fixed to a fixed object with a screw through this mounting hole 2c. Even if the surface of the fixed object is warped,
Since the thin wall portion 2a has low bending rigidity, it absorbs this warpage,
The electronic component 1 mounted on the thick wall portion 2b is not warped because the warpage is not transmitted to the thick wall portion 2b which has relatively high bending rigidity.
Since no force is applied to the electronic component 1, damage to the electronic component 1 can be prevented.

Base 2 makes it easier to dissipate the heat generated in one part.
It is made of materials with good heat conductivity such as A1 and Cu, which have good heat dissipation effects. On the other hand, the housing 4 is made of a resin material that is inexpensive. Generally, resin materials have a larger coefficient of thermal expansion than metal materials, and the housing is bonded to the base with an adhesive that hardens at high temperatures. In this case, as the housing contracts during the cooling process after bonding, large thermal stress is generated in the bonded portion, which may cause peeling. Therefore, compressive residual stress is generated on the bonding surface due to cooling after bonding. Therefore, the adhesive surface becomes very strong against compression and peeling can be prevented.

The thick part 2b of the base is provided with a protrusion 2d on the side surface of the base on which the electronic component 1 is attached, and an adhesive reservoir 11 is formed between the protrusion and the housing.
It has a structure in which the adhesive 8 is hardened. The adhesive 8 has a weak adhesive force with the metal base 2, but a strong adhesive force with the resin housing 4. Therefore, in this structure, even against the force of peeling the housing 4 upward, Projection 2d
This part acts to prevent this, making it a strong structure. In order to sufficiently spread the adhesive 8 into the adhesive reservoir 11, cutouts 2e and 2e' as shown in FIG. Inject adhesive 8 into the other notch 2e'.
After confirming that the adhesive has gone around, raise the temperature and apply adhesive 8.
It is effective to harden the It is possible to eliminate a portion under the protrusion 2d where the adhesive 8 does not go around.

If the notches 2e and 2e' are formed at symmetrical positions, an epoxy adhesive with strong adhesive force is suitable as the material for the adhesive 8.

The material for the wire 5 is Au, which does not easily cause corrosion.

Materials such as Al t N ip Cu can be used.

As the material for the filler 6, a resin material is used that has the function of protecting the electronic component 1 from moisture and the like. This kind of material has various elastic modulus, but in this example, by using a gel-like material with a very small elastic modulus, the wire 5 is prevented from breaking due to thermal cycles. ing. Silicone gel is an example of this type of material.

As shown in FIG. 2, a protrusion 7a is formed on the back surface of the cover 7 as a suppressing member for suppressing the vibration of the filler.When the cover 7 is attached to the housing 4, the protrusion 7a
immersed in the filling material 6, and a complicated labyrinth is formed between the filling material and the inner surface of the cover. Therefore, the filler material is restrained by the protrusion, and displacement of the filler material 6 due to vibration is suppressed, so that the displacement applied to the wire 5 is also reduced, and wire breakage can be prevented.

The filler 6 is injected into the housing 4 in a liquid state, and after applying the adhesive 9 on top of the housing 4.

Cover with cover 7. Thereafter, the temperature is raised to harden the filler 6 into a gel-like state, and at the same time harden the adhesive 9 and fix the cover 7. By such a method,
It becomes possible to sufficiently introduce the filler material 6 between the protrusions 7a, and the working process can be simplified.

When the cover is attached, the filler 6 pushed away by the protrusions 7a escapes to a portion where the protrusions 7a are not present.

If this further fills the space under the cover 7 which has expanded due to thermal expansion or the like, the internal pressure will increase and the adhesive material 9 of the cover 7 may peel off.

In order to prevent this, it is important to select an appropriate filling amount so that the unfilled portion 10 is sufficiently formed, as shown in FIG.

Furthermore, by attaching the cover 7 in an inert gas such as N2, it is possible to further reduce the risk of deterioration of the internal electronic components 1 due to oxidation or the like.

As the material for the cover 7, a resin material is preferable from the viewpoint of cost. In order to restrain vibrational displacement, a material with a high elastic modulus is suitable6.In addition, in order to suppress thermal stress, the same material as the housing 4 should be used, and a material with a coefficient of thermal expansion relatively similar to the metal material used for the base 2 should be used. It is better to use materials. Examples of materials that meet these requirements include polybutylene terephthalate, commonly known as PBT.

As a result of vibration analysis, it was found that the wire was weak against vibration in a direction perpendicular to the plane containing the wire (in the present example, in a horizontal direction parallel to the plane of the paper in FIG. 1). Therefore, it is effective to form the protrusions 7a at positions that sandwich both sides of the wire 5 so as to suppress the displacement of the filler 6 in this direction.

The wider the width of the protrusion 7a, the higher the rigidity of the protrusion 7a, which improves the restraining effect of the filler.

On the other hand, the narrower the gap between the protrusions 7a, the smaller the displacement of the filler 6.

In order to narrow the gap, positioning the wire 5 and the protrusion 7a is important. For this purpose, positioning of the cover 7 to which the protrusion 7a is fixed, the component 1 to which the wire 5 is fixed, and the housing 4 in which the terminal 3 is embedded also becomes a problem. The problem of positioning accuracy between each component can be solved by joining each component while being set on a jig having a positioning guide. It is preferable to use the mounting hole 2c of the base as a reference for positioning.

Even if such positioning is performed, problems such as variations in wire shape remain, so the gap between the protrusions 7a is
It is appropriate that the clearance between the protrusion 7a and the protrusion 7a be approximately 1 mm on average.

In order to reduce the gap between the protrusions 7a, it is better to use a structure in which each wire 5 is sandwiched between the protrusions 7a, but for areas where the distance between the wires is narrow, a structure in which multiple wires are sandwiched together is recommended. can also be considered.

A sufficient effect can be obtained by setting the length of the protrusion 7a to cover the range from one connection part of the wire 5 to the other connection part, as shown in FIG.

The height of the protrusion 7a is as follows with the cover 7 attached.
It needs to have a height that is at least above the point where the tip reaches the filler 6. The higher the protrusion 7a is and the smaller the gap between it and the upper surface of the component 1, the more effective the vibration suppression effect of the wire becomes. However, when the gap disappears due to dimensional changes due to thermal expansion and contraction, force is applied to the component 1, which may cause malfunction of the component 1 or force to peel off the adhesive 7.

To prevent this, a gap of about 0.5+u+ on average is appropriate.

The cover 7 having the protrusion 7a having such a shape can be made by casting.

Another embodiment of the present invention will be described with reference to FIGS. 7 to 9.

In this embodiment, a cover 7 and a protrusion 11 are used as shown in FIG.
is a separate part. The protruding body 14 is formed integrally with the frame body 12, as shown in FIG. This frame 12
An opening 13 is provided in the housing 4 so that the status of all the wires can be viewed from the outside when the wire is attached to the housing 4, and the filler is injected using this opening.

Therefore, after fixing the frame 12 to the housing 4 with the adhesive 13, the filler 6 can be injected and the cover 7 can be bonded with the adhesive 14.

According to this embodiment, before the cover 7 is attached, the frame 1
It is easy to check the filling state of the filler 6 through the opening 13 of 2, and to check the state of the internal wire 5 as shown in FIG.

Note that the suppressing member for suppressing the vibration of the filler is not limited to the projections and protrusions shown in the embodiments, but may be a protrusion, for example, as the protrusion.

Furthermore, the structure of the base and the joint structure between the base and the housing can be applied to applications other than electronic devices by providing a structure that suppresses vibration of the filler.

〔Effect of the invention〕

According to the present invention, the restraining member provided on the back surface of the cover suppresses the movement of the filler, thereby reducing the displacement of the wire embedded in the filler, so that when the electronic device is subjected to vibration, Also, wire breakage due to vibration can be prevented.

In addition, since the mounting part of the base is made thinner than the mounting part of the electronic components, the warpage of the mounting surface can be absorbed by the thin wall part and the effect is not exerted on the mounting part, thereby preventing the adhesive of the electronic components from peeling off. be able to.

Furthermore, since the adhesive material is provided between the thick wall side surface of the base and the housing, even if a force is applied to the housing to separate it in the direction opposite to the base due to the vibration of the electronic device, it can sufficiently withstand the force. High reliability is ensured.

Further, since the restraining member is integrally molded on the frame and the opening is provided, the condition of the wire and filler can be observed from the outside, so that it is possible to improve the small part size during manufacturing.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view showing an embodiment of the present invention, Fig. 2 is a perspective view of a part of the cover of the same embodiment, Fig. 3 is a plan view of the cover before it is attached and the filler is injected, and Fig. 4 is a cross-sectional view in the same state, FIG. 5 is a cross-sectional view in the completed state,
FIG. 6 is a perspective view showing details of the electronic component, FIG. 7 is a vertical sectional view showing another embodiment of the present invention, FIG. 8 is a perspective view of the frame of the same embodiment, and FIG. FIG. 3 is a plan view before the cover is attached in the figure. 1...Electronic component, 2...Base, 3...Terminal. 4... Housing, 5... Wire, 6 Filling material, 7
... Cover, 8 ... Adhesive material, 9 ... Adhesive material, 10
...Non-filling material, 11...Protrusion, 12...Frame. 13...Adhesive material, 14...Adhesive material.

Claims (1)

[Claims] 1. An electronic device in which an electronic component is installed in a housing that includes a terminal, the terminal and the component are connected with a wire, a gel filler is placed in the housing, and the housing is sealed with a cover. 2. The electronic device according to claim 1, further comprising a suppressing member for suppressing vibration of the filler on the back side of the cover. 2. The electronic device according to claim 1, wherein the restraining member is a projection that reaches the filler. 3. In claim 1, a metal base is arranged at the lower part of the housing, the base is provided with a thick part and a thin part having a mounting hole on the outer periphery of the thick part, and the upper surface of the thick part is provided with a thin part having a mounting hole. What is claimed is: 1. An electronic device in which an electronic component is mounted, and the thick portion is fitted and bonded to the inside of the housing. 4. The electronic device according to claim 3, wherein an adhesive reservoir is provided between a side surface of the thick portion of the base and an inner surface of the housing opposite to the side surface of the thick portion. 5. The electronic device according to claim 1, wherein the length of the restraining member is formed to be approximately equal to the distance between the connecting portions at both ends of the wire. 6. The electronic device according to claim 1, wherein the restraining members are arranged in parallel to sandwich the wire. 7. The electronic device according to claim 6, wherein the restraining member is arranged so that the wire receives vibrations of the filler from the side on a surface of the restraining member facing the wire. 8. In an electronic device in which an electronic component is assembled into a housing incorporating a terminal, the terminal and the component are connected with a wire, a gel-like filler is placed in the housing, and the housing is sealed with a cover. A frame is interposed between the wire and the wire, the frame is provided with an opening for injecting the filler of a size that allows the wire to be seen from the outside, and a suppressing member for suppressing vibration of the filler is integrally molded, An electronic device characterized in that the restraining member is interposed between wires. 9. The electronic device according to claim 1, wherein the restraining member is arranged for each of the plurality of wires.