JPH06296089A - Electric equipment - Google Patents

Abstract

PURPOSE:To enable an electric device, which is composed of an electric component and a case wherein the component is housed and held by filler and forcibly cooled down or heated up, to be protected against such troubles that the case is cracked at heating or cooling (thermal expansion, thermal shrinkage), or a signal wire connected between electric components in the case is disconnected. CONSTITUTION:Components 2 and 3 are housed in a case 1 and held by a mixture 8 of fragment 5 of the same material as that of the case 1 and filler 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric device in which electric parts are housed in a case via a holding member, and more particularly,
The present invention relates to an electric device in which a case is heated or cooled for sterilization or the like.

[0002]

2. Description of the Related Art FIG. 3 shows a conventional electric device of this type.
In FIG. 3, 1 is a case made of plastic, for example. In this case 1, electric parts of an electric device, for example, electric parts of an ultrasonic diagnostic probe, here, a flexible circuit 2 and a flexible circuit 3 are housed. The required portions (signal line portions) of the flexible circuit 2 and the flexible circuit 3 are connected by, for example, soldering.

In addition, these flexible circuits 2,
The gap between the case 3 and the case 1 is filled with a filling material 4 such as a silicone resin, an epoxy resin, or a polyurethane, so that they are insulated from each other and positioned within the case 1.

[0004]

As described above, electric parts (flexible circuits 2, 3 etc.) are housed in the case 1.
There is a case where the electric device is heated or cooled depending on the purpose of use in an electric device that is almost sealed via the filler 4 or is housed so that the filler 4 is not discharged to the outside of the case 1.

However, in the above-mentioned conventional apparatus, when the filler 4 having a coefficient of thermal expansion greatly different from the coefficient of thermal expansion of the outer case 1 is used, an unreasonable force is applied at a high temperature or a low temperature. When the degree is large, a gap may be formed at the boundary with the case 1 or the case 1 may be broken. In addition, the signal line arranged in the case 1 may be broken.

This will be described in detail below. That is, most substances have the property of becoming large when heated, and the degree thereof has a unique value (coefficient of thermal expansion) for each substance. When the value of the coefficient of thermal expansion of the filling material 4 is much larger than the value of the coefficient of thermal expansion of Case 1, a force corresponding to the value of the coefficient of thermal expansion is generated during heating as shown by arrows 6a and 6b. In this case, the arrow 6a
Represents the amount of thermal expansion of the filler 4 and the arrow 6b represents the amount of thermal expansion of the case 1, and a force corresponding to the difference between the arrows 6a and 6b is applied to the case 1, and due to this force. Case 1 was sometimes broken.

Further, at the time of heating, a force having a magnitude as shown by arrows 7a and 7b is also generated in the signal line soldering portion between the flexible circuit 2 and the flexible circuit 3.
That is, when heated, the flexible circuit 2 is filled with the filling material 4.
If the force (arrow 7a) received from the flexible circuit 3 is much larger than the force (arrow 7b) that the flexible circuit 3 receives from the filling material 4, the difference between these forces separates the two flexible circuits 2 and 3 (in the horizontal direction in the figure). Shearing force), which may cause disconnection of the signal line between the flexible circuits 2 and 3.

The above is the case of heating, but also in the case of cooling, the direction of force (arrows 6a, 6b; 7a, 7b).
The same as above can be said only with the opposite direction.

To solve such a problem, conventionally, a filler 4 having a coefficient of thermal expansion as close as possible to the coefficient of thermal expansion of the outer case 1 has been searched for from many fillers.
However, even if the coefficient of thermal expansion is satisfied, other conditions such as electrical, chemical and mechanical conditions, especially the electrical components (flexible circuits 2, 3 etc.) that can be put into the case 1 Often the conditions were not met and it was not possible to deal effectively.

The object of the present invention is to alleviate the excessive force generated during heating and cooling (thermal expansion and thermal contraction) without searching for a filler having a coefficient of thermal expansion close to that of the case. An object of the present invention is to provide an electric device that can prevent cracking of the case and disconnection of signal lines between electric components in the case.

[0011]

SUMMARY OF THE INVENTION The above object is to provide an electric device in which an electric component is housed in a case through a holding member, wherein the holding member includes a fragment of a substance of the same material as the case and a filler. This is achieved by using a mixture.

[0012]

The above mixture is composed of the fragments of the same material as the case and the filler, and the difference in the coefficient of thermal expansion between the case and the case is smaller than that of the filler in the conventional apparatus. When focusing only on the filler, the absolute amount of the filler decreases and the absolute amount of thermal expansion decreases.

The mixture holds electric parts in the case instead of the filler in the conventional apparatus, and has the same function as the filler in the conventional apparatus. However, this mixture has a smaller difference in the value of the coefficient of thermal expansion from that of the case as described above than the filler in the conventional apparatus, and therefore, even if the filler having a value close to the value of the coefficient of thermal expansion of the case is not searched for, the mixture is heated Unreasonable force generated during cooling (thermal expansion, thermal contraction) is mitigated, and cracking of the case and disconnection of signal lines between electric parts in the case are prevented.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below with reference to the drawings, but prior to the description of the specific embodiments, the principle thereof will be described first. That is, in an electric device in which electric parts are held and housed in a case with a filling material, the relationship between forces generated between the case and the filling material during heating and cooling (thermal expansion and contraction) and between the electric parts in the case is It is not simple because it depends on the material of the case and the filler, the material and size of the electric parts in the case, and the position where they are arranged. However, since the filler is used for reinforcement or penetrates into narrow gaps, and generally has a large volume ratio to the case, it has no influence on problems such as cracking of the case and disconnection of signal lines between electric parts in the case. large. Therefore, it is considered that controlling the thermal expansion of the filler has a great effect on the problems such as cracking and disconnection of the case.

Further, in an electric device exposed only to heating,
It is considered that the coefficient of thermal expansion of the filler should be equal to or slightly smaller than the coefficient of thermal expansion of the case. (The above is the case of heating, but in the case of cooling, it can be said that the same as the above except that the direction of the force is reversed.) Therefore, in the present invention, various characteristics conventionally used. It was considered to reduce the amount without changing the material of the filling material that satisfies the above condition. That is, the electric components in the case are held by a mixture (mixture) in which a crushed piece of the same material as the outer case material, for example, a chip of the raw material if the outer case is plastic is mixed with the filler. The mixture increases the portion where the coefficient of thermal expansion is exactly the same as the value of the coefficient of thermal expansion of the case, and reduces the proportion of problematic filling such as case cracking and disconnection.

According to this, the value of the coefficient of thermal expansion of the chips in the mixture is exactly the same as the value of the coefficient of thermal expansion of the outer case material. Therefore, if an electric component is held and housed in a case with a mixture obtained by mixing the above chips with, for example, 80%, the force acting between each part generated during heating or cooling is simply estimated to be reduced to 20%. To be
Here, the filler has to enter the narrow gap between the chips, but this can be dealt with by further crushing the chips or by making them smaller originally.

FIG. 1 is a partially cutaway side view showing an embodiment of an electric device according to the present invention. In FIG. 1, 1 to
3 is the same as in FIG. 4 also shows a filler like FIG. 3, but differs from FIG. 3 as follows. That is, FIG.
Medium 5 is a fragment of the same material as case 1, but in the present invention, the filler 4 is a mixture 8 together with a large number of fragments 5 as shown in the figure.
It is what makes up.

The mixture 8 fills the space between the case 1 and the flexible circuits 2 and 3 which are the electric parts housed therein, whereby the case 1 is formed.
Insulation between the flexible circuits 2 and 3 and positioning of the flexible circuits 2 and 3 in the case 1 are performed.

The arrows 6a, 6b and 7a, 7b are the same as in FIG. That is, the arrow 6a indicates the amount of thermal expansion of the filler 4 when the apparatus is heated (mainly when heating the case 1 for sterilization, etc.), and the arrow 6b also indicates the amount of thermal expansion of the case 1. Further, the arrow 7a indicates the magnitude of the force that the flexible circuit 2 receives from the filling material 4 in the signal line soldering portion between the flexible circuits 2 and 3 during heating, and the arrow 7b indicates that the flexible circuit 3 also receives the same from the filling material 4 during heating. Indicates the magnitude of force.

In the above-mentioned structure, the crushed pieces 5, here the gaps between the crushed pieces 5 formed like adzuki beans, are filled with the filler 4. Since the material of the adzuki bean crushed pieces 5 is the same as that of the case 1, only the filling material 4 having a volume corresponding to the gap between the crushed pieces 5 produces a force during heating. That is, arrow 6
As shown in a, 6b and 7a, 7b, the force applied to the case 1 and the signal wire soldering portion between the flexible circuits 2 and 3 is greatly reduced. Therefore, even if the filler 4 close to the value of the coefficient of thermal expansion of the case 1 is not searched for, that is, even if the filler 4 currently used is used as it is without being changed, heating, cooling (thermal expansion) , Heat contraction) can be alleviated, and cracking of the case 1 and disconnection of signal lines between the flexible circuits 2 and 3 in the case 1 can be prevented.

In the above-mentioned embodiment, the crushed pieces 5 are formed in a red bean shape, but the invention is not limited to this. When the case 1 is, for example, a thermoplastic, the raw material chips can be directly used as the crushed pieces 5, and
When the electric components (flexible circuits 2, 3 etc.) housed in the case 1 are small and the gap between the case 1 and the case 1 becomes narrow, the finely crushed pieces 5 may be used.

FIG. 2 shows an electric component in the electric device of the present invention,
Here, a mounting method of the flexible circuits 2 and 3 will be described. In FIG. 2, (A) shows that after assembling the apparatus head part 101 and the main body part 102, the crushed pieces 5 of the same material as the case 1 are put in first from the hole 21 provided in the case 1 and the same hole 21 is used for filling. An example in which the material 4 is injected later is shown.

(B) shows the apparatus head portion 101 and the main body portion 1.
An example is shown in which, at the stage of assembling 02, the fragments 5 are put into the case 1 from the opening (not shown) of the case 1 before sealing, and after the assembly, only the filler 4 is injected from the hole 21. If the hole 21 is too small to pass the fragment 5, or if the method shown in (A) above is adopted, the fragment 5 floats on the liquid surface side of the filler 4 due to the relationship between the specific gravity and the viscosity of the filler 4 and the fragment 5. And make a baby boom,
Suitable for cases where they are not mixed evenly.

(C) is applied to a large electric device, and is an example in which both the case 1 and the hole 21 are sufficiently large. In this case, the mixture (the mixture 8) in which the crushed pieces 5 are mixed in advance with the filler 4 may be poured into the case 1 through the hole 21 as it is.

In any of the examples (A) to (C),
If the gap between the case 1 and the electric parts (here, the flexible circuits 2 and 3) housed therein is narrow, or if the hole 2
When 1 is small, the fragment 5 may be further finely crushed and used as shown by 51.

[0026]

As described above, according to the present invention, heating and cooling (thermal expansion, thermal contraction) can be performed without searching for a filler having a coefficient of thermal expansion close to that of the case. There is an effect that unnecessarily generated force can be relieved, and cracking of the case and disconnection of signal lines between electric parts in the case can be prevented. In addition, the structure is simple, the physical properties of the mixture can be easily estimated (it should be considered in terms of volume fraction), and there is an effect that it can be easily designed.

[Brief description of drawings]

FIG. 1 is a partially cut side view showing an embodiment of the device of the present invention.

FIG. 2 is a diagram for explaining a method of mounting an electric component in the device of the present invention.

FIG. 3 is a partially cut side view of a conventional device.

[Explanation of symbols]

 1 Case 2 Flexible circuit (electrical part) 3 Flexible circuit (electrical part) 4 Filler 5 Fragment of the same material as the case 8 Mixture

Claims (1)

[Claims] 1. An electric device in which an electric component is housed in a case via a holding member, wherein the holding member is a mixture of a fragment of a substance of the same material as the case and a filler. Electrical equipment.