Electronic circuit device and production method of the same

An electronic circuit device comprises: a printed circuit board mounted with electronic components; a resin-molded portion formed of resin so disposed that the electronic components are covered therewith; a convex connector that has metal terminals for connection and is exposed from the resin-molded portion; and a sealing member wrapped around the resin-molded portion.

CLAIM OF PRIORITY

This application claims priority from Japanese application serial No. 2004-364824, filed on Dec. 16, 2004, the content of which is hereby incorporated by reference into this application.

1. Field of the Invention

The present invention relates to an electronic circuit device having a printed circuit board. More particularly, it relates to an electronic circuit device favorably used in various modules for use in automobiles, motorcycles, agricultural machines, industrial machines, shipboard machines, and the like.

2. Related Art

With respect to automobiles, motorcycles, agricultural machines, machining tools, shipboard machines, and the like, modular electronic circuit devices are used. Such modular electronic circuit devices include engine control modules, motor control modules, and automatic shift control modules. These modules are disposed in vehicle compartments or engine rooms. These modules typically adopt such a construction that a printed circuit board mounting electronic components is fixed on a metal base and they are covered with a cover or a casing.

Recently, a method in which an electronic control unit for an automobile is installed directly on an intake manifold or the like, that is, on-engine method has been proposed. Since the heat resistance of electronic control units using printed circuit boards is 120° C. or so, the on-engine method cannot be adopted. Electronic control units using ceramic boards are high in heat resistance, and thus can adopt the on-engine method; however, they are rather expensive. The on-engine electronic control units need not only high heat resistance, but also need vibration resistance, complete air-tightness and water-tightness better than those of the units installed in the vehicle compartment or the engine room. These requirements are imposed on not only the on-engine electronic control units but also the on-engine sensor modules, such as pressure sensor modules and air flow meter modules.

Japanese Patent Laid-Open No. 2004-111435 discloses an example of an electronic control circuit device using a printed circuit board, which can adopt the on-engine method. The electronic control circuit device according to the patent document is formed integrally by transfer molding a connector and a printed wiring board

When a board is resin-molded by the transfer molding technique, flow properties of resin must be ensured to prevent the voids and the occurrence of deformation in the board. Especially, if there are many restrictions on the stereo structure of a component to be resin-molded, the physical properties, etc of the resin, the productivity lowers. Incase where a resin-molded structure is adopted, the cost of structural parts can be reduced, but the cost-ratio of the connector is increased.

If an attempt is made to enhance functions with a conventional connector structure, the number of connector pins increases, and the dimensions of the connector will increase. Therefore, it is difficult to meet conflicting demands, function enhancement and downsizing.

SUMMARY OF THE INVENTION

An object of the present invention is to provide an electronic circuit device that allows downsizing and cost reduction with reliability.

According to the present invention, an electronic circuit device comprises: a circuit board mounting an electronic component; a resin-molded portion formed of resin for covering the electronic component are covered therewith; a convex connector that has a metal terminal for connection and is exposed from the resin-molded portion; and a sealing member wrapped around the resin-molded portion.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

According to the present invention, an electronic circuit device that allows downsizing and cost reduction with high reliability.

Description will be given to a first example of an electronic circuit device of the present invention with reference toFIG. 1toFIG. 4. As illustrated inFIG. 1, the electronic circuit device10in this example comprises a circuit board11, a convex connector12, a resin-molded portion15, and a sealing member16. The circuit board11is mounted with electronic components, such as a board insert type electronic component111, a surface mount large electronic component112, an IC113, a high heat producing electronic component114, a surface mount chip-type electronic component115, a back mount chip-type electronic component116, and the like. These electronic components111to116are covered with the single resin-molded portion15. Thus, the electronic circuit device10in this example is of resin mold type.

For the material of the resin-molded portion15, thermosetting resins may be used. For example, an epoxy resin for transfer mold that is used in common for semiconductor encapsulation may be used. If there is a great difference in coefficient of thermal expansion between the circuit board11and the resin-molded portion15, a problem results: the electronic circuit device10is deformed by thermal stress, and may be broken in some cases. Therefore, it is desirable that the thermal expansion coefficient of a resin used for the resin-molded portion15should be close to the thermal expansion coefficient of the main material of the circuit board11as much as possible. For the circuit board11, a printed circuit board made mostly from epoxy resin may be used. In this case, an epoxy resin for transfer molding, a thermal expansion coefficient of the resin being 8 to 18×10−6/K, is suitable for the material of the resin-molded portion15.

A major application of epoxy resins for transfer molding is semiconductor encapsulation, and it is usually used for products smaller than the electronic circuit device10in this example. Therefore, many epoxy resins for transfer molding are short in a spiral flow, which is a distance by which a resin can flow from time when it is heated during resin molding to time when it is hardened under heating. Consequently, when an epoxy resin for transfer mold is used for the material of the resin-molded portion15, it is required to select one whose spiral flow is equal to or longer than the size of the electronic circuit device10.

FIG. 2is an enlarged cross sectional view of an end of the electronic circuit device10illustrated inFIG. 1. The convex connector12is formed by extending the circuit board11. That is, the convex connector12is formed simultaneously with the circuit board11in the production process of the circuit board11. Therefore, the convex connector12is formed of the same material as that of the circuit board11.

The upper face and lower face of the convex connector12are respectively provided with metal terminals13and14for connection. These metal terminals13and14for connection are formed by extending metal wirings117formed on the front face of the circuit board11and metal wirings118formed on its back face. That is, the metal terminals13and14for connection of the convex connector12are formed simultaneously with the metal wirings117and118of the circuit board11in the production process of the circuit board11.

The sealing member16is formed along the periphery of the resin-molded portion15, in proximity to the convex connector12. A groove for receiving the sealing member16is formed along the periphery of the resin-molded portion15. When the convex connector12is connected with a concave connector, the sealing member16provides a waterproof construction for the joint. The sealing member16may be formed of any material as long as it is an elastic material having heat resistance, oil resistance, resistance to chemicals, and the like. For example, it may be formed of rubber, resin, or the like.

In the example illustrated in the figure, the sectional shape of the sealing member16includes two crests and one trough. A construction having at least two crests and at least one trough is desirable. Constructing the sealing member having the sectional shape including two crests brings the following advantage. When the convex connector12is connected with a concave connector, the crests of the sealing member are easily deformed. Therefore, the force required for inserting/withdrawing the convex connector12is reduced, and the workability in installing the electronic circuit device10can be enhanced. The sections of the sealing member16may be in any other shape as long as a sufficient waterproofing function can be provided.

The O-ring17provided at the base of the convex connector12is used to prevent resin from leaking to the convex connector12when the circuit board11is encapsulated with the resin. This will be described later.

FIG. 3is an enlarged view of the convex connector12inFIG. 1as viewed from above A, andFIG. 4is an enlarged view of the convex connector12inFIG. 1as viewed from left B.

In this example, the metal terminals13and14for connection of the convex connector12are a plurality of strips so formed that they are arranged in parallel with one another at equal intervals. However, any other configuration may be adopted. As illustrated inFIG. 4, the metal terminals13for connection on the upper face and the metal terminals14for connection on the lower face are identical in shape with each other. Therefore, both are symmetrical with each other. In this example, the metal terminals13and14for connection are formed on both faces of the convex connector12. Instead, the metal terminals for connection may be provided on one face. The metal terminals13for connection only on the upper face and the metal terminals14for connection on the lower face may be disposed in a staggered configuration as long as they are identical in dimensions with each other.

In the example illustrated inFIGS. 1 to 4, the convex connector12is provided on one side of the circuit board11. Instead, the convex connector may be provided on two opposite sides, on three sides, or on all the four sides. If the convex connector12is provided on a plurality of sides, the sealing member16is provided in correspondence with each of the convex connectors12.

FIG. 5illustrates the convex connector12of the electronic circuit device10inFIG. 1as is connected with a concave connector40. The concave connector40has a concave portion42formed in its housing41, and a hole43is formed in the bottom of the concave portion42. In this hole43, metal terminals44and45for connection and a receiving member46are provided. The metal terminals44and45for connection have spring constructions formed by folding strip-shaped metal plates. The metal terminals44and45for connection are connected with harnesses47. Water tight plugs48are installed around the harnesses47for connection.

When the convex connector12of the electronic circuit device10is inserted into the concave portion42of the housing41, the following takes place: the end of the convex connector12goes into between two metal terminals44and45for connection. As a result, the metal terminals44and45for connection are brought into contact with the metal terminals13and14for connection of the convex connector12. When the convex connector12of the electronic circuit device10is further inserted into the concave portion42of the housing41, the following takes place: the convex connector12is abutted against the receiving member46, and thus the electronic circuit device10cannot be further pushed inward.

The sealing member16of the electronic circuit device10is pressed against the inner wall of the concave portion42of the housing41, and is deformed there. As a result, the concave portion42of the housing41is sealed from the outside, and water, oil, dust, and the like are prevented from entering the concave portion from the outside.

It is desirable that the position in which the sealing member16is brought into contact with the concave portion42of the housing41should be far away from the metal terminals13and14for connection as much as possible. Thus, the stress produced between the electronic circuit device10and the concave connector40, due to pinching force, vibration, or the like can be absorbed by the sealing member16, not by the metal terminals for connection.

As illustrated in the figure, the width of the electronic circuit device10will be let to be D, and the distance between the end of the resin-molded portion15of the electronic circuit device10and the sealing member16will be let to be H. At this time, it is desirable that H should be substantially twice D.

The construction of the convex connector12of the electronic circuit device10and the concave connector40may be the same as the PCI slot construction used in common for expansion boards for personal computers. However, it is desirable that the metal terminals44and45for connection of the concave connector40should be of spring construction as in the example illustrated in the figure. Thus, the metal terminals44and45for connection of the concave connector40are pressed against the metal terminals13and14for connection of the convex connector12. As a result, both are brought into contact with each other with reliability. The metal terminals44and45for connection of the concave connector40may be of any construction other than spring construction. In this case, however, it is desirable that their shape should be the same as or close to that of the metal terminals13and14for connection of the convex connector12.

The electronic circuit device10in this example adopts a combination of the following constructions: the construction in which the electronic components on the circuit board11are resin-molded; and the slot construction used in common for expansion boards for personal computers. Thus, the electronic circuit device for use in automobiles, agricultural machines, industrial machines, shipboard machines, and the like can be constructed without impairing the following: the watertightness, reliability, and low-cost properties of conventional electronic circuit devices10.

Description will be given to a method for resin-molding the electronic circuit device10with reference toFIG. 6andFIG. 7. First, the O-ring17is wrapped around the base portion of the convex connector12of the circuit board11mounted with electronic components. Next, the circuit board11is sandwiched between two molds61and62.

The cavity63formed between the two molds comprises a first portion63A corresponding to the exterior shape of the resin-molded portion15and a second portion63B in which the convex connector12is placed. The second portion63B is larger than the outer dimensions of the convex connector12so that the convex connector12will not be brought into contact with the inner walls of the molds. The O-ring17is disposed at the entrance to the second portion63B.

When the resin is injected into the cavity63through a resin injection portion64, the resin is guided to the first portion63A, but the O-ring17prevents it from entering the second portion63B.

In this example, the above-mentioned use of the O-ring17prevents resin from being applied to the metal terminals for connection of the convex connector12. Thus, the convex connector12exposed from the resin-molded portion15can be formed as illustrated inFIG. 1. If the O-ring is not used, the second portion63B of the cavity63must be so constructed that it has the same shape as the outside shape of the convex connector12. More specific description will be given. The molds61and62are brought into direct contact with the convex connector12, and thus resin is prevented from being applied to the metal terminals for connection of the convex connector12. However, if the molds61and62are brought into direct contact with the convex connector12, problems arise: there is the possibility that the metal terminals for connection are damaged, and the molds must be fabricated with high accuracy.

The O-ring17is used when the resin-molded portion15is formed, and is unnecessary when the finished electronic circuit device10is used. When the electronic circuit device10is in use, the O-ring17is disposed in the waterproofed enclosed space as illustrated inFIG. 1. Therefore, the O-ring17need not be provided with water resistance, and further need not be provided with oil resistance, resistance to chemicals, heat resistance, vibration resistance, and the like. As a result, a very inexpensive material can be selected.

Projections65are formed on the inner surfaces of the molds61and62, and as a result, a projection65is formed throughout the inner circumferential surface of the cavity63. A groove for housing the sealing member16is formed throughout the circumference of the resin-molded portion15by this projection65.

FIG. 7is a sectional view of the circuit board11placed in the cavity63between the two molds as viewed from the direction of arrow A ofFIG. 6. When the circuit board11wrapped with the O-ring17is sandwiched between the two molds61and62, the O-ring17is brought into contact with an end of the second portion63B of the cavity63. As a result, it can be broken. If the O-ring17is broken, its sealing function does not work, which result in the entry of resin into the second portion of the cavity63.

The following measure illustrated inFIG. 7is effective in avoiding this: the areas of the second portion63B of the cavity63with which areas the O-ring17is to be brought into contact are provided beforehand with a clearance angle θ.

With reference toFIG. 6andFIG. 7, description has been given to a production method for an electronic circuit device10provided on one side with a convex connector12. Where an electronic circuit device10with a convex connector12provided on two, three, or four sides is produced, the following measures must be taken: the molds are provided with a shape corresponding to a plurality of the convex connectors12and accordingly required resin injection portions64.

FIG. 8illustrates a second example of an electronic circuit device of the present invention. In this example, a projection18is provided on the outer surface of the resin-molded portion15of the electronic circuit device10. The housing41of a concave connector40is provided with a pivot50and a lever51. The convex connector12of the electronic circuit device10is inserted into the concave portion of the housing of the concave connector40. Thereafter, the lever51is pivoted about the pivot50to engage it with the projection18. As a result, the convex connector12of the electronic circuit device10is locked on the concave connector40with reliability.

In this example, when the projection18on the electronic circuit device is engaged with the lever51of the concave connector40, the electronic circuit device10is prevented from being displaced in the axial direction. Therefore, the electronic circuit device10is prevented from coming off. In addition, the convex connector12need not be abutted against the receiving member46of the concave connector40. Therefore, the convex connector12does not receive strong pressing force from the receiving member46. Furthermore, the electronic circuit device10is prevented from wobbling to the left and right. This prevents wear and breakage due to pinching force, vibration, or the like that are likely to occur in the following areas: the area of contact between the metal terminals13and14for connection of the convex connector12and the metal terminals44and45for connection of the concave connector40; and the area of connection between the sealing member16and the housing of the concave connector40.

In the example inFIG. 8, one lever51is provided. Instead, a lever may be provided in two places on the upper and lower sides or on the left and right sides.

The projection18may be formed of the same material as that of the resin-molded portion15as part of the resin-molded portion15. More specific description will be given. The molds are provided with concave portion corresponding to the outside shape of the projection18. Thus, the projection can be formed simultaneously with the resin-molded portion15. If the resin-molded portion15is formed of a material, such as epoxy resin, weak against shear stress, the sectional area of the projection may be increased. Or, a metal piece may be resin-molded therein.

FIG. 9illustrates a third example of an electronic circuit device of the present invention. In this example, a recess19A is formed in the outer surface of the resin-molded portion15of the electronic circuit device10. The housing41of a concave connector40is provided with a protruded plate52, and a hook53is provided at its end. When the convex connector12of the electronic circuit device10is inserted into the concave portion of the housing of the concave connector40, the hook53is engaged with the recess19A. As a result, the convex connector12of the electronic circuit device is locked in the concave connector40with reliability. To remove the convex connector12from the concave connector40, one end of the hook53only has to be pushed. The other end of the hook53is moved by the principle of leverage in the opposite direction to the direction in which the hook53is pushed, and it goes out of the recess19A.

In the example inFIG. 9, one hook53is provided. Instead, a hook may be provided in two places on the upper and lower sides or on the left and right sides.

In this example, when the electronic circuit device10is inserted into the concave connector40, the hook53is automatically engaged with the recess19A. Therefore, the following advantage is brought: a human error that can occur in the example illustrated inFIG. 8involving use of a lever51, that is, forgetting about fixing the circuit board device is prevented.

In this example, the hook53is abutted against the recess19A in the resin-molded portion15. Therefore, while pressing force is applied to the recess19A in the resin-molded portion, shear stress is not exerted. Unlike the second example inFIG. 8, therefore, it is unnecessary to provide a metal piece or the like in the hook so that it can withstand shear stress. The material of the resin-molded portion15and the hook53of the concave connector40can be selected from among a wide range of materials.

FIG. 10illustrates a fourth example of an electronic circuit device of the present invention. In this example, the convex connector12of the electronic circuit device10includes metal pins21. The metal pins21are substantially in L shape, and one end of them are protruded from the electronic circuit device10and form metal terminals for connection. The other ends are inserted into holes in the circuit board11so that they penetrate the circuit board. In this example, therefore, the metal terminals for connection are disposed on one side plane of the electronic circuit device10including the circuit board11.

In the first example illustrated inFIG. 1, part of the circuit board11is exposed from the resin-molded portion15. In this example, meanwhile, the whole of the circuit board11is covered with the resin-molded portion15. A holding plate22is attached to an end of the resin-molded portion15, and the holding plate22is connected with an aligning plate23. The aligning plate23has convex portions, and the ends of the convex portions are abutted against the front face of the circuit board11. The metal pins21penetrate the holding plate22, and they are thereby supported and fixed.

In the example inFIG. 10, two metal pins21are provided. Instead, one metal pin may be provided, or three or more metal pins may be provided.

If a plurality of metal pins21are provided, they can be disposed in a line in parallel with the end face of the circuit board11. Instead, they may be disposed in two or more lines.

Description will be given to a production method for the electronic circuit device in this example. First, the holding plate22provided with the metal pins21and aligning plate23is prepared. The aligning plate23may be formed integrally with the holding plate22, that is, the aligning plate may be formed of the same material as that of the holding plate. The metal pins21may be formed integrally with the holding plate22by insert molding. Instead, the following method may be adopted: holes are formed in the holding plate22and the aligning plate23, and the metal pins are inserted and fixed therein. Next, the circuit board11and the holding plate22are assembled together. The metal pins21are inserted into the holes in the circuit board11, and the end of the aligning plate23is abutted against the front face of the circuit board11. The metal pins21and the wires on the circuit board11are connected together by soldering. Thus, the holding plate22having the metal pins21is assembled to the circuit board11.

The aligning plate23is provided with a function of positioning the holding plate22relative to the circuit board11. The accuracy of positioning the metal pins21in the circuit board11can be enhanced by this function.

The thus obtained assembly is sandwiched between two molds, and the cavity formed between the molds is filled with resin. In this example, it is unnecessary to use the O-ring used in the example illustrated inFIG. 1.

FIG. 11illustrates a fifth example of an electronic circuit device of the present invention. In this example, the convex connector12of the electronic circuit device includes metal pins24. The metal pins24are substantially in L shape, and one ends of them are protruded from the electronic circuit device and form metal terminals for connection. The other ends are bent into L shape, and connected to the metal wirings117and118on the surfaces of the circuit board11. That is, the inner ends of the metal pins24are face-mounted on the circuit board11. In this example, the metal terminals for connection are symmetrically disposed on the side plane of the electronic circuit device10including the circuit board11.

Description will be given to a production method for the electronic circuit device in this example. First, the holding plate22provided with the metal pins24is prepared. The metal pins24may be formed integrally with the holding plate22by insert molding. Instead, the following method may be adopted: holes are formed in the holding plate22, and the metal pins are inserted and fixed therein. Next, the circuit board11and the holding plate22are assembled together. The end of the circuit board11is inserted into between the inner ends of the two metal pins24. The metal pins24and the metal wirings117and118on the circuit board11are connected together by soldering. Since the inner ends of the metal pins24are pressed against the circuit board11by spring force from the metal pins24, soldering of the metal pins24may be omitted. Thus, the holding plate22having the metal pins is assembled.

Subsequently, the thus obtained assembly is sandwiched between two molds, and the cavity formed between the molds is filled with resin. In this example, it is unnecessary to use the O-ring used in the example illustrated inFIG. 1.

In this example, the circuit board11is sandwiched between the inner ends of the metal pins positioned on both sides. Therefore, an even number of metal pins are provided. In this example, it is unnecessary to use the aligning plate in the example illustrated inFIG. 10.

Description will be given to a sixth example of an electronic circuit device of the present invention with reference toFIG. 12andFIG. 13.FIG. 12is an enlarged sectional view of an end of the electronic circuit device in this example.FIG. 13is an enlarged sectional view of the electronic circuit device in this example as a front view.

As in the first example inFIG. 1, the convex connector12of the electronic circuit device in this example is formed by extending the circuit board11. The circuit board11usually has a laminated structure comprising a plurality of layers, and metal wirings are formed not only on the surfaces but also in internal layers of the board. A plurality of these metal wirings formed in different layers are electrically connected together through through holes25.

In this example, metal terminals13and14for connection are formed on the outer surface of the convex connector12at the end12A of the convex connector12. Meanwhile, the metal terminals13and14for connection are formed in internal layers26of the convex connector12at the root portion12B of the convex connector12. The metal terminals13and14for connection at the end12A of the convex connector12are electrically connected with the metal terminals13and14for connection at the root portion12B through the through holes25.

Description will be given to a resin molding method for the electronic circuit device in this example. The circuit board11mounted with electronic components is sandwiched between two molds. The ends of the molds sandwich the base portion12B of the convex connector12from both sides. At the base portion12B of the convex connector12, the metal terminals for connection are formed in internal layers. Therefore, if the ends of the molds are brought into contact with the outer surface of the convex connector12, the metal terminals for connection are not damaged or broken. In this example, it is unnecessary to use the O-ring used in the example illustrated inFIG. 1.

It is preferable that the area of contact between the molds and the circuit board11should be widened as much as possible and the contact faces of the upper and lower molds should be symmetrically structured. Thus, stress exerted on the circuit board11is reduced. Further, even if there is warpage in the circuit board11, pressing force can be uniformly applied so that the warpage will be eliminated.

Thermosetting resin is poured into the cavity formed between the two molds. The cavity has a shape corresponding to the outside shape of the resin-molded portion. Therefore, it is unnecessary to provide the first portion63A as illustrated inFIG. 6.

In considerable cases, only through holes25that penetrate the circuit board11are obtained from the viewpoint of cost and standardization. If through holes25are provided between the end12A and the base portion12B of the convex connector12, a problem arises. The metal wirings13and14for connection on the upper face and the lower face of the end12A of the convex connector12cannot be formed in symmetrical positions as in the example illustrated inFIG. 4.

As illustrated inFIG. 13, the metal wirings13and14for connection on the upper and lower faces of the end12A of the convex connector12are identical in number with each other. However, they are disposed in a staggered configuration on the upper and lower faces. As a result, the following advantage is brought: when the convex connector12is engaged with the concave connector40, the pressing forces applied to the upper face and lower face of the circuit board11through the metal terminals for connection become identical. As a result, production of bending stress in the circuit board11is avoided.

FIG. 14illustrates an electronic circuit device of the present invention with a protective cover30attached over the convex connector12. The protective cover30comprises a frame member31and beam-like projections32, and hooks33are provided at the ends of the frame member31. Recesses19B are formed in the outer surface of the resin-molded portion15of the electronic circuit device. When the convex connector12of the electronic circuit device10is inserted into the protective cover30, the following takes place: the beam-like projections32are abutted against an end of the resin-molded portion15, and the electronic circuit device10cannot be further pushed in. Thus, the end of the convex connector12is prevented from being abutted against the protective cover30. At this time, the hooks33are engaged with the recesses19B. As a result, the protective cover30is fixed on the electronic circuit device10with reliability. To remove the protective cover30, the hooks33are bent outward, and then the protective cover30is pulled.

The protective cover30is used when the electronic circuit device10is transported and stored. It is unnecessary when the electronic circuit device10is actually installed in an automobile, a motorcycle, an agricultural machine, an industrial machine, a shipboard machine, or the like. Therefore, the protective cover30does not need such a high reliability as the electronic circuit device10needs. It may be formed of PET used for beverages and the like or an inexpensive material corresponding thereto. However, an appropriate material must be selected so that the attached protective cover30will not come off from the electronic circuit device10due to moisture absorption, thermal deformation, or the like.

FIG. 15illustrates an example of the construction of a concave connector40used for the electronic circuit device of the present invention. The housing41of the concave connector40has an attaching portion55, and the attaching portion55is provided with holes56. When this concave connector40is attached to a structure70, such as automobile, motorcycle, agricultural machine, industrial machine, shipboard machine, or the like, the following procedure can be taken: screw holes71are formed in the structure70, and screws72are engaged with the screw holes71in the structure70through the holes56.

In addition to the method in which the screws72are used, various methods can be used to attach and fix the concave connector40to the structure70. However, the method in which the screws72are used is preferable in terms of reliability and cost.

With the method in this example, the electronic circuit device10and the concave connector40are fixed as a single-piece construction on the structure70. The resonance frequency of the single-piece construction comprising the electronic circuit device10and the concave connector40is lower than the resonance frequency of the electronic circuit device10. When it is actually used, therefore, there is the possibility that vibration equivalent to the resonance frequency is applied. In such a case, the electronic circuit device10or the concave connector40is provided with a beam structure, the thickness is increased and the length is reduced, or the like measures are taken. Thus, the resonance frequency is increased, and a construction resistant to stress due to vibration can be obtained.

By providing resistance to vibration as mentioned above, it is made possible to install the electronic circuit device10and the concave connector40in this example on a structure, such as automobile, motorcycle, agricultural machine, industrial machine, shipboard machine, or the like. As a result, installation workability and maintenance workability can be enhanced.

FIG. 16illustrates the construction of another example of a concave connector40used for the electronic circuit device of the present invention. The concave connector40in this example has three concave portions42A,42B, and42C formed in its housing41. The first and second concave portions42A and42B may be identical in structure with the concave portion42of the concave connector40illustrated inFIG. 5. Metal wirings49are provided in the housing41. One ends of the metal wirings49are connected with the metal terminals for connection disposed on the bottom of the first and second concave portions42A and42B. The other ends are connected with the terminals49A protruded on the bottom of the third concave portion42C. The terminals of the third concave portion42C form convex connectors.

To install the concave connector in this example in a structure70, such as automobile, motorcycle, agricultural machine, industrial machine, shipboard machine, or the like, screws72are used as in the example inFIG. 15. The example illustrated inFIG. 16is provided with two concave portions, that is, slots so that two electronic circuit devices can be attached thereto. Instead, two or more slots may be provided like PCI slots in personal computers.

A plurality of electronic circuit devices10A and10B can be attached to the concave connector in this example. Therefore, if this is used for, for example, a controller, waste associated with the structure of the controller can be reduced. The heat radiation structure and noise resistance can also be improved by the following measure, for example: the first electronic circuit device10A is mounted with computing function elements with a microcomputer at the nucleus; and the second electronic circuit device10B is mounted with semiconductor devices, such as FET, for controlling large currents.

With the concave connector in this example, functions provided for the following can be easily changed by replacing the electronic circuit devices10A and10B: automobiles, motorcycles, agricultural machines, industrial machines, shipboard machines, or the like. A case where the concave connector in this example is mounted on an engine will be taken as an example. Where the same engine is mounted in different types of vehicles, electronic circuit devices10A and10B having different control circuits are prepared. Different functions can be provided by installing different electronic circuit devices from vehicle type to vehicle type.

In addition, if the necessity for enhancing the functions of a control circuit arises in the future, that can be coped with by replacing only the required electronic circuit devices as needed. If a problem arises with respect to the functions of a specific control circuit, it can also be solved by taking the same measure.

The metal wirings49of the concave connector can also be provided with a desired control circuit, an arithmetic circuit, or the like. In this case, it is possible to replace only the concave connector without changing the electronic circuit devices10A and10B. A case where the concave connector in this example is mounted on an engine will be taken as an example. Where the same engine is mounted in different types of vehicles, the same electronic circuit devices10A and10B are prepared, and concave connectors having different control circuits are prepared. Different functions can be provided by installing different concave connectors from vehicle type to vehicle type.

The electronic circuit device and concave connector according to the present invention can be used for automobiles, motorcycles, agricultural machines, industrial machines, shipboard machines, and the like. Where the present invention is used for an automobile, it is applicable to control modules such as engine control module, motor control module, and automatic shift control module, and sensor modules such as pressure sensor module and air flow meter module. This makes it possible to easily attain the effects of the enhancement of productivity of these modules and reduction of their size and cost.

Further, the present invention is applicable to the following items: brake control module that provides active safety function expected to evolve in the future; control modules such as suspension control module, steering control module, air bag control module, and seat belt control module; measurement modules such as following distance measurement module; and communication modules for information exchange with the outside of the vehicle via radio waves for obtaining the functions of ITS and the like, such as cellular phone communication module, ETC communication module, GPS communication module, and VICS communication module. The electronic circuit device and concave connector according to the present invention is excellent in resistance to chemicals. This makes it possible to enhance the degree of freedom in mounting control modules for equipment utilizing chemical change, such as fuel battery control module and lithium ion battery charge/discharge control module.

Up to this point, description has been given to examples of the present invention. However, the present invention is not limited to the above-described examples, and it will be understood by those skilled in the art that various changes may be resorted to within the scope of the invention described in the claims.