JP7836228B2 - Electronic control unit - Google Patents

Description

This invention relates to an electronic control device.

Electronic control units installed in the engine compartment have many requirements, such as waterproofing, heat resistance, corrosion resistance, vibration resistance, and EMC (Electromagnetic Compatibility). Furthermore, in addition to the aforementioned requirements, on-board electronic control units (automotive electronic control units) are required to have a sealed structure. Because the inside of the engine compartment is strongly influenced by the vehicle's environment, electronic control units installed in the engine compartment require a particularly high level of sealing. In such cases, a major factor affecting electronic control units in the engine compartment is the fluctuation of pressure applied to the electronic control unit.

The pressure applied to the electronic control unit fluctuates due to changes in the vehicle's altitude and the temperature inside the engine compartment. To address these pressure fluctuations, one might consider installing a breathing filter on the electronic control unit's casing. However, installing a breathing filter would compromise the requirement for a sealed structure for the electronic control unit. Furthermore, the electronic control unit's casing must be made of metal to withstand the loads imposed by these pressure fluctuations.

The electronic control unit has a structure in which a printed circuit board (PCB) is housed inside a casing. Various electronic components are mounted on the PCB. Furthermore, the number of electronic components mounted on the PCB is increasing with the sophistication of vehicles. As a result, electronic control units are becoming larger and heavier.

Among the performance requirements for electronic control units installed in the engine compartment, the demands regarding waterproofing and corrosion resistance are particularly stringent. Therefore, electronic control units must have a structure that does not compromise waterproofing or corrosion resistance. Furthermore, when mounting electronic control units in the engine compartment, brackets are used. In this case, it is necessary to ensure a large contact area between the bracket and the electronic control unit to accommodate the increased weight due to its larger size, even in the harsh environment of the engine compartment. To ensure this contact area, a flange is provided on the outer periphery of the electronic control unit's housing, and the bracket is attached to the electronic control unit by gripping this flange. In such cases, the outer end surface of the flange must be flush (flat) to prevent the sealing material that seals the flange airtight from leaking onto the contact surface with the bracket.

Furthermore, in electronic control units mounted in the engine compartment, the printed circuit board (PCB) protected by the enclosure must also satisfy electrical requirements. The PCB has ground (GND) wiring that is electrically connected (conductive) to the metal enclosure. In this case, the electrical resistance between the PCB's ground and the enclosure must be between 470 kΩ and 1 MΩ. Additionally, the PCB of the electronic control unit must be protected from static electricity applied to it from the outside, and from radiated noise generated both inside and outside the electronic control unit. If external noise enters the electronic control unit, that noise may reflect off the inner surface of the enclosure and adversely affect the electronic control unit.

On the other hand, to counteract radiated noise generated within the electronic control unit, it is necessary to dissipate the charge accumulated in the enclosure to the outside of the electronic control unit via the ground of the printed circuit board. To dissipate the aforementioned radiated noise to the outside of the electronic control unit, it is necessary to connect the metal enclosure and the ground of the printed circuit board with the low electrical resistance mentioned above. The enclosure of the electronic control unit is constructed by combining two enclosure members to form a space for housing the printed circuit board inside. The printed circuit board is attached to one of the enclosure members with metal screws. Therefore, electrical conductivity can be established between one enclosure member and the printed circuit board via the screws. However, there is no point of electrical conductivity between the printed circuit board and the other enclosure member. Therefore, in order to connect the metal enclosure and the ground of the printed circuit board with the low electrical resistance mentioned above, the two enclosure members must be electrically conductive to each other.

Conventionally, a configuration has been adopted in which flange portions are formed on the outer periphery of one housing member and the outer periphery of the other housing member, and opposing surfaces are formed on each flange portion, thereby making electrical contact between the two housing members (see, for example, Patent Document 1).

International Publication No. 2021/260992

In recent years, the size of in-vehicle electronic control units has increased significantly, for example, to 260 mm x 240 mm in length, which is about 1.5 times larger than the typical size of conventional electronic control units. This increases the likelihood of warping during the manufacturing process of each housing component, potentially preventing the opposing surfaces of the flanges from making proper contact.

The object of the present invention is to provide an electronic control device that can reliably establish electrical conductivity between two housing members constituting a metal housing through contact between opposing surfaces.

To solve the above problems, for example, the configuration described in the claims can be adopted.
The present invention includes several means for solving the above-mentioned problems, but one example is an electronic control device comprising a printed circuit board on which electronic components are mounted and a metal housing for housing the printed circuit board. The housing comprises a first housing member having a first flange portion on which a first opposing surface is formed, and a second housing member having a second flange portion on which a second opposing surface is formed and positioned opposite the first opposing surface. A convex portion is formed on at least one of the first and second opposing surfaces in a manner that protrudes from the opposing surface, and the first and second opposing surfaces are in contact on the side opposite to the convex portion.

According to the present invention, two housing members constituting a metal housing can be reliably electrically connected by contact between their opposing surfaces.
Other issues, configurations, and effects not mentioned above will be clarified by the following description of the embodiments.

This is an exploded perspective view of the electronic control device according to the first embodiment, viewed from diagonally above. This is an exploded perspective view of the electronic control device according to the first embodiment, viewed from a diagonal downward angle. This is a partial cross-sectional view of an electronic control device according to the first embodiment. This is a schematic diagram showing the arrangement of opposing surfaces. This is a side view of the electronic control device according to the first embodiment. This is an enlarged plan view of a part of the base of the electronic control device according to the first embodiment. This is a cross-sectional view taken along line A-A in Figure 6. This is a cross-sectional view taken along line B-B in Figure 6. This is an enlarged view of a part of the base of the electronic control device according to the second embodiment. This is a cross-sectional view taken along line C-C in Figure 9. This is a cross-sectional view illustrating a modified example of the second embodiment. This is an enlarged view of a part of the base of the electronic control device according to the third embodiment. This is a cross-sectional view taken along line D-D in Figure 12. This is an enlarged longitudinal cross-sectional view of the main part of the electronic control device according to the fourth embodiment.

Embodiments of the present invention will be described in detail below with reference to the drawings. In this specification and the drawings, elements having substantially the same function or configuration are denoted by the same reference numerals, and redundant descriptions are omitted. The electronic control devices described below are, for example, mounted in a vehicle to control the engine, transmission, and the like.

<First Embodiment>
Figure 1 is an exploded perspective view of the electronic control device according to the first embodiment, viewed from diagonally above. Figure 2 is an exploded perspective view of the electronic control device according to the first embodiment, viewed from diagonally below. Figure 3 is a partial cross-sectional view of the electronic control device according to the first embodiment.

As shown in Figures 1 to 3, the electronic control unit 1 comprises a housing 2, a printed circuit board 3, a base 4, a sealing material 5, multiple (three in the illustrated example) connectors 6, and a connector sealing material 51.

The housing 2 and base 4 are components that make up the metal housing 10. The housing 2 and base 4 are preferably made of aluminum. The housing 2 is preferably formed by an aluminum die-casting method using a mold. The same applies to the base 4. The housing 2 is provided as an example of a first housing component, and the base 4 is provided as an example of a second housing component. The housing 2 has the same number of openings 9 as the connector 6.

The enclosure 10 protects the printed circuit board 3 from water and foreign matter. Furthermore, the enclosure 10 dissipates heat generated by the electronic components mounted on the printed circuit board 3 and shields against noise generated within the enclosure 10 or external noise. Therefore, if the enclosure 10 were constructed from a thermoplastic resin such as PBT (polybutylene terephthalate), the heat dissipation function would be insufficient, and the noise shielding function would not be achieved. Thus, the enclosure 10 must be made of metal. Moreover, high-performance electronic control devices for engines need to protect their electronic components not only from external noise but also from noise generated by specific electronic components on the printed circuit board 3 (for example, electronic components with CPUs that operate at high frequencies), i.e., internal noise. Therefore, if a resin enclosure were used, the noise shielding effect would not be achieved, potentially leading to malfunctions of the electronic components.

The housing 10 is formed in a rectangular shape in plan view. In this embodiment, as an example, the housing 10 is formed in a rectangular shape in plan view. The lengths of the long and short sides of the housing 10 are, for example, 260 mm x 240 mm. This size is large for an electronic control unit 1 to be placed within the engine compartment. The housing 10 forms a space capable of housing the printed circuit board 3 (hereinafter also referred to as the "board storage space") by assembling the housing 2 and the base 4 together.

The housing 2 has a first flange portion 11, and the base 4 has a second flange portion 12. The first flange portion 11 is formed on the outer circumference of the housing 2, extending around its entire circumference (all four sides). The second flange portion 12 is formed on the outer circumference of the base 4, extending around its entire circumference. As shown in Figure 3, the first flange portion 11 and the second flange portion 12 are positioned facing each other when the housing 2 and base 4 are assembled.

Furthermore, the housing 2 has a first circumferential wall portion 14, and the base 4 has a second circumferential wall portion 15. The first circumferential wall portion 14 is formed integrally with the first flange portion 11, and the second circumferential wall portion 15 is formed integrally with the second flange portion 12. The first flange portion 11 is positioned to protrude outward from the outer surface of the first circumferential wall portion 14, and the second flange portion 12 is positioned to protrude outward from the outer surface of the second circumferential wall portion 15. The first circumferential wall portion 14 and the second circumferential wall portion 15 form a substrate storage space when the housing 2 and the base 4 are assembled. At that time, the first circumferential wall portion 14 is positioned outside the second circumferential wall portion 15. The lower end portion 14a of the first circumferential wall portion 14 is positioned to protrude below the first flange portion 11.

A first groove 41 and a second groove 42 are formed on the outside of the second peripheral wall portion 15. The first groove 41 is a groove for filling with sealing material 5. The first groove 41 is formed adjacent to the second peripheral wall portion 15. The second peripheral wall portion 15 serves to block the sealing material 5 when it is applied to the first groove 41 during the manufacturing process of the electronic control device 1. The second groove 42 is a groove for accommodating leaked sealing material 5 if it leaks from the first groove 41 during the manufacturing process of the electronic control device 1. The first groove 41 is formed around the entire circumference of the second flange portion 12 so as to surround the substrate storage space, and the second groove 42 is formed around the entire circumference of the second flange portion 12 so as to surround the first groove 41. The first groove 41 and the second groove 42 are formed on the upper surface side of the second flange portion 12. The second groove 42 is formed on the outer circumference of the second flange portion 12, further away from the first groove 41. The first groove 41 is wider than the second groove 42. Furthermore, the first groove 41 is deeper than the second groove 42.

The first flange portion 11 is positioned so as to overlap with the second flange portion 12 when the electronic control device 1 is viewed from above. As shown in Figure 3, the first flange portion 11 has a first opposing surface 31, and the second flange portion 12 has a second opposing surface 32. The first opposing surface 31 and the second opposing surface 32 are positioned facing each other. The second groove portion 42 is formed in a concave shape on the second opposing surface 32. The upper end portion 15a of the second peripheral wall portion 15 is positioned higher than the second opposing surface 32.

The printed circuit board 3 is housed inside the housing 10. The printed circuit board 3 is attached to the housing 2 by metal screws (not shown). At least four corners of the printed circuit board 3 have holes 3a for screw fastening. These holes 3a are electrically connected to the ground line (not shown) of the printed circuit board 3. Specifically, an electrode pad connected to the ground line is formed around at least one of the multiple holes 3a provided in the printed circuit board 3, and the hole 3a is formed in the area where this electrode pad is formed. Meanwhile, the housing 2 has a board mounting portion 16 (Figure 2) for attaching the printed circuit board 3, and screw holes 17 are formed in this board mounting portion 16. The metal screws engage with the screw holes 17 in the housing 2 through the holes 3a in the printed circuit board 3 and are tightened in this state. At this time, the screw heads are pressed against the electrode pads by the tightening force of the screws themselves. Therefore, the ground line of the printed circuit board 3 is electrically connected to the housing 2 via the screws.

The printed circuit board 3 is equipped with electronic components (not shown) in addition to the connector 6 described above. Furthermore, a heat dissipation pad 7 is formed on the printed circuit board 3. The heat dissipation pad 7 is designed to dissipate the heat generated by the electronic components mounted on the printed circuit board 3 to the housing 2. Meanwhile, a heat dissipation base 18 (Figure 2) is formed on the housing 2, corresponding to the heat dissipation pad 7. The heat dissipation pad 7 is bonded to the heat dissipation base 18 of the housing 2 using a thermally conductive adhesive (not shown). As a result, the heat generated by the electronic components is transferred to the housing 2 through the heat dissipation pad 7 and the heat dissipation base 18, and then released from the outer surface of the housing 2.

The sealant 5 seals the mating portion between the housing 2 and the base 4. A silicone adhesive is preferred as the sealant 5. Silicone resin has several advantages, including excellent adhesion to metals, resistance to saltwater and water, and sufficient heat and weather resistance to withstand harsh environments such as engine compartments where high temperatures are present. However, the sealant 5 is not limited to silicone resin; for example, epoxy resin may also be used.

In the manufacturing process of the electronic control unit 1, first, the printed circuit board 3, on which electronic components including the connector 6 are mounted, is attached to the housing 2 by screw fastening. Next, the sealing material 5 is applied to the first groove 41 of the base 4.

Next, the housing 2 and base 4 are assembled. At this time, with the first opposing surface 31 of the housing 2 and the second opposing surface 32 of the base 4 facing each other, the lower end portion 14a of the first peripheral wall portion 14 is embedded in the sealing material 5 in the second groove portion 42. At this time, depending on the amount of sealing material 5 applied, some of the sealing material 5 may overflow from the first groove portion 41. The sealing material 5 that overflows from the first groove portion 41 is contained in the second groove portion 42. By assembling the housing 2 and base 4 in this manner, the outer periphery of the housing 10 becomes sealed around its entire circumference by the sealing material 5. Therefore, the electronic control device 1 can be made into a sealed structure.

The electronic control unit 1 according to this embodiment is intended to be mounted in the engine compartment. Therefore, to protect the printed circuit board 3 from saltwater and foreign matter, the housing 10 needs to be sealed, as described above. However, when the housing 10 is sealed, the pressure inside the housing 10 fluctuates due to temperature changes, etc. Therefore, if the internal pressure of the electronic control unit 1 becomes higher than the external pressure, a force acts to bend the housing 2 and base 4 constituting the housing 10 outward, causing the housing 2 and base 4 to deform. In this case, the amount of deformation of the housing 2 and base 4 is greatest at the center of the long side of the electronic control unit 1. Therefore, the sealing material 5 needs to have sufficient adhesive strength to withstand the deformation of the housing 2 and base 4. Furthermore, since the sealing material 5 generates gas during curing, this gas needs to be discharged to the outside of the electronic control unit 1.

The electronic control unit 1 according to this embodiment is designed to be 1.5 times larger in planar size than a typical electronic control unit, meaning it is considerably larger. Furthermore, the electronic control unit 1 is mounted in the engine compartment of a vehicle using a bracket (not shown). In this case, to grip the outer periphery of the electronic control unit 1 with the bracket, it is necessary to ensure an overlapping dimension L (Figure 3) of 10 mm or more between the first flange portion 11 and the second flange portion 12.

Furthermore, the mass of the electronic control unit 1 increases with its size. In such a large and massy electronic control unit 1, the area of the first opposing surface 31 of the first peripheral wall portion 14 and the area of the second opposing surface 32 of the second peripheral wall portion 15 increase due to the larger outer circumference. Therefore, when manufacturing the housing 2 and base 4, the flatness of the first opposing surface 31 and the second opposing surface 32 increases. Consequently, the first opposing surface 31 and the second opposing surface 32 have minute irregularities, as shown in Figure 4. Also, as mentioned above, as the electronic control unit 1 becomes larger, warping is more likely to occur in the housing 2 and base 4. As a result, when the housing 2 and base 4 are assembled, a gap is created between the first opposing surface 31 and the second opposing surface 32, as shown in Figure 4, making it difficult to electrically connect (conduct) the housing 2 and base 4 through contact between the opposing surfaces. The housing 2 and base 4 serve to protect the electronic components on the printed circuit board 3 from noise and static electricity. However, if the first opposing surface 31 and the second opposing surface 32 are not in contact, the electronic components may not be adequately protected from noise and static electricity. Furthermore, the sealing material 5 that seals the outer periphery of the housing 2 and base 4 is an insulating material and therefore does not contribute to the electrical connection between the housing 2 and base 4.

The connector 6 is mounted on the printed circuit board 3, electrically connected to the wiring pattern on the printed circuit board 3. Furthermore, when the printed circuit board 3 is mounted in the housing 2, the connector 6 is fitted into the opening 9 of the housing 2 via the connector seal material 51. The connector seal material 51 provides a waterproof function by sealing the mating portion between the opening 9 of the housing 2 and the connector 6. The connector 6 is mounted in the X direction shown in Figure 1, offset in the x1 direction from the center of the printed circuit board 3. Also, the connector 6 has a larger mass than other electronic components mounted on the printed circuit board 3. Therefore, the center of gravity of the printed circuit board 3 with three connectors 6 attached will be biased towards the x1 direction in the X direction.

Figure 5 is a side view of the electronic control device according to the first embodiment. Figure 6 is an enlarged plan view of a part of the base of the electronic control device according to the first embodiment. Figure 7 is a cross-sectional view taken along line A-A in Figure 6, and Figure 8 is a cross-sectional view taken along line B-B in Figure 6.

As shown in Figures 5 to 8, a protrusion 8 is interposed between the first flange portion 11 of the housing 2 and the second flange portion 12 of the base 4. The housing 2 and the base 4 are inclined at a relative angle θ due to the interposition of this protrusion 8. Note that in Figure 5, for ease of explanation, the protrusion of the protrusion 8 is exaggerated, and the inclination angle θ between the housing 2 and the base 4 is shown as larger.

The protrusions 8 are provided on the second opposing surface 32 of the second flange portion 12 of the base 4. Furthermore, one protrusion 8 is provided at each of the two corners of the base 4 that are not diagonally opposite each other. In other words, the protrusions 8 are positioned at both ends of one side of the base 4 that constitutes the housing 10. The protrusions 8, like the second peripheral wall portion 15, the first groove portion 41, and the second groove portion 42, are integrally formed with the base 4. For example, when the base 4 is manufactured by aluminum die-casting, the protrusions 8 can be formed integrally with the base 4 by forming recesses corresponding to the protrusions 8 in the molding die.

The protrusion 8 is formed in a cylindrical shape, protruding from the second opposing surface 32 of the second flange portion 12. The protrusion dimension Lh (Figure 7) of the protrusion 8, relative to the second opposing surface 32, is greater than the flatness of the second opposing surface 32. Therefore, even if minute irregularities exist on the second opposing surface 32, the protrusion 8 will protrude with a protrusion dimension Lh greater than the dimension of these irregularities. The protrusion dimension Lh of the protrusion 8 is preferably 0.2 mm or more and 0.7 mm or less.

Guide grooves 43 (Figure 6) are formed on both sides of the protrusion 8. The guide grooves 43 are connected to the second groove 42. Additionally, auxiliary grooves 44 (Figure 6) are formed at the corners of the second groove 42. The guide grooves 43 guide the sealant 5 overflowing from the first groove 41 to the second groove 42. The second opposing surface 32 forms a single plane except for the portions of the second groove 42, guide grooves 43, and auxiliary grooves 44.

The protrusion 8 is positioned on the x2 side, which is the side furthest from the center of gravity of the housing 2 in the X direction shown in Figure 5. Specifically, the protrusion 8 is positioned on the x2 edge of the base 4 in the X direction. As mentioned above, the center of gravity of the housing 2 is defined by the state in which the printed circuit board 3 with the connector 6 mounted is attached to the housing 2. In the state in which the printed circuit board 3 with the connector 6 mounted is attached to the housing 2, the mass balance of the housing 2 in the X direction is such that the mass ratio on the x1 side is greater than the mass ratio on the x2 side. Therefore, when assembling the housing 2 by placing it over the base 4, the load applied from the housing 2 to the base 4 by the total mass of the housing 2, including the printed circuit board 3 and the connector 6, is greater on the x1 side than on the x2 side.

Therefore, as shown in Figure 5, when the housing 2 is tilted at an angle θ by the protrusion 8 relative to the horizontally placed base 4, the load applied from the housing 2 to the base 4 increases at the end portion 20 of the housing 10 opposite the protrusion 8. In other words, at the end portion 20 of the housing 10, the first flange portion 11 of the housing 2 is pressed against the second flange portion 12 of the base 4 with considerable force.

In the electronic control device 1 according to the first embodiment described above, since a protrusion 8 is provided on the second opposing surface 32 of the base 4, when assembling the housing 2 and the base 4, the second opposing surface 32 of the housing 2 abuts against the tip of the protrusion 8. Therefore, the housing 2 is tilted at an angle θ with respect to the base 4. As a result, at the end edge 20 of the housing 10 located opposite the protrusion 8 in the X direction, the first opposing surface 31 of the first flange portion 11 and the second opposing surface 32 of the second flange portion 12 are in contact. This ensures reliable electrical conductivity between the housing 2 and the base 4 constituting the housing 10 through contact between the opposing surfaces 31 and 32. Therefore, the function of protecting the electronic components on the printed circuit board 3 housed within the housing 10 from noise, static electricity, etc., can be enhanced.

Furthermore, the protrusion 8 is integrally formed with the base 4. Therefore, providing the protrusion 8 on the housing 10 does not increase the number of parts or manufacturing steps. Also, the protrusion 8 is made of metal, just like the other parts of the base 4. Therefore, electrical connection can be established between the housing 2 and the base 4 via the protrusion 8.

Furthermore, the protrusion dimension Lh of the convex portion 8 is greater than the flatness of the second opposing surface 32 of the second flange portion 12. Therefore, when assembling the housing 2 and the base 4, the tip of the convex portion 8 can be reliably brought into contact (butted) with the second opposing surface 32 of the housing 2.

Furthermore, the protrusion 8 is positioned on the side furthest from the center of gravity of the housing 2 to which the printed circuit board 3 is attached. Therefore, at the edge portion 20 of the housing 10, the imbalance in the mass distribution of the housing 2 can be used to press the second flange portion 12 of the base 4 against the first flange portion 11 of the housing 2 with considerable force. This increases the contact pressure between the first opposing surface 31 and the second opposing surface 32 at the edge portion 20 of the housing 10, resulting in a more stable contact state.

Furthermore, the protrusions 8 are positioned at both ends of one side of the housing 10. Therefore, on the end side 20 of the housing 10 opposite the protrusions 8, the first opposing surface 31 and the second opposing surface 32 can be brought into contact along the entire length of the end side 20.

Furthermore, by adopting a configuration with a protrusion 8, a gap is formed between the first opposing surface 31 of the first flange portion 11 and the second opposing surface 32 of the second flange portion 12 due to the relative inclination of the housing 2 and the base 4 described above. This makes it easier for the gas generated during the curing of the sealing material 5 to escape to the outside of the electronic control device 1.

<Second Embodiment>
Next, an electronic control device according to the second embodiment will be described.
The electronic control device according to the second embodiment differs from the electronic control device according to the first embodiment in the configuration of the base (second housing member), which is one of the components of the metal housing.

Figure 9 is an enlarged view of a part of the base of the electronic control device according to the second embodiment. Figure 10 is a cross-sectional view taken along line C-C in Figure 9.
As shown in Figures 9 and 10, the second opposing surface 32a along the long side of the base 4 protrudes upward by a predetermined projection dimension Lh compared to the other second opposing surfaces 32. In other words, the second opposing surface 32a constitutes a protrusion that extends from the second opposing surfaces 32. The second opposing surface 32a is formed to be continuous along one side of the housing 10 (base 4).

Furthermore, the second opposing surface 32a is integrally formed with the base 4, similar to the protrusion 8 in the first embodiment. Since the second opposing surface 32a is formed from the same metal as the base 4 (for example, aluminum), it is electrically conductive. The protrusion dimension Lh of the second opposing surface 32a is set to be the same as the protrusion dimension Lh of the protrusion 8 in the first embodiment.

In the second embodiment, the second opposing surface 32a of the base 4 is made to protrude more than the other second opposing surfaces 32, forming a convex portion. Therefore, for the same reasons as in the first embodiment, the housing 2 and the base 4 can be reliably electrically connected by contact between the opposing surfaces 31 and 32. Furthermore, the second opposing surface 32a is formed to be continuous along one side of the housing 10. Therefore, on the side where the second opposing surface 32a as a convex portion is formed, an electrical connection point between the first opposing surface 31 and the second opposing surface 32 can be secured along the entire longitudinal direction of the second opposing surface 32a. Also, the second opposing surface 32a is integrally formed with the base 4. Therefore, similar to the first embodiment, the housing 2 and the base 4 can be electrically connected without increasing the number of parts or manufacturing man-hours. Other effects are omitted from the explanation as they overlap with those of the first embodiment.

In the second embodiment, the second opposing surface 32a along the long side of the base 4 was made to protrude more than the other second opposing surfaces 32 to form a convex portion; however, the present invention is not limited to this. For example, as another example of the C-C cross-sectional view in Figure 9, as shown in Figure 11, the second opposing surface 32b along the short side of the base 4 may be made to protrude more than the other second opposing surfaces 32 to form a convex portion. Also, although not shown, the second opposing surface 32 sandwiched between the two guide grooves 43 may be made to protrude more than the other second opposing surfaces 32 to form a convex portion.

Furthermore, protrusions may be formed at both ends of the second opposing surface 32 along the long or short side of the base 4. Alternatively, a protrusion may be formed at only one location (preferably in the middle) of the second opposing surface 32 along the long or short side of the base 4. This also applies to the protrusion 8 in the first embodiment described above, and to the embodiments described later.

<Third Embodiment>
Next, an electronic control device according to the third embodiment will be described.
The electronic control device according to the third embodiment differs from the electronic control device according to the first embodiment in the configuration of the base (second housing member), which is one of the components of the metal housing.

Figure 12 is an enlarged view of a part of the base of the electronic control device according to the third embodiment. Figure 13 is a cross-sectional view taken along line D-D in Figure 12.
As shown in Figures 12 and 13, tape material 85 is provided as a protrusion at the corner of the base 4. The tape material 85 is attached to the second opposing surface 32 sandwiched between two guide grooves 43. When the housing 2 and the base 4 are assembled, the tape material 85 is attached to the first opposing surface 31 of the housing 2.

The tape material 85 is made of a conductive tape, such as a conductive double-sided tape. The conductive double-sided tape is, for example, a double-sided tape using an adhesive containing a conductive filler such as carbon powder. In a configuration where the tape material 85 is attached to the second opposing surface 32, the protrusion dimension Lh (Figure 13) of the tape material 85 relative to the second opposing surface 32 corresponds to the thickness dimension of the tape material 85.

In the third embodiment, a protrusion is formed by a tape material 85 attached to the second opposing surface 32 of the base 4. Therefore, for the same reasons as in the first embodiment, the housing 2 and the base 4 can be reliably electrically connected by contact between the opposing surfaces 31 and 32.

Furthermore, the tape material 85 is a separate component from the base 4. Therefore, the same effects as in the first embodiment can be obtained by reusing an existing (conventional) base 4 that does not have a protrusion. Also, since the tape material 85 is conductive, the housing 2 and the base 4 can be electrically connected via the tape material 85. In addition, since the tape material 85 is made of double-sided tape, the housing 2 and the base 4 can be temporarily fixed in place until the sealant 5 hardens.
Other effects will be omitted from the explanation as they overlap with those of the first embodiment.

<Fourth Embodiment>
Next, an electronic control device according to the fourth embodiment will be described.
The electronic control device according to the fourth embodiment differs from the electronic control device according to the first embodiment in the specific means for forming the protrusions.
Figure 14 is an enlarged longitudinal cross-sectional view of the main part of the electronic control device according to the fourth embodiment.
As shown in Figure 14, a portion 5a of the sealing material 5 protrudes between the first opposing surface 31 of the housing 2 and the second opposing surface 32 of the base 4. The portion 5a of the sealing material 5 is formed to protrude from the first opposing surface 31, for example, when the first opposing surface 31 is used as a reference. In other words, in the fourth embodiment, the protrusion is formed by the portion 5a of the sealing material 5.

One method for forming a protrusion using a portion 5a of the sealant 5 is, for example, when applying the sealant 5 to the first groove 41 of the base 4, a larger amount of sealant 5 should be applied to the area where the protrusion is intended, so that it overflows from the first groove 41. This causes a portion 5a of the sealant 5 to overflow from the first groove 41 when the lower end 14a of the first peripheral wall 14 is embedded in the second peripheral wall 15. At this time, the thickness t of the portion 5a of the sealant 5 determines the protruding dimension of the protrusion. Therefore, the pressing force of the housing 2 against the base 4 should be adjusted, for example, so that a portion 5a of the sealant 5 remains between the first opposing surface 31 and the second opposing surface 32 with an appropriate thickness t. After the sealant 5 hardens, the protrusion can be formed using the portion 5a of the sealant 5.

In the fourth embodiment, a protrusion is formed by a portion 5a of the sealing material 5. For the same reasons as in the first embodiment, the housing 2 and the base 4 can be reliably electrically connected by contact between the opposing surfaces 31 and 32. Furthermore, the sealing material 5 is a separate component from the base 4. For this reason, the same effects as in the first embodiment can be obtained by reusing an existing (conventional) base 4 that does not have a protrusion.
Other effects will be omitted from the explanation as they overlap with those of the first embodiment.

<Examples of variations, etc.>
It should be noted that the present invention is not limited to the embodiments described above, and includes various modifications. For example, although the embodiments described above are explained in detail to facilitate understanding of the present invention, the present invention is not necessarily limited to having all the configurations described in the embodiments described above. Furthermore, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment. It is also possible to add the configuration of another embodiment to the configuration of one embodiment. In addition, it is possible to delete a part of the configuration of each embodiment, add other configurations, or replace other configurations.

For example, in the embodiments described above, a protrusion is formed on the second opposing surface 32 of the base 4, but the present invention is not limited to this, and a protrusion may also be formed on the first opposing surface 31 of the housing 2. Furthermore, protrusions may be formed on both the first opposing surface 31 and the second opposing surface 32. Also, the protrusion may be provided at only one location on any side of the housing 10 (preferably in the middle), at multiple locations along any side, or continuously (linearly) along any side.

1…Electronic control unit, 2…Housing (first housing component), 3…Printed circuit board, 4…Base (second housing component), 5…Sealing material, 5a…Part (protrusion), 8…Protrusion, 10…Housing, 11…First flange portion, 12…Second flange portion, 31…First opposing surface, 32…Second opposing surface, 32a, 32b…Second opposing surface (protrusion), 85…Tape material (protrusion)

Claims (6)

An electronic control device comprising a printed circuit board on which electronic components are mounted, and a metal housing that houses the printed circuit board,
The housing comprises a first housing member having a first flange portion on which a first opposing surface is formed, and a second housing member having a second flange portion on which a second opposing surface is formed, which is positioned opposite the first opposing surface.
A convex portion is formed on at least one of the first opposing surface and the second opposing surface, such that it protrudes from the opposing surface.
The aforementioned housing is formed in a rectangular shape in plan view,
The aforementioned protrusion is formed to be continuous along one side of the housing,
The aforementioned protrusion is attached to the first housing member and/or the second housing member.
Electronic control unit. The electronic control device according to claim 1, wherein the protruding dimension of the convex portion is greater than the flatness of the first opposing surface and/or the flatness of the second opposing surface. The printed circuit board is attached to the first housing member.
The center of gravity of the first housing member to which the printed circuit board is attached is biased to one side in a predetermined direction.
The electronic control device according to claim 1, wherein the protrusion is located on the side furthest from the center of gravity of the first housing member in the predetermined direction. The aforementioned housing is formed in a rectangular shape in plan view,
The electronic control device according to claim 1, wherein the protrusions are arranged at both ends of one side of the housing. The electronic control device according to claim 1 , wherein the convex portion is conductive. The electronic control device according to claim 1 or 5 , wherein the protrusion is made of double-sided tape.