Electronic control device

Abstract

Provided is an electronic control device 1 comprising: a first housing 20 and a second housing 30 that house a circuit board (10); a glass coating layer 31a formed in at least one of the first housing 20 and the second housing 30; and a seal member (40) provided between the first housing 20 and the second housing 30. The glass coating layer 31a is disposed so as to be in contact with the seal member (40). As a result, the present invention can provide a compact electronic control device with air tightness reliably satisfying strict requirements for salt damage prevention.

Description

Electronic control unit

[0001] The present disclosure relates to electronic control devices.

[0002] Automotive electronic control devices are required to have strict environmental resistance specifications against corrosion and degradation, as well as a long lifespan. Long life is particularly required in environments where salt damage occurs, and a seal structure that prevents the progression of crevice corrosion is important. Furthermore, as vehicles become more sophisticated and functionally integrated, the size of electronic control devices is increasing, while inexpensive, high-quality products are required. Furthermore, pressure differences can occur within electronic control devices due to altitude changes during air transport, etc., and a seal structure with extremely high pressure resistance of 50 kPa to 85 kPa may be required.

[0003] Patent technology relating to a sealing structure is disclosed in Patent Document 1. Patent Document 1 describes a storage case having a hollow case member and a lid member that covers the hollow portion of the case member, in which a bonding thin film made of a silicone-based thin film or a carbon-based thin film is formed on the open end surface of the case member, and the sealing member and the case member are bonded via this bonding thin film, thereby ensuring the sealing structure of the storage case even in harsh environments where seawater (salt water) or the like may adhere.

[0004] JP 2014-86682 A

[0005] As electronic control devices become more sophisticated, integrated, and larger, the number of parts that need to be sealed tends to increase. However, in order to control costs, it is necessary to reduce the amount of sealing material used.

[0006] On the other hand, due to recent abnormal weather and other factors, it is becoming more common for cars to become submerged in water, which has led to higher requirements for seals.

[0007] Furthermore, to contribute to the fuel efficiency improvements required for automobiles, the housings of electronic control units must be made thinner and lighter, despite being larger in size. This requires molding technology for housings that maintain thinness while suppressing deformation. In addition, because electronic components, not just aluminum electrolytic capacitors, need to be made thinner, the waterproof sealing structure also needs to be made thinner.

[0008] In this situation, there is a demand for low-cost adhesive technology that provides high adhesive strength.

[0009] As a result of extensive research into extending the service life in environments where the sealant comes into contact with salt water, etc., the inventors have found that there is room for improvement in that an airtight structure created simply by applying a sealant to a metal surface relies on adhesion through hydrogen bonding between the OH groups present on the metal surface and the OH groups of the sealant, but if the OH groups present on the metal surface are not stable, sufficient salt damage cannot be prevented, and leak defects may occur.

[0010] Patent Document 1 describes improving the bonding strength by bonding a bonding thin film, such as a silicone-based thin film or a carbon-based thin film, to a sealing member, but there is still room for improvement in obtaining sufficient bonding strength while realizing a low profile and low cost.

[0011] An object of the present disclosure is to provide a compact electronic control device that has highly reliable airtightness that satisfies increasingly strict requirements for preventing salt damage.

[0012] The electronic control device of the present disclosure comprises a first housing and a second housing that house a circuit board, a glass coating layer formed on at least one of the first housing and the second housing, and a sealing member provided between the first housing and the second housing, and the glass coating layer is arranged so as to be in contact with the sealing member.

[0013] According to the present disclosure, it is possible to provide a compact electronic control device that has highly reliable airtightness that meets increasingly stringent requirements for preventing salt damage. Problems, configurations, and effects other than those described above will become clear from the description of the following examples.

[0014] 5 is an exploded perspective view showing an electronic control device according to a first embodiment; FIG. 6 is a cross-sectional view of a main part of the electronic control device according to the first embodiment; FIG. 7 is a schematic cross-sectional view showing the chemical structure of a steel sheet surface before bonding in the first embodiment; FIG. 8 is a schematic cross-sectional view showing the chemical structure of a steel sheet surface after bonding in the first embodiment; FIG. 9 is a schematic cross-sectional view showing a glass coating layer according to the first embodiment; FIG. 10 is a table showing an example of measurement results of functional groups at each position on the glass coating layer of FIG. 5; FIG. 11 is a graph showing the relationship between Si—O peak height and adhesive strength; FIG. 12 is a graph showing the relationship between C—H peak height and adhesive strength; FIG. 13 is a graph showing the relationship between O—H peak height and adhesive strength; FIG. 14 is a graph showing the relationship between the ratio of C—H peak to Si—O peak (C—H / Si—O relative ratio) and adhesive strength; FIG. 15 is a table showing critical values ​​of peak heights of each functional group; FIG. 16 is a graph showing an example of analysis results of a steel sheet surface before bonding in the first embodiment; FIG. 17 is a schematic cross-sectional view showing the chemical structure of a steel sheet surface of a comparative example before bonding; FIG. 18 is a schematic cross-sectional view showing the chemical structure of a steel sheet surface of a comparative example after bonding; FIG. 19 is an exploded perspective view showing an electronic control device according to a second embodiment; Fig. 10 is a cross-sectional view of a main part of an electronic control device according to a second embodiment; Fig. 11 is a cross-sectional view of a main part of an electronic control device according to a third embodiment; Fig. 12 is a cross-sectional view of a main part of an electronic control device according to a fourth embodiment; Fig. 13 is a cross-sectional view of a main part of an electronic control device according to a fifth embodiment; and Fig. 14 is a cross-sectional view of a main part of an electronic control device according to

[0015] Electronic control devices according to first to sixth embodiments of the present disclosure will be described below with reference to the drawings. In the drawings used in this specification, identical or similar reference numerals are used to designate identical or corresponding components, and repeated description of these components may be omitted.

[0016] First Embodiment A first embodiment of an electronic control device according to the present disclosure will be described with reference to FIGS. 1 to 7. FIG.

[0017] First, the overall configuration of the electronic control unit will be described with reference to FIG.

[0018] Fig. 1 is an exploded perspective view showing an electronic control device according to a first embodiment. For convenience of illustration, electronic components mounted on a board are omitted from Fig. 1.

[0019] 1, the electronic control device 1 is composed of a printed wiring board 10 on which electronic components and the like are mounted, a first housing 20 (case), a second housing 30 (cover), a connector 60, sealing materials 40 and 41, screws 50 and 51, etc. Note that the printed wiring board 10 is an example of a circuit board, and the contents of the present disclosure are not limited to printed wiring boards. Here, the sealing materials 40 and 41 are also referred to as "sealing members."

[0020] The first housing 20, together with the second housing 30, houses the printed wiring board 10 and protects the printed wiring board 10, on which electronic components are mounted, from water, foreign matter, etc. The first housing 20 is preferably made of metal, and aluminum is preferable, in order to dissipate heat generated by the electronic components and to shield noise. In particular, when the electronic control unit 1 is used for a direct injection engine, a shielding effect is required.

[0021] The first housing 20 is formed by aluminum die-casting using a mold. In the case of an electronic control device composed of electronic components that do not require heat dissipation or shielding, the material of the first housing 20 may be resin. In the case of resin, the first housing 20 is formed by injection molding.

[0022] The second housing 30 is fixed opposite the first housing 20, and an internal space 11 (see FIG. 2 ) is formed between the first housing 20 and the second housing 30. A sealant 40 is sandwiched between the flange portion of the first housing 20 and the flange portion 31 of the second housing 30, so that the internal space 11 is sealed.

[0023] The external dimensions of the electronic control unit 1 are preferably approximately 240 mm x 160 mm, which is relatively large compared to other electronic control units arranged in the engine compartment, and the shape of the top surface is approximately rectangular. Conventional electronic control units are usually approximately 160 mm x 160 mm in size, and the electronic control unit 1 of this embodiment is at least 1.5 times the size of such conventional units.

[0024] The first housing 20 has a through opening 21. The opening 21 is configured so that the connector 60 can pass through. The pressure inside the first housing 20 changes due to changes in altitude, temperature, and other factors during transportation of the vehicle and in the environment in which it is used. For this reason, the shape of the center of the first housing 20 changes the most. The center of the first housing 20 bulges outward when the internal pressure is high, and dents inward when the internal pressure is low. Therefore, it is preferable that the opening 21 be positioned closer to the periphery of the first housing 20 as viewed from the center.

[0025] Heat dissipation fins 25 are provided in the portions of the first housing 20 where no openings 21 are provided. The direction of the heat dissipation fins 25 is parallel to the long sides of the first housing 20 in Fig. 1. However, the direction of the heat dissipation fins 25 is not limited to this drawing, and they may be parallel to the short sides of the first housing 20. It is desirable that the direction of the heat dissipation fins 25 be parallel to the flow of molten metal from the gate in aluminum die casting.

[0026] There are two types of gate locations in aluminum die casting.

[0027] First, the short side of the rectangular first housing 20 and the opposite side of the opening 21 is selected so as to be parallel to the longitudinal direction of the connector 60 and the heat dissipation fin 25, and the overflow position is set on the surface of the short side opposite the gate or on the side surface.

[0028] Furthermore, the second gate is located on the long side of the rectangular first housing 20, with an overflow on the opposite long side. For large, rectangular shapes, molding must be completed within the time it takes for the aluminum to solidify. Therefore, the second gate location improves melt flow and reduces casting defects. Improved melt flow reduces air entrapment, eliminating aluminum die-cast defects such as porosity and weld marks, reducing the amount of aluminum flowing to the overflow, and enabling lower-cost molding. Poor melt flow and molding defects such as porosity and weld marks can reduce thermal conductivity and cause cracks, potentially affecting strength and appearance. Furthermore, the amount of deformation of the housing after molding increases, making it difficult to maintain flatness. In this case, the airtightness of the sealing material is reduced, so it is desirable to use a method that improves melt flow.

[0029] The first housing 20 is provided with a plurality of pedestals for fixing the printed wiring board 10. For example, pedestals are provided that are tapped for fastening the screws 50 and pedestals with a surface precision to which the heat dissipation adhesive 42 is applied. Furthermore, the first housing 20 is also provided with pedestals that are fixed to the second housing 30 via screws 51.

[0030] The sealing material 41 is provided for waterproofing purposes, and in order to protect against foreign matter such as salt water as required by the environmental specifications of the engine room, a silicone adhesive that is heat-resistant, water-resistant, chemical-resistant, and flexible is suitable.

[0031] The sealant 40 is provided for waterproofing purposes and is a member that seals the internal space formed by the first housing 20 and the second housing 30. As with the sealant 41, a silicone adhesive is suitable for this. In particular, the long sides of the first housing 20 are most deformed at the center because, when pressure changes within the first housing 20 due to temperature changes, internal pressure is applied to the first housing 20, causing the center of the first housing 20 to bend in the normal direction (upper side in FIG. 1 ). Therefore, the sealant 40 can have adhesive strength that can withstand deformation.

[0032] The second housing 30 has holes at its four corners through which screws 51 for fastening the first housing 20 and the second housing 30 pass. The second housing 30 and the first housing 20 are fastened together with the sealing material 40 by the screws 51. It is desirable to place the screws 51 at the four corners so that the application path of the sealing material 40 does not become complicated. The electronic control device 1 of this embodiment is approximately 1.5 times larger in size than conventional electronic control devices, so a thin material is selected for the second housing 30, but strength is ensured by providing ribs, dimples, steps, etc.

[0033] Electronic components are mounted on the printed wiring board 10 using a conductive alloy such as solder. Mounting can also be done on both sides. The electronic components include passive components such as resistors and capacitors, and active components such as semiconductors, and are mounted on the printed wiring board 10 by surface mounting or insertion mounting. It is desirable to use electronic components with long life that can withstand the environment in an automobile engine compartment.

[0034] To increase the packaging density of electronic component packages, high-density BGAs (Ball Grid Arrays) and QFNs (Quad For Non-Lead Packages) are used, along with QFPs (Quad Flat Packages) with extended lead terminals. BGAs have hemispherical electrodes formed by the surface tension of a conductive alloy attached to terminals arranged in a grid pattern on the bottom of the package, and are bonded to the printed wiring board 10 by reflow soldering. QFNs have shorter terminals than QFPs and are connected to the printed wiring board 10 by a conductive alloy. If the printed wiring board 10 deforms significantly, the joints are susceptible to stress, so it is necessary to suppress the amount of deformation of the printed wiring board 10.

[0035] The printed wiring board 10 is fixed to a tapped base of the first housing 20 with a plurality of screws 50. At this time, the printed wiring board 10 is fixed so that a heat dissipation adhesive 42 is sandwiched between the printed wiring board 10 and the base of the first housing 20, which has a high surface accuracy. With this configuration, heat generated by the electronic components is conducted to the base through the vias of the printed wiring board 10 and dissipated from the surface of the first housing 20, including the heat dissipation fins 25.

[0036] The height position of the printed wiring board 10 is preferably centered between the first housing 20 and the second housing 30. Preventing the printed wiring board 10 from leaning to one side limits the height of the mounted electronic components, making it possible to avoid the inability to place tall electronic components on both sides. Furthermore, by positioning the printed wiring board 10 heightwise in the center between the first housing 20 and the second housing 30, the electronic control unit 1 can be made low-profile. By making the electronic control unit 1 low-profile, it becomes easier to secure space when mounting it in an engine compartment, and it becomes easier to receive air for cooling.

[0037] As described above, the electronic control device 1 of this embodiment is relatively large in size among electronic control devices that are preferably placed in the engine compartment, so four to seven screws 50 are used to fix the printed wiring board 10 to the first housing 20 via the heat dissipation adhesive 42.

[0038] The screws 50 are preferably positioned with equal distances between each other, taking into consideration the four corners of the printed wiring board 10 and the placement of electronic components. In particular, distortion occurs in the printed wiring board 10 near the screws 50, so it is desirable to position the screws 50 in a way that does not cause distortion in the connector 60 or the joints formed of the conductive alloy of the BGA or QFN, and positioning them too close to each other is avoided.

[0039] The screws 50 also function as case earths, and the GND wiring pattern of the printed wiring board 10 is electrically connected to the first housing 20 via the screws 50. It is desirable that the case earths be located at the four corners of the printed wiring board 10 in terms of routing the wiring pattern of the printed wiring board 10. Here, GND stands for ground.

[0040] The printed wiring board 10 is preferably a glass epoxy board made by layering glass fiber cloth and impregnating it with epoxy resin, a multilayer board in which insulators and patterns are stacked, and a multilayer board with 4 to 8 layers is used because high-density packaging is required. Also, a penetrating board in which wiring is performed between layers using through-holes or a build-up board using a build-up method are preferable.

[0041] The heat dissipation adhesive 42 transfers heat from the electronic components to the base of the first housing 20, which has a high surface precision, via the vias in the printed wiring board 10. The thinner the thickness of the heat dissipation adhesive 42, the easier it is to transfer heat. If the first housing 20 deforms in the normal direction (upward in FIG. 1 ), the clearance with the printed wiring board 10 increases, resulting in a decrease in heat dissipation performance. For this reason, it is effective to suppress deformation of the first housing 20. Heat-generating electronic components that require heat dissipation are placed under the heat dissipation fins 25.

[0042] The connector 60 is composed of a housing 61 , terminals 63 and a potting material (not shown in the drawings), and is connected to the printed wiring board 10 .

[0043] The terminals 63 are press-formed from a copper-based material with high thermal conductivity. The terminals 63 are linear and have a flattened tip to facilitate insertion into a connector on the harness side or a through-hole in the printed wiring board 10. The housing 61 is formed from resin by injection molding, and the terminals 63 are press-fitted into the housing 61. Alternatively, the housing 61, including the terminals 63, may be insert-molded. A potting material is used to create an airtight seal, as there is a gap between the housing 61 and the terminals 63.

[0044] The size of the connector 60 depends on the number of poles and width of the terminals 63. The terminals 63 have both signal terminals and power terminals with different current capacities, with a total of approximately 60 to 80 poles. The power terminals are wider. The terminals 63 are connected to the through-holes in the printed wiring board 10 using a conductive alloy (not shown) such as solder. Alternatively, press-fit terminals (not shown) may be used for mechanical and electrical connection.

[0045] In the first embodiment, there are three connectors 60, but the number is not limited to three and may be three or more. Accordingly, there may be three or more openings 21 in the first housing. By arranging the middle connector 60 on the outermost side, the area for mounting electronic components can be increased. Furthermore, the wiring pattern of the printed wiring board 10 does not become high density, and overlapping of the pattern wiring can be avoided.

[0046] In the assembly of the connector 60 of this embodiment, the connector 60 is connected to the outside of the opening 21 of the first housing 20 via the sealant 41, but it may also be connected to the printed wiring board 10 first, and then connected to the inner surface side of the opening 21 of the first housing 20 via the sealant 41. Connecting the connector 60 from the outside of the opening 21 of the first housing 20 has the advantage that the seal structure of the connector 60 can be made smaller.

[0047] Next, a method for connecting the connector 60 to the first housing 20 will be described.

[0048] A sealant 41 is applied around the bottom edge of the housing 61 of the connector 60 and hardens to form a seal. When the area around the connector 60 in the first housing 20 expands and deforms in the normal direction due to heat or pressure inside the first housing 20, the sealant 41 functions as a buffer, but because the clearance is small, the connector 60 also deforms at the same time. The deformation of the connector 60 also affects the terminals 63, and the deformation is simultaneously transmitted to the printed wiring board 10 via the conductive adhesive.

[0049] FIG. 2 is a cross-sectional view of a main part of the electronic control device according to this embodiment.

[0050] As shown in the figure, a glass coating layer 31a is provided on the underside of the flange portion 31 of the second housing 30. A sealant 40 is sandwiched between this glass coating layer 31a and the flange portion 22 of the first housing 20. The width of the sealant 40 is 4 mm. Here, the width of the sealant 40 refers to the dimension between the outer peripheral end and inner peripheral end of the flange portion 31 of the sealant 40. In other words, this width is equal to the distance from the left end to the right end of the sealant 40 in the figure.

[0051] Furthermore, if the second housing 30 is made of pre-plated steel sheet, the cut surface during molding will not be plated, so it is desirable to protect the end 33 with a glass coating layer 33a or the like to prevent corrosion of the steel sheet. By providing the glass coating layer 31a, even if the sealing material 40 happens to absorb water, the glass coating layer 31a can prevent the flange portion 31 from coming into direct contact with water, thereby preventing corrosion of the flange portion 31.

[0052] The material of the second housing 30, which serves as the cover, is preferably an iron-based or aluminum-based plate material, but may also be resin or aluminum die-cast. Metal is more preferable from the viewpoint of EMC.

[0053] For example, the second housing 30 is preferably made of a steel plate having a uniform thickness and formed by press forming. In the case of a steel plate, it is more preferable that the steel plate is plated. The plating is preferably made of zinc, aluminum, magnesium, or the like, which has high corrosion resistance in the engine room environment.

[0054] It is preferable that the surface of the glass coating layer 31 a is formed parallel to the first housing 20 or the second housing 30 .

[0055] FIG. 3 is a schematic cross-sectional view showing the chemical structure of the surface of a steel sheet before bonding in this embodiment.

[0056] As shown in the figure, a glass coating layer 31a is formed on the surface of a flange portion 31 made of a steel plate. The surface of the glass coating layer 31a contains CH 3 as well as OH groups. ３ There is a group.

[0057] FIG. 4 is a schematic cross-sectional view showing the chemical structure of the surface of the steel sheet after bonding in this embodiment.

[0058] As shown in the figure, the surface of the applied and hardened sealing material 40 contains CH groups as well as OH groups. ３ There is a group.

[0059] When the glass coating layer 31a and the sealing material 40 are bonded together, the SiO groups of the glass coating layer 31a react with the SiO groups of the sealing material 40 to form covalent bonds. Also, the OH groups on the surface of the glass coating layer 31a and the OH groups on the surface of the sealing material 40 form hydrogen bonds. Furthermore, the CH ３ CH between the substrate and the surface of the sealing material 40 ３ The groups are bonded by intermolecular forces (van der Waals forces).

[0060] In this figure, the solid line represents a single bond connecting the glass coating layer 31a and the sealing material 40, and O represents a covalent bond. The dashed line connecting O and H of the OH group represents a hydrogen bond.３ When groups are adjacent to each other, an attractive force occurs due to an intermolecular force. This diagram conceptually shows the forces acting between atoms and molecules, and it goes without saying that the types of atoms or molecules that generate this force are not limited to these. For example, CH ３ As functional groups other than the group (methyl group), ２ H ５ group (ethyl group), C ３ H ７ When a group such as a propyl group is present, an attractive force due to an intermolecular force occurs, similar to the case of a methyl group, and contributes to adhesive strength.

[0061] The glass coating layer 31a has a larger number of SiO and OH groups than the surface of a conventional bare housing, resulting in stronger hydrogen bonds and covalent bonds than before. In addition, the glass coating layer 31a is newly provided with intermolecular forces that provide water resistance, which gives the bonded interface hydrophobicity compared to conventional structures, improving waterproofing and allowing the glass coating layer 31a to maintain high adhesive strength even after salt damage testing.

[0062] FIG. 5 is a schematic cross-sectional view showing the glass coating layer in this embodiment.

[0063] As shown in this figure, a glass coating layer 31a having a predetermined dimension is formed on the surface of the flange portion 31. The cross section of the glass coating layer 31a in the width direction shown in this figure has a mountain-like shape with a flat top portion. The thickness of the glass coating layer 31a is represented by t.

[0064] In this figure, the central portion of the glass coating layer 31a is indicated by the reference numeral 1, and positions at equal intervals of 2 mm are indicated by the reference numerals 2 to 5. The positions indicated by the reference numerals 1 and 2 correspond to the flat top portion of the glass coating layer 31a. The positions indicated by the reference numerals 3 to 5 correspond to the slope of the glass coating layer 31a. The area between the reference numeral 2 on the left side of the figure and the reference numeral 2 on the right side of the figure is close to the center of the glass coating process, so the layer thickness t is stable and the functional group content is also stable. This area indicates the highly reliable adhesive region described below.

[0065] FIG. 6A is a table showing an example of the measurement results of functional groups at each position on the glass coating layer of FIG.

[0066] In FIG. 6A, Si—O bonds and C—H bonds (800 cm －１ ), [C-H bond (800cm －１ ) / Si—O bond] and O—H bond values ​​are shown. The values ​​shown in this figure are peak heights calculated by measuring absorbance by Fourier transform infrared spectroscopy (FTIR) using the ATR method and correcting the background of the absorbance obtained. Here, ATR is an abbreviation for Attenuated Total Reflection.

[0067] Next, the relationship between the peak height of each functional group and the adhesive strength will be described.

[0068] FIG. 6B is a graph showing the relationship between Si—O peak height and adhesive strength.

[0069] FIG. 6C is a graph showing the relationship between C—H peak height and adhesive strength.

[0070] FIG. 6D is a graph showing the relationship between O—H peak height and adhesive strength.

[0071] FIG. 6E is a graph showing the relationship between the ratio of the C—H peak to the Si—O peak (relative ratio of C—H / Si—O) and the adhesive strength.

[0072] In the graphs of Figures 6B to 6D, the horizontal axis represents the peak height of each functional group, and the vertical axis represents adhesive strength. The horizontal axis of the graph of Figure 6E represents the ratio of the C-H peak height to the Si-O peak height (C-H / Si-O relative ratio). In these figures, the evaluation standard adhesive strength of 1.0 MPa is indicated by a dashed line.

[0073] 6B to 6E, adhesive strengths equal to or greater than the standard are indicated by an O mark, and adhesive strengths below the standard are indicated by a △ mark. The lower and upper limits of each peak height are indicated by dashed lines.

[0074] The peak height value of each functional group was obtained by measuring local absorbance by FTIR (ATR method), plotting the logarithm of absorbance on the vertical axis, and correcting for background. The adhesive strength was measured when a sample in which a sealing material was applied between two steel plates provided with a glass coating layer was pulled using a tensile tester and the two steel plates separated.

[0075] Figure 6F is a table summarizing the functional group conditions for reliable adhesion from Figures 6B to 6E, i.e., the critical peak height values ​​for each functional group.

[0076] As shown in FIG. 6F, the glass coating layer 31a has a peak height of 0.03 or more for SiO bonds and 0.03 or more for CH bonds. ３ When the CH bond of the group is 0.003 to 0.007, the OH bond is 0.005 or more, and the C—H / Si—O relative ratio is 0.05 to 0.24, the highly reliable adhesive region is obtained.

[0077] Furthermore, the highly reliable adhesive region must have a glass coating layer thickness t of 50 nm or more and 300 nm or less, as measured by X-ray fluorescence analysis (XRF). If t is less than 50 nm, corrosion resistance is insufficient, and airtightness cannot be achieved after corrosion in a salt damage test or the like. If t exceeds 300 nm, the bonding strength within the glass coating layer decreases, the strength of the glass coating layer decreases, interlayer fracture occurs, and sufficient adhesive strength cannot be obtained. Therefore, the highly reliable adhesive region of the glass coating layer must have t of 50 nm or more and 300 nm or less. That is, it must satisfy the condition 50≦t≦300 (unit: nm).

[0078] In addition, in the electronic control device of the present disclosure, the pressure-receiving area of ​​the cover due to the change in internal pressure is 0.03 m ２ The required internal pressure is a maximum of 85 kPa. Therefore, the load that the sealing material receives due to the internal pressure is 2550 N, which is the product of the pressure-receiving area and the internal pressure.

[0079] When the width of the sealing material 40 is 4 mm, the adhesive area of ​​the sealing material 40 is 0.0027 m ２ The minimum tensile adhesive strength of the silicone adhesive after immersion in water is approximately 1.0 MPa. Therefore, the adhesive area is 0.0027 m ２The adhesive strength at this point is 2700N.

[0080] Therefore, the load (2550 N) that the sealing material receives due to changes in internal pressure is smaller than the adhesive strength (2700 N) in the sealing area, and taking into account variations in adhesive application, the seal width that satisfies the adhesive area required to maintain airtightness when internal pressure changes must be at least 4 mm or more.

[0081] Therefore, in consideration of the cost and the process cycle time, the OH group and the CH ３ By forming a highly reliable adhesive region that contains a sufficient amount of groups and setting the width of sealant 40 corresponding to the highly reliable adhesive region of glass coating layer 31a to at least 4 mm as shown in Fig. 2, peeling and cohesive failure of glass coating layer 31a can be prevented, and airtightness, water resistance, and salt damage resistance can be satisfied. That is, the width of sealant 40 is 4 mm or more, with the width of glass coating layer 31a being substantially the upper limit.

[0082] The glass coating layer 31a is preferably formed as a surface treatment film by a plasma glass coating process that allows for high adhesion to the flange portion 31. The plasma glass coating process is preferably performed using a plasma treatment equipment (Plasmatreat: PTU1212) equipped with a nozzle (Plasmatreat: PFW10), a plasma control unit (Plasmatreat: PCU), and a plasma generator (Plasmatreat: FG5002S), and using a material containing an organic substance such as hexamethyldisiloxane or hexamethyldisilazane as a precursor. ３ A glass coating layer 31a having a group or the like can be formed.

[0083] The precursor is not limited to the above, and may be any precursor in which the terminal of the Si group is CH ３ Anything that has a functional group in the carbon chain, such as a base, can be used.

[0084] Furthermore, the glass coating layer 31a may be formed by a method other than plasma glass coating, as long as it can be highly adhered to the flange portion 31. It is more preferable that the glass coating layer 31a is formed directly on the flange portion 31 with an adhesive strength of 1.0 MPa or more. This value of 1.0 MPa corresponds to the cohesive failure strength of commonly used silicone-based sealants.

[0085] In other words, it is preferable that the adhesive strength between the flange portion 31 and the glass coating layer 31a is equal to or greater than the cohesive failure strength of the silicone-based sealant. Therefore, as long as this relationship is satisfied, there are no numerical limitations.

[0086] 7 is a graph showing an example of the analysis results of the steel sheet surface before bonding in this embodiment, with the horizontal axis representing wavenumber and the vertical axis representing the logarithm of absorbance.

[0087] In this figure, FTIR shows that －１ OH group near 800 cm －１ and 1400 cm －１ CH group near 1000-1200 cm －１ indicates that SiO groups have been detected in the vicinity. Note that the values ​​relating to the wavenumbers measured vary slightly depending on the conditions, and are not limited to the wavenumbers shown in this figure. The values ​​are compared with a commonly used FTIR wavenumber database and include all values ​​that match with OH groups and CH groups.

[0088] The peak height for the SiO group is calculated by connecting the minimum points on both sides of the peak (maximum point) of the curve with straight lines (shown by dashed lines) and setting the zero point of the peak height with a diagonal line, thereby correcting for the background.

[0089] Here, the FTIR measurement is carried out using, for example, a Fourier transform infrared spectrometer (Micro Infrared Spectrophotometer Nicolet 6700 / Continu μm manufactured by Thermo Fisher Scientific Co., Ltd.) with a resolution of 4 cm by the ATR method. －１The detector was MCT, and the number of integrations was 64, and the peak intensity of each functional group can be handled as a corrected height from the background. The reason for using the ATR method is that, compared to ordinary reflection microscopy, it is possible to measure in a pinpoint range and calculate functional groups without including slopes near the point to be measured, so that the truly necessary high-reliability adhesive region can be clarified and the range containing sufficient functional groups can be determined.

[0090] The measurement device and method are not limited to this, and any device and conditions that allow the functional groups on the surface to be correctly detected can be used.

[0091] Due to the presence of the glass coating layer 31a having the above-mentioned highly reliable adhesive region, even if the sealing material 40 happens to absorb water, the glass coating layer 31a prevents the flange portion 31 from coming into contact with water, thereby preventing corrosion of the flange portion 31, etc.

[0092] Next, the effects of this embodiment will be described.

[0093] By clarifying the truly necessary high-reliability adhesive region, the amount of sealant required for application can be reduced, and the amount of material used in the process to form the glass coating layer can also be reduced, thereby reducing cycle time. Furthermore, by reducing the width of the sealant from 10 mm, which was previously considered necessary, to 4 mm, the amount of sealant applied can be reduced, and airtightness can be ensured without creating a labyrinth shape.

[0094] According to this embodiment, the number of OH groups that bond with the OH groups of the sealing material by hydrogen bonding increases compared to the surface state of a normal metal, and CH ３ The adhesive strength can be increased because of the intermolecular force due to the CH groups and the covalent bond between the SiO groups. This allows the adhesive strength to be increased regardless of the state of the metal surface. ３ The groups can also provide water resistance, and durability against salt water and the like can be imparted.

[0095] The inventors have found that in previous environmental resistance tests for saltwater and the like, adhesive structures such as those shown in FIG. 9 described below were able to satisfy the required adhesive strength. However, they have confirmed that the conventional adhesive structure shown in FIG. 9 cannot meet the requirements for longer life in environments where the structure comes into contact with saltwater and the like, which have become increasingly strict in recent years. They have also confirmed that the configuration of this embodiment satisfies these requirements.

[0096] Furthermore, when the housing size is large and internal pressure requirements are strict and ensuring airtightness is an issue, a typical sealing material, such as a silicone adhesive, has a tensile strength that is approximately 1.5 times stronger than the strength against shear stress at the adhesive surface. Therefore, a structure such as the electronic control device 1 of this embodiment is effective in that both the sealing material 40 and the glass coating layer 31a can withstand internal pressure with their tensile strength. In other words, the high-reliability adhesive region is positioned so that it will receive tensile stress in a direction approximately perpendicular to the adhesive surface when the pressure (internal pressure) in the internal space formed by the first housing 20 and the second housing 30 increases. This allows for high robustness, high adhesion, high reliability, and low cost.

[0097] Furthermore, by clarifying the truly necessary high-reliability adhesive area, the width of the sealant can be reduced from 10 mm, which was previously considered necessary, to 4 mm, thereby reducing the amount of sealant and glass coating applied, and cycle time. Furthermore, by reducing the width of the sealant from 10 mm, which was previously considered necessary, to 4 mm, there is no longer a need to provide a labyrinth shape in the flange, which reduces the processing costs of the housing and the amount of sealant used. Furthermore, the dimensions of the flange can be reduced, allowing for a more compact housing.

[0098] FIG. 8 is a schematic cross-sectional view showing the chemical structure of the surface of a steel sheet before bonding in a comparative example.

[0099] This figure shows a state in which OH groups exist on the surface of the housing 131. The density of the OH groups is relatively low.

[0100] FIG. 9 is a schematic cross-sectional view showing the chemical structure of the surface of the steel sheet after bonding in the comparative example.

[0101] In this figure, OH groups and CH groups present on the surface of the sealing material 140 ３ The housing 131 and the sealant 140 are bonded together by forming covalent bonds between the SiO groups and by forming hydrogen bonds between the OH groups present on the surface of the housing 131 and the OH groups of the sealant 140. ３ The group is CH ３ Since there are no groups, it is not bonded to any other functional groups.

[0102] In FIG. 4 of this embodiment, CH ３ In comparison with the intermolecular forces generated by the groups, it is believed that the adhesive strength in this comparative example is weaker by the amount of these intermolecular forces.

[0103] 10 is a graph showing an example of the analysis results of the steel sheet surface before bonding in a comparative example, with the horizontal axis representing wavenumber and the vertical axis representing the logarithm of absorbance.

[0104] In this figure, FTIR shows that －１ This indicates that OH groups have been detected in the vicinity.

[0105] Second Embodiment An electronic control device according to a second embodiment will be described with reference to Figures 11 and 12. Note that in this embodiment, descriptions of configurations that are the same as those in the first embodiment will be omitted.

[0106] FIG. 11 is an exploded perspective view showing the electronic control device according to this embodiment.

[0107] In the electronic control device 2 shown in the figure, the second housing 30 has an end portion 33. The cross section of the end portion 33 is L-shaped. The first housing 20 is provided with a peripheral groove 20a. The second housing 30 is provided with a housing end portion 30a that is a convex portion.

[0108] FIG. 12 is a cross-sectional view of a main part of the electronic control device according to this embodiment.

[0109] In this figure, a flange portion 22 (flat portion) is provided on the first housing 20, and a peripheral groove 20a is provided around the flange portion 22. A flange portion 31 is provided on the second housing 30, and an end portion 33 is provided around the flange portion 31. The end portion 33 is fitted into the peripheral groove 20a.

[0110] A glass coating layer 31a is provided on the surface of the flange portion 31 facing the flange portion 22. The glass coating layer 31a contains many OH groups and CH ３ The sealing material 40a is sandwiched between the glass coating layer 31a and the flange portion 22. The surfaces of the sealing material 40a and the glass coating layer 31a contain OH groups and CH groups. ３ The base is exposed.

[0111] A gap-filling sealant 40 is filled between the inner wall surface 22a of the peripheral groove 20a and the end 33. In other words, the gap between the inner wall surface 22a and the end 33 forms a labyrinth shape, extending the width of the adhesive surface of the sealant 40. Furthermore, if the second housing 30 including the flange portion 31 is formed from a pre-plated steel sheet, there is no plating on the cut surface during molding, and therefore, by filling the end 33 in the sealant 40 or the like, it is possible to obtain the effect of preventing corrosion of the end 33.

[0112] Third Embodiment An electronic control device according to a third embodiment will be described with reference to Fig. 13. Note that in this embodiment, the description of the same configuration as in the first embodiment will be omitted.

[0113] FIG. 13 is a cross-sectional view of a main part of an electronic control device according to the third embodiment.

[0114] In the electronic control device 1A shown in FIG. 13, in addition to the glass coating layer 31a on the flange portion 31 side of the second housing 30, a glass coating layer 22b is also formed on the flange portion 22 side of the first housing 20.

[0115] With this configuration, the sealant 40 can have a high adhesive structure similar to that of the first embodiment in the portions that contact both the first housing 20 and the second housing 30 .

[0116] Fourth Embodiment An electronic control device according to a fourth embodiment will be described with reference to Fig. 14. Note that in this embodiment, the description of the same configuration as in the second embodiment will be omitted.

[0117] FIG. 14 is a cross-sectional view of a main part of an electronic control device according to a fourth embodiment.

[0118] 14, in addition to the glass coating layer 31a on the flange portion 31 side of the second housing 30, a glass coating layer 22b is also formed on the flange portion 22 side of the first housing 20. Therefore, the sealing material 40a is sandwiched between the glass coating layer 31a and the glass coating layer 22b.

[0119] Fifth Embodiment An electronic control device according to a fifth embodiment will be described with reference to Fig. 15. Note that in this embodiment, the description of the same configuration as in the first embodiment will be omitted.

[0120] FIG. 15 is a cross-sectional view of a main part of an electronic control device according to a fifth embodiment.

[0121] 15 , in addition to the glass coating layer 31 a on the flange portion 31 side of the second housing 30, a glass coating layer 22 b is also formed on the flange portion 22 side of the first housing 20. Also, in this embodiment, unlike the first embodiment, the sealing material 40 is disposed near the peripheral edges of the flange portion 22 and the flange portion 31.

[0122] Sixth Embodiment An electronic control device according to a sixth embodiment will be described with reference to Fig. 16. Note that in this embodiment, the description of the same configuration as in the second embodiment will be omitted.

[0123] FIG. 16 is a cross-sectional view of a main part of an electronic control device according to a sixth embodiment.

[0124] In the electronic control device 1B shown in Fig. 16, the shapes of the first housing 20 and the second housing 30 are the same as those in Fig. 12. The first flat portion 23 on which the printed wiring board 10 is placed is also the same.

[0125] 16, unlike FIG. 12, a glass coating layer 31b is provided on the outer periphery of flange portion 31. In addition, a glass coating layer 22c is also provided on the surface of peripheral groove 20a of first housing 20 that faces the outer periphery of flange portion 31. A sealant 40a is sandwiched between glass coating layer 31b and glass coating layer 22c. The outer surface of sealant 40a is covered with sealant 40.

[0126] In this embodiment, both the sealing material 40a and the glass coating layers 22c, 31b, i.e., the high-reliability adhesive region, are arranged so that when the pressure (internal pressure) in the internal space formed by the first housing 20 and the second housing 30 becomes high, they are subjected to stress (shear stress) in a direction approximately parallel to the adhesive surface.

[0127] <Others> The present disclosure is not limited to the above-described embodiments and includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present disclosure, and are not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations.

[0128] The electronic control device of the present disclosure is particularly effective when the housing structure is made of hot-dip galvanized steel plate, which has excellent corrosion resistance, or lightweight aluminum die-cast.

[0129] Furthermore, electronic control devices mounted in the engine compartment are required to have a high degree of freedom in installation so that their placement in the vehicle is not restricted. The configuration of the present disclosure can also be employed in a configuration in which the electronic control device is not fixed with bolts, which simplifies the installation process and reduces costs. As an example, the configuration of the present disclosure can also be employed in a configuration in which the electronic control device is fixed by being clamped by a bracket or the like provided on the vehicle side.

[0130] Electronic control devices installed in engine compartments are subject to many requirements, including complete airtight sealing, waterproofing, heat resistance, corrosion resistance, vibration resistance, resistance to mechanical shock (shock resistance), and EMC (Electromagnetic Compatibility). Products also need to have a long life. Furthermore, they need to be able to operate under harsh operating environments.

[0131] The configuration of the present disclosure is also applicable to electronic control devices, which are becoming increasingly sophisticated and are therefore increasingly requiring larger housings and a greater number of connector poles.The configuration of the present disclosure is particularly effective in situations where it is difficult to decentralize electronic control devices or to reduce the number of connector terminal poles and make them wireless (for example, electronic control devices for engines and transmissions mounted in the engine room).

[0132] The embodiment of the present disclosure may have the following aspects.

[0133] (1) A semiconductor device comprising a first housing, a second housing fixed to face the first housing, and a sealant for sealing an internal space formed by the first housing and the second housing, wherein the sealant contains an OH group and a CH ３ At least one of the first housing and the second housing has the OH group and the CH group in at least a part of the area of ​​the surface thereof that is in contact with the sealing material. ３ An electronic control device having a glass coating film containing a group formed thereon.

[0134] (2) In the electronic control device described in (1) above, the glass coating film has a highly reliable adhesive region having a width of 4 mm or more and a film thickness of 50 nm to 300 nm.

[0135] (3) In the electronic control device described in (2) above, the highly reliable adhesive region is measured by FTIR (ATR method), and when the vertical axis is plotted as the logarithm of absorbance and the background is corrected, the peak height is 0.03 or more for SiO bonds and 0.04 or more for CH ３ The CH bond of the group is 0.003 to 0.007, and the relative ratio to the SiO bond is ３ The C-H bond (CH / SiO) of the group is 0.05 or more and 0.24 or less.

[0136] (4) In the electronic control device described in (3) above, the highly reliable adhesive region is formed directly on the surface of the first housing and the second housing with an adhesive strength of 1.0 MPa or more.

[0137] 1, 1A, 1B, 2, 2A, 2B: electronic control device, 10: printed wiring board, 11: internal space, 20: first housing, 20a: peripheral groove, 21: opening, 22: flange portion, 22a: inner wall surface, 22b, 22c, 31a, 31b, 31c: glass coating layer, 23: first flat portion, 25: heat dissipation fin, 30: second housing, 30a: housing end, 31: flange portion, 33: end, 40, 40a, 41: sealing material, 42: heat dissipation adhesive, 50, 51: screw, 60: connector, 61: housing, 63: terminal, 131: housing, 140: sealing material.

Claims

1. An electronic control device comprising: a first housing and a second housing for accommodating a circuit board; a glass coating layer formed on at least one of the first housing and the second housing; and a sealing member provided between the first housing and the second housing, wherein the glass coating layer is positioned so as to be in contact with the sealing member.

2. The electronic control device according to claim 1, wherein the sealing member is disposed so as to fill a gap between the first housing and the second housing.

3. The electronic control device according to claim 1, wherein the glass coating layer has a functional group containing carbon.

4. The electronic control device according to claim 1, wherein the glass coating layer is formed by a plasma glass coating process using a material containing an organic substance.

5. The electronic control device according to claim 1, wherein the glass coating layer has a highly reliable adhesive region having a width of 4 mm or more and a thickness of 50 nm to 300 nm.

6. The highly reliable adhesive region is determined by measuring local absorbance by FTIR (ATR method), plotting the absorbance on the vertical axis as a logarithm, and determining whether the peak height after background correction is 0.03 or more for SiO bonds and 0.03 or more for CH ３ The CH bond of the group is 0.003 to 0.007, and the relative ratio to the SiO bond is ３ The electronic control device according to claim 5 , wherein the C-H bond (CH / SiO) of the group is in the range of 0.05 to 0.

24.

7. An electronic control device as described in claim 5, wherein the high reliability adhesive region is arranged so as to receive tensile stress in a direction approximately perpendicular to the adhesive surface when the pressure in the internal space formed by the first housing and the second housing increases.