WO2018235960A1 - Electronic control unit - Google Patents

Abstract

The present invention comprises: a substrate on which an electronic part is loaded; a resin body, which is a container for storing the substrate and a portion of which has a storing section that is open as a recess for storing the substrate; and a metal body that covers the storing section of the resin body and is supported at a rim surrounding the storing section. A ring-shaped welding section, which contacts the storing section, is formed on the periphery of the surface of the metal body that faces the storing section as a protruding section surrounding the perimeter of the substrate stored in the storing section. Multiple ring-shaped recesses and protrusions are formed at least at the periphery of the ring-shaped welding section, and the ring-shaped welding section is welded to the storing section by laser light irradiated from the outside of the metal body.

Description

Electronic control unit

The present invention relates to an electronic control device including a substrate on which various electronic components are mounted.

As background art of this technical field, there is JP-A-2016-132131 (patent document 1). In this publication, “a different kind of airtightness is formed by forming a joint having a plurality of groove portions substantially parallel to each other at the time of laser scanning processing at the interface between the dissimilar material and the metal material when joined to a dissimilar material. A material bonding metal material, wherein the bonding portion has a groove width W and a groove depth H in the groove in a cross-sectional view cut in a direction perpendicular to the groove formed on the surface of the metal material. Assuming that the groove area formed at the time of laser scanning processing is A, and the area of protrusions formed of burrs formed on the surfaces of both sides of the groove at the laser scanning processing is B and C, the area ratio is A dissimilar metal-bonded metal material having a relationship of A + B + C) / (W × H) ≧ 1.00.

JP, 2016-132131, A

According to Patent Document 1, there is a case where a joint having a plurality of grooves which are substantially parallel to each other is formed at the time of laser scanning processing at the interface between the dissimilar material and the metal material when joining dissimilar materials. In an electronic device that is supposed to be used, if reliability can not be ensured even for salt damage, corrosion progresses to the inside in a salt water resistance test such as a salt spray test.

Therefore, the present invention provides an electronic control device capable of preventing peeling of the bonding interface between the metal and the resin even in the salt water resistance test.

In order to solve the above problems, the present invention is a substrate on which an electronic component is mounted, and a container for storing the substrate, and a storage portion opened as a recess for storing the substrate in a part thereof. An outer peripheral surface of an opposing surface of the metal body facing the storage portion, the resin body having a resin body, and a metal body covering the storage portion of the resin body and supported at an edge around the storage portion An annular welding portion is formed on the side as a convex portion surrounding the periphery of the substrate accommodated in the accommodation portion and in contact with the accommodation portion, and at least the outer circumferential side of the annular welding portions is provided with a plurality of annular The annular welding portion is welded to the housing portion by laser light emitted from the outside of the metal body.

According to the present invention, peeling of the bonding interface between the metal and the resin can be prevented even in the salt water resistance test.

Problems, configurations, and effects other than those described above will be apparent from the description of the embodiments below.

FIG. 1 is a perspective view showing an entire configuration of an electronic control unit according to a first embodiment of the present invention. It is an exploded perspective view of an electronic control unit concerning Example 1 of the present invention. It is a figure of an electronic control unit concerning Example 1 of the present invention, and (A) is a bottom view of an electronic control unit, (B) is an important section expanded cross section in the XX line direction of (A). FIG. It is a figure for demonstrating the structure of a comparative example, Comprising: (A), (B) is a principal part expanded sectional view of a comparative example. It is a principal part expanded sectional view of the electronic control unit concerning Example 2 of the present invention. It is a principal part expanded sectional view of the electronic control unit concerning Example 3 of the present invention. It is a principal part expanded sectional view of the electronic control unit concerning Example 4 of this invention. It is a principal part expanded sectional view of the electronic control unit concerning Example 5 of the present invention. It is a principal part expanded sectional view of the electronic control unit concerning Example 6 of the present invention. It is a principal part expanded sectional view of the electronic control unit concerning Example 7 of the present invention.

Hereinafter, Example 1 will be described using the drawings.
FIG. 1 is a perspective view showing an entire configuration of an electronic control unit according to a first embodiment of the present invention. In FIG. 1, the electronic control unit is used, for example, as an automobile engine control unit (ECU), and a substantially flat metal base 1 and a substantially cubic resin cover 2 are joined by an adhesive, welding or welding. It is shaped like a box. The metal base 1 is made of, for example, aluminum, and a plurality of radiation fins 1 a are formed on the surface of the metal base 1.

FIG. 2 is an exploded perspective view of the electronic control unit according to the first embodiment of the present invention. In FIG. 2, a flat substrate 3 is disposed between the metal base 1 and the resin cover 2. The substrate 3 is fixed to the bottom side of the metal base 1 by a bolt or the like. The resin cover 2 is a container for storing the substrate 3 and is configured as a resin body having a storage portion 2a opened as a recess (space portion) for storing the substrate 3 in a part (central portion) thereof. . An annular support portion 2 b for supporting the metal base 1 is formed on the peripheral edge of the housing portion 2 a of the resin cover 2. The metal base 1 covers the housing portion 2a of the resin cover 2 and is configured as a metal body supported by the support portion 2b around the housing portion 2a. A circuit pattern (not shown) is formed on the substrate 3 housed in the housing portion 2a, and electronic components 3a such as a CPU (Central Processing Unit), a resistor, and a capacitor are mounted. That is, an engine control unit (ECU) is configured by the various electronic components 3 a mounted on the substrate 3. At this time, the metal base 1 and the resin cover 2 are used to protect the substrate 3. The substrate 3 and the electronic component 3a may suffer from a load due to heat. In particular, when moisture intrudes into the inside of the resin cover 2, the substrate 3 gets wet and the electronic component 3a does not operate normally. Therefore, the reliability of bonding of the metal base 1 and the resin cover 2 becomes important.

FIG. 3 is a diagram of the electronic control unit according to the first embodiment of the present invention, wherein (A) is a bottom view of the electronic control device, and (B) is in the XX direction of (A). It is a principal part expanded sectional view. In (A) and (B) of FIG. 3, an annular step portion 1 b is formed on the outer peripheral side of the upper portion of the metal base 1. The resin cover 2 side of the central portion of the metal base 1 on the outer peripheral side of the bottom surface of the metal base 1 (the surface opposite to the substrate 3 or the resin cover 2) An annular welding portion 1c is formed in contact with the storage portion 2a as a convex portion protruding to surround the periphery of the substrate 3 stored in the storage portion. A plurality of annular concavo-convex portions 1 d are formed on the outer peripheral side of the bottom surface of the welded portion 1 c (the surface facing the housing portion 2 a of the resin cover 2). Each concave portion of the uneven portions 1d is formed as a groove 1e, and the depth of each groove 1e is about 0.1 mm, and the width (pitch) between each groove (each concave portion) is 0.1 mm. . At this time, the grooves 1e on the outermost side among the grooves 1e are formed on the end face on the bottom side of the metal base 1 so as to be exposed as notches. That is, on the outer peripheral side of the bottom surface of the welded portion 1c, a groove 1e serving as a notch is formed in a region facing the peripheral edge (support portion 2b) of the storage portion 2a. Each groove 1 e can be formed, for example, by laser processing that emits a laser beam 4. At this time, each uneven portion 1 d is formed as a roughened portion roughened by the laser light 4. In addition, the width | variety (pitch) between each convex part pinched by each groove | channel 1e among several cyclic | annular uneven parts 1d is also formed by 0.1 mm.

When the metal base 1 to which the substrate 3 is fixed is stored in the storage portion 2a of the resin cover 2, the metal base 1 is supported by the support portion 2b of the resin cover 2 in the step portion 1b. The bottom surface is in contact with the surface of the storage portion 2 a of the resin cover 2.

Here, when the laser beam 4 is sequentially irradiated toward the entire area of the welded portion 1c of the metal base 1 from above the metal base 1, the portion irradiated with the laser beam 4 is heated and a part of the resin cover 2 is melted. Thus, the surfaces of the welded portion 1c and the storage portion 2a are joined (welded) to each other. At that time, pressure is applied to the metal base 1 and the resin cover 2, and a part of the melted resin in the resin cover 2 becomes the protruding portion (burr) 5, and the supporting portion 2 b and the welded portion 1 c It is pushed out to the gap 6 between.

Under these conditions, a salt spray test (a test in which salt water is sprayed from the outside of the electronic control unit and salt water is attached to the side of the metal base 1) was tested. There were no cracks in the bonding interface with the resin cover 2. Specifically, for the salt spray test, no leak occurred even at 40 cycles, or a crack did not occur at the bonding interface between the metal base 1 and the resin cover 2 or inside the resin cover 2. Further, even if salt water infiltrates from the gap 6, the metal base 1 makes the portion corroded by salt water as slow as possible, or the strength higher than the stress generation due to the corrosion of the metal base 1 makes the metal base 1 and the resin cover 2 Can be extended the life for salt spray. That is, by providing the concavo-convex portion 1d including the plurality of grooves 1e in the region facing the gap 6 into which the salt water infiltrates in the metal base 1, the bonding strength of the outer peripheral side surface portion of the metal base 1 is strengthened. It becomes possible to prevent exfoliation due to corrosion of the base 1. In addition, by forming the outer peripheral side of the bottom surface of the welded portion 1c of the metal base 1 into a groove structure including a plurality of grooves 1e, it is possible to suppress such a stress that peels the resin from the resin cover 2; It is considered that the life for the spray test is extended.

Comparative example

FIG. 4 is a figure for demonstrating the structure of a comparative example, Comprising: (A), (B) is a principal part expanded sectional view of a comparative example. In (A) and (B) of FIG. 4, the comparative example is a region facing the gap 6 at the bottom surface of the welded portion 1 c, and a constant distance from the outer peripheral end surface (side surface) of the welded portion 1 c of the metal base 1. , And a flat portion 1g is formed between the outermost groove 1f and the side surface of the metal base 1. As shown in FIG.

When a salt spray test was performed in such a state, it was confirmed that a crack was generated in the bonding interface between the metal base 1 and the resin cover 2 due to the progress of the corrosion of the metal base 1. Specifically, leaks did not occur up to 30 cycles in the salt spray test, but leaks occurred at 40 cycles, and cracks occurred at the bonding interface between the metal base 1 and the resin cover 2 or inside the resin cover 2 Entered.

The cause is that the peeling force is exerted on the bonding interface between the metal base 1 and the resin cover 2 due to the corrosion of the metal base 1, so that the stresses F1 and F2 due to the corrosion occur as shown in FIG. 4 (A). That is, when the flat portion 1g exists between the groove 1f and the side surface of the metal base 1, the corrosion portion spreads on the metal base 1, and the stress F1 in the horizontal direction and the stress F2 in the vertical direction are generated as the stress in two directions. Do. When the corrosion further progresses, the volume expansion due to the progress of the corrosion of the metal base 1 also progresses, and as shown in FIG. 4B, a part of the resin cover 2 is further extruded in the peeling direction, and finally the metal base It is considered that the bonding interface between 1 and the resin cover 2 peels off.

According to Example 1, peeling of the bonding interface between the metal base 1 and the resin cover 2 can be prevented also in the salt spray test. Specifically, the bonding strength of the outer peripheral side surface of the metal base 1 is strengthened by providing the plurality of concavo-convex portions 1 d including the plurality of grooves 1 e in a region facing the gap 6 into which salt water infiltrates in the metal base 1. Thus, it is possible to prevent peeling of the metal base 1 due to corrosion. In addition, by making the outer peripheral side of the bottom surface of the welded portion 1c of the metal base 1 into a groove structure including a plurality of grooves 1e, it is possible to suppress such a stress that peels the resin from the resin cover 2; Life can be extended. Therefore, it is resistant to general reliability tests (high temperature tests, thermal shock tests, etc.), and good reliability can be ensured even in salt spray tests.

Although a groove having a depth of 0.1 mm is provided as the groove 1e, the same effect can be obtained also by providing a surface with unevenness on the surface of the metal base 1 by sand blasting or shot blasting.

FIG. 5 is an enlarged sectional view of an essential part of an electronic control unit according to a second embodiment of the present invention. In the second embodiment, a plurality of grooves 1e are formed on the entire bottom surface of the welded portion 1c from the outer peripheral side to the inner peripheral side, and the other configuration is the same as that of the first embodiment. Each groove 1e is formed to have a groove depth of about 0.1 mm and a width (pitch) between the grooves of 0.1 mm. At this time, the grooves 1e on the outermost side among the grooves 1e are formed on the end face on the bottom side of the metal base 1 so as to be exposed as notches.

According to the second embodiment, the same effect as that of the first embodiment can be obtained, and since the concavo-convex structure is adopted for the entire welded portion, the joint strength of the entire welded portion is larger than that of the first embodiment. Life improves for salt spray tests.

FIG. 6 is an enlarged sectional view of an essential part of an electronic control unit according to a third embodiment of the present invention. In the third embodiment, a plurality of grooves 1e and 1h having different pitches are formed in a plurality of groups all over the bottom surface of the welded portion 1c from the outer peripheral side to the inner peripheral side. Is the same as in the first embodiment. Each groove 1e belonging to the first group is formed with a groove depth of about 0.1 mm and a width (pitch) between grooves of 0.1 mm, and each groove 1h belonging to the second group has a groove depth The width (pitch) between the grooves is about 0.3 mm at about 0.1 mm.

According to the third embodiment, the same effect as that of the first embodiment can be obtained, and the number of grooves can be reduced more than the second embodiment. Therefore, the reliability for the salt spray test is improved, and the grooves are formed. It becomes possible to shorten time. Further, by making the pitch of the outer grooves 1e denser (shorter) than the pitch of the grooves 1h, there is an effect of suppressing corrosion by salt water from the outside. Further, by making the pitch of the groove 1h closer to the inner side wider than the pitch of the groove 1e, the bonding strength of the metal-resin interface between the metal base 1 and the resin cover 2 becomes strong, and peeling at the metal-resin interface The crack inside the resin is eliminated and the life is further improved.

FIG. 7 is an enlarged sectional view of an essential part of an electronic control unit according to a fourth embodiment of the present invention. In the fourth embodiment, an annular protrusion 1i is formed on the inner peripheral side of the groove 1e in the bottom surface of the welded portion 1c, and the protrusion 1i is coupled to the storage portion 2a of the resin cover 2 corresponding to the protrusion 1i. The recess 2 c is formed, and the protrusion 1 i and the recess 2 c are coupled to each other. The other configuration is the same as that of the first embodiment.

According to the fourth embodiment, the same effect as that of the first embodiment can be obtained, and the bonding strength between the metal base 1 and the resin cover 2 is increased. Therefore, even when corrosion occurs, the bonding strength is higher than stress due to corrosion. Becomes hard to peel off. Further, by providing the projections 1i, the stress applied to the bonding portion (bonding interface) between the metal base 1 and the resin cover 2 can be further alleviated, so that the generation of the stress due to the corrosion becomes strong.

FIG. 8 is an enlarged sectional view of an essential part of an electronic control unit according to a fifth embodiment of the present invention. In the fifth embodiment, a plurality of grooves 1j are formed substantially horizontally (in a direction perpendicular to the wall surface of the support 2b) on the outer peripheral side (the side facing the gap 6) of the weld 1c. The configuration is the same as that of the first embodiment.

At the time of laser welding, when the metal base 1 and the resin cover 2 are joined, a part of the resin cover 2 is melted, excess resin is generated as burrs 5, and the burrs 5 overflow into the gaps 6. At this time, a part of the burr 5 is introduced into each groove 1j. For this reason, a strong metal-resin joint is formed on the outer peripheral side of the weld 1c.

According to the fifth embodiment, the same effect as that of the first embodiment can be obtained, and the bonding strength of metal and resin on the outer peripheral side surface of the welded portion 1c can be enhanced. In contrast, the life is improved.

FIG. 9 is an enlarged sectional view of an essential part of an electronic control unit according to a sixth embodiment of the present invention. In the sixth embodiment, a plurality of grooves 1k are inclined in the direction (approximately 45 degrees with respect to the wall surface of the support portion 2b) instead of the plurality of grooves 1j on the outer peripheral side (the side facing the gap 6) of the welded portion 1c. The other configuration is the same as that of the fifth embodiment.

Even when burrs 5 are generated during laser welding, since the grooves 1k are formed in the inclined direction, the burrs 5 are more easily introduced into the grooves 1k than in the fifth embodiment.

According to the sixth embodiment, the same effect as that of the first embodiment can be obtained, and the bonding strength of metal and resin on the outer peripheral side surface of the welded portion 1c can be enhanced. In contrast, the life is improved.

FIG. 10 is an enlarged sectional view of an essential part of an electronic control unit according to a seventh embodiment of the present invention. In the seventh embodiment, the ratio of the height 13 from the welding surface (bottom surface) of the metal base 1 to the laser irradiation surface (upper surface of the metal base 1) and the depth 14 of the groove 1e is optimized. The configuration is the same as that of the first embodiment.

In FIG. 10, the height 13 from the welding surface (bottom surface) of the metal base 1 to the laser irradiation surface (upper surface of the metal base 1) is 2.5 mm, and the depth 14 of the groove 1 e is 0.1 mm. The ratio is 1:25.

In order for the heat generated by the laser beam 4 to transfer the heat necessary to melt the resin cover 2, the thinner the height 13 from the welding surface to the laser irradiation surface, the easier the heat can be transmitted and the easier it is to conduct heat. By using the metal base 1, it is possible to change the height 13 from the welding surface to the laser irradiation surface. Also, with regard to the depth 14 of the groove 1e, the resin flows and the resin penetrates into each groove 1e to increase the bonding strength, but if the depth 14 of the groove 1e is made too deep, processing becomes difficult , Also expensive. In addition, the possibility of the resin entering into the groove 1e becoming insufficient becomes high, and thus it is expected that problems such as failure to join can occur.

Therefore, in the seventh embodiment, the welding surface of the metal base 1 is used in order for the heat generated by the laser beam 4 to transmit the heat necessary to melt the resin cover 2 and to facilitate the processing of each groove 1e. The ratio of the height 13 from (bottom surface) to the laser irradiation surface (upper surface of the metal base 1) and the depth 14 of each groove 1e is set to 1:25.

The height (the depth of the groove) when the surface shape is roughened by general sand blasting or shot blasting is about 0.002 mm to 0.02 mm. In this case, the ratio of the groove depth to the height 13 from the welding surface (bottom surface) of the metal base 1 to the laser irradiation surface (upper surface of the metal base 1) is 1: 1250 to 1: 125. Since the salt spray resistance is improved by providing fine irregularities by blasting or the like on the surface of the metal base 1, the groove depth and welding of the metal base 1 are made to have a ratio of at least 1:25 or more. It is desirable to form a height 13 from the surface (bottom surface) to the laser irradiation surface (upper surface of the metal base 1).

The present invention is not limited to the embodiments described above, but includes various modifications. For example, the embodiments described above are described in detail in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the configurations described. Also, part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. In addition, with respect to a part of the configuration of each embodiment, it is possible to add, delete, and replace other configurations.

Reference Signs List 1 metal base, 1a heat radiation fin, 1b step portion, 1c welded portion, 1d uneven portion, 1e, 1f, 1h, groove, 1i protrusion, 1j, 1k groove, 2 resin cover, 2a storage portion, 2b support portion, 3 substrate , 3a electronic parts, 4 laser light, 5 protrusion (burr), 6 gaps, 13 laser irradiated surface height, 14 groove depth

Claims (11)

A substrate on which electronic components are mounted,
A container for storing the substrate, the resin body having a storage portion opened as a recess for storing the substrate in a part of the container;
And a metal body which covers the storage portion of the resin body and is supported on an edge around the storage portion,
An annular welded portion is formed on the outer peripheral side of the opposing surface of the metal body facing the storage portion, the annular weld portion being a convex portion surrounding the periphery of the substrate stored in the storage portion, and being in contact with the storage portion.
A plurality of annular uneven portions are formed on at least the outer peripheral side of the annular welded portion,
The electronic control unit according to claim 1, wherein the annular welding portion is welded to the housing portion by a laser beam emitted from the outside of the metal body. The electronic control device according to claim 1, wherein
The plurality of annular uneven portions are
An electronic control unit characterized in that it is formed as a roughened portion roughened by the laser light. The electronic control device according to claim 1 or 2, wherein
One of the plurality of annular concavo-convex parts is formed as a notch in a region facing the peripheral edge of the storage part on the outer peripheral side of the annular welded part. Electronic control unit. The electronic control device according to claim 3, wherein
An electronic control unit characterized in that among the plurality of annular concavo-convex portions, pitches between the respective concave portions are set to the same length. The electronic control device according to claim 3, wherein
The plurality of annular uneven portions are
Among the plurality of annular concavo-convex portions, the pitch between the respective concave portions is set to the same length, and is formed from the outer peripheral side to the inner peripheral side of the annular welded portion. Electronic control unit. The electronic control device according to claim 3, wherein
The plurality of annular uneven portions are
Among the plurality of annular concavo-convex portions, the pitch between the concave portions is divided into a plurality of groups, and the pitch of each group is set. An electronic control unit characterized by being set to different lengths. The electronic control device according to claim 3, wherein
The plurality of annular uneven portions are
Of the plurality of annular concavo-convex portions, the pitch between the respective concave portions is formed from the outer circumferential side to the inner circumferential side of the annular welded portion, and the first group existing on the outer circumferential side and the inner circumferential side In the second group, the pitch of each group is set to a different length, and the pitch of the first group is set shorter than the pitch of the second group An electronic control unit characterized by The electronic control device according to claim 3, wherein
An annular protrusion is formed on the inner peripheral side of the plurality of annular uneven portions in the annular welded portion, and an annular surface coupled to the protrusion on the surface facing the annular protrusion in the storage portion. An electronic control unit characterized in that a concave portion is formed. The electronic control device according to any one of claims 1 to 8, wherein
An electronic control unit characterized in that a plurality of annular grooves are formed in a region of the annular welding portion facing the peripheral edge of the storage portion. The electronic control device according to claim 9, wherein
The electronic control device according to claim 1, wherein the plurality of annular grooves are formed in a perpendicular direction or an inclined direction with respect to the peripheral edge of the storage portion. The electronic control device according to any one of claims 1 to 10, wherein
The depth of each recess among the plurality of annular concavo-convex parts, and the height from the irradiation surface of the metal body to which the laser beam is irradiated to the welding surface where the annular welding part is welded to the housing part An electronic control unit characterized in that the ratio of is set to 1:25 or more.

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