Electronic control device and method of manufacturing the same

Abstract

The constitution is to provide an electronic control device that can flexibly accommodate on-board layout and assembly of each vehicle at low cost, and that can contribute to reducing the total cost of the vehicle.　Provided is a method for manufacturing an electronic control device provided with a housing having a bracket and a connector opening for attaching to a predetermined position, wherein the housing is manufactured by a die casting method using a cavity mold that presses in a direction generally perpendicular to the connector opening, a core mold that receives the pressing of the cavity mold, and a slide mold that slides in a direction substantially orthogonal to the pressing direction. In the method for manufacturing an electronic control device, the attachment surface of the bracket has a surface horizontal to the pressing surface of the slide mold and is manufactured integrally with the housing, and furthermore, using only one slide mold, the attachment surface of the bracket that is not pressed by the slide mold has a taper surface of the cavity mold, and the taper surface is machined so that it becomes a surface that is horizontal and parallel to the pressing surface of the slide mold after demolding.

Description

Electronic control device and manufacturing method thereof

[0001] The present invention relates to an electronic control device having a circuit board on which a connector for external connection is mounted and a housing that houses the circuit board and the connector, and more particularly to an electronic control device that is mounted on a vehicle for use, and a method for manufacturing the same.

[0002] Modern vehicles are controlled by numerous electronic devices, such as engine control units (ECUs) and advanced driver assistance systems (ADAS). The printed circuit boards (PCBs) of these electrical devices are generally housed in waterproof cases to prevent moisture from entering. It is also common to install heat sinks (heat dissipation fins) on the cases to dissipate heat generated by the electronic devices mounted on the PCBs.

[0003] Furthermore, a connector for extracting signals to the outside is provided on the circuit board (PCB), and therefore an opening for the connector is provided in the case. The housing is generally composed of a pair of cases that can be separated into upper and lower halves for ease of manufacturing. The heat dissipation fins described above are integrally formed on one of the pair of cases. The heat dissipation effect can be enhanced by using a die-cast case made of aluminum or other material with good thermal conductivity for the case with the heat dissipation fins. Such an electronic control device is disclosed, for example, in Patent Document 1.

[0004] The housing of the electronic control device disclosed in Patent Document 1 has a connector opening formed when the upper first case and the lower second case are assembled, exposing a portion of the connector to the outside, while accommodating the remainder of the connector and the circuit board within an internal space. The first case and the second case are die-cast aluminum products. A plurality of heat dissipation fins are integrally formed on the top surface of the first case.

[0005] JP 2016-143852 A

[0006] The on-board layout and assembly method of such electronic control units differs from vehicle to vehicle, and even when installing electronic control units with the same housing, it is necessary to design and manufacture individual mounting brackets for each vehicle model, which leads to increased costs.

[0007] An object of the present invention is to provide an electronic control device that can flexibly accommodate the on-board layout and assembly of each vehicle at low cost and contribute to reducing the total cost of the vehicle.

[0008] The present invention has the following configuration to achieve the above object.

[0009] A method for manufacturing an electronic control device that has a housing having at least a bracket for mounting at a predetermined position and a connector opening, wherein the housing is manufactured by a die-casting method using a cavity mold that presses in a direction generally perpendicular to the connector opening, a core mold that receives the pressure of the cavity mold, and a slide mold that slides in a direction generally perpendicular to the pressing direction, and the mounting surface of the bracket has a surface that is horizontal to the pressing surface of the slide mold and is manufactured integrally with the housing; and an electronic control device manufactured by this manufacturing method.

[0010] To provide an electronic control device that can flexibly accommodate the on-board layout and assembly of each vehicle at low cost and contribute to reducing the total cost of the vehicle.

[0011] FIG. 1 is a cross-sectional view of an electronic control device according to the present invention. FIG. 2 is a perspective view of a first case shown in FIG. 1. FIG. 3 is a perspective view of an electronic control device according to the present invention. FIG. 4 is a perspective view of an upper case of the electronic control device shown in FIG. 3. FIG. 5 is a schematic view of a mold used when casting the upper case of the present invention. FIG. 6 is another example of a schematic view of a mold used when casting the upper case of the present invention. FIG. 7 is a view showing the structure of a bracket of the upper case of the present invention. FIG. 8 is a view showing a bolt fastening surface of a bracket of the upper case of the present invention. FIG. 9 is a view showing an example in which the bracket of the upper case of the present invention is L-shaped. FIG. 10 is a view showing a manufacturing flow for the upper case of the present invention. FIG. 11 is a view showing a conventional electronic control device.

[0012] An embodiment of the present invention will be described below with reference to the accompanying drawings. Note that the embodiment shown in the accompanying drawings is an example of the present invention, and the present invention is not limited to this embodiment. In the drawings, "Up" indicates the top, and "Dn" indicates the bottom.

[0013] An electronic control device 10 according to a first embodiment will be described with reference to FIGS.

[0014] As shown in FIG. 1, the electronic control device 10 includes a circuit board 12 on which electronic components 11 are mounted, a connector 13 for external connection mounted on the circuit board 12, and a housing 15 having an internal space 14 for accommodating the circuit board 12.

[0015] The housing 15 is composed of a first case 20 that is open on the bottom side and a second case 30 that is open on the top side. The upper first case 20 and the lower second case 30 are stacked on top of each other and assembled with screws 31, thereby forming an internal space 14 in the housing 15.

[0016] The first case 20 is a die-cast product made of a light metal with excellent thermal conductivity, such as aluminum (including aluminum alloys), while the second case 30 is a press-molded product made of a metal plate.

[0017] Furthermore, the housing 15 has a connector opening 21 that is formed when the first case 20 and the second case 30 are assembled. This connector opening 21 is formed, for example, only in the first case 20. The housing 15 exposes a portion of the connector 13 to the outside through the connector opening 21, while accommodating the remaining portion of the connector 13 and the circuit board 12 in the internal space 14. Note that the housing 15 may also be configured with the first case 20 and the second case 30 upside down.

[0018] 1 and 2, when viewed from the connector opening 21 side (viewed from the direction of arrow Ar), the first case 20 has a surface 22 (top surface 22) opposite the second case 30, a back surface 23 opposite the connector opening 21, and left and right side surfaces 24 (only one side is shown). The top surface 22 is a flat plane.

[0019] FIG. 3 is a perspective view of the electronic control device 100 according to the present invention.

[0020] The electronic control unit 100 is used by screwing a body bracket 101 for mounting to a bracket 102 on the vehicle side. The body-side bracket 101 is fixed to the vehicle side by screws. The body-side bracket 101 can take various shapes depending on the mounting structure on the vehicle side. Reference numeral 102 denotes an upper case, 104 denotes heat dissipation fins provided on the upper case 103, 105 denotes a connector, and 108 denotes a lower case to which a circuit board is fixed.

[0021] FIG. 4 is a perspective view of the upper case 103 of the electronic control device of FIG.

[0022] You can see the screw mounting holes 105 of the bracket 102. Screws are inserted into the screw mounting holes to fasten the body-side bracket 101. The connector opening 107 is an opening into which a connector is inserted when the upper case 103 and the lower case 108 are combined.

[0023] That is, the upper case 103 is a die-cast housing having a connector opening 107, and the bracket (mounting portion) 102 is integrally formed with the housing.

[0024] The mounting surface of the bracket (mounting portion) 102 is configured to be parallel to the opening direction of the connector opening 107. This configuration has the effect of facilitating the installation work when installing the electronic control unit on the vehicle side, because the connector installation and the screw installation direction to the bracket 102 can be the same. Furthermore, because the installation direction can be limited to one surface, the installation space can be reduced, and the effect of improving the degree of freedom in installation, such as in retrofitting, can be expected.

[0025] Next, the manufacturing process of the upper case 103 will be described.

[0026] The upper case 103 is manufactured by die-casting. The manufacturing method will be explained using Figure 5. The upper case is pressed from above and below by a fixed mold (core) 201 and a movable mold (cavity) 202, and at the same time, a pair of slide molds (core molds) 203 and 204 are pressed in a direction perpendicular to the connector opening, and the mold is split to perform casting.

[0027] At this time, the mounting surface of the bracket 102 can be changed in any direction of 360 degrees relative to the connector opening surface by changing the angle of the pressing surface of the slide mold.

[0028] Furthermore, using a pair of slide molds makes it possible to achieve parallelism and flatness of the screw fastening surface of the bracket 102, but die casting using a total of four molds can sometimes result in problems such as increased manufacturing costs and complicated mold maintenance.

[0029] As a method for solving such problems, as shown in Figure 6, a mold can be configured so that precision is achieved by using a slide mold 301 only on the side where the body-side bracket 101 is fastened, and the side where the body-side bracket 101 is not fastened has a taper (draft taper) 302 that allows the cavity mold to be removed. In this case, it is effective to perform surface finishing so that the tapered surface is parallel to the opposing surface in order to eliminate the effect of the draft taper of the mounting portion.

[0030] This will be explained using Figure 7. Figure 7(a) is a front view of the bracket 102, and Figure 7(b) shows a cross section taken along the line AA in Figure 7(a). As shown in Figure 7(b), it is effective to perform cutting so that the surface (abutment surface) with which the body bracket 101 comes into contact is parallel to the opposing bolt (screw) fastening surface.

[0031] In this case, it is effective for reducing costs to post-process only the bolt fastening area to form a fastening surface parallel to the back surface in order to shorten the cutting time, as shown in Figure 8. This ensures the appropriate axial force of the screw.

[0032] The bracket may also be L-shaped as shown in Figures 9(a) to 9(d). This structure may improve the ease of assembly with the vehicle-side bracket.

[0033] Figure 10 shows the manufacturing flow for the upper case 103 of the present invention. First, a mold release agent and lubricant are applied to the die-casting mold (step s100). Next, the fixed core mold, the movable cavity mold, and the slide mold for creating the bracket (in this figure, only one slide mold) are aligned to the pouring position (mold clamping: step s101). Molten aluminum is poured into the aligned molds (pouring: step s102). The movable cavity and slide molds are moved and injected to fill the molten metal (step s103). The mold is cooled while maintaining pressure until the molten metal solidifies (step s105). After cooling is complete, the mold is opened (step s105). The die-cast casting is removed from the mold (mold release / removal step s106). Any burrs on the removed casting are removed using a grinder or similar tool (deburring step s107). Post-processing steps, such as cutting, tapping, and surface finishing, are performed (s108). This process completes the manufacturing of the upper case of the present invention. <Comparative Example> Figure 11 shows a conventional electronic control device. The connector openings are 2100, 3100, and 3200. The bracket is 600. The upper cases of conventional electronic control devices have generally been manufactured using only two molds: a cavity mold and a core mold, with an emphasis on ease of manufacture. Therefore, the bracket 600 has a fastening surface parallel to the circuit board (i.e., perpendicular to the connector opening surface).

[0034] If the bolt (screw) fastening surface of the bracket 600 is perpendicular to the connector opening surface, it is necessary to use a large number of screws when attaching the body bracket to the upper case.

[0035] Furthermore, when tightening a screw, the screwdriver must be held perpendicular to the longitudinal direction of the screw, so the screw must be tightened while pointing the screwdriver in a different direction. If the connector insertion direction and the screw tightening direction are different, the assembly work of the electronic control unit into the vehicle becomes complicated and requires a considerable amount of work space.

[0036] 10, 100...Electronic control device, 12...Circuit board, 13...Connector, 14...Internal space, 15...Housing, 20, 120...First case, 21...Connector opening, 22...Surface opposite to second case (top surface), 23...Rear surface opposite to connector opening, 25...Boundary between top surface and rear surface, 27...Traces, 30...Second case, 40...Heat dissipation fin

Claims

1. A manufacturing method for an electronic control device comprising a housing having at least a bracket for mounting at a predetermined position and a connector opening, wherein the housing is manufactured by a die casting method using a cavity mold that presses in a direction generally perpendicular to the connector opening, a core mold that receives the pressure of the cavity mold, and a slide mold that slides in a direction generally perpendicular to the pressing direction, the mounting surface of the bracket has a surface that is horizontal to the pressing surface of the slide mold and is manufactured integrally with the housing, and further, only one slide mold is used, the mounting surface of the bracket that is not pressed by the slide mold has a draft taper surface of the cavity mold, and the draft taper surface is machined so that it becomes a surface parallel to the surface horizontal to the pressing surface of the slide mold after demolding.

2. A method for manufacturing an electronic control unit as claimed in claim 1, characterized in that the cutting process cuts only the vicinity of the fastening surface of the screw for fixing the bracket.

3. A method for manufacturing an electronic control device as described in claim 1, wherein the bracket has a second mounting surface that is generally perpendicular to the mounting surface that is horizontal to the pressing surface of the slide mold.

4. An electronic control device comprising a housing having at least a bracket for mounting at a predetermined position and a connector opening, wherein the housing has a mounting surface for the bracket that is generally parallel to the connector opening and is integral with the housing, and further wherein one of the mounting surfaces of the bracket has a tapered surface of a die-casting mold, and at least a portion of the tapered surface of the die-casting mold is machined to be parallel to the other mounting surface of the bracket.

5. An electronic control device according to claim 4, wherein the surface machined to be parallel to the other mounting surface of the bracket is only the vicinity of the fastening surface of the screw for fixing the bracket.

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