Electronic control device and method for 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

Technical Field

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

Background Art

[0002] In recent years, vehicles are controlled by a number of electronic devices such as an engine control unit (ECU) and an advanced driver assistance system (ADAS). Printed circuit boards (PCBs) of these electric devices are generally housed in a waterproof case (housing) to prevent moisture intrusion. Further, a heat sink (radiating fins) is generally provided in the case to dissipate heat generated from electronic devices mounted on the PCB.

[0003] In addition, since a connector for extracting a signal to the outside is provided on the circuit board (PCB), an opening for the connector is provided in the case. The housing is generally composed of a pair of cases that can be divided vertically from the viewpoint of ease of manufacturing. One of the pair of cases integrally forms the above-described radiating fins. By making the case provided with the radiating fins a die-cast product using a material with good thermal conductivity such as an aluminum material, the heat dissipation effect is enhanced. Such an electronic control device is disclosed in, for example, Patent Document 1.

[0004] The housing of the electronic control device disclosed in Patent Document 1 exposes a part of the connector to the outside through an opening for the connector formed in a state where the upper first case and the lower second case are assembled, and the remaining part of the connector and the circuit board are housed in the internal space. The first case and the second case are die-cast products of aluminum. A plurality of radiating fins are integrally formed on the upper surface of the first case.

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] Japanese Patent Publication No. 2016-143852 [Overview of the Initiative] [Problems that the invention aims to solve]

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

[0007] The objective of the present invention is to provide an electronic control device that can be flexibly adapted to the on-board layout and assembly of each vehicle at a low cost, and that can contribute to reducing the overall cost of the vehicle. [Means for solving the problem]

[0008] The configuration of the present invention for achieving the above objective is as follows.

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

[0010] To provide an electronic control unit that is low-cost, can flexibly adapt to the on-board layout and assembly of each vehicle, and contributes to reducing the overall cost of the vehicle. [Brief explanation of the drawing]

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

Embodiments for Carrying Out the Invention

[0012] Embodiments of the present invention will be described below based on the attached drawings. The forms shown in the attached drawings are examples of the present invention, and the present invention is not limited to such forms. In the drawings, Up indicates up and Dn indicates down.

Examples

[0013] The electronic control device 10 of Example 1 will be described while referring to FIGS. 1 to 2.

[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 housing the circuit board 12.

[0015] The housing 15 is composed of a first case 20 with an open bottom and a second case 30 with an open top. By overlapping the upper first case 20 and the lower second case 30 and assembling them with screws 31, an internal space 14 is formed in the housing 15.

[0016] The first case 20 is a die-cast product of a light metal with excellent thermal conductivity such as aluminum (including aluminum alloy). The second case 30 is a press-formed product of a metal plate.

[0017] Furthermore, the housing 15 has a connector opening 21 formed in a state where 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 houses a part of the connector 13 outside through the connector opening 21 while housing the remaining part of the connector 13 and the circuit board 12 in the internal space 14. Note that the housing 15 may have a configuration in which the first case 20 and the second case 30 are reversed up and down.

[0018] As shown in FIGS. 1 and 2, the first case 20 has a surface 22 (upper surface 22) on the side opposite to the second case 30, a back surface 23 opposite to the connector opening 21, and left and right side surfaces 24 (only one side is shown) when viewed from the side of the connector opening 21 (viewed from the direction of the Ar arrow). The upper 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 device 100 is used with a body bracket 101 for attaching to the vehicle side screwed to a bracket 102. The body side bracket 101 is screwed and fixed to the vehicle side to which it is attached. The body side bracket 101 can take various shapes according to the attachment structure to the vehicle side. 102 is the upper case, 104 is the fin for heat dissipation provided on the upper case 103, 105 is the connector, and 108 is the lower case for fixing the circuit board.

[0021] Figure 4 is a perspective view of the upper case 103 of the electronic control unit shown in Figure 3.

[0022] The screw mounting holes 105 of bracket 102 are visible. Insert screws into the screw mounting holes to fasten the body-side bracket 101. The connector opening 107 is the opening into which the connector fits when the upper case 103 is joined with the lower case 108.

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

[0024] The mounting surface of the bracket (mounting part) 102 is configured to be parallel to the opening direction of the connector opening 107. This configuration makes installation easier when installing the electronic control unit on the vehicle side, as the mounting direction of the connector and the mounting direction of the screws to the bracket 102 can be the same. Furthermore, since the work direction can be limited to one side, the workspace can be reduced, and it is expected that the degree of freedom in implementation, such as in retrofitting, will be improved.

[0025] Next, we will explain the manufacturing process of the upper case 103.

[0026] The upper case 103 is manufactured by die casting. The manufacturing method will be explained using Figure 5. The mold is divided and cast by pressing the fixed mold (core) 201 and the movable mold (cavity) 202 from above and below the upper case, while simultaneously pressing the pair of slide molds (core molds) 203 and 204 perpendicular to the connector opening.

[0027] In this case, the mounting surface of the bracket 102 can be changed in a 360-degree direction relative to the connector opening surface by changing the pressing surface angle of the slide mold.

[0028] Furthermore, while using a pair of slide molds makes it possible to ensure parallelism and flatness of the screw fastening surface of the bracket 102, die casting using a total of four molds can lead to increased manufacturing costs and complicated mold maintenance.

[0029] As a way to solve these problems, as shown in Figure 6, a slide mold 301 can be used only on the side that fastens the body-side bracket 101 to achieve precision, while the side that does not fasten the body-side bracket 101 can be configured such that the mold has a taper (draft taper) 302 that allows the cavity mold to exit. In that case, it is effective to surface-finish the tapered surface of the mounting part so that it is parallel to the opposing surface in order to eliminate the effect of the draft taper.

[0030] This will be explained using Figure 7. Figure 7(a) is a front view of the bracket 102, and Figure 7(b) shows the AA cross-section of Figure 7(a). As shown in Figure 7(b), it is effective to machine the surface of the body bracket 101 so that the contact surface is parallel to the opposing bolt (screw) fastening surface.

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

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

[0033] Figure 10 shows the manufacturing flow of the upper case 103 of the present invention. First, a release agent and lubricant are applied to the die-casting mold (step s100). Next, the core mold (a fixed mold), the cavity mold (a movable mold), and the slide mold for creating the bracket (in this diagram, there is one slide mold) are aligned to the pouring position (clamping: step s101). Molten aluminum is poured into the aligned molds (pouring: step s102). The cavity mold and slide mold are moved to inject and fill with molten metal (step s103). The mold is cooled while maintaining the pressure applied to it 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 (release / removal step s106). The 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 (s108). The upper case of the present invention is manufactured using the following process. <Comparative Example> Figure 11 shows a conventional electronic control unit. The connector openings are 2100, 3100, and 3200. The bracket is 600. In conventional electronic control units, the upper case was generally manufactured using only two molds, a cavity mold and a core mold, prioritizing ease of manufacturing. Therefore, the fastening surface of the bracket 600 was parallel to the circuit board (i.e., perpendicular to the connector opening surface).

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

[0035] Furthermore, when fastening screws, it was necessary to apply the screwdriver perpendicular to the longitudinal direction of the screw, meaning that the screwdriver had to be pointed in a different direction to fasten the screws. If the connector insertion direction and the screw fastening direction were different, the assembly of the electronic control unit into the vehicle would become complicated and require a considerable amount of workspace. [Explanation of symbols]

[0036] 10,100...Electronic control unit, 12...Circuit board, 13...Connector, 14...Internal space, 15...Enclosure, 20,120...First case, 21...Opening for connector, 22...Side opposite to the second case (top), 23...Rear side opposite the connector opening, 25...Boundary between top and rear, 27...Traces, 30...Second case, 40...Heat sink fins

Claims

1. A method for manufacturing an electronic control device comprising a housing having at least a bracket for mounting in a predetermined position and a connector opening, The housing is manufactured by die casting 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 horizontal to the pressing surface of the slide mold and is manufactured integrally with the housing. Furthermore, the method for manufacturing an electronic control device is characterized in that only one slide die is used, the mounting surface of the bracket that is not pressed by the slide die has a draft tapered surface of the cavity die, and the draft tapered surface is machined after demolding so that it becomes a surface parallel to and horizontal to the pressing surface of the slide die.

2. In the method for manufacturing an electronic control device according to claim 1, The method for manufacturing an electronic control device is characterized in that the cutting process involves cutting only the area near the fastening surface of the screw for fixing the bracket.

3. In the method for manufacturing an electronic control device according to claim 1, A method for manufacturing an electronic control device, characterized in that the bracket has a second mounting surface that is substantially perpendicular to the mounting surface having a surface horizontal to the pressing surface of the slide mold.

4. An electronic control device comprising a housing having at least a bracket for mounting in a predetermined position and a connector opening, The housing has a mounting surface for the bracket on a surface that is generally parallel to the connector opening, and is integrated with the housing. Furthermore, one of the mounting surfaces of the bracket has a tapered surface from the die-casting mold. The electronic control device is characterized in that the tapered surface of the die-casting mold is machined such that at least a portion of it is parallel to the other mounting surface of the bracket.

5. In the electronic control device according to claim 4, An electronic control device characterized in that the surface processed to be parallel to the other mounting surface of the bracket is only in the vicinity of the fastening surface of the screw for fixing the bracket.

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