Mold and method for producing molded article

Abstract

The present invention relates to a mold (10) that is made from a plate-shaped member which exhibits flexibility, and a method for producing a molded article (50) that uses such a mold (10), wherein the mold (10) has a cavity (22) for obtaining the molded article (50), and a fragile portion (24) that intermittently or continuously extends along an inner surface which defines the cavity (22) or a surface which is on the rear side with respect to the inner surface.

Description

Mold and Method for Manufacturing a Molded Product

[0001] The present invention relates to a mold and a method for manufacturing a molded product.

[0002] In recent years, in vehicles such as automobiles, an electronic control unit for controlling the operating state of an internal combustion engine or an electric motor as a drive source, the operating state of vehicle-mounted components, etc. has come to be used. In such an electronic control unit or the like, in order to protect a circuit board, electronic components, etc., it is common to adopt a configuration in which the surroundings thereof are covered with resin.

[0003] Under such circumstances, Patent Document 1 relates to a method for manufacturing an electronic circuit block. In its conventional example, using a resin receiving container 16, with a part of a substrate 4 inserted into the resin receiving container 16, resin 5 is poured into the resin receiving container 16 from the upper opening so that the liquid level of the resin 5 reaches the position where the electronic components 3 mounted on the substrate 4 are sealed. At this time, only the portion where the high-voltage electronic component 3a among the electronic components 3 mounted on the substrate 4 is mounted is located below the liquid level of the resin 5, and the low-voltage electronic component 3b is located above the liquid level of the resin 5. After the resin 5 is solidified or cured in this state, the electronic circuit block is disclosed to be demolded from the resin receiving container 16.

[0004] Japanese Patent Application Laid-Open No. 2001-210960

[0005] However, according to the study by the present inventor, in the configuration of Patent Document 1, the resin receiving container 16 is used as a mold for mold molding, and resin 5 is molded at the location where the high-voltage electronic component 3a of the substrate 4 is mounted, and an electronic circuit block in which the electronic component 3a is sealed with the resin 5 is obtained. Therefore, although a simple configuration in which a housing surrounding the resin 5 becomes unnecessary is realized, since the electronic circuit block and the resin receiving container 16 are in close contact, it is not easy to demold and remove the electronic circuit block from the resin receiving container 16, and there is room for improvement in this regard. Further, in such a case, when the resin receiving container 16 is made of a flexible plate-like member, it becomes more difficult to separate the mutually-adhered electronic circuit block and the resin receiving container 16, so the tendency that it is even more difficult to demold and remove the electronic circuit block from the resin receiving container 16 is strengthened, and there is also room for improvement in this regard.

[0006] This invention was made after the above considerations, and aims to provide a mold and a method for manufacturing molded products that can reliably release molded products with a simplified configuration.

[0007] To achieve the above objectives, the present invention is a mold made of a flexible plate-shaped member for obtaining a molded product, wherein the mold has a cavity for obtaining the molded product, and has a weak portion that extends intermittently or continuously on the inner surface defining the cavity or on the surface on the back side of the inner surface.

[0008] Furthermore, the present invention provides a method for manufacturing a molded product comprising: a first step of obtaining a molded product having a shape that conforms to the shape of a cavity in a mold made of a flexible plate-like member; and a second step of removing the molded product from the cavity, wherein the mold has a weak portion that extends intermittently or continuously on the inner surface defining the cavity or on the surface on the back side of the inner surface, and in the second step, when the mold is split along the weak portion, the molded product is removed from the cavity as another aspect.

[0009] According to one aspect of the present invention, the mold, which is made of a flexible plate-like member, has a cavity for obtaining a molded product, and also has a weak portion that extends intermittently or continuously on the inner surface defining the cavity or on the surface on the back side of the inner surface. Therefore, the molded product can be reliably released from the mold with a simplified structure.

[0010] Furthermore, according to another aspect of the present invention, in the first step, a molded product having a shape that conforms to the shape of the cavity of a mold made of a flexible plate-like member is obtained, and in the second step, in which the molded product is removed from the cavity, the mold is split along the weak part to remove the molded product from the cavity. Thus, the molded product can be reliably released from the mold with a simplified configuration.

[0011] Figure 1 is a front view of the mold in an embodiment of the present invention. Figure 2 is a top view of the mold in this embodiment. Figure 3 is a cross-sectional view taken along line A-A in Figure 2. Figure 4 is an enlarged cross-sectional view of portion B in Figure 3. Figure 5 is a cross-sectional view of the electronic control device applied to this embodiment, and its position corresponds to that of Figure 3. Figure 6 is a front view of the mold in this embodiment showing the state in which the device body is positioned within the mold. Figure 7 is a front view of the mold in this embodiment showing the state in which the mold has been split after the resin material injected into the mold has solidified or hardened.

[0012] The method for manufacturing molds and molded products according to embodiments of the present invention will be described in detail below, with appropriate reference to the drawings. In the drawings, the x, y, and z axes form a three-axis orthogonal coordinate system, where the x-axis direction is the width direction and the rightward direction is the positive direction of the x-axis, the y-axis direction is the front-back direction and the rearward direction is the positive direction of the y-axis, and the z-axis direction is the up-down direction and the upward direction is the positive direction of the z-axis.

[0013] Figure 1 is a front view of the mold in an embodiment of the present invention. Figure 2 is a top view of the mold in this embodiment. Figure 3 is a cross-sectional view taken along line A-A in Figure 2. Figure 4 is an enlarged cross-sectional view of portion B in Figure 3. Figure 5 is a cross-sectional view of an electronic control device applied to this embodiment, and its position corresponds to that in Figure 3.

[0014] As shown in Figure 1, the mold 10 in this embodiment is typically made of a flexible and breakable plate-like material such as synthetic resin, and is a container-like member into which potting resin material can be injected from an opening at one end and accommodated. Specifically, the mold 10 has a front wall 11 which is a wall portion defined in the left-right and up-down directions on the front side in the front-rear direction, a rear wall 13 which is a wall portion facing the front wall 11 on the rear side in the front-rear direction, a right wall 16 which is a wall portion defined in the front-rear and up-down directions on the right side in the left-right direction, a left wall 17 which is a wall portion facing the right wall 16 on the left side in the left-right direction, a bottom wall 19 which is a wall portion that closes the lower ends of the front wall 11, rear wall 13, right wall 16 and left wall 17 in the up-down direction, and an opening 21 which opens the upper ends of the front wall 11, rear wall 13, right wall 16 and left wall 17 in the up-down direction. Inside the mold 10, a cavity 22 is defined, surrounded by a front wall 11, a rear wall 13, a right wall 16, and a left wall 17, with its lower end closed by a bottom wall 19, and its upper end communicating with the outside through an opening 21. The cavity 22 has an inner surface 23 that defines its shape. The number of walls in the mold 10 may be less than 5 or more than 5, and the shape of the walls in the mold 10 may be planar or curved, with their periphery having any desired contour.

[0015] More specifically, mold 10 has a recess 24 in which the wall surface of the front wall 11 is indented, reducing the thickness of the front wall 11. Typically, such a recess 24 has a bottom portion 25 which is a flat portion in which the wall surface of the front wall 11 is recessed, and a connecting portion 26 which is an inclined peripheral wall portion that connects the front wall 11 and the bottom portion 25, and functions as a weak point where the front wall 11 breaks when a tensile force is applied to the front wall 11. For example, when an external force is applied to the front wall 11 such that a tensile force acting to the right in the left-right direction and a tensile force acting to the left in the left-right direction are applied, the recess 24 is pulled to the left and right, stress concentrates in the recess 24, and as a result the front wall 11 breaks starting from the recess 24. From the viewpoint of not leaving any trace of the recess 24 on the surface of the potting resin body 58 of the electronic control device 50, which will be described in detail later, it is preferable that the recess 24 is a recess formed by recessing the outer wall surface of the front wall 11 (the outer wall surface opposite to the inner surface 23 of the housing section 22) inward (towards the inner surface 23). Furthermore, if multiple recesses 24 are provided intermittently (discontinuously), and these multiple recesses 24 are arranged as a series of recesses that extend vertically in a dotted line-like manner, then when such an external force is applied, the front wall 11 will break horizontally, exhibiting a linear fracture starting from the multiple linear recesses 24, and the mold 10 will be split. From the viewpoint of making it easier to split the mold 10, it is preferable that these multiple recesses 24 extend vertically between the bottom wall 19 and the opening 21, connecting them. Furthermore, from the viewpoint of making it easier to cut the mold 10, the multiple recesses 24 may be provided as two or more rows of recesses that are arranged parallel to each other at a predetermined distance apart in the left-right direction on the front wall 11 and extend in the vertical direction. The figure shows an example in which two rows of recesses 24, 24 are provided. In addition to being provided on the front wall 11, or not provided on the front wall 11, the recesses 24 may be provided on at least one of the rear wall 13, right wall 16, left wall 17, and bottom wall 19. Alternatively, instead of providing multiple recesses 24 in a dotted line shape, the recesses 24 may be formed in a continuous groove shape, and these groove-shaped recesses 24 may be arranged as a recess groove that extends in a continuous line shape in the vertical direction. As for the location where the recesses 24 are provided, from the viewpoint of making it easier to cut the mold 10, a wall portion that has a single flat surface and a relatively large area, that is, the front wall 11 in the configuration of this embodiment, is preferred.

[0016] Furthermore, from the viewpoint of improving the strength of the front wall 11 and improving the grip of the worker, a protrusion 12, which is a thickened portion extending in the left-right direction, may be provided at the upper end of the front wall 11. In this case, the recess 24 will also be provided on the protrusion 12, and when the front wall 11 is fractured to the left and right at the recess 24 provided on the front wall 11 other than the protrusion 12, the front wall 11 will also be fractured to the left and right at the recess 24 provided on the protrusion 12.

[0017] Here, the electronic control device 50 housed in the mold 10 is typically a control device such as an ECU (Electronic Control Unit) that controls the operating state of a drive source such as an internal combustion engine or electric motor of a vehicle such as an automobile. For example, it includes a circuit board 51 such as a printed circuit board, a CPU (Central Processing Unit) mounted on the front and back surfaces of the circuit board 51, various electronic components 53 such as memory and capacitors, a connector 55 to which a plurality of pin terminals 56 are attached for electrically connecting the circuit board 51 and other components and external connection devices (not shown), and a potting resin body 58.

[0018] The potting resin body 58 is a filler that, when a resin material such as epoxy resin or silicone resin is injected into the housing 22 through an opening 21 around the main body of the device C (shown in the figure as an assembly consisting of a circuit board 51, electronic components 53, and a connector 55) positioned and placed in the housing 22 of the mold 10, and then solidifies or hardens the resin material in a predetermined environment, embeds the entire circuit board 51 and electronic components 53 within the potting resin body 58, while embedding only a portion of the connector 55 on the side of the circuit board 51 and electronic components 53 within the potting resin body 58. Furthermore, for example, if the electronic components 53 of the electronic control device 50 are arranged such that the electronic components 53 further away from the connector 55 are less bulky, it becomes possible to reduce the thickness of the potting resin body 58 on the side further away from the connector 55. Accordingly, it is also possible to arrange the upper rear wall 14, which is the wall portion of the rear wall 13 on the connector 55 side, parallel to the front wall 11, while setting the lower rear wall 15, which is the side of the rear wall 13 further away from the connector 55, as an inclined wall that slopes towards the circuit board 51 as it moves downward from the upper rear wall 14.

[0019] An example of a manufacturing method for producing an electronic control device 50 using the mold 10 having the above configuration will be described in detail below with reference to Figures 6 and 7.

[0020] Figure 6 is a front view of the mold 10 showing the device body C positioned within the mold 10 in this embodiment. Figure 7 is a front view of the mold 10 after it has been split apart following the solidification or hardening of the resin material injected into the mold 10 in this embodiment. In the figures, the recesses 24 are exemplified as rows of recesses 24 arranged in two parallel rows in the left-right direction and extending intermittently (discontinuously) in the vertical direction.

[0021] First, as shown in Figure 6, the device body C is positioned relative to the mold 10 so that it is in a predetermined position within the housing 22, with a portion of the connector 55 on the side furthest from the circuit board 51 exposed to the outside of the housing 22. Then, a predetermined amount of resin material (not shown) is injected through the gap in the opening 21 between the device body C and the housing 22 in this positioned state, so that the entire circuit board 51 and electronic components 53 are embedded in the resin material, and only a portion of the connector 55 on the side facing the circuit board 51 and electronic components 53 is embedded in the resin material. Next, with the filling complete, a predetermined time is allowed to pass under predetermined environmental conditions to allow the resin material filled between the device body C and the housing 22 to solidify or harden sufficiently.

[0022] Next, as shown in Figure 7, with the resin material filled between the main body C and the housing 22 sufficiently solidified or hardened, an external force F is applied to the front wall 11, for example, such that a tensile force acting to the right in the left-right direction and a tensile force acting to the left in the left-right direction are applied, pulling the front wall 11 to the left and right and concentrating stress in the row of recesses 24. As a result, the mold 10 is split by the front wall 11 breaking starting from the row of recesses 24, and the electronic control device 50 is removed from the mold 10 with the constraint of the housing 22 of the mold 10 gone. At this time, the shape of the potting resin body 58 is molded to match the shape of the housing 22 of the mold 10. Alternatively, when removing the electronic control device 50 from the mold 10, an external force may be applied that applies tensile forces F in opposite directions to the front wall 11 in the left-right direction, and an external force may be applied that pulls the portion of the front wall 11 between the row of recesses 24 in the left-right direction toward the front, away from the electronic control device 50.

[0023] In the first aspect of the mold 10 in this embodiment described above, the mold 10, which is made of a flexible plate-shaped member, has a cavity 22 for obtaining a molded product 50, and also has a fragile portion 24 that extends intermittently or continuously on the inner surface 23 defining the cavity 22 or on the surface on the back side of the inner surface 23. Therefore, the molded product 50 can be reliably released from the mold with a simplified configuration.

[0024] Furthermore, in the second aspect of the mold 10 in this embodiment, the fragile portion 24 is a recess 24 provided in the member of the mold 10, and the recess 24 extends in the direction connecting the opening 21 side of the cavity 22 and the bottom 19 side of the cavity 22, so that the molded product 50 can be easily and reliably removed from the cavity 22.

[0025] Furthermore, in the third aspect of the mold 10 in this embodiment, the weak portion 24 is a recess 24 provided in the member of the mold 10, and since the recess 24 extends intermittently, the cost of the mold 10 can be reduced compared to a configuration in which the recess 24 extends continuously.

[0026] Furthermore, in the fourth aspect of the mold 10 in this embodiment, the weak portion 24 is a recess 24 provided in the member of the mold 10, and the recess 24 is formed on the back surface relative to the inner surface 23 that defines the cavity 22. Therefore, it is possible to suppress the formation of unnecessary recess 24 marks on the surface of the molded product 50 during molding.

[0027] Furthermore, in the fifth aspect of the mold 10 in this embodiment, since the molded product 50 includes a resin component 58, a mold 10 suitable for such a configuration can be realized even if the molded product 50 includes a resin component 58.

[0028] Furthermore, in the sixth aspect of the mold 10 in this embodiment, the weak portion 24 is a recess 24 provided in the member of the mold 10, and the recess 24 is provided as a first plurality of recesses 24 and a second plurality of recesses 24, and the first plurality of recesses 24 and the second plurality of recesses 24 extend parallel to each other, so the number of rows where stress is concentrated increases, and the mold 10 can be split easily and reliably.

[0029] Furthermore, in the seventh aspect of the mold 10 in this embodiment, the cavity 22 communicates with the outside through the opening 21, so that resin material can be reliably supplied to the cavity 22, thereby improving the productivity of molded products 50 and realizing a low-cost mold 10.

[0030] Furthermore, in another aspect of the mold manufacturing method of this embodiment, a molded product 50 having a shape that conforms to the shape of the cavity 22 of the mold 10, which is made of a flexible plate-like material, is obtained in the first step. In the second step, when the mold 10 is split along the weak part 24, the molded product 50 is removed from the cavity 22. Thus, the molded product 50 can be reliably released from the mold with a simplified configuration.

[0031] The present invention is not limited to the above-described embodiments in terms of the type, shape, arrangement, number, etc. of the components, and it is of course possible to modify them as appropriate without departing from the spirit of the invention, such as by appropriately substituting the components with those that produce equivalent effects.

[0032] As described above, the present invention provides a mold and a method for manufacturing molded products that can reliably release molded products with a simplified configuration. Due to its general-purpose and universal nature, it is expected to be widely applicable to molds for manufacturing vehicle molded products and methods for manufacturing molded products using the same.

[0033] 10...Mold 11...Front wall 12...Protrusion 13...Rear wall 14...Upper rear wall 15...Lower rear wall 16...Right wall 17...Left wall 19...Bottom wall 21...Opening 22...Accommodation section (cavity) 23...Inner surface 24...Recess (row of recesses) 25...Bottom 26...Connecting section 50...Electronic control unit 51...Circuit board 53...Electronic components 55...Connector 56...Pin terminal 58...Potting resin

Claims

1. A mold made of a flexible plate-shaped member for obtaining a molded product, wherein the mold has a cavity for obtaining the molded product, and is characterized in that it has a weak portion that extends intermittently or continuously on the inner surface defining the cavity or on the surface on the back side of the inner surface.

2. The mold according to claim 1, characterized in that the weak portion is a recess provided in the member, and the recess extends in a direction connecting the opening side of the cavity and the bottom side of the cavity.

3. The mold according to claim 1, wherein the weak portion is a recess provided in the member, and the recess extends intermittently.

4. The mold according to claim 1, wherein the weak portion is a recess provided in the member, and the recess is formed on the back surface.

5. The mold according to claim 1, characterized in that the molded product includes resin parts.

6. The mold according to claim 1, wherein the weak portion is a recess provided in the member, the recess is provided as a first plurality of recesses and a second plurality of recesses, and the first plurality of recesses and the second plurality of recesses extend parallel to each other.

7. The mold according to any one of claims 1 to 6, characterized in that the cavity communicates with the outside through an opening.

8. A method for manufacturing a molded article, comprising: a first step of obtaining a molded article having a shape that conforms to the shape of a cavity in a mold made of a flexible plate-like member; and a second step of removing the molded article from the cavity, wherein the mold has a weak portion that extends intermittently or continuously on the inner surface defining the cavity or on the surface on the back side of the inner surface, and in the second step, when the mold is split along the weak portion, the molded article is removed from the cavity.

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