Resin housing and electronic control device

Abstract

Provided are a resin housing that is capable of suppressing the warping that occurs when injection molded and keeping the weight down, and an electronic control device. A resin containing fibers is injection molded to form a housing shape for storing an electronic circuit board, and the resin housing has an opening to which an electronic component is connected. The resin housing has an opening formation wall plate that forms the opening, and a convex stepped part is formed on the outer side or the inner side in the opening formation wall plate.

Description

Resin housing and electronic control device

[0001] The present invention relates to a resin housing and an electronic control device.

[0002] The electronic control unit installed in a vehicle calculates the fuel injection amount, ignition timing, etc. to optimize fuel efficiency and power based on the air flow rate, temperature, pressure, etc. input from various sensors.The electronic control unit then generates control signals to be output to various electrical components such as the engine and transmission based on the fuel injection amount and ignition timing.

[0003] Conventionally, the housings and covers of electronic control units have often been made of sheet metal or aluminum die-cast. However, to improve fuel efficiency and reduce costs, electronic control units are required to be lighter and take up less space. Therefore, in recent years, thermoplastic resins such as polybutylene terephthalate, an engineering plastic, have increasingly been used for the housings and covers of electronic control units.

[0004] The housings and covers of electronic control devices require strength. For this reason, resins containing reinforcing fibers are used as the engineering plastics used to form the housings and covers. When resins containing reinforcing fibers are injection molded, the fibers become oriented in the resin as it flows through the product. This causes anisotropic shrinkage when the resin solidifies, resulting in warping of parts of the molded product.

[0005] A resin housing for an electronic control device has, for example, an opening-forming wall portion that forms an opening in which a connector is disposed. When the resin housing for an electronic control device is manufactured by injection molding a resin containing fiber, the housing shrinks when the resin changes from a molten state to a solidified state. This causes warping of the opening-forming wall portion. When warping occurs in the opening-forming wall portion, a gap occurs between the connector and the housing, resulting in a shortage of adhesive for bonding the connector and the housing and a decrease in the airtightness of the housing.

[0006] A technology for suppressing warpage that occurs in resin molded products is disclosed, for example, in Patent Document 1. The resin housing disclosed in Patent Document 1 has thick portions on the side walls to increase the degree of fiber orientation in the thick portions, which is expected to suppress warpage of the housing.

[0007] Japanese Patent Application Laid-Open No. 2022-64250

[0008] However, the resin housing disclosed in Patent Document 1 has thick portions on the side walls, which prevents the resin housing from being made lighter.

[0009] SUMMARY OF THE INVENTION In consideration of the above problems, an object of the present invention is to provide a resin housing and an electronic control device that can suppress warping that occurs during injection molding and that can suppress weight increase.

[0010] In order to achieve at least one of the above-mentioned objects, a resin housing according to one aspect of the present invention is formed by injection molding a fiber-containing resin into a housing shape for accommodating an electronic circuit board, and has an opening for connecting an electrical component. The resin housing has an opening-forming wall plate that forms the opening. The opening-forming wall plate has a step portion that is convex on either the outer surface or the inner surface.

[0011] An electronic control device according to the present invention includes an electronic circuit board, an electric component electrically connected to the electronic circuit board, and the resin housing described above.

[0012] The resin housing and electronic control device configured as described above can suppress warping that occurs during injection molding and can also be made lighter. Note that other issues, configurations, and effects will become clear from the description of the following embodiments.

[0013] 14 is a perspective view of an electronic control device according to a first embodiment. FIG. 15 is a cross-sectional view taken along line A-A in FIG. 1. FIG. 16 is a perspective view of a plastic housing according to the first embodiment. FIG. 17 is a cross-sectional view taken along line B-B in FIG. 3. FIG. 18 is a perspective view of a plastic housing in a conventional electronic control device. FIG. 19 is a cross-sectional view taken along line C-C in FIG. 5. FIG. 19 is a diagram illustrating a resin flow path within a mold and a plastic housing. FIG. 20 is a diagram illustrating fiber orientation and shrinkage anisotropy during injection molding. FIG. 21 is a diagram illustrating the resin flow and fiber orientation when injection molding a conventional plastic housing. FIG. 22 is a diagram illustrating the resin flow and fiber orientation when injection molding a plastic housing according to the first embodiment. FIG. 23 is a diagram illustrating the relationship between the height of a step portion in the plastic housing according to the first embodiment and the amount of warpage displacement at the center of an opening-forming wall panel. FIG. 24 is a diagram illustrating the relationship between the width of a step portion in the plastic housing according to the first embodiment and the amount of warpage displacement at the center of an opening-forming wall panel. FIG. 25 is a diagram illustrating the cross-sectional shapes and external forces of the opening-forming wall panels of a conventional plastic housing and the plastic housing according to the first embodiment. FIG. 26 is a cross-sectional view taken along line D-D in FIG. 25.

[0014] 1. First Embodiment An electronic control device according to a first embodiment of the present invention will be described below. Note that common members in each drawing are given the same reference numerals.

[0015] [Configuration of the Electronic Control Device] First, the configuration of the electronic control device according to the first embodiment will be described with reference to Figures 1 and 2. Figure 1 is a perspective view of the electronic control device according to the first embodiment. Figure 2 is a cross-sectional view taken along line A-A shown in Figure 1.

[0016] The electronic control unit 1 receives electrical signals from various sensors installed inside the automobile and detects conditions such as air flow rate, temperature, and pressure. The electronic control unit 1 also calculates the fuel injection amount, ignition timing, and other parameters to optimize fuel efficiency and power based on the air flow rate, temperature, pressure, and other parameters. The electronic control unit 1 then outputs control signals generated based on the fuel injection amount and ignition timing to various electrical components such as the engine and transmission.

[0017] As shown in FIGS. 1 and 2 , the electronic control device 1 includes a resin housing 100 , an electronic circuit board 200 , a connector 300 , and a base 400 .

[0018] The resin housing 100 and the base 400 form a hollow, flat housing 2. The housing 2 has an opening 3 on one side. The base 400 is formed into a plate shape using, for example, aluminum die-casting or sheet metal. The base 400 forms one side of the housing 2, and the resin housing 100 forms four sides of the housing 2.

[0019] Hereinafter, a direction substantially perpendicular to the opening 3 of the housing 2 will be referred to as a first direction Y. A direction substantially perpendicular to the first direction Y and parallel to the opening 3 will be referred to as a second direction X. A direction substantially perpendicular to the first direction Y and the second direction X will be referred to as a third direction Z. The third direction Z indicates the thickness direction of the flat housing 2.

[0020] The electronic circuit board 200 is disposed inside the housing 2. The electronic circuit board 200 is fixed to the base 400 using screws or adhesive. Electronic components such as a microcomputer, semiconductor chips, and capacitors are mounted on the electronic circuit board 200.

[0021] The connector 300 corresponds to an electrical component according to the present invention. The connector 300 passes through the opening 3 of the housing 2. The connector 300 has connector pins 301. The connector pins 301 of the connector 300 are electrically connected to the electronic circuit board 200 by soldering, press-fit connection, or the like.

[0022] The plastic housing 100 is fixed to the base 400 by thermal caulking, screws, or the like. The spaces between the plastic housing 100 and the base 400, between the connector 300 and the plastic housing 100, and between the connector 300 and the base 400 are sealed with a sealant such as an adhesive. This prevents the housing 2 from invading liquid, dust, and the like from the outside. As a result, the housing 2 protects the electronic circuit board 200 from liquid, dust, and the like.

[0023] [Configuration of the Plastic Housing] Next, the configuration of the plastic housing 100 will be described with reference to Fig. 3 and Fig. 4. Fig. 3 is a perspective view of the plastic housing 100. Fig. 4 is a cross-sectional view taken along line BB shown in Fig. 3.

[0024] 3 and 4 , the plastic housing 100 is formed in the shape of a housing with two openings. The plastic housing 100 has a first wall plate 101, a second wall plate 102, a third wall plate 103, and a fourth wall plate 104. The first wall plate 101 faces the base 400 in the third direction Z. The second wall plate 102 faces the third wall plate 103 in the second direction X. The fourth wall plate 104 faces the opening 3 in the first direction Y.

[0025] The first wall plate 101 corresponds to the opening-forming wall plate according to the present invention. One side of the first wall plate 101 in the first direction Y is an end surface 105 that forms the opening 3. The other side of the first wall plate 101 in the first direction Y is continuous with the fourth wall plate 104. The first wall plate 101 is formed with recesses 111 and 112 and a step 113 that is convex on the outer surface side.

[0026] The recesses 111 and 112 are located at the middle of the first wall panel 101 in the first direction Y. The recesses 111 and 112 are arranged side by side at an appropriate distance in the second direction X. One end of the recess 111 in the second direction X reaches the second wall panel 102. One end of the recess 112 in the second direction X reaches the third wall panel 103. By providing the recesses 111 and 112 in the plastic housing 100, the plastic housing 100 can be made into a polyhedron. As a result, it becomes easier to arrange additional shapes such as air intakes in the plastic housing 100.

[0027] The step portion 113 is located between the recesses 111, 112 and the end face 105. The step portion 113 has a rising piece 113a that protrudes approximately perpendicularly from the outer surface of the first wall panel 101 and a plate-like flat piece 113b that is parallel to the first wall panel 101. When viewed from the third direction Z, the flat piece 113b of the step portion 113 is formed into a rectangular shape that is long in the second direction X. The rising piece 113a is continuous with four sides of the flat piece 113b.

[0028] The thickness of the step 113 is set to be the same as the thickness of the other parts of the first wall panel 101. Therefore, providing the step 113 in the first wall panel 101 allows for a reduction in the amount of resin compared to providing the first wall panel 101 with a thicker part that is thicker than the other parts. As a result, the weight of the plastic housing 100 is suppressed. Furthermore, because the step 113 has a shape that is convex on the outer surface, interference with electronic components mounted on the electronic circuit board 200 can be avoided.

[0029] The plastic housing 100 is made of a fiber-containing engineering plastic. The plastic material of the plastic housing 100 is, for example, polybutylene terephthalate containing 30% glass fiber (GF). This allows the plastic housing 100 to be lighter than aluminum die-cast or sheet metal, and also reduces production costs. Furthermore, the plastic housing 100 can ensure the desired strength.

[0030] The plastic housing 100 is manufactured by injection molding. In injection molding, resin is injected through a first gate and a second gate of a mold. A first wall panel 101 of the plastic housing 100 has a first gate position 121 that faces the first gate of the mold, and a second gate position 122 that faces the second gate of the mold. Gate marks are formed at the first gate position 121 and the second gate position 122 of the first wall panel 101.

[0031] The first gate position 121 is located in the first direction Y between the end face 105 of the first wall panel 101 and the step 113. Therefore, during injection molding, the resin filled from the first gate advances toward the step 113. The second gate position 122 is located in the first direction Y between the end of the first wall panel 101 on the fourth wall panel side and the recesses 111 and 112.

[0032] [Configuration of a conventional plastic housing] Next, the configuration of a plastic housing in a conventional electronic control device will be described with reference to Figures 5 and 6. Figure 5 is a perspective view of the plastic housing in a conventional electronic control device. Figure 6 is a cross-sectional view taken along line CC shown in Figure 5.

[0033] A conventional electronic control device (not shown) includes a plastic housing 100A, an electronic circuit board 200, a connector 300, and a base 400. That is, the conventional electronic control device differs from the electronic control device 1 of this embodiment in the plastic housing 100A. As shown in Figures 5 and 6, the plastic housing 100A includes a first wall plate 101A, a second wall plate 102, a third wall plate 103, and a fourth wall plate 104.

[0034] The first wall panel 101A faces the base 400 in the third direction Z. One side of the first wall panel 101A in the first direction Y is an end surface 105. The other side of the first wall panel 101A in the first direction Y is continuous with the fourth wall panel 104. Recesses 111 and 112 are formed in the first wall panel 101A. In other words, the first wall panel 101A does not have a step 113 (see FIGS. 3 and 4 ).

[0035] The resin housing 100A is made of a fiber-containing engineering plastic. The resin housing 100A is manufactured by injection molding. During injection molding, resin is injected through a first gate and a second gate of a mold. A first wall panel 101A of the resin housing 100A has a first gate position 121 facing the first gate of the mold and a second gate position 122 facing the second gate of the mold. Gate marks are formed at the first gate position 121 and the second gate position 122 of the first wall panel 101A.

[0036] [Resin Flow Channel in Mold] Next, a flow channel through which resin flows inside the mold of the resin housing will be described with reference to Fig. 7. Fig. 7 is a diagram illustrating the resin flow channel in the mold and the resin housing.

[0037] The mold used for injection molding shown in Figure 7 is a two-point pin gate type. When the size of the housing is relatively large or when high precision is required for the shape, a multi-point gate type with two or more gates is used to compensate for pressure loss in the resin flow. When injection molding the plastic housing 100A, first, the injection unit in the injection molding machine injects plasticized resin at a predetermined pressure.

[0038] Resin injected from the injection molding machine passes through the resin flow paths in the mold, namely, sprue 151, runner 152, first gate 153, and second gate 154, and fills the gaps in the housing formation area. The filled resin is solidified through a cooling process. The mold is then opened, and the sprue 151, runner 152, first gate 153, and second gate 154 are separated from the solidified resin, and the molded product, resin housing 100A, is removed.

[0039] The plastic housing 100A thermally shrinks during the cooling process of injection molding and after the plastic housing 100A is removed from the mold. The amount of thermal shrinkage is not constant throughout the plastic housing 100A. The amount of thermal shrinkage at each location in the plastic housing 100A varies depending on differences in volume at each location in the plastic housing 100A, differences in the cooling rate at each location in the mold, and differences in the degree of fiber orientation contained therein. Because of the differences in the amount of thermal shrinkage at each location, warping (distortion) occurs, for example, in the first wall panel 101A of the plastic housing 100A.

[0040] If the warpage of the first wall panel 101A is large, gaps are formed between the plastic housing 100A and the connector 300, and between the plastic housing 100A and the base 400. As a result, various problems arise, such as imperfect adhesion between the plastic housing 100A and the connector 300, imperfect adhesion between the plastic housing 100A and the base 400, reduced assembly accuracy of the electronic control device, and increased stress at each fitting portion.

[0041] To suppress warpage in the conventional plastic housing 100A, the direction and amount of warpage of the injection-molded plastic housing 100A are first measured. Then, the type of warpage that will occur is predicted and the product dimensions in the mold are corrected.

[0042] [Fiber Orientation and Shrinkage Anisotropy] Next, fiber orientation and shrinkage anisotropy during injection molding will be described with reference to Fig. 8. Fig. 8 is a diagram for explaining fiber orientation and shrinkage anisotropy during injection molding.

[0043] 8, the shear force during injection molding causes a high proportion of the glass fiber fibers 161 contained in the resin to be oriented in the resin flow direction 162. That is, the longitudinal direction of the glass fiber fibers 161 is oriented approximately parallel to the resin flow direction 162. The strength of the glass fiber fibers 161 in the longitudinal direction is greater than the strength in the lateral direction.

[0044] Therefore, the shrinkage amount 163 in a direction parallel to the resin flow direction 162 is smaller than the shrinkage amount 164 in a direction perpendicular to the resin flow direction 162. This causes anisotropy in the shrinkage of the injection-molded resin, resulting in warpage in part of the resin molded product.

[0045] [Resin flow and fiber orientation when injection molding a resin housing] Next, the resin flow and fiber orientation when injection molding a resin housing will be described using Figures 9A and 9B and Figures 10A and 10B. Figures 9A and 9B are diagrams explaining the resin flow and fiber orientation when injection molding a conventional resin housing 100A. Figures 10A and 10B are diagrams explaining the resin flow and fiber orientation when injection molding the resin housing 100 of this embodiment.

[0046] 9A , when the resin housing 100A is injection molded, the resin is filled from the first gate position 121 of the first wall panel 101A and flows radially. The glass fiber strands are oriented in the same direction as the resin flow direction 170. This causes anisotropic shrinkage on the end surface 105 side of the first wall panel 101A.

[0047] As shown in FIG. 9B, when anisotropy in shrinkage occurs on the end surface 105 side of the first wall panel 101A, the first wall panel 101A warps so as to be convex on the inner side.

[0048] 10A , when the plastic housing 100 is injection molded, the resin is filled from the first gate position 121 of the first wall panel 101 and reaches the rising piece 113a of the step portion 113. The resin then flows in the second direction X along the rising piece 113a. The glass fiber fibers are then oriented in the same direction as the resin flow direction 180. This aligns the fiber orientation of the glass fiber fibers in the resin flow direction 180 (second direction X). As a result, shrinkage of the first wall panel 101 in the second direction X is suppressed.

[0049] 10B , suppressing the shrinkage of the first wall panel 101 in the second direction X suppresses warping of the first wall panel 101. As a result, the amount of warping (amount of displacement in the third direction Z) of the first wall panel 101 of the plastic housing 100 can be reduced compared to the first wall panel 101A of the conventional plastic housing 100A.

[0050] [Height of Step Portion and Displacement of Warpage] Next, the height of the step portion 113 and the displacement of the warpage at the center of the first wall panel 101 will be described with reference to Figures 11A and 11B. Figure 11A is a cross-sectional view showing the height of the step portion 113 in the plastic housing 100. Figure 11B is a graph illustrating the relationship between the height of the step portion 113 and the displacement of the warpage at the center of the first wall panel 101.

[0051] 11A , the distance in the third direction Z from the outer surface of the first wall panel 101 to the outer surface of the flat piece 113b of the step 113 is defined as the height t of the step 113. The amount of displacement in the third direction Z at the center of the first wall panel 101 in the second direction X is defined as the amount of warpage displacement h.

[0052] In this embodiment, the relationship between the height t of the step 113 and the amount of warpage displacement h was verified using a known resin flow simulation. In the resin flow simulation, the thickness of the first wall panel 101 (step 113) was set to 1.6 mm, and the length of the step 113 in the second direction X was set to the maximum length that can be formed on the first wall panel 101 (140 mm in this embodiment).

[0053] As shown in Figure 11B, increasing the height t of the step 113 reduces the warpage displacement h. Furthermore, when the height t of the step 113 exceeds 5 mm, the warpage displacement h remains almost unchanged. The results of this resin flow simulation revealed that if the height t of the step 113 is 50% or more of the thickness of the first wall panel 101 (step 113), the warpage displacement h can be reduced by approximately 0.5 mm. Therefore, it was found that if the height t of the step 113 is 50% or more of the thickness of the first wall panel 101, the warpage of the first wall panel 101 can be suppressed.

[0054] 12A and 12B , the length of the step 113 in the second direction X and the amount of warpage displacement at the center of the first wall panel 101 will be described. Fig. 12A is a cross-sectional view showing the width of the step 113 in the plastic housing 100. Fig. 12B is a graph illustrating the relationship between the width of the step 113 and the amount of warpage displacement at the center of the first wall panel 101.

[0055] 12A , the length of the step 113 in the second direction X is defined as the width w of the step 113. Furthermore, the amount of displacement in the third direction Z at the center of the first wall panel 101 in the second direction X is defined as the amount of warpage displacement h. The width w of the step 113 is the length of the rising piece 113a that the resin to be filled first reaches. In other words, the width w of the step 113 can also be considered the length of the portion that first changes the flow of the resin to be filled.

[0056] In this embodiment, the relationship between the width w of the step 113 and the amount of warpage displacement h was verified using a known resin flow simulation. In the resin flow simulation, the thickness of the first wall panel 101 (the step 113) was set to 1.6 mm, and the height t of the step 113 was set to 3.0 mm. The maximum length of the step 113 in the second direction X was set to 140 mm.

[0057] 12B , the results of the resin flow simulation showed that increasing the width w of the step 113 reduced the warpage displacement h. The results of this resin flow simulation showed that if the width w of the step 113 was 25% or more of the maximum length of the step 113 in the second direction X, the warpage displacement h was reduced by approximately 0.3 mm. Therefore, it was found that if the width w of the step 113 was 25% or more of the length of the first wall panel 101 in the second direction X, the warpage of the first wall panel 101 could be suppressed.

[0058] 11A and 11B and 12A and 12B, by appropriately setting the height t and width W of the step 113 formed in the first wall plate 101, it is possible to reduce the amount of warpage on the end surface 105 side of the first wall plate 101. That is, in this embodiment, the dimensions of the step 113 are parameterized to manufacture the mold parts for the plastic housing 100. As a result, in this embodiment, it is possible to easily correct the warpage of the first wall plate 101. Furthermore, in this embodiment, because the dimensions of the step 113 are parameterized, it is possible to reduce the number of mold modifications compared to conventional cases in which the mold is corrected based on the measurement results of the warpage of the molded product.

[0059] [Opening-Forming Wall Panel and External Force] Next, external forces acting on the conventional first wall panel 101A and the first wall panel 101 of this embodiment will be described with reference to Figures 13A and 13B. Figure 13A is a diagram showing the cross-sectional shape and external forces of the conventional first wall panel 101A. Figure 13B is a diagram showing the cross-sectional shape and external forces of the first wall panel 101 of this embodiment.

[0060] As shown in Fig. 13A, the conventional first wall panel 101A has a flat plate shape. On the other hand, as shown in Fig. 13B, the step 113 of the first wall panel 101 of this embodiment is formed in a substantially C-shape. That is, the step 113 has a rising piece 113a and a flat piece 113b.

[0061] Here, the plate thicknesses of the first wall panels 101 and 101A are set to the same (e.g., 1.6 mm), and the height t of the step 113 is set to 3 mm. The geometrical moment of inertia was calculated when an external force 190 is applied to the step 113 of the conventional first wall panel 101A and the first wall panel 101 of this embodiment. As a result, the geometrical moment of inertia of the step 113 of the first wall panel 101 was 2.3 times that of the conventional first wall panel 101A. Therefore, by forming the step 113 in the first wall panel 101, the strength of the first wall panel 101 can be improved.

[0062] 2. Second Embodiment An electronic control device according to a second embodiment of the present invention will be described below. Note that common members in each drawing are given the same reference numerals.

[0063] The electronic control device according to the second embodiment differs from the electronic control device 1 according to the first embodiment in the plastic housing 500. Therefore, here, a description of the configuration common to the electronic control device 1 in the second embodiment will be omitted, and the plastic housing 500 according to the second embodiment will be described.

[0064] [Configuration of Resin Housing] The configuration of the resin housing 500 will be described with reference to Fig. 14 and Fig. 15. Fig. 14 is a perspective view of the resin housing 500. Fig. 15 is a cross-sectional view taken along line DD shown in Fig. 14.

[0065] 14 and 15 , the plastic housing 500 is formed in the shape of a housing with two openings. The plastic housing 500 has a first wall plate 501, a second wall plate 102, a third wall plate 103, and a fourth wall plate 104. The first wall plate 501 faces the base 400 (see FIG. 1 ) in the third direction Z.

[0066] The first wall plate 501 corresponds to the opening-forming wall plate according to the present invention. One side of the first wall plate 501 in the first direction Y is an end surface 505 that forms the opening 3. The other side of the first wall plate 501 in the first direction Y is continuous with the fourth wall plate 104. The first wall plate 501 is formed with recesses 111 and 112 and a step 513 that is convex on the inner surface side.

[0067] The recesses 111 and 112 are located in the middle of the first wall panel 501 in the first direction Y. The recesses 111 and 112 are arranged side by side at an appropriate distance in the second direction X. One end of the recess 111 in the second direction X reaches the second wall panel 102. One end of the recess 112 in the second direction X reaches the third wall panel 103.

[0068] The step portion 513 is located between the recesses 111, 112 and the end face 505. The step portion 513 has a rising piece 513a that protrudes approximately perpendicularly from the inner surface of the first wall panel 101 and a plate-like flat piece 513b that is parallel to the first wall panel 101. When viewed from the third direction Z, the flat piece 513b of the step portion 513 is formed into a rectangular shape that is long in the second direction X. The rising piece 513a is continuous with four sides of the flat piece 513b.

[0069] The thickness of the step portion 513 is set to be the same as the thickness of the other portions of the first wall plate 501. Therefore, providing the step portion 513 in the first wall plate 501 allows for a reduction in the amount of resin compared to providing the first wall plate 501 with a thick portion that is thicker than the other portions. As a result, the weight of the plastic housing 500 is suppressed. Furthermore, the step portion 513 has a shape that is convex on the inner surface. Therefore, the length of the plastic housing 500 in the third direction Z is set so that the step portion 513 does not interfere with electronic components mounted on the electronic circuit board 200 (see FIG. 2 ).

[0070] The resin housing 500 is made of a fiber-containing engineering plastic. This allows the resin housing 500 to be lighter than aluminum die-cast or sheet metal housings, and also reduces production costs. Furthermore, the resin housing 500 can ensure the desired strength.

[0071] The plastic housing 500 is manufactured by injection molding. The first wall panel 101 of the plastic housing 100 has a first gate position 121 facing the first gate of the mold and a second gate position 122 facing the second gate of the mold. The first gate position 121 is located between the end face 505 of the first wall panel 501 and the step portion 113 in the first direction Y. The second gate position 122 is located between the end of the first wall panel 501 on the fourth wall panel side and the recesses 111, 112 in the first direction Y. Gate marks are formed at the first gate position 121 and the second gate position 122 of the first wall panel 101.

[0072] In the plastic housing 500 according to the second embodiment, as in the first embodiment, the fiber orientation of the glass fiber fibers is aligned in the resin flow direction (second direction X). This suppresses shrinkage of the first wall panel 101 in the second direction X, thereby suppressing warping of the first wall panel 501. As a result, the amount of warping (amount of displacement in the third direction Z) of the first wall panel 101 of the plastic housing 100 can be reduced compared to the first wall panel 101A of the conventional plastic housing 100A. Furthermore, because the step portion 513 is convex toward the inner surface of the first wall panel 501, the plastic housing 500 can be made smaller.

[0073] The present invention is not limited to the embodiments described above and shown in the drawings, and various modifications are possible within the scope of the invention as defined in the claims. Furthermore, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is 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.

[0074] In this embodiment, the step 113, 513 has a rectangular shape when viewed from the third direction Z. However, the planar shape of the step according to the present invention is not limited to a rectangle and may be other shapes, such as an arc or a triangle. However, to suppress warping in a resin housing, it is preferable to form a step having a raised piece that changes the resin flow direction to the second direction X. This aligns the fiber orientation in the second direction X, thereby suppressing shrinkage of the first wall panel (the opening-forming wall panel) in the second direction X. As a result, the amount of warping (displacement in the third direction Z) of the first wall panel can be reduced.

[0075] DESCRIPTION OF SYMBOLS 1...Electronic control device, 2...Housing, 3...Opening, 100, 500...Resin housing, 101, 501...First wall plate, 102...Second wall plate, 103...Third wall plate, 104...Fourth wall plate, 105, 505...End face, 111, 112...Recess, 113, 513...Step portion, 113a...Rising piece, 113b...Flat plate piece, 121...First gate position, 122...Second gate position, 151...Sprue, 152...Runner, 153...First gate, 154...Second gate, 161...Glass fiber fabric, 162, 170, 180...Flow direction, 163, 164...Contraction amount, 190...External force, 200...Electronic circuit board, 300...Connector, 301...connector pin, 400...base

Claims

1. A resin housing formed by injection molding a fiber-containing resin into a housing shape for housing an electronic circuit board, the resin housing having an opening for connecting an electrical component, the resin housing having an opening-forming wall plate that forms the opening, the opening-forming wall plate having a step portion that is convex on the outer surface or the inner surface.

2. The plastic housing according to claim 1, further comprising a gate mark between the end face of the opening and the step.

3. The plastic housing according to claim 2, wherein the opening-forming wall plate has at least one second gate mark in a region opposite the end face of the opening with respect to the step portion.

4. The plastic housing according to claim 1, wherein the thickness of the step is the same as the thickness of the opening-forming wall plate.

5. The plastic housing according to claim 1, wherein the height of the step is set to 50% or more of the plate thickness of the step.

6. The plastic housing according to claim 1, wherein, when the direction connecting the end face of the opening and the step and the direction perpendicular to the height direction of the step are defined as the width direction, the length of the step in the width direction is set to 25% or more of the maximum length that can be formed in the opening-forming wall plate.

7. The plastic housing according to claim 3, wherein a groove is formed between the step and the second gate mark.

8. An electronic control device comprising: an electronic circuit board; an electrical component electrically connected to the electronic circuit board; and a resin housing formed by injection molding of a fiber-containing resin into a housing shape for housing the electronic circuit board, the resin housing having an opening to which the electrical component is connected, the resin housing having an opening-forming wall plate which forms the opening, the opening-forming wall plate having a step portion which is convex on either the outer surface or the inner surface.

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