Electronic device

Abstract

To provide a technology suitable for countering electromagnetic noise by utilizing metal contact between a circuit board and a housing.SOLUTION: An exemplary electronic device includes a circuit board carrying electronic components and a metal housing that houses the circuit board. The housing has an inner wall on which the circuit board is placed and that surrounds the electronic components, and a protrusion that is provided on a surface of the inner wall facing the circuit board and that makes metallic contact with the circuit board.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an electronic device including a circuit board on which electronic components are mounted. [Background technology]

[0002] Conventionally, there is known a technique for reducing the influence of electromagnetic waves on circuit components in electronic devices (see, for example, Patent Document 1). Patent Document 1 discloses that by providing an antenna element at a distance from a circuit board, it is possible to reduce the influence of noise on circuit components due to radio wave radiation from the antenna element. In Patent Document 1, the antenna element is disposed on the bottom surface of the housing. The circuit board is disposed on a rib provided on the bottom surface of the housing, and is therefore disposed at a distance from the antenna element in a direction perpendicular to the circuit board. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-79200 Summary of the Invention [Problem to be solved by the invention]

[0004] As a method different from the configuration of Patent Document 1, it is possible to block electromagnetic noise by utilizing metallic contact between the circuit board and the housing that the circuit board is placed in. In such a configuration, in order to reliably obtain metallic contact between the circuit board and the housing at a desired position, it is conceivable to use a configuration in which a leaf spring is arranged or a configuration in which screws are used for fixing, for example.

[0005] However, if a leaf spring or screw is placed at each location where metal contact between the circuit board and the housing is desired, the number of leaf springs and screws used will increase, raising concerns about increased manufacturing costs for electronic devices. Furthermore, a configuration using leaf springs and screws requires a large area for arranging these components, raising concerns about increased dead space on the circuit board. Large dead space reduces the efficiency of electronic component placement on the circuit board.

[0006] In view of the above, an object of the present invention is to provide a technique suitable for suppressing electromagnetic noise by utilizing metallic contact between a circuit board and a housing. [Means for solving the problem]

[0007] An exemplary electronic device of the present invention includes a circuit board on which electronic components are mounted, and a metal housing that houses the circuit board. The housing has an inner wall on which the circuit board is mounted and that surrounds the electronic components, and a protrusion that is provided on a surface of the inner wall facing the circuit board and that makes metallic contact with the circuit board. [Effects of the Invention]

[0008] According to the exemplary embodiment of the present invention, a protrusion on the inner wall of a housing can be used to facilitate metallic contact between the inner wall and a circuit board placed on the inner wall at a targeted position. This configuration can minimize the number of leaf springs and screws used to achieve metallic contact between the housing and the circuit board. This minimizes the amount of dead space on the circuit board that would otherwise be created by the placement of leaf springs and screws. In other words, the exemplary embodiment of the present invention can provide a technology suitable for electromagnetic noise countermeasures that utilizes metallic contact between a circuit board and a housing. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view showing a schematic configuration of an electronic device; [Figure 2] FIG. 2 is an exploded perspective view of the electronic device shown in FIG. 1. [Figure 3]FIG. 1 is a perspective view showing a schematic configuration of a housing of an electronic device; [Figure 4] FIG. 1 is a plan view showing a schematic configuration of a housing provided in an electronic device; [Figure 5] Schematic cross-sectional view at the VV position in Figure 1 [Figure 6] Schematic cross-sectional view taken along the line VI-VI in Figure 1. [Figure 7] Schematic cross-sectional view taken along line VII-VII in Figure 1. [Figure 8] 10 is a schematic cross-sectional view illustrating pin marks formed on a partition wall shown as a comparative example to the first partition wall of the present embodiment; FIG. [Figure 9] FIG. 10 is a cross-sectional view showing a schematic configuration of a protrusion provided on an inner wall. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. The drawings appropriately show an XYZ coordinate system configured as a three-dimensional Cartesian coordinate system. In the following description, the X direction is the front-to-back direction, the Y direction is the left-to-right direction, and the Z direction is the up-down direction. Furthermore, the +X side is the front side, and the -X side is the rear side. The +Y side is the right side, and the -Y side is the left side. The +Z side is the top side, and the -Z side is the bottom side. However, these directions are names used merely for the purpose of explanation, and are not intended to limit the actual positional relationships and directions.

[0011] In the XYZ coordinate system, the main surface direction of the circuit board 2 (see FIG. 2, etc.) described below is the XY plane direction, and the thickness direction of the circuit board 2 is the Z direction. The "main surface" refers to the main surfaces on the front and back of the circuit board 2 excluding the side surfaces that are surfaces along the thickness direction of the circuit board 2, and the "main surface direction" refers to the direction parallel to the main surface.

[0012] <1. Overview of the electronic device> FIG. 1 is a perspective view showing a schematic configuration of an electronic device 100 according to an embodiment of the present invention. FIG. 2 is an exploded perspective view of the electronic device 100 shown in FIG. 1. The electronic device 100 is an ECU (Electronic Control Unit) mounted on a vehicle (not shown). The ECU controls electronic devices mounted on the vehicle. However, the electronic device of the present invention is not limited to an ECU, and may be other electronic devices. Furthermore, the electronic device of the present invention may be an electronic device mounted on something other than a vehicle.

[0013] As shown in Figures 1 and 2, the electronic device 100 includes a housing 1, a circuit board 2, and a cover 3. The housing 1 is box-shaped with an opening 1a on the top surface. The housing 1 has the circuit board 2 disposed therein. In other words, the circuit board 2 is housed within the housing 1. The cover 3 is disposed above the circuit board 2 disposed within the housing 1 and covers the circuit board 2. The cover 3 is made of metal, and more specifically, is formed from a pressed material obtained by pressing a metal plate. The circuit board 2 and the cover 3, which are disposed one above the other in the vertical direction, are fixed to the housing 1 using a plurality of fastening members 4. More specifically, the fastening members 4 are screws. The circuit board 2 and the cover 3 are fastened together to the housing 1 using the fastening members 4.

[0014] The circuit board 2 is a plate-like member extending in the XY plane. Electronic components 21 (see FIG. 5, etc., described later) are mounted on the circuit board 2. The electronic components 21 include various electronic components including IC (Integrated Circuit) chips. A connector 22 is also attached to the circuit board 2. That is, the electronic device 100 includes the connector 22 attached to the circuit board 2. The connector 22 enables electrical connection with an external device.

[0015] In detail, the connector 22 includes a power connector 221 and a signal connector 222. The power connector 221 is connected to a power line (not shown) that supplies power from the power source. The power line is, for example, a power cable that is electrically connected to a power supply device. By providing the power connector 221, power from the power source can be supplied to the circuit board 2.

[0016] The signal connector 222 is connected to a signal line (not shown) that transmits a signal. The signal line is, for example, a signal cable that connects a signal transmitting device that transmits signals and a signal receiving device that receives signals, both of which are provided outside the electronic device 100. The signal transmitting device and the signal receiving device may be configured as a single device that transmits and receives signals. The provision of the signal connector 222 allows signals to be input from the outside to the circuit board 2 and signals to be output from the circuit board 2 to the outside.

[0017] 2. Electromagnetic noise blocking structure Next, the electromagnetic noise blocking structure in the electronic device 100 configured as above will be described.

[0018] [2-1. Overview] FIG. 3 is a perspective view showing a schematic configuration of the housing 1 provided in the electronic device 100. FIG. 4 is a plan view showing a schematic configuration of the housing 1 provided in the electronic device 100. The housing 1 is made of metal. The housing 1 is a molded part. More specifically, the housing 1 is a die-cast molded part. More specifically, the housing 1 is an aluminum die-cast molded product made using an aluminum alloy.

[0019] As shown in Figures 3 and 4, the housing 1 is rectangular in plan view. In plan view, the housing 1 has a rectangular bottom wall 11 and a rectangular frame-shaped outer peripheral wall 12. The outer peripheral wall 12 extends upward from the outer peripheral portion of the upper surface of the bottom wall 11. Specifically, the outer peripheral wall 12 includes a front outer wall 12a, a rear outer wall 12b, a left outer wall 12c, and a right outer wall 12d. The front outer wall 12a extends upward from the front end of the upper surface of the bottom wall 11. The rear outer wall 12b extends upward from the rear end of the upper surface of the bottom wall 11. The left outer wall 12c extends upward from the left end of the upper surface of the bottom wall 11. The right outer wall 12d extends upward from the right end of the upper surface of the bottom wall 11.

[0020] Two connector openings 121 that expose the power connector 221 and the signal connector 222 to the outside are provided in the front outer wall 12a. The two connector openings 121 are aligned with a gap in the left-right direction. More specifically, each connector opening 121 is configured by cutting out a certain rectangular range including the upper end of the front outer wall 12a when viewed from the front, and the outer peripheral wall 12 is not present in the portion where the connector opening 121 is provided. The cutout range (certain range) is changed as appropriate to match the size of the connector 22. In this embodiment, the power connector 221 and the signal connector 222 are different sizes, so the two connector openings 121 are different in size.

[0021] 3 and 4, the housing 1 has an internal wall 13 therein. The circuit board 2 is placed on the internal wall 13. The internal wall 13 extends upward from the upper surface of the bottom wall 11, similar to the outer peripheral wall 12. However, the upper surface of the internal wall 13 is located lower (below) than the upper surface of the outer peripheral wall 12. In FIG. 4, the hatched area corresponds to the upper surface of the internal wall 13. Because the upper surface of the internal wall 13 is located lower than the upper surface of the outer peripheral wall 12, the circuit board 2 placed on the internal wall 13 is disposed inside the housing 1.

[0022] A portion of the inner wall 13 protrudes from the outer peripheral wall 12 toward the interior of the housing 1. The inner wall 13 includes a front inner wall 13a, a rear inner wall 13b, a left inner wall 13c, and a right inner wall 13d. The front inner wall 13a protrudes rearward from the front outer wall 12a. The front inner wall 13a is not provided in a portion of the front outer wall 12a where the connector opening 121 is provided. The rear inner wall 13b protrudes forward from the rear outer wall 12b. The left inner wall 13c protrudes rightward from the left outer wall 12c. The right inner wall 13d protrudes leftward from the right outer wall 12d.

[0023] The left end of the front inner wall 13a and the front end of the left inner wall 13c are connected to form a first inner wall corner 131. The right end of the front inner wall 13a and the front end of the right inner wall 13d are connected to form a second inner wall corner 132. The left end of the rear inner wall 13b and the rear end of the left inner wall 13c are connected to form a third inner wall corner 133. The right end of the rear inner wall 13b and the rear end of the right inner wall 13d are connected to form a fourth inner wall corner 134.

[0024] The internal wall 13 further includes a first partition wall 13e and a second partition wall 13f. The first partition wall 13e and the second partition wall 13f divide the space within the housing 1 into multiple sections. The first partition wall 13e extends in the left-right direction. The first partition wall 13e connects a position between the front and rear ends of the left internal wall 13c and a position between the front and rear ends of the right internal wall 13d. The second partition wall 13f extends in the front-rear direction. The second partition wall 13f connects a position between the left and right ends of the front internal wall 13a and a position between the left and right ends of the first partition wall 13e.

[0025] Fig. 5 is a schematic cross-sectional view taken along line VV in Fig. 1. Fig. 6 is a schematic cross-sectional view taken along line VI-VI in Fig. 1. Fig. 7 is a schematic cross-sectional view taken along line VII-VII in Fig. 1. As shown in Figs. 5 to 7, the circuit board 2 is placed on the upper surface of the inner wall 13.

[0026] Specifically, the top surfaces of the front inner wall 13 a, the rear inner wall 13 b, the left inner wall 13 c, the right inner wall 13 d, the first partition wall 13 e, and the second partition wall 13 f are aligned at the same height in the vertical direction. The circuit board 2 is placed on the top surfaces of the front inner wall 13 a, the rear inner wall 13 b, the left inner wall 13 c, the right inner wall 13 d, the first partition wall 13 e, and the second partition wall 13 f.

[0027] Glands (not shown) are provided on the underside of the circuit board 2 at positions facing the upper surfaces of the front inner wall 13a, rear inner wall 13b, left inner wall 13c, right inner wall 13d, first partition wall 13e, and second partition wall 13f. As a result, the front inner wall 13a, rear inner wall 13b, left inner wall 13c, right inner wall 13d, first partition wall 13e, and second partition wall 13f come into metallic contact with the circuit board 2. In other words, the inner walls 13 and the circuit board 2 come into metallic contact with each other.

[0028] 3 to 7, in electronic device 100, electronic components 21 mounted on the lower surface of circuit board 2 are disposed in a space surrounded by inner walls 13. Specifically, electronic components 21 are disposed in a first space S1 surrounded by rear inner wall 13b, left inner wall 13c, right inner wall 13d, and first partition wall 13e.

[0029] The power connector 221 attached to the underside of the circuit board 2 is disposed in a second space S2 surrounded by the front inner wall 13a, the left inner wall 13c, the first partition wall 13e, and the second partition wall 13f. However, the power connector 221 is exposed to the outside through the connector opening 121 described above.

[0030] Although not shown in detail, the signal connector 222 attached to the underside of the circuit board 2 is disposed in a third space S3 surrounded by the front inner wall 13a, the right inner wall 13d, the first partition wall 13e, and the second partition wall 13f. However, the signal connector 222 is exposed to the outside through the connector opening 121 described above.

[0031] 5 to 7, the circuit board 2 is fixed to the housing 1 using fastening members 4 together with the cover 3, which is disposed on the second surface (upper surface) 2b side, which is the opposite side to the first surface (lower surface) 2a, which is the surface facing the internal wall 13. In detail, the circuit board 2 is covered from above by the metal cover 3, and is fastened together with the metal cover 3 to the housing 1 by the fastening members 4, which are metal screws. For this reason, the circuit board 2, which is disposed within the housing 1 and covered by the cover 3, is disposed in a space surrounded by metal.

[0032] As can be seen from the above description, in the electronic device 100 of this embodiment, the electronic components 21 mounted on the circuit board 2 are surrounded by the inner wall 13 of the metal housing 1. The inner wall 13 is configured to make metallic contact with a ground provided on the circuit board 2. Therefore, in the configuration of this embodiment, the ground can be strengthened by utilizing the metallic contact between the circuit board 2 and the housing 1. As a result, an electromagnetic noise blocking structure can be provided for the electronic components 21 mounted on the circuit board 2. In other words, in the electronic device 100 of this embodiment, it is possible to prevent the electronic components 21 from being affected by electromagnetic noise entering from the outside and to prevent electronic noise from being emitted from the electronic components 21 to the outside.

[0033] Furthermore, in this embodiment, there is a concern that electromagnetic noise generated from the connector 22 portion (particularly the power connector 221 portion) of the electronic device 100 may affect the electronic component 21. However, the interior wall 13 surrounding the electronic component 21 includes a partition wall (first partition wall) 13e that separates the connector 22 from the electronic component 21. In other words, the first space S1 in which the electronic component 21 is disposed is separated from the second space S2 and the third space S3 in which the connector 22 is disposed by the first partition wall 13e. With this configuration, it is possible to prevent electromagnetic noise generated in the connector 22 portion from affecting the electronic component 21.

[0034] [2-2. Details] As described above, the housing 1 is a die-cast molded product. For this reason, the housing 1 is manufactured through a process of forcing a metal (in this example, an aluminum alloy) molten at a high temperature into a mold, and a process of releasing the molded product from the mold after the molten metal has been forced into the mold and solidified. In the demolding process, the molded product (housing 1) is removed from the mold by pushing it out with an ejector pin (not shown). Assuming that the molded product, housing 1, is placed in the mold in the orientation shown in FIG. 4, the ejector pin pushes the housing 1 in the -Z direction (toward the back of the page). The ejector pin is, for example, cylindrical or other columnar, and typically, multiple ejector pins are used in the demolding process.

[0035] In the present embodiment, when the housing 1 has a thin, long partition wall (especially the first partition wall 13e) inside, the partition wall tends to be easily deformed during demolding. Taking this into consideration, in the demolding process, the molded product (housing 1) is removed by using some of the ejector pins that push out the molded product (housing 1) to push out the first partition wall 13e. This configuration can prevent deformation of the first partition wall 13e.

[0036] In this embodiment, among the multiple ejection pins, the ejection pins that push out parts other than the first partition wall 13e push out parts other than the inner wall 13. However, the ejection pins that push out parts other than the first partition wall 13e may also be used to push out other parts of the inner wall 13, such as the second partition wall 13f. In this embodiment, a plurality of ejection pins are used to push out the first partition wall 13e part.

[0037] Incidentally, when a push-out pin is used for pushing out the housing 1 during the demolding process, pin marks, which are marks left by the push-out pin, are usually left on the housing 1. Fig. 8 is a schematic cross-sectional view illustrating pin marks 14 formed on a partition wall 13eA shown as a comparative example to the first partition wall 13e of this embodiment. As shown in Fig. 8, the pin marks 14 often have a concave shape.

[0038] In this embodiment, as described above, metal contact is made between the inner wall 13 and the circuit board 2 to suppress the effects of electromagnetic noise on the electronic component 21. If concave pin marks 14 as shown in FIG. 8 are formed on the upper surface of the first partition wall 13e, there is a possibility that the metal contact between the first partition wall 13e and the circuit board 2 will be insufficient. As a result, electromagnetic noise generated, for example, in the power connector 221 area or the like may enter the first space S1 in which the electronic component 21 is disposed and affect the electronic component 21.

[0039] Taking these points into consideration, in this embodiment, as shown in Fig. 9, the housing 1 is configured to have a protrusion 15 provided on the surface (upper surface) of the internal wall 13 facing the circuit board 2, and making metallic contact with the circuit board 2. Fig. 9 is a cross-sectional view showing a schematic configuration of the protrusion 15 provided on the internal wall 13. More specifically, the protrusion 15 makes metallic contact with a ground provided on the circuit board 2. Furthermore, it is preferable that the protrusion 15 be configured to slightly protrude from the upper surface of the internal wall 13.

[0040] By providing the protrusions 15 on the upper surface of the inner wall 13 in this manner, the protrusions 15 can be used to facilitate metal contact between the inner wall 13 and the circuit board 2 placed on the inner wall 13 at a targeted position. Even with this configuration, there is a possibility of insufficient metal contact between the inner wall 13 and the circuit board, as with the case where the concave pin marks 14 are formed. However, it is difficult to ensure that a surface parallel to the main surface of the circuit board 2 over a wide area of ​​the upper surface of the inner wall 13 is inherently parallel. For this reason, providing the protrusions 15 as in this embodiment is preferable because it ensures a targeted position at which metal contact can be achieved. If metal contact can be achieved at a targeted position, it becomes easier to implement other measures to block electromagnetic noise, as described below. Furthermore, providing the protrusions 15 on the upper surface of the inner wall 13 can minimize the number of leaf springs and screws required to achieve metal contact between the housing 1 and the circuit board 2 at a targeted position. This minimizes the occurrence of dead space on the circuit board 2 due to the placement of the leaf springs and screws.

[0041] Circle 16, shown by a dashed line in FIG. 4, indicates the position where an ejector pin abuts on inner wall 13. As can be seen from FIG. 4, protrusion 15 is provided at a position where an ejector pin, used to eject housing 1 from the mold, abuts on housing 1. This configuration can prevent pin marks 14, which are recessed into the upper surface of inner wall 13 as described above, from being formed on inner wall 13. In this configuration, tolerance control is performed on the amount of protrusion of protrusion 15 from the upper surface of inner wall 13 after ejection by the ejector pin. Such tolerance control may be, for example, a configuration in which the amount of protrusion is controlled to be equal to or greater than 0 mm and equal to or less than 0.2 mm.

[0042] In this embodiment, the protrusion 15 is provided on the first partition wall 13e that separates the connector 22 from the electronic component 21. With this configuration, an electromagnetic noise blocking structure can be appropriately provided for the portion of the inner wall 13 that will be pushed out by the ejector pin when the housing 1 is removed from the mold. Also, with this configuration, an electromagnetic noise blocking structure can be appropriately provided for the portion where electromagnetic noise is likely to occur due to the presence of the power connector 221, etc.

[0043] The protrusion 15 may be provided in a location other than the first partition wall 13e of the inner wall 13. The protrusion 15 is not limited to a portion of the inner wall 13 where the ejector pin is to be placed, and may be provided in a position where the ejector pin is not to be placed.

[0044] 4, in this embodiment, a plurality of protrusions 15 are provided at intervals on the inner wall 13 (specifically, the first partition wall 13e). This makes it possible to appropriately provide an electromagnetic noise blocking structure even for a wall such as the first partition wall 13e, which has a long wall portion and multiple extrusion points due to extrusion pins.

[0045] When multiple protrusions 15 are provided at intervals on the inner wall 13 as in this embodiment, it is preferable that the interval between adjacent protrusions 15 corresponds to the pitch at which electromagnetic noise is blocked at at least one location. The pitch at which electromagnetic noise is blocked is determined by the wavelength of the electromagnetic noise to be blocked. The electromagnetic noise to be blocked is determined appropriately depending on, for example, the design of the electronic device 100.

[0046] The following effect can be obtained by configuring the positions of the protrusions 15 to be aligned with the pitch required to block electromagnetic noise: Even if a gap is created between the circuit board 2 and the internal wall 13 (in the vertical direction) due to the presence of the protrusions 15 when the circuit board 2 and the internal wall 13 are in metal contact with each other, it is possible to prevent electromagnetic noise from entering the space where the electronic component 21 is placed (first space S1 in this embodiment).

[0047] Furthermore, the housing 1 is preferably configured to have a fixing portion 17 between at least one adjacent protrusion 15, which fixes the circuit board 2 to the internal wall 13 using a fastening member 4. In this embodiment, the fastening member 4 is a screw, as described above. For this reason, the fixing portion 17 in this embodiment is provided with a screw hole 171. In other words, the fixing portion 17 is a screw-fastening portion.

[0048] By providing fixing portions 17 in this manner, it is possible to increase the number of locations where metal contact can be made between inner wall 13 and circuit board 2 at targeted positions, in addition to protrusions 15. Furthermore, it is possible to prevent circuit board 2 from floating relative to inner wall 13 between protrusions 15.

[0049] In this embodiment, a plurality of locations where the fastening members 4 are used to fasten the circuit board 2 and the inner wall 13 in a metallic contact state are provided in addition to between adjacent protrusions 15. For example, such fastening locations include locations corresponding to the four corners of the circuit board 2. The locations corresponding to the four corners of the circuit board 2 correspond to the first inner wall corner 131, the second inner wall corner 132, the third inner wall corner 133, and the fourth inner wall corner 134 (see FIG. 4 ). By providing a plurality of fastening locations using the fastening members 4, even if the circuit board 2 is bent, the circuit board 2 and the inner wall 13 can be brought into metallic contact at the desired locations. Because metallic contact is easily achieved at the locations where the protrusions 15 are provided and fastening with the fastening members 4 is not required, this embodiment avoids providing too many locations for the fastening portions 17.

[0050] In this embodiment, as shown in Fig. 4 and other figures, the fixing portion 17 is provided at the location where the first partition wall 13e and the second partition wall 13f connect (intersect). By providing the fixing portion 17 at such a location, it is possible to ensure a state in which the internal wall 13 and the circuit board 2 are in firm metal contact between the two spaces S2 and S3 in which the connectors 22 are arranged. For example, it is possible to prevent electromagnetic noise generated from the power connector 221 from entering the space S3 in which the signal connector 222 is arranged. Furthermore, by providing the fixing portion 17 at the location where these two walls connect, it is possible to provide the fixing portion 17 in a location with high rigidity.

[0051] <4. Things to keep in mind> Various technical features disclosed in the description of the present invention may be modified in various ways without departing from the spirit of the technical creation. Furthermore, multiple embodiments and modifications disclosed in the description of the present invention may be combined to the extent possible. [Explanation of symbols]

[0052] 1. Housing 2. Circuit board 2a...1st page 2b...2nd side 3. Cover 4. Fastening member 13...Internal wall 13e First partition wall (partition wall) 15. Convex part 17... Fixed part 21. Electronic Components 22···Connector 100...electronic equipment 221···Power Connector

Claims

1. a circuit board on which electronic components are mounted; a metal housing in which the circuit board is disposed; Equipped with The housing includes: an inner wall on which the circuit board is placed and which surrounds the electronic components; a protrusion provided on a surface of the inner wall facing the circuit board and in metallic contact with the circuit board; An electronic device comprising:

2. the housing is a molded part, The electronic device according to claim 1 , wherein the protrusion is provided at a position where an ejector pin used to eject the housing from a mold is placed.

3. The electronic device according to claim 2 , wherein a plurality of the protrusions are provided on the inner wall at intervals.

4. 4. The electronic device according to claim 3, wherein the interval between adjacent convex portions corresponds to a pitch that blocks electromagnetic noise at at least one location.

5. The electronic device according to claim 3 , wherein the housing has a fixing portion between at least one adjacent pair of the protrusions for fixing the circuit board to the inner wall using a fastening member.

6. 6. The electronic device according to claim 5, wherein the circuit board is fixed to the housing using the fastening member together with a cover arranged on a second surface side opposite to a first surface side facing the internal wall.

7. a connector attached to the circuit board; the internal wall includes a partition wall that separates the connector and the electronic component, The electronic device according to claim 1 , wherein the protrusion is provided on the partition wall.

8. The electronic device according to claim 7 , wherein the connector includes a power connector that is connected to a power line that supplies power from a power source.

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