Electronic substrate unit

Abstract

To secure easiness in assembling while suppressing the area where a component can be mounted on a substrate from becoming small.SOLUTION: An electronic substrate unit comprises: a substrate 20 on which a plurality of mounted components 21 including electronic components 22 are mounted; an upper cover 31 which covers a surface of the substrate 20 on a side where the mounted components 21 are mounted; a lower cover 41 which covers the surface of the substrate 20 on an opposite side to the surface that the upper cover 31 covers; a second guide rail 61 which is arranged at one of the upper cover 31 and lower cover 41, and extends toward a side where the other one of the upper cover 31 and lower cover 41 is positioned, to engage the other one, with length of the second guide rail in the extending direction being longer than that of a first guide rail 51; and the first guide rail 51 which extends toward a side where the other one of the upper cover 31 or the lower cover 41 is positioned, to engage the other one.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an electronic board unit. [Background technology]

[0002] An electronic board unit mounted on a vehicle has a board on which electronic components are mounted and a cover that covers the board, and is configured by combining these. In addition, in assembling such a conventional electronic board unit, a jig provided with a pilot pin for aligning the board and the cover is used, and the assembly is performed while aligning the board and the cover. For example, in Patent Document 1, the wiring board assembly and the main cover are assembled while positioning is performed by inserting a guide pin erected on an assembly table into a positioning hole formed in the main cover and the wiring board assembly. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2005-65421 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, when forming a hole for a pilot pin in the board, it is necessary to reduce the area on the board where electronic components can be mounted. In this case, the number of components that can be mounted on one board is reduced. For this reason, it is difficult to simultaneously prevent the area on the board where components can be mounted from becoming smaller and ensure ease of assembly of the board and the cover.

[0005] The present invention has been made in consideration of the above, and aims to provide an electronic board unit that can ensure ease of assembly while preventing a reduction in the area on the board on which components can be mounted. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems and achieve the object, the electronic board unit of the present invention is characterized in comprising a board on which a plurality of mounted components including electronic components are mounted, an upper cover covering the surface of the board on which the mounted components are mounted, a lower cover covering the surface of the board opposite to the surface covered by the upper cover, a first guide rail arranged on one of the upper cover and the lower cover, extending to a side where the other of the upper cover and the lower cover are located and engaging with the other, and a second guide rail arranged on one of the upper cover and the lower cover, extending to a side where the other of the upper cover and the lower cover are located and engaging with the other, the second guide rail having a length in the extension direction longer than that of the first guide rail. Effect of the Invention

[0007] In the electronic board unit according to the present invention, the board is covered with an upper cover and a lower cover, and the lower cover is provided with a first guide rail and a second guide rail that engage with the upper cover. This allows the upper cover and the lower cover to be assembled while the first guide rail and the second guide rail guide the upper cover without providing a pilot pin used for positioning when assembling the electronic board unit on the upper cover and the lower cover. In addition, since there is no need to provide a pilot pin on the upper cover or the lower cover, there is no need to form a hole for the pilot pin on the board, and the area on the board where components can be mounted can be prevented from becoming small. In addition, the first guide rail and the second guide rail that are arranged on the lower cover and engage with the upper cover are higher in height than the first guide rail. Therefore, when the board is arranged between the upper cover and the lower cover and the first guide rail and the second guide rail are engaged with the upper cover, the first guide rail and the second guide rail can be engaged with the upper cover in order. That is, when assembling the upper cover to the lower cover, it is possible to assemble it from a position closer to the first guide rail, which is lower, and then assemble it at a position closer to the second guide rail, which is higher. This allows the upper cover to be gradually moved closer to the lower cover while aligning the upper cover with the board at a position closer to the first guide rail and then assembled to the lower cover. Therefore, even when high accuracy in assembling the board and the upper cover at a position closer to the first guide rail is required, the upper cover and the lower cover can be easily assembled to cover the board while ensuring the assembly accuracy. As a result, it is possible to ensure ease of assembly while preventing the area on the board where components can be mounted from becoming smaller. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view of an electronic board unit according to an embodiment. [Diagram 2] FIG. 2 is an exploded perspective view of the electronic board unit shown in FIG. [Diagram 3]FIG. 3 is an exploded perspective view of the electronic board unit shown in FIG. 1 as viewed from the side where the first guide rail is arranged. [Figure 4] FIG. 4 is a detailed view of part A in FIG. 2, showing the second guide rail. [Diagram 5] FIG. 5 is a detailed view of part B in FIG. 3, showing the first guide rail. [Figure 6] 6 is a view of the lower cover shown in FIG. 2 taken along the line CC. [Figure 7] FIG. 7 is an explanatory diagram for explaining the assembly of the board and the cover. [Figure 8] FIG. 8 is a perspective view showing the lower cover and the upper cover in an engaged state, as seen from the side where the first guide rail is located. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to this embodiment. In addition, the components in the following embodiments include those that are replaceable and easy for a person skilled in the art, or those that are substantially the same.

[0010] [Embodiment] FIG. 1 is a perspective view of an electronic board unit 10 according to an embodiment. FIG. 2 is an exploded perspective view of the electronic board unit 10 shown in FIG. 1. FIG. 3 is an exploded perspective view of the electronic board unit 10 shown in FIG. 1, seen from the side where the first guide rail 51 is arranged. The electronic board unit 10 according to the embodiment has a board 20 on which a plurality of mounting components 21 are mounted, and a cover 30 that covers the board 20, and is configured by covering both sides of the board 20 with the cover 30. The mounting components 21 mounted on the board 20 include electronic components 22, pin headers 23 that are terminals for exchanging signals with an external device (not shown), and a horizontal connector 24 to which a connector (not shown) that supplies power to the electronic board unit 10 is connected. In this embodiment, a plurality of electronic components 22, pin headers 23, and horizontal connectors 24 are each mounted on one side of the board 20.

[0011] The pin header 23 has a plurality of pins, and is arranged on the substrate 20 with the direction in which the pins extend being the thickness direction of the substrate 20. The horizontal connector 24 is arranged so that the direction in which an external connector is attached to and detached from the horizontal connector 24 is along the plane of the substrate 20.

[0012] The substrate 20 has a substantially rectangular shape when viewed in the thickness direction of the substrate 20, and the horizontal connector 24 is disposed at one side of the rectangle of the substrate 20. The two horizontal connectors 24 are disposed side by side in the extension direction of the side of the substrate 20 on which the horizontal connectors 24 are disposed.

[0013] The multiple pin headers 23 arranged on the board 20 are mostly arranged near the side opposite the side on which the horizontal connector 24 is arranged, in the rectangular shape of the board 20. That is, the board 20 has an area where many pin headers 23 are arranged near the side opposite the side on which the horizontal connector 24 is arranged, and the multiple pin headers 23 mounted on the board 20 are mainly arranged in this area.

[0014] The electronic components 22 mounted on the substrate 20 are mainly disposed in positions between the side of the rectangular substrate 20 on which the horizontal connectors 24 are disposed and the side on which many of the pin headers 23 are disposed. In other words, in the substrate 20 formed in a substantially rectangular shape, if the direction in which the two horizontal connectors 24 are lined up is the horizontal direction of the rectangle and the direction perpendicular to the horizontal direction is the vertical direction of the rectangle, the electronic components 22 are mainly disposed in the vertical direction between the position where the horizontal connectors 24 are disposed and the area where many of the pin headers 23 are disposed.

[0015] In other words, with respect to the region where the pin headers 23 are arranged, when the board 20 is divided into two regions with the middle position in the vertical direction of the board 20 as the boundary, more pin headers 23 are arranged in the region on the side where the horizontal connector 24 is not arranged than in the region on the side where the horizontal connector 24 is arranged. For this reason, in this embodiment, when the board 20 is divided into two regions in the vertical direction, the region on the side where the horizontal connector 24 is not arranged is the region on the side where more pin headers 23 are arranged.

[0016] In the description of this embodiment, the horizontal direction of the rectangle in the substrate 20 is also referred to as the horizontal direction in the cover 30, and the vertical direction of the rectangle in the substrate 20 is also referred to as the vertical direction in the cover 30.

[0017] The cover 30 has an upper cover 31 that covers the surface of the board 20 on which the mounted components 21 are mounted, and a lower cover 41 that covers the surface of the board 20 opposite to the surface covered by the upper cover 31. The upper cover 31 and the lower cover 41 are formed to have a substantially rectangular shape when viewed in the direction covering the board 20. In other words, the upper cover 31 and the lower cover 41 are shaped to fit the board 20 so as to be able to cover the board 20, but the board 20 is shaped to be substantially rectangular when viewed in the thickness direction. For this reason, the upper cover 31 and the lower cover 41 that are formed to fit the board 20 are also formed to have a substantially rectangular shape when viewed in the direction covering the board 20, i.e., in the thickness direction of the board 20, similar to the board 20.

[0018] The upper cover 31 has an upper surface portion 32 formed in a substantially rectangular shape with the substrate 20 and disposed in a direction along the substrate 20, and side walls 33 erected on the outer periphery of the upper surface portion 32 and extending toward the side where the lower cover 41 is located. That is, the side walls 33 of the upper cover 31 are formed on each of the four sides of the upper surface portion 32 formed in a substantially rectangular shape. The upper surface portion 32 may have projections and recesses according to the mounting components 21 mounted on the substrate 20. In this embodiment, the upper surface portion 32 is formed so that a position corresponding to the position of the electronic component 22 mounted on the substrate 20 protrudes toward the opposite side to the side where the lower cover 41 is located.

[0019] The lower cover 41 has a lower surface portion 42 that is formed in a substantially rectangular shape together with the substrate 20 and is oriented along the substrate 20, and side walls 43 that are erected on the outer periphery of the lower surface portion 42 and extend toward the side where the upper cover 31 is located. In other words, the side walls 43 of the lower cover 41 are formed on each of the four sides of the lower surface portion 42 that is formed in a substantially rectangular shape.

[0020] The lower cover 41 covers the substrate 20 from the side opposite to the side where the upper cover 31 is located, and the size of the portion surrounded by the side wall 43 is larger than the size of the substrate 20. Therefore, the lower cover 41 allows the substrate 20 to be placed on the lower surface portion 42 by inserting the substrate 20 inside the side wall 43.

[0021] The upper cover 31, which covers the substrate 20 from the side opposite to the side of the substrate 20 where the lower cover 41 is located, has a portion surrounded by a side wall 33 that is larger than the size of the substrate 20. Therefore, the upper cover 31 is capable of covering the substrate 20 by inserting the substrate 20 inside the side wall 33. Furthermore, the size of the portion surrounded by the side wall 33 of the upper cover 31, i.e., the size of the inner peripheral surface of the side wall 33 of the upper cover 31, is larger than the size of the outer peripheral surface of the side wall 43 of the lower cover 41.

[0022] Therefore, when covering the substrate 20 from both sides with the upper cover 31 and the lower cover 41, the side wall 43 of the lower cover 41, on whose underside portion 42 the substrate 20 is placed, is inserted inside the side wall 33 of the upper cover 31. As a result, the substrate 20 is positioned in the internal space between the upper cover 31 and the lower cover 41.

[0023] In this manner, an opening 37 is formed in the side wall 33 of the upper cover 31 covering the board 20 at a position corresponding to the horizontal connector 24 mounted on the board 20, for exposing the horizontal connector 24 to the outside of the cover 30. The opening 37 formed in the side wall 33 is formed as a notch relative to the side wall 33. Similarly, an opening 47 is formed in the side wall 43 of the lower cover 41 covering the board 20 at a position corresponding to the horizontal connector 24 mounted on the board 20, for exposing the horizontal connector 24 to the outside of the cover 30. The opening 47 formed in the side wall 43 is formed as a notch relative to the side wall 43.

[0024] The horizontal connector 24 mounted on the board 20 is disposed at the position of the opening 37 of the upper cover 31 and the opening 47 of the lower cover 41 when the board 20 is covered with the upper cover 31 and the lower cover 41. Therefore, when the board 20 is covered with the cover 30, the horizontal connector 24 is exposed from the space inside the cover 30 to the outside of the cover 30, making it possible to connect an external connector.

[0025] Furthermore, the upper cover 31 has a terminal hole 36 into which the pin header 23 is inserted, at a position corresponding to the pin header 23 mounted on the board 20. The terminal hole 36 is a hole that penetrates the top surface portion 32 of the upper cover 31 in the thickness direction of the board 20. The terminal hole 36 is formed in a position on the top surface portion 32 of the upper cover 31 that corresponds to the pin header 23 when the board 20 is covered with the upper cover 31.

[0026] Many of the pin headers 23 mounted on the board 20 are disposed near the side opposite the side on which the horizontal connector 24 is disposed, of the board 20 which is formed in a substantially rectangular shape. Therefore, many of the terminal holes 36 formed in the upper cover 31 are disposed near the side opposite the side on which the side wall 33 on which the opening 37 is formed is located, of the upper surface portion 32 of the upper cover 31 which is formed in a substantially rectangular shape.

[0027] When the board 20 is covered with the cover 30, the pins of the pin header 23 mounted on the board 20 fit into the terminal holes 36, so that the pins of the pin header 23 are exposed from the space inside the cover 30 to the outside of the cover 30. This makes it possible to connect an external connector to the multiple pins of the pin header 23 when the board 20 is covered with the cover 30.

[0028] The cover 30 covering the substrate 20 as described above has a first guide rail 51 and a second guide rail 61 used for assembling the upper cover 31 and the lower cover 41. The first guide rail 51 is disposed on one of the covers 30, the upper cover 31 and the lower cover 41, and extends to the side where the other cover 30 is located to engage with the other cover 30. The second guide rail 61 is disposed on the cover 30, the upper cover 31 and the lower cover 41, on which the first guide rail 51 is disposed, and extends to the side where the other cover 30 is located to engage with the other cover 30, and has a length in the extending direction longer than the first guide rail 51.

[0029] In this embodiment, the first guide rail 51 and the second guide rail 61 are both disposed in the lower cover 41, and extend from the lower cover 41 to the side where the upper cover 31 is located to engage with the upper cover 31. In detail, the first guide rail 51 and the second guide rail 61 are disposed at the corners of the lower cover 41, which is formed in a substantially rectangular shape when the lower cover 41 is viewed in the thickness direction of the substrate 20, and extend to the side where the upper cover 31 is located. Furthermore, the first guide rail 51 and the second guide rail 61 are disposed at diagonal positions of the rectangle in the lower cover 41, which is formed in a substantially rectangular shape.

[0030] Among these, the second guide rail 61 is disposed at a corner located at the end of the side of the lower cover 41 where the side wall 43 where the opening 47 is formed is disposed. The first guide rail 51 is disposed at the end of the side of the lower cover 41 opposite to the side where the side wall 43 where the opening 47 is formed is disposed, and is disposed at a corner diagonally opposite to the corner where the second guide rail 61 is disposed. In other words, the first guide rail 51 is disposed at a corner located at the end of the side of the lower cover 41 that extends laterally and is located near the area where many pin headers 23 are disposed when the board 20 is disposed on the lower surface portion 42 of the lower cover 41. Therefore, when the board 20 is disposed on the lower surface portion 42 of the lower cover 41, more pin headers 23 are mounted on the board 20 at a position closer to the first guide rail 51 than at a position closer to the second guide rail 61.

[0031] 2, and is a detailed view of the second guide rail 61. The second guide rail 61 has a vertical guide portion 62 extending along one side of the rectangular shape of the lower cover 41, and a horizontal guide portion 63 extending along a side perpendicular to the side along which the vertical guide portion 62 extends.

[0032] In detail, the lateral guide portion 63 is a plate-like member extending from an end portion of the side wall 43 opposite to the side where the lower surface portion 42 is located toward the opposite side to the side where the lower surface portion 42 is located, in a width direction along the side wall 43 in the lower cover 41 that is perpendicular to the side wall 43 in which the opening 47 is formed, in a width direction along the side wall 43 in the lower cover 41 that is perpendicular to the side wall 43 in which the opening 47 is formed, in a width direction, and is a plate-like member extending from an end portion of the side wall 43 opposite to the side where the lower surface portion 42 is located toward the opposite side to the side where the lower surface portion 42 is located.

[0033] The lateral guide portion 63 and the vertical guide portion 62 of the second guide rail 61 each formed in a plate shape are connected to each other at their ends closer to the other side. As a result, the second guide rail 61 is formed in an L-shape when the second guide rail 61 is viewed in the thickness direction of the substrate 20 placed on the lower surface portion 42 of the lower cover 41. When the substrate 20 is covered with the upper cover 31 and the lower cover 41, the second guide rail 61 formed in this manner fits inside the side wall 33 of the upper cover 31, similar to the side wall 43 of the lower cover 41.

[0034] In addition, the second guide rail 61 has an engagement protrusion 64 that engages with the upper cover 31. The engagement protrusion 64 is formed in a lateral guide portion 63 of the second guide rail 61. The engagement protrusion 64 is formed on a surface of the lateral guide portion 63 of the second guide rail 61 that is located on the same side as the outer circumferential surface of the side wall 43 of the lower cover 41, and is formed to protrude from the surface of the lateral guide portion 63.

[0035] The upper cover 31 is formed with a second engagement hole 35 (see FIG. 2) with which the engagement protrusion 64 engages when the second guide rail 61 enters inside the side wall 33 of the upper cover 31. The second engagement hole 35 is formed in the side wall 33 that overlaps the lateral guide portion 63 of the second guide rail 61 outside the lateral guide portion 63 when the second guide rail 61 enters inside the side wall 33 of the upper cover 31, and is a hole that penetrates the side wall 33. When the second guide rail 61 enters inside the side wall 33 of the upper cover 31, the engagement protrusion 64 formed in the second guide rail 61 enters the second engagement hole 35 formed in the side wall 33 of the upper cover 31 (see FIG. 1), thereby engaging with the second engagement hole 35 and engaging with the upper cover 31.

[0036] 3, and is a detailed view of the first guide rail 51. The first guide rail 51 has a vertical guide portion 52 extending along one side of the rectangular shape of the lower cover 41, and a horizontal guide portion 53 extending along a side perpendicular to the side along which the vertical guide portion 52 extends.

[0037] The lateral guide portion 53 is a plate-like member extending from an end portion of the side wall 43 opposite to the side wall 43 in which the opening 47 is formed in the lower cover 41, toward the opposite side to the side where the lower surface portion 42 is located, on the side wall 43. The vertical guide portion 52 is a plate-like member extending from an end portion of the side wall 43 perpendicular to the side wall 43 in which the lateral guide portion 53 of the first guide rail 51 is arranged, toward the opposite side to the side where the lower surface portion 42 is located, on the side wall 43, on the lower cover 41.

[0038] The horizontal guide portion 53 and the vertical guide portion 52 of the first guide rail 51 each formed in a plate shape are connected to each other at their ends closer to the other. As a result, the first guide rail 51 is formed in an L-shape when the first guide rail 51 is viewed in the thickness direction of the substrate 20 placed on the lower surface portion 42 of the lower cover 41. When the substrate 20 is covered with the upper cover 31 and the lower cover 41, the first guide rail 51 formed in this manner fits inside the side wall 33 of the upper cover 31, similar to the side wall 43 of the lower cover 41.

[0039] Furthermore, the first guide rail 51 has an engaging protrusion 54 that engages with the upper cover 31. The engaging protrusion 54 is formed in a lateral guide portion 53 of the first guide rail 51. The engaging protrusion 54 is formed on a surface of the lateral guide portion 53 of the first guide rail 51 that is located on the same side as the outer circumferential surface of the side wall 43 of the lower cover 41, and is formed to protrude from the surface of the lateral guide portion 53.

[0040] The upper cover 31 is formed with a first engagement hole 34 (see FIG. 3) with which the engagement protrusion 54 engages when the first guide rail 51 enters inside the side wall 33 of the upper cover 31. The first engagement hole 34 is formed in the side wall 33 that overlaps the lateral guide portion 53 of the first guide rail 51 outside the lateral guide portion 53 when the first guide rail 51 enters inside the side wall 33 of the upper cover 31, and is a hole that penetrates the side wall 33. When the first guide rail 51 enters inside the side wall 33 of the upper cover 31, the engagement protrusion 54 formed in the first guide rail 51 enters the first engagement hole 34 formed in the side wall 33 of the upper cover 31 (see FIG. 8), thereby engaging with the first engagement hole 34 and engaging with the upper cover 31.

[0041] Fig. 6 is a view of the lower cover 41 as seen from the arrow CC in Fig. 2. The first guide rail 51 and the second guide rail 61 formed on the lower cover 41 are longer than the first guide rail 51 in the length in the extension direction toward the side where the upper cover 31 is located with respect to the lower cover 41 when the cover 30 covers the board 20. In other words, the first guide rail 51 and the second guide rail 61 are such that the height H2 of the second guide rail 61 in the thickness direction of the board 20 is greater than the height H1 of the first guide rail 51.

[0042] Next, the assembly of the board 20 and the cover 30 in the electronic board unit 10 according to the embodiment will be described. FIG. 7 is an explanatory diagram for explaining the assembly of the board 20 and the cover 30. When assembling the board 20 and the cover 30, the board 20 is first placed on the lower surface portion 42 of the lower cover 41. The board 20 is inserted inside the side wall 43 of the lower cover 41 and placed on the surface of the lower surface portion 42 of the lower cover 41 on the side where the side wall 43 is formed. At that time, the board 20 is placed in such a direction that the surface opposite to the surface on which the mounted components 21 are placed faces the lower surface portion 42 of the lower cover 41, and the surface on which the mounted components 21 are placed faces the opposite side to the side on which the lower surface portion 42 is located. In addition, the board 20 is placed in such a direction that the horizontal connector 24 mounted on the board 20 is placed at the position of the opening 47 formed in the side wall 43 of the lower cover 41, and the area in which many pin headers 23 are placed is placed near the first guide rail 51.

[0043] The upper cover 31 covers the board 20 thus arranged on the lower cover 41 from the surface on which the mounted components 21 are mounted, and is assembled by engaging with the lower cover 41. When assembling the upper cover 31 to the lower cover 41, the upper cover 31 is assembled with the surface of the upper surface portion 32 on which the side wall 33 is arranged facing the side on which the lower cover 41 is located. The upper cover 31 is also assembled with the side wall 33 on which the opening 37 is formed positioned on the side on which the horizontal connector 24 of the board 20 arranged on the lower cover 41 is positioned, and the side on which many terminal holes 36 are formed positioned on the side on which the area on the board 20 on which many pin headers 23 are positioned is positioned.

[0044] At that time, the upper cover 31 is moved closer to the lower cover 41 while being inclined with respect to the lower cover 41 in a direction in which the side where the sidewall 33 where the first engagement hole 34 is formed is closer to the lower cover 41 than the side where the sidewall 33 where the second engagement hole 35 is formed is located. In other words, the upper cover 31 is moved closer to the lower cover 41 while being inclined with respect to the lower cover 41 in a direction in which the side where more terminal holes 36 are formed is closer to the lower cover 41 than the side where the sidewall 33 where the opening 37 is located is located. As a result, first, the first guide rail 51 formed in the lower cover 41 is inserted inside the sidewall 33 formed in the upper cover 31.

[0045] Since many pin headers 23 to be mounted on the board 20 are arranged near the first guide rail 51 on the lower cover 41, the pins of the pin headers 23 are inserted into the terminal holes 36 formed on the upper surface portion 32 of the upper cover 31 while the upper cover 31 is guided by the first guide rail 51. After the pins of the pin headers 23 located more toward the first guide rail 51 are inserted into the terminal holes 36 formed on the upper surface portion 32 of the upper cover 31, the second guide rail 61 formed on the lower cover 41 is inserted into the inside of the side wall 33 formed on the upper cover 31.

[0046] 8 is a perspective view showing the state in which the lower cover 41 and the upper cover 31 are engaged, as viewed from the side where the first guide rail 51 is located. When the pins of the pin header 23 located more toward the first guide rail 51 enter the terminal holes 36 formed in the upper surface portion 32 of the upper cover 31 and the first guide rail 51 and the second guide rail 61 enter inside the side wall 33 of the upper cover 31, the upper cover 31 is moved further toward the lower cover 41. That is, the upper cover 31 is guided by the first guide rail 51 and the second guide rail 61 while being moved toward the lower cover 41.

[0047] As a result, the engaging protrusion 54 formed on the first guide rail 51 enters into the first engaging hole 34 of the upper cover 31 and engages with the first engaging hole 34, and the engaging protrusion 64 formed on the second guide rail 61 enters into the second engaging hole 35 of the upper cover 31 and engages with the second engaging hole 35 (see FIG. 1). In this way, the cover 30 places the board 20 inside the upper cover 31 and the lower cover 41, and by engaging the first guide rail 51 and second guide rail 61 of the lower cover 41 with the upper cover 31, the upper cover 31 and the lower cover 41 cover the board 20.

[0048] In the electronic board unit 10, even when the board 20 is covered with the cover 30, the pins of the pin header 23 are located inside the terminal holes 36 formed in the upper cover 31, so that an external connector can be connected to the pins of the pin header 23 through the terminal holes 36. In addition, the horizontal connector 24 is exposed to the outside of the cover 30 through an opening 37 formed in the side wall 33 of the upper cover 31 and an opening 47 formed in the side wall 43 of the lower cover 41, so that an external connector can be connected to the horizontal connector 24 from the outside of the cover 30.

[0049] In the electronic board unit 10 according to the above embodiment, the board 20 is covered with the upper cover 31 and the lower cover 41, and the lower cover 41 is provided with a first guide rail 51 and a second guide rail 61 that engage with the upper cover 31. This makes it possible to assemble the upper cover 31 and the lower cover 41 while guiding the upper cover 31 with the first guide rail 51 and the second guide rail 61, without providing the cover 30 with a pilot pin used for alignment when assembling the electronic board unit 10. In addition, since it is not necessary to provide the cover 30 with a pilot pin, it is also not necessary to form a hole for the pilot pin in the board 20, and it is possible to prevent the area on the board 20 where the mounting components 21 can be mounted from being reduced.

[0050] In addition, the first guide rail 51 and the second guide rail 61 are disposed in the lower cover 41 and engaged with the upper cover 31, and the height H2 of the second guide rail 61 is higher than the height H1 of the first guide rail 51. Therefore, when the board 20 is disposed between the upper cover 31 and the lower cover 41 and the first guide rail 51 and the second guide rail 61 are engaged with the upper cover 31, the first guide rail 51 and the second guide rail 61 can be engaged with the upper cover 31 in order. That is, when the upper cover 31 is assembled to the lower cover 41, the assembly can be started from a position close to the first guide rail 51 where the height H1 is low, and then the assembly can be started from a position close to the second guide rail 61 where the height H2 is high.

[0051] As a result, while aligning the upper cover 31 with respect to the board 20 at a position closer to the first guide rail 51, the upper cover 31 can be gradually brought closer to the lower cover 41 and assembled to the lower cover 41. Therefore, even when precision in assembling the board 20 and the cover 30 at a position closer to the first guide rail 51 is particularly required, the upper cover 31 and the lower cover 41 can be easily assembled to cover the board 20 while ensuring the assembly precision. As a result, ease of assembly can be ensured while preventing the area on the board 20 where the mounted components 21 can be mounted from becoming smaller.

[0052] Furthermore, more pin headers 23 are mounted on the board 20 closer to the first guide rail 51 than closer to the second guide rail 61, and the upper cover 31 is formed with terminal holes 36 into which the pin headers 23 fit at positions corresponding to the pin headers 23. Therefore, when assembling the upper cover 31, the upper cover 31 can be aligned with the board 20 at a position closer to the first guide rail 51 where the height H1 is lower, and many pin headers 23 positioned closer to the first guide rail 51 can be easily inserted into the terminal holes 36 of the upper cover 31. Therefore, the pin headers 23 mounted on the board 20 and the terminal holes 36 formed in the upper surface portion 32 of the upper cover 31 can be easily assembled, which requires high assembly accuracy. As a result, ease of assembly can be ensured.

[0053] Furthermore, the first guide rail 51 and the second guide rail 61 are disposed at diagonal positions of a rectangle, which is the shape of the upper cover 31 and the lower cover 41 when viewed in the direction covering the board 20, so that the upper cover 31 and the lower cover 41 can be easily assembled. In other words, since the first guide rail 51 and the second guide rail 61 are disposed at diagonal positions, the upper cover 31 and the lower cover 41 can be assembled while aligning the four sides of the rectangle of the upper cover 31 and the lower cover 41 with the first guide rail 51 and the second guide rail 61. As a result, ease of assembly can be ensured.

[0054] In addition, since the first guide rail 51 and the second guide rail 61 are disposed at two diagonal corners of a rectangle, it is possible to ensure ease of assembly of the upper cover 31 and the lower cover 41, and therefore the number of guide rails can be reduced compared to a case where guide rails are disposed at all corners of a rectangle. This makes it possible to reduce the amount of resin used as the material for the cover 30. As a result, the manufacturing cost can be reduced.

[0055] Furthermore, since the first guide rail 51 and the second guide rail 61 have the vertical guide portions 52, 62 and the horizontal guide portions 53, 63, respectively, the upper cover 31 and the lower cover 41 can be easily assembled together. In other words, since the first guide rail 51 and the second guide rail 61 have the vertical guide portions 52, 62 and the horizontal guide portions 53, 63, the upper cover 31 and the lower cover 41 can be assembled together while the relative positions of the upper cover 31 and the lower cover 41 in the vertical and horizontal directions are regulated by the first guide rail 51 and the second guide rail 61. As a result, ease of assembly can be ensured.

[0056] [Variations] In the above embodiment, the first guide rail 51 and the second guide rail 61 are disposed in the lower cover 41, but the first guide rail 51 and the second guide rail 61 may be disposed in the upper cover 31. In other words, the first guide rail 51 and the second guide rail 61 may be disposed in the upper cover 31, and the first engagement hole 34 with which the engagement protrusion 54 formed in the first guide rail 51 engages, and the second engagement hole 35 with which the engagement protrusion 64 formed in the second guide rail 61 engages may be formed in the lower cover 41.

[0057] In the above-described embodiment, the first guide rail 51 and the second guide rail 61 are used as guide rails for guiding the assembly of the upper cover 31 and the lower cover 41, but the number of guide rails may be more than two. For example, the guide rails may be disposed at all four corners of a rectangle that is the shape when the upper cover 31 and the lower cover 41 are viewed in the direction covering the board 20. When the guide rails are disposed at the four corners, for example, the two guide rails disposed at the corners at both ends of a side located near an area where many pin headers 23 are disposed may be the first guide rails 51, and the two guide rails disposed at the corners at both ends of a side opposite to this side may be the second guide rails 61.

[0058] In the above embodiment, the pin header 23 and the terminal hole 36 are given as an example of components that are to be assembled with high precision between the board 20 and the cover 30, but the components that are to be assembled with high precision may be other components. The first guide rail 51, which is lower in height relative to the second guide rail 61, is preferably disposed near components that require high assembly precision between the board 20 and the cover 30.

[0059] Furthermore, the electronic board units according to the above-described embodiments and modifications of the present invention are not limited to the above-described embodiments and modifications, and various modifications are possible within the scope of the claims. The electronic board units according to the present embodiments and modifications may be configured by appropriately combining the components of the above-described embodiments and modifications. [Explanation of symbols]

[0060] 10 Electronic board unit 20 Substrate 21 Mounting parts 22 Electronic Components 23 pin header 24 Horizontal Connector 30 Cover 31 Upper cover 32 Top part 33, 43 side wall 34 First engagement hole 35 Second engagement hole 36 Terminal hole 37, 47 Opening 41 Lower cover 42 Bottom part 51 First guide rail 52, 62 Vertical guide section 53, 63 Horizontal guide section 54, 64 Engagement protrusion 61 Second guide rail

Claims

1. A substrate on which a plurality of mounting components including electronic components are mounted; an upper cover for covering a surface of the board on which the mounted components are mounted; a lower cover that covers a surface of the substrate opposite to a surface covered by the upper cover; a first guide rail that is disposed on one of the upper cover and the lower cover, extends toward a side where the other of the upper cover and the lower cover is located, and engages with the other of the upper cover and the lower cover; a second guide rail that is disposed on one of the upper cover and the lower cover, extends toward a side where the other of the upper cover and the lower cover is located, engages with the other, and has a length in an extending direction longer than that of the first guide rail; An electronic board unit comprising:

2. The mounting component includes a pin header, a larger number of the pin headers are mounted on the board closer to the first guide rail than closer to the second guide rail; 2. The electronic board unit according to claim 1, wherein the upper cover is formed with terminal holes at positions corresponding to the pin headers, into which the pin headers are inserted.

3. The upper cover and the lower cover are formed to have a rectangular shape when viewed in a direction covering the substrate, The electronic board unit according to claim 1 , wherein the first guide rail and the second guide rail are disposed at diagonal positions of the rectangle.

4. The electronic board unit described in claim 3, wherein the first guide rail and the second guide rail each have a vertical guide portion extending along the direction of one side of the rectangle and a horizontal guide portion extending along the direction of a side perpendicular to the side.

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