Substrate housing case

Abstract

Provided is a substrate housing case that makes it possible to suppress twisting of a terminal caused by thermal expansion and thermal contraction while preventing complication of an assembling process of a substrate and without using a special terminal.　A substrate housing case 1 includes: a case member 10; terminals 3A, 3B each having an inner connection part 31 and an outer connection part 32; and a fitting member 40. The case member has an opening part 13. The fitting member integrally has a terminal holding part 41 and a fixing part 42, and is fitted into the opening part while closing the opening part by the terminal holding part in a state in which a gap G is left between an end edge 14 of the opening part and the terminal holding part and being fixed to the case member by the fixing part. The terminal has the outer connection part projecting to the outside of the case member, and has the inner connection part connected and fixed to a substrate B. At least some of the terminals serve as fitting part holding terminals 3A penetrating the terminal holding part and held by the fitting member.

Description

Circuit board storage case

[0001] The present disclosure relates to a substrate housing case.

[0002] Substrates configured as plate-shaped electrical connection members, such as printed circuit boards including electronic control units (ECUs), are often housed in cases for use in vehicles and other applications. Terminals that can establish electrical connections between external electrical connection members, such as connectors, and the substrate housed in the case are often incorporated in such substrate housing cases. Providing terminals in the substrate housing case allows electrical connection between external conductive members, such as electric wires and wiring harnesses, and components on the substrate via the terminals from outside the case.

[0003] FIG. 3 shows a schematic cross-sectional view of an example of such a board housing case, a board housing case 9 configured as a conventional ECU case. The board housing case 9 includes a resin case member 90 and a case lid 92, and houses a printed circuit board B including an ECU inside. A plurality of terminals 3A, 3B configured as press-fit terminals are attached to the case member 90. Each of the terminals 3A, 3B has a board connection portion 31 with a press-fit structure at one end and a terminal connection portion 32 at the other end that can be connected to an external connector terminal. Each of the terminals 3A, 3B penetrates the case member 90, with the terminal connection portion 32 protruding outside the case member 90. The board connection portions 31 of the terminals 3A, 3B are press-fitted into through holes B1 in the printed circuit board B. Some of the terminals (3B) have terminal connection portions 32 that are directly connected to external equipment D, and other terminals (3A) have terminal connection portions 32 that are detachably connected to an external connector, such as a connector provided at the tip of a wire harness. The terminals 3A, 3B are usually fixed to the case member 90 by insert molding (mold fixing), and the terminals 3A, 3B are firmly held in place by the constituent material of the case member 90.

[0004] JP 2019-79681 A JP 2015-210938 A JP 2013-4239 A JP 2010-123415 A

[0005] 3 , when terminals 3A and 3B attached to a board case 9 are fixed to a case member 90 near terminal connection portions 32 and connected to a board B at board connection portions 31, which are spaced apart from terminal connection portions 32, and when the assembly of board case 9 and board B experiences a temperature change, the difference in thermal expansion coefficients between case member 90 and board B causes relative displacement between case member 90 and board B in an in-plane direction (including the horizontal and depth directions in the figure). This can cause terminals 3A and 3B to become twisted. In other words, in terminals 3A and 3B, leg portions 33 connecting board connection portions 31 and terminal connection portions 32 are tilted, causing uneven force to be applied to the contact points between board connection portions 31 and board B (contact points between the inner wall surfaces of through-holes B1 and terminals 3A and 3B). If the terminals 3A, 3B are twisted, a load is generated at the connection points between the terminals 3A, 3B and the board B, which can result in problems such as poor connection, including the terminals 3A, 3B coming out of the through-holes B1, and an increase in contact resistance due to repeated sliding caused by the relative displacement, vibration, etc. The larger the board B and case member 90 are, the longer the distance between the board B and the case member 90 is, and the larger the environment in which the ambient temperature changes, the more likely it is that the terminals 3A, 3B will be twisted due to thermal expansion and contraction, and the more likely the problems caused by this will become.

[0006] One possible solution to alleviate terminal twisting caused by thermal expansion and contraction in a board housing case is to add a structure to the board housing case that can mitigate terminal displacement. For example, as shown in FIG. 4, adding a pedestal connector 95 to the board housing case 9′ is considered. The pedestal connector 95 is a resin block molded into the middle of the terminals 3A, collectively holding the terminals 3A at their middle portions. The pedestal connector 95 is also referred to as a holding base, and is disclosed, for example, in Patent Document 1, although for a different purpose. When the pedestal connector 95 is provided, the relative positions of the terminals 3A are maintained by the pedestal connector 95, eliminating the need to firmly fix the terminals 3A to the board housing case 9′. Instead, a gap g can be provided between the board housing case 9′ and each terminal 3A. The presence of this gap g mitigates the effects of relative displacement on the terminals 3A, even if a temperature change causes relative displacement between the board B and the case member 90′. As a result, the terminals 3A are less likely to be twisted. However, when the pedestal connector 95 is provided in this manner, the process of housing and assembling the board B in the board housing case 9' becomes complicated. Specifically, as in the board housing case 9 of Figure 3, if a pedestal connector is not provided, the terminals 3A, 3B are fixed to the case member 90, and then the board B is assembled to the case member 90 by inserting the terminals 3A, 3B into the through holes B1, etc., whereas when the pedestal connector 95 is provided, it is necessary to create an assembly in which multiple terminals 3A are fixed to the pedestal connector 95, and then attach this assembly to the board B, and then assemble the board B to the case member 90'. In this way, the provision of the pedestal connector 95 requires a process that is significantly different from that when a pedestal connector is not provided.

[0007] Another approach to reducing terminal wrenching caused by thermal expansion and contraction in a board housing case is to provide the terminal with a structure capable of absorbing relative displacement between the case member and the board. An example of a terminal with such a structure is a terminal with a bendable portion, as disclosed in Patent Document 2. The bendable portion is provided on the leg of the press-fit terminal as a portion having a plastic deformation initiation load smaller than the plastic deformation initiation load of the press-fit portion (board connection portion). Specifically, the bendable portion is formed by narrowing the leg. Patent Document 2 describes a bendable portion that is intended to bend to absorb misalignment when the press-fit portion of the press-fit terminal and the through-hole are press-fitted while misaligned. Providing a similar bendable portion in a terminal provided in a board housing case is expected to achieve a similar effect in suppressing terminal wrenching caused by thermal expansion and contraction.

[0008] Another example of a terminal with a structure capable of absorbing relative displacement between a case member and a board is the terminal with a bent portion disclosed in Patent Document 3. The bent portion is formed as a portion having at least one bent shape on at least a portion of the leg of the press-fit terminal. In Patent Document 3, the bent portion is formed for the purposes of following misalignment with the through hole and increasing durability against temperature changes and vibration. However, by providing a similar bent portion in a terminal to be mounted in a board housing case, it is expected that a similar effect can be achieved in suppressing twisting of the terminal due to thermal expansion and thermal contraction.

[0009] Thus, forming a board housing using terminals with a structure capable of absorbing misalignment, such as the bendable portion of Patent Document 2 or the bent portion of Patent Document 3, may be effective in suppressing terminal twisting due to thermal expansion and contraction. However, in this case, terminals with special shapes are required, making it impossible to construct a board housing case using general-purpose terminals. Furthermore, there are concerns about reduced terminal strength and reduced workability when assembling a board into a board housing case. For example, when using the structure of Patent Document 2, the strength of the constricted bendable portion is reduced, which may result in insufficient strength of the terminals to withstand the applied load when press-fitting the terminals fixed to the case member into the through-holes of the board to assemble the board. Furthermore, when using the structure of Patent Document 3, the bent portion may be bent, making it impossible to apply a load along the axial direction of the leg and press-fit the terminals into the through-holes using a general jig during assembly. Therefore, special methods and devices are required, such as inserting a jig to apply a load from the side of the leg, as in the terminal holding portion of an insertion device disclosed in Patent Document 4.

[0010] In view of the above, the object of the present invention is to provide a substrate storage case that has terminals that are connected to a substrate stored inside, and that can suppress twisting of the terminals due to thermal expansion and contraction while minimizing the complexity of the substrate assembly process and without using special terminals.

[0011] The substrate storage case of the present disclosure is a substrate storage case that fixes and stores a substrate that is configured as a plate-shaped electrical connection member, and includes a case member made of a material with a different thermal expansion coefficient from the substrate, at least one terminal that has two electrical connection portions, an inner connection portion and an outer connection portion, that are spaced apart and integral with each other, and an engaging member, wherein the case member has an opening as a through hole in a wall surface, and the engaging member has a terminal holding portion and a fixing portion integral with the opening, and the terminal holding portion closes the opening while leaving a gap between the edge of the opening and the terminal holding portion, and the engaging member is fixed to the case member by the fixing portion and fitted into the opening, and each of the terminals has the outer connection portion protruding outside the case member and the inner connection portion connected and fixed to the substrate, and at least a portion of the terminal passes through the terminal holding portion to become an engaging portion-retained terminal held by the engaging member.

[0012] The substrate storage case according to the present disclosure is a substrate storage case equipped with terminals that are connected to the substrate stored inside, and is a substrate storage case that can suppress twisting of the terminals due to thermal expansion and contraction while minimizing the complexity of the substrate assembly process and without using special terminals.

[0013] Fig. 1 is a schematic cross-sectional view showing the structure of a board housing case according to one embodiment of the present disclosure. Fig. 2 is an enlarged view showing a state in which an external connector is attached to the board housing case. Fig. 3 is a schematic cross-sectional view showing the structure of a conventional general board housing case. Fig. 4 is a schematic cross-sectional view showing the structure of a board housing case to which a pedestal connector is applied.

[0014] [Description of the embodiment of the present disclosure] First, the embodiment of the present disclosure will be described.

[0015] [1] The substrate storage case of the present disclosure is a substrate storage case that fixes and stores a substrate configured as a plate-shaped electrical connection member, and includes a case member made of a material having a different thermal expansion coefficient from that of the substrate, at least one terminal having two electrical connection portions, an inner connection portion and an outer connection portion, spaced apart and integral with each other, and a mating member, wherein the case member has an opening as a through hole in a wall surface, and the mating member has a terminal holding portion and a fixing portion integral with the opening, and the terminal holding portion closes the opening while leaving a gap between the edge of the opening and the terminal holding portion, and the fixing portion is fixed to the case member and fitted into the opening, and each of the terminals has the outer connection portion protruding outside the case member and the inner connection portion connected and fixed to the substrate, and at least a portion of the terminal passes through the terminal holding portion to form a mating portion-retained terminal held by the mating member.

[0016] In the above-described board housing case, an opening is provided in the case member, and a mating member is fitted into the opening. At least a portion of the terminal penetrates the terminal holding portion of the mating member, and the board is connected and fixed to the board inside the board housing case. Because a gap is left between the edge of the opening of the case member and the terminal holding portion of the mating member, even if relative displacement occurs between the board and the case member due to the difference in the thermal expansion coefficients of the board and the case member when the board housing case housing the board undergoes thermal expansion or contraction due to temperature changes, the gap can absorb the displacement. Therefore, the terminals are less susceptible to the relative displacement between the board and the case member, and prying at the internal connection portion connected and fixed to the board is also less likely to occur. Therefore, even when the board housing case is used in an environment prone to temperature changes, problems caused by prying, such as poor terminal connection and increased contact resistance due to the application of uneven loads, are suppressed. Terminals with special structures, such as constricted or bent structures, are not required to suppress terminal prying. Furthermore, the process of assembling the board housing case and assembling the board involves fixing the fitting member with the terminals attached to the edge of the opening of the case member with the fixing portion, and then assembling the board to the case member by appropriately performing necessary operations such as press-fitting the terminals into the through-holes, just as in the case of a conventional general board housing case in which the terminals are fixed directly to the case member. Therefore, compared to conventional board housing cases, the process of assembling the board is not significantly more complicated.

[0017] [2] In the aspect [1] above, the case member may have a connection peripheral wall integral with the wall surface, surrounding the outer edge of the opening and erected outside the wall surface, and the mating member may be fitted inside the area surrounded by the connection peripheral wall. In this case, the connection peripheral wall can be used as a connector positioning member when connecting an external connector to the outer connection portion of the mating-portion-retained terminal held by the mating member. Furthermore, if the connector has a housing that surrounds the entire area surrounded by the connection peripheral wall and a seal member is disposed between the connector housing and the connection peripheral wall, the board housing case can be made waterproof. This allows the board housing case to be used in places where it may come into contact with moisture, such as the exterior of an automobile. There is no need to apply a waterproofing treatment to the area between the mating member and the case member located inside the area surrounded by the connection peripheral wall, as the gap remains. This gap can be effectively used to absorb displacement due to thermal expansion and contraction.

[0018] [3] In the above aspect [1] or [2], the fixing portion may be configured to fix the mating member to the case member by engaging with the edge of the opening. This allows the mating member to be stably fixed to the case member by the fixing portion while maintaining a gap between the terminal holding portion of the mating member and the edge of the opening. Furthermore, this allows the mating member to be easily attached to the case member.

[0019] [4] In any of the above aspects [1] to [3], the substrate may be configured as a printed circuit board, and each of the terminals may be configured as a press-fit terminal having an inner connection portion with a press-fit structure, and the inner connection portion may be press-fitted into a through-hole in the printed circuit board. In this case, the substrate housing case can be suitably used as a case for housing a printed circuit board, such as an ECU case. When an inner connection portion with a press-fit structure is press-fitted into a through-hole in a printed circuit board, if a relative displacement between the case member and the substrate causes misalignment of the insertion axis of the inner connection portion, prying is likely to occur. However, the substrate housing case according to the embodiment of the present disclosure includes a fitting member and further provides a gap between the fitting member and the case member, thereby mitigating the impact on the terminals of thermal expansion and contraction of the case member and the substrate, and effectively suppressing prying of the terminals.

[0020] [5] In any of the above aspects [1] to [4], the board housing case may include, as the terminals, in addition to the mating-portion-retaining terminals, wall-surface-retaining terminals provided in a region of the case member other than the region where the opening is provided, penetrating the wall surface. In the board housing case according to the embodiment of the present disclosure, as described above, a mating member is fitted into the opening of the case member, and a gap is provided between the terminal-retaining portion of the mating member and the edge of the opening. Therefore, even if relative displacement occurs between the case member and the board due to thermal expansion or contraction, the gap can be used to absorb the displacement. The effect of absorbing displacement extends not only to the mating-portion-retaining terminals that penetrate the mating member, but also to the wall-surface-retaining terminals that penetrate the case member. Therefore, the occurrence of prying due to the relative displacement can be suppressed in both the mating-portion-retaining terminals and the wall-surface-retaining terminals.

[0021] [6] In the aspect [5] above, the mating portion holding terminal may be detachably connected to an external connector terminal, and the wall surface holding terminal may be directly connected to an external device. In this case, electrical signals input from the external connector terminal to the board via the mating portion holding terminal can be appropriately processed within the board, and the external device can be controlled via the wall surface holding terminal. As described above, the occurrence of prying due to the relative displacement is suppressed in both the mating portion holding terminal and the wall surface holding terminal, so that the operation of the board, including signal input from the connector terminal and device control, can be stably maintained inside the board housing case.

[0022] [Details of the embodiment of the present disclosure] A board housing case according to an embodiment of the present disclosure will be described in detail below with reference to the drawings. The board housing case according to the embodiment of the present disclosure is a case that securely houses a board and includes terminals. Electrical connection can be established between an electrical connection member outside the board housing case and the board via the terminals. The board housing case can also be considered a case-integrated connector.

[0023] The types of the board and terminals constituting the board housing case according to the embodiment of the present disclosure are not particularly limited. The board may be any plate-shaped electrical connection member, but the following will focus on a form in which the board is a printed circuit board equipped with an electronic control unit (ECU). The terminals may be any terminals having an outer connection portion and an inner connection portion spaced apart from each other and integrated together, but the following will focus on a form in which the terminals are press-fit terminals. In this case, the board housing case serves as an ECU case that houses a printed circuit board and can be connected to an external connector.

[0024] 1 is a schematic cross-sectional view of an ECU case 1 as an example of a board housing case according to an embodiment of the present disclosure, with a printed circuit board B housed inside. Furthermore, FIG. 2 is a partially enlarged view showing a state in which an external connector C is connected to the ECU case 1.

[0025] The ECU case 1 has a case member 10 and a case lid 20 that are separable from each other, and the case member 10 and the case lid 20 form a hollow box structure. The case member 10 has a roughly rectangular box shape with one side (the bottom side in the figure) open, and the open side is covered by the case lid 20. The case member 10 and the case lid 20 are fixed to each other by fixing members (not shown) such as screws.

[0026] A printed circuit board B (hereinafter, sometimes simply referred to as the board) is housed in the ECU case 1. The board B is arranged parallel to the upper wall surface 11 of the case member 10 and the case lid 20. The board B is fixed to the case member 10 as appropriate by fixing members (not shown) such as screws.

[0027] The constituent materials of the case member 10 and the substrate B have different coefficients of thermal expansion (linear expansion coefficients). The case member 10 is preferably made of a resin material such as polybutylene terephthalate (PBT), similar to conventional general substrate housing cases. The substrate B is made of the same material as conventional general printed circuit boards, and is usually made of a rigid substrate such as FR-4 material. In many cases, resin materials such as PBT have a higher coefficient of thermal expansion than rigid substrates. In other words, when heated to the same temperature, the case member 10 expands more than the substrate B. Furthermore, when cooled to the same temperature, the case member 10 shrinks more than the substrate B.

[0028] At least one, preferably two or more, terminals 3A, 3B are attached to the case member 10. In the illustrated embodiment, five terminals 3A, 3B are attached. Each of the terminals 3A, 3B has two electrical connection portions, an inner connection portion 31 and an outer connection portion 32, which are spaced apart and integral with each other. Here, each of the terminals 3A, 3B is configured as a press-fit terminal. That is, each of the terminals 3A, 3B has a board connection portion with a press-fit structure as the inner connection portion 31. By press-fitting the inner connection portion 31 into a through-hole B1 of a printed circuit board B along the axial direction, an electrical connection can be established with the inner wall surface of the through-hole B1. In the illustrated embodiment, the inner connection portion 31 has a needle-eye press-fit structure and each has a pair of resilient contact pieces that protrude outward in the width direction. Meanwhile, each of the terminals 3A, 3B has a terminal connection portion as the outer connection portion 32 that can be electrically connected to an external connector terminal C2. In the illustrated embodiment, the outer connection part 32 has the structure of a male terminal for mating connection. The inner connection part 31 and the outer connection part 32 are joined together by a leg part 33 along the axial direction where the inner connection part 31 is press-fitted into the through hole B1.

[0029] The case member 10 has an opening 13 formed as a through-hole formed by removing a portion of the constituent material of the upper wall surface 11. The shape of the opening 13 is not particularly specified, but it may be formed, for example, as a substantially rectangular through-hole. A mating member 40 is fitted into the opening 13. The mating member 40 integrally includes a terminal holding portion 41 and a fixing portion 42. The terminal holding portion 41 is a flat plate-shaped region. The terminal holding portion 41 has a shape that matches the opening 13, such as a substantially rectangular shape. As will be described later, the terminal holding portion 41 closes the opening 13 of the case member 10 and holds the terminal 3A. The fixing portion 42 is a portion that can be fixed to the case member 10, and the mating member 40 is fixed to the case member 10 at the fixing portion 42. The fixing portion 42 is not particularly limited in terms of its specific structure or the manner in which it is fixed to the case member 10, as long as it can stably maintain the state in which the fitting member 40 is fitted in the opening 13, but it is preferable that the fixing portion 42 be configured as a locking portion that can be locked onto the edge 14 of the opening 13. In the illustrated embodiment, the fixing portion 42 is provided as a locking portion formed respectively above and below the fitting member 40 in the thickness direction, and is locked onto the smooth edge 14 of the opening 13 above and below.

[0030] The material of the mating member 40 is not particularly limited, but it is preferable that it has a higher coefficient of thermal expansion than the substrate B, and is particularly preferably made of a resin material. The mating member 40 may be made of the same resin material as the case member 10, but is preferably made of a material with a lower flexural modulus than the case member 10 so that it can be easily fitted into the opening 13 and the fixing portion 42, which serves as a locking portion, can be easily engaged. However, from the perspective of stably holding the terminal 3A, it is preferable that the mating member 40 be made of a hard resin material rather than a soft polymer such as rubber or elastomer.

[0031] Furthermore, although optional, a connection peripheral wall 12 is integrally provided on the top wall surface 11 of the case member 10. The connection peripheral wall 12 surrounds the outside of the edge 14 of the opening 13 (outside the area surrounded by the edge 14) and stands on the outer surface of the top wall surface 11 of the case member 10. For example, the connection peripheral wall 12 has an inner dimension slightly larger than the edge 14 of the opening 13 and is configured as an upwardly standing cylindrical wall. As will be described later, the connection peripheral wall 12 defines the connector opening when connecting an external connector C to the terminal 3A, and functions as a positioning member for the connector C.

[0032] The mating member 40 is fixed to the upper wall surface 11 of the case member 10 at the fixing portion 42 and fitted into the opening 13 of the case member 10, with the terminal holding portion 41 closing the opening 13. However, a gap G is left between the terminal holding portion 41 and the edge 14 of the opening 13. The size and shape of the gap G are not particularly specified, but it is preferable to leave a gap G large enough to not be completely closed even after thermal expansion and thermal contraction of the case member 10 and the board B within the range of temperature changes expected in the environment in which the ECU case 1 accommodating the board B is installed. Furthermore, it is preferable to provide a gap G over the entire area where the outer edge of the fixing portion 42 faces the edge 14 of the opening 13, except for areas where no gap is provided due to the fixation of the mating member 40 by the fixing portion 42. The entire mating member 40, including the terminal holding portion 41 and the fixing portion 42, is contained within the area surrounded by the connection portion peripheral wall 12. The thickness of the mating member 40 may be the same as or different from the thickness of the upper wall surface 11 of the case member 10, but it is preferable that when the mating member 40 is mated in the opening 13, at least a portion of the thickness of the terminal holding portion 41 overlaps with the thickness of the upper wall surface 11 of the case member 10.

[0033] Each of the terminals 3A, 3B provided on the ECU case 1 has an outer connection portion 32 protruding outside the case member 10. The inner connection portion 31 is connected and fixed to the board B. That is, the inner connection portion 31, which has a press-fit structure, is press-fit into a through hole B1 of the printed circuit board B. At least some of the terminals 3A, 3B are mating-portion-retained terminals 3A. Optionally, the terminals that are not mating-portion-retained terminals 3A are wall-surface-retained terminals 3B.

[0034] The fitting portion retention terminal 3A penetrates the terminal retention portion 41 of the fitting member 40 fitted into the opening 13 of the case member 10 and is held by the fitting member 40. Preferably, the fitting portion retention terminal 3A penetrates the terminal retention portion 41 at a position of the leg 33 closer to the outer connection portion 32 than the axial center and is held by the fitting member 40. The fitting portion retention terminal 3A is held at two points: the point where it penetrates the fitting member 40 and the point where the inner connection portion 31 is connected and fixed to the board B, and does not directly come into contact with the constituent material of the case member 10. In the illustrated embodiment, multiple fitting portion retention terminals 3A are held by a common fitting member 40. The specific form in which the terminal 3A is held by the mating member 40 is not particularly limited, but by using methods such as press-fitting into a through hole formed thinner than the leg 33 or insert molding (mold fixing), it is sufficient that the terminal 3A can be firmly held by the mating member 40 with a strength that does not create a gap larger than the gap G between the mating member 40 and the case member 10 between the mating member 40 and the terminal 3A.

[0035] The wall-retained terminals 3B are held by the case member 10 by penetrating the upper wall surface 11 of the case member 10 in an area other than the area where the openings 13 are formed and the fitting members 40 are fitted into the openings 13. Preferably, the wall-retained terminals 3B are held by the case member 10 by penetrating the upper wall surface 11 of the case member 10 at positions of the legs 33 closer to the outer connecting portions 32 than the axial center. The specific manner in which the terminals 3B are held by the case member 10 is not particularly limited, but it is sufficient that the terminals 3B are firmly held by the upper wall surface 11 by a method such as press-fitting into through holes formed thinner than the legs 33 or insert molding, with a strength such that a gap larger than the gap G between the upper wall surface 11 and the terminals 3B is not created.

[0036] In the ECU case 1, the fitting portion holding terminal 3A is detachably connected to a connector terminal C2 provided on an external connector C. On the other hand, the wall surface holding terminal 3B is directly connected to an external device D. More specifically, it is directly connected to an electrode or terminal (not shown) provided on the external device D. Once the wall surface holding terminal 3B is connected to the device D, it is basically maintained in this connected state. When the outer connection portions 32 of the terminals 3A and 3B are configured as mating male terminals, the connector terminal C2, which serves as the mating terminal, and the electrode or terminal provided on the device D have a female structure that can be fitted and connected to the male terminal.

[0037] 2 shows an example of a state in which connector terminals C2 of an external connector C are connected to the outer connection portion 32 of the mating portion holding terminal 3A. A plurality of terminals 3A held by the terminal holding portion 41 of a common mating member 40 constitute a connector connection portion that is collectively connected to the multi-pole connector C. The connected connector C has a structure in which a plurality of connector terminals C2 are held inside a housing C1 made of a resin material, and is coupled to the tip of a wire harness (not shown). Inside the housing C1, the plurality of connector terminals C2 are arranged corresponding to the plurality of mating portion holding terminals 3A.

[0038] The connector C is connected to the ECU case 1 with the housing C1 surrounding the entire area surrounded by the connection portion peripheral wall 12 from outside the connection portion peripheral wall 12 of the case member 10. At this time, the connection portion peripheral wall 12 of the case member 10 functions as a positioning member for locating the connector C in a predetermined position. The outer connection portions 32 of the fitting portion holding terminals 3A protruding inside the area surrounded by the connection portion peripheral wall 12 are each fitted and connected to the connector terminals C2 of the positioned connector C. If waterproofing is required for the ECU case 1, it is advisable to place a seal member S, such as an O-ring made of waterproof rubber, between the connection portion peripheral wall 12 and the housing C1.

[0039] <Effects of Temperature Changes> In the ECU case 1 according to this embodiment, as described above, the case member 10 is provided with an opening 13, and the mating member 40 is disposed in the opening 13. The mating member 40 is attached to the case member 10 by the fixing portion 42, with a gap G remaining between the terminal holding portion 41 and the edge 14 of the opening 13. At least some of the terminals 3A, 3B that constitute the board housing case 1 are mating-portion-held terminals 3A held by the mating member 40. With this configuration, the ECU case 1 according to this embodiment can reduce the effects on the terminals 3A, 3B of thermal expansion and contraction of the case member 10 and the board B. The mechanism is as follows.

[0040] Because the case member 10 and the board B have different thermal expansion coefficients, when the ECU case 1, with the board B fixed and housed therein, is subjected to a temperature change, the upper wall surface 11 of the case member 10 and the board B thermally expand and contract at different rates. If the case member 90 does not have an opening or a mating member attached, as in the conventional board housing case 9 shown in Figure 3, a relative displacement occurs between the upper wall surface of the case member 90 and the board B in an in-plane direction (including the horizontal and depth directions in the figure). This results in forces of different magnitudes and / or directions being applied to the terminals 3A and 3B between the location where the terminals 3A and 3B penetrate the case member 90 and are held by the case member 90 and the location where the terminals 3A and 3B are connected and fixed to the board B by the inner connection portion 31, which is spaced apart from the location along the leg portion 33. This force acts to tilt the connection direction of the inner connection portion 31 to the board B, i.e., the insertion axis along which the press-fit structure of the inner connection portion 31 is press-fitted into the through hole B1 of the printed circuit board B. This action may cause twisting of the terminals 3A and 3B. In other words, the inner connection portion 31 is connected to the board B with its axis tilted, causing an uneven load to be applied to the connection point between the inner connection portion 31 and the board B. For example, only a portion of the inner connection portion 31 having the press-fit structure may be pressed excessively strongly against the inner surface of the through hole B1. The effects of twisting include physical connection failure, such as the terminals 3A and 3B coming out of the through hole B1. Furthermore, when the terminals 3A and 3B are subjected to the relative displacement or vibration described above in a twisted state, repeated micro-sliding occurs at the electrical connection point between the board B and the terminals 3A and 3B (the contact point of the inner connection portion 31 with the inner surface of the through hole B1), resulting in an increase in contact resistance. These phenomena reduce the reliability of the connection between the terminals 3A, 3B and the substrate B.

[0041] In contrast, in the ECU case 1 according to this embodiment shown in FIG. 1 , a gap G is provided between the edge 14 of an opening 13 provided in a portion of the case member 10 and the mating member 40 fitted into the opening 13. Therefore, even if relative displacement occurs between the case member 10 and the board B due to thermal expansion and contraction when the ECU case 1, with the board B fixed and housed therein, is subject to temperature changes, at least a portion of the relative displacement can be absorbed by the gap G. In other words, expansion, contraction, and / or movement of the mating member 40 and / or the case member 10 within the gap G makes it difficult for the relative displacement between the case member 10 and the board B to be transmitted to the terminals 10 in the form of tilt or load application. In other words, the force applied to the terminals 3A and 3B due to the relative displacement between the case member 10 and the board B can be kept small. This reduces the likelihood of the terminals 3A and 3B being twisted. As a result, connection problems related to prying, such as poor connection between the board B and the terminals 3A, 3B, including the terminals 3A, 3B coming out of the through-holes B1, and an increase in contact resistance due to repeated sliding, are less likely to occur, and high connection reliability is maintained between the terminals 3A, 3B and the board B. The effect of suppressing prying by the fitting member 40 and the gap G is greatest in the fitting-portion-retained terminals 3A that are held by the fitting member 40 itself, but a certain degree of effect is also achieved in the wall-retained terminals 3B. This is because the effect of the gap G, which reduces relative displacement with respect to the board B, extends to the entire upper wall surface 11 of the case member 10.

[0042] By suppressing the effects of temperature changes on the terminals 3A, 3B in this manner, the ECU case 1 according to this embodiment is particularly suitable for use in environments prone to large and frequent temperature changes, such as the interior of an automobile, housing a circuit board B. The ECU case 1 according to this embodiment suppresses the terminals 3A, 3B from being twisted due to temperature changes by using the fitting member 40 and ensuring the gap G, but does not utilize the characteristics of the terminals 3A, 3B themselves to suppress twisting. Therefore, any terminals may be used as the terminals 3A, 3B. It is not necessary to use terminals with special structures, such as the constricted bend-permitting portion described in Patent Document 2 or the bent portion described in Patent Document 3. Instead, general-purpose terminals, such as those with simple rod-shaped legs 33, may be used.

[0043] In order to maintain a high effect of preventing the terminals 3A, 3B from being twisted, it is preferable not to place any substance such as an adhesive or a sealant in the gap G between the edge 14 of the opening 13 of the case member 10 and the mating member 40 for the purpose of fixing the mating member 40 or providing waterproofing. Even without such a substance, the mating member 40 can be fixed to the case member 10 by a fixing portion 42 provided on the mating member 40. Furthermore, waterproofing of the ECU case 1 can be achieved by providing a waterproof structure outside the edge 14 of the opening 13. For example, as shown in FIG. 2 , a waterproof structure can be achieved by providing a portion of the housing C1 facing the connection portion peripheral wall 12 erected around the opening 13 to form the mating connector C, and by placing a sealant S between the housing C1 and the connection portion peripheral wall 12. This easily achieves both the gap G and waterproofing. By making the case member 10 waterproof, the ECU case 1 housing the substrate B can be used in locations where it may come into contact with water, such as in the engine compartment or around the suspension of an automobile. In these locations, where temperature changes are large, it is advantageous to be able to achieve both waterproofing and the prevention of terminals 3A, 3B from being twisted due to temperature changes. It is also conceivable that the positioning member of the connector C, which corresponds to the connection peripheral wall 12, could be configured as part of the mating member 40 and fitted into the large opening 13. However, in this case, it would be difficult to ensure waterproofing.

[0044] <Assembly of the Board Storage Case and Installation of the Board> Here, a brief description will be given of the method for assembling the ECU case 1 and the method for installing the board B in the ECU case 1. To assemble the ECU case 1, first, a terminal that will become the fitting portion holding terminal 3A is installed in the fitting member 40. For example, a through hole that is narrower than the leg portion 33 of the terminal 3A may be provided in the terminal holding portion 41 of the fitting member 40, and the terminal 3A may be press-fitted into the through hole. Alternatively, the fitting member 40 may be manufactured by insert molding while incorporating the leg portion 33 of the terminal 3A. The terminal holding portion 41 of the fitting member 40 needs to be formed in a shape and size that will fit within the opening 13 of the case member 10, leaving a gap G.

[0045] Next, the resulting assembly of the mating portion holding terminal 3A and mating member 40 is attached to the case member 10. At this time, an opening 13 is formed in the case member 10 in advance, and the wall surface holding terminal 3B is attached by insert molding or the like as appropriate. When attaching the mating member 40 to the case member 10, the mating member 40 is fitted into the opening 13 while the fixing portion 42, which serves as a locking portion, is elastically deformed as appropriate. The fixing portion 42 is then engaged with the edge 14 of the opening 13, thereby fixing the mating member 40 to the case member 10.

[0046] Next, the board B, which has undergone necessary processing such as the mounting of chip components, is assembled to the case member 10 to which the mating member 40 and terminals 3A, 3B have been attached. When assembling the board B, the inner connection portions 31 of the terminals 3A, 3B, which have a press-fit structure, are press-fit into the predetermined through-holes B1 on the board B, and the board B is housed in the internal space of the case member 10. Finally, the opening of the case member 10 is closed with the case lid 20.

[0047] In the case of the conventional board housing case 9 shown in FIG. 3 , the board B is assembled to the case member 90 to which the terminals 3A and 3B are pre-assembled while the inner connection portions 31 of the terminals 3A and 3B, which have a press-fit structure, are press-fit into the through-holes B1. In other words, in the case of the ECU case 1 according to the present embodiment described above, if the mating member 40 to which the terminals 3A are pre-assembled is attached to the case member 10, the subsequent assembly of the board B can be performed using the same process as in the case of the conventional board housing case 9 that does not have the mating member 40, and the assembly process is not significantly complicated. Furthermore, the assembly can be performed using the same jigs and devices as in the conventional board housing case 9. This differs from the configuration using the pedestal connector 95 shown in FIG. 4 , in which the assembly of the pedestal connector 95 and the terminals 3A must first be attached to the board B before assembling the board B to the case member 90′. Furthermore, in the ECU case 1 according to this embodiment, there is no need to provide the terminals 3A, 3B with low-strength portions, such as the constricted bend-tolerant portion of Patent Document 2, in order to suppress twisting, which reduces concerns about damage to the terminals 3A, 3B due to the effect of the load when the inner connection portion 31 is press-fitted into the through-hole B1 of the board B. There is no need to provide the terminals 3A, 3B with a structure that would prevent the application of a load along the axial direction of the leg portion 33, such as the bent portion having a bent shape as in Patent Document 3, so there is no need to use special jigs or devices for assembling the board B.

[0048] <Other Configurations> Finally, we will briefly explain possible configurations of the board housing case of the present disclosure other than the configuration described above with reference to Figures 1 and 2. In the configuration shown above, the board B is configured as a printed circuit board, and the terminals 3A and 3B are press-fit terminals having press-fit board connection portions as the inner connection portions 31. The board connection portions are press-fit connected to through holes B1 of the printed circuit board B. However, the configurations of the board and terminals are not limited to these. For example, the inner connection portions of the terminals may be configured for surface mounting (connection by soldering to the board surface) or through-hole mounting (connection by soldering a rod-shaped terminal inserted into a through-hole). When connecting the terminals using solder, the inner connection portions of the terminals are firmly fixed to the board, just as in the case of a press-fit connection. Therefore, if a mating member is not used, the terminals are more likely to become twisted due to thermal expansion and contraction of the board and case members. Therefore, even in a configuration in which the inner connection portion is connected and fixed by soldering, similar to the configuration using the press-fit connection described above, by adopting a structure in which a gap is secured in the opening of the case member and the mating portion is fitted into the gap, the effect of suppressing twisting of the terminal is effectively achieved. Even when soldering is used, if twisting of the terminal occurs, repeated stress is applied to the solder joint, which may affect the solder joint, such as causing cracks, so it is effective to suppress twisting of the terminal by using a mating member. When connecting and fixing the terminal to the board by soldering, the board does not necessarily have to be a printed circuit board, and any plate-shaped electrical connecting member such as a bus bar can be used.

[0049] When the internal connection portions of the terminals are connected to the board by soldering, the method of assembling the board to the case member to which the fitting member and terminals are attached can be, for example, by temporarily fixing the case member and the board and then using flow solder to connect and fix the internal connection portions of each terminal attached to the case member to the board. Alternatively, reflow solder can be placed in advance at the locations on the board where the internal connection portions will be provided, and the board can be temporarily fixed to the case member and reflowed by heating to connect and fix the internal connection portions of each terminal to the predetermined locations. In this case, reflow connection and fixation can also be performed simultaneously on components other than terminals, such as chip components.

[0050] Furthermore, in the embodiment described above, the case member 10 is configured such that the connection peripheral wall 12 is provided on the outside of the opening 13 into which the mating member 40 is fitted, and the seal member S is disposed between the connection peripheral wall 12 and the housing C1 of the connector C. However, if waterproofing is not required, the seal member can be omitted. In that case, the connection peripheral wall does not necessarily have to be provided.

[0051] In the embodiment described above, the fixing portion 42 of the mating member 40 is provided as a locking portion that locks onto the edge 14 of the opening 13. By adopting such a configuration for the fixing portion 42, the mating member 40 can be stably and easily fixed to the case member. However, the structure of the fixing portion and the method for fixing the mating member to the case member are not limited to this. For example, the fixing portion may be provided as a flat flange-like portion, and the fixing portion may be fixed to the case member using adhesive, screws, or other fixing members.

[0052] Although the embodiments of the present disclosure have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the gist of the present invention.

[0053] DESCRIPTION OF SYMBOLS 1 ECU case (board housing case) 10 Case member 11 Upper wall surface 12 Connection portion peripheral wall 13 Opening 14 Edge of opening 20 Case lid 3A (fitting portion holding) terminal 3B (wall surface holding) terminal 31 Inner connection portion (board connection portion) 32 Outer connection portion (terminal connection portion) 33 Leg portion 40 Fitting member 41 Terminal holding portion 42 Fixing portion 9, 9' Board housing case 90, 90' Case member 92 Case lid 95 Base connector B (Printed circuit) board C External connector C1 Housing C2 Connector terminal D Device G Gap S Sealing member g Gap

Claims

1. A board storage case for fixing and storing a board configured as a plate-like electrical connection member, comprising: a case member made of a material with a different thermal expansion coefficient from that of the board; at least one terminal having two electrical connection portions, an inner connection portion and an outer connection portion, spaced apart and integrally formed, and a mating member; wherein the case member has an opening as a through-hole in a wall surface; and the mating member has an integral terminal holding portion and a fixing portion, and the terminal holding portion closes the opening, leaving a gap between the edge of the opening and the terminal holding portion, and the fixing portion is fixed to the case member and fitted into the opening; and wherein each of the terminals has the outer connection portion protruding outside the case member and the inner connection portion connected and fixed to the board, and at least a portion of the terminal passes through the terminal holding portion to form a mating portion-retained terminal held by the mating member.

2. A circuit board storage case as described in claim 1, wherein the case member has a connection peripheral wall that surrounds the outside of the edge of the opening and stands on the outside of the wall surface, and is integral with the wall surface, and the fitting member is fitted inside the area surrounded by the connection peripheral wall.

3. A substrate storage case as described in claim 1 or claim 2, wherein the fixing portion fixes the fitting member to the case member by engaging with the edge of the opening.

4. A board storage case as claimed in claim 1 or claim 2, wherein the board is configured as a printed circuit board, and each of the terminals is configured as a press-fit terminal with an inner connection portion having a press-fit structure, and the inner connection portion is press-fitted into a through-hole in the printed circuit board.

5. A substrate storage case as described in claim 1 or claim 2, wherein the terminals include, in addition to the fitting portion holding terminal, a wall surface holding terminal that penetrates the wall surface in an area of ​​the case member other than where the opening is provided.

6. The circuit board case according to claim 5, wherein the fitting portion holding terminal is detachably connected to an external connector terminal, and the wall surface holding terminal is directly connected to an external device.

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