JP5907159B2 - Structure for preventing incorrect assembly of old and new electronic units - Google Patents

Description

  The present invention relates to a structure for preventing erroneous assembly of an electronic unit in which a printed circuit board is accommodated in a case.

  Conventionally, in an electrical system of an automobile, an electronic unit in which a printed circuit board that constitutes a control circuit on which electronic components are mounted is housed in a case is mounted at an appropriate place so that electronic control of driving is performed. It has become. For example, Japanese Patent Laid-Open No. 2008-172889 (Patent Document 1) proposes an electronic unit such as an ECU that is detachable from an electric connection box body. According to such an electrical junction box, since the electronic unit has a separate structure from the electrical junction box, various types of electronic units with a built-in printed circuit board constituting a control circuit different for each vehicle type and grade are prepared. By doing so, it becomes possible to efficiently change the electronic unit according to the vehicle type and grade while sharing the electrical junction box body that bears the basic structure.

  By the way, when the case is the same and the types of printed circuit boards accommodated in the case are different, for example, when an electronic unit for the product number A is manufactured, the assembly that accommodates the printed circuit board for the product number B in the case is performed. May occur. Therefore, as a measure for preventing such erroneous assembly, as described in Japanese Patent Laid-Open No. 9-103090 (Patent Document 2), a product number distinguishing rib is protruded at a different position for each product number inside the case, When a printed circuit board having a different product number is mistakenly assembled in the case, it is generally performed that the product number distinguishing rib abuts against the printed circuit board or the electronic component to prevent the assembly.

  However, such a conventional misassembly prevention structure is effective when developing and designing multiple types of electronic units in which the case and the printed circuit board have substantially the same shape and different printed circuit board control circuits at the same time. However, there is a problem in that it does not function well to prevent erroneous assembly between an old-type electronic unit developed in advance and a new-type electronic unit newly developed as a successor.

  That is, since the old electronic unit has already been developed and designed, the case and the printed circuit board have already been manufactured, and design changes such as the addition of further ribs cannot be made substantially. . Therefore, if the product number distinguishing rib is protruded from the case of the new electronic unit and the printed circuit board is provided with a notch for accommodating the product number distinguishing rib, the printed circuit board of the old electronic unit is incorrectly assembled to the case of the new electronic unit. The printed circuit board of the old electronic unit interferes with the product number distinguishing ribs to prevent erroneous assembly. However, even if the printed circuit board of the new electronic unit is mistakenly assembled to the old case, no additional ribs can be added to the old case, so the new printed circuit board can be assembled and incorrect assembly cannot be prevented. The problem was inherent.

JP 2008-172889 A JP-A-9-103019

  The present invention has been made in the background of the above-mentioned circumstances, and the solution is to reliably prevent erroneous assembly between the previously developed old electronic unit and the newly developed new electronic unit. It is an object of the present invention to provide a new structure for preventing erroneous assembly of new and old electronic units.

  Hereinafter, embodiments of the present invention made to solve the above-described problems will be described. In addition, the component employ | adopted in each aspect as described below is employable by arbitrary combinations as much as possible.

  A first aspect of the present invention is a structure for preventing erroneous assembly of an old and new electronic unit that prevents an erroneous assembly between a previously developed old electronic unit and a newly developed new electronic unit. While the electronic unit has a structure in which an old printed circuit board is accommodated in an old case, the new electronic unit has a structure in which a new printed circuit board is accommodated in a new case. While the new case has a printed circuit board housing portion having substantially the same shape, the old printed circuit board and the new printed circuit board have substantially the same shape and different control circuits, and the printed circuit board of the new case While the housing part is provided with a part number distinguishing rib, the new printed circuit board is formed with a rib housing part for housing the part number distinguishing rib, and the new electronic unit includes: Serial wherein the interfering substrate-side contact part to the former case provided with the new printed circuit board is formed.

  According to this aspect, in the new electronic unit, the product number distinguishing rib is provided in the new case, and the rib accommodating portion is provided in the new printed circuit board. Therefore, when the new printed circuit board is assembled in the new case, the product number of the new case is provided. The discriminating rib is accommodated without interfering with the new printed circuit board, and normal assembly is completed. On the other hand, when the old printed circuit board is assembled to the new case, the product number distinguishing rib of the new case interferes with the old printed circuit board, thereby preventing erroneous assembly. Further, when the new printed circuit board is assembled to the old case, erroneous assembly is prevented by the substrate side contact portion provided on the new printed circuit board interfering with the old case. In this way, even if the old electronic unit has already been manufactured and no additional ribs can be provided, a simple structure is added to the new printed circuit board that provides a board-side contact that interferes with the old case. By doing so, it is possible to reliably prevent bidirectional misassembly between the old and new electronic units.

  Here, the part and shape of the old case where the board-side contact portion of the new printed circuit board interferes are not particularly limited, and a protrusion or the like provided in advance on the old case can be advantageously employed.

  The old and new cases and the old and new printed circuit boards have almost the same shape. Basically, the shape is the same in parts other than the part that demonstrates the wrong assembly prevention function, such as part number distinguishing ribs, rib housing parts, and board side contact parts. That is, there is a possibility that the old and new printed circuit boards may be misassembled in the old and new cases.

  According to a second aspect of the present invention, in the one described in the first aspect, the substrate-side contact portion provided on the new printed circuit board projects an outer peripheral edge of the new printed circuit board to the outer peripheral side. It is comprised by the overhang | projection part, and this overhang | projection part interferes with the board | substrate positioning rib protruded around the said printed circuit board accommodating part of the said old case.

  According to this aspect, in the old case, while skillfully utilizing the originally required board positioning ribs protruding around the printed board housing portion, the new printed circuit board can be brought into contact with the board positioning ribs. By providing the projecting portion by projecting the outer peripheral edge portion to the outer peripheral side, the substrate-side contact portion can be configured. Thereby, it is possible to reliably prevent the erroneous assembly of the old case to the new printed circuit board with a simple structure in which the overhanging part (substrate side contact part) is additionally provided on the new printed circuit board.

  According to a third aspect of the present invention, in the above-described second aspect, the overhang provided on the new printed circuit board is at least one corner of one side edge of the new printed circuit board. In addition, a cutout portion having the same shape as the overhang portion is formed at a position facing the overhang portion on the other side edge portion of the new printed circuit board facing the one edge portion. It is what.

  According to this aspect, the overhang portion can be advantageously provided by using an area having a small influence on the control circuit, that is, a corner portion of one side edge portion of the printed circuit board. In addition, since a cutout portion having the same shape as the overhanging portion is formed at a position facing the overhanging portion of the other side edge portion, the cut-out line when cutting out a plurality of new printed circuit boards from the workpiece size sheet By slightly bending the end portion, it is possible to form the overhanging portion on the new printed circuit board without changing the number of printed circuit boards taken out from the workpiece size sheet. Thereby, the structure which prevents the incorrect assembly | attachment which attaches a new printed circuit board to an old case can be added, without accompanying a cost improvement.

  According to a fourth aspect of the present invention, in the one described in the first aspect, the old electronic unit is provided with a protrusion on the printed circuit board housing portion of the old case, while the old printed circuit board has a protrusion. Has a protrusion accommodating portion for accommodating the protrusion, and the new electronic unit is not provided with the protrusion or the protrusion accommodating portion at the same position as the old case or the old printed circuit board. In the new printed circuit board, the board-side abutting portion is configured by a facing portion facing the protrusion of the old case, and the facing portion interferes with the protrusion of the old case.

  According to this aspect, the projection is provided in advance in the printed circuit board housing portion of the old case of the old electronic unit, and the projection housing portion for housing the projection is provided in advance on the old printed circuit board. In this case, the protrusion of the old case can be used as a product number distinguishing rib by not providing the new electronic unit with a protrusion or protrusion accommodating portion at the same position as the old case or the old printed circuit board. That is, since the new printed circuit board is not provided with the protrusion accommodating part corresponding to the protrusion of the old printed circuit board, this protrusion accommodating part non-formation region can be used as the substrate side contact part. Therefore, when the new printed circuit board is assembled to the old case, the substrate side contact portion provided on the new printed circuit board interferes with the old case, thereby preventing erroneous assembly.

  According to the present invention, in the new electronic unit, the product number distinguishing rib is provided in the new case, and the rib housing portion is provided in the new printed circuit board. Therefore, the product number distinguishing rib is accommodated without interfering with the new printed circuit board, and the normal assembly is completed. On the other hand, when the old printed circuit board is assembled to the new case, the product number distinguishing rib of the new case interferes with the old printed circuit board, thereby preventing erroneous assembly. Further, when the new printed circuit board is assembled to the old case, erroneous assembly is prevented by the substrate side contact portion provided on the new printed circuit board interfering with the old case. In this way, by adding a simple structure of providing a board-side contact part that interferes with the old case to the new printed board, it is possible to reliably prevent bidirectional misassembly between the old and new electronic units. Is possible.

The perspective view which shows the assembly | attachment middle state of the electrical-connection box comprised including the electronic unit as one Embodiment of this invention. The disassembled perspective view of the electronic unit shown in FIG. FIG. 3 is an exploded perspective view corresponding to FIG. 2, showing (a) a new electronic unit and (b) an old electronic unit. The perspective view which shows the assembly | attachment state of the case and printed circuit board shown in FIG. 3 ((a) regular assembly state, (b) incorrect assembly state). The top view for demonstrating how to cut out the board | substrate from the sheet | seat of a workpiece | work size ((a) new board | substrate, (b) old board | substrate). It is a figure which shows the other aspect of the printed circuit board of this invention, Comprising: The disassembled perspective view equivalent to FIG. 3 ((a) New electronic unit, (b) Old electronic unit). The perspective view which shows the assembly | attachment state of the case and printed circuit board shown in FIG. 6 ((a) regular assembly state, (b) incorrect assembly state).

  Embodiments of the present invention will be described below with reference to the drawings.

  1 to 5 show a structure in which the electronic unit 10 is assembled in a properly assembled state without erroneous assembly using the old and new electronic unit misassembly prevention structure according to the embodiment of the present invention.

  First, FIG. 1 shows an electrical junction box 12. The electrical junction box 12 is configured to include the main unit 14 and the electronic unit 10 according to the present invention separately from the main unit 14. The electrical connection box 12 includes a junction block, a fuse box, a relay box, and the like.

  As shown in FIG. 2, the electronic unit 10 has a structure in which a printed circuit board 18 is accommodated in a case 16 formed of synthetic resin. The case 16 has an upper case 20 and a lower case 22 each having a substantially rectangular box shape, which are opened, and are overlapped with each other covered with the other, and a lock portion 24 including a lock arm 24a and a lock 24b. It is set as the hollow box structure fixed by lock. The upper surface 26 and the lower surface 28 of the case 16 have a rectangular shape that is slightly smaller than the mounting surface 30 (see FIG. 1) of the main body 14, and when the electronic unit 10 is attached to the main body 14, The upper surface 26 is an overlapping surface with the mounting surface 30. In the following description, “upper” means the upper side in FIG. 2, and “lower” means the lower side in FIG.

  As shown in FIG. 2, the printed circuit board 18 accommodated in the case 16 has an electronic unit side connector connected to a main body side connector 32 (see FIG. 1) provided on a printed circuit board (not shown) of the main body 14. 34 and a side connection type connector 40 described later are provided. The electronic unit side connector 34 extends along one side edge 36 a of the printed circuit board 18, and is an opening hole penetrating the upper case 20 in a state where the printed circuit board 18 is accommodated in the case 16. 38 protrudes onto the upper surface 26 of the case 16. Further, as shown in FIG. 1, the electronic unit side connector 34 faces the main body side connector 32 in a state where the upper surface 26 of the case 16 faces the mounting surface 30 of the main body 14 in parallel. In the position, it protrudes toward the main body side connector 32.

  As shown in FIG. 1, the main unit 14 and the electronic unit 10 are assembled such that the electronic unit 10 is superimposed on the mounting surface 30 of the main body 14 with the upper surface 26 of the electronic unit 10 facing the mounting surface 30 of the main body 14. Is done. As a result, the electronic unit side connector 34 provided in the electronic unit 10 is inserted into the main body side connector 32 protruding from the mounting surface 30 of the main body 14, and the printed circuit board and the electronic unit 10 (not shown) of the main body 14 are inserted. The printed circuit board 18 is electrically connected. A side connection connector 40 projects from the side surface of the electronic unit 10, and a partner connector (not shown) is connected to the side connection connector 40.

  Next, referring to FIG. 3 and FIG. 4, an erroneous assembly prevention structure for new and old electronic units for preventing erroneous assembly between a newly developed new electronic unit 10A and a previously developed old electronic unit 10B. Detailed description. As shown in FIG. 3, the new electronic unit 10A has a structure in which the new printed circuit board 18A is accommodated in the new case 16A, while the old electronic unit 10B has the old printed circuit board 18B in the old case 16B. Contained structure.

  As shown in FIG. 3, the new lower case 22A constituting the new case 16A includes a new printed circuit board housing portion 42A, while the old lower case 22B constituting the old case 16B also includes the old printed circuit board housing portion 42B. The old and new printed circuit board housing portions 42A and 42B have substantially the same shape. Each of the old and new printed circuit board accommodating portions 42A and 42B has a substantially rectangular box shape that opens upward, and a substrate support portion for supporting the old and new printed circuit boards 18A and 18B at the center and peripheral edge of the bottom surface 44. A plurality of projections 46 are provided. In addition, in the peripheral area of the old and new printed circuit board accommodating portions 42A and 42B in which both end portions of the side edge portions 36c of the old and new printed circuit boards 18A and 18B are accommodated, the substrate positioning rib 48 corresponds to the shape of the old and new printed circuit boards 18A and 18B Projecting at different positions. That is, the board positioning rib 48 projecting from the new printed circuit board housing part 42A is more separated from the board positioning rib 48 projecting from the old printed circuit board housing part 42B than the overhanging part 54 of the new printed circuit board 18A described later. It is provided only in the back (left side in FIG. 3). As is clear from this, in the present embodiment, the size of the printed board housing portion 42 is limited to the side edge 50 side of the board positioning rib 48, and the small printed boards 18A and 18B are printed. It can be assembled at a predetermined position of the substrate housing portion 42. In addition, a product number distinguishing rib 52 that does not exist in the old printed board housing portion 42B is projected from a substantially central portion of the side edge portion where the board positioning rib 48 of the new printed board housing portion 42A is projected.

  On the other hand, the new printed circuit board 18A and the old printed circuit board 18B have substantially the same shape, and are configured to include different control circuits, that is, electronic circuits (not shown) in which various electronic components are mounted on a wiring pattern. Yes. However, unlike the old printed circuit board 18B, the new printed circuit board 18A is provided with an overhanging portion 54 in which the outer peripheral edge of the new printed circuit board 18A projects to the outer peripheral side at both corners of the side edge 36c. On the other hand, a cutout portion 56 having the same shape as the overhang portion 54 is formed at a position facing the overhang portion 54 in the side edge portion 36a opposite to the side edge portion 36c. Further, the new printed circuit board 18A is formed with a notch-shaped rib housing part 58 for housing the product number distinguishing rib 52 provided in the new printed circuit board housing part 42A. Further, screw through holes 60 for fixing the old and new printed circuit boards 18A and 18B to the old and new cases 16A and 16B are formed through the corners of the old and new printed circuit boards 18A and 18B.

  Next, referring to FIG. 4, (a) regular assembly and (b) incorrect assembly for the newly developed new electronic unit 10A and the previously developed old electronic unit 10B. Will be described in detail the assembled state of the printed circuit board 18 and the case 16 with respect to each. As described above, the electronic unit 10 includes the upper case 20, the printed circuit board 18, and the lower case 22. However, in order to facilitate understanding, the upper case 20 common to the old and new electronic units 10B and 10B is excluded in FIG. Are shown.

  First, in the case of regular assembly of the new electronic unit 10A as shown in the left diagram of FIG. 4A, that is, in the new printed circuit board housing portion 42A of the new lower case 22A constituting the new case 16A, a new print is made. When the board 18 </ b> A is assembled, the new printed board 18 </ b> A is inserted by inserting the product number distinguishing rib 52 into the rib housing portion 58 while the outer peripheral edge portion of the projecting portion 54 is in contact with the inside of the board positioning rib 48. The new printed circuit board accommodating portion 42A is accommodated while being positioned and arranged at a predetermined position. As described above, when the new electronic unit 10A is properly assembled, the new printed circuit board 18A is provided with the rib accommodating portion 58 for accommodating the product number distinguishing rib 52, and the board positioning rib is positioned at a position corresponding to the new printed circuit board 18A. 48, the product number distinguishing rib 52 does not interfere with the new printed circuit board 18A when the new printed circuit board 18A is assembled to the new printed circuit board housing part 42A of the new case 16A. It is accommodated in the rib accommodating portion 58 in a state where it is positioned and arranged at a predetermined position in 42A so that proper assembly can be performed.

  On the other hand, when the new electronic unit 10A is mistakenly assembled as shown in the left diagram of FIG. 4B, that is, the old printed circuit board is placed in the new printed circuit board accommodating portion 42A of the new lower case 22A constituting the new case 16A. When the 18B is assembled, the product number distinguishing rib 52 interferes with the side edge portion 36d of the old printed circuit board 18B, so that the old printed circuit board 18B is not well accommodated in the new printed circuit board accommodating section 42A. Therefore, erroneous assembly to the new electronic unit 10A is prevented.

  When the old electronic unit 10B is properly assembled as shown in the right side of FIG. 4A, that is, the old printed circuit board 18B is placed in the old printed circuit board accommodating portion 42B of the old lower case 22B constituting the old case 16B. When assembled, the old printed circuit board 18B is disposed in the old printed circuit board housing portion 42B while the outer peripheral edge portions of both end portions of the side edge portion 36c are in contact with the inside of the substrate positioning rib 48. It is accommodated in a state where it is positioned and arranged at a predetermined position in the printed circuit board accommodating portion 42B. Thus, in the case of regular assembly of the old electronic unit 10B, the old printed circuit board 18B is accommodated in the old printed circuit board housing part 42B without any problem so that regular assembly can be performed.

  On the other hand, when the old electronic unit 10B is mistakenly assembled as shown in the right side of FIG. 4B, that is, the new printed circuit board is accommodated in the old printed circuit board accommodating portion 42B of the old lower case 22B constituting the old case 16B. When 18A is assembled, the board positioning rib 48 projecting from the peripheral area of the old printed circuit board housing part 42B interferes with the overhanging part 54 of the new printed circuit board 18A, so that the old printed circuit board housing part 42B is interfered with. Are not well accommodated. Therefore, erroneous assembly to the old electronic unit 10B is prevented.

  In short, even if the old electronic unit 10B has already been manufactured and a new product number distinguishing rib or the like cannot be provided, the new printed circuit board 18A can be used by utilizing the board positioning ribs 48 that were originally in the old case 16B. When the old electronic unit 10B is misassembled by the simple means of providing the new printed circuit board 18A with a protruding portion 54 which is a board-side contact portion that interferes with the board positioning rib 48 when the old case 16B is misassembled to the old case 16B. It can prevent sticking. Therefore, bidirectional misassembly between the old and new electronic units 10A and 10B can be reliably prevented.

  Moreover, in the present embodiment, since the overhanging portion 54 is provided at the corner of the new printed circuit board 18A, the control circuit, the electronic unit side connector 34, and the side connection type connector 40 that constitute the new printed circuit board 18A. The influence of can be suppressed. Further, the side edge 36a of the new printed circuit board 18A is formed with a notch 56 having the same shape as the overhang 54 at a position facing the overhang 54, as shown in FIG. The old and new printed boards 18A and 18b can be made based on the old and new boards 64A and 64B cut out from the workpiece-size sheet 62 in substantially the same manner without waste. The substrate is cut out from the workpiece-size sheet 62 by a known processing technique such as mold processing. Therefore, since the number of cuts from the work-size sheet 62 can be made the same between the old and new boards 64A and 64B, the structure prevents the new printed board 18A from being erroneously assembled to the old electronic unit 10B without increasing the cost. A certain overhang 54 can be added.

  Next, other aspects of the old and new printed circuit boards 18A and 18B used in the old and new electronic units 10A and 10B of the present invention will be described in detail with reference to FIGS. 6 and 7, but the structure is the same as that of the above embodiment. About a member and a site | part, the detailed description is abbreviate | omitted by attaching | subjecting the code | symbol same as the said embodiment in the figure. That is, the old and new cases 16A and 16B in the present embodiment have exactly the same shape as the above embodiment, but the old and new printed circuit boards 66A and 66B exceed the circuit board positioning rib 48 of the previous embodiment, and the old and new printed circuit board housing portions 42A and 42B. It has a large size extending over the entire opening. Therefore, in this embodiment, the board positioning rib 48 of the above embodiment is a mere protrusion, and is different from the above embodiment in that a protrusion accommodating portion 70 for accommodating the protrusion 68 is formed on the old and new printed boards 66A and 66B. Yes.

  Next, with reference to FIG. 7, (a) a case where regular assembly is performed on a newly developed new electronic unit 10A and a previous electronic unit 10B which is developed in advance, and (b) incorrect assembly. The assembled state of the old and new printed circuit boards 66A and 66B and the old and new cases 16A and 16B will be described in detail. In FIG. 7, as in FIG. 4, the upper case 20 common to the old and new electronic units 10 </ b> B and 10 </ b> B is omitted for easy understanding.

  First, in the case of regular assembly of the new electronic unit 10A as shown in the left diagram of FIG. 7A, that is, in the new printed circuit board housing portion 42A of the new lower case 22A constituting the new case 16A, a new printed circuit board is provided. When the 66A is assembled, the product number distinguishing rib 52 and the projection 68 are inserted into the notch-shaped rib accommodating portion 58 and the notched-shaped projection accommodating portion 70 of the new printed circuit board 66A, respectively, so that the new printed circuit board 66A is newly printed. Since it is accommodated in the substrate accommodating portion 42A, the product number distinguishing rib 52 and the protrusion 68 can be assembled to the new case 16A without interfering with the new printed circuit board 66A, and regular assembly can be performed.

  On the other hand, in the case of incorrect assembly of the new electronic unit 10A as shown in the left diagram of FIG. 7B, that is, the old printed circuit board is placed in the new printed circuit board housing portion 42A of the new lower case 22A constituting the new case 16A. When 66B is assembled, the old printed circuit board 66B may not be well accommodated in the new printed circuit board accommodating part 42A due to interference of the product number distinguishing rib 52 and the projection 68 with the side edge 36d of the old printed circuit board 66B. It has become. Therefore, erroneous assembly to the new electronic unit 10A is prevented.

  Further, in the case of regular assembly of the old electronic unit 10B as shown in the right side view of FIG. 7A, that is, the old printed circuit board in the old printed circuit board housing portion 42B of the old lower case 22B constituting the old case 16B. When 66B is assembled, the projection 68 is inserted into the projection accommodating portion 70 of the old printed circuit board accommodating portion 42B, whereby the old printed circuit board 66B is accommodated in the old printed circuit board accommodating portion 42B. It can be assembled to the old case 16B without interfering with the substrate 66B, and regular assembly can be performed.

  On the other hand, when the old electronic unit 10B is mistakenly assembled as shown in the right side of FIG. 7B, that is, the new printed circuit board is accommodated in the old printed circuit board accommodating portion 42B of the old lower case 22B constituting the old case 16B. When 66A is assembled, the projection 68 interferes with the new printed circuit board 66A, so that the new printed circuit board 66A is not accommodated well in the old printed circuit board accommodating part 42B. That is, since the protrusions 68 are provided at different positions in the old and new cases 16A and 16B, the protrusion accommodating portion 70 for accommodating the protrusions 68 is of course not provided at the same position on the new and old printed boards 66A and 66B. . Therefore, in the new printed circuit board 66A, the facing portion that faces the protrusion 68 of the old case 16B interferes with the protrusion 68 of the old case 16B. In the present embodiment, the substrate-side abutting portion is configured by the facing portion. In this way, erroneous assembly to the old electronic unit 10B is prevented.

  In short, even if the old electronic unit 10B has already been manufactured and a new product number distinguishing rib or the like cannot be provided, the projection 68 (substrate positioning rib 48) originally provided in the old case 16B is used. When the new printed circuit board 18A is mistakenly assembled to the old case 16B, the projecting housing part 70 is disposed on the new printed circuit board 18A at the same position as the old printed circuit board 66B. It is possible to prevent erroneous assembly of the old electronic unit 10B by a simple means not provided. From the above, it has become possible to reliably prevent bidirectional misassembly between the old and new electronic units 10A and 10B.

  As mentioned above, although embodiment of this invention was explained in full detail, this invention is not limited by the specific description. For example, in the first embodiment, the overhanging portions 54 are provided at both corners of the side edge portion 36c of the new printed circuit board 18A, but it is only necessary to be provided at at least one corner. Further, the part of the old case 16B where the board-side contact part of the new printed circuit board 18A interferes with the board positioning rib 48, but the part of the old case 16B where the board-side contact part of the new printed circuit board 18A interferes, The shape is not particularly limited, and a protrusion or the like provided in advance on the old case 16B can be used.

  Note that “the old and new cases 16A and 16B and the old and new printed boards 18A and 18B have substantially the same shape” described in the first embodiment means that the product number distinguishing rib 52, the rib accommodating portion 58, the board side contact portion, and the like. This means that the shape is basically the same in the portion other than the portion exhibiting the function of preventing incorrect assembly, for example, the thickness between the old and new cases 16A and 16B and between the old and new printed boards 18A and 18B. Differences are naturally included in substantially the same shape.

  In the above-described two embodiments, the old and new cases 16A and 16B have a common shape in the first embodiment and the second embodiment, and accommodate old and new printed circuit boards 18A, 18B, 66A, and 66B of different sizes. However, the present invention can be similarly applied to old and new cases that simply accommodate old and new printed circuit boards of the same size. In that case, if there is a projection in the area of the old printed circuit board substrate housing portion of the old case, the substrate side contact portion can be provided by not providing the projection housing portion for housing the projection on the new printed circuit board. . If there are no protrusions in the area of the old printed circuit board housing part of the old case, provide a projecting part on the new printed circuit board, and project the board positioning ribs etc. provided outside the area of the old printed circuit board housing part of the old case. By abutting, the substrate side abutting portion can be provided.

  The rib accommodating portion 58 and the protrusion accommodating portion 70 are not limited to the cutout shape as illustrated, and may be a through hole or a recess as long as the substrate positioning rib 48 and the protrusion 68 can be accommodated.

10A: New electronic unit, 10B: Old electronic unit, 16A: New case, 16B: Old case, 18A, 66A: New printed circuit board, 18B, 66B: Old printed circuit board, 42: Printed circuit board housing portion, 48: Board positioning rib , 52: Product number distinguishing rib, 54: Overhang portion (substrate side contact portion), 56: Notch portion, 58: Rib accommodating portion, 68: Protrusion, 70: Protrusion accommodating portion

Claims (4)

It is a structure for preventing incorrect assembly of the old and new electronic units to prevent erroneous assembly between the previously developed old electronic unit and the newly developed new electronic unit,
The old electronic unit has a structure in which an old printed circuit board is accommodated in an old case, while the new electronic unit has a structure in which a new printed circuit board is accommodated in a new case,
While the old case and the new case are provided with a printed circuit board housing portion having substantially the same shape, the old printed board and the new printed circuit board have substantially the same shape and different control circuits,
While the printed circuit board housing portion of the new case is provided with a part number distinguishing rib, the new printed circuit board is formed with a rib housing part for housing the product number distinguishing rib,
The new electronic unit has a board-side contact portion that is provided on the new printed circuit board and interferes with the old case.   The board-side abutting portion provided on the new printed circuit board is configured by an overhanging part in which an outer peripheral edge of the new printed circuit board projects to the outer peripheral side, and the overhanging part is the print of the old case. 2. The structure for preventing erroneous assembly of old and new electronic units according to claim 1, wherein the structure interferes with substrate positioning ribs projecting around the substrate housing portion.   The overhanging portion provided on the new printed circuit board is provided at at least one corner of one side edge of the new printed circuit board, and is opposed to the one side edge of the new printed circuit board. 3. The structure for preventing erroneous assembly of old and new electronic units according to claim 2, wherein a cutout portion having the same shape as that of the overhang portion is formed at a side edge portion of the side edge portion so as to face the overhang portion. The old electronic unit is provided with a protrusion on the printed circuit board accommodating portion of the old case, while the old printed circuit board is provided with a protrusion accommodating portion for accommodating the protrusion.
The new electronic unit is not provided with the protrusion or the protrusion accommodating portion at the same position as the old case or the old printed circuit board,
2. The board-side contact portion is configured by a facing portion of the new printed circuit board facing the protrusion of the old case, and the facing portion interferes with the protrusion of the old case. Structure for preventing incorrect assembly of old and new electronic units described in 1.

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