JP5279126B2 - Circuit board fixing structure for vehicle instrument - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixing structure for a circuit board in a vehicular instrument capable of easily being assembled without increasing the number of components like screws, eliminating the problem of generating shaving dregs, and reducing burden to a circuit board. <P>SOLUTION: An engagement hook 11 and an engagement hole 12, which are engaged with each other without being brought into contact with the circuit board, are provided on positions further outside than the periphery of the circuit board 3 on a front cover 1 and a rear cover 2. When the front cover 1 and the rear cover 2 are connected to the corresponding positions of the inside vicinity of the periphery of the circuit board 3 of the front cover 1 and the rear cover 2, a pair of holding wall parts 14, 15 holding the inside vicinity of the periphery of the circuit board 3 from the front side and rear side are provided and the holding wall part 14 on the front cover and the holding wall part 15 on the rear cover are disposed with the circuit board 3 therebetween so as to be diagonally opposite to each other. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a circuit board fixing structure in a vehicle instrument.

  A vehicle such as an automobile is equipped with a meter equipped with a speedometer, a tachometer, a fuel gauge, a water temperature gauge, and the like. FIG. 3 is a cross-sectional view showing an example of a conventional vehicle instrument. In FIG. 3, 101 is a resin front cover, 102 is a resin back cover, and 103 is a circuit board.

  The circuit board 103 is accommodated in a space between the front cover 101 and the back cover 102, and the front end of the engagement hook 105 protruding from the back surface of the front cover 101 is engaged with the peripheral edge of the circuit board 103. The front cover 101 is fixed. Further, the back cover 102 is coupled to the front cover 101 with the circuit board 103 interposed therebetween by screwing the tip of the screw 110 penetrating the circuit board 103 into the boss portion of the front cover 101.

  FIG. 4 shows an example of a conventional circuit board fixing structure described in Patent Document 1. In FIG. 4, 111 is a front cover, 112 is a back cover, and 113 is a circuit board. The front cover 111 and the back cover 112 are coupled by engaging an engagement hook 121 protruding from the back cover 112 with an engagement hole 122 formed in the front cover 111. It is sandwiched between pressing protrusions 116 and 117 protruding from the inner surfaces of the front cover 111 and the back cover 112. In this case, the pressing projection 116 on the front cover 111 side and the pressing projection 117 on the back cover 112 side are provided with a shifted position. The peripheral edge of the circuit board 113 is in contact with the inclined edge of the rib 125 provided inside the engagement hook 121.

Japanese Patent Laid-Open No. 9-326567

  By the way, as shown in FIG. 3, when the engagement hook 105 is directly engaged with the circuit board 103, there is a problem that shavings are generated due to friction between the slope of the engagement hook 105 and the circuit board 103 during assembly. . Further, when the circuit board 103 is fixed with the screws 110, there are problems that the number of parts increases and the assembling work becomes troublesome.

  As shown in FIG. 4, when the circuit board 113 is sandwiched between the pressing protrusions 117 on the front cover 111 side and the pressing protrusions 116 on the back cover 112, which are displaced from each other, There was a possibility of causing bending and applying unnecessary stress. Further, since the peripheral edge of the circuit board 113 is brought into contact with the inclined edge of the rib 125 provided inside the engagement hook 121, the inclined edge of the rib 125 and the circuit board 113 are rubbed as in the example of FIG. There was a problem that shavings were generated by.

  The present invention has been made in view of the above-mentioned circumstances, and its purpose is to simplify the assembly without increasing the number of parts such as screws, and to eliminate the problem of scraping generation and to provide a circuit. An object of the present invention is to provide a circuit board fixing structure in a vehicle instrument that can reduce the burden on the board.

In order to achieve the above-described object, the circuit board fixing structure according to the present invention is characterized by the following (1) to (3).
(1) A circuit board fixing structure in a vehicle instrument in which the circuit board is fixed in the space inside the front cover and the back cover that form the exterior of the vehicle instrument,
When the circuit board is viewed from a direction orthogonal to a plane including the circuit board as a part, the front cover and the back cover are located at positions outside the peripheral edge of the circuit board. And an engaging portion and an engaged portion that are engaged with each other without contacting the circuit board to connect the back cover and the back cover,
When the circuit board is viewed from a direction perpendicular to a plane including the circuit board as a part thereof, the front cover and the back cover are respectively located at positions inside the peripheral edge of the circuit board. When the back cover and the back cover are combined, a pair of sandwiching wall portions that sandwich the inner periphery of the circuit board from the front side and the back side are provided,
The front cover side sandwiching wall portion and the back cover side sandwiching wall portion are provided so as to be disposed obliquely across the circuit board ,
Furthermore, the side wall surfaces of the holding wall portion on the front cover side and the holding wall portion on the back cover side facing the opposite sides in the direction along the plate surface of the circuit board are in relation to the plate surface of the circuit board. So that it is located on the same vertical plane set vertically .
(2) In the circuit board fixing structure configured as described in (1) above,
When the circuit board is viewed from a direction perpendicular to a plane including the circuit board as a part, the holding wall part on the back cover side is disposed outside the holding wall part on the front cover side, and the back cover The holding wall portion on the side is constituted by a corner portion of a bent wall having an L-shaped cross section where a wall perpendicular to the circuit board and a wall parallel to the circuit board intersect.
(3) In the circuit board fixing structure configured as described in (2) above,
When the front cover and the back cover are joined to a position inside the holding wall portion of the back cover when the circuit board is viewed from a direction orthogonal to a plane including the circuit board in part. A pressing projection that presses the circuit board toward the front cover side by pressing perpendicularly to the plate surface of the circuit board is provided.

According to the circuit board fixing structure configured as described in (1) above, the circuit board can be engaged with the engaging portion on the front cover side and the engaged portion on the back cover side without contact with the circuit board. It is possible to eliminate rubbing to the surface, and to solve the problem of scraping. Further, since the circuit board can be fixed without using screws, the number of parts can be reduced and the assembly can be facilitated. Also, by connecting the front cover and the back cover, the circuit board is sandwiched between the front cover side holding wall part and the back cover side holding wall part, but the front cover side holding wall part and the back cover side Since the sandwiching wall portion is arranged at a position diagonally across the circuit board, even if the pressing force to the circuit board by both sandwiching wall portions becomes considerably strong, the circuit board is not greatly bent, The burden on the circuit board can be reduced.
That is, since the corners and corners of both sandwiching wall portions are perpendicularly opposed to the substrate across the thickness of the circuit board, the sandwiching wall portions are in a relationship of regulating the positions of each other across the circuit board. The pressing force by the wall is offset. Therefore, the circuit board does not bend greatly. However, even though it is said that the corners of the sandwiching wall portions face each other across the circuit board and regulate the positions of each other, the contact surface of the sandwiching wall portion with respect to the circuit board is widened. The bending moment acts on the circuit board. Therefore, there is room for escape between the corners of both sandwiching wall portions, and both the sandwiching wall portions remain weakly restricted while slightly bending the circuit board by the action of the moment. Therefore, even if the dimensional accuracy of both sandwiching wall portions is set somewhat sweet, the engaging portion and the engaged portion can be flexibly engaged while absorbing the error, and the circuit board can be securely sandwiched. Thus, the burden on the circuit board can be reduced.
According to the circuit board fixing structure configured as described in (2) above, the corners of both sandwiching wall portions and the strong hits of the corners can be reduced by the bending of the vertical walls of the bent walls. Accordingly, it is possible to more flexibly absorb the error between the front cover and the back cover while allowing the engagement portion and the engaged portion to be engaged, and the circuit board can be securely clamped. The burden on the circuit board can be reduced.
According to the circuit board fixing structure having the configuration (3), it is possible to reduce the deflection of the central region of the circuit board.

  According to the present invention, it is possible to simplify the assembly without increasing the number of parts such as screws, to eliminate the problem of scraping, and to reduce the burden on the circuit board.

  The present invention has been briefly described above. Further, details of the present invention will be further clarified by reading through the modes for carrying out the invention described below with reference to the accompanying drawings.

It is a figure which shows the structure of the vehicle meter of embodiment of this invention, (a) is a whole sectional side view, (b) is an enlarged view of Ib part of (a). It is a figure for demonstrating the difference of the fixing structure of the circuit board of this invention, and the fixing structure shown as a comparative example, (a) is a figure of embodiment of this invention, (b) and (c) are figures of a comparative example. is there. It is a sectional side view which shows the example of the fixation structure of the circuit board in the conventional vehicle meter. It is sectional drawing which shows the example of the fixation structure of another conventional circuit board.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the drawings.

  1A and 1B are diagrams showing a configuration of a vehicle meter according to an embodiment, wherein FIG. 1A is an overall side sectional view, FIG. 1B is an enlarged view of an Ib portion of FIG. 2A, and FIG. 4A and 4B are diagrams for explaining a difference in fixing structure shown as a comparative example, in which FIG. 5A is a diagram of an embodiment of the present invention, and FIGS.

  In FIG. 1A, 1 is a front cover, 2 is a back cover, and 3 is a circuit board. The front cover 1 and the back cover 2 form the appearance of a vehicle instrument, and the circuit board 3 is fixed in the space inside. A transparent plate 4 is provided on the front surface of the front cover 1, and a pointer 6 driven by a movement 5 mounted on the circuit board 3 is disposed on the front surface side of the front case 1.

  In a place located outside the peripheral edge of the circuit board 3 of the front cover 1 and the back cover 2 (outside when the circuit board 3 is viewed from a direction orthogonal to a plane including the circuit board 3 in part), In order to connect the front cover 1 and the back cover 2, an engagement hook 11 and an engagement hole 12 (an engagement portion and an engaged portion) that are engaged with each other without contacting the circuit board 3 are provided. Further, at a position located inside the peripheral edge of the circuit board 3 of the front cover 1 and the back cover 2 (inside when the circuit board 3 is viewed from a direction orthogonal to a plane including the circuit board 3 in part). Is a pair of sandwiching wall portions 14 that sandwich the vicinity of the inner periphery of the peripheral edge of the circuit board 3 from the front side and the back side when the front cover 1 and the back cover 2 are joined using the engagement hook 11 and the engagement hole 12. 15 is provided. Further, when the front cover 1 and the back cover 2 are joined to a place inside the sandwiching wall portion 15 of the back cover 2, the circuit board 3 is pressed against the plate surface of the circuit board 3 by being pressed vertically. A cylindrical pressing projection 18 that presses toward the front cover 1 is provided in a protruding manner.

  The holding wall portion 14 on the front cover 1 side and the holding wall portion 15 on the back cover 2 side are disposed diagonally across the circuit board 3 as shown in FIG. Side wall surfaces 14 a and 15 a facing the opposite sides in the direction along the three plate surfaces are provided on the same vertical surface S set perpendicular to the plate surface of the circuit board 3. Further, the holding wall 15 (B) on the back cover 2 side is arranged outside the holding wall 14 (A) on the front cover 1 side, and the holding wall 15 (B) on the back cover 2 side The wall 15e perpendicular to the substrate 3 and the wall 15f parallel to the circuit substrate 3 intersect with each other to form a corner portion of a bent wall having an L-shaped cross section.

  When the circuit board 3 is fixed in this way, the engagement hole 12 on the front cover 1 side and the engagement hook 11 on the back cover 2 side can be engaged with the circuit board 3 in a non-contact manner. It is possible to eliminate rubbing to the surface, and to solve the problem of scraping. Further, since the circuit board 3 can be fixed without using screws, the number of parts can be reduced and the assembly can be facilitated.

  Further, by connecting the front cover 1 and the back cover 2, the circuit board 3 is held between the holding wall portion 14 (A) on the front cover 1 side and the holding wall portion 15 (B) on the back cover 2 side. However, the holding wall portion 14 (A) on the front cover 1 side and the holding wall portion 15 (B) on the back cover 2 side are arranged diagonally across the circuit board 3 and are opposite to each other. Since the side wall surfaces 14a and 15a facing the side are provided on the same vertical plane S set perpendicular to the plate surface of the circuit board 3, both sandwiching wall portions 14 (A) and 15 Even when the pressing force to the circuit board 3 due to (B) is considerably strong, the circuit board 3 can be prevented from being greatly bent, and the burden on the circuit board 3 can be reduced. Hereinafter, this point will be described with reference to FIG.

  In the case of the structure of the present invention shown in FIG. 2A, the circuit board 3 is not greatly bent even if the pressing force to the circuit board 3 by both sandwiching wall portions 14 (A) and 15 (B) becomes considerably strong. Thus, the burden on the circuit board 3 can be reduced. That is, since the corners a and b of the both sandwiching wall portions 14 (A) and 15 (B) are vertically opposed to the circuit board 3 across the thickness of the circuit board 3, both the sandwiching wall portions 14 (A) , 15 (B) are in a relationship in which their positions are regulated with respect to each other with the circuit board 3 interposed therebetween, and the pressing force by the both sandwiching wall portions 14 (A) and 15 (B) is offset. Therefore, the circuit board 3 is not greatly bent.

  However, even though the corners a and b of the sandwiching wall portions 14 (A) and 15 (B) are opposed to each other with the circuit board 3 interposed therebetween, the sandwiching wall portions 14 (A ), 15 (B) has a wide contact surface with respect to the circuit board 3, so that the bending moments Ma and Mb actually act on the circuit board 3. Therefore, there is room for escape between the corners a and b of the sandwiching wall portions 14 (A) and 15 (B) in a direction avoiding the collision, and the circuit is somewhat affected by the action of the moments Ma and Mb. Both bending wall parts 14 (A) and 15 (B) remain weakly regulated while the substrate 3 is bent. Therefore, even if the dimensional accuracy of both sandwiching wall portions 14 (A) and 15 (B) is set somewhat sweetly, the engaging means (the engaging hook 11 and the engaging hole 12) can be made flexible while absorbing the error. The circuit board 3 can be securely held and the load on the circuit board 3 can be reduced.

  On the other hand, when the clamping wall portion A and the clamping wall portion B are separated as in the comparative example of FIG. 2B, the clamping wall portion A and the clamping wall portion B are pressed against the circuit board 3 with respect to each other. The circuit board 3 can be pushed freely. Therefore, if the sandwiching wall part A and the sandwiching wall part B are protruding too much, the pressing of the sandwiching wall part A and the sandwiching wall part B becomes strong, and a large moment Ma, Mb acts on the circuit board 3. 3 becomes easy to bend. For example, the influence of the thickness error of the circuit board 3 and the height dimension accuracy of the sandwiching wall portions A and B is likely to be large. Accordingly, it is difficult to obtain the accuracy of the holding wall portions A and B and the engaging means C, and the front cover 1 and the back cover 2 can be flexibly engaged while absorbing the error, thereby securely holding the circuit board 3. It may not be possible.

  In addition, as in the comparative example of FIG. 2C, when the sandwiching wall portions A and B are in a relationship of wrapping with each other, the sandwiching wall portions A and B are completely facing each other. There is no room for escape. Therefore, the engagement state of the engagement means C is greatly influenced by the dimensional accuracy of the sandwiching wall portions A and B. For example, when the sandwiching wall portions A and B are in a tight relationship and receive a large reaction force, the engagement means C may not be engaged. Further, when the holding wall portions A and B are loosely connected, the pressing force against the circuit board 3 is not generated, and the circuit board 3 may not be securely held.

  On the other hand, in the case of the present invention shown in FIG. 2 (a), it can have an intermediate performance between (b) and (c), and the accuracy of the front cover 1 and the back cover 2 is not strictly controlled. The circuit board 3 can be securely fixed with flexibility, and the engaging means can be engaged without difficulty.

  In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably. In addition, the material, shape, dimensions, number, arrangement location, and the like of each component in the above-described embodiment are arbitrary and are not limited as long as the present invention can be achieved.

DESCRIPTION OF SYMBOLS 1 Front cover 2 Back cover 3 Circuit board 11 Engagement hook (engagement part or to-be-engaged part)
12 engagement hole (engagement part or engaged part)
14, A clamping wall portion 14a side wall surface 15, B clamping wall portion 15a side wall surface 15e vertical wall 15f parallel wall 18 pressing convex portion

Claims (3)

A circuit board fixing structure in a vehicle instrument in which a circuit board is fixed to a space inside the front cover and a back cover that form an appearance of the vehicle instrument,
When the circuit board is viewed from a direction orthogonal to a plane including the circuit board as a part, the front cover and the back cover are located at positions outside the peripheral edge of the circuit board. And an engaging portion and an engaged portion that are engaged with each other without contacting the circuit board to connect the back cover and the back cover,
When the circuit board is viewed from a direction perpendicular to a plane including the circuit board as a part thereof, the front cover and the back cover are respectively located at positions inside the peripheral edge of the circuit board. When the back cover and the back cover are combined, a pair of sandwiching wall portions that sandwich the inner periphery of the circuit board from the front side and the back side are provided,
The front cover side sandwiching wall portion and the back cover side sandwiching wall portion are provided so as to be disposed obliquely across the circuit board ,
Furthermore, the side wall surfaces of the holding wall portion on the front cover side and the holding wall portion on the back cover side facing the opposite sides in the direction along the plate surface of the circuit board are in relation to the plate surface of the circuit board. A circuit board fixing structure in a vehicle instrument, wherein the circuit board fixing structure is located on the same vertical plane set vertically .   When the circuit board is viewed from a direction perpendicular to a plane including the circuit board as a part, the holding wall part on the back cover side is disposed outside the holding wall part on the front cover side, and the back cover The side holding wall portion is configured by a corner portion of a bent wall having an L-shaped cross section where a wall perpendicular to the circuit board intersects with a wall parallel to the circuit board. Circuit board fixing structure in a vehicle instrument.   When the front cover and the back cover are joined to a position inside the holding wall portion of the back cover when the circuit board is viewed from a direction orthogonal to a plane including the circuit board in part. The vehicular instrument according to claim 2, wherein a pressing projection that presses the circuit board toward the front cover side by pressing perpendicularly to the plate surface of the circuit board is projected. Circuit board fixing structure.

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