JPH0677282U - Circuit board sealing structure - Google Patents

Abstract

(57) [Abstract] [Purpose] It is possible to reduce the jig manufacturing cost that has been conventionally required, reduce the man-hours for operating the jig, and fix the circuit board 2 To provide a circuit board sealing structure capable of improving the flatness of the circuit board. [Structure] A circuit board 2 on which an electronic component 1 is mounted, and a cap 4 for hermetically sealing the circuit board 2 include a chassis 50.
In the sealing structure of the circuit board fixed to the chassis 5,
Protrusions 51, 52 for positioning the cap 4 with respect to 0 and the circuit board 2 with respect to the chassis 50
Is formed on the chassis 50.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a circuit board sealing structure, and more specifically, for airtightly sealing the circuit board on which electronic components such as sensors are mounted, for positioning a cap with respect to a chassis and positioning the circuit board. The present invention relates to a circuit board sealing structure.

[0002]

[Prior art]

 FIG. 5 is a perspective view schematically showing a chassis in a conventional circuit board sealing structure, and FIG. 6 is a perspective view schematically showing a chassis, a circuit board and a cap in a conventional circuit board sealing structure. It is a figure.

The chassis 3 is made of a metal plate in which isosceles triangular portions 24 are integrally formed on both short sides of the rectangular portion 25, and each of the isosceles triangular portions 24 has a hole 16 near the apex thereof. Are formed one by one. On the upper surface of the rectangular portion 25, a rectangular protrusion 26 smaller than the rectangular portion 25 is formed by pressing. The lead wire 5 is glass-sealed (hermetically sealed) along the long side at a predetermined position, for example, at five positions near one long side of the protrusion 26 along the long side.

A ceramic circuit board 2 on which an electronic component 1 such as a sensor is mounted has a rectangular shape smaller than the protruding portion 26, and connection lines 27 are provided at five positions on the circuit board 2, for example. Books are connected one by one.

The cap 4 is a box-shaped metal cover, and the rectangle formed by the inner side of the lower side wall 29 of the cap 4 is adapted to coincide with the outer periphery of the protrusion 26.

FIG. 7 and FIG. 8 schematically show a state in which the chassis 3 is placed on the jig 6 and the circuit board 2 is fixed on the chassis 3 in the conventional circuit board sealing structure. FIG.

First, the jig 6 will be described with reference to FIG. The jig 6 is configured to include a generally rectangular substrate 7 made of stainless steel and an overlapping portion 8, and the substrate 7 and the overlapping portion 8 are connected by hinges 9 at predetermined two positions on the long side. The board 7 and the overlapping portion 8 can be closed by these hinges 9 as shown by the arrow X, or opened up to an angle of about 130 degrees. FIG. 7 schematically shows the hinge 9 opened to an angle of about 130 degrees, and FIG. 8 schematically shows the hinge 9 closed and the overlapping portion 8 superposed on the substrate 7. ing. From the bottom surface side of the substrate 7, four screws 31 are screwed by the nut 30 and these screws 31 serve as legs for supporting the substrate 7.

A base 11 is formed substantially in the center of the substrate 7 in parallel with the long side of the substrate 7. On the base 11, a protrusion 10 is vertically provided at a predetermined position. Further, a plate-shaped holding piece 12 and a holding piece 22 are fixed in parallel on the substrate 7 so as to sandwich the base 11 at a position separated from the base 11 by a predetermined distance. A recess 13 is formed at a predetermined position on the base 11 side of the sandwiching piece 12 and the sandwiching piece 22. The recesses 13 of the sandwiching piece 12 and the sandwiching piece 22 are opposed to each other across the base 11. Is formed in. Holes 18 or elongated holes 28 are provided at predetermined positions of the groove 21 formed by the base 11 and the sandwiching piece 12.

On the other hand, on the long side of the overlapping portion 8 where the hinges 9 are not attached, substantially U-shaped protruding portions 14 are extended at equal intervals. The tip portion 23 of the projecting portion 14 and a notch portion 15 described later are arranged in a straight line. A notch 15 cut out in a substantially U-shape is formed near the root of each protruding part 14, and each notch 15 has a length between the protruding parts 14 located on the left side of the notch 15. It is divided into a side surface 19 and a short side surface 20 located on the right side of the cutout portion 15. The distance between the long side surface 19 and the other long side is slightly smaller than the distance between the short side surface 20 and the other long side.

Next, a procedure for fixing the circuit board 2 on the chassis 3 using the jig 6 will be described.

First, in order to fix the chassis 3 onto the jig 6, the substrate 7 and the overlapping portion 8 are opened as shown in FIG. 7, and the protrusion 10 is inserted into one hole 16 of the chassis 3. Then, the chassis 3 is placed on the base 11. When the protrusion 10 is penetrated through the one hole 16 in this manner, both long sides of the rectangular portion 25 come into contact with the sandwiching piece 12 and the sandwiching piece 22, and the chassis 3 is fixed on the base 11. After fixing the chassis 3 on the base 11, the overlapping portion 8 is closed to the substrate 7 side as shown in FIG. Next, while contacting one long side of the circuit board 2 with the long side surface 19, one corner of the circuit board 2 with the notch 15, and the other corner of the circuit board 2 with the tip 23, respectively. Is placed on the upper surface of the protrusion 26, the circuit board 2 is positioned, and the circuit board 2 is fixed at that position using an adhesive.

Next, a procedure for hermetically sealing the circuit board 2 fixed on the chassis 3 will be described.

After the circuit board 2 is fixed on the chassis 3, the cap 4 is covered on the circuit board 2 while the inner wall 32 of the cap 4 is in contact with the outer periphery of the protrusion 26, and the cap 4 is positioned with respect to the chassis 3. The circuit board 2 can be hermetically sealed by welding the lower side wall 29 to the rectangular portion 25 at that position.

[0014]

[Problems to be solved by the device]

 If the circuit board 2 is hermetically sealed while the position of the circuit board 2 with respect to the chassis 3 is incorrect in the manufacturing process of hermetically sealing the circuit board 2 on which the electronic component 1 such as a sensor is mounted, the lead wire 5 and the circuit If the electric connection with the substrate 2 becomes unstable, or if the cap 4 is welded on the rectangular portion 25 while the position of the cap 4 with respect to the chassis 3 is incorrect, this welding can be made strong. In some cases, the airtightness of the circuit board 2 may be impaired. As described above, a product in which the circuit board 2 is hermetically sealed on the chassis 3 while the positioning of the cap 4 with respect to the chassis 3 and the positioning of the circuit board 2 are inaccurate is highly likely to be a defective product. 2 must be accurately positioned with respect to chassis 3. Due to these needs, conventionally, in the process of hermetically sealing the circuit board 2, the jig 6 is used to accurately position the circuit board 2 with respect to the chassis 3, and the protruding portion formed on the chassis 3 is used. The cap 4 was accurately positioned with respect to the chassis 3 by 26.

As described above, in the conventional circuit board sealing structure, the dedicated jig 6 is required, the manufacturing cost of the jig 6 is high, and the number of steps for operating the jig 6 is large. In addition to the above, since the protrusions 26 are formed on the chassis 3 by pressing, there is a problem that the flatness of the protrusions 26 is poor and the adhesion of the circuit board 2 to the chassis 3 is poor.

The present invention has been made in view of the above problems, and can reduce the manufacturing cost of the jig, reduce the man-hours for operating the jig, and fix the circuit board. It is an object of the present invention to provide a circuit board sealing structure capable of improving the flatness of a surface.

[0017]

[Means for Solving the Problems]

 In order to achieve the above object, a circuit board sealing structure according to the present invention comprises a circuit board having electronic components mounted thereon and a circuit board having a cap fixed to the chassis for hermetically sealing the circuit board. In the sealing structure, a protrusion for positioning the cap with respect to the chassis and positioning the circuit board with respect to the chassis is formed on the chassis.

[0018]

[Action]

 According to the circuit board sealing structure having the above configuration, the positioning of the circuit board, which needs to be hermetically sealed to the chassis, is accurately performed by the protrusions, and a jig that has been conventionally required is omitted. Therefore, not only the manufacturing cost of the jig is cut, but also the number of steps for operating the jig is reduced. Moreover, the cap accurately positions the cap with respect to the chassis without the need for a rectangular projection for positioning the cap, which has been conventionally required, and the circuit board is not subjected to any processing. And the flatness of the surface on which the circuit board is fixed is improved.

[0019]

【Example】

 An embodiment of a circuit board sealing structure according to the present invention will be described below with reference to the drawings. It should be noted that components having the same functions as those of the conventional example are designated by the same reference numerals.

FIG. 1 and FIG. 2 are a partial sectional plan view and a side sectional view schematically showing a chassis, a circuit board and a cap in a circuit board sealing structure according to a first embodiment.

The chassis 50 is made of a metal plate in which isosceles triangular portions 24 are integrally formed on both short sides of the rectangular portion 25, and the rectangular portion 25 is provided at a predetermined number of, for example, five locations in the vicinity of one long side thereof. At the position, the lead wire 5 is glass-sealed (hermetically sealed) to the chassis 50 along this long side. Then, four protrusions 51 and two protrusions 52 are formed on the upper surface side by pressing at predetermined positions of the rectangular portion 25, and the protrusions 51 are used for positioning the circuit board 2 with respect to the chassis 50. The protrusion 52 is used for positioning the cap 4 with respect to the chassis 50.

The ceramic circuit board 2 on which the electronic component 1 is mounted has a rectangular shape smaller than the rectangular portion 25, and the connecting wires 27 from the lead wires 5 are provided at five positions on the circuit board 2, for example. Books are connected one by one.

The cap 4 is a box-shaped metal cover, and the lower side wall 29 of the cap 4 is finished flush.

Next, a procedure for fixing the circuit board 2 at an accurate position on the chassis 50 will be described.

The circuit board 2 is arranged on the upper surface of the rectangular portion 25 while a pair of long and short side surfaces of the circuit board 2 are brought into contact with the respective protrusions 51, the circuit board 2 is positioned, and an adhesive is used. The circuit board 2 is fixed at that position. By fixing the circuit board 2 to the upper surface of the rectangular portion 25 in this manner, the circuit board 2 is not covered with the lead wires 5, and the position of the circuit board 2 with respect to the chassis 50 can be always accurate. After fixing the circuit board 2 to the upper surface of the rectangular portion 25, the connection wires 27 are connected and fixed to one end of each lead wire 5 and the pad portion on the circuit board 2 side.

Next, a procedure for hermetically sealing the circuit board 2 fixed on the chassis 50 will be described.

When the cap 4 is put on the chassis 50 while the inner wall 32 of the cap 4 is in contact with all of the protrusions 51 and 52, the position of the cap 4 with respect to the chassis 50 becomes accurate. After the position of the cap 4 with respect to the chassis 50 is made accurate, the lower side wall 29 is welded to the rectangular portion 25 to surely hermetically seal the circuit board 2.

As described above, in the circuit board sealing structure according to the first embodiment, the circuit board 2 that needs to be hermetically sealed by the protrusions 51 and 52 can be accurately positioned with respect to the chassis 50. Since the jig 60, which has been conventionally required, is omitted, the manufacturing cost of the jig 60 can be reduced and the number of steps for operating the jig 60 can be reduced. Moreover, the projections 51 and 52 can accurately position the cap 4 on the rectangular portion 25 without the need for the rectangular projection portion 26 on the upper surface of the chassis 3 which is conventionally required. It can be directly fixed to the upper surface of the rectangular portion 25 which has not been processed. Therefore, the flatness of the surface to which the circuit board 2 is fixed can be improved, and the adhesion of the circuit board 2 to the chassis 50 can be improved.

FIG. 3 and FIG. 4 are a partial sectional plan view and a side sectional view schematically showing the chassis, the wiring board and the cap in the circuit board sealing structure according to the second embodiment.

The chassis of the second embodiment is different from the chassis 50 of the first embodiment in the number of the protrusions 51 and 52 and the arrangement method. That is, the protrusions 41 are formed on the upper surface by pressing at a total of four predetermined positions of the rectangular portion 25 of the chassis 40, and these protrusions 41 are formed on the upper and lower sides of the circuit board 2 and the lower side of the long and short pairs of the cap 4. It is arranged at a position for positioning the wall 29, and these projections 41 are commonly used for positioning the circuit board 2 and the cap 4 with respect to the chassis 40.

To fix the circuit board 2 in the correct position on the chassis 40, the circuit board 2 is placed on the upper surface of the rectangular portion 25 while the two side surfaces of the circuit board 2 are brought into contact with all of these protrusions 41. The circuit board 2 is positioned on the upper surface of the rectangular portion 25, and the circuit board 2 is fixed at that position using an adhesive. By fixing the circuit board 2 on the upper surface of the rectangular portion 25 in this manner, the circuit board 2 is not covered with the small holes 17, and the position of the circuit board 2 with respect to the chassis 40 can be always accurate.

Next, in order to hermetically seal the circuit board 2 fixed on the chassis 40, the two inner walls 32 of the cap 4 are brought into contact with all the protrusions 41, and the other two inner walls 32 of the cap 4 are attached. By bringing the cap 4 into contact with the side wall of the circuit board 2, the position of the cap 4 with respect to the chassis 40 becomes accurate. If the lower side wall 29 is welded to the rectangular portion 25 while the position of the cap 4 with respect to the chassis 40 is kept accurate, the circuit board 2 is reliably hermetically sealed.

As described above, in the circuit board sealing structure according to the second embodiment, the circuit board 2 that needs to be hermetically sealed by the protrusions 41 can be accurately positioned with respect to the chassis 40, and is conventionally required. Since the existing jig 60 is omitted, the manufacturing cost of the jig 60 can be cut and the number of steps for operating the jig 60 can be reduced. In addition, the projection 41 can accurately position the cap 4 on the rectangular portion 25 without requiring the rectangular projection 26 on the upper surface of the chassis 3 which is conventionally required, and the circuit board 2 is not processed. It can be fixed directly on the upper surface of the rectangular portion 25 which is not open. Therefore, the flatness of the surface to which the circuit board 2 is fixed can be improved, and the adhesion of the circuit board 2 to the chassis 50 can be improved. Further, the number of the protrusions 41 can be reduced as compared with the case of the first embodiment, the manufacturing of the chassis 40 can be simplified, and the cost can be further reduced.

[0034]

[Effect of device]

 As described above in detail, in the circuit board sealing structure according to the present invention, the circuit board on which the electronic component is mounted and the cap for hermetically sealing the circuit board are fixed to the chassis. Further, in the circuit board sealing structure, a protrusion for positioning the cap with respect to the chassis and positioning the circuit board is formed on the chassis. Since the circuit board that needs to be hermetically sealed by the protrusion can be accurately positioned with respect to the chassis, and a jig that has been conventionally required is omitted, the manufacturing cost of the jig can be reduced. In addition to the above, the number of steps for operating the jig can be reduced. Moreover, the cap can be accurately positioned on the chassis without the need for the rectangular projection on the upper surface of the chassis which is conventionally required by the projection, and the circuit board is not processed. It can be directly fixed to the upper surface of the chassis. Therefore, the flatness of the surface to which the circuit board is fixed can be improved, and the adhesion of the circuit board to the chassis can be improved.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional plan view schematically showing a chassis, a circuit board and a cap in a circuit board sealing structure according to a first embodiment of the present invention.

FIG. 2 is a side sectional view schematically showing the chassis, the circuit board and the cap in the circuit board sealing structure according to the first embodiment.

FIG. 3 is a partial cross-sectional plan view schematically showing the chassis, the circuit board and the cap in the circuit board sealing structure according to the second embodiment.

FIG. 4 is a side sectional view schematically showing a chassis, a circuit board and a cap in a circuit board sealing structure according to a second embodiment.

FIG. 5 is a perspective view schematically showing a chassis in a conventional circuit board sealing structure.

FIG. 6 is a chassis in a conventional circuit board sealing structure;
FIG. 3 is a perspective view schematically showing a circuit board and a cap.

FIG. 7 is a partial perspective view schematically showing a state in which the chassis is fixed on a jig and the circuit board is fixed on the chassis in the conventional circuit board sealing structure.

FIG. 8 is a partial perspective view schematically showing a state in which the chassis is fixed on a jig and the circuit board is fixed on the chassis in the conventional circuit board sealing structure.

[Explanation of symbols]

 1 electronic component 2, circuit board 40, 50 chassis 4 cap 41, 51, 52 protrusion

Claims (1)

[Scope of utility model registration request] 1. In a circuit board sealing structure in which a circuit board on which an electronic component is mounted and a cap for hermetically sealing the circuit board is fixed to a chassis, positioning of the cap with respect to the chassis and with respect to the chassis A sealing structure for a circuit board, wherein protrusions for positioning the circuit board are formed on the chassis.