JPH0729886U - Board insulation structure - Google Patents

Abstract

(57) [Abstract] [Purpose] To make it possible to easily remove and attach the insulating sheet to the printed circuit board. [Structure] The printed circuit board 12 is fixed to the unit chassis 11 by means of countersunk screws 13 and 13, and a head taper surface 13a of the countersunk screw 13 projects from the substrate surface. A notch 22 is formed in the insulating sheet 21, and the notch 22 is locked to the head tapered surface 13 a of the countersunk screw 13. Locking protrusion 25b formed on the insulating sheet 21
And 25c are inserted and locked under the bottom surface 11a of the unit chassis 11, and the locking protrusion 25a is connected to the cable 26.
It is inserted and locked under a. Since the insulating sheet 21 is locked at a plurality of positions, the entire surface of the sheet does not float up from the printed circuit board 12, and the insulating sheet 21 can be removed by removing the locking portions.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a board insulation structure that insulates between a conductive part of a printed circuit board on which electronic components are mounted and a case, and particularly, the work of attaching the insulation sheet is easy and the insulation sheet is removed during maintenance work. Insulation structure of the substrate that also made it possible.

[0002]

[Prior art]

 FIG. 7 is a perspective view showing the internal unit of the vehicle-mounted disk device taken out of the housing and shown upside down. FIG. 8 is a partial cross-sectional view showing a state where the internal unit is housed in the housing. In FIG. 7, reference numeral 1 is a metal plate unit chassis. The unit chassis 1 is equipped with a rotation drive mechanism for rotating a disc, an optical pickup, and the like. In FIG. 7, a part of the spindle motor M appears on the bottom side. A printed circuit board 2 is installed on the outer peripheral portion of the bottom surface 1a of the unit chassis 1, and is fixed to the unit chassis 1 by screws 3, 3, .... Electronic components such as IC chips, capacitors, resistors, and connectors are mounted on both front and back surfaces of the printed circuit board 2. On the back surface 2a of the printed circuit board 2, various electronic components mounted on the back surface are mounted. Conductive parts such as terminals and soldered parts of the terminals of electronic components mounted on the front surface of the board appear.

As shown in FIG. 8, when the internal unit is housed inside a metal casing 10 with the printed circuit board 2 facing downward, the back surface 2 a of the printed circuit board 2 has a bottom plate 10 a of the chassis 10. They will face each other with a small gap. Therefore, it is necessary to insulate the conductive portion appearing on the back surface 2a of the printed circuit board so as not to contact the bottom plate 10a of the housing 10. For this insulation, as shown in FIG. 8, an insulating sheet 4 is interposed between the printed board 2 and the bottom plate 10a of the housing 10. Conventionally, the insulating sheet 4 is generally attached to the bottom surface 1a of the unit chassis 1. However, as shown in FIG. 7, when the printed circuit board 2 is located on the outer periphery of the bottom surface 1a of the unit chassis 1, as shown in FIG. Makes it impossible to fix the insulating sheet 4 to the bottom surface 1a. Therefore, in the case of the structure of FIG. 7, it is necessary to directly fix the insulating sheet 4 to the printed board 2.

[0004]

[Problems to be solved by the device]

 In the above, when the insulating sheet 4 is attached to the printed board 2 by the screws 3, 3, ... Or other screws, the screwing work must be performed at a plurality of places, and the mounting work is complicated, and At this time, a torsional stress acts on the screw insertion hole of the insulating sheet 4 to cause a problem that the insulating sheet 4 is bent. Furthermore, when the insulating sheet 4 is removed for maintenance work, the screw must be loosened, and the work is complicated. Further, if the insulating sheet 4 is adhered to the printed circuit board 2 with an adhesive member 5 such as a double-sided adhesive tape, it is difficult to align the insulating sheet 4 with the printed circuit board 2, and the insulating sheet 4 is not securely fixed and falls off. There is a risk.

The present invention has been made to solve the above problems, and an object of the present invention is to provide an insulating structure for a substrate, which allows an insulating sheet to be accurately and easily attached to a printed substrate without misalignment. It is intended.

[0006]

[Means for Solving the Problems]

 The present invention is an insulating structure of a board in which a printed circuit board on which electronic components are mounted is covered with an insulating sheet, the printed circuit board being fixed with a countersunk screw, and the head of the screw is further attached to the surface of the printed circuit board. The insulating sheet is locked to the taper surface of the screw.

Further, in the above description, when the fixed object is located in a position aligned with the printed circuit board, the edge portion of the insulating sheet may be locked to the lower surface of the fixed object.

[0008]

According to the first means, the insulating sheet is mounted on the surface of the printed circuit board by locking the notch formed in the insulating sheet with the tapered surface of the head of the flat head screw. When removing the insulating sheet, it suffices to release the lock on the countersunk screw. For example, when the cutout portion formed in the insulating sheet is locked to the countersunk screw, the insulating sheet is accurately positioned and attached to the printed circuit board. Since the flat head screws are used for mounting the printed circuit board, the number of screws is minimal.

In the second means, the edge portion of the insulating sheet is locked to the lower surface of the fixing portion. Therefore, for example, the minimum number of locking points for the countersunk screw is one or two, and the other parts are locked on the lower surface of the fixing part, so that the insulating sheet is first locked by the locking with the countersunk screw. It is possible to prevent the edges of the insulating sheet from being lifted from the printed circuit board after being positioned, and it is possible to reliably install the insulating sheet almost entirely over the printed circuit board by a simple mounting operation.

[0010]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. 1 is a perspective view showing an embodiment of an insulating structure of a substrate of the present invention, in which an internal unit of an in-vehicle disc device is turned upside down, FIG. 2 is a perspective view showing an insulating sheet, and FIG. 3 is FIG. 4 is a partial perspective view showing a locking portion between the insulating sheet and the countersunk screw, FIG. 4 is a sectional view showing a locking portion in FIG. 3, and FIGS. 5 and 6 are partial perspective views showing locking portions at other portions of the insulating sheet. It is a figure. Similar to the conventional example shown in FIG. 7 and FIG. 8, the internal unit shown in FIG. 1 is installed inside the metal casing 10 with the printed board 12 facing downward, and as shown in FIG. The back surface 12a of the housing 12 faces the bottom plate 10a of the housing 10 with a minute gap.

In this embodiment, a rectangular window is formed at the center of the bottom surface 11a of the unit chassis 11, and the bottom portion of the spindle motor M for driving the disk rotation appears in this window. A printed circuit board 12 is attached to the outer periphery of the bottom surface 11a of the unit chassis 11. Two parts of the printed board 12 are fixed to the unit chassis 11 with countersunk screws 13 and 13. As shown in FIG. 4, a screw insertion hole 12b is formed in the printed circuit board 12, and the shaft portion 13b of the countersunk screw 13 is inserted in the screw insertion hole 12b and formed in a bent piece of the unit chassis 11 or the like. It is screwed into the female screw hole 11b. The screw insertion hole 12b is a hole having a diameter slightly larger than the outer shape of the shaft portion 13b of the countersunk screw 13, so that the head taper surface 13a of the countersunk screw 13 projects from the back surface 12a of the print substrate 12. become. Further, other parts of the printed board 12 may be fixed by screws other than the countersunk screw, if necessary.

Cable connectors 14 a, 14 b, 14 c, 14 d, a resistor 15, a capacitor 16 and the like are mounted on the back surface 12 a of the substrate 12. A large number of discrete components are mounted on the front surface of the printed board 12, the terminals of which are projected to the back surface 12a side of the printed board 12, and the terminals and the conductive patterns are soldered on the back surface. Most of the back surface 12a of the substrate 12 is covered with an insulating sheet 21. The insulating sheet 21 is a flexible transparent resin plate such as vinyl chloride. Notches 22 are formed in the insulating sheet 21 at two corresponding positions of the countersunk screws 13, 13. As shown in an enlarged view in FIG. 3, the cutout portion 22 is formed to have a width dimension A1, and the open end 22a thereof is narrowed to the width dimension A0. The width A0 of the open end 22a is smaller than the diameter B0 of the smallest diameter portion of the head taper surface 13a appearing on the printed circuit board 12 shown in FIG. The width dimension A1 is larger than the dimension B0 and smaller than the diameter dimension B1 of the maximum diameter portion of the tapered surface 13a.

As shown in FIG. 2, the insulating sheet 21 is provided with other notches 23a, 23b, 23c and holes 24a, 24b, 24c, 24d, 24f. These are for checking and measuring the clearance holes surrounding the cable connectors 14a to 14d, the resistor 15, the capacitor 16 and the like, or the terminal portion. Of course, it is not always necessary to provide these notches and holes. Further, locking protrusions 25a, 25b, 25c having a size protruding from the edge of the substrate 12 in a plane are formed at three positions of the edge of the insulating sheet 21.

Next, the work of attaching the insulating sheet to the substrate will be described. Each member is attached to the unit chassis 11, and the printed circuit board 12 on which electronic components are mounted is fixed by countersunk screws 13 and 13. Then, the cables 26a, 26b, 26c extending from the respective electronic mechanism portions in the unit chassis 11 are connected to, for example, the cable connectors 14a, 14c, 14d. After that, the insulating sheet 21 is placed on the back surface 12 a of the printed board 12. In this operation, first, the open end 22a of the cutout portion 22 is widened, and the cutout portion 22 is locked to the head tapered surface 13a of the countersunk screw 13 protruding from the printed circuit board 12. In the embodiment shown in FIG. 1, the notches 22 formed at two positions of the insulating sheet 21 are respectively locked to the head tapered surface 13a. The insulating sheet 21 is positioned with respect to the printed circuit board 12 by the engagement of the cutout portion 22 and the head tapered surface 13a.

However, if only the two cutouts 22, 22 are locked, the other edge of the insulating sheet 21 is lifted from the printed board 12. Therefore, in the embodiment of FIG. 1, a recess 11c is formed on the bottom surface 11a of the unit chassis 11, and the locking projection 25b of the insulating sheet 21 is inserted into this recess 11c and locked on the lower surface of the bottom surface 11a. (See FIG. 5). Since the recessed portion 11c can restrain the locking projection 25b from both the left and right sides, the locking portion prevents the insulating sheet 21 from being displaced in a planar manner and positions the insulating sheet 21. Similarly, the locking projection 25c of the insulating sheet 21 is inserted into the lower surface of the step portion 11d at the right end of the unit chassis 11 in FIG. Further, as shown in FIG. 6, the L-shaped locking protrusion 25a formed on the insulating sheet 21 is inserted into the lower side of the cable 26a and locked to the cable 26a. In this way, the insulating sheet 21 is locked at a plurality of positions, and almost the entire surface of the insulating sheet 21 does not float above the back surface of the printed circuit board 12. Further, the insulating sheet 21 can be easily removed by releasing the locks at the above-mentioned locations, and the insulating sheet 21 can be easily reattached.

In the illustrated embodiment, the insulating sheet 21 is locked to the countersunk screw 13 at two positions, but may be locked to the countersunk screw 13 at only one position. In this case, for example, by restraining the locking projection 25b by the recess 11c, it is possible to prevent the insulation sheet 21 from being displaced by the single screw 13 and the single recess 11c for the positioning. It is possible. The locking projection may be locked to a fixed part other than the unit chassis 11 or an electronic component other than the cable 26a. Further, the insulating structure of the present invention can be implemented in other electronic devices mounted on a vehicle and further other electronic devices mounted on a vehicle.

[0017]

[Effect of device]

 In the device according to the first aspect, the insulating sheet can be attached easily and detachably. Also, the number of screws used is minimized because the insulation sheet is locked using the countersunk screws that attach the printed circuit board.

According to the second aspect of the present invention, it is possible to prevent the edge portion of the insulating sheet other than the locking portion from being lifted up from the printed board by the countersunk screw.

[Brief description of drawings]

FIG. 1 is a perspective view showing an internal unit of an in-vehicle disk device as an embodiment of the present invention with a printed circuit board facing upward;

FIG. 2 is a perspective view showing an insulating sheet,

FIG. 3 is a perspective view showing a locking portion between an insulating sheet and a flat screw,

FIG. 4 is a sectional view of FIG.

FIG. 5 is a perspective view showing a locking portion between an insulating sheet and a unit chassis,

FIG. 6 is a perspective view showing a locking portion between an insulating sheet and a cable,

FIG. 7 is a perspective view showing an internal unit of a vehicle-mounted disc device showing a conventional example;

FIG. 8 is a partial cross-sectional view showing a state where the internal unit is housed in a housing,

[Explanation of symbols]

 10 Housing 10a Bottom Plate 11 Unit Chassis 11a Bottom 11c Recess 12 Substrate 13 Countersunk Screw 13a Head Tapered Surface 14a to 14d Cable Connector 15 Resistor 16 Capacitor 21 Insulation Sheet 22 Cutout 22a Open End 25a to 25c Locking Protrusion 26a Cable

Claims (2)

[Scope of utility model registration request] 1. An insulating structure of a board, in which a printed board on which an electronic component is mounted is covered with an insulating sheet,
The printed circuit board is fixed by a counter screw, the head of the counter screw projects from the surface of the printed circuit board, and the insulating sheet is locked to the tapered surface of the counter screw. Insulation structure. 2. The insulating structure for a board according to claim 1, wherein the fixed object is located at a position aligned with the printed circuit board, and an edge portion of the insulating sheet is locked to a lower surface of the fixed object.