JPH0419832Y2 - - Google Patents

Description

[Detailed description of the invention] [Technical field to which the invention pertains] This invention relates to a structure for fixing a printed circuit board in an electrical device incorporating a printed circuit board.

[Prior art and its problems]

In this type of electrical equipment, a printed circuit board is generally attached to the base of the electrical equipment by screws or rivets, and a terminal board for external wiring is also attached to the base by screws or rivets. The conductive part of the board and the terminal board were connected with lead wires. However, for electrical equipment that is mass-produced by assembly-line operations, a slight simplification of the assembly work and a reduction in the number of parts immediately lead to a significant reduction in assembly time and cost. Wiring by wire is not a desirable work, and it is desired to reduce or eliminate it as much as possible. Electrical equipment configured based on this viewpoint will be explained with reference to FIGS. 4 to 7. Figure 4 is a front view, Figure 5 is A-A in Figure 4.
6 is an enlarged view of point B in FIG. 5, and FIG. 7 is a perspective view showing the state of assembly of the terminal board, which is formed on the edge of the surface of the stand 2 of the electrical equipment 1. A groove 5 is formed in the terminal holder 3 so as to communicate with the interior 4 inside the holder 2, and the groove 5 has a holder for a terminal plate 7 for external wiring fitted between the partition walls 6 of the terminal holder 3. The inner wiring connection part 7a is inserted, and in this inserted state, the protrusion 7b formed on the terminal plate 7 engages with the stepped part 5a of the groove 5, and the terminal plate 7 has elasticity in the protruding direction of the protrusion 7b and the stepped part 5a. The conductive portion 8 of the printed circuit board 8 is securely attached to the device base 2 by the engagement of the terminal holder 3, and in this attached state, the tip of the connecting portion 7a is in contact with the back surface of the terminal holder 3.
The conductive part 8a of the printed circuit board 8 and the connecting part 7a of the terminal board 7 are inserted into the hole 8b of the printed circuit board 8.
is integrally soldered 9 while in contact with the back surface of the terminal holder 3. Therefore, in this state of soldering 9, the printed circuit board 8 and the terminal board 7 are securely attached to the device stand 2 with the terminal receiver 3 of the device stand 2 in between, and the conductive parts of the terminal board 7 and the printed circuit board 8 are securely attached to the device stand 2. The wiring with 8a is also connected without using lead wires.

This type of mounting structure has no screws or rivets, and does not use lead wires for wiring, so it is suitable for mass production, but it has the following drawbacks. In other words, a. Because the weight of the various components mounted on the printed circuit board is supported only by the strength of the solder that connects the connection part of the terminal board and the conductive part of the printed base, vibrations and shocks are not applied to the electrical equipment. If this occurs, there is a risk that the soldered portion may crack or break, resulting in poor continuity.

b. When a defective component mounted on a printed circuit board is discovered during testing of a finished product, it is difficult to replace or correct the defective component, and it takes a lot of man-hours.

c. Since the device stand and the printed circuit board are integrated and the printed circuit board is covered by the device stand, the soldering work cannot be done in an automatic soldering tank and must be done manually, resulting in a large number of man-hours for the soldering work.

d In relation to item c) above, when cleaning the flux after soldering, the cleaning residue accumulates in the device stand, so the flux residue cannot be completely washed away, which may cause negative effects such as corrosion. give.

These are the disadvantages.

[Purpose of invention]

This invention eliminates the above-mentioned drawbacks, and provides an electrical device that is easy to solder and assemble, has a reliable connection between an external connection terminal board and a printed circuit board, and has a firm fixation of the printed circuit board. With the goal.

[Key points of the idea]

The key point of this idea is that a terminal block with a fixed terminal board for external connections is mounted on the surface of a printed circuit board, and the legs of the terminal block and the conductive parts of the printed circuit board are connected by soldering on the back side of the printed circuit board. , the printed circuit board is supported by an engaging portion provided in the case, and the case cover, which has an opening through which the terminal block mounted on the case cover is exposed on the front side of the printed circuit board, and the terminal block are connected by fitting. .

[Example of idea]

1 to 3 show an embodiment of this invention. FIG. 1 is a front view of an electrical device 11 which is an embodiment of this invention, and FIG. 2 is a view taken along the line C-C in FIG. 1. The cross-sectional view and FIG. 3 are exploded perspective views of the electrical equipment 11 as described above. Reference numeral 12 denotes a terminal block, in which a plurality of partition walls 12b are provided at equal intervals on the upper surface of a pedestal 12a.
2b has a rear wall 1 having a dovetail convex portion 12e.
A plurality of terminal chambers 12d are formed which are connected by 2c and into which terminal boards described later can be inserted. A terminal plate 13 having an L-shaped cross section is press-fitted into the terminal chamber 12d of the terminal block 12, and a connecting plate 13a of the terminal block 13 is press-fitted.
are in contact with the upper surface of the pedestal 12a, and the leg portions 13b are shaped to hang down along the rear surface of the pedestal 12a. 14 is a printed circuit board, on the surface of which electronic components are arranged;
Terminal lead wires of electronic components pass through the printed circuit board 14 and are connected to the conductive portion 14a on the back side to form an electric circuit. 15 is a case cover, which has an opening 15b in a top wall 15a, a front wall 15c, an intermediate wall 15d, a rear wall 15e, and both side walls 15f.
It is formed of. A dovetail recess 15h (see FIG. 3) is provided in the intermediate wall 15d, and an engaging recess (or engaging hole) 15g is provided in the front wall 15c and rear wall 15e, and a print is printed on the inside of the rear wall 15e. A board holding piece 15i is provided. Reference numeral 16 denotes a case, which has engaging protrusions 16a on its front and rear surfaces, and a printed circuit board support 16b on its inner wall.

Assembly of the above-mentioned parts is carried out in the following order. First, the terminal block 12 is placed on the surface of the printed circuit board 14, and the legs 13b of the terminal block 13 are passed through the printed circuit board 14, and the legs 1 protrude toward the back side.
3b and the conductive part a of the printed circuit board 14 by soldering 17.
Connect by attaching. Next, the printed circuit board 14 on which the terminal block 12 is mounted is inserted into the case 16, and the printed circuit board support 1 provided on the inner wall is inserted into the case 16.
It is supported by the tip end surface of 6b. Next, printed circuit board 1
The case cover 15 is placed over the case 16 with a built-in case 4, but in that case, the dovetail recess 15h of the intermediate wall 15d
Fit the dovetail convex portion 12e of the terminal block 12 into the case cover 15, and push the case cover 15 until the tip of the printed circuit board holding piece 15i provided inside the rear wall 15e of the case cover 15 comes into contact with the surface of the printed circuit board, and then remove the case cover. Front wall 15c Rear wall 15
Cover 15g of the engagement recess (or engagement hole) of e.
6. Engage with the engaging convex portions 16a on the front and rear surfaces to complete the assembly. Note that the engagement uneven portions of the case cover and the cover may be set in the opposite manner.

[Effect of idea]

According to this idea, the terminal block with the terminal board fixed to it is mounted independently on the printed circuit board, and this is inserted into the case, and the case cover is closed from above to hold it in place. The entire printed circuit board carries the weight of the various parts that are connected to it, so even if vibrations or shocks are applied to the electrical equipment, there will be no undue stress on the soldered parts that connect the legs of the terminal board and the conductive parts of the printed circuit board. A good connection can be maintained because no damage is caused. Moreover, since the soldering part is on the back side of the printed circuit board and the surrounding area is open, automatic soldering work can be performed using an automatic soldering tank, which can greatly reduce the number of work steps, and the flux can be removed after soldering. As for removal, the entire printed circuit board can be cleaned and the flux residue can be completely removed, so that the residue does not cause harmful effects such as moisture absorption and corrosion. In addition, since a printed circuit board can be manufactured with a terminal block with a terminal board mounted on it, the characteristics of the electronic circuit can be checked using this printed circuit board alone. The board can be taken out from the case and case cover, and only the defective parts can be easily replaced, and the number of man-hours required for repair can be reduced. Furthermore, the mounting structure of the printed circuit board, case cover, and cover is a fitting method rather than a screw tightening method, so assembly or disassembly is easy, and the printed circuit board can be securely fixed.

[Brief explanation of drawings]

Fig. 1 is a front view of an electrical device incorporating a printed circuit board which is an embodiment of this invention, Fig. 2 is a sectional view taken along the line C-C in Fig. 1, and Fig. 3 is an exploded perspective view of the same electrical device. , Fig. 4 is a front view of an electric device incorporating a printed circuit board with a conventional structure, and Fig. 5 is a view of A- in Fig. 4.
FIG. 6 is an enlarged sectional view taken along arrow B in FIG. 5, and FIG. 7 is a perspective view showing the state of assembly of the terminal board. 11...Electrical equipment, 12...Terminal block, 1
2a...Plinth, 12c...Back wall, 12e...Dovetail convex portion, 13...Terminal board, 13b...Legs, 1
4... Printed circuit board, 14a... Conductive part, 15...
...Case cover, 15a...Top wall, 15b...
Opening, 15c...front wall, 15d...middle wall,
15e...Rear wall, 15f...Side wall, 15g,
16a...Uneven portion, 15h...Dovetail concave portion, 16
...Case, 16b...Printed circuit board support.

Claims (1)

[Scope of utility model registration request] It includes a terminal block to which a terminal board for external wiring is fixed, a printed circuit board on which electronic components are mounted, and a case and a case cover for storing the printed circuit board. The terminal block is mounted on the printed circuit board by soldering to the conductive part of the circuit board, the case has an engaging part on which the printed circuit board is placed inside, and the case cover is mounted on the terminal block mounted on the printed circuit board. What is claimed is: 1. An electrical device incorporating a printed circuit board, characterized in that the circuit board has an opening through which the circuit board is exposed, and is connected to a terminal block by fitting.