JPH08153450A - Surface mount type magnetic proximity switch - Google Patents

Abstract

PURPOSE: To realize a stable mount when a magnetic proximity switch is surface-mounted on a printed wiring board, eliminate the slippage, and also eliminate the influence on the sensitivity characteristic of the switch. CONSTITUTION: This switch has a reed switch 1 and a resin mold case 2 for protecting it, and the case has a slit 2c, an insert guide 2a and a groove 2b. The reed switch 1 is housed in the slit 2c of the resin mold case 2, and its lead terminal 1a is pressed and fixed into the groove 2b. The lead terminal 1a of the reed switch 1 is bent in parallel to a printed wiring board on the bottom surface 2d of the resin mold case 2, and pressed and fixed into the resin mold case 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface mount type magnetic proximity switch, and more particularly to a surface mount type magnetic proximity switch for surface mounting on a printed wiring board.

[0002]

2. Description of the Related Art Heretofore, as an example of a surface mount type reed switch, there has been processed a lead terminal as described in Japanese Utility Model Laid-Open No. 2-148515.

FIGS. 8A to 8C are a plan view and a front view of a reed switch and a cross-sectional view of mounting on a printed wiring board for explaining such a conventional example. FIG.
As shown in (a) to (c), in this surface mount reed switch, the lead terminals at both ends of the insulating container 5 have a predetermined width W3.
The rolled lead terminal 6 is rolled to form a rolled lead terminal 6, and the rolled lead terminal 6 is bent near the insulating container 5 to form a leg portion 6a and a mounting portion 6b. As described above, the reed switch having the lead terminal 6 formed thereon is mounted on the printed wiring board 4, but the mounting portion 6 is used for mounting.
b is fixed to the conductor pattern 4a on the wiring board 4 via the solder 3. Since the insulating container 5 does not contact the printed wiring board 4 in such a reed switch, surface mounting can be performed without making holes in the printed wiring board 4.

Regarding the mounting of the reed switch on the printed wiring board, as described in Japanese Utility Model Laid-Open No. 3-15446, a reed switch mounting auxiliary tool is also used.

FIG. 9 is a mounting cross-sectional view of a reed switch showing another conventional example. As shown in FIG. 9, in this example, the reed switch 1 is mounted on the printed wiring board 4 with the solder 3 or the like via the mounting aid main body 7. In this example, the recess 7a provided on the upper surface of the mounting aid main body 7 and the auxiliary tool body 7
7c provided with a hole 7b through which the lead wire 1a of the reed switch 1 is formed, which is provided on the side surface of the auxiliary tool main body 7
4b provided on the bottom surface of the printed wiring board 4 and on the printed wiring board 4
And a convex portion 7d that fits in. As a result, the lead terminals 1a of the reed switch 1 can be surface-mounted without protruding to the back surface of the printed wiring board 4.

Similarly, regarding the mounting of the reed switch on the printed wiring board, there is an example in which a reed switch holding device is used as described in Japanese Utility Model Application Laid-Open No. 56-22744.

FIGS. 10 (a) and 10 (b) are a cross-sectional view of a reed switch holding device and an enlarged view of its essential part for explaining another conventional example. As shown in FIG. 10 (a), in this example, two elastic holders 9 made of conductive rubber are mounted on an insulating substrate 8 at intervals, and both elastic holders 9 are attached to both sides of the reed switch 1. The lead terminal 1a is attached. In this example, the lead wire 10 is connected to the rivet 11 that fixes the holder 9. In addition, 1b is a glass tube.

Further, as shown in FIG. 10 (b), the elastic holder 9 is provided with a notch 9b in the standing piece 9a, and the lead terminal 1a of the reed switch 1 is inserted into the notch 9b and held. With such a structure, the operating sound from the reed switch 1 is not transmitted, and external force due to vibration, deformation of the substrate, thermal expansion, etc. does not reach the reed switch 1.

[0009]

The above-mentioned conventional surface mount type reed switch, especially the reed switch shown in FIGS. 8A to 8C, is surface mountable by rolling the lead terminals at both ends in the vicinity of the insulating container. It is used as a rolled lead terminal. However, there is a drawback in that it is difficult in mass production to perform rolling while maintaining the sealing property of an insulating container made of a glass tube or the like, crack resistance, or the sensitivity characteristic of the reed switch. When a lead terminal having a diameter of 0.3 to 0.6 mm is rolled, the rolling width (w3) is generally about 2 times the diameter.
Double rolling (approximately 0.6 to 1.2 mm) is possible, but with this rolling width, the reed switch tends to tilt or fall during surface mounting on a printed wiring board, which is also difficult for mass production. There is a problem. Further, the surface mount reed switch described above has a drawback that the glass tube is not protected.

Next, the surface mount type reed switch described with reference to FIG. 9 is an example in which a reed switch mounting aid is used in order to supplement mountability on a printed wiring board. It is a structure in which a switch is placed and the lead terminal is inserted through the hole of the protruding piece. In such a structure, the lead terminal is not fixed to the mounting aid body,
There are drawbacks such that the reed switch is displaced during mounting on the printed wiring board, and the sensitivity characteristics of the reed switch are easily affected. Further, in the structure in which the reed switch is placed in the concave portion of the mounting aid main body, there is a problem that the glass tube is not protected in the Y direction (the upper direction of the glass tube) which is most likely to contact the glass tube during mounting.

Similarly, the reed switch holding device described in FIGS. 10 (a) and 10 (b) has a structure in which an elastic holder made of conductive rubber is used and the lead terminal is held in the notch of the standing piece. With such a structure, it is difficult to fit and hold the lead terminal due to the nature of rubber, and the position of the reed switch is easily displaced, which has a drawback that the sensitivity characteristic of the reed switch is affected. Further, this reed switch also has a problem that the glass tube is not protected, like the two conventional examples described above.

The object of the present invention is suitable for the above-mentioned mass productivity,
An object of the present invention is to provide a surface mount type magnetic proximity switch capable of protecting glass without affecting the positional displacement of the reed switch and the sensitivity characteristics.

[0013]

A surface mount type magnetic proximity switch according to the present invention comprises a reed switch having lead terminals at both ends of a sealed glass tube, a slit for protecting the reed switch and the reed terminal. And a resin mold case with a groove formed,
The lead terminal of the reed switch is press-fitted and fixed in the groove.

Further, the resin mold case of the surface mount type magnetic proximity switch has a groove formed on a bottom surface which is in contact with a printed wiring board to be mounted, and the lead terminal of the reed switch is bent in parallel with the printed wiring board. ,
It is characterized by being press-fitted and fixed in the groove provided on the bottom surface of the case.

[0015]

Next, the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view of a surface mount type magnetic proximity switch showing a first embodiment of the present invention, and FIG. 2 is an exploded perspective view of the switch shown in FIG. Referring to FIGS. 1 and 2, the present embodiment comprises a reed switch 1 and a resin molded case 2, the reed switch 1 includes lead terminals 1a at both ends of a sealed glass tube 1b, and the reed switch 1 The resin mold case 2 that is housed to protect the above-described parts has a slit 2c, a guide 2a into which the terminal 1a is inserted, and a groove 2b. Further, a groove different from the groove 2b is formed on the bottom surface 2d of the case 2 for press-fitting and fixing the terminal 1a. As shown in FIG. 2, when mounting the reed switch 1, the reed switch 1 is positioned in the Y direction by the insertion guide 2a of the resin mold case 2, and then positioned in the X direction by the groove 2b and the resin mold case 2 is mounted. Is fixed to. At this time, the slit 2c of the case 2 accommodating the reed switch 1 is formed so that the glass tube 1b of the switch 1 does not come into contact with the surrounding resin mold.

3 (a) and 3 (b) are an enlarged sectional view taken along line AA and an enlarged sectional view taken along line BB in FIG. 1, respectively. As shown in FIG. 3A, the insertion guide 2a into which the lead terminal 1a is inserted forms an insertion opening 2e and a positioning portion 2f, and the tilted insertion opening 2e serves as a guide to position the reed switch terminal 2f. Insert 1a. The positioning portion 2f is wider than the outer diameter of the reed switch terminal 1a in the width w1 (for example, the outer diameter of the reed terminal 1a is 0.5 mm, the width of the positioning portion 2f is 0.7 m).
m) and does not contact the surrounding resin mold part.

On the other hand, as shown in FIG. 3 (b), the groove 2b forms a set portion 2g, a passage portion 2h and a fixed portion 2i. Here, the lead terminal 1a set in the setting portion 2g has a passage portion 2h whose width is set to be narrower than the outer diameter of the lead terminal 1a (for example, the outer diameter of the lead terminal 1a is 0. Passing section 2h for 0.5 mm
The width of 0.4 mm) of the fixed part 2i
It is press-fitted and fixed in. At this time, the width w2 of the passing portion 2h is restored to almost the original width by the restoring force of the resin after the lead terminal 1a has passed, and the lead terminal 1a does not fall off from the resin molded case 2.

FIG. 4 is a sectional view of the switch shown in FIG. 1 mounted on a printed wiring board. As shown in FIG. 4, here, on the bottom surface 2d of the resin molded case 2 accommodating the reed switch 1, the lead terminal 1a is bent in parallel with the printed wiring board 4, and the same as the groove 2b described in FIG. 3B. Pressed and fixed. Thereafter, the lead terminal 1a is soldered to the pattern or the like on the wiring board 4 by the solder 3.

FIG. 5 is a perspective view of a resin mold case for explaining the second embodiment of the present invention. As shown in FIG. 5, the present embodiment shows only the resin mold case 2, and the reed switch 1 is omitted because it is the same as the first embodiment described above. In this embodiment, the resin mold case 2 has a slit 2c for accommodating the reed switch.
The rib 2j is characterized in that it is erected on the back surface thereof, and the insertion guide 2a and the groove 2b of the lead terminal are the same as in the case 2 of FIG. By providing such rib portions 2j, the strength of the case 2 itself in the Y direction can be reinforced. The rib portion 2j is also formed so as not to contact the glass tube of the switch.

FIG. 6 is a perspective view of a surface mount type magnetic proximity switch showing a third embodiment of the present invention. As shown in FIG. 6, in this embodiment, the lead terminals 1a are led out from the bottom surface of the resin mold case 2 instead of being led out to the outside. Therefore, in this embodiment, a groove facing inward is formed on the bottom surface of the case 2. In this way, by bending the lead terminals 1a inside the resin molded case 2, it is possible to save the mounting area.

FIGS. 7A and 7B are a perspective view and a sectional view taken along the line D-D of a surface mount type magnetic proximity switch showing a fourth embodiment of the present invention. 7 (a), (b)
In this embodiment, the groove formed on the bottom surface of the resin mold case 2 is formed so as to be perpendicular to the axial direction of the reed switch and opposite to each other. It is bent in the opposite direction. In this way, by bending the lead terminal 1a in a direction perpendicular to the glass tube 1b and in the opposite direction, when the proximity switch itself is mounted on the printed wiring board, it is stable regardless of the force applied from any direction. Can be implemented.

[0023]

As described above, in the surface mount type magnetic proximity switch of the present invention, the lead terminal is rolled by inserting the reed switch into the resin mold case having the slit, the insertion guide and the groove. Since it can be stably mounted on a printed wiring board, there is an effect that a structure suitable for mass productivity can be obtained. Further, according to the present invention, the position of the lead terminal is determined by the insertion guide and the groove formed in the resin mold case, and moreover, the lead terminal is press-fitted and fixed in the groove, so that the reed switch is not displaced during mounting, and the lead is prevented from being displaced. This has the effect of not affecting the sensitivity characteristics of the switch. Further, the present invention has an effect that the glass tube of the reed switch can be protected because the glass mold of the reed switch has the resin mold case in the upper surface direction which is most easily contacted during mounting.

[Brief description of drawings]

FIG. 1 is a perspective view of a surface mount type magnetic proximity switch showing a first embodiment of the present invention.

FIG. 2 is an exploded perspective view of the switch shown in FIG.

3 is an enlarged cross-sectional view taken along the line AA and the line BB in FIG.

FIG. 4 is a sectional view of mounting the switch shown in FIG. 1 on a printed wiring board.

FIG. 5 is a perspective view of a resin mold case for explaining a second embodiment of the present invention.

FIG. 6 is a perspective view of a surface mount type magnetic proximity switch showing a third embodiment of the present invention.

FIG. 7 is a diagram showing a perspective view of a surface mount type magnetic proximity switch showing a fourth embodiment of the present invention and a cross section taken along line D-D thereof.

FIG. 8 is a view showing a plane and a front surface of a reed switch and a mounting cross section on a printed wiring board for explaining an example of the related art.

FIG. 9 is a mounting cross-sectional view of a reed switch showing another conventional example.

FIG. 10 is an enlarged view showing a cross section of a reed switch holding device and a main part thereof for explaining another conventional example.

[Explanation of symbols]

 1 Reed Switch 1a Reed Terminal 1b Glass Tube 2 Resin Molded Case 2a Insertion Guide 2b Groove 2c Slit 2d Bottom 2e Insertion Port 2f Positioning Part 2g Set Part 2h Passing Part 2i Fixed Part 2j Rib 3 Solder 4 Printed Wiring Board

Claims (3)

[Claims] 1. A reed switch having lead terminals on both ends of a sealed glass tube, a slit for protecting the reed switch, a resin mold case having an insertion guide for inserting the lead terminal and a groove formed therein. A surface mount type magnetic proximity switch, wherein the lead terminal of the reed switch is press-fitted and fixed in the groove. 2. The resin-molded case has a groove formed on a bottom surface in contact with a printed wiring board to be mounted, the lead terminal of the reed switch is bent in parallel with the printed wiring board, and is provided on the bottom surface of the case. The surface mount type magnetic proximity switch according to claim 1, wherein the surface mount type magnetic proximity switch is press-fitted and fixed in the groove. 3. The surface mount type magnetic proximity switch according to claim 1, wherein the resin mold case has a rib formed on the back surface of the slit.