JPH0945193A - Electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the idling of a coil case or the like in a cylindrical case by providing grooves in the axial direction connected to a thin section on the cylindrical case, and filling a resin in the void of the cylindrical case. SOLUTION: A coil case 7 is stored in a base metal 8. The base metal 8 is a cylindrical metal case formed with thread grooves on the outer periphery, a clamp section 9 is fitted on the back face, and the clamp section 9 is provided with an opening 9a for filling a resin into the cylindrical case. The base metal 8 has a thin section 8a made slightly thin in thickness at the tip section for storing the coil case 7, and two grooves 8b, 8c are provided at symmetrical positions in the axial direction of the thin section 8a into which the coil case 7 is inserted. Since the grooves 8b, 8c are provided in succession to the thin section 8a, a machining tool can be inserted from the opening section of the base metal 8, machining is facilitated, a resin is filled in the grooves 8b, 8c when it is filled in the cylindrical case, and the idling of the coil case 7 can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic device such as a proximity sensor, and more particularly to a cylindrical electronic device in which a case is filled with resin.

[0002]

2. Description of the Related Art FIG. 7 is a sectional view showing an example of a conventional high frequency oscillation type proximity sensor. In the conventional proximity sensor 101, an annular groove is provided in the core 102, and the coil 104 held by the coil spool 103 is embedded in the groove. The core 102 is held on the front surface of the resin coil case 105 as shown in the drawing, and these are housed in the base metal fitting 106. An electronic circuit unit 107 includes an oscillation circuit including the coil 104 and a signal processing unit that detects a decrease in the amplitude of the oscillation, and is mounted on the printed board 108. After the coil 104 is connected to the printed board 108, the coil case 105 is provided to stabilize the performance.
The core 102 is filled with the primary filling resin 109. Further, in order to improve the environment resistance, the case of the proximity sensor is filled with the epoxy resin 110. At the time of filling the epoxy resin 110, the resin heated to a high temperature is filled using, for example, a syringe. And the clamp portion 111
The cord 112 is held by and constitutes a proximity sensor. Further, the base metal fitting 106 is provided with an opening 114 for guiding the light of the display 113 to the outside.
Up to 4 is filled with resin. By filling the epoxy resin 110 up to the opening 114, rotation of the proximity sensor is prevented after the resin is filled. A sealing tape 115 is attached to the opening from the outer surface of the case to prevent the resin from flowing out when the resin is filled.

[0003]

In such a conventional proximity sensor, the opening 114 for the operation indicating lamp is also filled with the filling resin, so that the rotation can be prevented. However, it is necessary to provide an opening on the side wall of the base metal fitting or to attach a sealing tape to seal the resin, which has a drawback of increasing the number of assembling steps.

The present invention has been made in view of such a conventional problem, and prevents idle rotation in a case of an electronic device without providing a display element on the outer peripheral surface of the cylindrical electronic device. The purpose is to be able to.

[0005]

The invention of claim 1 of the present application is a cylindrical case having a bottomed cylindrical case having a coil inside, and a thin walled portion for accommodating the coil case at the tip. An electronic device having a case is characterized in that the cylindrical case has an axial groove connected to the thin wall portion, and a void is filled with a filling resin. Claim 2 of the present application
In the invention, at least two grooves of the cylindrical case are provided.

For this reason, when the case is filled with resin in this electronic device, an axial groove is provided following the thin-walled portion for housing the coil case, and the groove is also filled with the resin. The rotation of the filling resin and the printed circuit board can be prevented.

[0007]

1 is a vertical sectional view of a proximity sensor according to an embodiment of the present invention, FIG. 2 is a horizontal sectional view thereof, and FIG. 3 is an assembly configuration diagram thereof. As shown in these figures,
In the proximity sensor 1 according to this embodiment, an annular groove is formed in the core 2, and the coil 4 wound around the coil spool 3 has the core 2.
It is stored in the annular groove of. An elongated printed board 5 is connected to the back surface of the core 2 as shown in the drawing, and a shield film 6 covering the oscillation circuit portion of the printed board 5 is provided. In FIG. 2, the shield film 6 is omitted. And the core 2 is the coil case 7
Is stored in. The coil case 7 is a resin-made bottomed cylindrical member, and a protrusion, which will be described later, is formed on the inner peripheral portion of the coil case 7. The coil case 7 is housed in the base metal fitting 8. The base metal fitting 8 is a metal cylindrical case having a thread groove formed on the outer periphery thereof, and a clamp portion 9 is attached to the back surface thereof. The clamp portion 9 is a transparent or semi-transparent resin member, and holds the cord 10. The clamp portion 9 has an opening 9a for filling the case with resin.
Is provided.

Next, the coil case 7 will be described in more detail. The coil case 7 is a side view in FIG. 4A, and FIG.
FIG. 5 is a vertical sectional view thereof, and FIG. 5 is a sectional view taken along line AA.
It is a cylindrical member having a U-shaped cross section with its front surface covered. Then, as shown in the drawing, first linear protrusions 21a to 21d for preventing resin leakage are provided on the inner peripheral surface accommodated in the base metal fitting 8.
Is provided. Linear protrusions 21a to 21 for preventing resin leakage
Reference numeral d is a linear projection that is intermittently formed at four locations and is formed so as to substantially cover the circumference of the coil case 7. Further, second linear projections 22a to 22d for preventing resin leakage having a shorter length than the center of the cutout portions of the linear projections 21a to 21d are provided inside thereof. The notched portions of the first and second linear protrusions 21a to 21d and 22a to 22d serve as air outflow grooves. Furthermore, the linear protrusion 21a
Projections 23a to 23d having an arcuate cross-section and having the same height as the cutouts are provided in the middle positions of the cutouts. Further, projections 24a to 24d having an arcuate cross-section and having the same height as the linear projections 22a to 22d are provided at intermediate positions. These arc-shaped projections 22a to 22d, 24
When the coil case 7 is press-fitted into the base metal fitting 8, a to 24d are coaxially held so that the coil case 7 does not tilt so that the air outflow grooves are not uneven. The opening end of the coil case 7 is shown in FIG.
As shown in (a) and (b), the linear protrusions 22a to 22d
Only the portion not corresponding to has the notch portions 25a to 25d which are notched inward as shown in the drawing. The cutouts 25a to 25d connect the coil case 7 to the base metal 8
It is provided to secure an outflow path for air when stored inside. Here, an intermediate portion between the linear protrusions 21a to 21d and the linear protrusions 22a to 22d is a groove 26 for resin accumulation. As shown in FIG. 4A, the linear protrusions 21a to 21d and 22a to 22d are provided with an inclination on the inner side,
Further, the inner thickness of the linear protrusions 22a to 22d is configured to be thicker.

As shown in FIG. 1 and FIG. 6A, the base metal fitting 8 has a thin wall portion 8a for accommodating the coil case 7 in which the wall thickness of the tip of the base metal fitting is slightly reduced. . Then, the thin thick portion 8a into which the coil case 7 is inserted
And the two grooves 8 at the positions symmetrical to the axial direction.
b and 8c are provided. 8 following thin-walled portion 8a
By providing b and 8c, a processing tool can be inserted from the opening of the base metal fitting 8, and thus the processing becomes easy. The grooves 8b and 8c are for preventing idling by filling the groove with the resin when the case is filled with the resin.

Next, the manufacturing process of the proximity sensor according to this embodiment will be described. The coil 4 wound around the coil spool 3 is stored in the annular groove of the core 2 in advance. Then, the leads 4a and 4b at both ends of the coil 4 are connected to the printed board 5 and the shield film 6 is wound around the printed board 5. Next, in this state, the core 2 is housed in the coil case 7, and is preliminarily filled with the epoxy-based coil portion sealing resin 51 in advance in order to stabilize the coil characteristics. Next, the cord 10 is passed through the base metal fitting 8 and the clamp portion 9, and the terminal of the cord 10 is connected to a predetermined portion of the printed board 5. Next, the coil case 7 is housed in the base metal fitting 8. Then, the clamp portion 9 is housed in the inner wall of the base metal fitting 8 to form a proximity sensor. Then, the proximity sensor is housed in a mold to be in a vacuum state. In this way, the inside of the proximity sensor has the linear protrusions 22a to 22d and 21a of the coil case 7.
Air is sucked to the outside through the air outflow groove in the gap of ~ 21d, and the pressure inside the proximity sensor also drops. In this state, the filling resin having a high temperature is injected from the opening 9a of the clamp portion 9 at a low pressure, for example, 5 to 20 atmospheres. In this way, the filling resin hits the printed circuit board 5, and then is filled in the case,
In addition, the whole case will be covered. At this time, the filling resin also enters the grooves 8b and 8c of the base metal fitting 8. By selecting the mold temperature at an appropriate value, the proximity sensor can be constructed in a short time. At this time, the air flows between the linear projections 21a to 21d and 22a to 22d in the direction of arrow C in FIG. 4, but the resin injected at a low pressure hits the linear projections 21a to 21d, and the resin pool groove 2
Since the filler is accumulated in the coil case 6, the filler can be retained in the base metal member 8 without leaking out of the coil case 7. When the proximity sensor is configured in this manner, even if the filling resin contracts, the filling resin remains in the grooves 8b and 8c, so that the printed circuit board 5 and the filling resin do not rotate in the case.

In this embodiment, two grooves are formed on the base metal fitting, but it is sufficient to form at least one groove on the base metal fitting. However, as shown in FIG. 6B, even if the thin-walled portion 8a of the base metal fitting 8 is eccentric, if at least two grooves are provided at symmetrical positions about the central axis, at least one of them is provided. A sufficient step can be secured. Therefore, it is preferable to provide the grooves at at least two places.

Although the present embodiment describes the proximity sensor, the present invention is applicable to various electronic devices, such as a data carrier of an ID system, which has a coil case in the case and whose gap is filled with resin. It is possible to apply.

[0013]

As described above in detail, according to the present invention, since the groove is formed in the base metal fitting continuously with the thin wall thickness portion into which the coil case is inserted, when the resin is filled, the groove is also formed in this groove. The resin will be filled. Therefore, even when the filled resin is aggregated and contracts, the printed circuit board and the coil case in the case do not rotate in the base metal fitting, and the rotation can be prevented in advance.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a proximity sensor according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a proximity sensor according to an embodiment of the present invention.

FIG. 3 is an assembly configuration diagram of a proximity sensor according to an embodiment of the present invention.

4A is a side view of a coil case of the proximity sensor according to the present embodiment, and FIG. 4B is a vertical sectional view thereof.

FIG. 5 is a sectional view taken along line AA of the coil case according to the present embodiment.

6A and 6B are front views of a base metal fitting.

FIG. 7 is a sectional view showing an example of a conventional proximity sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Proximity sensor 2 Core 3 Coil spool 4 Coil 5 Printed circuit board 6 Shield film 7 Coil case 8 Base metal fitting 8a Thin-walled part 8b, 8c Groove 9 Clamp part 10 Code 21a-21d First linear protrusion 22a-22d Second Linear protrusions 23a to 23d, 24a to 24d Protrusions 25a to 25d Cutout portion 26 Resin leak prevention groove

Claims (2)

[Claims] 1. An electronic device comprising: a coil case having a bottomed cylindrical shape and having a coil inside; and a cylindrical case having a thin wall portion for accommodating the coil case at a tip end portion thereof. An electronic device having an axial groove connected to the thin portion and filling a void in the cylindrical case with a filling resin. 2. The electronic device according to claim 1, wherein at least two grooves are provided in the cylindrical case.