JP3279187B2 - Proximity sensor and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a proximity sensor having a characteristic structure when a resin is filled, and a method for manufacturing the same.

[0002]

2. Description of the Related Art FIG . 20 is a sectional view showing an example of a conventional high frequency oscillation type proximity sensor. In a conventional proximity sensor 201, an annular groove is provided in a core 202, and a coil 204 held by a coil spool 203 is embedded in this groove. The core 202 is held on the front surface of a coil case 205 made of resin as shown in the figure, and these are housed in a metal case 206. An electronic circuit unit 207 includes an oscillation circuit including the coil 204 and a signal processing unit that detects a decrease in the amplitude of the oscillation, and is mounted on the printed circuit board 208. Then, the coil 204 is mounted on the printed circuit board 208.
After connecting the coil case 20 to stabilize the performance
5 is filled with the primary filling resin 209 on the core 202 side.
In order to improve the environmental resistance, the case of the proximity sensor is filled with the epoxy resin 210. When filling the epoxy resin 210, for example, a high temperature resin is filled using a syringe or the like. And the clamp part 21
1 constitutes a proximity sensor by holding the code 212. In some cases, the proximity sensor is formed by integrally molding a thermoplastic resin without casting and sealing the resin in the case.

[0003]

However, such a conventional electronic device as a proximity sensor or the like requires preparations such as stirring of the resin to be injected, and injects the filling resin into the case using a syringe or the like. However, since the resin shrinks when cured, it is necessary to add resin to the contracted portion again. Therefore, there are drawbacks that the number of working steps is large and the curing time is as long as about 1 hour. Further, when integrally molded using a thermoplastic resin, there is a drawback that the injection pressure during molding is high and the built-in components may be damaged.

The present invention has been made in view of such conventional problems, and a proximity sensor and a proximity sensor which can solve such problems by performing low pressure injection molding using a thermosetting resin. It is an object to provide a method for manufacturing a sensor.

[0005]

According to a first aspect of the present invention, an air outlet groove is provided between a cylindrical case, a coil housed in one end of the cylindrical case, and a coil. And a clamp portion provided at the other end of the cylindrical case and holding a cord and having an opening for filling with resin.

[0006] The invention according to claim 2 of the present application comprises a tubular case,
A coil case housed at one end of the cylindrical case and holding the coil, and a coil case provided with an air outflow groove between the cylindrical case and a cord provided at the other end of the cylindrical case, A clamp portion having an opening for resin filling, a printed circuit board mounted with an oscillation circuit fixed to the coil case and connected to the coil, and a shield film wrapping the printed circuit board; A proximity sensor having an opening provided near a coil case.

The invention of claim 3 of the present application is directed to claim 1 or 2
In the proximity sensor, the coil case is a bottomed cylindrical member, and a first linear projection intermittently provided on an outer peripheral surface thereof and a position corresponding to the projection of the first linear projection. And an intermittent second linear projection formed with an air outflow groove.

According to a fourth aspect of the present invention, in the proximity sensor according to the third aspect, a groove for storing a resin is formed between the first and second linear projections. .

According to a fifth aspect of the present invention, a coil case having an air outflow groove is attached to one end of a cylindrical case, and a cord is held at the other end of the cylindrical case, and an opening for resin filling is provided. Forming a proximity sensor by attaching a clamp portion having a pressure sensor, holding the proximity sensor in a mold, reducing the pressure in the cylindrical case, and injecting resin from a resin filling opening of the clamp portion. And filling the inside of the proximity sensor with a resin.

According to a sixth aspect of the present invention, in the method of manufacturing a proximity sensor according to the fifth aspect, a primary filling resin is poured into the coil case in a state where electronic components including a coil are housed in the coil case, and the primary filling is performed. After the resin is solidified, the coil case is attached to one end of the cylindrical case.

[0011]

FIG. 1 is an assembly configuration diagram of a proximity sensor according to a first embodiment of the present invention, and FIG. 2 is a longitudinal sectional view thereof. As shown in these figures, in the proximity sensor 1 according to the present embodiment, an annular groove is formed in the core 2, and the coil 4 wound around the coil spool 3 is provided inside the core 2.
In the annular groove. An elongated printed board 5 is connected to the back surface of the core 2 as shown in the figure, and a shield film 6 covering the oscillation circuit section of the printed board 5 is provided. The core 2 is stored in the coil case 7. The coil case 7 is a bottomed cylindrical member made of resin. On the outer peripheral portion inside the coil case 7, a projection shown is formed as described later. The coil case 7 is housed in a base fitting 8. The base fitting 8 is a metal cylindrical case having an opening on both sides with a thread groove formed on the outer periphery, and a clamp portion 9 is attached to the back surface thereof. The clamp 9 is a resin member that holds the cord 10.

Next, the coil case 7 will be described in more detail. FIG. 3A is a side view of the coil case 7, and FIG.
4 is a longitudinal sectional view, FIG. 4 is a sectional view taken along line AA, and FIG.
As shown in an enlarged cross-sectional view taken along the line B, it is a cylindrical member having a U-shaped cross section with a front surface covered. As shown, first linear projections 21a to 21d for preventing resin leakage are provided on the inner peripheral surface housed in the metal case 8. The linear projections 21a to 21d for preventing resin leakage are intermittent at four locations and are linear projections formed so as to substantially cover the circumference of the coil case 7. A second linear projection 22a for preventing resin leakage having a shorter length around the cutout portion of the linear projections 21a to 21d.
To 22d. First and second linear projections 21a to 21a
The notched portions of 21d and 22a to 22d serve as air outflow grooves. Furthermore, projections 23a to 23d having the same height as the linear projections 21a to 21d and having an arc-shaped cross section are provided at the middle positions of the cutouts. Furthermore, linear projections 22
At the intermediate position between a to 22d, projections 24a to 24d having the same height as that of the cross section are provided. These arc-shaped projections 23a to 23d and 24a to 24d are used when the coil case 7 is press-fitted into the base metal member 8.
Are held coaxially so as not to incline, so that the grooves for air outflow do not become uneven. As shown in FIGS. 3A and 3B, the open end of the coil case 7 has a notch 25a in which only portions not corresponding to the linear projections 22a to 22d are cut inward as shown. ~ 25
d. When the coil case 7 is stored in the base fitting 8, the innermost part thereof stops at the boundary where the thickness of the tip of the base fitting is slightly reduced. Therefore, the notches 25a to 25d are provided to secure an air outflow path when the coil case 7 is housed in the base fitting 8. Here, an intermediate portion between the linear projections 21a to 21d and the linear projections 22a to 22d is a groove 26 for resin accumulation.
It has become. Linear projections 21a to 21d and 22a to 2
As shown in FIG. 5, an inner portion 2d is provided with a slope, and a linear projection 22a is shown in FIG.
It is configured so that the thickness of the inner side of ２２22d is increased.

As shown in FIG. 4, the coil case 7 is provided at a portion where the linear projections 21a to 21d are cut out and at an intermediate portion thereof at every 45.degree. Eight ribs 27a-2 parallel to the cylindrical axis
7h are provided. These ribs 27 a to 27 h are provided for holding the core 2 coaxially with the coil case 7. Further, cross-shaped linear projections 28a to 28d are provided inside the front surface of the coil case 7, as shown in FIG.

Next, a detailed configuration of the clamp unit 9 will be described with reference to FIGS. The clamp 9 is shown in FIG.
7A is a front view, FIG. 7B is a side view, FIG. 7A is a bottom view, FIG. 7B is a rear view, and FIG. 8 is a longitudinal sectional view. The clamp portion 9 is configured such that a portion embedded in the base metal member 8 is a cylindrical portion 31 having an outer diameter substantially equal to the inner diameter of the base metal member 8, and two band-shaped protrusions 32 are provided inside the cylindrical portion 31. Further, a flange portion 33 is provided at the rear thereof. As shown in FIG. 8, the rear portion of the flange portion 33 is formed in a substantially semi-conical shape so as to have a substantially triangular cross section.
4 is provided, and a code holding portion 35 for elastically holding the code 10 is provided at the rear thereof. Code holding unit 35
Is formed with elongated slit-shaped openings 36 at predetermined intervals. The cross section of the cord holder 35 is shown in FIG.
7A and 7B, the cord 10 has an inner diameter corresponding to the outer shape of the cord 10.

Now, the cylindrical portion 3 inserted into the base fitting 8
As shown in the cross-sectional view of FIG. 8, a guide groove 37 for guiding both ends of the printed circuit board 5 of the proximity sensor and a tapered portion 38 are formed on the inner surface of 1. A substrate holding groove 39 is provided at the innermost side of the tapered portion 38. Substrate holding groove 39
Has a width substantially equal to the thickness of the printed circuit board 5, and has a linear projection 40 as shown in the figure. The linear projection 40 is deformed when the printed circuit board 5 is inserted.
This is for fixing the printed circuit board 5. Printed circuit board 5
When held in the substrate holding groove 39, one surface thereof faces the inner surface of the light guide 34. A display element 41 such as a light emitting diode is provided at this position on the printed circuit board 5.
Is implemented. Printed circuit board 5 on which display element 41 is mounted
Is mounted on the substrate holding groove 39 via the guide groove 37, the upper surface of the display element 41 substantially contacts the inner surface of the light guide 34. Even when a gap is generated during this time, the display element 41
8, the light of the display element 41 is guided to the light guide 34 via the transparent resin 42, and is directly or reflected from the light guide 34 as shown in FIG. The light is reflected by the surface 34a and emitted to the outside.

The diameter of the side of the flange 33 is enlarged in the clamp 9 as shown in the back view of FIG. 7A, and an opening 43 is provided inward in the direction of the back.
As shown in FIG. 6 (b), the opening 43 has a periphery 44 formed around it. This opening 43 is an opening for injecting a filling resin described later from the outside.

FIG. 9 is a perspective view showing a ring cord attached to the end of the cord 10. As shown in FIG. The cord 10 comprises a two-wire or three-wire cable, either of which is connected to the printed circuit board 5 by a proximity sensor. At this time, if two or three cables are drawn directly from the cord 10, there is a problem that the resin may enter the coating of the cord 10 when the resin is filled, and the diameter of the cord may expand. . This is a problem particularly in the case of the three-wire cable type cord shown in FIG. 9D because the resin easily enters between the cables. In order to solve this problem, a ring cord is attached to the end of the cord 10 in the present embodiment. The ring cord 45 is, as shown in FIG.
The cord holding part 35 of the clamp part 9 is attached to the end of the cord 10.
The ring cord 45, which is a resin having a shape corresponding to the above shape, is integrally formed as shown in FIG. 9B. In this way, the cord 10 to which the ring cord 45 is attached is accommodated in the cord attaching portion 35 having a step on the back surface of the clamp portion 10 as shown in FIG. 2, so that the cord 10 can be reliably prevented from falling off. Become.
Also, when pulling out each cable from the ring cord 45 with respect to the cord 10, even in the case of a three-wire system, three cables are arranged in parallel as shown in FIG. Etc. can be selected in any position and shape.

FIG. 10A is an assembly view showing the core 2 housed in the coil case 7 and the coil 4 wound on the coil spool 3, and FIG. 10B is a view seen from the opposite direction. As shown in these figures, an annular groove is formed in the core 2, and through holes 2a and 2b are provided on the back surface thereof.
The leads 4a, 4b at both ends of the coil are passed through the ends of the coil spool through the through holes 2a, 2b, and are connected to an oscillation circuit on a printed board (not shown).

Next, the manufacturing process of the proximity sensor according to the present embodiment will be described. The coil 4 wound around the coil spool 3 is housed 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 circuit board 5 and the shield film 6 is attached to the printed circuit board 5.
Wrap. Next, the core 2 is housed in the coil case 7 in this state, and is primarily filled in advance with an epoxy-based coil portion sealing resin 51 in order to stabilize the coil characteristics in advance. 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 circuit board 5. Next, the coil case 7 is stored in the base fitting 8. Then, the transparent resin 42 is put on the upper surface of the display element 41 of the printed circuit board 5 as described above,
Is inserted into the guide groove 37 and the holding groove 39 so that the clamp portion 9 is housed in the inner wall of the base fitting 8 to form a proximity sensor. In this case, the display element 41 comes into contact with the light guide section 34 of the clamp section 9 via the transparent resin 42.

The proximity sensor thus constructed is housed in a mold and brought into a vacuum state. In this case, the insides of the proximity sensor are linear projections 22a to 22d and 21a to 21d of the coil case 7.
Air is sucked outside through the air outflow groove in the gap 21d, and the pressure inside the proximity sensor also decreases. In this state, a high-temperature filling resin is injected from the opening 43 of the clamp 9 at a low pressure , for example, 5 to 20 atm. In this way, the filled resin hits the printed circuit board 5 and is then filled in the case and spreads over the entire case. At this time, by selecting the mold temperature to an appropriate value, the proximity sensor can be configured in a short time. At this time, air flows between the linear projections 21a to 21d and 22a to 22d in the direction of arrow C in FIG. 3, but the resin injected at a low pressure hits the linear projections 21a to 21d, and as shown in FIG. Since the filler accumulates in the accumulating groove 26, the filler does not leak out of the coil case 7 and can be retained in the base fitting 8. In this way, the manufacturing time can be significantly reduced, and the cost can be reduced.

Next, a proximity sensor according to a second embodiment of the present invention will be described. FIG. 11 is an assembly configuration diagram of the proximity sensor according to the second embodiment, and FIG. 12 is a longitudinal sectional view thereof. As shown in these figures, the clamp portion 61 of the present embodiment is a substantially conical member having an opening at the center as shown in FIG. 11, and the base fitting 8 side has a diameter so as to be equal to the inner diameter thereof. Are made smaller, and the inner diameter of the last code holding portion 62 of the proximity sensor is made smaller so as to be equal to the code 10. An opening 63 is provided in a side wall of the clamp portion 61. Other configurations are the same as those of the first embodiment.

FIG. 13 (a) is a diagram showing a process of filling the filling resin 52 from the opening 63 of the clamp portion 61 in the second embodiment. As described above, after filling the coil case of the proximity sensor 60 with the primary filling resin for sealing the coil portion indicated by the mark “x”, the mold is held in the mold at a pressure close to vacuum. When the resin indicated by the mark is filled from the opening 63 of the clamp portion 61, air is sucked from the gap of the coil case 7, and accordingly, the filled resin 52 sequentially enters the proximity sensor, and as shown in FIG. ), (B) and (c) as shown in FIG. At this time, since the inner diameter of the cord holding portion 62 of the clamp portion 61 is the same as that of the cord 10, the resin does not leak from the gap between the cords, and the filling resin 52 can be filled in the case.

Next, a third embodiment of the present invention will be described. In the proximity sensor according to the third embodiment, an opening is provided in the shield film 6 so that the resin can be reliably filled. If an opening is not provided in the shield film 6 when the diameter of the proximity sensor is small or the like, it is conceivable that air that cannot be completely removed remains in a region sandwiched between the coil portion sealing resin and the shield film 6 as shown in FIG. . For this reason, an opening is provided in the shield film 6, and the other parts are the same as in the second embodiment.

FIG. 15 is an assembly configuration diagram of a proximity sensor 70 according to the third embodiment, and FIG. 16A is a developed view showing an example of a shield film 71 used for this proximity sensor. The shield film 71 is made of a substantially rectangular flexible substrate, and has a cross-shaped pattern 72 formed on one surface thereof. A protruding portion 73 is provided at one end thereof, and ends 74a and 74b of the pattern 72 are provided.
Are formed. Two openings 75a and 75b are provided at the center of the conductive pattern of the shield film 71. A double-sided adhesive portion 76 is provided at the right end of the rectangular substrate. Such a shield film 71 is curved so as to wrap the printed circuit board 5 as shown in FIG. 16B, and one end thereof is wrapped and bonded in the area of the double-sided bonding portion 76. The shield film is wound so that the pair of openings 75a and 75b are located at positions corresponding to both ends of the printed circuit board 5. By doing so, the influence on the electronic circuit section on the printed circuit board 5 can be reduced.

FIG. 17 is a diagram showing a state in which the proximity sensor according to the third embodiment is filled with resin. As shown in this figure, when the resin is injected from the opening 63 while the proximity sensor is kept in a vacuum, the resin is sequentially filled from the vicinity of the clamp portion 61, and FIG.
(B) and (c) as shown in FIG.
1 filling section is reached. At this time, the through holes 75a and 75b are provided in the shield film 71, so that no air remains in the portion sandwiched between the shield film 71 and the printed circuit board 5, and the void is filled with the resin. . In this case, the environment resistance of the proximity sensor is improved. Further, as in the first embodiment, the resin filling operation can be performed very easily and reliably in a short time.

In the above-described third embodiment, two openings are formed in the shield film.
The same effect can be obtained by providing two openings.

[0027]

[0028]

Next, a fourth embodiment of the present invention will be described .
This will be described with reference to FIGS. The proximity sensor according to the present embodiment is an unshielded proximity sensor, and has a shape in which a coil case 7C protrudes outside the base metal member 8. For this reason, the coil case 7C has the linear projections 21a to 21d and 22a to 22c, as in the first embodiment.
22d and the like as they are, but these projections are formed near the base fitting 8 side. Then, as shown in FIG. 19 , in the base fitting 8, the depression holding the inner end surface of the coil case 7C is formed closer to the opening than in the first embodiment. By doing so, the coil case 7C can be fixed to the opening at the front of the base fitting 8, and the resin can be filled through the opening 43. Also in this embodiment, the air remaining in the case is discharged through the gap between the coil case 7C and the base fitting 8, and the resin 52
Can be filled.

[0030]

[0031]

[0032]

As described above in detail, according to the first to sixth aspects of the present invention, when filling the proximity sensor with the resin, the resin is maintained at a low pressure from the opening while maintaining the proximity sensor at a low pressure. , The resin can be reliably filled in the case. In this case, since the resin hardens in a short time, the number of working steps is reduced, and the manufacturing time can be greatly reduced. In the invention of claim 2, by providing an opening in the shield film covering the printed circuit board,
The effect that the resin can be reliably filled can be obtained.

[Brief description of the drawings]

FIG. 1 is an assembly configuration diagram of a proximity sensor according to a first embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of the proximity sensor according to the embodiment.

3A is a side view of a coil case of the proximity sensor according to the embodiment, and FIG. 3B is a longitudinal sectional view thereof.

FIG. 4 is a sectional view taken along line AA of the coil case according to the present embodiment.

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

FIG. 6A is a front view of a clamp unit according to the present embodiment, and FIG. 6B is a side view thereof.

FIG. 7A is a bottom view of the clamp unit according to the present embodiment, and FIG. 7B is a rear view thereof.

FIG. 8 is a longitudinal sectional view of a clamp unit according to the present embodiment.

9A is a perspective view showing a cord, FIG. 9B is a perspective view showing a ring cord according to the present embodiment, and FIGS.
(D) is a front view thereof.

FIGS. 10A and 10B are assembly diagrams of a core and a coil housed in a coil case.

FIG. 11 is an assembly configuration diagram of a proximity sensor according to a second embodiment of the present invention.

FIG. 12 is a longitudinal sectional view of the proximity sensor according to the present embodiment.

FIG. 13 is a diagram illustrating a state of filling the resin when filling the proximity sensor according to the second embodiment;

FIG. 14 is a diagram showing a state in which resin is not completely filled in the second embodiment.

FIG. 15 is an assembly configuration diagram of a proximity sensor according to a third embodiment of the present invention.

16A is a development view of a shield film, and FIG.
FIG. 3 is a cross-sectional view of a proximity sensor wound with a shield film.

FIG. 17 is a diagram showing a state in which the proximity sensor according to the third embodiment is filled with resin.

FIG. 18 is an assembly configuration diagram of a proximity sensor according to a fourth embodiment of the present invention.

FIG. 19 is a longitudinal sectional view of the proximity sensor according to the present embodiment.

FIG. 20 is a sectional view showing an example of a conventional proximity sensor.
You.

[Explanation of symbols]

1, 60, 70 Proximity sensor 2 Core 3 Coil spool 4 Coil 5 Printed circuit board 6, 71 Shielding film 7, 7C Coil case 8 Base fitting 9, 60 Clamp member 10 Code 21a to 21d First linear projection 22a to 22d 2 linear projections 23a to 23d, 24a to 24d projections 25a to 25d notch portion 26 resin leakage prevention groove 31 cylindrical portion 32 band-shaped projection 33 flange portion 34 light guide portion 34a reflection surface 35 cord holding portion 36 opening 37 guide groove 38 Tapered portion 39 Substrate holding groove 40 Linear projection 41 Display element 43 Opening 45 Ring code 61 Cylindrical portion 62 Code holding portion 63, 103 Resin injection port 72 Pattern 73 Projecting portion 74a, 74b Terminal 75a, 75b Opening 76 Double-sided adhesive portion

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kyoji Kitamura 10th Hanazono Todocho, Ukyo-ku, Kyoto, Kyoto Prefecture Within (72) Inventor Kazuhiro Hayashi 10th Hanazono Todocho, Ukyo-ku, Kyoto, Kyoto Omron Stocks In-house (72) Inventor Niimi Pro Parent Omron Co., Ltd. (10) Hanazono Dodocho, Ukyo-ku, Kyoto-shi (72) Inventor Toshiki Kitani Omron Co., Ltd. (10) Hanazono-Todocho, Ukyo-ku, Kyoto, Kyoto Inventor Satoshi Noda 10-10 Hanazono Todocho, Ukyo-ku, Kyoto, Kyoto Prefecture (56) References JP-A-2-213199 (JP, A) JP-A 4-157757 (JP, A) JP-A-5 157500 (JP, A) JP-A-6-60763 (JP, A) JP-A 64-22040 (JP, U) JP-A-5-6625 (JP, U) JP-A 3-79143 (JP U) Shokai Sho 62-104347 (JP, U) JP-B 4-72193 (JP, B2) JP-B 2-38358 (JP, Y2) JP-B 3-388753 (JP, Y2) (58) Survey Field (Int.Cl. ⁷ , DB name) H01H 36/00 H05K 5/00-5/06

Claims (6)

(57) [Claims] 1. A cylindrical case, a coil case housed at one end of the cylindrical case and holding a coil, and an air outflow groove provided between the cylindrical case and the cylindrical case; A clamp provided at an end for holding a cord and having an opening for resin filling. 2. A cylindrical case, a coil case housed at one end of the cylindrical case and holding a coil, and an air outflow groove provided between the cylindrical case and the coil case; A clamp portion provided at an end and holding a cord, having a resin filling opening, a printed circuit board mounted with an oscillation circuit fixed to the coil case and connected to the coil, and a shield film wrapping the printed circuit board Wherein the shield film has an opening in the vicinity of the coil case. 3. The coil case is a cylindrical member with a bottom, a first linear projection intermittently provided on an outer peripheral surface thereof, and a position corresponding to the projection of the first linear projection. The proximity sensor according to claim 1, further comprising a second linear projection formed with an air outflow groove formed therein and intermittent. 4. The proximity sensor according to claim 3, wherein a groove for storing a resin is formed between said first and second linear projections. 5. A coil case having an air outflow groove is attached to one end of a cylindrical case, and a clamp portion holding a cord and having an opening for resin filling is attached to the other end of the cylindrical case. constitute a proximity sensor, while holding the proximity sensor in the mold within the tubular casing
A method of manufacturing a proximity sensor, wherein the proximity sensor is filled with resin by lowering pressure and injecting resin from a resin filling opening of the clamp portion. 6. A primary filling resin is poured into a coil case in a state where electronic components including a coil are housed in the coil case, and after the primary filling resin is solidified, the coil case is attached to one end of a cylindrical case. The method for manufacturing a proximity sensor according to claim 5, wherein: