JPH0955153A - Proximity sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily assemble a proximity sensor which is constituted by connecting a printed board to a ferrite core and winding a shield film around it. SOLUTION: A projecting part 62 is provided on a shield film 6 and electrodes 63a, 63b are provided at the end of a pattern. A projecting part 5a of a printed board 5 is made to penetrate by an opening 64 so as to be engaged with a linear groove 2c of a core 2. The shield film 6 is thus positioned in relation to the core 2 and the printed board 5 so as to be easily connected.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a proximity sensor,
In particular, the present invention relates to a proximity sensor characterized by a shield film that shields a printed circuit board in a case.

[0002]

2. Description of the Related Art FIG. 16 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 a resin coil case 105 as shown in the drawing, and these are housed in a metal case 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. Then, a shield film 109 is wound around the outer peripheral surface of the printed board 108. A conductor material is vapor-deposited and shielded on the outer peripheral surface of the core 102, and the core 102 is directly connected to the ground surface of the printed circuit board 108 by soldering as shown in FIG. In addition, as shown in FIG. 18 and FIG. 19 which are sectional views and assembly configuration diagrams of other proximity sensors,
There is also a structure in which the ground pattern of the printed circuit board 108 and the connection pattern of the core 102 are connected via a thin relay member 110. FIG. 20 is a diagram showing a shield pattern of the conventional shield film 109.
As shown in the figure, the shield pattern is composed of a large number of parallel linear patterns and a central connecting pattern for connecting the linear patterns.

[0003]

However, in such a conventional proximity sensor, as shown in FIG. 17, when the back surface of the ferrite core 102 and the circuit board are directly soldered, during assembly work or use. There is a drawback that the conductor material attached to the ferrite core is easily peeled off due to stress such as environmental change. Further, as shown in FIG. 19, when the printed circuit board 108 and the back surface of the ferrite core 102 are connected via the relay component 110, the relay component 10
Since 0 increases, assembly workability is poor, and there are disadvantages that the number of soldering points increases. In addition to the increase in the number of parts, the relay parts are small in size, which makes them difficult to handle.

In all of these conventional examples, it is difficult to properly position the shield film, and workability is poor. Further, there is a drawback in that variations in finish are likely to occur even after manufacturing. Further, in the shield pattern as shown in FIG. 20, since the positions of the connecting patterns are the same, the shield film is not flexible only in that position, and it is difficult to wind the shield film around the printed circuit board.

The inventions of claims 1 and 2 of the present application have been made in view of such conventional problems, and a shield film can be easily connected to the back surface of the ferrite core and can be easily manufactured. The purpose is to

[0006]

According to a first aspect of the present invention, there is provided a cylindrical case, a core which is housed at one end of the cylindrical case and holds a coil, and which has a ground pattern and a groove on its back surface. An electronic circuit unit connected to the coil for detecting the proximity of an object is mounted, a printed circuit board having a projection formed on the front surface thereof for fitting in the groove of the core, a flat surface section having a shield pattern formed thereon, and the shield pattern. An electrode that is connected to the core and the printed circuit board, and a protrusion that is formed in the vicinity of the electrode and that includes an opening that penetrates the protrusion of the printed circuit board, and encloses at least a part of the printed circuit board. And a shield film.

In this way, the shield film is held and positioned by penetrating the protrusion of the printed board through the opening of the shield film and inserting it into the groove of the core. In this state, the electrodes of the shield film are connected to the core and the printed circuit board, respectively, so that the pattern of the shield film is connected to the ground pattern. Then, the proximity sensor is configured by winding the shield film around a part of the printed circuit board and housing it in the case.

The invention according to claim 2 of the present application comprises a cylindrical case,
A core is provided which is housed at one end of the cylindrical case and holds a coil, and which has a ground pattern on the back surface thereof, a printed circuit board on which an electronic circuit unit connected to the coil for detecting the proximity of an object is mounted, and a shield pattern. A flat portion formed and a projection portion including electrodes connected to the shield pattern and connected to the core and the printed circuit board, respectively,
A shield film that wraps at least a part of the printed circuit board, wherein the shield pattern of the shield film has linear shield patterns that are parallel to each other and that are formed on substantially the entire flat surface of the shield film. And a connecting pattern to be connected, and the connecting position of the connecting pattern is different between two adjacent lines.

According to the second aspect of the present invention, the shield pattern is composed of the linear pattern and the connecting pattern, and the connection position of each pattern is formed between two adjacent lines. It is possible to easily wind around.

[0010]

1 is an assembly configuration diagram of a proximity sensor according to a first embodiment of the present invention, and FIG. 2 is a vertical sectional view thereof. As shown in these figures, in the proximity sensor 1 according to the present embodiment, an annular groove is formed in a core 2, and a coil 4 wound around a coil spool 3 is housed in the annular groove of the core 2 inside. There is. 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. The core 2 is housed in the coil case 7. The coil case 7 is a bottomed cylindrical member made of resin.
On the inner peripheral portion of the coil case 7, there is formed a protrusion as shown in the drawing, which will be described later. 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 resin member and holds the cord 10.

Next, the coil case 7 will be described in more detail. The coil case 7 is a side view in FIG. 3A, and FIG.
Fig. 4 is a longitudinal sectional view thereof, Fig. 4 is a sectional view taken along line AA, and Fig. 5 is a sectional view thereof.
As shown in the enlarged cross-sectional view taken along the line B, this is a cylindrical member having a U-shaped cross section with the front surface covered. Then, as shown in the drawing, first linear projections 21a to 21d for preventing resin leakage are provided on the inner peripheral surface accommodated in the metal case 8. The linear protrusions 21a to 21d for preventing resin leakage are linear protrusions which are intermittently formed at four locations and are formed so as to substantially cover the circumference of the coil case 7. The second linear projection 22a for preventing resin leakage having a length shorter than this is centered on a portion where the linear projections 21a to 21d are further cut out inside thereof.
~ 22d are provided. First and second linear protrusions 21a to
The notched portions of 21d and 22a to 22d become air outflow grooves. Further, protrusions 23a to 23d having an arc-shaped cross section having the same height as that of the linear protrusions 21a to 21d are provided at the notched intermediate positions. Further, the linear protrusion 22a
Projections 24a to 24d having an arcuate cross-section and having the same height as the projections 22a to 22d are provided at intermediate positions. These arcuate projections 22a to 22d and 24a to 24d hold the coil case 7 coaxially so that the coil case 7 does not tilt when the coil case 7 is press-fitted into the metal case 8 so that the grooves for air outflow do not become uneven. It is for doing. As shown in FIGS. 3 (a) and 3 (b), the opening end of the coil case 7 has a notch 25a in which only the portions not corresponding to the linear protrusions 22a to 22d are inwardly cut as shown. ~ 25d
have. When the coil case 7 is housed in the metal case 8, the innermost side of the coil case 7 comes into contact with the boundary part where the thickness of the tip part of the metal case is slightly thinned and stops. Therefore, the notches 25a to 25d are provided to secure the outflow path of air when the coil case 7 is housed in the metal case 8. 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. Linear protrusions 21a to 21d and 22a to 22
As shown in the enlarged cross-sectional view taken along line BB of FIG. 3A in FIG.
The inner wall of 22d is thickened.

Further, as shown in FIG. 4, the coil case 7 is arranged inwardly from the front surface of the proximity sensor inside the cylinder at an angle of 45 ° at the cutout portions of the linear projections 21a to 21d and the intermediate portion thereof. Eight ribs 27a-2 parallel to the cylinder axis
7h is provided. These ribs 27a to 27h are provided to hold the core 2 coaxially with the coil case 7. Further, as shown in FIG. 4, cross-shaped linear protrusions 28a to 28d are provided on the inside of the front surface of the coil case 7.

Next, the detailed structure of the clamp portion 9 will be described with reference to FIGS. The clamp part 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 back view, and FIG. 8 is a longitudinal sectional view. A portion of the clamp portion 9 embedded in the base metal fitting 8 is configured as a cylindrical portion 31 having an outer diameter substantially equal to the inner diameter of the base metal fitting 8, and two strip-shaped projections 32 are provided inside thereof. A flange portion 33 is provided behind it. The rear portion of the flange portion 33 has a substantially semi-conical shape so that the cross section thereof has a substantially triangular shape as shown in FIG.
4 is provided, and a cord holding portion 35 that elastically holds the cord 10 is provided behind it. Code holding unit 35
Is an elongated slit-shaped opening 36 formed at predetermined intervals. The cross section of the cord holding portion 35 is shown in FIG.
As shown in FIGS. 7A and 7B, the cord 10 has an inner diameter corresponding to the outer shape of the cord 10.

Now, the cylindrical portion 3 to be inserted into the metal case 8
As shown in the sectional view of FIG. 8, a guide groove 37 and a taper portion 38 for guiding both ends of the printed circuit board 5 of the proximity sensor are formed on the inner surface of 1. A substrate holding groove 39 is provided on the innermost side of the tapered portion 38. Substrate holding groove 39
Has a width approximately equal to the thickness of the printed circuit board 5 and has linear protrusions 40 formed as shown. The linear protrusion 40 is deformed when the printed circuit board 5 is inserted,
The printed circuit board 5 is fixed. Printed circuit board 5
While being held in the substrate holding groove 39, one surface thereof faces the inner surface of the light guide section 34. At this position of the printed board 5, a display element 41 such as a light emitting diode is provided.
Will be implemented. Printed circuit board 5 on which display element 41 is mounted
When is mounted in the substrate holding groove 39 via the guide groove 37, the upper surface of the display element 41 substantially comes into contact with the inner surface of the light guide portion 34. Even if there is a gap between them, the display element 41
By swelling the transparent resin 42 on the upper surface of the display element 41 in advance as shown in FIG. 8, the light of the display element 41 is guided to the light guide section 34 through the transparent resin 42 and directly or reflected from the light guide section 34. The light is reflected by the surface 34a and emitted to the outside.

As shown in the rear view of FIG. 7 (a), the clamp portion 9 has an enlarged lateral diameter of the flange portion 33, and an opening 43 is provided inwardly toward the rear surface.
An edge 44 is formed around the opening 43 as shown in FIG. 6 (b). This opening 43 is an opening for injecting a filling resin described later from the outside.

FIG. 9A is an assembly view showing the core 2 housed in the coil case 7 and the coil 4 wound around the coil spool 3, and FIG. 9B is a view seen from the opposite direction.
As shown in these figures, the core 2 is formed with an annular groove,
Through holes 2a and 2b are provided on the back surface thereof. The leads 4a and 4b at both ends of the coil are made to penetrate from the ends of the coil spool through the through holes 2a and 2b, and are connected to the oscillation circuit of the printed circuit board 5. A linear groove 2c is provided in the center of the back surface of the core 2.

FIG. 10 is a perspective view showing an assembled state of the core 2, the printed circuit board 5, and the shield film 6 wound around the printed circuit board 5. As shown in these figures, a protrusion 5a corresponding to the width of the linear groove 2c of the core 2 is formed at the tip of the printed circuit board 5. The shield film 6 is composed of a thin flexible substrate, and its development view is shown in FIG. A hairpin pattern 61 is formed on one surface of the shield film 6. A protrusion 62 is provided on one end of the electrode 6 of the pattern 61.
3a and 63b are formed. Further, a rectangular opening 64 corresponding to the straight groove 2c of the core 2 is provided at a substantially central portion of the protruding portion 62, as shown in the drawing. An adhesive surface 65 is provided on the shield film 6 at the hatched portion in the figure.

The shield pattern 61 is composed of a large number of parallel linear patterns 61a as shown in the figure and a connecting pattern 61b for connecting the linear patterns 61a. Then, the connection positions of the connection patterns are configured to be different positions between two adjacent lines, for example, in the example of FIG. 11, the connection positions are alternately located at the ends of the shield pattern and slightly inside thereof. There is. FIG. 12 is a diagram showing another example of the shield film 6A. Similarly, the pattern 66 of the shield film 6A is also composed of a large number of parallel linear patterns and a connecting pattern, and the connecting pattern is formed both on the protrusion side and at a position symmetrical to this. Also in this case, the positions of the connecting patterns are made different between the two adjacent lines.

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. At this time, as shown in FIG. 10, the opening 5 of the shield film 6 is inserted through the projection 5a of the printed circuit board 5 and fitted into the linear groove 2c of the core 2. In this way, one end of the shield film 6 is positioned and held between the printed board 5 and the core 2. Next, the electrode 63a of the protruding portion 62 of the shield film 6 is connected to the vapor deposition portion on the back surface of the core 2 and the electrode 63b is connected to the ground pattern of the printed board 5 by soldering. The adhesive surface 65 of the shield film 6 is adhered to the other end of the printed circuit board in a rolled state so that the film has an elliptical cross section and covers the front end of the printed circuit board. 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. The upper surface of the display element 41 of the printed board 5 is covered with the transparent resin 42 as described above, and the clamp portion 9 is housed in the inner wall of the base metal fitting 8 so that the printed board 5 is inserted into the guide groove 37 and the holding groove 39. Configure a proximity sensor. By doing so, the display element 41 comes into contact with the light guide portion 34 of the clamp portion 9 via the transparent resin 42.

The proximity sensor thus constructed is housed in a mold to be in a vacuum state. By doing so, the inside of the proximity sensor is provided with linear projections 22a to 22d and 21a to 22a of the coil case 7.
Air is sucked to the outside through the air outflow groove in the gap 21d, and the pressure inside the proximity sensor also drops. In this state, the high temperature filling resin is injected from the opening 43 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, is then filled in the case, and spreads over the entire case. At this time, the proximity sensor can be configured in a short time by selecting the mold temperature to an appropriate value. 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. 3, but the resin injected at low pressure hits the linear projections 21a to 21d, and as shown in FIG. Since the filling material is collected in the collecting groove 26, the filling material can be retained in the metal case 8 without leaking out of the coil case 7. By setting the shield film 6 as shown in FIG. 11, the coupling pattern does not approach the vicinity of the core, and the eddy current loss can be reduced.

FIG. 13 shows a proximity sensor 70 according to the second embodiment.
14A is an exploded view showing an example of the shield film 71 used in this proximity sensor.
The shield film 71 is made of a substantially rectangular flexible substrate, and a hairpin pattern 72 is formed on one surface thereof. And at one end of the protrusion 73
Are provided and end portions 74a and 74b of the pattern 72 are formed. Two openings 75a and 75b are provided in the central portion of the conductive pattern of the shield film 71. A double-sided adhesive surface 76 is provided on the right end of the rectangular substrate. Such a shield film 71 is shown in FIG.
As shown in (b), the printed circuit board 5 is curved so as to wrap it, and one end thereof is wrapped and bonded in the area of the double-sided adhesive surface 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. This can reduce the influence on the electronic circuit section on the printed circuit board 5. In FIG. 13, the clamp portion 81 is provided with an opening 82 for filling the resin.

FIG. 15 is a view showing a state when resin is filled in the proximity sensor according to the second embodiment thus constructed. As shown in the figure, when the resin is injected through the opening 82 while the proximity sensor is kept in vacuum, the clamp portion 61
15b, the resin is sequentially filled from the vicinity of
As shown in (c), the resin reaches the filled portion of the coil portion sealing resin 51. At this time, since the through holes 75a and 75b are provided in the shield film 71, air does not remain in the portion sandwiched between the shield film 71 and the printed circuit board 5, and the void is filled with the resin. . This improves the environment resistance of the proximity sensor. Further, like the first embodiment, the resin filling operation can be performed extremely easily and reliably in a short time.

In the second embodiment described above, two openings of the shield film are formed, but the same effect can be obtained by providing at least one opening.

[0024]

As described in detail above, according to the invention of claim 1 of the present application, a connection pattern is formed on the shield film for shielding the circuit board of the proximity sensor, and the back surface of the core is formed through this pattern. And the printed circuit board are connected for positioning. Therefore, positioning during soldering becomes easy, and workability during soldering and winding of the shield film can be improved. Further, since the connection can be made without using the relay parts and the flexible shield film is connected to the core, the effect that the peeling of the vapor deposition portion can be eliminated can be obtained.

According to the second aspect of the invention, since the position of the connecting pattern of the shield film is changed for each position of the linear pattern, the shield film becomes flexible. Therefore, the shield film can be easily wound around the printed circuit board, and the assembly can be easily performed.

[Brief description of 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 vertical sectional view of a proximity sensor according to the present embodiment.

3A is a side view of a coil case of the proximity sensor according to the present embodiment, and FIG. 3B is a vertical 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 portion according to the present embodiment,
(B) is a side view thereof.

FIG. 7A is a bottom view of the clamp portion according to the present embodiment,
(B) is the back view.

FIG. 8 is a vertical sectional view of a clamp portion according to the present embodiment.

9A and 9B are assembly diagrams of a core and a coil housed in a coil case.

FIG. 10 is a perspective view showing a connection state of the core, the shield film, and the printed board according to the present embodiment.

FIG. 11 is a front view showing an example of a shield pattern of the present embodiment.

FIG. 12 is a front view showing another example of the shield pattern according to the present embodiment.

FIG. 13 is an assembly configuration diagram of a proximity sensor according to a second embodiment of the present invention.

FIG. 14A is a development view of a shield film, and FIG.
FIG. 6 is a cross-sectional view of a proximity sensor wound with a shield film.

FIG. 15 is a diagram showing a state in which resin is filled in the proximity sensor according to the third embodiment.

FIG. 16 is a sectional view showing an example of a conventional proximity sensor.

FIG. 17 is a perspective view showing an assembled state of a conventional core, a printed board, and a shield film.

FIG. 18 is a sectional view showing another example of a conventional proximity sensor.

FIG. 19 is a perspective view showing an assembled state of a core of a conventional proximity sensor, a printed board, a shield film, and a relay film.

FIG. 20 is a front view showing an example of a pattern of a conventional shield film.

[Explanation of symbols]

 1,70 Proximity sensor 2 Core 3 Coil spool 4 Coil 5 Printed circuit board 5a Projection part 6,6A, 71 Shield film 7 Coil case 8 Base metal fitting 9,81 Clamp member 10 Code 21a-21d First linear projection 22a-22d Second linear protrusions 23a to 23d, 24a to 24d Protrusions 25a to 25d Cutout portion 26 Resin leak prevention groove 31 Cylindrical portion 32 Belt-shaped protrusion 33 Flange portion 34 Light guide portion 34a Reflecting surface 35 Code holding portion 36 Opening 37 Guide Groove 38 Tapered portion 39 Substrate holding groove 40 Linear protrusion 41 Display element 43,82 Opening 61,66 Shield pattern 61a Linear pattern 61b Connection pattern 62 Projection 63a, 63b Electrode 64 Opening 65 Adhesive surface

Claims (2)

[Claims] 1. A tubular case, a core housed at one end of the tubular case for holding a coil, and having a ground pattern and a groove on its back surface, and an electronic circuit connected to the coil for detecting the proximity of an object. Part is mounted, a printed circuit board having a projection formed on the front surface thereof to be fitted in the groove of the core, a flat part having a shield pattern formed, and the shield pattern are connected to the core and the printed circuit board, respectively. A shield film having an electrode and a protrusion formed near the electrode and including an opening for penetrating a protrusion of the printed circuit board, and a shield film enclosing at least a part of the printed circuit board. Sensor. 2. A tubular case, a core which is housed at one end of the tubular case and holds a coil, and which has a ground pattern on its back surface, and an electronic circuit section which is connected to the coil and detects the proximity of an object. A printed circuit board mounted thereon; a flat surface portion on which a shield pattern is formed; and a protrusion portion including electrodes connected to the shield pattern and connected to the core and the printed circuit board, respectively, and at least a part of the printed circuit board. And a shield film for wrapping, wherein the shield pattern of the shield film has linear shield patterns that are parallel to each other and are formed on substantially the entire plane portion, and a connecting pattern that connects the respective linear patterns. A proximity sensor, wherein the connection positions of the connection pattern are different between two adjacent lines.