JP4214396B2 - Sensor device - Google Patents

Description

  The present invention relates to a sensor device in which a detection circuit is electrostatically shielded.

  In an inductive proximity sensor, an insulating flexible film having a conductor pattern is wrapped around a printed wiring board on which a circuit portion is mounted, and the printed wiring board is electrostatically shielded. It is known to solder to a film (see Patent Document 1).

Also, in a coil device in which a coil winding is applied to a magnetic core, it is known to wind a thin wire of a metal magnetic material such as permalloy or silicon rope around the coil winding to magnetically shield the coil winding. (See Patent Document 2).
Japanese Patent Laid-Open No. 56-1436 JP 11-195542 A

  In the proximity sensor adopting the electrostatic shield structure described in Patent Document 1, a film with copper foil with a high member cost obtained by performing secondary processing on a complicated shape is required for each model, It takes time and labor to wrap a film with copper foil on a circuit board by hand, and the assembly man-hours are large. It is difficult to automate winding a film with copper foil with a complicated shape on a circuit board. The number of man-hours for soldering the copper foil part of the attached film to the GND pattern of the circuit board is large, the automation of soldering the copper foil part of the film with copper foil to the GND pattern of the circuit board is difficult, A more complex film with an electrostatic shield copper foil provided with lead wires and joints for electrically joining the metal deposition part of the core and the GND pattern of the circuit board is required, and the metal deposition part of the core and the circuit It is difficult to automate the soldering of the board's GND pattern with the lead wire or film with copper foil, and the surface of the film with copper foil is secured to ensure insulation from electronic parts and exterior cases. It is necessary to apply an insulating layer. Therefore, a film with a high copper foil is necessary. Because the insulating layer is relatively thin, the surface is peeled off by rubbing against the edge of the circuit board, etc. And problems such as the possibility of short circuiting with circuit patterns are pointed out.

  In the shield structure described in Patent Document 2, the shield target is not a circuit board but a coil, and a magnetic material wire is wound thickly for the purpose of a magnetic shield. It was not suitable for the purpose of electrostatic shielding.

  The present invention has been made paying attention to the above-mentioned problems, and an object of the present invention is to provide a sensor device that can easily perform electrostatic shielding of a detection circuit.

  Still other objects and operational effects of the present invention will be easily understood by those skilled in the art with reference to the following description of the specification.

In the sensor device of the present invention, a covered electric wire is wound around a detection circuit board on which electronic components constituting the detection circuit are mounted for electrostatic shielding.

According to such a configuration, a conductor layer formed by winding a covered electric wire in a planar shape is formed around a detection circuit board on which electronic components constituting a detection circuit that is generally susceptible to noise in a sensor device are mounted. From this, the detection circuit can be electrostatically shielded by, for example, grounding the covered electric wire to stabilize its potential. For the purpose of electrostatic shielding, the material of the core wire of the covered electric wire is preferably a material having a small electric resistance such as copper, and does not need to contain a magnetic material.

  For the purpose of electrostatic shielding, it is sufficient that the covered electric wire is wound thinly. For example, the covered electric wire may be spirally wound around the detection circuit in a single manner. In this way, the thickness of the shield layer can be minimized while obtaining the effect of electrostatic shielding, so that the sensor device can be easily downsized.

  The sensor device may include a detection circuit board provided with a detection circuit and a cylindrical case. In one embodiment of the present invention in such a case, the covered electric wire is wound around the detection circuit board in a cylindrical surface shape, and the axial direction of the cylindrical surface coincides with the axial direction of the case. With such a configuration, the space in the case can be used effectively.

  One embodiment of the sensor device according to the present invention is a proximity sensor device including a detection coil having a core, and the detection circuit includes an oscillation circuit having the detection coil as a resonance element. The proximity sensor device includes a product called a proximity switch.

  In the proximity sensor device as an embodiment of the sensor device according to the present invention, a metal film for electrostatically shielding the detection coil is provided on the outer surface of the core, and the covered electric wire is electrically connected to the metal film of the core. Also good. In this way, the detection coil can also be electrostatically shielded.

  In this case, a detection circuit board provided with a detection circuit is provided, and both ends of the covered electric wire are electrically connected to the metal film of the core, and are electrically connected to the ground pattern of the detection circuit board at the intermediate portion thereof. You may make it do. The connection part between the covered wire and the metal film of the core is a part that is subject to stress due to filling resin, etc., but if both ends of the covered wire are connected, even if one of the connections is cut off, The electrostatic shield is maintained.

  The winding of the detection coil of the proximity sensor device is required to have a high density of the core wire when wound, but a high coating strength is not required. On the other hand, the coated electric wire wound around the detection circuit is not required to have a high density of the core wire when wound, but an unintended electrical short circuit with the detection circuit must be prevented. For this purpose, it is preferable that the covering strength of the covered electric wire used for shielding is higher than the covering strength of the covered electric wire used as the winding of the detection coil.

  However, if there is no fear of a short circuit between the covered wire and the detection circuit, the covered wire used for the shield and the covered wire used as the winding of the detection coil can be the same type. In this way, the manufacturing process can be simplified.

  Another embodiment of the sensor device according to the present invention includes a light receiving element that receives light from a detection target region and converts it into an electrical signal, and outputs a signal related to the state of the detection target region based on the output of the light receiving element. Device. Photoelectric sensor devices include photoelectric switches and products called photomicrosensors and photomicroswitches. The detection circuit in the photoelectric sensor device may be a simple derivation path for the output signal of the light receiving element, but in many cases includes a light receiving circuit that amplifies the output signal of the light receiving element. In the case of including a determination circuit that determines the detection target based on the output of the light receiving circuit, the determination circuit portion can also be included in the electrostatic shield target. In the case of a photoelectric sensor device further comprising a light projecting element, a light projecting circuit that emits light from the light projecting element, and a central processing circuit that controls the light projecting circuit and discriminates the detection target based on the output of the light receiving circuit. The part of the central processing circuit can also be included in the electrostatic shield.

  In the photoelectric sensor device according to the present invention, the covered electric wire can be wound around the light receiving element in a planar shape. If it does in this way, not only a detection circuit but a light receiving element can be electrostatically shielded by the process of winding a covered electric wire.

  An embodiment of the photoelectric sensor device according to the present invention includes a detection circuit board provided with a detection circuit, a cylindrical case, and a substantially halved cylindrical substrate holder that supports the detection circuit board and is accommodated in the case. Further, the covered electric wire is wound in a planar shape around the detection circuit board and the board holder. The covered electric wire may be wound around the light receiving element in a planar shape.

  According to this invention, the electrostatic shield of the ground detection circuit of the sensor device can be easily performed.

  Hereinafter, a proximity sensor according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. An exploded perspective view of a proximity sensor to which the winding shield structure of the present invention is applied is shown in FIG. This proximity sensor was previously proposed by the present applicant (International Publication No. 02/075763 pamphlet), and all the parts constituting the proximity sensor are integrated into several modules. The assembly man-hours can be reduced and the cost can be reduced.

  That is, the components of the proximity sensor are integrated into a detection end module SMJ (details will be described later), a connection member module CMJ (details will be described later), and an output circuit module OMJ (details will be described later).

  The detection end module (SMJ) will be described. The detection end module (SMJ) includes a detection coil 4 wound around a resin spool 3, a ferrite core 5 on which the detection coil 4 is mounted, and a resin coil case 1 that houses the detection coil 4 and the ferrite core 5. And a detection circuit board 6 on which a detection circuit including an oscillation circuit having the detection coil 4 as a resonance element is mounted. The detection coil 4 and the detection circuit board 6 are connected by soldering the coil terminal pins 39 and 40 on the detection coil 4 side to the connection pads 61 and 62 on the detection circuit board 6 side. An assembly in which the spool 3 around which the detection coil 4 is wound, the ferrite core 5 and the detection circuit board 6 are integrated is accommodated in the resin coil case 1, and then the primary note is placed in the coil case 1. Filled with mold resin. In addition, what is shown by the code | symbol 2 is the ring-shaped mask conductor inserted by the outer periphery of the front-end | tip part of the coil case 1, and, as previously proposed by the present applicant, due to the presence of this mask conductor 2, the detection end is detected. The module (SMJ) is self-contained so that the characteristics of the module (SMJ) are constant regardless of the presence or absence of the outer shell case 13 and the difference in material.

  Next, the connection member module (CMJ) will be described. The connection member module (CMJ) is composed of a harness 7 that is a film-like wiring board. On the harness 7, a plurality of wiring patterns are formed in parallel along the longitudinal direction. The harness 7 is in a state where its middle portion is folded into a V shape, and it is easy to handle the outer shell case 13 having various lengths.

  Next, the output circuit module (OMJ) will be described. The output circuit module (OMJ) is configured around an output circuit board 8 on which an output circuit IC9, a light emitting diode 10, and the like are mounted. Terminal pads 11 a and 11 b are provided at the rear end portion 12 of the output circuit board 8.

  The detection end module described above (including the coil case 1, the mask conductor 2, the spool 3, the detection coil 4, the ferrite core 5, and the detection circuit board 6) is connected to the output circuit module (including the output circuit board 8). They are connected to each other via member modules (including the harness 7) and are accommodated in a cylindrical outer shell case 13 having both ends opened. At this time, the opening of the front end of the outer shell case 13 is closed by the coil case 1 being press-fitted. Further, the rear end opening of the outer shell case 13 is closed with an end plug 15. At the rear end portion of the end plug 15, there are a slit 16 from which the rear end portion 12 of the output circuit board 8 protrudes, an injection port 17 used for injecting the secondary casting resin, and internal air at the time of resin injection. And a pleat portion 19 for promoting fusion with the resin constituting the cord protector 20 is formed on the outer periphery of the rear end portion.

  The detection end module (SMJ), the connection member module (CMJ), and the output circuit module (OMJ) are accommodated in the outer shell case 13, and the rear opening of the outer shell case 13 is closed with the end plug 15. By injecting the pressurized molten resin from the injection port 17, the gap in the outer shell case 13 is filled with the secondary casting resin to seal intrusion of water or oil from the outside. After that, the electric cord 21 is soldered to the terminal pads 11a and 11b of the rear end portion 12 of the output circuit board 8 protruding from the slit 16 of the end plug 15, and subsequently introduced into a predetermined molding die. The protector 20 is insert-molded. As a result, a cord-fixed proximity sensor is completed.

  A longitudinal section of the proximity sensor thus completed is schematically shown in FIG. In the figure, 27 is a primary casting resin, 28 is a sealing resin for sealing the detection circuit board 6, and 29 is a secondary casting resin for sealing a gap in the outer shell case 13. Further, 21 is an electric cord, 22 is an outer skin, 23 and 24 are core wires, and 25 and 26 are conductors.

  Thus, the primary casting resin 27 and the secondary casting resin 29 are filled in the outer shell case 13 of the proximity sensor that is a completed product.

  Next, FIG. 3 shows a partial sectional perspective view of the proximity sensor in a state where the primary casting resin 27 and the secondary casting resin 29 are removed. What is indicated by reference numeral 31 in the figure is a planar winding portion of the covered electric wire. As will be described in detail later, the planar winding portion 31 is obtained by winding the covered electric wire 30 in a planar shape around the wide portion of the detection circuit board 6, and by grounding this, the detection circuit board 6 is grounded. An electrostatic shield structure is realized.

  Next, a procedure for creating the planar winding portion 31 will be described with reference to FIGS.

  FIG. 4 is an explanatory diagram showing the coating removal process. First, preparation work for starting winding of the covered electric wire will be described. In this preparation stage, as shown in FIG. 4, two portions on the covered electric wire 30 are irradiated with a laser beam to melt and remove the covering to form the conductor exposed portion 32 and the conductor exposed portion 33. . On the other hand, as shown in FIG. 5, on the ferrite core 5 and the detection circuit board 6 side, the work of depositing the build-up solder 34, 35, 36 is performed. Here, the position where the build-up solder 34 is attached is the winding start end of the covered wire 30, the position where the build-up solder 35 is attached is the winding end of the covered wire 30, and the position where the build-up solder 36 is attached is the terminal on the detection circuit board 6. It corresponds to the pad 61. The terminal pad 61 functions as a GND pattern. The ferrite core 5 has a thin cylindrical shape having an end surface 5a and a core peripheral surface 5b, and a metal vapor deposition film is formed on the core end surface 5a and the core peripheral surface 5b. Overlay solders 34 and 35 are attached to this metal vapor deposition film.

  Subsequently, as shown in FIG. 6, the exposed solder portion 32 on the covered electric wire 30 is joined to the build-up solder 34 on the core end surface 5a of the ferrite core 5 by laser beam irradiation, whereby the joining solder 34a is joined. The winding start end of the covered electric wire 30 is electrically connected to the core end surface of the ferrite core 5.

  Subsequently, as shown in FIG. 7, the conductor exposed portion 33 on the covered electric wire 30 is positioned on the overlay solder 36 on the detection circuit substrate 6 by winding the covered electric wire 30 around the detection circuit substrate 6 for one turn. By irradiating this with a laser beam, the joining solder 36a is formed. As described above, since the terminal pad 61 to which the overlay solder 36 is attached functions as a GND pattern, the covered wire 30 is grounded to the GND pattern at the solder joint portion 36a.

  By the way, the terminal pad 62 on the detection circuit board 6 is on the side opposite to GND and directly connected to the oscillation circuit. As shown in FIG. 6, after the covered electric wire 30 is fixed to the core end surface 5 a by the bonding solder 34, the covered electric wire 30 starts to be wound from the board edge on the terminal pad 62 side. This is because the most desired part for noise protection is the “detection coil lead wire” of the “spool to the oscillation circuit”, and it is desired to wind around this part without any gap as much as possible. The positioning property when winding the covered wire 30 while hooking it on the edge of the substrate 6 is such that the hooking portion is flat, and such a starting direction is selected.

  The reason why the covered electric wire 30 is joined at the terminal pad 61 is that there is a possibility of short circuit between the covered electric wire 30 and the detection circuit board 6 (the covering of the covered electric wire 30 is peeled off with a laser or the like, but the peeling length is generated by several millimeters) This is because of countermeasures against this. Specifically, the coil terminal pin 39 connected to the back side of the terminal pad 61 is a GND terminal. Even if the coil terminal pin 39 and the covered electric wire 30 are short-circuited, both are at the GND potential and the circuit. This is because there is no trouble in operation.

  Subsequently, as shown in FIG. 8, the covered electric wire 30 fixed to the detection circuit board 6 with the bonding solder 36a is pulled up to the shoulder 38 which is the upper end of the wide part 6a of the detection circuit board 6 in the figure, and then As shown in FIG. 9, the covered electric wire 30 is rolled down in order from the top to the bottom. As shown in FIGS. 8 and 9, the covered electric wire 30 is pulled up from the joint solder 36a to the shoulder portion 38, and then is wound down downward. This is because we want to make only “layer”. The reason is that the clearance between the coil case 1 and the detection circuit board 6 is quite small, so if two or three windings are wound, the winding shield layer may interfere when inserted into the coil case 1. Because there is.

  Although a method of winding up sequentially from the bottom to the top is also conceivable, as shown in FIG. 9, the coil terminal pins 39 and 40 are swelled due to coil wire entanglement and solder. For this reason, when the covered electric wire 30 is wound around this portion, there is a possibility that it will be difficult to wind it at a uniform pitch by sliding down due to the inclination of the built-up portion. Actually, when winding up in order from the bottom to the top, as shown by arrows A and B in FIG. 9, the winding is shifted uniformly along the slope from the top of the mountain toward the bottom, so that the winding is performed uniformly. It was relatively difficult. On the other hand, as shown in FIG. 9 and FIG. 10, when winding down sequentially from top to bottom, it was relatively easy to wind at a uniform pitch.

  Thereafter, as shown in FIG. 10, the planar winding portion 31 is formed by winding the covered wire 30 around the wide portion 6 a while sequentially winding the covered wire 30 by one layer from the top to the bottom. Since the planar winding portion 31 has a layered structure of a conductor, it is effectively grounded as an electrostatic shield member by being grounded to the GND pattern at the bonding solder 36a. And the planar winding part 31 formed in this way is insulated by insulating coating to the direction of an adjacent covered electric wire, ie, the direction crossing a covered electric wire, and an electric current does not flow. Then, even if the high frequency magnetic field generated from the detection coil 4 crosses the planar winding portion 31 and an eddy current electromotive force is generated, the eddy current does not flow in the direction crossing the winding, so that eddy current loss hardly occurs. This avoids harming the characteristics of the proximity sensor.

  Finally, as shown in FIGS. 11 and 12, the covered electric wire 30 is irradiated with a laser beam to form a conductor exposed portion 43, which is positioned on the built-up solder 35 on the core end surface 5a. If the exposed conductor portion 43 is bonded to the core end surface 5a by irradiation, the coated electric wire constituting the shield layer at two locations on the core end surface 5a, that is, the bonding solder 34a and the bonding solder 35a, as shown in FIG. Electrically connected to the core. Moreover, since the covered wire 30 is electrically connected to the GND potential at the terminal pad 61, the potential of the metal vapor deposition film of the ferrite core 5 is also stabilized at the GND potential.

  After that, as shown in FIG. 12, if the covered electric wire 30 following the conductor exposed portion 43 is cut, the surface winding is formed by densely winding the covered electric wire around the wide portion 6 a of the detection circuit board 6. When the part 31 is completed and connected to the GND potential, the electrostatic shield structure is completed. In addition, at this time, since the covered wire 30 is also connected to the ferrite core 5 at two locations, the potential of the metal vapor deposition film of the ferrite core 5 also becomes the GND potential, which contributes to the stabilization of the operation. The joint between the coated electric wire 30 and the metal vapor deposition film of the ferrite core 5 may be disconnected due to stress applied during the injection of the primary casting resin 29, during curing, and during expansion and contraction after curing. Then, since the connection is made at two places, the effect of the electrostatic shield by the metal vapor deposition film is maintained even if the connection at one place is broken.

  In addition, since the operation of winding the coated electric wire around the wide portion 6a of the detection circuit board 6 is easy to automate using a coil winding machine or the like, the electrostatic shield structure in this type of proximity sensor is inexpensive. Can be provided.

  Next, FIG. 13 shows an example of an electric wire that can be applied to the shield structure with windings according to the present invention. FIG. 2A shows a single-layer covered electric wire, FIG. 2B shows a two-layer covered electric wire (No. 1), FIG. 2C shows a two-layer covered electric wire (No. 2), and FIG.

  As shown in FIG. 2A, the single-layer covered electric wire has a single copper wire 44 and a polyurethane film 45 serving as conductors. This covered electric wire can also be used as a winding of the detection coil in the above-described proximity sensor embodiment. The approximate thickness of the polyurethane film is 0.01 mm, and the outer diameter of the entire coated wire is 0.02 mm to 0.60 mm. Such a one-layer covered electric wire is called a coil wire widely used in general. Used for relay coils, transformers, small motors, communication coils, etc. Versatile and very cheap. However, when it is wound directly on the substrate, it may be damaged at the edge of the substrate. For this reason, it is preferable to wind the wire after covering the edge of the substrate with an insulating tape or the like to form a rounded shape. Alternatively, an insulating layer may be provided on the surface of the substrate in advance. As the insulating layer, silicon potting, a cylindrical resin member, a heat shrinkable tube, or the like can be used.

  The two-layer covered electric wire (No. 1) shown in FIG. 2B has a copper single wire 46, a polyurethane first layer film 47, and a polyester second layer film 48 as conductors. Both the first layer coating 47 and the second layer coating 48 are extrusion coating. When the thinnest one is selected, the conductor diameter is 0.11 mm, and the outer diameter of the polyester film is about 0.18 mm. When the conductor diameter is 0.11 mm, the approximate thickness of each film is about 0.01 mm for the polyurethane film and about 0.025 mm for the polyester film.

  Characteristically, it is excellent in processing resistance due to the two-layer insulation film, and has high insulation. The insulation resistance is somewhat lower than that of the three-layer insulation film, but space efficiency is good because the outer skin diameter is small. The material cost is lower than that.

  The two-layer covered electric wire (No. 2) in FIG. 2C includes a copper single wire 49 serving as a conductor, a polyurethane first layer film 50, and a nylon second layer film 51. The nylon coating of the second layer is obtained by baking nylon resin. The outer diameter is about 0.02 mm to 0.55 mm. The approximate thickness of each coating is about 0.01 mm for the polyurethane coating and about 0.005 mm for the nylon coating.

  As a feature, it is a generally used coil wire, and the material cost is low, and it can be said that it is a coated electric wire that is generally excellent in processing resistance and deterioration characteristics. However, it may not be able to withstand the edges if it is wound directly on the substrate. In that case, it would have to be wound from above the edge with insulating tape or the like.

  The three-layer covered electric wire shown in FIG. 4D includes a copper single wire 52 serving as a conductor, a polyurethane first layer film 53, a polyester second layer film 54, and a polyamide third layer film 55. Have. A conductor diameter of 0.11 mm and a polyamide film outer diameter of 0.24 mm are used. When the conductor diameter is 0.11 mm, the approximate thickness of each film is about 0.01 mm for the polyurethane film, 0.028 mm for the polyester film, and about 0.028 mm for the polyamide film.

  Characteristically, since it is a three-layer insulating film, it is strong against the edge of the substrate and the insulation resistance is sufficiently maintained.

According to the above embodiment, the following effects can be obtained.
(1) Since the shield part can be formed of a covered electric wire with a low member cost, a significant cost reduction is expected.
(2) Since the shielded portion is formed by winding the covered electric wire around the circuit board, each type of size can be handled with one type of covered electric wire. Therefore, it is not necessary to prepare a shield member for each product type, and member management becomes easy.
(3) Since the shielded portion is formed by winding the covered electric wire around the circuit board, the assembly can be easily automated using a winding machine.
(4) A lead wire or copper foil for joining the coil core metal deposition part and the GND of the circuit board is not necessary, and the cost of the member can be reduced.
(5) The electrical joining of the shield part to the circuit board GND can be easily automated.
(6) The electrical joining of the coil core metal deposition part to the circuit board GND can be easily automated.
(7) Since the covered electric wire is wound around the electronic component mounted on the circuit board, the electronic component is protected from the outside. Therefore, the stress of the casting resin applied to the electronic component can be alleviated, and the electronic component can be peeled off and cracked.
(8) Since the same wire as the detection coil and the shield member can be used in the case where the detection coil is shared with the doubled wire of the detection coil, the members can be aggregated, and inventory management and cost reduction can be achieved.
(9) When the same material is used in common with the detection coil, it is possible to use the same equipment for the detection coil winding process and the shield winding process, thereby reducing the equipment cost and the number of processes. It is done.
(10) Since it is possible to configure a shield part fitted to a circuit board or electronic component for winding a covered electric wire, it is not necessary to provide an extra space in advance as compared with the conventional method of winding with a film with copper foil. Is excellent.

  By the way, a detection circuit board provided with a detection circuit, a core, and a detection coil are integrated, and a detection circuit board that does not include an output circuit is particularly called a detection end module of a proximity sensor. If a substrate with an output circuit is prepared separately from the detection circuit substrate and a plurality of types of detection end modules and output circuit substrates are prepared, many types of proximity sensor devices can be manufactured by combining them. . The detection end module can be distributed alone as an intermediate product of the proximity sensor device. If a coated electric wire is wrapped around the detection circuit board of the detection end module to form an electrostatic shield layer, the shield layer is almost in close contact with the detection circuit board and integrated. The module volume is increased only slightly, and the shield layer is less likely to break during handling. Accordingly, the detection end module can be easily handled as an intermediate product.

  Next, a circuit block diagram of a photoelectric sensor to which the present invention is applied is shown in FIG. The light emitting / receiving system of the photoelectric sensor includes a light projecting element 201 configured by an LED, a light receiving element 202 configured by a photodiode, a light projecting circuit unit 203 that emits light from the light projecting element 201, and a current of the light receiving element 202. And a light receiving circuit unit 204 that converts the output signal into a voltage signal and amplifies it. In the present embodiment, the light receiving circuit unit 204 corresponds to the detection circuit of the present invention.

  The central processing circuit 205 is constituted by an ASIC, controls the light projecting circuit unit 203 so that the light projecting element 201 is pulse-lit at a predetermined period, and outputs an output signal from the light receiving circuit unit 204 in synchronization with the lighting timing of the light projecting element 201. (Light reception signal) is acquired. Further, the central processing circuit 205 has a threshold value for the light reception signal, and determines that it is in the light incident state if a condition such that the magnitude of the light reception signal continuously exceeds the threshold value a predetermined number of times is satisfied. The threshold value can be adjusted by the sensitivity volume 206. The indicator lamp unit 207 includes two indicator lamps, an operation indicator lamp and a stability indicator lamp. The operation indicator light is turned on when it is determined that the light is incident. The stability indicator lamp is turned on when a light receiving signal larger than a threshold value by a certain rate is obtained. The output circuit unit 208 converts the discrimination result signal into an electrical signal having a predetermined specification and outputs it to the outside. The power supply circuit unit 209 receives a DC power supply input in a predetermined voltage range from the outside, converts the voltage into a voltage required inside the sensor, and supplies power to each circuit unit.

  In this embodiment, the covered electric wire 217 is wound around the light projecting element 201, the light receiving element 202, the light projecting circuit unit 203, the light receiving circuit unit 204, the central processing circuit 205, the output circuit unit 208, and the power supply circuit unit 209. Electrostatic shielded. The target of the electrostatic shield can be limited to the light receiving circuit unit 204 at least.

  A partial cross-sectional perspective view of the photoelectric sensor assembly with the case removed is shown in FIG. In this figure, the optical holder 210 is shown in cross section with the upper half removed. In the figure, a substrate holder 211 is made of resin and holds a main circuit substrate 212. 14 is mounted on the main circuit board 212, except for the light projecting element 201 and the light receiving element 202. As described above, the light receiving circuit unit 204 that is a detection circuit and other circuit units are provided on the main circuit board 212, but the main circuit board 212 corresponds to the detection circuit board in relation to the present invention. Signals between the light projecting element 201 and the light receiving element 202 and the main circuit board 212 are transmitted via the light projecting / receiving element substrate 213. In addition, in the figure, 214 is a light projecting lens, 215 is a light receiving lens, 216 is a lens cover, 217 is a covered electric wire, 218 is a connecting portion, and 207a and 207b are indicator lamps constituting an indicator lamp portion.

  FIG. 16 shows the state of the photoelectric sensor assembly as seen from a different angle from FIG. 15 when the covered electric wire has been wound. A region indicated by reference numeral 219 is a winding shield region. As is apparent from the figure, the covered electric wire 217 is also wound around the optical holder 210 containing the light receiving element 202. The terminal end of the covered electric wire 217 is bonded and fixed to the optical holder 210. Note that a locking portion may be provided in the optical holder 210, and the covered electric wire 217 may be fixed by being hooked there.

  A state in which the photoelectric sensor assembly is housed in the case 220 is shown in FIG. In this example, the case 220 has a cross-sectional display. The material of the case 220 is resin or metal. The case 220 is provided with a hole 221 for operating the sensitivity volume 206. A relay member (not shown) for transmitting the rotation of the driver held by the operator to the sensitivity volume 206 is fitted in the hole 221. The case 220 is provided with a hole 222 for visually recognizing the indicator lamps 207a and 207b. A transparent window member (not shown) is fitted into the hole 222.

  The ridges on the side surface of the substrate holder 211 abut on the inner surface of the case 220. The substrate holder 211 is not exactly a half cylinder, but has a C-shaped cylindrical section having an angle of more than 180 degrees around the central axis. Therefore, when the substrate holder 211 is inserted into the case 220, the case 220 does not rattle. Further, a groove is provided on the lower surface of the substrate holder 211 in parallel with the central axis. When this groove fits with the convex portion on the inner surface of the case, the rotation of the substrate holder 211 with respect to the case 220 is prevented. With such a structure, the substrate holder 211 can be positioned with respect to the case 220 simply by being inserted into the case 220 from the front of the case 220. Further, according to the shape of the substrate holder 211, it is substantially half-cylindrical, and there are few irregular parts of the shape, so that it is easy to align and wind the covered electric wire 217. If a component is mounted only on the surface on the side of the substrate holder 211 in the portion around which the covered electric wire 217 of the main circuit board 212 is wound, the covered electric wire 217 is formed on the surface of the main circuit board 212 on the side in contact with the covered electric wire 217. Therefore, it becomes easier to align and wind the covered wire 217, and the possibility of short circuit between the covered wire 217 and the circuit is further reduced. This photoelectric sensor further has a cap structure at the rear end of the case and a cable drawing structure, but illustration and description thereof are omitted.

It is a disassembled perspective view of a proximity sensor. It is a longitudinal cross-sectional view of a proximity sensor. It is a partial cross section perspective view of a proximity sensor. It is explanatory drawing which shows a coating | coated removal process. It is explanatory drawing which shows a solder adhesion process. It is explanatory drawing which shows the joining process to the core at the beginning of winding. It is explanatory drawing which shows the joining process to the board | substrate at the time of 1 turn winding. It is explanatory drawing which shows the transfer process to a board | substrate upper end. It is explanatory drawing which shows an unwinding start process. It is explanatory drawing which shows an unwinding completion process. It is explanatory drawing which shows the coating removal process of a winding end end. It is explanatory drawing which shows the joining process to the core at the time of winding end. It is a figure which shows the example of an applicable electric wire. It is a circuit block diagram of a photoelectric sensor. It is a partially broken perspective view of the photoelectric sensor assembly which removed the case. It is a perspective view of the photoelectric sensor assembly which shows the winding end state of a covered electric wire. It is a partially broken perspective view which shows the state which accommodated the photoelectric sensor assembly in the case.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Coil case 2 Mask conductor 3 Spool 4 Detection coil 5 Ferrite core 6 Detection circuit board 7 Harness 8 Output circuit board 9 Output circuit IC
DESCRIPTION OF SYMBOLS 10 Light emitting diode 11 Terminal pad 12 Rear-end part 13 Outer shell case 14 Operation | movement display window 15 End plug 16 Slit 17 Inlet 18 Exhaust port 19 Crevice part 20 Code protector 21 Electrical cord 22 Outer skin 23, 24 Core wire 25, 26 Conductor 27 1 Next casting resin 28 Sealing resin 29 Secondary casting resin 30 Coated wire 31 Sheet winding part 32, 33 Conductor exposed part 34, 35, 36 Overlay solder 37 Detection circuit IC
38 Shoulder 39, 40 Coil terminal pin 34a, 35a, 36a Bonding solder 44 Conductor 45 Coating 46 Conductor 47 First layer coating 48 Second layer coating 49 Conductor 50 First layer coating 51 Second layer coating 52 Conductor 53 First layer Film 54 Second layer film 55 Third layer film 61, 62 Terminal pad 100 Proximity sensor 200 Photoelectric sensor 201 Light emitting element 202 Light receiving element 203 Light emitting circuit part 204 Light receiving circuit part 205 Central processing part 206 Sensitivity volume 207 Indicator lamp part 208 Output circuit unit 209 Power supply circuit unit 210 Optical holder 211 Substrate holder 212 Main circuit board 213 Light emitting / receiving element substrate 214 Light projecting lens 215 Light receiving lens 216 Lens cover 217 Covered wire 218 Connection part 219 Winding shield part 220 Case 221 Hole 222 Hole

Claims (5)

Including a detection coil having a core and a detection circuit board on which electronic components constituting the detection circuit are mounted;
  Around the detection circuit board, a covered electric wire is wound in a planar shape so as to be in direct contact with the mounted electronic component,
  A metal film for electrostatically shielding the detection coil is provided on the outer surface of the core,
Both ends of the covered electric wire are electrically connected to the metal film of the core, and are electrically connected to the ground pattern of the detection circuit board at the intermediate portion thereof.
Accordingly, the proximity sensor device is characterized in that the detection circuit board is electrostatically shielded by the covered electric wire and the core is grounded. The proximity sensor device according to claim 1, wherein the covered electric wire is wound spirally and in a single layer. The sensing circuit proximity sensor device according to claim 1 or 2, characterized in, that comprises an oscillation circuit for detection coil and the resonant element. The proximity sensor device according to claim 1 , wherein the covering strength of the covered electric wire used for shielding is higher than the covering strength of the covered electric wire used as a winding of the detection coil. 5. The proximity sensor device according to claim 1 , wherein the covered electric wire used for the shield and the covered electric wire used as the winding of the detection coil are of the same type.

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