JP2006253070A - Sealing structure, sealing method, proximity sensor and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing structure allowing a sealing process in an opening of a case body for inserting and arranging a wiring member therein to be easily and efficiently carried out without increasing the size of a product, and capable of keeping high junction reliability in a solder junction part. <P>SOLUTION: This proximity sensor is provided with: a resin case 112 being the case body having the opening 113; an output circuit board 131 inserted and arranged in the opening 113 and being the wiring member having electrodes 132 for solder junction outside the resin case 112; a flux-coated layer 170 for closing a space between the inside wall surface of the opening 131 and the output circuit board 131; terminals 151 of a cord 150 for external connection jointed to the electrodes 132 for solder junction; and a secondary casting resin layer 180 covering the flux-coated layer 170 inside the resin case 112 and fixed to the resin case 112. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a sealing structure and a sealing method for sealing an opening provided in a case body such as an electronic device, and more specifically, a wiring member so as to pass through the opening provided in the case body. The present invention relates to a sealing structure and a sealing method in the opening portion of an electronic device or the like in which is disposed. The present invention also relates to a proximity sensor employing the sealing structure and the sealing method and a method for manufacturing the proximity sensor.

  In general, in an electronic device, a sealing structure is employed for the purpose of preventing moisture and oil from entering the case body in order to maintain high reliability and ensure a long product life. Especially in sensor devices such as proximity sensors and distance sensors, the surrounding environment where the sensor device is installed is often very severe, and it is necessary to adopt a structure with excellent environmental resistance. It is necessary to seal the case body constituting the outer shell of the product in an airtight and watertight manner.

  When this sealing structure is adopted, there is a problem in sealing processing at a site that secures electrical connection to the outside of the case body of an electronic circuit constituted by electronic components arranged inside the case body. Usually, in the above portion, an opening is provided in a part of the case body, and a wiring member (for example, a lead wire, a conductive plate, a circuit board, etc.) is disposed so as to be inserted through the opening. Therefore, a configuration in which a gap between the inner wall surface of the case body constituting the opening and the wiring member is sealed with a resin member or the like is employed for sealing at this portion.

  However, applying and curing the molten resin directly in the gap between the case body and the wiring member, from the viewpoint of fluidity of the molten resin, causes problems such as dripping out of the resin and heat shrinkage during curing. Sufficient sealing performance is not always exhibited. Therefore, in general, the gap is temporarily sealed with some member, and a molten resin is attached on the outside or the inside of the case body so as to cover the temporary sealing member. In many cases, the main sealing is performed.

As a document disclosing this kind of sealing structure and sealing method, there is, for example, JP-A-6-28958 (Patent Document 1). In the sealing method disclosed in Patent Document 1, a circuit board is disposed inside a case body, and a separator provided with an opening through which the circuit board can be inserted is formed in a gap formed by the case body and the circuit board. Press fit, close the gap with the separator, and then attach molten resin to cover the contact part between the separator and the case body and the contact part between the separator and the circuit board at the part outside the separator. By making it harden | cure, the sealing structure in the said site | part is implement | achieved.
JP-A-6-28958

  However, the sealing structure disclosed in Patent Document 1 requires that the separator and the circuit board are in close contact with each other in the step of applying the molten resin, and the adhesion between these members is insufficient. In this case, the molten resin leaks into the case body from the gap, and a sufficient sealing effect cannot be obtained. Further, when the separator is manufactured using a hard material, it is very difficult to manage the size of the separator with high accuracy to the extent that such adhesion is surely satisfied. On the other hand, even when the separator is manufactured using a soft material, the work of press-fitting the separator made of the soft material into the circuit board and the case body is very complicated, and the workability is remarkably impaired. End up.

  From such a viewpoint, a sealing method using an adhesive as a material for temporarily sealing the opening provided in the case body before the main sealing with the resin member is known. In this sealing method, a wiring member is inserted and arranged in an opening provided in the case body, and an adhesive is applied to a gap generated between the inner wall surface of the case body and the wiring member constituting the opening, and cured. Thus, the opening is temporarily sealed, and then a molten resin is attached and cured outside the case body so as to cover the adhesive layer, thereby realizing a sealing structure in the opening.

  However, when this sealing method is adopted, the adhesive applied to the gap sucks up the surface of the wiring member, and the solder bonding electrode to which the terminal for external connection provided on the surface of the wiring member is bonded It becomes a thin film and adheres to the surface of the solder, and causes a bonding failure in the solder joint portion in a subsequent soldering process. In order to avoid this, it is conceivable to increase the distance between the case body in which the opening is formed and the solder bonding electrode of the wiring member, but this leads to an increase in the size of the product. It is hard to say that it is a preferable solution. Moreover, when the said sealing method is employ | adopted, the process of hardening an adhesive agent is needed separately, and the deterioration of production efficiency will also be caused.

  Therefore, the present invention has been made to solve the above-mentioned problems, and it is easy and efficient to perform a sealing process at the opening of the case body in which the wiring member is inserted and arranged without causing an increase in the size of the product. For the purpose of providing a sealing structure and a sealing method that can be performed in a continuous manner and that can maintain high bonding reliability at the solder joint, and the sealing structure and the sealing method are also employed An object of the present invention is to provide a proximity sensor and a manufacturing method thereof.

  The sealing structure according to the present invention includes a case body having an opening, a wiring member inserted and disposed in the opening, and having a solder bonding electrode outside the case body, an inner wall surface of the opening, and the wiring A flux coating layer that closes a gap between the member, an external connection terminal joined to the solder joining electrode, and covers the flux coating layer at least inside or outside the case body; and And a resin sealing layer fixed to the case body.

  In the sealing structure according to the present invention, the peripheral edge of the case body constituting the opening protrudes toward at least one of the outer side and the inner side of the case body and along the wiring member. It is preferable that an extending wall portion is provided.

  Moreover, in the sealing structure based on the said invention, the said resin sealing layer is a solder layer located between the said electrode for solder joining, the said terminal for external connection, and these on the outer side of the said case body It may be an outer resin sealing layer provided so as to cover the solder joint portion including.

  In the sealing structure according to the present invention, the resin sealing layer is provided inside the case body so as to embed the inner space of the case body over substantially the entire region. It may be a stop layer.

  Furthermore, in the sealing structure based on the said invention, the said wiring member may be a circuit board by which the said electrode for solder joining was formed in the main surface.

  A proximity sensor according to the present invention is a proximity sensor having any one of the above-described sealing structures, the oscillation circuit being disposed inside the case body and including a detection coil as a resonance circuit element, and the case body And an output circuit that generates an output signal based on the oscillation state of the oscillation circuit. The wiring member is a member that electrically connects the output circuit and the solder bonding electrode. Is.

The sealing method based on this invention comprises the following processes.
(A) A positioning step in which a wiring member including a solder bonding electrode is inserted into the opening of the case body, and the solder bonding electrode is positioned outside the case body.
(B) Flux application that forms a flux application layer that temporarily seals the opening by applying flux to the wiring member so as to close the gap between the inner wall surface of the opening and the wiring member. Layer formation process.
(C) A joining step in which a terminal for external connection is joined to the solder joining electrode of the wiring member on which the flux coating layer is formed by soldering.
(D) At least either inside or outside of the case body, the molten resin is attached to the case body so as to cover the flux coating layer, and then the molten resin is cured, so that the opening is fully sealed. A resin sealing layer forming step of forming a resin sealing layer to be stopped.

  In the sealing method according to the present invention, when the bonding step is performed prior to the resin sealing layer forming step, the resin sealing layer forming step is performed outside the case body. By adhering the molten resin to the case body so as to cover a solder bonding portion including a solder bonding electrode, the external connection terminal, and a solder layer positioned between them, and then curing the molten resin An outer resin sealing layer forming step of forming an outer resin sealing layer for main sealing the opening may be included.

  Further, in the sealing method according to the present invention, when the resin sealing layer forming step is performed prior to the joining step, the resin sealing layer forming step is performed inside the case body. An inner resin sealing layer that seals the openings by attaching the molten resin to the case body so as to embed the inner space of the case body substantially over the entire region, and then curing the molten resin. An inner resin sealing layer forming step of forming may be included.

  Furthermore, in the sealing method according to the present invention, the wiring member may be a circuit board in which the solder bonding electrode is formed on the main surface.

  A method of manufacturing a proximity sensor according to the present invention uses any of the above-described sealing methods, an oscillation circuit disposed inside the case body and including a detection coil as a resonance circuit element, and the case body And an output circuit that generates an output signal based on the oscillation state of the oscillation circuit. In the proximity sensor, the wiring member is a member that electrically connects the output circuit and the solder bonding electrode.

  According to the present invention, since the gap formed between the inner wall surface of the opening of the case body and the wiring member is blocked in advance by the flux coating layer, the resin for main sealing of the opening of the case body When the sealing layer is formed, the flow of the molten resin attached to the case body is blocked by the flux coating layer, and the dripping or leakage of the molten resin through the gap is prevented. In addition, since the member that temporarily seals the gap is flux, even if this flux adheres to the solder bonding electrode of the wiring member, it does not adversely affect the bonding reliability at the solder bonding portion. As a result, soldering of terminals for external connection is promoted. That is, by selecting a flux as a member for temporarily sealing the gap, it is possible to achieve both the reliable temporary sealing of the gap and the elimination of adverse effects on the solder joint.

  Therefore, the sealing process at the opening of the case body through which the wiring member is inserted and arranged can be easily and efficiently performed without increasing the size of the product, and the bonding reliability at the solder bonding portion. Can be kept high. Further, by applying such a sealing structure and sealing method to a proximity sensor and a manufacturing method thereof, a small and high-performance proximity sensor can be manufactured at low cost.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the embodiment described below, a case where the sealing structure and the sealing method according to the present invention are applied to a proximity sensor that detects the approach of an object will be described as an example.

(Embodiment 1)
FIG. 1 is a schematic cross-sectional view showing the structure of the proximity sensor according to Embodiment 1 of the present invention. FIG. 2 is an exploded perspective view showing the assembly structure of the proximity sensor shown in FIG. First, the structure of the proximity sensor in the present embodiment will be described with reference to FIG. 1 and FIG.

  As shown in FIGS. 1 and 2, the proximity sensor 100 </ b> A in the present embodiment has a substantially columnar outer shape, and has a cylindrical case body 110 and a front of the case body 110 inside the case body 110. The detection unit assembly 120 attached to the end mainly includes an output unit assembly 130 attached to the rear end of the case body 110 inside the case body 110. The detection unit assembly 120 includes a detection coil 121, a ferrite core 122, a coil case 123, a detection circuit board 124, a primary casting resin layer 125, and the like. Here, the primary casting resin layer 125 is used to fix the coil assembly including the detection coil 121 and the ferrite core 122 and the detection circuit board 124 connected to the coil assembly inside the coil case 123. It is a member and is a layer formed by filling molten resin in the coil case 123 and curing it. The output unit assembly 130 includes an output circuit board 131.

  The detection circuit board 124 of the detection unit assembly 120 attached to the front end of the case body 110 and the output circuit board 131 of the output part assembly 130 attached to the rear end of the case body 110 are connected by the connection member 140. Has been. In the proximity sensor 100A in the present embodiment, both the detection circuit board 124 and the output circuit board 131 are formed of a rigid wiring board, and the connection member 140 is formed of a flexible wiring board.

  Here, the rigid wiring board is a wiring board having high rigidity such as a glass-epoxy board, and is suitable for mounting electronic components. On the other hand, a flexible wiring board is a wiring board that is more flexible than a rigid wiring board. For example, a conductive pattern is bonded to the main surface of a base material made of polyimide resin with an adhesive or the like. It is a printed wiring board. Since this flexible wiring board is moderately flexible, it can be bent and folded freely, and as a wiring board that relays the connection between the conductive patterns of the rigid wiring boards that are spaced apart from each other. It is available.

  The case body 110 includes a metal case 111 and a resin case 112, and is configured by press-fitting the resin case 112 into the rear end of the metal case 111. A slit-like opening 113 is formed in the rear end surface of the resin case 112, and the rear end of the output circuit board 131 is inserted and disposed so as to penetrate the opening 113. That is, in proximity sensor 100A in the present embodiment, case body 110 is constituted by metal case 111 and resin case 112, and in opening 113 provided at the rear end of case body 110. An output circuit board 131 as a wiring member is inserted and arranged.

  The terminal of the external connection cord 150 is joined to the output circuit board 131 at a portion located outside the case body 110 by soldering. A cord protector 160 as an outer resin sealing layer is provided at the rear end of the case body 110 by insert molding so as to cover the solder joint between the output circuit board 131 and the external connection cord 150. The space inside the case body 110 is filled with a secondary casting resin layer 180 as an inner resin sealing layer. The detailed structure of the rear end portion of the case body 110 will be described later.

  The detection circuit board 124 is provided with an oscillation circuit having the detection coil 121 as a resonance circuit element, and a discrimination circuit that binarizes the oscillation amplitude of the oscillation circuit with a threshold value. For this reason, the proximity sensor 100A can detect the approach of the magnetic body by detecting the decrease in the oscillation amplitude of the oscillation circuit and the stop of the oscillation that occur as the magnetic body approaches the detection coil 121. It is. The output circuit board 131 is provided with an output circuit that converts the output of the discrimination circuit into a voltage output or a current output of a predetermined specification, and the output is led to the outside through the external connection cord 150. . Further, the output circuit board 131 is also provided with a power supply circuit that converts electric power introduced from the outside via the external connection cord 150 into a predetermined power supply specification and outputs it to the detection circuit board 124.

  FIG. 3 is an enlarged cross-sectional view of the proximity sensor shown in FIG. 1 in a region III. Next, with reference to FIG. 3, the sealing structure in the rear end part of the proximity sensor in this Embodiment is demonstrated in detail.

  As shown in FIG. 3, in the proximity sensor 100 </ b> A according to the present embodiment, as described above, the slit-shaped opening 113 is formed on the rear end surface of the resin case 112 constituting a part of the case body 110. An output circuit board 131 as a wiring member is inserted into the slit-shaped opening 113. In addition, a standing wall portion 114 that protrudes toward the outside of the case body 110 and extends along the main surface of the output circuit board 131 is provided at the peripheral portion of the resin case 112 constituting the slit-shaped opening 113. . Here, the shape of the opening surface of the opening 113 is slightly larger than the cross-sectional shape of the output circuit board 131, and the inner wall surface of the standing wall 114 that forms the opening 113 and the main surface of the output circuit board 131. A gap of a predetermined size is formed between the two. The standing wall 114 is provided over the entire periphery of the opening 113 so as to surround the slit-shaped opening 113.

  At the rear end surface of the resin case 112, when a secondary casting resin layer 180, which will be described later, is formed, a resin injection port 116 for injecting molten resin into the case body 110, and when the molten resin is injected An exhaust port 117 for exhausting air remaining in the space in the case body 110 is provided. In addition, a minute protrusion 118 is provided at a predetermined position on the side surface of the resin case 112 to increase the fixing force with a cord protector 160 described later.

  A flux coating layer 170 is formed in the gap formed between the inner wall surface of the standing wall 114 forming the opening 113 and the main surface of the output circuit board 131 so as to close the gap. Here, the flux is a liquid material used for soldering, and at the time of soldering, the oxide on the metal surface to be soldered is released and washed, and a thin film is formed on the metal surface. It is a soldering accelerator that prevents the metal surface from being oxidized and at the same time reduces the interfacial tension of the molten solder to improve the wettability of the molten solder. As a flux applied to the gap to form the flux coating layer 170, a rosin and / or rosin derivative as a main component, which is generally known, and these rosin and / or rosin derivative are isopropyl alcohol or the like. Uses rosin flux dissolved in organic solvents, synthetic resin flux such as epoxy resin and phenol resin, and synthetic resin flux such as isopropyl alcohol dissolved in water. Is possible.

  In the rosin-based flux, the viscosity can be adjusted by appropriately adjusting the blending ratio of the solid component composed of rosin and / or rosin derivative to the solvent. Moreover, also in the said synthetic resin type | system | group flux, it is possible to adjust the viscosity by adjusting suitably the mixture ratio with respect to the solvent of the solid component which consists of synthetic resins. Therefore, the viscosity of the flux can be adjusted to a desired viscosity according to the size of the gap, thereby preventing the flux from dripping after application.

  Although it is preferable to change the viscosity of the flux depending on the size of the gap to be applied, it is possible to effectively prevent dripping if it is about 0.1 Pa · s to 5.0 Pa · s. Moreover, in the flux after preparation, as a composition for realizing the viscosity in the above range, the weight ratio of the solid component is about 30 w% to about 90 w% in any of the rosin flux and the synthetic resin flux, It is desirable to adjust the weight ratio of the solvent and other additives to about 70 w% to about 10 w% according to this.

  On the main surface of the rear end portion of the output circuit board 131, a solder joint electrode 132 to which the terminal 151 of the external connection cord 150 is soldered is provided. The solder bonding electrode 132 is formed, for example, by attaching copper to the main surface of a base material made of glass-epoxy resin of a rigid wiring board and patterning the copper into a predetermined shape. In the proximity sensor 100A shown in the figure, solder bonding electrodes 132 are provided on both surfaces of the output circuit board 131, and the terminals 151 of the external connection cord 150 are connected to the solder bonding electrodes 132 on both surfaces of the output circuit board 131. Bonded by the solder layer 152.

  As described above, the code protector 160 is formed at the rear end of the case body 110. The cord protector 160 is formed by insert molding, and is formed by attaching a molten resin to the rear end portion of the case body 110 and curing it. The cord protector 160 is formed on the front end side so as to cover the surface on which the protrusion 118 of the resin case 112 is formed, and is formed on the rear end side up to a portion covering the covering cover of the external connection cord 150. ing. The cord protector 160 is fixed to the case body 110 so as to cover the flux application layer 170 outside the case body 110, and is connected to the solder bonding electrode 132 provided on the output circuit board 131 and the external connection. It is provided so as to cover the terminal 151 of the cord 150 and the solder layer 152 located between them.

  Furthermore, the space inside the case body 110 is filled with the secondary casting resin layer 180 as described above. The secondary casting resin layer 180 is formed by curing the molten resin injected from the resin injection port 116 provided on the rear end surface of the resin case 112 described above. It is fixed to the case body 110 so as to cover the flux application layer 170 and substantially fills the entire interior space of the case body 110. The secondary casting resin layer 180 is for main sealing the opening 113 temporarily sealed by the flux coating layer 170.

  FIG. 4 is a process diagram for explaining the manufacturing method of the proximity sensor in the present embodiment, and FIGS. 5, 6, 9 and 10 are schematic sectional views of the proximity sensor in each process of the manufacturing method. It is. 7 is a side view of the proximity sensor in the step shown in FIG. 6, and FIG. 8 is a rear view of the proximity sensor in the step shown in FIG. Hereinafter, a method for manufacturing the proximity sensor having the above-described configuration will be described in detail with reference to FIGS.

  First, as shown in FIG. 4, in step S101, the detection unit assembly 120 is assembled. Specifically, the detection coil 121, the ferrite core 122, the coil case 123, and a detection circuit board 124 on which an oscillation circuit or the like is formed by mounting necessary components are prepared, and the coil case 123 is filled with polyurethane resin, The assembly part in which the detection coil 121, the ferrite core 122, and the detection circuit board 124 are assembled is disposed therein, and these parts are integrated by curing the polyurethane resin to manufacture the detection unit assembly 120.

  Next, as shown in FIG. 4, the output part assembly 130 is assembled in step S102. Specifically, an output circuit board 131 on which an output circuit and the like are formed is manufactured by mounting necessary components on a rigid wiring board.

  Next, as shown in FIG. 4, in step S <b> 103, the detection circuit board 124 and the output circuit board 131 are connected by the connection member 140. Specifically, a flexible wiring board having a predetermined length is prepared as the connecting member 140, solder bonding electrodes provided at the rear end of the detection circuit board 124 and the front end of the output circuit board 131, and the prepared flexible wiring The conductor patterns located at both ends of the substrate are joined by soldering by thermocompression bonding.

  Next, as shown in FIG. 4, in step S <b> 104, the case body 110 is attached to an intermediate product including the detection unit assembly 120, the output unit assembly 130, and the connection member 140. Specifically, first, the case body 110 is manufactured by press-fitting the resin case 112 into the rear end portion of the metal case 111, and the end surface on the front end side of the intermediate product manufactured in step S103 faces downward. In this way, the product in production is made upright, and the case body 110 is fitted into the product in production in the upright state from above. At this time, the front end of the case body 110 is extrapolated with respect to the coil case 123, and the output circuit board 131 passes through the opening 113 provided in the rear end surface of the case body 110. As a result, as shown in FIG. 5, the solder bonding electrode 132 provided at the rear end portion of the output circuit board 131 is positioned outside the case body 110. As shown in FIG. 5, the resin case 112 has a pair of resin reservoirs 115 at its rear end, and a resin inlet 116 and an exhaust port 117 are formed at the base of the resin reservoir 115, respectively. Has been.

  Next, as shown in FIG. 4, in step S <b> 105, the gap between the inner wall surface of the opening 113 of the case body 110 and the output circuit board 131 is temporarily sealed with a flux application layer 170. Specifically, as shown in FIG. 6, from the outside of the case body 110 using the dispenser 200, a flux prepared to have an appropriate viscosity is applied to the inner wall surface of the opening 113 of the case body 110 and the output circuit board. Apply toward the gap with 131.

  Here, since the flux has appropriate fluidity, it enters between the standing wall portion 114 of the resin case 112 and the output circuit board 131 by capillary action, and the gap is blocked by the applied flux. become. Further, since the flux has an appropriate viscosity, after flowing so as to fill the gap, the flux is held in the gap by the viscosity and does not flow any more. Therefore, by applying an appropriate amount of flux according to the size of the gap, the gap is surely closed by the flux application layer 170 as shown in FIGS. At this time, as shown in the figure, the flux may be attached to the output circuit board 131 so that the flux coating layer 170 partially covers the solder bonding electrode 132 of the output circuit board 131.

  Next, as shown in FIG. 4, in step S106, the inside of the case body 110 is resin-sealed. Specifically, as shown in FIG. 9, molten resin is injected from a resin reservoir 115 (resin reservoir on the left side in the figure) in which the resin injection port 116 is provided at the root, and the case is discharged from the exhaust port 117. While the air remaining inside the body 110 is exhausted, the molten resin is injected until the molten resin reaches both the resin reservoirs 115. At this time, the presence of the flux coating layer 170 previously formed in step S105 described above prevents the molten resin from leaking from the gap between the opening 113 of the case body 110 and the output circuit board 131, and the case body. The space inside 110 is surely filled with the molten resin. Then, by heating or leaving for a predetermined time, the molten resin filled in the case body 110 is cured to form a secondary casting resin layer 180 that is an inner resin sealing layer. By the secondary casting resin layer 180 after the curing, the space inside the case body 110 is substantially embedded throughout the entire area without a gap, and the opening 113 is the secondary casting resin layer 180 after the curing. The main sealing is performed. As a result, intrusion of moisture and oil from the opening 113 into the case body 110 is prevented. In addition, as a resin material that can be used as the secondary casting resin layer 180, for example, an epoxy resin or a polyurethane resin can be used.

  Next, as shown in FIG. 4, in step S107, the resin reservoir 115 of the resin case 112 is removed. Specifically, the resin reservoir 115 of the resin case 112 is cut off from the remaining portion of the resin case 112 by cutting the portion indicated by the broken line A in FIG. In addition, since the resin injection port 116 and the exhaust port 117 provided in the resin case 112 are closed by the above-described secondary casting resin layer 180, moisture and oil from this portion enter the case body 110. Intrusion is also prevented.

  Next, as shown in FIG. 4, in step S108, the solder bonding electrode 132 of the output circuit board 131 and the terminal 151 of the external connection cord 150 are soldered. Specifically, as shown in FIG. 10, the coating material at the tip of the external connection cord 150 is peeled to expose the core wire, and the terminal 151 made of the exposed core wire is connected to the solder bonding electrode 132 of the output circuit board 131. The terminals 151 and the solder bonding electrodes 132 are bonded by bringing them close to each other and adhering molten solder. At this time, the solder spreads with good wettability by the action of the flux previously attached to the surface of the output circuit board 131, and the terminal 151 and the solder bonding electrode 132 are bonded in a good bonded state. Become.

  Next, as shown in FIG. 4, a cord protector 160 is formed at the rear end of the case body 110 in step S109. Specifically, the cord protector 160 is insert-molded by attaching a mold having a predetermined shape to the rear end portion of the case body 110 and injecting a molten resin into the mold to be cured. At this time, the formed cord protector 160 covers the solder joint portion including the terminal 151 of the external connection cord 150, the solder joint electrode 132 of the output circuit board 131, and the solder layer 152 positioned therebetween. At the same time, the cord protector 160 is fixed to the rear end portion of the case body 110 so that the flux coating layer 170 formed between the inner wall surface of the opening 113 of the case body 110 and the output circuit board 131 is covered. As described above, a sealing structure as shown in FIG. 3 is obtained.

  By adopting the structure and manufacturing method of the proximity sensor according to the present embodiment described above, the following effects can be obtained.

  First, since the gap formed between the inner wall surface of the opening 113 of the case body 110 and the output circuit board 131 is previously closed by the flux application layer 170, the opening of the case body 110 When forming the secondary casting resin layer 180 which is the inner resin sealing layer 113 for the main sealing of 113, the flow of the molten resin attached to the case body 110 is blocked by the flux application layer 170, and Leakage of the molten resin to the outside of the case body 110 through the gap is prevented. Further, since the member that temporarily seals the gap is flux, even if this flux adheres to the solder bonding electrode 132 of the output circuit board 131, it does not have any adverse effect on the bonding reliability at the solder bonding portion. Conversely, soldering of the terminal 151 of the external connection cord 150 is promoted. That is, by selecting a flux as a member for temporarily sealing the gap, it is possible to achieve both the reliable temporary sealing of the gap and the elimination of adverse effects on the solder joint.

  For this reason, since it becomes possible to arrange | position the said clearance gap and a solder junction part closely, a proximity sensor does not enlarge. Further, compared with the case of temporary sealing using an adhesive, when temporary sealing is performed using a flux, it is not necessary to pay attention so that the flux does not adhere to the solder bonding electrode 132, and the output circuit board 131 is The sealing process in the opening 113 of the case body 110 to be inserted and arranged can be performed easily and efficiently. Furthermore, the provisional sealing using the flux as in this embodiment eliminates the need for a curing step required for temporary sealing using an adhesive, thus greatly improving production efficiency. . Further, due to the action of the flux, it is possible to maintain high bonding reliability of the solder joint between the terminal 151 of the external connection cord 150 and the solder joint electrode 132 of the output circuit board 131. Therefore, the sealing process at the opening 113 of the case body 110 into which the output circuit board 131 is inserted and arranged can be easily and efficiently performed without causing an increase in the size of the proximity sensor. It becomes possible to maintain high joint reliability in the portion.

  Secondly, in the proximity sensor 100A according to the present embodiment, the upright wall 114 is provided at the peripheral edge of the case body 110 constituting the opening 113, so that the inner wall surface of the opening 113 of the case body 110 is provided. And the distance in the front-rear direction of the gap formed between the output circuit board 131 and the output circuit board 131 is ensured. For this reason, the distance in the front-rear direction of the flux application layer 170 that closes the gap also increases, and as a result, the distance between the outside and the inside of the case body 110 is greatly separated. Therefore, with this configuration, the temporary sealing of the opening 113 can be performed more reliably.

  The present inventor conducted a verification experiment as to whether or not temporary sealing of the opening of the case body into which the circuit board is actually inserted and arranged by flux is possible. In the following, an example of the verification experiment will be described.

  In the verification test, the distance between the inner wall surface of the opening 113 formed at the rear end of the case body 110 of the proximity sensor 100A and the output circuit board 131 (distances D1 and D2 shown in FIGS. 6 and 8). Was 0.15 mm, and the height of the standing wall 114 provided around the opening 113 (height H shown in FIG. 6) was 2.0 mm. Further, rosin-based flux was used as the flux used for temporary sealing, the weight ratio of the solid component of the flux composed of rosin and rosin derivative was 60 w%, and the weight ratio of the solvent and other additives was 40%. The viscosity of the flux prepared at this blending ratio was approximately 3.0 Pa · s.

  In this case, the flux applied to the gap does not sag inside the case body 110 and closes the gap, and is then temporarily sealed with the flux when the secondary casting resin layer 180 is formed thereafter. It was confirmed that the molten resin did not leak from the gap.

(Embodiment 2)
FIG. 11 is a schematic cross-sectional view showing the structure of the proximity sensor according to Embodiment 2 of the present invention. FIG. 12 is an enlarged cross-sectional view of the proximity sensor shown in FIG. 11 in the region XII. First, the structure of the proximity sensor in the present embodiment will be described with reference to FIG. 11 and FIG. In addition, the same code | symbol is attached | subjected in the figure about the part similar to the proximity sensor in the above-mentioned Embodiment 1, and the description is not repeated here.

  As shown in FIG. 11, the proximity sensor 100B in the present embodiment has substantially the same structure as that of the above-described embodiment, but has a configuration in that it does not have a secondary casting resin layer. It is different. That is, the proximity sensor 100B according to the present embodiment has a configuration in which the space inside the case body 110 is hollow-sealed, and includes the rear end portion of the detection circuit board 124, the connection member 140, and the output circuit board. Each front end portion of 131 is exposed inside case body 110. That is, the opening 113 of the case body 110 is fully sealed by the cord protector 160.

  FIG. 13 is a process diagram for explaining the manufacturing method of the proximity sensor in the present embodiment. Below, the manufacturing method of the proximity sensor in this Embodiment is demonstrated with reference to FIG. Note that the detailed description of the same steps as those of the proximity sensor manufacturing method according to the first embodiment will not be repeated here.

  When manufacturing the proximity sensor 100B according to the present embodiment, as shown in FIG. 13, the detection unit assembly 120 is assembled in step S201, and then the output unit assembly 130 is assembled in step S202. To do. Next, in step S203, the detection circuit board 124 and the output circuit board 131 are connected by the connection member 140. Subsequently, in step S204, the production including the detection unit assembly 120, the output unit assembly 130, and the connection member 140 is performed. The case body 110 is attached to the intermediate product. In step S <b> 205, the gap between the inner wall surface of the opening 113 of the case body 110 and the output circuit board 131 is temporarily sealed with the flux application layer 170. Each process so far is the same procedure as the manufacturing method of proximity sensor 100A in the above-mentioned first embodiment.

  Next, in step S206, the solder bonding electrode 132 of the output circuit board 131 and the terminal 151 of the external connection cord 150 are soldered. Subsequently, in step S207, the cord protector is attached to the rear end portion of the case body 110. 160 is formed. Thus, a sealing structure as shown in FIG. 12 is obtained.

  As described above, the manufacturing method of the proximity sensor in the present embodiment is different from the manufacturing method of the proximity sensor in the above-described first embodiment, and external connection is performed prior to the main sealing of the opening 113 of the case body 110. The soldering cord 150 is soldered.

  By adopting the proximity sensor structure and manufacturing method according to the present embodiment described above, the gap formed between the inner wall surface of the opening 113 of the case body 110 and the output circuit board 131 becomes a flux coating layer 170. Therefore, when the cord protector 160 that is the outer resin sealing layer for the main sealing of the opening 113 of the case body 110 is formed, the flow of the molten resin that adheres to the case body 110 Is blocked by the flux coating layer 170 and the dripping of the molten resin into the case body 110 through the gap is prevented. Further, since the member that temporarily seals the gap is flux, even if this flux adheres to the solder bonding electrode 132 of the output circuit board 131, it does not have any adverse effect on the bonding reliability at the solder bonding portion. Conversely, soldering of the terminal 151 of the external connection cord 150 is promoted. That is, by selecting a flux as a member for temporarily sealing the gap, it is possible to achieve both the reliable temporary sealing of the gap and the elimination of adverse effects on the solder joint.

  Therefore, as in the first embodiment, the sealing process at the opening 113 of the case body 110 into which the output circuit board 131 is inserted is easily and efficiently performed without causing an increase in the size of the proximity sensor. It becomes possible to perform this, and it becomes possible to maintain high joint reliability at the solder joint. Furthermore, since the circuit components disposed inside the case body 110 are not covered with the resin, bonding failure due to stress at the time of resin sealing or damage due to changes in the external environmental temperature during use occurs. It becomes difficult and it can be set as a highly reliable proximity sensor.

  In the sealing structure and the sealing method according to the embodiment of the present invention described above, the case where a circuit board made of a rigid wiring board is used as the wiring member has been described as an example. Is not to be done. The wiring member to which the sealing structure and the sealing method as in the present invention can be applied can be applied to various types such as a flexible wiring board, a wiring member composed only of a lead wire and a conductor plate.

  In the above-described embodiment, the case where a cord is used as the wiring means for external connection has been described as an example. However, the present invention naturally includes a case where an output terminal using a pin or the like is used. Its application is possible.

  Furthermore, in the above-described embodiment, the case where the sealing structure and the sealing method according to the present invention are applied to a proximity sensor has been described as an example. However, for other electronic devices (particularly sensor devices) Of course, it is also possible to apply.

  Thus, the above-described embodiments disclosed herein are illustrative in all respects and are not restrictive. The technical scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a schematic cross section which shows the structure of the proximity sensor in Embodiment 1 of this invention. It is a disassembled perspective view which shows the assembly structure of the proximity sensor in Embodiment 1 of this invention. It is an expanded sectional view of the area | region III shown in FIG. 1 of the proximity sensor in Embodiment 1 of this invention. It is process drawing for demonstrating the manufacturing method of the proximity sensor in Embodiment 1 of this invention. It is a schematic cross section in the manufacturing process of the proximity sensor in Embodiment 1 of this invention. It is a schematic cross section in the manufacturing process of the proximity sensor in Embodiment 1 of this invention. It is a side view in the manufacturing process shown in FIG. 6 of the proximity sensor in Embodiment 1 of this invention. It is a rear view in the manufacturing process shown in FIG. 6 of the proximity sensor in Embodiment 1 of this invention. It is a schematic cross section in the manufacturing process of the proximity sensor in Embodiment 1 of this invention. It is a schematic cross section in the manufacturing process of the proximity sensor in Embodiment 1 of this invention. It is a schematic cross section which shows the structure of the proximity sensor in Embodiment 2 of this invention. It is an expanded sectional view of the area | region XII shown in FIG. 11 of the proximity sensor in Embodiment 2 of this invention. It is process drawing for demonstrating the manufacturing method of the proximity sensor in Embodiment 2 of this invention.

Explanation of symbols

  100A, 100B Proximity sensor, 110 Case body, 111 Metal case, 112 Resin case, 113 Opening part, 114 Standing wall part, 116 Resin inlet, 117 Exhaust port, 118 Protruding part, 120 Detector assembly, 121 Detector coil, 122 Ferrite core, 123 coil case, 124 detection circuit board, 125 primary cast resin layer, 130 output assembly, 131 output circuit board, 132 solder joint electrode, 140 connecting member, 150 external connection cord, 151 terminal, 152 Solder layer, 160 code protector (outer resin sealing layer), 170 flux coating layer, 180 secondary casting resin layer (inner resin sealing layer), 200 dispenser.

Claims (11)

A case body having an opening;
A wiring member that is inserted into the opening and has a solder bonding electrode on the outside of the case body; and
A flux coating layer that closes a gap between the inner wall surface of the opening and the wiring member;
A terminal for external connection bonded to the solder bonding electrode;
A sealing structure comprising: a resin sealing layer that covers the flux application layer and is fixed to the case body at least either inside or outside the case body.   The standing wall part which protrudes toward the at least one of the outer side or the inner side of the said case body, and is extended along the said wiring member is provided in the peripheral part of the said case body which comprises the said opening part. The sealing structure described.   The resin sealing layer is provided on the outer side of the case body so as to cover a solder joint including the solder joint electrode, the external connection terminal, and a solder layer positioned therebetween. The sealing structure according to claim 1, comprising a sealing layer.   The said resin sealing layer consists of an inner side resin sealing layer provided so that the inner space of the said case body might be embedded over the whole region inside the said case body. Sealing structure.   5. The sealing structure according to claim 1, wherein the wiring member is a circuit board on which a solder bonding electrode is formed on a main surface. A proximity sensor comprising the sealing structure according to claim 1,
An oscillation circuit disposed inside the case body and including a detection coil as a resonant circuit element;
An output circuit disposed inside the case body and generating an output signal based on an oscillation state of the oscillation circuit;
The proximity sensor, wherein the wiring member is a member that electrically connects the output circuit and the solder bonding electrode. A positioning step of inserting and arranging a wiring member including a solder bonding electrode in the opening of the case body, and positioning the solder bonding electrode on the outside of the case body;
A flux coating layer forming step of forming a flux coating layer that temporarily seals the opening by applying flux to the wiring member so as to close a gap between the inner wall surface of the opening and the wiring member When,
A bonding step of bonding a terminal for external connection to the solder bonding electrode of the wiring member on which the flux coating layer is formed by soldering;
Resin that fully seals the opening by attaching a molten resin to the case body so as to cover the flux coating layer at least either inside or outside the case body, and then curing the molten resin A sealing method comprising: a resin sealing layer forming step of forming a sealing layer. Prior to the resin sealing layer forming step, the joining step is performed,
The resin sealing layer forming step includes the case body so as to cover a solder joint portion including the solder joint electrode, the external connection terminal, and a solder layer positioned therebetween, outside the case body. The method according to claim 7, further comprising an outer resin sealing layer forming step of forming an outer resin sealing layer for main sealing the opening by attaching the molten resin to the resin and then curing the molten resin. Sealing method. Prior to the joining step, the resin sealing layer forming step is performed,
In the resin sealing layer forming step, the molten resin is attached to the case body so as to embed substantially the entire internal space of the case body inside the case body, and then the molten resin is cured. The sealing method according to claim 7, further comprising: an inner resin sealing layer forming step of forming an inner resin sealing layer for main sealing the opening.   The sealing method according to claim 7, wherein the wiring member is a circuit board having the solder bonding electrode formed on a main surface. A method for manufacturing a proximity sensor using the sealing method according to any one of claims 7 to 10,
The proximity sensor is arranged inside the case body and includes an oscillation circuit including a detection coil as a resonance circuit element, and an output circuit arranged inside the case body and generating an output signal based on the oscillation state of the oscillation circuit And
The method of manufacturing a proximity sensor, wherein the wiring member is a member that electrically connects the output circuit and the solder bonding electrode.

Images