JP5666209B2 - Detection sensor - Google Patents

Description

  The present invention relates to a detection sensor for detecting a liquid, such as a leak detection sensor.

  Conventionally, in a liquid leakage detection sensor, for example, as shown in Patent Document 1, a housing is placed on an installation surface such as a floor surface, and a detection unit that detects liquid that has entered between the installation surface and the housing is provided. There is something to prepare. Such a detection sensor is mounted on a lower installation surface of a production apparatus or the like of a production line, for example, and it is possible to detect leakage of the production apparatus by detecting the presence or absence of water on the installation surface. Yes.

JP 2004-53560 A

  However, in the detection sensor as described above, if the leakage from the manufacturing apparatus adheres to the upper surface of the housing and remains as it is, the leakage that can be detected by the detection unit (leakage that enters between the installation surface and the housing). Since the amount of liquid) was small, it was difficult to detect stable liquid leakage.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide a detection sensor capable of stable liquid detection.

In order to solve the above-mentioned problem, the invention according to claim 1 is a detection sensor including a detection unit for detecting liquid that has entered between a lower surface of a housing placed on an installation surface and the installation surface. The upper surface of the housing is provided with an inclined surface that is inclined downward from the central portion toward the peripheral edge of the upper surface, and the inclined surface has a groove portion extending toward the peripheral edge of the upper surface of the housing. It is provided .

In this invention, the liquid adhering to the inclined surface on the upper surface of the housing flows toward the peripheral edge of the upper surface of the housing and adheres to the installation surface along the side surface of the housing. As a result, the liquid adhering to the upper surface of the housing can be easily infiltrated between the installation surface and the housing, so that stable liquid detection at the detection unit is possible. Moreover, in this invention, the liquid adhering to an inclined surface can be made to flow easily with an installation surface by the groove part provided in the inclined surface.

According to a second aspect of the present invention, in the detection sensor according to the first aspect, the housing has a cylindrical shape, and the inclined surface on the upper surface has a dome shape.
In this invention, since the inclined surface provided on the upper surface of the cylindrical housing forms a dome shape, the liquid adhering to the inclined surface can be suitably flowed to the installation surface, and as a result, more stable in the detection unit. Liquid detection is possible.

According to a third aspect of the present invention, in the detection sensor according to the first or second aspect, the inclined surface is continuously inclined from a center portion to a peripheral edge of the upper surface of the housing.
In this invention, since the inclined surface continuously inclines from the center portion to the peripheral edge of the upper surface of the housing, the liquid adhering to the inclined surface can be made to easily flow on the installation surface.

According to a fourth aspect of the present invention, in the detection sensor according to any one of the first to third aspects, a cable lead-out portion is formed on the side surface of the housing so as to project the cable to the outside of the housing. It is characterized by that.

  In this invention, since the cable lead-out portion protruding from the housing is formed on the side surface of the housing, the liquid adhering to the inclined surface can be made to flow more easily on the installation surface compared to the configuration in which the cable lead-out portion is formed on the top surface of the housing. Can do.

According to a fifth aspect of the present invention, in the detection sensor according to any one of the first to fourth aspects, a display portion is provided on the inclined surface.
In the present invention, since the display unit is provided on the inclined surface that is easy to flow down even if liquid leakage adheres, it is possible to suppress a decrease in the visibility of the display unit due to liquid leakage.

The invention according to claim 6, the detection sensor according to claim 1, wherein the housing includes a housing body having an opening for mounting the internal components on the top side, of the housing body A cover for watertightly closing the opening, wherein the inclined surface is constituted by the housing body and an upper surface of the cover, and the cover is fixed to the opening of the housing body by laser welding. To do.

  In this invention, since the inclined surface is composed of the housing body and the upper surface of the cover, the boundary portion between the opening of the housing body and the cover on the upper surface of the housing is located on the inclined surface, but by using laser welding, The cover can be easily welded to the opening of the housing body.

  Therefore, according to the above described invention, stable liquid detection becomes possible.

It is the schematic which shows an example of the use of the leak detection sensor of this embodiment. It is a perspective view of a leak detection sensor. It is a disassembled perspective view of a leak detection sensor. It is a top view of a leak detection sensor. It is a bottom view of a leak detection sensor. It is sectional drawing of a leak detection sensor. It is sectional drawing which cut the leak detection sensor so that a detection part might be passed. It is a perspective view of a cover. It is a schematic diagram for demonstrating the course of the light from a light projection element. It is a perspective view for demonstrating the laser welding method of a cable derivation | leading-out part and a cable. (A) (b) is a perspective view for demonstrating the laser welding of a cable derivation | leading-out part and a cable. The schematic diagram which shows a part of housing of another example.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings.
As shown in FIG. 1, the liquid leakage detection sensor 1 is attached to an installation surface P below the manufacturing apparatus D in the factory with bolts (not shown), and detects liquid leakage from the manufacturing apparatus D. It is. As shown in FIGS. 2, 3, 4, and 5, the leak detection sensor 1 includes a sensor main body 11, a base 12 interposed between the installation surface P and the sensor main body 11, and a sensor The main body part 11 is fixed to the installation surface P and has a holding member 13 that holds the base part 12.

  The sensor main body 11 includes a substantially bottomed cylindrical case 14 (housing main body), a cover 15 for closing the upper portion of the case 14 in a watertight manner, and a cable 16 led out from the case 14. The case 14, the cover 15, and the base portion 12 constitute a housing H. The case 14 is made of a fluororesin such as PFA (perfluoroalkoxyalkane) having heat resistance and chemical resistance, and has a cylindrical outer peripheral portion 21 and a bottom portion 22 that closes one end of the outer peripheral portion 21. The opening 14a (the end opposite to the bottom 22) of the outer peripheral portion 21 is closed by a substantially disc-shaped cover 15 (see FIG. 8), and this cover 15 also has heat resistance and chemical resistance. It consists of a fluororesin such as PFA.

  The cable 16 has a tube-shaped outer member 16a made of a fluororesin such as PFA having heat resistance and chemical resistance, and has a plurality of conductive wires (not shown) inside the outer member 16a. The cable 16 is electrically connected to a substrate 17 housed inside the case 14 and is led out of the case 14 from a distal end portion 23 a of the cable lead-out portion 23 formed in the case 14. ing. The substrate 17 accommodated in the case 14 is provided so that its plate surface is orthogonal to the height direction Z. Two light projecting elements 18 and two light receiving elements 19 are provided on the lower surface of the substrate 17 (see FIG. 7). Further, three LEDs 20 arranged in the left-right direction Y are provided on the upper surface of the substrate 17 (see FIGS. 6 and 7).

  A base 24 that protrudes in a substantially rectangular shape is formed at the rear end of the front-rear direction X of the outer peripheral portion 21 of the case 14. An end surface 24a in the front-rear direction X of the base 24 forms a plane orthogonal to the front-rear direction X, and the cable lead-out portion 23 that protrudes along the front-rear direction X is formed from the end surface 24a. The cable lead-out portion 23 has a cylindrical shape, and an inner peripheral portion thereof is an insertion hole 25 through which the cable 16 is inserted.

  The distal end portion 23a of the cable lead-out portion 23 has a tapered shape and a tapered shape. Specifically, the diameter of the insertion hole 25 of the cable lead-out portion 23 (the inner peripheral diameter of the cable lead-out portion 23) is formed to be constant over the entire axial direction of the cable lead-out portion 23 (see FIG. 6). ). Note that the axial direction of the cable lead-out portion 23 matches the penetrating direction of the insertion hole 25, and in the present embodiment also matches the front-rear direction X of the liquid leakage detection sensor 1. On the other hand, the outer peripheral diameter of the cable lead-out portion 23 is constant from the base end portion 23b to the intermediate portion in the axial direction of the cable lead-out portion 23, and the tip end portion 23a of the cable lead-out portion 23 gradually increases toward the tip. The diameter is small. In other words, the outer peripheral surface of the cable lead-out portion 23 extends along the axial direction of the cable lead-out portion 23 from the base end portion 23b to the intermediate portion in the axial direction of the cable lead-out portion 23, and is tapered at the tip end portion 23a. And has an inclined surface. That is, the cable lead-out portion 23 has a base end portion 23b that is thicker than the tip end portion 23a, whereby the rigidity of the cable lead-out portion 23 can be ensured.

  Note that fitting grooves 26 extending linearly along the height direction Z are formed on both sides of the cable lead-out portion 23 in the left-right direction Y on the end surface 24a of the base portion 24, respectively. Further, on both side surfaces of the base portion 24 in the left-right direction Y, engagement convex portions 27 extending linearly along the height direction Z are formed.

  Further, in the outer peripheral portion 21 of the case 14, grip portions 21 a made up of a plurality of projection groups are formed on both side portions in the left-right direction Y (see FIG. 4). The gripping part 21a serves as a mark and a slipper when the liquid leakage detection sensor 1 or the sensor main body part 11 is provided alone. In addition, a pair of protrusions 21b are formed on the outer peripheral portion 21 of the case 14 at a position closer to the front end side (opposite base side) than the gripping portion 21a, and the protrusions 21b are moved downward by a fixing jig (not shown). By pressing, vibration of the front end portion of the case 14 is prevented. Further, since the protruding portion 21b is formed at the intermediate portion in the height direction Z, when the protruding portion 21b is pressed downward by the fixing jig, the fixing jig does not protrude above the case 14. It can be configured as follows.

  The holding member 13 is formed with a fixing portion 31 having a bolt insertion hole 31a through which the fixing bolt is inserted. In addition, the holding member 13 extends in the height direction Z from the fixing portion 31 and surrounds the periphery of the cable lead-out portion 23 of the case 14, and holds the base 24 of the case 14 extending from the surrounding portion 32. A piece 33 is formed. The cable 16 led out from the cable lead-out portion 23 of the case 14 is inserted into a notch 32 a formed in the surrounding portion 32.

  As shown in FIG. 3, the holding piece 33 is formed with a pair of fitting protrusions 34 extending in the height direction Z and protruding forward, and the fitting protrusions 34 are fitted to the fittings of the base 24 of the case 14. The mating groove 26 is fitted. The fitting convex portion 34 has a shape that becomes wider toward the tip, and the fitting groove 26 of the fitting case 14 also has a shape corresponding to the fitting convex portion 34, whereby the case 14 is separated from the holding member 13. It is prevented from coming off forward.

  Further, the holding piece 33 is formed with a pair of engaging grooves 35 facing in the left-right direction Y, and the engaging grooves 35 are engaged with the engaging convex portions 27 of the base 24 of the case 14. A projection 27a projecting in the left-right direction Y is formed at the center in the height direction Z of each engagement projection 27, and this projection 27a is locked in a locking hole 35a formed in the engagement groove 35. The This prevents the sensor body 11 from being detached from the holding member 13 in the height direction Z.

  The base portion 12 interposed between the bottom portion 22 of the case 14 and the installation surface P has a substantially disk shape, and has substantially the same shape as the case 14 of the sensor main body portion 11 when viewed from the height direction Z. Further, the base portion 12 is made of a fluororesin such as PFA having heat resistance and chemical resistance in the same manner as the case 14. A pair of convex portions 12 a projecting on both sides in the left-right direction Y are formed at the rear portion (end portion in the front-rear direction X) of the base portion 12. On the other hand, a pair of locking portions 31b extending forward from the fixed portion 31 are formed at positions corresponding to the protruding portions 12a in the holding member 13, and the locking portions 31b are locked to the protruding portions 12a of the base portion 12, respectively. Has been. Thereby, it is prevented that the base part 12 remove | deviates from the holding member 13 ahead.

  Further, the base portion 12 is formed with a locking projection 12b that protrudes upward from the outer edge thereof, and this locking projection 12b is circumferentially connected to a locking recess 21c formed at the lower end of the outer peripheral portion 21 of the case 14. As a result, the base portion 12 is prevented from rotating in the circumferential direction with respect to the case 14.

  A curved convex surface 41 (inclined surface) is formed on the surface (upper surface) of the cover 15 so as to descend toward the outer edge, and the curved convex surface 41 has a cross groove along the front-rear direction X and the left-right direction Y. 42 (groove part) is formed. The curved convex surface 41 and the cross groove 42 guide the adhered liquid to the outer edge of the cover 15. Further, on the curved convex surface 41, three display portions 43 arranged in the left-right direction Y are formed so as to overlap the cross groove 42. Note that the center of the cross groove 42 coincides with the center of the cover 15, and the middle display portion 43 overlaps the center of the cross groove 42.

  The curved convex surface 41 has a curved shape (dome shape) that is convex upward. Further, as shown in FIG. 4, the curved convex surface 41 has a circular shape in plan view, and the edge 41 a is set slightly inside the outer peripheral surface 14 b of the case 14. Further, the outer portion (edge) of the upper surface Ha of the housing H with respect to the curved convex surface 41 is formed to be horizontal when the leakage detection sensor 1 is installed on the installation surface P (see FIG. 7). A boundary portion K between the opening 14 a of the case 14 and the cover 15 is positioned in a horizontal portion on the upper surface Ha of the housing H. The opening 14a of the case 14 and the cover 15 are laser welded by irradiating the boundary portion K with laser light.

  Under each display portion 43, as shown in FIGS. 7 and 8, a light guide portion 44 extending from the back surface side along the height direction Z toward the inside of the case of the cover 15 is formed. The lower end of each light guide 44 is close to the upper side of the LED 20 on the substrate 17, and light from each LED 20 mainly passes through the corresponding light guide 44 and is emitted from each display 43. ing. It should be noted that the liquid leakage detection state of the liquid leakage detection sensor 1 is indicated by the lighting state of the display unit 43.

  Note that a positioning projection 45 (see FIGS. 4 and 8) that engages with a recess (not shown) formed in the case 14 is formed on the back surface of the rear end portion of the cover 15. The cover 15 is positioned with respect to. Further, reinforcing ribs 46 are formed on the back surface of the cover 15 so that the rigidity of the cover 15 is improved (see FIG. 8).

  Such a leak detection sensor 1 has two detection parts 51 for detecting the liquid between the installation surface P and the base part 12 (see FIGS. 5 and 7). The two detection units 51 are arranged in parallel in the front-rear direction X, one is formed at a position near the front edge of the liquid leakage detection sensor 1, and the other is formed at a position near the center of the liquid leakage detection sensor 1. ing.

  Each detector 51 includes a pair of case-side raised portions 52, a pair of base-side raised portions 53, a light projecting element 18, and a light receiving element 19. The pair of case-side raised portions 52 are juxtaposed in the left-right direction Y on the bottom portion 22 of the case 14 and are formed so as to protrude downward (see FIG. 7). Similarly, the pair of base-side raised portions 53 are arranged in parallel with the base portion 12 in the left-right direction Y, and are formed so as to protrude downward. Each case-side raised portion 52 and each base-side raised portion 53 are configured to overlap with each other in the height direction Z, and a part of each base-side raised portion 53 comes into contact with the installation surface P. ing. Further, the light projecting element 18 and the light receiving element 19 are respectively disposed above the case-side raised portions 52. In such a detection part 51, the inner surface of each base part side protruding part 53 serves as a detection surface 51a for detecting the liquid on the installation surface P.

  As shown in FIG. 9, in such a liquid leakage detection sensor 1, if the liquid is not in contact with the detection surface 51 a of the detection unit 51, the light emitted from the light projecting element 18 is one (the left side in FIG. 9). ) Through the case-side raised portion 52 and the base-side raised portion 53. At this time, the passed light is refracted by the detection surface 51 a, passes through the other case-side raised portion 52 and the base-side raised portion 53, and is received by the light receiving element 19. On the other hand, in the state where the liquid is in contact with the detection surface 51a, the refractive index on the detection surface 51a changes, so the amount of light received by the light receiving element 19 changes from the state where the liquid is not in contact with the detection surface 51a. That is, the amount of light received by the light receiving element 19 changes according to the presence or absence of liquid between the base-side raised portions 53, and the light receiving element 19 outputs a light reception signal corresponding to the amount of received light to a control unit (not shown). Then, the control unit detects the presence or absence of liquid (leakage) based on the light reception signal from the light receiving element 19, and when detecting the liquid, for example, transmits a stop signal to the manufacturing apparatus D via the cable 16. The manufacturing apparatus D is stopped.

Next, a method for manufacturing the leak detection sensor 1 will be described.
First, the sensor main part such as the board 17 is assembled into the case 14 from the opening 14 a and the cable 16 is inserted into the insertion hole 25 of the cable lead-out part 23, and then the conductor of the cable 16 is connected to the board 17. Thereafter, the cover 15 is assembled to the opening 14a of the case 14 by laser welding, and the upper opening 14a of the case 14 is closed in a watertight manner. At the time of laser welding, the boundary between the outer edge of the cover 15 and the case 14 is irradiated with laser light for welding. More specifically, during the laser welding, the cover 15 is pressed from the upper side to the lower side (case 14 side), whereby the cover 15 is moved in the height direction Z and the height direction Z with respect to the case 14. Are in close contact with each other in the direction (radial direction) orthogonal to the laser beam, and laser welding is performed in this close contact state. Thereby, the sealing performance between the opening 14a of the case 14 and the cover 15 is improved. The case 14 and the cover 15 are made of the same color and the same material (fluororesin), but the laser welding of the case 14 and the cover 15 is performed by irradiating the two overlapped members with laser light from the stacking direction. This method is not a method of irradiating, but a method of irradiating laser light directly to the boundary portion. Therefore, it is possible to achieve good welding even when laser welding of fluororesins is performed.

  Next, the cable lead-out portion 23 of the case 14 and the cable 16 are laser-welded. At this time, as shown in FIGS. 10 and 11A, the sensor main body 11 is placed on a jig (not shown) so that the tip 23a of the cable lead-out portion 23 faces upward in the vertical direction. Thereby, the lead-out direction of the cable 16 faces the upper side in the vertical direction. Thereafter, while rotating the sensor main body 11 and the cable 16 around the axis C of the cable lead-out portion 23, the laser light L is emitted from the direction orthogonal to the axis C to the distal end portion 23a of the cable lead-out portion 23 by a laser device (not shown). Irradiate. In FIG. 11, the gap between the inner periphery (insertion hole 25) of the cable lead-out portion 23 and the cable 16 is exaggerated.

  In addition, it is desirable to use a laser device that emits laser light L having a wavelength suitable for the material of the object to be welded (wavelength at which energy is easily absorbed), such as PFA of this embodiment. For the resin, a laser device that emits far-infrared laser light (a wavelength is approximately 10.64 μm) such as a carbon dioxide laser is used. In other words, a carbon dioxide laser may be used as it is for the laser device, or a laser device that amplifies the wavelength (1.064 μm) by 10 times using a YAG laser and emits it. Further, the wavelength of the YAG laser is not suitable for welding of fluororesin, but the outer member 16a of the cable 16 and the cable lead-out portion 23 (more specifically, the inner peripheral side of the cable lead-out portion 23 (the insertion hole 25 side) )) And a material that can absorb the wavelength of the YAG laser are added slightly to make the output energy extremely high, so that welding can be performed even with laser light in the wavelength band of the YAG laser. However, if the cable lead-out portion 23 and the cable 16 are welded using such a high-power laser beam, the conductor in the cable 16 may be affected and the conductor may be damaged. In this embodiment, it is desirable to use laser light L (carbon dioxide gas laser) having a wavelength of 10.64 μm for laser welding.

  In the laser welding of the cable lead-out part 23, the position where the laser light L is irradiated (the position in the vertical direction) is thick in order to easily apply the energy of the laser light L to the boundary part between the cable lead-out part 23 and the cable 16. Is set at a position very close to the tip of the cable lead-out portion 23. And the sensor main-body part 11 and the cable 16 are rotated dozens of times in the state irradiated with the position of the perpendicular direction of the laser beam L being constant. Thereafter, the emission position of the laser beam L is slightly shifted downward in the vertical direction (base end side of the cable lead-out portion 23), and the sensor body 11 and the cable 16 are again tens of times while irradiating the laser beam L at that position. Rotate. The process of irradiating the laser beam L with its emission position slightly shifted downward in the vertical direction is performed several times. Then, in the distal end portion 23 a of the cable lead-out portion 23, a portion that has absorbed energy and generated heat is melted, and the melted resin flows downward in the vertical direction due to gravity, and between the insertion hole 25 and the outer skin member 16 a of the cable 16. (See FIG. 11B). Thereby, while the inner peripheral surface of the cable derivation | leading-out part 23 and the outer skin member 16a of the cable 16 are welded, the space | interval is reliably sealed. In addition, since the opening part formed in case 14 has only two places, the opening 14a for assembling an internal component, and the cable derivation | leading-out part 23, these two places are sealed by laser welding as mentioned above. Thus, the water tightness inside the case 14 is ensured.

  In this way, by irradiating the laser beam L (carbon dioxide laser) from the outer peripheral side of the cable lead-out portion 23 through which the cable 16 is inserted, the cable 16 and the cable lead-out portion 23 including the lead wires inside the outer skin member 16a. It is supposed to be welded. As a result, after the cable lead-out portion 23 and the outer skin member 16a are welded by heat welding other than laser welding, the manufacturing method can be simplified as compared with the case where the conductor is inserted into the outer skin member 16a. ing. Moreover, in this embodiment, since the front-end | tip part 23a of the cable derivation | leading-out part 23 has a tapering shape and the laser beam L is irradiated and laser-welded to the front-end | tip part 23a, the laser beam L of the cable 16 is bordered Energy can be applied satisfactorily, and the cable lead-out portion 23 and the cable 16 are reliably laser-welded.

Next, characteristic effects of the present embodiment will be described.
(1) A detection unit 51 for detecting liquid that has entered between the lower surface of the housing H placed on the installation surface P and the installation surface P is provided. A curved convex surface 41 is provided as an inclined surface that is inclined downward toward the periphery of the upper surface. For this reason, the liquid adhering to the curved convex surface 41 flows to the edge of the upper surface Ha of the housing H and adheres to the installation surface P along the side surface (outer peripheral surface 14b) of the housing H. As a result, the liquid adhering to the upper surface Ha of the housing H can easily enter the space between the installation surface P and the housing H (specifically, between the installation surface P and the base portion 12). Stable liquid detection at the unit 51 becomes possible.

  (2) Since the curved convex surface 41 provided on the upper surface Ha of the cylindrical housing H forms a dome shape, the liquid adhering to the curved convex surface 41 can be suitably flowed to the installation surface P. As a result, the detection unit More stable liquid detection at 51 is possible.

  (3) The curved convex surface 41 is provided with a cross groove 42 as a groove extending toward the periphery of the upper surface Ha of the housing H. For this reason, the liquid adhering to the curved convex surface 41 by the cross groove 42 can be made to easily flow on the installation surface P.

  (4) On the side surface (outer peripheral surface 14 b) of the housing H, a cable lead-out portion 23 for leading the cable 16 to the outside of the housing H is formed so as to protrude. For this reason, compared with the structure which forms the cable derivation | leading-out part 23 in the upper surface Ha of the housing H, the liquid adhering to the curved convex surface 41 can be made to flow easily by the installation surface P. FIG.

(5) Since the display part 43 is provided on the curved convex surface 41 that is easy to flow down even if liquid leakage adheres, it is possible to suppress a reduction in the visibility of the display part due to liquid leakage.
(6) In the liquid leakage detection sensor 1 of the present embodiment, the cable lead-out portion 23 made of a fluororesin and the outer skin member 16a of the cable 16 are laser-welded and sealed between them, and the distal end portion of the cable lead-out portion 23 23a has a tapered shape. Therefore, even if the thickness of the base end portion 23b of the cable lead-out portion 23 is configured to be thick, the tip portion 23a of the cable lead-out portion 23 that is tapered can be configured to be thin. The energy of the laser beam L can be favorably applied to the boundary portion with the cable 16, and the cable lead-out portion 23 and the cable 16 can be surely laser-welded. As a result, while the thickness of the base end portion 23b of the cable lead-out portion 23 is increased to make the cable 16 sufficiently rigid for holding the cable 16, the cable lead-out portion 23 and the cable 16 are favorably laser welded at the distal end portion 23a. It becomes possible to do. Moreover, since it becomes possible to weld the inner peripheral surface of the cable lead-out portion 23 and the outer skin member 16a of the cable 16 in a state where a conducting wire or the like is inserted into the outer skin member 16a of the cable 16, a leak detection sensor 1 can be simplified.

(7) Since the tip portion 23a of the cable lead-out portion 23 has a tapered shape, the tip portion 23a of the cable lead-out portion 23 that is tapered can be easily formed.
(8) With the case 14 disposed so that the distal end portion 23a of the cable outlet portion 23 faces upward in the vertical direction, the distal end portion 23a of the cable outlet portion 23 and the cable 16 are laser welded. For this reason, the tip portion of the cable lead-out portion 23 melted by the energy of the laser light L flows in the direction of gravity and easily enters the gap between the inner peripheral surface of the cable lead-out portion 23 and the cable 16. And between the cable derivation | leading-out part 23 and the cable 16 can be more reliably sealed with resin which entered the clearance gap.

  (9) While the case 14 and the cable 16 are rotated about the axial center of the cable lead-out portion 23, laser welding of the tip portion 23a of the cable lead-out portion 23 and the cable 16 is performed. For this reason, it becomes possible to laser-weld easily the front-end | tip part 23a and the cable 16 of the cable derivation | leading-out part 23 which faced the perpendicular direction upper side.

(10) Since the distal end portion 23a of the cable lead-out portion 23 and the cable 16 are laser-welded by the far-infrared laser light L, laser welding can be performed more reliably.
(11) In order to perform laser welding of the tip portion 23a of the cable lead-out portion 23 and the cable 16 by irradiating the tip portion 23a of the cable lead-out portion 23 with the laser light L from the direction orthogonal to the axis of the cable lead-out portion 23, Laser welding can be suitably performed between the distal end portion 23 a of the cable lead-out portion 23 and the cable 16.

  (12) After laser welding the opening 14a for assembling the internal parts in the case 14 and the cover 15 that closes the opening 14a, the tip portion 23a of the cable lead-out portion 23 and the cable 16 are laser-welded. Since the opening area of the opening 14a is generally larger than the opening area of the cable lead-out portion 23, the welding area between the opening 14a of the case 14 and the cover 15 is also larger than the welding area between the cable lead-out portion 23 and the cable 16. Therefore, the amount of heat generated by laser welding between the opening 14 a of the case 14 and the cover 15 is larger than the amount of heat generated by welding the cable lead-out portion 23 and the cable 16. For this reason, if the front end portion 23a of the cable lead-out portion 23 and the cable 16 are laser-welded before the laser welding between the opening 14a of the case 14 and the cover 15, the cable lead-out portion 23 is sealed by laser welding. As a result, the heat dissipation path for releasing the heat inside the case 14 is cut off, so that the internal temperature rises due to the heat generated by laser welding between the opening 14a of the case 14 and the cover 15, and as a result, the case 14 expands too much. There is a possibility that the opening 14a and the cover 15 are not well welded. In that respect, in this embodiment, the internal heat of the case generated by laser welding of the opening 14a of the case 14 and the cover 15 is released to the outside from the cable lead-out portion 23 before the cable 16 is welded. As a result, the opening 14a of the case 14 and the cover 15 can be reliably sealed by laser welding.

In addition, you may change embodiment of this invention as follows.
In the above embodiment, the edge 41a of the curved convex surface 41 is set slightly inside the outer peripheral surface 14b of the case 14 in plan view, but the edge 41a of the curved convex surface 41 coincides with the outer peripheral surface 14b of the case 14. The configuration, that is, the curved convex surface 41 may be configured to continuously incline from the center of the upper surface of the housing to the peripheral edge (see FIG. 12). According to this structure, since the whole from the center part of the upper surface Ha of the housing H to a periphery becomes the curved convex surface 41, the liquid adhering to the curved convex surface 41 can be made to flow easily by the installation surface P, and the more stable liquid Detection is possible.

  Further, in a configuration in which such a configuration is simply applied to the above-described embodiment, the curved convex surface 41 is configured by the upper surface of the case 14 (outer peripheral portion 21) and the upper surface of the cover 15, as shown in FIG. The boundary portion K between the opening 14 a and the cover 15 is located on the curved convex surface 41. For this reason, for example, it is difficult to perform heat welding by uniformly pressing the upper surface Ha of the housing H with a heating plate, but the cover 15 can be easily welded to the opening 14a of the case 14 by using laser welding as in the above embodiment. Is possible.

  In the above embodiment, the housing H has a cylindrical shape, and the inclined surface (curved convex surface 41) of the upper surface Ha has a dome shape. However, the present invention is not particularly limited to this, and for example, the housing H has a quadrangular prism shape and is inclined. The surface may be pyramidal.

  In the above embodiment, the base portion 12 is interposed between the case 14 and the installation surface P. However, the present invention is not particularly limited thereto, and the case 14 is directly placed on the installation surface P. It is good also as a structure.

  -In above-mentioned embodiment, although the front-end | tip part 23a of the cable derivation | leading-out part 23 made the taper shape, it is not specifically limited to this, For example, it is good also as a shape which forms a level | step difference in steps and tapers gradually. . Moreover, although the front-end | tip part 23a of the cable derivation | leading-out part 23 of the said embodiment was made into the taper shape which has a linear inclination by the side view, it can also be set as the taper shape which has the inclination curved inside or outside in addition to this, for example. Good.

  In the above embodiment, the front end portion 23a of the cable lead-out portion 23 is directed upward in the vertical direction, and in this state, the front end portion 23a of the cable lead-out portion 23 is irradiated with the laser beam L from the direction orthogonal to the axis C and laser-welded. However, the present invention is not limited to this.

  In the above embodiment, laser welding is performed between the tip end portion 23a of the cable lead-out portion 23 and the cable 16 while rotating the case 14 and the cable 16 around the axis C of the cable lead-out portion 23. However, the present invention is particularly limited to this. Instead, the case 14 and the cable 16 may be fixed, and the laser light L may be rotated around the axis C of the cable lead-out portion 23.

  In the above embodiment, after laser welding the opening 14 a of the case 14 and the cover 15, the tip end portion 23 a of the cable lead-out portion 23 is laser-welded. Before the opening 14 a and the cover 15 are laser welded, the tip end portion 23 a of the cable lead-out portion 23 may be laser welded.

  In the above embodiment, the cable 16 is for electrical connection between the sensor main part and the outside, but is not particularly limited to this, and may be a cable for optical fiber.

  -In above-mentioned embodiment, although this invention was applied to the leak detection sensor 1, it is not specifically limited to this, You may apply to another detection sensor.

  DESCRIPTION OF SYMBOLS 1 ... Liquid leak detection sensor, 12 ... Base part which comprises a housing, 14 ... Case (housing main body) which comprises a housing, 15 ... Cover which comprises a housing, 14a ... Opening, 16 ... Cable, 16a ... Skin member, 23 DESCRIPTION OF SYMBOLS ... Cable lead-out part, 23a ... Tip part of cable lead-out part, 41 ... Curve convex surface (inclined surface), 42 ... Cross groove (groove part), 43 ... Display part, 51 ... Detection part, H ... Housing, Ha ... Upper surface of housing , L: Laser light.

Claims (6)

A detection sensor comprising a detection unit for detecting liquid that has entered between the lower surface of the housing placed on the installation surface and the installation surface,
The upper surface of the housing is provided with an inclined surface that is inclined downward from the center thereof toward the periphery of the upper surface ,
The detection sensor , wherein the inclined surface is provided with a groove extending toward the periphery of the upper surface of the housing . The detection sensor according to claim 1,
The detection sensor according to claim 1, wherein the housing has a cylindrical shape, and the inclined surface on the upper surface has a dome shape. The detection sensor according to claim 1 or 2,
The detection sensor according to claim 1, wherein the inclined surface is continuously inclined from a center portion to a peripheral edge of the upper surface of the housing. The detection sensor according to any one of claims 1 to 3 ,
A detection sensor, wherein a cable lead-out portion for leading a cable out of the housing is formed on a side surface of the housing. In the detection sensor according to any one of claims 1 to 4 ,
A detection sensor, wherein a display portion is provided on the inclined surface. The detection sensor according to any one of claims 1 to 5 ,
The housing comprises a housing body having an opening for assembling internal components on the upper surface side, and a cover for watertightly closing the opening of the housing body,
The inclined surface is composed of the housing body and the upper surface of the cover,
The detection sensor, wherein the cover is fixed to the opening of the housing body by laser welding.

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