JP2009117217A - Diaphragm for pressure switch and pressure switch provided with the same - Google Patents

Abstract

To provide a diaphragm for a pressure switch in which an inner peripheral edge portion of a seal diaphragm is hermetically bonded and fixed to an outer peripheral edge portion of a center plate, and a sealing force of the diaphragm for hermetically fixing the outer peripheral edge portion to a peripheral edge portion of a housing is improved. To do.
In a pressure switch diaphragm which defines a housing in two chambers and operates by a pressure difference between the two chambers to drive a switch accommodated in any one of the chambers, the diaphragm is formed in a disc shape. A center plate 22 having a fitting groove 22e formed in the peripheral edge, and a fitting convex portion 23d that is annularly formed and is hermetically fitted and fixed in the fitting groove on the inner peripheral edge, and is provided on the outer peripheral edge of the housing. It consists of a seal diaphragm 23 having a fitting convex part 23e fitted in a fitting groove formed in the peripheral part and supported in an airtight manner, and the tip of at least one fitting convex part of the inner peripheral part or the outer peripheral part Is a shape having a curved surface with a convex cross section.
[Selection] Figure 3

Description

  The present invention relates to a pressure switch diaphragm that defines a housing in two chambers and operates by a pressure difference between the two chambers to drive a switch accommodated in one of the chambers, and a pressure switch including the diaphragm.

  When the gas from a water heater or boiler burns, the air fan rotates and exhausts the exhaust gas. However, if the gas burns while the air fan is not rotating due to a failure, etc., the optimal combustion control can be performed. There is a risk of disappearing. For this reason, a pressure switch that transmits the wind pressure as an external force and detects the contact of the contacts is used to detect the air blown from the air fan.

  FIG. 9 is a cross-sectional view showing an example of the pressure switch. The pressure switch is mounted on and fixed to the bottomed cylindrical housing 2 forming the lower part of the hollow housing 1 as a container, and the housing 2 is a hollow casing. A bottom-covered cylindrical cover 3 that forms the upper part of the switch, a switch 4 comprising a snap action mechanism accommodated in the housing 2, and a housing 2 that is interposed between the housing 2 and the cover 3 and accommodates the switch 4 The low-pressure chamber 5 is hermetically defined, the high-pressure chamber 6 is hermetically defined on the cover 3 side, and a diaphragm 7 as an external force transmission mechanism for operating the switch 4 is configured.

  The diaphragm 7 is formed such that the inner peripheral edge of the seal diaphragm 9 is fixed to the outer peripheral edge of the center plate 8, and the plunger 8 a protrudes into the pressure chamber 5 at the center of the lower surface of the center plate 8. The outer peripheral edge portion of the seal diaphragm 9 is sandwiched between the outer peripheral edge portion 2b of the housing 2 and the outer peripheral edge portion 3b of the cover 3 and is airtightly fixed.

  The pressure switch 4 is mounted on a base disposed in the low-pressure chamber 5 and is an operating point where the tip of the plunger 8a comes into contact with a movable piece integrally formed at the center position of the leaf spring 4a constituting the snap action mechanism. 4b is provided. The low pressure chamber 5 is opened to the atmosphere through a port 2 a as a gas introduction hole formed in the housing 2, and the high pressure chamber 6 is connected to the water heater through a port 3 a as a gas introduction hole formed in the cover 3. Is connected to the exhaust pipe (smoke).

  When a pressure difference (differential pressure) occurs between the low pressure chamber 5 and the high pressure chamber 6, an external force is applied to the upper surface of the center plate 8 by the diaphragm 7 receiving the differential pressure. This external force displaces the membrane 9a of the seal diaphragm 9 to push down the center plate 8, and acts as a driving force on the operating point 4b with which the plunger 8a abuts. The leaf spring 4a to which the driving force is transmitted from the diaphragm 7 performs the switching operation of the contact 4c. Thus, the switch 4 is turned on / off to detect the rotation / stoppage of the air fan.

  As shown in FIGS. 9 and 10, the diaphragm 7 has an inner peripheral edge of a silicon rubber seal diaphragm 9 that is annularly connected to an outer peripheral edge of a disc-shaped center plate 8 made of a resin member. A plunger 8a for operating the switch 4 is formed at the center of the lower surface, and a fitting groove 8b having a rectangular cross section is formed on the entire upper surface of the outer peripheral edge.

  The seal diaphragm 9 is formed with a fitting convex part 9b and a fitting convex part 9c having a square cross section over the entire circumference on the lower surfaces of the inner peripheral edge part and the outer peripheral edge part of the annular film 9a. Then, the fitting convex portion 9b of the seal diaphragm 9 is fitted into the fitting groove 8b of the center plate 8, and the rib 8c that is erected over the entire circumference inside the fitting groove 8b is caulked with heat to the fitting convex portion. The lower surface 9b 'of 9b is brought into intimate contact with the bottom surface 8b' of the fitting groove 8b and is airtightly fixed and integrated.

  The fitting protrusion 9c at the outer peripheral edge of the seal diaphragm 9 is fitted into a fitting groove 2c having a square cross section formed over the entire circumference on the upper surface of the outer peripheral edge 2b of the housing 2, as shown by a two-dot chain line. The lower surface 3b ′ of the outer peripheral edge portion 3b of the cover 3 is pressed to bring the lower surface 9c ′ of the fitting convex portion 9c into close contact with the bottom surface 2c ′ of the annular groove 2c, and at a predetermined interval in the circumferential direction on the outer peripheral edge portion 3b of the cover 3 A plurality of pin-shaped protrusions 2d formed corresponding to the respective holes 3d along the circumferential direction on the upper surface of the outer peripheral edge 2b of the housing 2 are passed through the plurality of holes 3d that are erected. The tip is caulked with heat and fixed in an airtight manner (see, for example, Patent Document 1).

  The seal diaphragm 9 is formed by injection molding of silicon rubber, and FIG. 11 shows an example of a mold for molding the seal diaphragm 9. The mold 10 includes an upper mold 11 and a lower mold 12, and an injection port 11 a of molten silicon rubber is formed at the center of the upper mold 11. A film of the seal diaphragm 9 is formed on the upper surface of the lower mold 12. An annular recess (cavity) 12a having a shallow depth for forming 9a, and a quadrangular cross section for forming fitting protrusions 9b and 9c on the inner and outer peripheral edges of the annular recess 12a. Annular recesses (cavities) 12b and 12c are formed.

The silicon rubber injected (filled) from the injection device (not shown) into the injection port 11a of the upper mold 11 in a molten state as indicated by an arrow spreads in a disk shape and has an annular recess 12b, an annular recess 12a, The disc-shaped seal diaphragm is formed by sequentially flowing into the annular concave portion 12c to form a disc-shaped seal diaphragm. After being cooled, the disc is removed from the mold 10 and the disc portion inside the fitting convex portion 9b on the inner peripheral edge is removed. Thus, an annular seal diaphragm 9 is formed.
USP 5,421,242 (column 3, lines 33-47, FIG. 5)

  However, the diaphragm 7 having the above-described structure is fitted into the fitting groove 8b of the center plate 8 because the fitting convex part 9b on the inner peripheral edge of the seal diaphragm 9 has a quadrangular cross section as shown in FIG. When the rib 8c is integrated by caulking with heat, the fitting protrusion 9b has no escape space for deformation in the direction indicated by the arrow in FIG. Since the joint protrusion 9b is not easily crushed and hardly deforms, the sealing force between the lower surface 9b ′ and the bottom surface 8b ′ of the fitting groove 8b is reduced, and the sealing performance (adhesion) is low. Further, in order to crush the entire lower surface 9b ', it is necessary to increase the caulking force (pressing force), which makes it difficult to fix by heat caulking. The same applies to the fitting convex portion 9c having a quadrangular cross section at the outer peripheral edge portion of the seal diaphragm 9.

  Moreover, since the fitting convex part 9b of the inner peripheral part of the seal diaphragm 9 and the fitting convex part 9c of the outer peripheral part have a quadrangular cross section, the moldability is improved when molding by injection molding as shown in FIG. There is a problem that there are many molding defects.

  That is, the molten silicon rubber injected from the injection port 11a of the upper mold 11 spreads concentrically in a disc shape and enters an annular recess (cavity) 12b having a rectangular cross section of the lower mold 12. 12A sequentially flows as indicated by lines A, B, C, and D, and further passes through an annular recess 12a as indicated by lines E and F, as shown in FIG. 12B. As indicated by lines G, H, and I, the annular recess (cavity) 12c having a quadrangular shape sequentially flows and fills.

  However, when the silicon rubber melted due to the structure of the mold flows into the concave portion (cavity) 12b having a quadrangular cross section inside the lower die 12, air is supplied to both corners 12b ′ and 12b ′ at the lower end of the concave portion 12b. Traps (portions where air is pushed in) 12e and 12f are generated. In the outer annular recess (cavity) 12c, air traps 12g and 12h are similarly generated at both corners 12c 'and 12c' at the lower end. In addition, a plurality of air venting gaps (small holes) (not shown) are formed between the upper mold 11 and the outer corner of the upper end of the outer annular recess (cavity) 12c, and an air trap is generated. do not do.

  When an air trap occurs when molding the seal diaphragm 9 in this way, the surface of the corners on both ends of the fitting projections 9b, 9c of the formed seal diaphragm 9 becomes rough, the corners are chipped, Or it becomes easy to produce a bubble in a corner. For this reason, the molding defect of a seal diaphragm increases and a yield worsens.

  An object of the present invention is to improve the sealing force of a diaphragm in which the inner peripheral edge of the seal diaphragm is airtightly bonded and fixed to the outer peripheral edge of the center plate, and the outer peripheral edge is sandwiched between the peripheral edges of the housing and fixed in an airtight manner. Another object is to provide a pressure switch diaphragm and a pressure switch including the same.

In order to solve the above-described problem, a diaphragm for a pressure switch according to the present invention includes:
In the pressure switch diaphragm which defines the inside of the housing in two chambers and operates by the pressure difference between the two chambers to drive the switch accommodated in one of the chambers,
The diaphragm has a disc shape and has a center plate in which a fitting groove is formed on the entire outer periphery of the outer periphery, and an annular shape and is fitted and fixed in the fitting groove on the inner periphery on the entire periphery. And is fitted over the entire circumference in a fitting groove formed on the outer peripheral edge of the housing and formed on the outer peripheral edge of the housing. It consists of a seal diaphragm with a fitting convex part,
The tip of the fitting convex portion of at least one of the inner peripheral edge portion or the outer peripheral edge portion of the seal diaphragm facing the bottom surface of the center plate or the fitting groove of the housing has a curved surface with a convex cross section. .

  The fitting protrusion formed on the inner peripheral edge of the seal diaphragm is fitted into the fitting groove formed on the outer peripheral edge of the center plate and joined, and the joint is caulked with heat to fix the tip of the fitting convex. Integrate by closely contacting the bottom surface of the fitting groove. The fitting convex part has a convex curved surface, which makes it easier to deform and crush compared to the shape before deformation, and it is good because the escape space is secured in the fitting groove when deforming And is in close contact with the bottom surface of the fitting groove. Further, the fitting convex portion formed on the outer peripheral edge portion of the seal diaphragm is fitted into the fitting groove formed on the outer peripheral edge portion of the housing, and the lower surface of the outer peripheral edge portion of the cover is pressed and fixed. The fitting convex part has a convex curved surface, which makes it easier to deform and crush compared to the shape before deformation, and it is good because the escape space is secured in the fitting groove when deforming And is in close contact with the bottom surface of the fitting groove. Thereby, it is possible to form a diaphragm having a large sealing force.

  Moreover, since the fitting convex part has a substantially U-shaped cross section, the surface area is small as compared with the case where the conventional cross section is a square shape, so that the releasability is good. Further, since the fitting convex portion has a substantially U-shaped cross section, the resin can be filled at a lower pressure than the quadrangular cross section. Furthermore, since the surface area of the mold is smaller than that of the quadrangular cross section, there is an advantage that pinholes due to adhesion of minute flashes to the mold are less likely to occur.

  Preferably, the seal diaphragm has a curved surface with a convex section at the tip of the fitting convex portion at the inner edge.

  A fitting convex portion formed on an inner peripheral edge portion joined to an outer peripheral edge portion of the center plate of the seal diaphragm has a convex curved surface at a tip facing the bottom surface of the fitting groove of the center plate. The sealing force between the portion and the bottom surface of the fitting groove is increased, and the joint portion with the center plate can be reliably sealed.

Moreover, the diaphragm for pressure switches which concerns on Claim 2 of this invention is a diaphragm for pressure switches of Claim 1,
The seal diaphragm is formed of silicon rubber.

  Silicon rubber is excellent in durability, corrosion resistance, and chemical properties, and a diaphragm formed of the silicon rubber can be applied to a pressure switch used in various environments.

Moreover, the diaphragm for pressure switches which concerns on Claim 3 of this invention is a diaphragm for pressure switches of Claim 1 or Claim 2,
The seal diaphragm is formed by injection molding.

  By forming the seal diaphragm by injection molding, it is possible to form a large number of seal diaphragms having isotropic properties and excellent durability. Further, the cost can be reduced.

A pressure switch according to claim 4 of the present invention is
In the pressure switch that drives the switch housed in one of the chambers with a diaphragm that is defined by the pressure difference between the two chambers in the housing.
The pressure switch diaphragm according to any one of claims 1 to 3 is provided.

  Silicon rubber is excellent in durability, corrosion resistance, and chemical resistance, and by using a diaphragm made of silicon rubber for the pressure switch, it has a corrosive gas pressure switch especially used in semiconductor manufacturing equipment etc. It is possible to apply this diaphragm.

  According to the present invention, in the diaphragm for a pressure switch that defines the inside of the housing in two chambers and operates by the pressure difference between the two chambers to drive the switch accommodated in one of the chambers, the outer peripheral edge of the center plate is fitted. By facilitating deformation of at least one fitting convex portion of the inner peripheral edge portion of the seal diaphragm fitted into the groove or the outer peripheral edge portion of the seal diaphragm fitted into the fitting groove at the peripheral edge portion of the housing. And the sealing force between the front-end | tip of a fitting convex part and the bottom face of a fitting groove can be enlarged. As a result, a pressure switch with excellent airtightness can be configured.

  Hereinafter, a diaphragm for a pressure switch according to an embodiment of the present invention will be described with reference to the drawings. 1 is a top view of a pressure switch diaphragm (hereinafter simply referred to as “diaphragm”) 21 according to the present invention, FIG. 2 is a bottom view of the diaphragm 21 shown in FIG. 1, and FIG. 3 is a part of the diaphragm shown in FIG. It is sectional drawing.

  The diaphragm 21 includes a disc-shaped center plate 22 and an annular seal diaphragm 23, and the inner peripheral edge 23 b of the film 23 a of the seal diaphragm 23 is airtightly joined to the outer peripheral edge 22 d of the upper surface 22 a of the center plate 22. It is fixed in the state. Further, a plunger 22c is formed to extend downward at the center position of the lower surface 22b of the center plate 22.

  The center plate 22 is formed with a fitting groove 22e having a square cross section as shown in FIG. 4 on the outer peripheral edge portion 22d of the upper surface 22a, as shown in FIG. 4, and ribs 22f are formed on the inner side of the fitting groove 22e. It is erected across. The inner peripheral surface of the fitting groove 22e and the outer peripheral surface of the rib 22f are flush with each other. The center plate 22 is formed of a resin member.

  The seal diaphragm 23 has a fitting convex portion 23d as shown in FIG. 3 formed on the lower surface of the inner peripheral edge portion 23b of the disc-shaped film 23a, and is formed on the lower surface of the outer peripheral edge portion 23c of the film 23a. A fitting projection 23e as shown in FIGS. 2 and 3 is formed over the entire circumference.

  As shown in FIG. 4, the fitting convex portion 23d of the inner peripheral edge portion 23b has a height slightly higher than the depth of the fitting groove 22e of the center plate 22, and a width slightly smaller than the width of the fitting groove 22e. Is formed. And the front-end | tip 23d 'facing the bottom face 22e' of the fitting groove 22e of the fitting recessed part 23d has comprised the curved surface of a cross-sectional convex shape.

  Similarly to the fitting convex portion 23d, the fitting convex portion 23e of the outer peripheral edge portion 23c is formed in a shape in which the tip 23e 'facing the bottom surface 2c' of the fitting groove 2c shown in FIG. The height of the fitting groove 2c is slightly higher than the depth of the fitting groove 2c having a square cross section formed over the entire circumference in the outer peripheral edge 2b of the housing 2 shown in FIG. It is formed slightly narrower than the width of the groove 2c.

  In this manner, the shapes of the tips 23d ′ and 23e ′ facing the bottom surfaces 22e ′ and 2c ′ of the fitting grooves 22e and 2c of the fitting convex portions 23d and 23e are curved surfaces having a convex cross section. It becomes easy to deform in the grooves 22e and 2c, and a clearance field is secured when the grooves 22e and 2c are deformed, and the sealing force between the tips 23d 'and 23e' and the bottom surfaces 22e 'and 2c' of the fitting grooves 22e and 2c is increased. Is possible. The seal diaphragm 23 is made of silicon rubber and is formed by injection molding.

  As shown in FIG. 4, the sealing diaphragm 23 is formed so that the fitting convex portion 23 d of the inner peripheral edge portion 23 c is fitted into the fitting groove 22 e of the center plate 22, and is erected over the entire circumference inside the fitting groove 22 e. As shown in FIG. 5, the ribs 22f are caulked with heat, and the tips 23d 'of the fitting projections 23d are brought into close contact with the bottom surface 22e' of the fitting groove 22e to be integrated.

  The fitting convex portion 23d is easily deformed and crushed compared to the shape before deformation indicated by a dotted line in FIG. 5 because the tip 23d ′ has a convex curved surface, and the fitting groove 22d is deformed when deformed. By ensuring the escape space inside, it is deformed well and closely contacts the bottom surface 22e 'of the fitting groove 22e. Thereby, it is possible to form a diaphragm having a large sealing force.

  The diaphragm 21 is accommodated in a housing (housing) 2 instead of the diaphragm 7 of the pressure switch 1 shown in FIG. 9, for example, and the fitting convex portion 23e of the outer peripheral edge 23c is formed on the housing 2 as shown in FIG. The upper surface of the outer peripheral edge portion 2b is fitted into a fitting groove 2c having a square cross section formed over the entire circumference, and the lower surface 3b 'of the outer peripheral edge portion 3b of the cover 3 is pressed against the tip 23e' of the fitting convex portion 23e. A plurality of holes 3d that are in close contact with the bottom surface 2c ′ of the annular groove 2c and are provided at predetermined intervals in the circumferential direction on the outer peripheral edge portion 3b of the cover 3 surround the upper surface of the outer peripheral edge portion 2b of the housing 2. A plurality of pin-shaped protrusions 2d formed corresponding to the respective holes 3d are penetrated along the direction, and the tip portion is caulked and fixed by heat.

  The fitting protrusion 23e is deformed and crushed as shown by the solid line from the state before the deformation shown by the dotted line in FIG. 6 because the tip 23e ′ has a convex curved surface, and the fitting groove 23e By ensuring a clearance in 2c, it is deformed well and closely contacts the bottom surface 2c 'of the fitting groove 2c. Thereby, a pressure switch having a large sealing force can be formed.

  5 and 6, the deformation amounts of the tips 23d 'and 23e' of the fitting protrusions 23d and 23e are exaggerated for easy understanding, and actually the bottom surface 22e 'of the fitting groove 22e. The bottom surface 2c 'of the fitting groove 2c is close to a line seal. A joint portion between the fitting groove 22e of the center plate 22 and the fitting convex portion 23d of the seal diaphragm 23, and a fixing portion of the fitting convex portion 23e of the seal diaphragm 23 and the fitting groove 2c of the housing 2 are caulking structures. And a line seal structure can be combined to provide a diaphragm having a large sealing force.

  Next, a molding die and a molding method for the seal diaphragm 23 will be briefly described with reference to FIGS. As shown in FIG. 7, the mold 30 includes an upper mold 31 and a lower mold 32. The upper mold 31 has an injection port 31a for injecting (filling) molten silicon rubber that opens upward in the center. The lower mold 32 is fitted into an annular shallow recess (cavity) 32a for forming the film 23a of the seal diaphragm 23 on the upper surface, and an inner peripheral edge and an outer peripheral edge of the annular recess 32a. Annular concave portions (cavities) 32b and 32c for forming the joint convex portions 23d and 23e are formed concentrically.

  The cross-sectional shapes of the annular recesses 32b and 32c are such that the bottom surfaces 32b 'and 32c' are concave corresponding to the convex curved surfaces of the tips 23d 'and 23e' of the fitting projections 23d and 23e of the seal diaphragm 23. It is formed in a substantially U shape that forms a curved surface. Note that a plurality of air venting gaps (small holes) (not shown) are formed between the upper mold 31 and the outer corner of the upper end of the outer annular recess (cavity) 32c.

  Then, molten silicon rubber is injected (filled) into the injection port 31a of the upper mold 31 of the mold 30 from an injection device (not shown). The melted silicon rubber spreads in a disk shape and forms lines A and B in an annular recess (cavity) 32b having a substantially U-shaped cross section inside the lower mold 32 as shown in FIG. , C, and D, smoothly flow in and fill as shown. The recess 32b has a substantially U-shaped cross section with a bottom surface 32b 'forming a concave curved surface, so that the molten silicon rubber is smoothly filled along the concave curved surface, and air traps are generated at both corners on the bottom. Is prevented.

  Further, after the melted silicon rubber is filled in the annular recess 32b, it passes through the annular recess (cavity) 32a as shown by lines E and F, and the outer cross section is substantially U-shaped as shown in FIG. As shown by lines G, H, and I, the annular recesses (cavities) 32c are sequentially filled and filled. The concave portion 32c has a substantially U-shaped cross section with a bottom surface 32c ′ having a concave curved surface, so that the molten silicon rubber flows and smoothly fills along the concave curved surface, and air traps are formed at the corners on both sides of the bottom portion. Occurrence is prevented. As described above, the outer corner of the upper end of the outer annular recess (cavity) 32c is formed with a plurality of air venting gaps (small holes) between the upper mold 31 and the upper end outside. Air trap does not occur.

  Moreover, since the fitting convex part 23d of the inner peripheral part of the seal diaphragm 23 and the fitting convex part 23e of the outer peripheral part have a substantially U-shaped cross section, the surface area is small compared to the case of a quadrangular cross section. Good releasability. Moreover, it becomes possible to fill the molten silicon rubber into the mold 30 at a lower pressure than that of the quadrangular cross section. Furthermore, since the surface areas of the annular recesses (cavities) 32b and 32c of the mold 30 are smaller than those of the quadrangular cross section, pinholes due to minute flash adhesion to the mold are less likely to occur.

  As a result, the surfaces of the tips 23d 'and 23e' of the fitting projections 23d and 23e of the formed seal diaphragm 23 are smoothed, so that no chipping or bubbles are generated, and molding defects are reduced. Thereby, the yield is improved.

  As described above, the seal diaphragm is injection-molded, cooled, and then taken out from the mold 30 to remove the disk portion inside the fitting convex portion 23d of the inner peripheral edge portion 23b, thereby removing the annular seal diaphragm 23 made of silicon rubber. Form.

  As described above, according to the present invention, in the diaphragm for a pressure switch that defines the inside of the housing in two chambers and operates by the pressure difference between the two chambers to drive the switch accommodated in one of the chambers, A center plate having a disc shape and a fitting groove formed on the outer periphery of the outer periphery, and a fitting that is annularly fitted and fixed to the fitting groove on the inner periphery of the inner periphery. A fitting projection that has a convex portion and is fitted over the entire circumference in a fitting groove formed on the outer peripheral edge of the entire circumference and formed on the outer peripheral edge of the housing. A seal diaphragm having a section, and a tip of the fitting convex portion of at least one of the inner peripheral edge portion and the outer peripheral edge portion of the seal diaphragm facing the bottom surface of the fitting groove of the center plate or the housing has a curved surface with a convex cross section. The fitting convex part End is easily deformed, and escape is in close contact with the bottom surface of the fitting groove becomes good deformable by being secured in the fitted groove at the time of deformation. Thereby, it is possible to form a diaphragm having a large sealing force.

  Also, by fitting the tip that faces the bottom of the fitting groove of the center plate of the fitting convex part formed on the inner peripheral edge part to be joined to the outer peripheral part of the center plate of the seal diaphragm, The sealing force between the convex portion and the bottom surface of the fitting groove is increased, and the joint portion with the center plate can be reliably sealed.

  Silicon rubber is excellent in durability, corrosion resistance, and chemical properties, and a diaphragm formed of the silicon rubber can be applied to pressure switches in various environments.

  In addition, by forming the seal diaphragm by injection molding, it is possible to mass-produce seal diaphragms that are isotropic and have excellent durability, and cost can be reduced.

  In addition, the pressure switch diaphragm described in the present embodiment is provided in a pressure switch that drives the switch housed in any one of the diaphragms that are defined by the pressure difference between the two chambers and that is divided into two chambers. Thus, the durability, corrosion resistance, and chemical resistance of the pressure switch are improved, and the pressure switch can be applied to a corrosive gas pressure switch used in a semiconductor manufacturing apparatus or the like.

It is a top view of the diaphragm for pressure switches concerning the present invention. It is a bottom view of the diaphragm for pressure switches shown in FIG. It is sectional drawing which follows the arrow line III-III of the diaphragm for pressure switches shown in FIG. It is explanatory drawing which shows the relationship between the fitting convex part of the inner peripheral part of the seal diaphragm shown in FIG. 3, and the fitting groove and rib formed in the outer peripheral part of a center plate. It is explanatory drawing of the state which fitted the fitting convex part of the inner peripheral part of the seal diaphragm shown in FIG. 4, and the fitting groove of the outer peripheral part of the center plate, and was airtightly fixed with the rib. It is explanatory drawing of the state which fitted the fitting convex part of the outer peripheral part of the seal diaphragm shown in FIG. 3, and the fitting groove of the outer peripheral part of the housing of a pressure switch, and was airtightly fixed. It is principal part sectional drawing which shows an example of the metal mold | die for carrying out injection molding of the seal diaphragm shown in FIG. FIG. 8A is an explanatory diagram when the seal diaphragm shown in FIG. 3 is molded by the mold shown in FIG. 7, and FIG. 8A is a molten silicon rubber when molding the fitting convex part of the inner peripheral edge of the seal diaphragm. FIG. 4B is an explanatory diagram of a state in which molten silicon rubber flows in and fills when molding the fitting convex portion of the outer peripheral edge portion of the seal diaphragm. It is sectional drawing which shows an example of the pressure switch which uses a diaphragm. FIG. 10 is a partially enlarged sectional view of the diaphragm shown in FIG. 9. It is principal part sectional drawing which shows an example of the metal mold | die for carrying out injection molding of the seal diaphragm shown in FIG. FIG. 11A is an explanatory diagram when the seal diaphragm shown in FIG. 10 is molded by the mold shown in FIG. 11, and FIG. 11A is a molten silicon rubber when molding the fitting convex portion of the inner peripheral edge of the seal diaphragm. FIG. 4B is an explanatory diagram of a state in which molten silicon rubber flows in and fills when molding the fitting convex portion of the outer peripheral edge portion of the seal diaphragm.

Explanation of symbols

1 Hollow housing as container 2 Housing 2a Port (gas introduction hole)
2b Outer peripheral edge 2c Fitting groove 2c 'Bottom 2d Pin-shaped protrusion 3 Cover 3a Port (gas introduction hole)
3b outer peripheral edge 3b 'lower surface 3d hole 4 switch 4a leaf spring 4b operating point 4c contact point 5 low pressure chamber 6 high pressure chamber 7 diaphragm 8 center plate 8a plunger 8b fitting groove 8b' bottom surface 8c rib 9 seal diaphragm 9a membrane 9b 9 Joint convex part 9b ', 9c' Bottom 10 Mold 11 Upper mold 11a Inlet 12 Lower mold 12a, 12b, 12c Recess (cavity)
12b ', 12c' Corners 12e, 12f, 12g, 12h Air trap 21 Diaphragm for pressure switch 22 Center plate 22a Upper surface 22b Lower surface 22c Plunger 22d Outer peripheral edge 22e Fitting groove 22e 'Bottom 22f Rib 23 Sealing diaphragm 23a Membrane 23b Peripheral part 23c Outer peripheral part 23d, 23e Fitting convex part 23d ', 23e' Tip 30 Die 31 Upper mold 31a Inlet 32 Lower mold 32a, 32b, 32c Recess (cavity)
32b ', 32c' Bottom view A to I Diagrams schematically showing a case where molten silicon rubber flows into and fills the recesses 12b, 12c, 32b, 32c

Claims (4)

In the pressure switch diaphragm which defines the inside of the housing in two chambers and operates by the pressure difference between the two chambers to drive the switch accommodated in one of the chambers,
The diaphragm has a disc shape and has a center plate in which a fitting groove is formed on the entire outer periphery of the outer periphery, and an annular shape and is fitted and fixed in the fitting groove on the inner periphery on the entire periphery. And is fitted over the entire circumference in a fitting groove formed on the outer peripheral edge of the housing and formed on the outer peripheral edge of the housing. It consists of a seal diaphragm with a fitting convex part,
The tip of the fitting convex portion of at least one of the inner peripheral edge or the outer peripheral edge of the seal diaphragm facing the bottom surface of the center plate or the fitting groove of the housing has a curved surface with a convex cross section. Diaphragm for pressure switch.   The pressure switch diaphragm according to claim 1, wherein the seal diaphragm is formed of silicon rubber.   The pressure switch diaphragm according to claim 1 or 2, wherein the seal diaphragm is formed by injection molding. In the pressure switch that drives the switch housed in one of the chambers with a diaphragm that is defined by the pressure difference between the two chambers in the housing.
A pressure switch comprising the pressure switch diaphragm according to any one of claims 1 to 3.

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