JP3714635B2 - Impervious diaphragm - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an impermeable diaphragm, and more particularly to an inexpensive diaphragm that does not transmit oil and the like, has good oil resistance and heat resistance, has a reduced number of parts, is easy to install, and is inexpensive.
[0002]
[Prior art and problems]
Conventionally, as an impermeable diaphragm, a sheet diaphragm using only a polyimide resin having good low temperature resistance and heat stress resistance is known. For example, when used for a diaphragm in an automotive hydraulic switch, the hydraulic pressure of the engine Due to the repetition due to the fluctuation of the above, there was a drawback that it was easily damaged by fatigue and lacked durability.
[0003]
In order to remove such defects, for example, as shown in FIG. 3, a diaphragm 1 manufactured by bonding heat-resistant and oil-resistant rubber sheets 3 to both surfaces of a polyimide film 2 by a method such as topping or gluing is provided. It is known (Japanese Utility Model Publication No. 3-63883).
[0004]
When such a diaphragm 1 is incorporated in the pressure switch as described above, O-rings 4 and 5 must be separately mounted around the outer peripheral portion and the central mounting hole of the diaphragm, and the number of parts is reduced. Not only did it increase, but it also had the drawback of requiring a lot of work, and the cost was high.
[ 0005 ]
The present invention has been made to solve the above-described problems, and provides an impermeable diaphragm that has good heat resistance and oil resistance, has a reduced number of parts, is easy to install, and is inexpensive. With the goal.
[ 0006 ]
[Means for solving problems]
In order to solve the above-mentioned problems, the impermeable diaphragm according to the present invention has a flange portion and a membrane portion rising from the flange portion, and the flange portion and the membrane portion are heat and oil resistant on both sides of the aramid film. A non-permeable diaphragm having a thickness of 0.016 to 0.075 mm, a rising height of the film portion of 5 mm or less, and a thickness of the rubber layer. The length is 0.05 to 0.3 mm, and a bead portion is provided around the flange portion.
[ 0007 ]
It impermeable diaphragm of the present invention is an impermeable diaphragm to have a the membrane portion has risen from the flange portion and the flange portion, the diaphragm is heat resistant aramid film, provided with oil-resistant rubber layer It is characterized by.
[ 0008 ]
According to the present invention, since the bead portion is formed on the outer periphery of the flat diaphragm main body, it is possible to omit the mounting of the O-ring, and it is easy to incorporate into a pressure switch and the number of parts. Therefore, an inexpensive diaphragm can be provided.
[ 0009 ]
Since the polyimide film 2 has low heat shrinkage and does not have stretchability, the polyimide film 2 can be provided only by the method of sticking the rubber sheet 3 as described above. Furthermore, as described above, heat shrinkability and stretchability are provided. From this point of view, there is a drawback that only flat so-called flat diaphragms can be manufactured. According to the impervious diaphragm of the present invention, since an aramid film having heat resistance characteristics similar to that of a polyimide film and having elasticity and heat shrinkage is used, a rubber layer is formed on the aramid film in the mold. Can be provided. This makes it possible to mold a so-called dish-shaped diaphragm with a rising film portion, and has the advantage of increasing the swing stroke without impairing other characteristics.
[ 0010 ]
DETAILED DESCRIPTION OF THE INVENTION
Figure 1 is a cross-sectional view of an impermeable diaphragm, diaphragm main body 1 As apparent from this figure, is in heat resistance to a flat form sheet-like film 2 was provided rubber layer 3 of the oil-resistant structure It is a so-called flat diaphragm. In this embodiment, an upper rubber layer 31 and a lower rubber layer 32 are provided, and the rubber layer 3 may be provided on one side depending on the method of use.
[ 0011 ]
Since it can be manufactured by a mold as described above , the seal portion of the mounting portion can be formed integrally. That is, as shown in FIG. 1, a bead portion 33 is provided integrally with the outer periphery of the lower rubber layer 32 of the diaphragm body 1. A bead portion 34 is also provided in the lower rubber layer 32 around the mounting hole 13. A bead portion may be provided on the opposite side of the beads 33 and 34 (33 ′, 34 ′). By integrally forming the beads 33 and 34 in this way, it is possible to omit the mounting of the O-ring, and it is easy to incorporate into the pressure switch and the like, and the number of parts can be reduced, so that it is inexpensive. Can provide a simple diaphragm.
[ 0012 ]
FIG. 2 is a cross-sectional view of the impermeable diaphragm of the present invention. As is clear from this figure, the diaphragm main body 1 according to the present invention has a flange portion 11 for incorporation in a pressure switch or the like. 11 has a film part 12 rising from 11. A mounting hole 13 is formed at the center of the film portion 12 to form a so-called dish-shaped diaphragm.
[ 0013 ]
In this embodiment of the present invention, the diaphragm 1 has a cross-sectional structure in which the rubber layer 3 is provided on both sides of the aramid film 6 and is molded by a mold to provide the rubber layer 3. . In this embodiment, the rubber layer 3 is provided on both sides of the upper rubber layer 31 (the rubber layer in the rising direction) and the lower rubber layer 32, but may be provided on either side.
[ 0014 ]
The aramid film 6 is a film having good heat resistance and capable of being molded at 200 ° C. or less (having stretchability and heat shrinkability) as described above, and via a phenolic adhesive in the mold. The rubber layer 3 can be molded and vulcanized and bonded satisfactorily.
[ 0015 ]
The thickness of the film as described above is preferably 0.016 to 0.075 mm. If it is less than 0.016 mm, it will be difficult to exhibit required performance such as heat resistance and impermeability. On the other hand, if it is thicker than 0.075 mm, the rigidity of the product will increase, making it unsuitable for use.
[ 0016 ]
On the other hand, the heat-resistant and oil-resistant rubber layer formed on both sides or one side of the film is not basically limited in the present invention, and can be functionally determined in consideration of the characteristics required of the diaphragm. . For example, a heat-resistant and oil-resistant rubber layer such as nitrile rubber, fluorine rubber or hydrin rubber can be provided. The rubber layer preferably has a thickness of 0.05 to 0.3 mm. If the thickness is less than 0.05 mm, the strength may be insufficient. On the other hand, if it exceeds 0.3 mm, the rigidity may increase and the product characteristics may be impaired. However, the rigidity is reduced by the size of the outer diameter. It is not limited because it can.
[ 0017 ]
Furthermore, the rising height h of the film part 12 is 1: h = 100: 15 or less with respect to the outer diameter L, or preferably 5 mm or less. This is because if it exceeds 5 mm, molding becomes difficult.
[ 0018 ]
Since the dish-shaped diaphragm of the present invention is manufactured using a mold as described above, the seal portion of the mounting portion can be integrally formed. That is, as shown in FIG. 2, a bead portion 33 is integrally formed around the outer periphery of the lower rubber layer 32 of the diaphragm body 1. A bead portion 34 is also provided in the lower rubber layer 32 around the mounting hole 13. A bead portion may be provided on the opposite side of the beads 33 and 34 (33 ′, 34 ′). By integrally forming the beads 33 and 34 in this way, it is possible to omit the mounting of the O-ring, and it is easy to incorporate into the pressure switch and the like, and the number of parts can be reduced, so that it is inexpensive. Can provide a simple diaphragm.
[ 0019 ]
(Reference Example 1)
A flat diaphragm having a diameter of 20 mm as shown in FIG. 1 was produced. That is, a phenolic adhesive is applied to both sides of a 0.016 mm thick polyimide film in the form of a flat circular sheet, the height of the bead portion provided at the outer periphery is 2 mm, and the height of the bead around the mounting hole 13 is 1. It was placed in a mold of 2 mm and charged with unvulcanized hydrogenated NBR, pre-molded, a polyimide film was inserted in the center, and heated and pressurized to vulcanize to produce a flat diaphragm. The thickness of the rubber layer was 0.07 mm.
[ 0020 ]
The bead portions 33 and 34 were well formed, and it was possible to omit the mounting of the O-ring, which facilitated incorporation into a pressure switch or the like and reduced the number of components.
[ 0021 ]
[ Example 1 ]
A dish-shaped diaphragm having a diameter of 20 mm as shown in FIG. 2 was produced. The rising height h was 3 mm, the thickness of the aramid film was 0.02 to 0.07 mm, and the thickness of the hydrogenated NBR rubber layer was 0.07 mm. The height of the bead portion 33 was 2 mm, and the height of the bead portion 34 around the mounting hole 13 was 1.2 mm.
[ 0022 ]
After abrading the aramid film in advance to a dish mold, a phenolic adhesive is applied to both sides, and uncured hydrogenated NBR is charged into the mold, and after pre-molding, the aramid film is charged and heated under pressure. Sulfurized to produce a dish-shaped diaphragm.
[ 0023 ]
On the other hand, when a polyimide film having the same thickness was used, a conventional flat diaphragm having the same thickness of the same fluororubber layer was used, and a swing stroke was measured, it was 0.5 mm. On the other hand, in the present invention, the swing stroke is 5 mm, and it can be seen that it is greatly improved.
[ 0024 ]
【The invention's effect】
As described above , according to the present invention, since an aramid film having heat resistance similar to that of a polyimide film and having a stretch property and a heat shrink property is used, the aramid film is used to some extent in the mold. It can be deformed. For this reason, not only a flat diaphragm but also a so-called dish-shaped diaphragm having a raised film portion can be molded, and there is an advantage that the swing stroke is increased without impairing other characteristics. Further, if the bead portion is formed, it is possible to omit the O-ring, and it is easy to incorporate into the pressure switch and the like, and the number of parts can be reduced, so that an inexpensive diaphragm can be provided.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a reference example .
FIG. 2 is a sectional view of an embodiment of the present invention. FIG. 3 is a sectional view of a conventional diaphragm.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Diaphragm 11 Flange part 12 Membrane part 2 Polyimide film 3 Rubber layer 31 Upper rubber layer 32 Lower rubber layer 33 Bead part 34 Bead part 6 Aramid film

Claims (2)

A flange portion and a membrane portion rising from the flange portion, the flange portion and the membrane portion being an impermeable diaphragm in which a heat-resistant and oil-resistant rubber layer is provided on both sides of the aramid film, The film has a thickness of 0.016 to 0.075 mm, the rising height of the film portion is 5 mm or less, and the rubber layer has a thickness of 0.05 to 0.3 mm. An impermeable diaphragm characterized in that a portion is provided. The impermeable diaphragm according to claim 1 , further comprising a mounting hole at a center of the film portion and a bead portion around the mounting hole.

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