JPH08184376A - Method for sealing container structure for oil - Google Patents

Abstract

(57) [Summary] [Purpose] A method for sealing an oil container-like structure in which oil does not seep out to the outer surface of the gasket even after a temperature cycle in which the engine is repeatedly operated and stopped. I will provide a. A silicone rubber gasket is provided between the mating surfaces 4, 4'of an oil container-like structure 1 which is divisible into at least two parts and has mating surfaces 4, 4'that face each other between the parts. In the sealing method described above, the protruding portion of the silicone rubber gasket 3 having a convex cross-sectional shape is fitted into the groove 5 provided on one of the mating surfaces, and compression-sealing is performed at a compression rate of 25 to 35%. A method for sealing a container-like structure for oil, which is characterized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for sealing an oil container-like structure, and more particularly, to a method for pressure-bonding and sealing a space between mating surfaces of an oil container-like structure using a silicone rubber gasket.

[0002]

2. Description of the Related Art Conventionally, organic synthetic rubbers such as acrylic rubber and nitrile rubber have been widely used as sealing materials for internal combustion engines such as rocker covers and oil pans. However, these organic synthetic rubbers have problems that they are inferior in heat resistance and oil resistance and are not suitable for on-site molding which is cost-effective. Therefore, attempts have been made to apply a silicone rubber that is easy to mold in situ and has excellent heat resistance and oil resistance. However, silicone rubber is used as a conventional gasket for internal combustion engine sealing material as shown in FIGS. 7 to 10, and has a square cross section, a flat plate shape, a daruma shape, or a convex shape with a hemispherical protrusion. Kaihei 4-1253
When the rocker cover is sealed by molding (see No. 61 publication) and subjected to a temperature cycle assuming repeated operation and stop of the engine, a sweating phenomenon that engine oil seeps out to the outer surface of the gasket is observed. It was Due to this sweating phenomenon, the appearance of the engine is contaminated, and it is difficult to distinguish it from oil leakage, which is a fatal defect leading to engine failure.

[0003]

The present inventors have arrived at the present invention as a result of extensive studies to solve the above problems. That is, the object of the present invention is to perform a temperature cycle assuming repeated operation and stop of the engine for a long period of time,
An object of the present invention is to provide a method for sealing an oil container-like structure in which oil does not seep out to the outer surface of the gasket.

[0004]

Means for Solving the Problem and Its Action The present invention is capable of being divided into at least two parts, and the space between the surfaces of the oil container-like structure having the surfaces facing each other between the parts. In the method of sealing with a silicone rubber gasket, a protrusion of a silicone rubber gasket having a convex cross section is fitted into a groove provided on one of the mating surfaces, and compression-sealed at a compression rate of 25 to 35%. The present invention relates to a method for sealing an oil container-like structure, which is characterized by the above.

In the present invention, the oil container-shaped structure has two mating surfaces facing each other for the purpose of enclosing and holding various oils such as lubricating oil, fuel oil, hydraulic oil and cooling oil. It means a container that can be divided into the above parts. Examples of such a container-like structure for oil include a combination of at least two separable parts such as an oil pan of an internal combustion engine of an automobile and a reaction container such as a rocker cover and a separable flask.

Hereinafter, the sealing method of the present invention will be described in detail with reference to the drawings. FIG. 1 shows an example of an oil container-shaped structure sealed by the sealing method of the present invention. The oil container-like structure 1 comprises a combination of a main body 2 and a lid portion 2 ', one of the mating surfaces 4 and 4'of the both is formed in a flat shape, and the groove 5 is provided in the other. . In FIG. 1, the groove 5 is provided on the mating surface 4 of the main body,
The groove 5 may be provided on the mating surface 4 ′ of the lid, and the mating surface 4 of the main body may be a flat surface. A silicone rubber gasket 3 having a convex cross section is press-fitted into the groove 5 by pressing,
The mating surfaces 4 and 4'are sealed. This mating surface 4,
The silicone rubber gasket 3 that seals between 4'is
For example, as shown in FIG. 2 to FIG. 3, the compression ratio with respect to the initial thickness of the gasket is 25 by performing the constant size tightening using the bolt and the spacer or the constant pressure tightening using the pressure spring.
It is pressure-bonded and held so as to be ~ 35%. This is because if the compressibility is less than 25%, the internal pressure of the gasket is too low, and the damming effect against oil seepage is small.
This is because if it exceeds 5%, the gasket is more likely to crack.

The cross-sectional shape of the silicone rubber gasket used in the sealing method of the present invention is T as shown in FIG.
Basically, it is a letter-shaped convex type. Also, those having rounded corners as shown in FIG. 5 or FIG. 6 and those having some shallow grooves at the bottom can be used. However, a hemispherical protrusion as shown in FIG. 10 is not included in the present invention.

The silicone rubber gasket used in the sealing method of the present invention may be molded in situ, or may be molded in advance using another mold. As the in-situ molding method, a mold disposed in advance on the container mating surface provided with one groove is used, and the thermosetting silicone rubber composition is injection-molded on the container mating surface and heat-cured ( Mo
ld In-Place Gasket (MIPG method), a method in which a thermosetting silicone rubber composition is applied to the mating surface of a container provided with one groove and then cured by heating (Cured In-Place)
Gasket; CIPG method).

The silicone rubber gasket used in the sealing method of the present invention has a hardness of 30 to 80 degrees measured according to the method specified in JIS K6301 (JIS.
A) is preferred. This is because if the hardness is less than 30 degrees, a sufficient sealing force cannot be obtained during compression, and 8
This is because if it exceeds 0 degrees, the stress on the container mating surface is large, which causes deformation or breakage of the container, or the gasket itself breaks. Further, in order to maintain a stable sealing property for a long time, the silicone rubber gasket preferably has a compression set of 50% or less after a lapse of 500 hours at a temperature of 150 ° C. with a compression rate of 25%.

The silicone rubber gasket used in the sealing method of the present invention is obtained by curing a thermosetting silicone rubber composition. For example, vinyl group-containing diorganopolysiloxane, silicon atom-bonded hydrogen atom-containing Addition reaction curable silicone rubber composition containing organopolysiloxane, silica fine powder and platinum catalyst as main components,
An organic peroxide-curable silicone rubber composition containing vinyl group-containing diorganopolysiloxane, silica fine powder and organic peroxide as main components can be mentioned. Among these, addition reaction-curable silicone rubber compositions are preferable. The viscosity of such a silicone rubber composition at 25 ° C. in the uncured state is 1,000 because of the ease of molding.
It is preferably in the range of to 20,000 poise, and the curing temperature is preferably in the range of 50 to 200 ° C.

According to the above-described sealing method of the present invention, the container for oil structure is pressure-bonded with a silicone rubber gasket having a convex cross-section at a compression rate of 25 to 35% to obtain a gasket. The internal pressure in the central part is high and a perfect seal can be obtained. As a result, a damming effect is exhibited in which the oil in the container-shaped structure does not pass through the gasket. Therefore, the oil container-like structure sealed by the sealing method of the present invention shows no oil bleeding to the outer surface of the gasket even after a temperature cycle assuming repeated operation and stop of the engine for a long period of time. Has the advantage.

[0012]

EXAMPLES The present invention will be described in detail below with reference to examples.
In the examples, the viscosity is a measured value at 25 ° C.

[0013]

Example 1 100 parts by weight of a dimethylvinylsiloxy group-capped dimethylpolysiloxane having a viscosity of 20 poise, 30 parts by weight of fumed silica having a specific surface area of 200 m ² / g, 50 parts by weight of silica powder having an average particle diameter of 5 μm, and silica surface treatment. Hexamethylsilazane (5 parts by weight) and water (2 parts by weight) were mixed as an agent until uniform, and further heat-treated under vacuum to prepare a liquid silicone rubber base. Next, 100 parts by weight of this liquid silicone rubber base was added with 1.5 parts by weight of a trimethylsiloxy group-blocked dimethylsiloxane / methylhydrogensiloxane copolymer (content of silicon atom-bonded hydrogen atoms: 0.8% by weight) as a crosslinking agent. Add 0.1 parts by weight of a complex of chloroplatinic acid and divinyltetramethyldisiloxane (0.4% by weight of platinum metal) as a catalyst and 0.05 parts by weight of 3,5-dimethyl-1-hexyne-3-ol as a curing inhibitor. Mix evenly to obtain a viscosity of 3,000
A 0 poise liquid silicone rubber composition was prepared. The liquid silicone rubber composition thus obtained is used to seal the aluminum test container 1'comprising the main body 2 and the lid portion 2'shown in FIG. As shown in FIG. 12, a reverse concave mold 6 was arranged. The liquid silicone rubber composition was injected into the space (cavity) formed between the main body 2 and the inverted concave mold 6 and heated at 150 ° C. for 5 minutes to be cured. Then, the reverse concave mold 6 was removed to obtain a silicone rubber gasket 3. The obtained silicone rubber gasket 3 has a width (a) of 7 mm and a height (b) of 5 mm as shown in FIG.
mm, the protrusion width (a ′) was 2.76 mm, and the protrusion height (b ′) was 2 mm. The silicone rubber gasket 3 has a hardness of 6
0 degree (JIS A), the compression set is 25%, and the compression set is 41% after 500 hours under the temperature condition of 150 ° C.
Lubricating oil for automobile 4-cycle engine at 150 ° C [Toyota Motor Corporation; Trade name: Castle Clean S
The volume change rate due to swelling after immersion in G (10W-30SG)] for 70 hours was + 20%. As shown in FIG. 11, the mating surface 4 ′ of the lid portion 2 ′ was superposed on the silicone rubber gasket 3 and tightened with a bolt to perform pressure-bonding sealing. Here, connection holes 8 and 9 for oil circulation are provided in the central portions of the container body 2 and the lid portion 2 '.
At this time, an aluminum spacer 7 having a thickness calculated in advance is sandwiched between the mating surfaces 4 and 4 ', and the compression ratio at the time of crimp sealing is 5%, 10%, 15%, 20%, 25%, 30%. ，
It was set to be 35% and 40%. Then, the lubricating oil was flowed in through the lower connecting hole 8 of the test container and was collected through the upper connecting hole 9 so that the inside of the container was circulated so that the lubricating oil was always filled. Here, this lubricating oil is heated by an oil bath to keep its temperature at 150 ° C.
It was performed for 6 hours and then allowed to cool for 8 hours. At this time, it takes about 1 hour after the heating starts until the lubricating oil reaches 150 ° C.
Time has passed, and the temperature of the lubricating oil after completion of cooling for 8 hours was about 35 ° C. This heating (16 hours) and cooling (8 hours) were set as one cycle, and this was repeated 40 times in total. At the end of cooling in each cycle, the presence or absence of oil seepage to the outer surface of the silicone rubber gasket was visually measured. The results of these measurements are shown in Table 1. For comparison, a silicone rubber gasket having a convex cross-section is used, and the cross-section has a width of 6 mm and a height of 8 mm.
The compression rate is 15%, 25%, 35% in the same manner as described above except that the gasket is made of a square silicone rubber of mm.
The presence / absence of oil bleeding on the outer surface of the gasket, which was pressure-bonded and sealed in%, was visually measured. The results of these measurements are shown in Table 1.

[0014]

[Table 1]

[0015]

The sealing method of the present invention can be divided into at least two parts, and a silicone rubber gasket is provided between the mating surfaces of the oil container-like structure having the mating surfaces facing each other between the parts. In the method of sealing with, the protruding portion of the silicone rubber gasket having a convex cross-section is fitted in the groove provided on one of the mating surfaces,
Since the oil container-like structure sealed by this method is pressure-bonded and sealed at a compression rate of 25 to 35%, the oil on the outer surface of the gasket is not subjected to the temperature cycle even if the engine is repeatedly operated and stopped for a long period of time. The feature is that no bleeding is seen. Such a sealing method of the present invention is particularly suitable as a sealing method for a rocker cover or an oil pan.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of an oil container-like structure sealed by a sealing method of the present invention.

FIG. 2 is a cross-sectional view showing a state (before compression) in which the silicone rubber gasket 3 seals between the mating surfaces 4 and 4 ′ in the sealing method of the present invention.

FIG. 3 is a silicone rubber gasket 3 for sealing between the mating surfaces 4 and 4 ′ in the sealing method of the present invention.
FIG. 6 is a cross-sectional view showing a state in which is compressed.

FIG. 4 is a cross-sectional view of a silicone rubber gasket used in the sealing method of the present invention.

FIG. 5 is a cross-sectional view of a silicone rubber gasket used in the sealing method of the present invention.

FIG. 6 is a cross-sectional view of a silicone rubber gasket used in the sealing method of the present invention.

FIG. 7 is a cross-sectional view showing a state in which a rectangular silicone rubber gasket seals between the container facing surfaces.

FIG. 8 is a cross-sectional view showing a state where a flat-plate type silicone rubber gasket seals between the container facing surfaces.

FIG. 9 is a cross-sectional view showing a state where a daruma-shaped silicone rubber gasket seals between the container mating surfaces.

FIG. 10 is a cross-sectional view showing a state in which a silicone rubber gasket having a hemispherical protruding portion seals between the container mating surfaces.

FIG. 11 is a cross-sectional view of an aluminum test container 1 ′ used in Example 1.

FIG. 12 is a cross-sectional view showing a state in which an inverted-concave mold 6 is arranged on the mating surface 4 of the main body in the first embodiment.

[Explanation of symbols]

1 Oil container-shaped structure 1'Aluminum test container 2 Main body 2'Lid part 3 Silicone rubber gasket 4 Main body mating surface 4'Lid mating surface 5 Groove 6 Mold 7 Aluminum spacer 8 Lower connecting hole 9 Upper connection hole

Front page continuation (72) Inventor Mike E. Cansulman 2-2 Chikusaigan, Ichihara, Chiba Toray Dow Corning Silicone Co., Ltd.

Claims (6)

[Claims] 1. A method of sealing with a silicone rubber gasket between the mating surfaces of an oil container-like structure which is divisible into at least two parts and has mating surfaces facing each other between the parts, A container structure for oil, characterized in that a protruding portion of a silicone rubber gasket having a convex sectional shape is fitted into a groove provided in one of the mating surfaces and pressure-bonded and sealed at a compression rate of 25 to 35%. How to seal your body. 2. A thermosetting silicone rubber composition is injection-molded on the container mating surface using a mold in which the silicone rubber gasket is arranged on the container mating surface in which one groove is provided in advance. The method for sealing an oil container-like structure according to claim 1, wherein the method is a heat-curing and in-situ molding. 3. The silicone rubber gasket according to claim 1, wherein a thermosetting silicone rubber composition is applied to the container mating surface provided with one groove and then heat cured to be molded in situ. A method for sealing a container-like structure for oil. 4. The method for sealing an oil container-like structure according to claim 1, wherein a silicone standard gasket is used as the silicone rubber gasket. 5. The hardness of the silicone rubber gasket is J
The value measured according to the method defined in IS K6301 is 30 to 80 degrees (JIS A), and the compression rate is 2
The method for sealing an oil container-like structure according to claim 1, wherein the compression set after 50 hours at a temperature of 5% and 150 ° C. is 500% or less. 6. The method for sealing an oil container-shaped structure according to claim 1, wherein the silicone rubber gasket is obtained by curing an addition reaction-curable silicone rubber composition.