JPH112330A - Manufacture of member with packing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently easily manufacture a member with packing of good air-tightness by screen printing, by using hydrogenation nitrile butadiene rubber having heat/gasoline resistance and good restoration relating to compressive deformation. SOLUTION: Hydrogenation nitrile butadiene rubber with viscosity adjusted to 2 to 5 million cP is screen printed in a surface of a member, heat treating is performed, in the surface of the member, a packing layer is integrally formed. In a part with the packing layer desired thick, corresponding to this part, a lining 6 of desired thickness is applied to a screen 5, a part thereof is floated from a printing surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a member with a packing provided with a packing layer made of hydrogenated nitrile / butadiene rubber.

[0002]

2. Description of the Related Art As a member with a packing, there is a heat insulating member with a packing used between members constituting a carburetor of an automobile. 2. Description of the Related Art In automobile engines, rigidity is reduced and expansion and contraction fluctuations are increased due to weight reduction (reduction in thickness and material change to aluminum). Also,
Due to miniaturization (miniaturization and reduction of parts), the size of bolts to which the heat insulating member is attached and tightened is reduced or the number of bolts is reduced. In addition, the temperature has become high due to the high output (turbocharger). Under such circumstances, the demand for improving the airtightness of the heat-insulating member with packing has been further increased.

[0003] When a heat insulating member with a packing interposed between members is tightened with a bolt, the packing layer is reduced in thickness by the tightening pressure and is brought into close contact with a mating member. However, in order to reduce the thickness of the packing layer, a tightening torque is required. Must be sufficiently large (typically a tightening torque of 150 to 200 kg · cm with an 8 mm diameter bolt). However, as described above, if the number of tightening bolts is small and the pitch between the bolts is long, or if the rigidity of the mating member with the heat insulating member interposed therebetween is low, the thickness of the packing layer at a position away from the tightening bolts increases. Without being reduced, the mating member is deformed (curved), and the adhesion to the packing layer is deteriorated. FIG. 4 shows this state. The packing layers 2 and 2 ′ (joint sheets) attached to both surfaces of the heat insulating member 1 are reduced in thickness in the vicinity of the tightening bolt 3, but are tightened. At the center between the bolts away from the bolt 3, the mating member 4 is more deformed. Therefore, the surface pressure on the packing layer is also small at the center between the tightening bolts and is not uniform. (The length of the arrow in the surface pressure distribution indicates the magnitude of the surface pressure).

[0004] In order to cope with the above, there has been proposed a method of manufacturing a member with a packing in which a packing layer is formed by screen printing. A method of forming a packing layer by screen printing a rubber material using a screen with a partially reduced thickness, corresponding to places where the surface pressure increases when a uniform thickness packing layer is formed. is there. A screen having a partially reduced thickness is prepared by pressing a predetermined portion of a screen made of a plastically deformable material to reduce the thickness. Further, as another method, there is a method of forming a packing layer having an increased thickness on the first rubber coating layer by partially applying the second coating corresponding to a portion where the surface pressure becomes low. is there.

[0005]

However, in the above conventional method, in the former method, when the size of the member is long, the screen is pressed to partially change the thickness. A mold corresponding to is required. In the latter case, rubber is applied to the surface of the member and heat treatment is performed, and the application and heat treatment are repeated once more, which requires a lot of man-hours and is inefficient.

[0006] The problem to be solved by the present invention is to prevent heat and heat.
Uses hydrogenated nitrile-butadiene rubber, which has gasoline resistance and has good resilience to compression deformation, and provides a packing with good airtightness even if the mating member has low rigidity or the pitch between the tightening bolts is long. And efficient and simple manufacture by screen printing.

[0007]

In order to solve the above-mentioned problems, the production method according to the present invention has a viscosity of 2,000,000 to 5,000,000.
The hydrogenated nitrile-butadiene rubber adjusted to cp is screen-printed on the surface of the member and heat-treated to form a packing layer integrally on the surface of the member. In a portion where the packing layer is desired to be thickened, the screen is lined with a predetermined thickness corresponding to the portion, and the portion is floated from the printing surface. The portion where the backing of the screen is thickened is, for example, a portion corresponding to a portion where the surface pressure becomes low when a packing layer having a uniform thickness is formed and tightened with bolts. The viscosity of the hydrogenated nitrile-butadiene rubber to be screen printed is preferably 3 to 4 million cp.
Adjust to A packing layer having a thickness of 0.2 to 0.3 mm can be formed by one printing.

In the manufacturing method according to the present invention, a screen for printing is provided with a predetermined backing, and a hydrogenated nitrile-butadiene rubber having a predetermined viscosity is screen-printed on the surface of the member, so that the surface pressure can be adjusted. The thick packing layer can be easily formed by one printing. Man-hours such as adjusting the thickness of the screen for printing by press molding and repeating rubber printing or coating twice are not required.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The viscosity of a hydrogenated nitrile-butadiene rubber to be screen-printed is adjusted by diluting with a solvent. Isophorone is suitable as the solvent. It is necessary that the viscosity be 2,000,000 to 5,000,000 cp in order to secure a coating thickness of 0.2 to 0.4 mm by one screen printing. By adjusting the viscosity to 3 to 4 million cp, a packing layer having a thickness of 0.2 to 0.3 mm can be formed more favorably by one printing.

The thickness of the coating by screen printing is appropriately determined based on the size of the tightening bolts, the pitch between the bolts, the rigidity of the mating member, and the like, but a thickness of 0.2 to 0.4 mm can be set as described above. is there. By performing a heat treatment after printing, the screen-printed rubber is baked on the surface of the member. The condition is suitably at 160 ° C. for 2 hours.

As the screen for printing, a screen made of steel wire, nylon thread or the like is appropriately selected. The places where the thickness of the packing layer is set to be somewhat thicker are not only the part distant from the fastening position but also the periphery of the liquid or gas circulation hole provided in the member. The formation of the packing layer may be performed not only on the entire surface of the member, but also only at a necessary portion, for example, only around a circulation hole provided in the member. Even when the packing layer is formed only around the circulation hole, the packing layer is changed in thickness according to the level of the surrounding surface pressure. Thereby, the airtightness around the circulation hole can be improved.

[0012]

EXAMPLE As shown in FIG. 1 (a), a screen 5 made of a nylon thread with a portion not subjected to printing being masked is prepared, and a back surface having unevenness opposite to the unevenness of the surface pressure distribution is prepared. Tension 6 is applied. As shown in FIG. 1 (b), the space provided with the backing 6 has a space below the screen 5, and the screen rises from the surface of the member to be printed. Using such a screen, as shown in FIG. 2, a hydrogenated nitrile-butadiene rubber diluted with isophorone is screened on both surfaces around a circulation hole 7 provided in the heat insulating member 1 made of phenol resin having a long dimension. Coated by printing. And one
The vulcanization was performed at 60 ° C. for 2 hours to form a packing layer 2 having a width of 2.5 mm (design value). The thickness of the packing layer 2 is
The thinnest hole (design value: 0.20 mm) near the hole 8 for the tightening bolt, and the thicker hole 8
Thickest at the furthest point from the design (design value 0.25m
m).

In the above, the maximum film thickness applicable by one screen printing was examined while changing the viscosity of the isophorone-diluted hydrogenated nitrile-butadiene rubber. The result is shown in FIG.
Shown in By increasing the viscosity to 2 million cp or more, 0.2
Thick coating of mm or more can be performed in one printing operation. Table 1 shows the results of airtightness tests of packing layers formed by screen printing hydrogenated nitrile-butadiene rubbers of various viscosities. In the airtight test, the member 1 was sandwiched between the model flanges, and fixed by passing a bolt through a hole 8 for a tightening bolt, supplying air at a pressure of ² kg / cm ² to the inside of the hole 8 in water, and leaking into the water. The amount of air coming out per minute was measured. 3 air leaks
Those at 0 cc / min or less were regarded as good. From Table 1, the viscosity is 2
It can be understood that the airtightness is good by screen-printing a hydrogenated nitrile-butadiene rubber of 100 to 5 million cp.

[0014]

[Table 1]

Next, a packing layer is formed by screen-printing hydrogenated nitrile-butadiene rubber of various viscosities, and the workability of screen printing (remaining adhesion of rubber to the screen: residue, design of formed packing layer) Table 2 shows the results of a survey on the spread from the price range: sauce). From Table 2, it can be understood that by setting the viscosity of the hydrogenated nitrile-butadiene rubber to 2 to 5 million cp, the printing workability can be improved, and further to 3 to 4 million cp to further improve the printing workability. The evaluation indices in the table are as follows. Residual eyes ◎: None ○: Available (no effect on airtightness) ×: Available (no effect on airtightness) Sagging ◎: Less than 5% ○: Less than 5-10% △: Less than 10-20% ×: 20% that's all

[0016]

[Table 2]

[0017]

As described above, in the manufacturing method according to the present invention, the thickness of the packing layer integrally formed on the member is partially changed by a simple method of lining the screen with a predetermined thickness. be able to. Then, by specifying the viscosity of the hydrogenated nitrile-butadiene rubber to be screen-printed, a packing layer having good airtightness can be formed with good workability.

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view of a printing screen used in a method according to the present invention.

FIG. 2 is a perspective view of a main part of a member with a packing manufactured by a method according to the present invention.

FIG. 3 is a curve diagram showing the relationship between the viscosity of hydrogenated nitrile-butadiene rubber and the maximum film thickness that can be applied in a single application.

FIG. 4 is a side view and an explanatory diagram of a surface pressure distribution of a packing layer in a use state of the member with packing.

[Explanation of symbols]

 1 is a member 2, 2 'is a packing layer 3 is a fastening bolt 4 is a mating member 5 is a screen 6 is a backing 7 is a circulation hole 8 is a hole for a fastening bolt

Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI // C09D 11/10 C09D 11/10 C09K 3/10 C09K 3/10 Z

Claims (3)

[Claims] When forming a packing layer on the surface of a member by screen printing a rubber material, at a place where the packing layer is desired to be thickened, the screen is lined with a predetermined thickness corresponding to the place, and the part is formed. As a rubber material for screen printing so that it floats from the surface of the member, it has a viscosity of 20
A method for producing a member with a packing by screen printing, wherein a hydrogenated nitrile-butadiene rubber adjusted to 100,000 to 5,000,000 cp is used. 2. A method according to claim 1, wherein a packing layer having a uniform thickness is formed and a surface pressure is reduced when the packing layer is tightened with a bolt.
2. The method according to claim 1, wherein the thickness of the backing of the screen is increased. 3. The viscosity of the hydrogenated nitrile-butadiene rubber is adjusted to 3,000,000 to 4,000,000 cp, and 0.2 times per printing.
The method for producing a member with a packing by screen printing according to claim 1 or 2, wherein a packing layer having a thickness of 0.3 mm is formed.