JP2914042B2 - Manufacturing method of packing member by screen printing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a packing member by screen printing rubber on the surface of the member.

[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. The heat-insulating member with packing is, for example, a member obtained by attaching an asbestos joint sheet to the surface of a phenolic resin molded product. It is manufactured through a number of processes of stamping a product shape onto the surface of a heat insulating member with an adhesive. Such a heat-insulating member with packing is interposed between members constituting a carburetor of an automobile, and is fastened and fixed with bolts, thereby performing functions of heat insulation and airtightness. In addition, asbestos is not used due to safety and health regulations, and is shifting to a joint sheet using inorganic fibers other than asbestos, such as glass, or aromatic polyamide fibers instead of asbestos as a base material. By the way, automobile engines are lighter (thinner, material change to aluminum)
As a result, the rigidity is reduced and the expansion / contraction fluctuation is increased. In addition, 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] However, the heat insulating member with packing to which the above-mentioned joint sheet is attached cannot sufficiently satisfy the above-mentioned demands. That is, when the heat-insulating member with the packing interposed between the mating members is tightened with bolts, the packing reduces the thickness due to the pressure and adheres closely to the mating member. It must be large enough (typically a tightening torque of 150-200 kg · cm with 8 mm diameter bolts). 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 on which the heat insulating member is interposed is small,
At a position away from the tightening bolt, the mating member is deformed (curved) without reducing the thickness of the packing,
Adhesion with packing deteriorates. FIG. 5 shows this state. The thickness of the packings 2 and 2 ′ (joint sheet) attached to both surfaces of the heat insulating member 1 is reduced near the tightening bolt 3, but the tightening bolt At the center between the bolts apart from 3, the mating member 4 is more deformed. Therefore, the surface pressure on the packing is also small at the center between the tightening bolts and is not uniform (the length of the arrow of the surface pressure distribution indicates the magnitude of the surface pressure).

[0004]

The use of packing having a uniform thickness as described above is disadvantageous because the distribution of high and low contact pressures can be obtained. If the thickness of the packing where the surface pressure is high is reduced in advance, the surface pressure of each part when finally tightened can be equalized, but in the conventional method such as attaching a joint sheet, the packing thickness is It is difficult to change it in each part as needed. The problem to be solved by the present invention is to make it possible to easily change the thickness of the packing in each part as needed when manufacturing a member with a packing.

[0005]

The production method according to the present invention comprises:
A rubber packing is integrally formed on the surface of the member by screen printing rubber on the surface of the member.
The screen used for printing is made of plastically deformable material.
Shall be. Where you want to reduce the packing thickness
The thickness of the screen is reduced by press molding, and the thickness of the screen is changed depending on the location. The part to reduce the thickness of the screen, for example,
Use a packing with a uniform thickness to correspond to a place where the surface pressure increases when tightened. In addition, the packing is made to correspond to the convex portion of the mating member with which the packing comes into contact.

[0006]

In the manufacturing method according to the present invention, a thin packing which cannot be achieved by pasting a joint sheet can be integrally formed on the surface of the member by screen printing, but the printing thickness becomes thin in a thin portion of the screen. In addition, the thickness of the packing can be made thinner than other parts. When adjusting the thickness of the screen by press molding, the cross-sectional shape of the line forming the screen becomes flat in the pressed part, and the thickness and the opening area of the screen become smaller. It is convenient for thinning.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In carrying out the production method according to the present invention, silicone rubber, N
BR, fluorosilicone rubber and the like can be appropriately selected. The printing thickness of the rubber is suitably about 0.05 to 0.3 mm. By performing heat treatment after printing, the screen-printed rubber is baked on the surface of the member.
A temperature of 150 ° C. for 5 to 10 minutes is suitable. If the temperature is increased, the time can be shortened. However, if the printing is thick, the surface may be swollen. The screen is
The one composed of steel wire, nylon thread, etc. is appropriately selected.

Hereinafter, embodiments of the present invention will be described in detail. FIG. 4 shows a surface pressure distribution when the heat insulating member 1 made of phenol resin having uniform packing formed on both surfaces is interposed between members constituting a carburetor of an automobile and tightened and fixed with bolts. (The length of the arrow indicates the magnitude of the surface pressure). It can be seen that the surface pressure is high around the hole 5 for the tightening bolt, and the surface pressure decreases as the distance from the hole 5 increases. Therefore, a screen 6 made of stainless steel and having a sectional shape as shown in FIG.
(Stainless steel wire has a circular cross section) was pressed by press dies 7, 7 'having a cross section having a concavo-convex shape reverse to the concavo-convex shape in FIG. As shown in FIG. 1 (b), in the portion pressed by the convex portion of the press die, the cross-sectional shape of the stainless wire becomes flat according to the height of the convex portion, and the thickness of the screen becomes thin. . The flattening of the cross section of the stainless wire also reduces the opening area of the screen, and the thickness of the packing 2 printed using such a screen is the thinnest around the hole 5 for the tightening bolt, It gets thicker as you get away from it. FIG. 2 shows a sectional shape of the formed packing 2. The thinnest area around hole 5 is 0.02m
m, the thickest part away from the hole is 0.07 mm. FIG. 3 shows the surface pressure distribution when the heat insulating member with packing shown in FIG. 2 is tightened and fixed, and the surface pressures of the respective parts are equal. If the thickness of the screen is adjusted with a press, the thickness of the packing will be partially reduced because the cross-sectional shape of the lines forming the screen will be flattened and the opening area of the screen will be reduced accordingly. Above is very convenient. Further, when the cross-sectional shape of the filament becomes flat, the filament meshes at the intersection, so that it is possible to prevent the screen from being misaligned, and the screen can be used for a long time.

When a screen is made of a thermoplastic resin such as nylon thread, it is sufficient to apply heat when adjusting the thickness by pressing. For adjusting the thickness of the screen, a means for partially polishing the screen may be used instead of the pressing means. Polishing is preferably performed on the surface in contact with the member to be printed, and polishing on the squeegee side is not preferable because the life of the squeegee is shortened. Although the thickness of the packing formed on the member is easily adjusted in response to the above, the method according to the present invention is also applied to a case where a groove for fitting an O-ring is formed in a mating member. it can. That is, if the thickness of the printing screen is kept unchanged at the portion corresponding to the groove and the other portion is pressed and thinned, a flat packing integrated with the O-ring can be easily formed on the surface of the member. Can be formed.

[0010]

As described above, in the manufacturing method according to the present invention, the thickness of the packing formed integrally with the member is partially changed by a simple method of partially reducing the thickness of the screen. Can be. If the pressing means is used as a means for partially reducing the thickness of the screen, the effect of partially reducing the packing is large, and the service life of the screen itself can be extended.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a printing screen used in a method according to the present invention.

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

FIG. 3 is an explanatory diagram of a surface pressure distribution of packing of the member with packing in FIG. 2;

FIG. 4 is an explanatory diagram of the surface pressure distribution when the thickness of the packing is uniform in FIG.

FIG. 5 is a side view of a conventional member with a packing in use and an explanatory diagram of a surface pressure distribution of the packing.

[Explanation of symbols]

 1 is a member 2, 2 'is a packing 3 is a fastening bolt 4 is a mating member 5 is a hole for a fastening bolt 6 is a screen 7, 7' is a press die

Claims (3)

(57) [Claims] 1. A rubber packing rubber on the surface of the member to the member by screen printing to a method of integrally formed, as a screen to be used for printing, plastic
Manufacture of members with packing by screen printing, characterized by using a screen made of a deformable material , reducing the thickness of the packing by press molding at places where the thickness is desired to be reduced, and using screens with different thicknesses at different places Law. 2. The screen printing according to claim 1, wherein the thickness of the screen is reduced corresponding to a portion where the surface pressure is increased when the packing is tightened by using a packing having a uniform thickness. Method for producing a member with packing according to the above. 3. The method for manufacturing a member with a packing by screen printing according to claim 1, wherein the thickness of the screen is reduced corresponding to the location of the projection of the mating member with which the formed packing contacts.