JP2923657B2 - Seal structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an FIPG or the like which seals between the sealing surfaces by interposing a room-temperature-curable liquid rubber on sealing surfaces facing each other such as various automobile parts and electric parts. According to the sealing structure, in particular, by forming a unique structure between the sealing surfaces, the liquid rubber is improved in the sealing property at the time of final curing, the liquid resistance is also improved, and the followability to the movement of the sealing surface and the sealing are improved. The present invention also relates to a seal structure such as FIPG which improves workability of a surface and as a result, maintains high reliability and workability.

[Conventional technology]

Conventionally, the seal structure shown in FIG. 6 and FIG. 7 is known. In this method, a ridge 2 and a concave ridge 3 are provided adjacent to a part of the sealing surface 1, and another sealing surface 4 facing the sealing surface 1 is bolted via a liquid gasket 5 as shown in FIG. This is a tightening structure for improving pressure resistance and gasket breakage at the time of final curing of the liquid gasket 5. (Japanese Patent Publication No. 55-35576).

Further, as shown in FIG. 8 and FIG. 9, a seal structure in which a groove 7 is cut in the seal surface 1 is also known. This is a structure in which another sealing surface 4 facing the sealing surface 1 is tightened by a bolt 6 via an adhesive 5 as shown in FIG.

Further, as shown in FIGS. 10 and 11, there is also known a seal structure in which a notch 8 is cut in a seal surface 1.
This is a structure in which another sealing surface 4 facing the sealing surface 1 is tightened by a bolt 6 via an adhesive 5 as shown in FIG.

In FIGS. 8 to 11, the use of the groove 7 or the notch 8 prevents adhesion peeling and cohesive failure when the relative movement of the sealing surface is large.

[Problems to be solved by the invention]

In general, a seal structure such as FIPG has a structure in which a room-temperature-curable liquid rubber such as silicone or urethane is interposed on a seal surface.

Since a leak test is performed before the sealant is cured on the assembly line, pressure resistance during final curing is required. For this purpose, the clearance of the sealing surface must be as small as possible.

The vertical direction of the seal surface due to vibration, temperature difference, internal pressure, etc.
It is necessary to be able to follow horizontal movement and deviation. For this purpose, it is necessary to take a certain thickness of the sealant layer so that the sealant layer can be followed by elongation.

Since a liquid such as oil, which is highly degradable with respect to the sealant, is often sealed, a metal touch structure in which the sealing surfaces directly contact each other as much as possible, making the contact area with the seal liquid small and resistant to deterioration Need to be

FIPG sealants are generally one-part, and gradually cure from the surface by reacting with moisture and oxygen in the atmosphere.Therefore, the outer periphery of the seal surface is a metal touch structure. Takes time. For this reason, it is better that the outer peripheral portion is opened as much as possible and the gap is large.

 Processing of sealing surface is easy.

If the sealant protrudes largely on the inner side (inside) of the seal surface, the sealant may be torn off, causing troubles such as clogging. Therefore, protrude the inner side as much as possible.

The sealant must adhere well to the seal surface and follow the movement of the seal surface and deformation due to internal pressure.

Normally, high seal reliability is obtained due to adhesiveness and elongation, and parts can be easily disassembled without scratching during maintenance replacement of parts.

Looking at the prior art from the above conditions, first, the method of FIG. 6 and FIG. 7 in which the protrusion and the recess are adjacent to the flange is certainly effective in coexisting the pressure resistance and the followability at the time of final curing, Since the inner surface of the seal surface is relatively open, the liquid resistance such as oil resistance is inferior, and it takes time for the sealant in the recess to harden. Although this is not a problem with stamped parts, it takes time and effort to make this structure with aluminum cut parts. In addition, when the sealant is applied to the projections, the sealant tends to protrude to the inner side, and the maintenance decomposability is not good. Further, the case of the grooved flange as shown in FIGS. 8 and 9 also has the same disadvantage as the above-mentioned uneven flange. 10 and 11
The notched flange shown in the figure also has a drawback that the followability with respect to the movement of the flange is not obtained in addition to the drawbacks observed in the above-mentioned uneven flange.

Therefore, an object of the present invention is to provide a seal structure such as FIPG that seals between the sealing surfaces by interposing a room-temperature-curable liquid rubber on the mutually facing sealing surfaces of an engine block and an oil pan of an automobile. With this structure, the sealing performance of the liquid rubber when it is not cured is improved, the liquid resistance is improved, and the followability to the movement of the sealing surface and the working of the sealing surface are also improved. Another object of the present invention is to provide a seal structure such as FIPG which maintains high reliability and workability.

[Means for solving the problem]

In order to achieve the above object, according to the present invention, in a seal structure for sealing between the sealing surfaces by interposing a room-temperature curable liquid rubber between mutually facing sealing surfaces of an engine block and an oil pan of an automobile, The seal inner side between the seal surfaces is in contact with each other and the outside is the opening clearance, the width of the surfaces that contact each other on the seal inner side is 1 mm or more, the thickness of the opening clearance is in the range of 1 mm to 5 mm, and The width of the opening clearance is larger than the width of the surfaces on the seal inner side that are in contact with each other.

 Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a perspective view of a combination of an engine block and an oil pan of an automobile, wherein 101 is an engine block, and 102 is an oil pan. These components are combined by attaching a sealing material 104 to a sealing surface 103 of an oil pan 102 and superposing a sealing surface (not shown) of an engine block 101 thereon. Although not shown, this sealing structure is configured with a sealing material 104 interposed between both sealing surfaces.

FIG. 2 is a cross-sectional view of the seal structure in the case where the seal structure of the present invention is adopted instead of the seal structure of FIG. 1, and shows a seal face 10a of the engine block 101 and the oil pan 102 facing each other. Room temperature curable liquid rubber 11 between 10b
To seal between the sealing surfaces 10a and 10b.

In the above-described sealing structure, the feature of the present invention is that the sealing surface
The seal inner side 12 between 10a and 10b is brought into contact with each other, and the outside 13 is used as an opening clearance 14. In the above structure, the room-temperature-curable liquid rubber 11 is mainly filled in the opening clearance 14. 15 is a bolt.

In order to make the outer side 13 between the sealing surfaces 10a and 10b an opening clearance 14, for example, as shown in FIG.
For example, the sealing surface 10a on the engine block 101 side may be a stepped structure a that opens in the direction of the outside 13, or as shown in FIG. 3, the sealing surfaces 10a, 10b
This is achieved by a structure such as a tapered structure b that opens between the seal inner side 12 and the outer side 13.

Assuming that only the followability of the stepped structure a in FIG. 2 is considered, it is sufficient for the movement of the sealing surface to occur during normal operation to be 0.5 mm or more. 1mm to 5 in terms of the thickness of the blade
mm, preferably in the range of 1.2 mm to 3 mm. For example, when calculating the lateral shift due to the temperature difference between the engine block and the oil pan in the case of a combination of aluminum and iron, if the flange circumference of the oil pan is 1400 mm and a temperature gradient of 100 ° C. occurs, 23 × 10 ^-6 (linear expansion coefficient of aluminum)
−12 × 10 ⁻⁶ (coefficient of linear expansion of iron) × 100 × 1400 = 1.54mm. When this is seen in the cross section of the sealing surface, about 0.77 mm of lateral movement has occurred about half, but this is because the thickness of the liquid rubber (sealant layer) is 2 mm and the sealant elongation is 300% In this case, as can be seen from the results shown in Table 1, the range is sufficient to follow.

Next, regarding the metal touch width on the seal inner side 12, the leak test pressure during assembly is 0.2 kgf / cm ^2.
1 mm or more, preferably 2 mm or more is enough to withstand the above. Also, considering the oil resistance, the seal surface of the conventional metal touch structure is more than 100,000 km, and the discoloration of the sealant layer is 1 m from the inner side even in the oil pan of an actual car
m, so that the width of the metal touch portion on the inner side is 1 mm or more, preferably 2 mm or more.

In addition, considering the sealing property at the time of uncuring, the leakage of the fluid from the parallel gap is expressed by the following equation.

Q = bh ³ · ΔP / 12ηl (1) where, Q: leakage amount, b: flange outer peripheral length, h: clearance, ΔP: pressure difference, η: viscosity of sealant, l: flange width It is.

Although Q may be small enough, if this is regarded as one constant A, other conditions can be set. A withstand pressure test using a conventional flat oil pan
When calculating the value of (Q), b = 1400 mm, h = 0.1 mm, η = 1400 P, 1 = 8 mm, and leak pressure ΔP = 1.0 kgf / cm ² .

Here, P = dyn · sec / cm ² = 1/980000 kgf · sec / cm ² A (Q) = 1.0 × 10 ⁻² (cm ³ / sec) The actual leak test pressure 0.2 kgf / cm using this A ^When the required flange width b at ² is calculated, b = A12ηl / h ³ · ΔP: O.16cm. If a flange width of 2 mm (seal surface width) is taken, sufficient unsealed sealing properties can be obtained.

Next, Examples 1 and 2 and Comparative Example 1 as shown in FIG.
A test piece with a cross section of ~ 4 and a length of 50m was subjected to a tensile test with a tensile tester at a speed of 10mm / min in the longitudinal and lateral directions, and the displacement up to the breaking point was measured as a follow-up property, and the results were shown. -1.

As can be seen from Table 1, a great effect was observed in the lateral followability, which is the most important in the followability.

Next, looking at the internal curability, a silicone sealant for FIPG manufactured by Three Bond Co., Ltd. 1207B was applied as a room temperature-curable liquid rubber to the test flange having the cross-sectional shape shown in FIG. After standing, it was decomposed and checked for any uncured portions. Table 2 shows the results.

In Examples 1 and 2, since one side is largely open, the curing speed up to the inside is high.

Also, at this time, when the sealant was seen to protrude to the inner side, the sealant was pushed out to the opening side.

Next, regarding the degradability, a test piece having a cross-sectional shape shown in FIG. 5 and a length of 50 mm was pulled in a splitting direction at a pulling speed of 10 mm / min, and the decomposition strength was measured. At this time, Examples 1 and 2
The cutting was performed after making a notch as deep as possible with a cutter knife. The results are shown in Table-3.

As shown in Table-3, Examples 1 and 2 could be decomposed with a very small force. When this was assembled with an actual oil pan and tested, if the sealant in the conventional straight flange decomposed after being completely cured, the part would be greatly deformed when the screwdriver was inserted into a part and pryed apart. Was. On the other hand, when the seal surface of the stepped structure according to the present invention was cut open with a cutter after being cut with a cutter, it could be easily disassembled with a weak force and did not deform the oil pan.

In the present invention, the same effects as described above can be obtained even when the gap between the sealing surfaces is a tapered structure as shown in FIG.

Further, as shown in FIG. 4, if the notch 16 is slightly inserted into the metal touch portion on the seal inner side 12, it is effective in preventing the protruding sealant from dropping off, so that a more preferable flange shape is obtained.

Next, in order to see the difference in oil resistance due to the clearance, the clearance was set to 0, 0.1, 0.2, 0.3, 0.4, 0.5 mm with a 25 × 25 mm overlap using a 25 × 100 × 5 mm aluminum test piece made of JISH4000. After applying FIPG sealant 1212 manufactured by Three Bond Co., Ltd., and completely curing, immersed in gear oil 75w-90 at 150 ° C for 7 days, a tensile test was performed at a tensile speed of 50 mm / min, and the shear adhesive strength was measured. And the discoloration zone length of the sealant layer were measured. The results are shown in Table-4.

Considering this result and the fact that the sealant actually discolored in the flat oil pan flange part that traveled 100,000 km or more in actual vehicle traveling was about 1 mm at the inner part in contact with the oil, the inner side was The metal touch is very effective in terms of long-term oil resistance, and a width of about 2 mm is sufficient.

Sealant (room temperature curable liquid rubber) used in the present invention
As it cures at room temperature and adheres well to the flange member,
Any liquid sealant that becomes a rubber elastic body can be used. For example, silicone, modified silicone, polysulfide, polyurethane, acrylic urethane, modified polysulfide and the like can be mentioned.

〔The invention's effect〕

According to the above-described seal structure of the present invention, the pressure resistance in the uncured state is obtained, the good followability to the movement in the lateral direction is obtained, and the influence of the deterioration of the sealant by the seal medium is very unlikely. In addition, the curability to the inside of the sealant is very fast, and the working of the flange is simple. Furthermore, it is difficult for the sealant to protrude into the inner part, usually adheres well to the flange surface, follows the elongation of the sealant layer well, and the seal reliability is high. it can. In addition, since there are few metal touch portions and a rubber floating structure, many effects such as reduction of noise and vibration transmission can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view of a combination of an engine block and an oil pan of an automobile, and FIGS. 2, 3, and 4 are cross-sectional views of typical specific examples of a seal structure according to the present invention. FIG. 5 is a sectional view of the seal structure used in various experiments of the present invention, and FIG.
FIG. 8, FIG. 9, FIG. 9, FIG. 10 and FIG. 11 are a cross-sectional view of a known seal structure and a cross-sectional view for explaining a state of use thereof. 101 …… Engine block, 102 …… Oil pan, 10a, 10
b: Seal surface, 11: Room temperature curable liquid rubber, 12: Seal inner side, 13: Outside, 14: Opening clearance, 16: Notch, a: Cut-off structure, b: Taper Construction.

Claims (3)

(57) [Claims] 1. A seal structure for sealing between seal surfaces by interposing a room-temperature-curable liquid rubber between mutually facing seal surfaces of an engine block and an oil pan of an automobile, wherein a seal inner side between the seal surfaces is connected to each other. The contact and the outside are the opening clearance, the width of the surfaces that contact each other on the seal inner side is 1 mm or more, the thickness of the opening clearance is in the range of 1 mm to 5 mm, and the width of the opening clearance is the width of the seal inner side. A seal structure characterized in that the width is larger than the width of the surfaces that contact each other. 2. The sealing structure according to claim 1, wherein at least one of said sealing surfaces has a stepped structure that opens outwardly, whereby an outside clearance between the sealing surfaces serves as an opening clearance. Seal structure. 3. The sealing structure according to claim 1, wherein a space between the sealing surfaces is tapered so as to open outward from a seal inner side, whereby an outside clearance between the sealing surfaces is an opening clearance. And seal structure.