JP7146260B2 - metal gasket - Google Patents

Description

TECHNICAL FIELD The present invention relates to a metal gasket mounted between a cylinder block and a cylinder head of an internal combustion engine (engine) to prevent leakage of combustion gas and liquids such as cooling water and lubricating oil, and more particularly, to a cylinder bore hole seal. and a half bead for cooling water hole and oil hole seals.

Metal gaskets are installed between the cylinder head and the cylinder block in internal combustion engines for automobiles, etc., to prevent leakage of high-pressure combustion gas from the cylinder bore holes, and prevent liquid holes such as cooling water holes and lubricating oil holes from leaking. It is designed to prevent leakage of liquids such as cooling water and lubricating oil (oil).

In recent years, as the output of internal combustion engines has increased, the combustion gas pressure has also increased, and various metal gaskets have been developed to cope with this. For example, Patent Document 1 discloses a metal gasket having one metal substrate having a full bead for sealing a cylinder bore hole and a half bead for sealing a liquid hole, and one sheet of step adjustment plate. A metal gasket is disclosed in which a step adjustment plate is fixed over a full bead so that the full bead side and the half bead side have different thicknesses. According to this metal gasket, when the metal gasket is installed between the cylinder block and the cylinder head and the cylinder head is tightened with the tightening bolt, the tightening force is greater on the full bead side where the step adjustment plate is superimposed than on the half bead side. Since force can be applied, the surface pressure of the full bead can be significantly higher than the surface pressure of the half bead, promoting compression of the full bead and improving sealing performance against leakage of combustion gas.

JP 2014-119075 A

By the way, when the step adjusting plate is used only on the full bead side to stabilize the sealing performance of the combustion gas, the compression on the half bead side tends to weaken. In particular, unlike the half bead for the water hole located inside the cylinder head bolt, the half bead for the oil hole located outside the cylinder head bolt tends to deteriorate the sealing performance.

Here, in the metal gasket described in Patent Document 1, the shape of the oil hole is circular or oval, and the half beads surrounding the oil hole are arranged substantially evenly along the inner edge of the oil hole. As a result, the half bead that surrounds the oil hole has a good sealing surface pressure, and it is rare that an imbalance in the surface pressure that leads to instability in sealing performance occurs. anxiety was relatively low.

However, if the shape of the plurality of oil holes formed in the metal gasket is not circular or oval but relatively complicated, the compression of the half bead during tightening will become unbalanced, resulting in a poor seal. There is a risk that the surface pressure will become unbalanced and the oil seal will become inadequate.

The present invention has been made in view of such problems, and its object is to provide a relatively complicated seal line for a half bead for an engine oil seal of an internal combustion engine, and furthermore, a portion of the surface far from the tightening bolt hole. To provide a metal gasket capable of sufficiently exhibiting an oil sealing function by averaging the surface pressure generated in a half bead even if the pressure is in an unbalanced state.

The metal gasket of the present invention is a metal gasket that is used by being mounted between a cylinder head and a cylinder block, and includes a single metal substrate,
a half bead forming an annular seal line surrounding both the oil hole on the joint surface of the cylinder head and the oil hole on the joint surface of the cylinder block, each having a different shape; an oil communication hole communicating with an oil hole of a cylinder block; and a bridge portion provided inside the half bead so as to divide the oil communication hole into a plurality of parts,
The bridge portion is provided with a surface pressure adjusting bead that abuts on the joint surface of the cylinder head or the joint surface of the cylinder block.

In the metal gasket of the present invention, it is preferable that the surface pressure adjusting bead abut against the joint surface of the cylinder head.

In the metal gasket of the present invention, the surface pressure adjusting bead preferably protrudes in a direction opposite to the protruding direction of the half bead.

According to the present invention, even if the seal line of the half bead for the engine oil seal of the internal combustion engine is relatively complicated, and furthermore, even if the surface pressure is partially unbalanced far from the tightening bolt hole, the surface where the half bead occurs It is possible to provide a metal gasket capable of averaging pressure and sufficiently exhibiting an oil sealing function.

1 is a plan view showing a metal gasket that is one embodiment of the present invention; FIG. 2 is a cross-sectional view taken along line D1-D1 of FIG. 1; FIG. FIG. 2 is an enlarged view of the D2 portion of the metal gasket shown in FIG. 1; 4 is a cross-sectional view taken along line E1-E1 of FIG. 3; FIG. FIG. 4 is a cross-sectional view taken along line E2-E2 of FIG. 3; 5 is a partially enlarged view of a cross section of the metal gasket shown in FIG. 4; FIG. FIG. 4 is a partially enlarged view of a metal gasket as a reference example; FIG. 4 is a cross-sectional view taken along line E1-E1 of FIG. 3, showing a state in which it is attached between the cylinder head and the cylinder block; FIG. 2 is a plan view of a metal substrate used for the samples of Examples and Comparative Examples; FIG. 10 is a graph of seal limit value confirmation results of Example J and Comparative Example C samples. FIG.

Hereinafter, the present invention will be described more specifically by way of example with reference to the drawings. FIG. 1 is a plan view showing a metal gasket G as one embodiment of the present invention.

The metal gasket G includes a metal substrate G1 made of a single metal plate, and as shown in FIG. and to prevent leakage of liquids such as cooling water and lubricating oil (oil). The metal gasket G of this embodiment particularly relates to the improvement of the half bead for oil hole seal, and aims to improve the surface pressure imbalance generated by the half bead.

The metal substrate G1 has a plurality of cylinder bore holes 1 and a full bead 8 for combustion gas sealing surrounding each of the cylinder bore holes 1 . In addition, the metal substrate G1 surrounds the plurality of cooling water holes 2 provided in the cylinder head 32 and the water jacket (WJ) provided in the cylinder block 31 so as to match the cooling water holes 2. A half bead 9 for sealing the cooling water hole 2, a half bead 10 for sealing a plurality of oil holes 3, and a half bead for sealing the chamber hole 4, which is a camshaft drive chain passage hole. 11.

Here, the oil communication hole 6 having a relatively complicated shape related to the present invention is arranged at the D2 portion shown in FIG. 1 of the plan view of the present application. In addition, the sealing half bead 12 is composed of a single annular continuous line in such a manner as to enclose and simultaneously surround the plurality of oil communication holes 6 divided (formed by the bridge portion 7) and the bridge portion 7. be. Further, as shown in FIG. 4, the bridge portion 7 is processed with a surface pressure adjusting bead 13 so that the projecting direction of the half bead 12 is opposite to that of the half bead 12 .

After applying the step adjustment plate 14 made of a metal plate thinner than the metal substrate G1 to the combustion gas sealing full bead 8 to the metal substrate G1 configured as described above, both metal substrates are crimped by a press caulking method called lance lock. It is a gasket in which plates (G1, 14) are integrated with a plurality of fixing parts 15 inside a water jacket.

FIG. 2 is a cross-sectional view taken along the arrow line D1-D1 in FIG. 14 and the fixed part 15 are shown.

Here, for comparison, the design of the oil hole seal portion will be described as a reference example. If the oil holes 72 and 73 on the joint surface of the cylinder head 32 of the internal combustion engine (engine) and the oil hole 71 on the joint surface of the cylinder block 31 are not of the same shape and position, both oil holes (72 and 73 and 71) at the same time, it is necessary to set the bead with one seal line surrounding both holes (72, 73 and 71) at the same time. FIG. 7 shows a configuration as a reference example of the portion corresponding to the portion D2 in FIG. 1, showing a configuration in which the bridge portion 7 and the surface pressure adjusting bead 13 are not processed over the entire oil hole.

In the metal gasket 100 shown in FIG. 7, two oil holes 72 and 73 (solid line) set in the joint surface (deck surface) of the cylinder head 32 and an oil hole 71 set in the joint surface of the cylinder block 31 ( dashed lines) are significantly different in shape. In such a case, the oil hole 74 provided in the metal substrate G1 is normally set so as to enclose both the oil holes 71, 72 and 73 at the same time. As a result, the half bead 12 is composed of one continuous line along the outer edge of the oil hole 74, and the seal line of the half bead 12 processed on the metal substrate G1 draws a relatively complicated seal line. Unlike the portion located near the tightening bolt hole 5, it is difficult for the bolt axial force to be transmitted to the portion far from the tightening bolt. . The cross-sectional view taken along the cross-sectional line E3-E3 in FIG. 7 has the same shape as the cross-sectional view of FIG. In addition, FIG. 5 shows the unprocessed portions of the bridge portion 7 and the surface pressure adjusting bead 13 .

Since it is difficult to further improve the tightening performance of the half bead 12 under the structure described above, it has been desired to improve the sealing surface pressure of the half bead 12 under the current tightening performance. Therefore, the inventor examined the surface pressure generated by the half bead 12 in the structure of the present application, and examined whether it is possible to adopt the surface pressure adjustment only in the portion far from the tightening bolt hole 5 and where the generated surface pressure is low.

Therefore, the inventor confirmed the state of both the joint surfaces of the cylinder head 32 and the cylinder block 31 in the embodiment of FIG. 72 and 73, but there is a flat portion 75 which is not machined as an oil hole on the joint surface of the cylinder head 32 located between both openings of the oil holes 72 and 73 of the cylinder head 32. I found out.

Therefore, the inventors proposed that the flat portion 75 existing in the cylinder head 32 be formed into a bead having a chevron-shaped cross section as shown in FIGS. I decided to apply bead processing so that it is positioned. Then, if this bead is set for adjusting the surface pressure, it may be possible to generate a strong surface pressure even in a portion far from the tightening bolt. A bridge portion 7 was set at G1, and a half bead was formed in the bridge portion 7 so as to be opposite to the projecting direction of the half bead 12, thereby forming a surface pressure adjusting bead 13.

FIG. 3 is a plan view showing this situation, showing the relationship between the bridge portion 7 provided on the metal substrate G1 and the surface pressure adjustment bead 13. FIG. The drawing shows the cross-sectional shapes of the bridge portion 7 and the surface pressure adjusting bead 13 , and also shows the relationship between the surface pressure adjusting bead 13 and the half bead 12 processed in the bridge portion 7 .

The details of the cross-sectional shape formed by the surface pressure adjusting bead 13 provided in the bridge portion 7 and the half bead 12 adjacent thereto are shown in FIG. and the oblique side of the surface pressure adjustment bead 13 are processed to be opposite to each other. FIG. 6 shows the height 12h (protrusion height) of the half bead 12 obtained from points P1, P2, and P3 formed by the tangent lines of the inclined portions and flat portions of the surface pressure adjusting bead 13 and the half bead 12, and the surface pressure adjusting bead. 13, the width 12w of the half bead 12 and the width 13w of the surface pressure adjusting bead 13 are shown.

Here, the horizontal line that forms the flat portion of the half bead 12 is S1, the oblique line that drops in the direction of the base is S2, the oblique projection line of the surface pressure adjustment bead 13 is line S3, and the horizontal line of the surface pressure adjustment bead 13. is the line S4, the intersections of the lines S1 to S4 are P1, P2, and P3, respectively, and the width 12w and the height 12h of the half bead 12 are composed of the horizontal distance and the vertical distance between the intersections P1 and P2. . The width 13w and height 13h of the surface pressure adjusting bead 13 are defined by the horizontal distance and vertical distance between the intersection points P2 and P3.

8 is a cross-sectional view of FIG. 4 with the cylinder head 32, the cylinder block 31, the oil hole 71 of the cylinder block 31, and the flat portion 75 of the cylinder head 32 added. A substrate corresponding to a flat portion 75 sandwiched between 72 and 73 is provided with a bridge portion 7, and the bridge portion 7 is provided with a surface pressure adjusting bead 13. The surface pressure adjusting bead 13 is located on the cylinder head. It touches only 32 flats 75 . Reference numeral 76 denotes a flat portion of the joint surface of the cylinder block 31. As shown in FIG. From the viewpoint of smooth movement of oil between the cylinder head 32 and the cylinder block 31 , the bridge portion 7 is preferably provided at a position that does not overlap the oil holes 72 and 73 of the cylinder head 32 .

Here, the operation of this embodiment is that when the metal gasket G is sandwiched between the cylinder head 32 and the cylinder block 31 and compressed by the tightening bolt, the cylinder head 32 is positioned at the apex P3 of the surface pressure adjusting bead 13. , the surface pressure adjusting bead 13 is compressed together with the half bead 12 . Therefore, the restoring force of the surface pressure adjusting bead 13 acts in the direction of compressing the half bead 12 for the oil hole, and the apexes P1 and P2 of the half bead 12, together with their own restoring force, reliably generate surface pressure. Become.

Such a structure is effective by appropriately providing the bridge portion 7 in the portion where the tightening axial force of the bolt is difficult to transmit, and processing the surface pressure adjustment bead 13 there. The half bead is a portion where the surface pressure was initially good even if the bridge portion 7 did not exist. is not required.

As described above, the metal gasket G of the present embodiment is used by being mounted between the cylinder head 32 and the cylinder block 31. The metal gasket G includes one metal substrate G1, and the cylinders having different shapes are used. A half bead 12 forming an annular seal line surrounding both the oil holes 72, 73 on the joint surface of the head 32 and the oil hole 71 on the joint surface of the cylinder block 31, and the oil hole 72 of the cylinder head 32 inside the half bead 12. , 73 and the oil hole 71 of the cylinder block 31, and a bridge portion 7 provided inside the half bead 12 so as to divide the oil communication hole 6 into a plurality of parts. , a surface pressure adjusting bead 13 that contacts the joint surface of the cylinder head 32 is provided.

As described above, the oil holes 72 and 73 on the joint surface of the cylinder head 32 and the oil hole 71 on the joint surface of the cylinder block 31, which have different shapes, must be simultaneously surrounded by one bead seal line. If not, it is difficult for the axial force of the tightening bolt to be transmitted to the portion far from the tightening bolt hole 5, and the seal surface pressure tends to be unbalanced. For example, even if there is no flat portion near the oil hole on the joint surface of the cylinder block 31, if the flat portion 75 exists near the oil hole on the joint surface of the cylinder head 32, the oil communication hole set in the metal gasket G The bridge portion 7 is provided so as to be located in a part of the flat portion 75 so as to divide the flat portion 75, and the surface pressure adjustment bead 13 is provided on the bridge portion 7, thereby eliminating the surface pressure imbalance. and excellent sealing performance around the oil communication hole 6 can be exhibited. That is, according to the present invention, even if the seal line of the half bead 12 for the engine oil seal of the internal combustion engine is relatively complicated, and furthermore, even if the surface pressure is unbalanced in a portion far from the tightening bolt hole 5, It is possible to provide a metal gasket G that can sufficiently exhibit an oil sealing function by averaging the surface pressure generated by the half beads 12 .

In addition, in the metal gasket G of this embodiment, since the surface pressure adjusting bead 13 is configured to abut on the joint surface of the cylinder head 32, compared to the case of abutting on the joint surface of the cylinder block 31, The sealing performance can be enhanced more effectively.

In addition, in the metal gasket G of this embodiment, the surface pressure adjustment bead 13 is provided so as to protrude in the direction opposite to the direction in which the half bead 12 protrudes. It can improve performance.

Further, in the metal gasket G of this embodiment, the height 12h of the half bead 12 is preferably 0.3 mm or more and 0.61 mm or less. An improvement effect can be exhibited.

Moreover, in the metal gasket G of this embodiment, the width 12w of the half bead 12 is preferably 1.5 mm or more and 2.5 mm or less. According to this, the rigidity of the half bead 12 and the restoring force of the half bead 12 can be properly balanced, and the effect of improving the sealing performance can be exhibited more reliably.

In order to confirm the above effects, the inventor prepared several types of Example J sample having the surface pressure adjusting bead 13 and Comparative Example C sample not having the surface pressure adjusting bead 13 and conducted an effect confirmation test.

The inventors manufactured the metal gaskets of the present application as samples of Examples and Comparative Examples and conducted an effect confirmation test. Samples for Example J and Comparative Example C were made. A plan view of a sample metal substrate 91 for each of Example J and Comparative Example C is shown in FIG. In preparing the Example J sample and the Comparative Example C sample using the metal substrates for both samples, the metal substrates for both samples were stainless steel plates (SUS301H- CSP) was coated on both sides with nitrilo rubber (NBR) having a film thickness of 0.025 mm on one side as a soft sealing material.

The details of the bead shape molded into both samples are the same as shown in FIG. In the above relationship, the half bead 12 and the bridge portion 7 were subjected to bead processing of the surface pressure adjusting bead 13, and J1 to J8 were used for the example samples. Comparative samples C1 to C6 were samples in which only the half bead 12 was processed.

Here, the inventor set the width 13w and the height 13h of the surface pressure adjusting bead 13 so that the shape dimensions of the width 13w and the height 13h are substantially constant when manufacturing the example sample, and Examples J1 to J8 were produced. The details of the manufactured examples J1 to J8 are shown in Table 1. The width 13w is constant at a nominal value of 3.2 mm in the range of 3.15 mm to 3.26 mm, and the height 13h is 0.62 mm to 0.62 mm. The width 12w of the half bead 12 is constant at a nominal value of 0.65 mm in the range of 0.67 mm, the width 12w of the half bead 12 is constant at a nominal value of 1.8 mm in the range of 1.82 mm to 1.95 mm, and the height 12h of the half bead 12 is 0. J1 to J8 were manufactured in the range of 0.20 mm to 0.73 mm.

Here, the inventor decided to manufacture a comparative example in order to investigate the effectiveness of the surface pressure adjusting bead 13, and did not form the surface pressure adjusting bead 13 on the bridge portion 7 of the metal substrate G1 cut by laser. Comparative Examples C1 to C6 were produced by forming only the half bead 12 on the . The details of the manufactured examples C1 to C6 are as shown in Table 1. The width 12w is constant at a nominal value of 1.8 mm in the range of 1.78 mm to 1.82 mm, and the height 12h is 0.21 mm to 1.82 mm. C1 to C6 were produced in the range of 0.71 mm.

The inventor confirmed the performance of Examples J1 to J8 and Comparative Examples C1 to C6 using the following "seal limit value performance" test.

"Seal limit value performance" test Then, while forcibly reducing the clamping load between both jigs, the distance between both jigs and the example and comparative example was increased.

It is possible to evaluate the sealing performance of the half bead by grasping the amount of opening phenomenon from the initial compression, that is, the relationship between the amount of opening (μm) and the presence or absence of leakage (loss) of lubricating oil. This is because I assumed that Specifically, the metal gasket was installed in an actual engine, and the compressive load applied to the half bead was investigated when the cylinder head was tightened to the cylinder block by bolts. The compression upper limit load of the universal testing machine used in the apparatus is set to the above value, and the comparative example sample is sandwiched between the upper jig and the lower jig and compressed. Then, when the pressing load of the universal testing machine reaches the upper limit compressive load, the output values of the two left and right gap sensors are set to zero. Next, the hydraulic pressure of the hydraulic pressure generator is set to the specified pressure (0.1 MPa), and the inside (oil reservoir) of the comparative sample is filled with oil of the oil type (10W-30) pressurized to the specified pressure, The pressing load of the universal testing machine is gradually reduced from the upper limit compression load. When the pressing load of the universal testing machine is gradually reduced,
When the upper jig rises and the surface pressure of the half bead decreases, and the pressing load of the universal testing machine decreases to a certain value, a gap is created between the comparative example sample and the lower jig, and the lubricating oil leaks inside the half bead. flows out from The gap (μm) between the comparative example sample and the lower jig was read from the output value of the gap sensor when the lubricating oil flowed out, and the value was defined as the "seal limit value".

The graph shown in FIG. 10 and Table 1 above are the results of seal limit performance tests of Example J and Comparative Example C. FIG.

In Comparative Example C (with no surface pressure adjusting bead), which has a conventional structure, the seal limit value gradually increases until the height 12h of the half bead 12 is 0.21 mm, 0.29 mm, 0.39 mm, and 0.5 mm. , 0.5 mm (Comparative Example C4) is the limit, and in this test, when 12w of the half bead 12 is set to about 1.8 mm, the bead height 12h with the best sealing performance is that of Comparative Example C4 (12h is 0 0.5 mm) is the limit, and it was found that a higher sealing performance could not be expected.

On the other hand, Example J in which the surface pressure adjusting bead 13 is combined with the half bead 12 (with the surface pressure adjusting bead) has better sealing performance than Comparative Example C, and in particular, the height 12h of the half bead 12 is 0.3 mm ( It was found that, in the case of Example J2) or above, a sealing property equal to or higher than that of Comparative Example C4 can be obtained.

In this test, when 13w of the surface pressure adjusting bead 13 was set to be approximately 3.2 mm, 13w was effective up to 0.6 mm (Example J6), and the degree of effectiveness was 1.0 mm compared to Comparative Example C4. Since the seal performance is five times higher, the bridge portion 7 can be formed in the oil communication hole 6 even when the shape of the oil hole is relatively complicated and the surface pressure of the half bead 12 sealing it is unbalanced. It was found that by adding the surface pressure adjusting bead 13 to the bridge portion 7 in the direction opposite to the rising direction of the half bead 12, the sealing limit performance of the bead is greatly improved.

It goes without saying that the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention.

For example, in the above embodiment, the surface pressure adjusting bead 13 contacts the joint surface of the cylinder head 32 , but may contact the joint surface of the cylinder block 31 .
Further, the shape and number of the oil communication holes 6 are not limited to the illustrated example, and can be changed as appropriate.
In addition, the number and arrangement of cylinder bore holes, cooling water holes, oil holes, bolt holes, and chamber holes are not particularly limited, and can be appropriately changed according to the shape of the cylinder head and cylinder block that constitute the internal combustion engine. be. Also, the cross-sectional shape of the seal ring, the shape in plan view, and the like can be changed as appropriate.

G: Metal gasket G1: Metal substrate 1: Cylinder bore hole 2: Cooling water hole 3: Oil hole 4: Chamber hole 5: Tightening bolt hole 6: Oil communication hole 7: Bridge portion 8: Full bead 9: Half bead 10: Oil hole Sealing half bead 11: Chamber hole sealing half bead 12: Half bead 13: Surface pressure adjusting bead 31: Cylinder block 32: Cylinder head 71: Oil hole 72, 73: Oil hole 74: Oil hole 75: Flat portion 100: Metal gasket

Claims (3)

A metal gasket that is mounted between a cylinder head and a cylinder block and includes a single metal substrate,
a half bead forming an annular seal line surrounding both the oil hole on the joint surface of the cylinder head and the oil hole on the joint surface of the cylinder block, each having a different shape; an oil communication hole communicating with an oil hole of a cylinder block; and a bridge portion provided inside the half bead so as to divide the oil communication hole into a plurality of parts,
A metal gasket, wherein the bridge portion is provided with a surface pressure adjusting bead that abuts on the joint surface of the cylinder head or the joint surface of the cylinder block. 2. The metal gasket according to claim 1, wherein said surface pressure adjusting bead is configured to abut against a joint surface of said cylinder head. 3. The metal gasket according to claim 1, wherein said surface pressure adjusting bead protrudes in a direction opposite to a protruding direction of said half bead.

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