JP2014005854A - Cylinder head gasket - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cylinder head gasket in which horizontal displacement between an opening-side end portion of a grommet and a gasket substrate is prevented, thereby preventing reduction of a sealing performance in that portion.SOLUTION: A cylinder head gasket 1 comprises a plurality of gasket substrates 11-13 which are laminated mutually, and in the gasket substrates, combustion chamber holes 11a-13a and bolt holes 11b-13b are formed, respectively. A grommet 14 is provided to cover inner edges of all the combustion chamber holes 11a-13a, and opening-side end portions 14a, 14b of the grommet 14 are fixed to the gasket substrates 12 and 13 in contact with the grommet. Thus, even when displacement in a horizontal direction occurs between a cylinder head and a cylinder block, since the opening-side end portions of the grommet are fixed to the gasket substrates, horizontal displacement therebetween can be prevented, thereby maintaining an excellent sealing performance for a long time.

Description

  The present invention relates to a cylinder head gasket, and more particularly to a cylinder head gasket having a grommet.

2. Description of the Related Art Conventionally, a cylinder head gasket is known in which a plurality of gasket substrates having combustion chamber holes and bolt holes are stacked, and a grommet that covers the inner periphery of all combustion chamber holes is provided (Patent Document 1). ).
For example, the grommet is integrally connected to the outermost first gasket substrate among the plurality of stacked gasket substrates, and the grommet connected to the first gasket substrate is on the opposite side. The second gasket substrate is folded to the outermost side of the second gasket substrate and is superposed on the second gasket substrate.
In general, at least one of the contact surfaces of the gasket substrates that are in contact with each other is provided with a coating layer such as rubber in order to improve the sealing performance.

JP-A-64-80757

Conventionally, the above-described grommet has only been polymerized on the second gasket substrate. As a result, if a lateral displacement occurs between the cylinder head and the cylinder block due to the explosion pressure of the engine or the difference in thermal expansion between cold and operation, the lateral displacement may occur between the gasket substrates stacked in the multiple layers. Thus, a lateral shift occurs between the opening side end of the grommet and the second gasket substrate.
Then, due to the lateral displacement, the sealing performance between the grommet and the second gasket substrate is lowered, and particularly when a coating layer such as rubber is provided, the coating layer is easily damaged, so that the sealing performance is deteriorated. Became prominent.
In view of such circumstances, the present invention provides a cylinder head gasket capable of preventing lateral displacement between the opening side end portion of the grommet and the gasket substrate and preventing the sealing performance of the portion from being deteriorated. Is.

That is, the present invention is a cylinder head gasket in which a plurality of gasket substrates having combustion chamber holes and bolt holes are laminated, and a grommet that covers the inner peripheral edge of all the combustion chamber holes is provided.
The opening side end of the grommet is fixed to a gasket substrate in contact with the grommet.

  In the present invention, the opening side end of the grommet is fixed to the gasket substrate in contact with the grommet. Therefore, even if a lateral shift occurs between the cylinder head and the cylinder block, the opening side end of the grommet It is possible to prevent lateral displacement between the portion and the gasket substrate, and thus it is possible to maintain good sealing performance for a long time.

The top view of the principal part which shows 1st Example of this invention Expanded sectional view taken along line II-II in FIG. Sectional drawing which shows 2nd Example of this invention

Hereinafter, the present invention will be described with reference to the illustrated embodiment. In FIG. 1, a cylinder head gasket 1 according to the present embodiment is sandwiched between a cylinder head and a cylinder block (not illustrated) to seal between them. .
The cylinder head gasket 1 includes, for example, a plurality of combustion chamber holes 2 (only one is shown in FIG. 1) arranged in series on a straight line. Each of the plurality of combustion chamber holes 2 is a cylinder block (not shown). It is drilled in accordance with the position of the cylinder bore formed in.
Further, the cylinder head gasket 1 has a plurality of bolt holes 3 through which fastening bolts are inserted, a blow-by hole 4 through which blow-by gas flows, an oil hole 5 through which lubricating oil flows, and a water hole through which cooling water flows. 6 is drilled.

As shown in FIG. 2, the cylinder head gasket 1 is formed by laminating three gasket substrates 11, 12, and 13, and the gasket substrates 11 to 13 are formed in substantially the same shape.
Each of the gasket substrates 11 to 13 is provided with combustion chamber holes 11a to 13a and bolt holes 11a to 13a constituting the bolt holes 3 at the same position, and all of the combustion chamber holes 11a to 13a are included. The peripheral edge is covered with a grommet 14 having a C-shaped cross section provided separately from the gasket substrate. Thereby, the inner peripheral surface of the grommet 14 is formed as the combustion chamber hole 2.

The grommet 14 having a C-shaped cross section includes two opening end portions 14a and 14b on the upper and lower sides. The upper opening end portion 14a is in contact with and fixed to the upper surface of the upper gasket substrate 12. The opening end 14b is fixed in contact with the lower surface of the gasket substrate 13 below.
Adhesives or welding can be used as means for fixing the grommet 14 to the gasket substrates 12 and 13, and in particular, the opening side end portions 14a and 14b of the grommet 14 are fixed to the gasket substrates 12 and 13 in an endless manner by laser welding. It is desirable to improve the sealing performance of the portion.

  The upper gasket substrate 12 and the lower gasket substrate 13 are formed with full bead portions 12c and 13c surrounding the combustion chamber holes 2, respectively. The upper and lower full bead portions 12c and 13c are formed at the same position so as to overlap each other, and the full bead portion 12c formed on the upper gasket substrate 12 is formed so as to protrude upward toward the cylinder head, The full bead portion 13c formed on the lower gasket substrate 13 is formed so as to protrude downward toward the cylinder block.

By the way, when the cylinder head gasket 1 is sandwiched between the cylinder head and the cylinder block and the cylinder head and the cylinder block are connected with a fastening bolt, the surface pressure around the combustion chamber hole 2 is changed to a position near the bolt hole 3. Large at A and small at the separation position B separated from the bolt hole 3.
Accordingly, the intermediate gasket substrate 11 is provided with a concavo-convex portion 11c so as to endlessly surround the combustion chamber hole 11a within the range in which the upper and lower full bead portions 12c and 13c are formed. That is, as shown in FIG. 1, the concavo-convex portion 11c has a low height at a position A in the vicinity of the bolt hole 3 and a high height at a separation position B separated from the bolt hole 3. The interval is set to change smoothly and gradually.
Accordingly, the surface pressure around the combustion chamber hole 2 can thereby be made as uniform as possible.

In the above configuration, when the cylinder head gasket 1 is sandwiched between the cylinder head and the cylinder block and the cylinder head and the cylinder block are connected by the fastening bolt, the surface pressure around the combustion chamber hole 2 is increased by the bolt hole 3. Near the position A and small at the separation position B separated from the bolt hole 3.
However, the height of the concavo-convex portion 11c at the position A near the bolt hole 3 is low and the height of the concavo-convex portion 11c at the separation position B separated from the bolt hole 3 is high, so that the surface pressure around the combustion chamber hole 2 can be controlled. It can be made as uniform as possible. Accordingly, it is possible to prevent a decrease in the sealing performance at the portion where the surface pressure is low, and to secure a good sealing performance.
Even if the cylinder head and the cylinder block are laterally displaced due to the explosion pressure of the engine or the difference in thermal expansion between when the engine is cold and during operation, the upper gasket substrate 12 and the lower gasket substrate 13 have a cross section C. Since it is integrally fixed by the letter-shaped grommet 14, the lateral displacement between the gasket substrates 11 to 13 laminated in the plurality of layers is suppressed, and in particular, the opening side end portion 14 a of the grommet 14, The sealing performance between 14b and the gasket substrates 12 and 13 is maintained. Accordingly, it is possible to maintain good sealing performance for a long time.

FIG. 3 shows a second embodiment of the present invention. The grommet 24 in this embodiment is integrated with the gasket substrate 12 that is the outermost and uppermost of the three laminated gasket substrates 11 to 14. It is connected to. The grommet 24 integrally connected to the upper gasket substrate 12 is folded toward the gasket substrate 13 which is the outermost and lower side on the opposite side, and is superposed on the gasket substrate 13. The opening side end 24a of 24 is fixed to the gasket substrate 13 by the appropriate means described above.
In the present embodiment, a ring-shaped shim plate 25 surrounding the combustion chamber hole 11a is provided between the upper gasket substrate 12 and the intermediate gasket substrate 11. The shim plate 25 is provided over a range where the full beads 12c and 13c are superposed and over a range where the concave and convex portions 11c are formed.
Other configurations are the same as those of the first embodiment, and the same or corresponding parts as those of the first embodiment are denoted by the same reference numerals as those of the first embodiment.
In the second embodiment having the above-described configuration, it is obvious that the same effect as that of the first embodiment can be obtained. In this embodiment, the ring-shaped shim plate 25 is provided to provide the surface pressure at that portion. Therefore, it is possible to further improve the sealing performance.

DESCRIPTION OF SYMBOLS 1 Cylinder head gasket 2 Combustion chamber hole 3 Bolt hole 11, 12, 13 Gasket board | substrate 11a, 12a, 13a Combustion chamber hole 11b, 12b, 13b Water hole 11c Uneven part 12c, 13c Full bead part 14, 24 Grommet 14a, 14b, 24a Opening end 25 Shim plate A Neighborhood position B Separation position

Claims (6)

In a cylinder head gasket provided with a plurality of gasket substrates having combustion chamber holes and bolt holes, and provided with grommets covering the inner periphery of all combustion chamber holes,
A cylinder head gasket characterized in that an opening side end of the grommet is fixed to a gasket substrate in contact with the grommet.   The grommet is provided separately from the plurality of gasket substrates and is formed in a C-shaped cross section, and the two opening side ends of the grommet are respectively connected to the two gasket substrates in contact with the grommet. The cylinder head gasket according to claim 1, wherein the cylinder head gasket is fixed.   The grommet is integrally connected to the outermost first gasket substrate among the plurality of stacked gasket substrates, and the grommet connected to the first gasket substrate is the most on the opposite side. 2. The cylinder according to claim 1, wherein the cylinder is folded back to the outer side of the second gasket substrate and superposed on the second gasket substrate, and the opening end of the grommet is fixed to the second gasket substrate. Head gasket.   The cylinder head gasket according to any one of claims 1 to 3, wherein the grommet is fixed to the gasket substrate endlessly by laser welding.   Three gasket substrates are laminated, and a full bead portion is formed in each of the outermost first gasket substrate and the second gasket substrate so as to endlessly surround the combustion chamber holes, and the third gasket substrate at the center is 5. The thickness in the circumferential direction of the portion where each full bead portion is overlapped is set to be thin at a position near the bolt hole and thick at a position separated from the bolt hole. The cylinder head gasket according to any one of the above.   6. A ring-shaped shim plate surrounding a combustion chamber hole is provided between the gasket substrates, and the shim plate is provided over a range where the full beads are polymerized. Cylinder head gasket as described.

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