JP2009156061A - Cylinder head gasket - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cylinder head gasket capable of suppressing deformation of a cylinder while keeping sealing performance between a cylinder head and a cylinder block. <P>SOLUTION: The cylinder head gasket 40 is clipped and held between the cylinder block 20 having a water jacket 22 opened on an abutting surface to the cylinder head 30 to surround the cylinder 21 and the cylinder head 30. The cylinder head gasket 40 comprises a sealing part coated with sealing material for improving the sealing property to surround the cylinder and a friction part coated with friction material having a friction coefficient larger than that of the sealing material between the cylinder 21 and the water jacket 22 in an abutting surface of the gasket 40 to the cylinder block 20. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a cylinder head gasket that is sandwiched between a cylinder head and a cylinder block and seals between the members.

  A cylinder head gasket sandwiched between a cylinder head and a cylinder block of an internal combustion engine seals between these members and lubricates the combustion gas generated in the cylinder, and lubricates sliding parts such as pistons and valve valves. Prevents leakage of cooling water in the jacket.

  The cylinder head gasket is made of a single layer or a plurality of layers of a metal substrate, and a soft rubber such as fluorine rubber or nitrile rubber is applied to a contact surface with another member of the substrate. This soft rubber improves the sealing performance of the gasket by filling the fine irregularities generated on the contact surface of the other member with the gasket by processing or the like.

  By the way, the pressure in the cylinder rises due to the combustion of fuel accompanying the engine operation, and reaches the maximum pressure when the piston is near the compression top dead center. This pressure acts as a force for expanding the upper end portion of the cylinder, that is, a force for deforming the water jacket formed so as to surround the cylinder. Then, the soft rubber applied to the cylinder head gasket is deformed, the cylinder block and the gasket move relative to each other, and the friction coefficient of the rubber is low. The upper end portion is deformed to the water jacket side. As a result, an excessive stress is generated on the cylinder side of the peripheral wall of the water jacket, and this is repeated each time combustion is performed in the combustion chamber, so that a crack may occur with the inner wall as a base point. In particular, in a so-called open deck type cylinder block in which a water jacket opens on the contact surface with the cylinder head so as to surround the cylinder, such deformation of the cylinder tends to increase.

Therefore, in the invention described in Patent Document 1, a coating material obtained by kneading metal powder or talc having a high friction coefficient is applied to the entire contact surface of the cylinder head gasket made of a single layer metal substrate with the cylinder block. I am doing so. As a result, slippage of the cylinder block with respect to the gasket can be suppressed. Therefore, when a force for deforming the upper end of the cylinder toward the water jacket acts, the gasket also tries to move in the deformation direction. However, since the gasket is fastened to the cylinder head and the cylinder block with bolts, movement of the gasket is restricted. As a result, it is possible to receive a force for deforming the upper end portion of the cylinder by the gasket, and the deformation of the cylinder can be suppressed.
JP 2003-129903 A

  However, the coating material used in the invention described in Patent Document 1 has not only a high coefficient of friction but also a high hardness as compared with a conventionally applied soft rubber. Therefore, since the fine irregularities present on the contact surface of the cylinder block with the gasket cannot be sufficiently filled, the sealing performance between the cylinder block and the cylinder head gasket is deteriorated, and combustion gas and lubricating oil may leak. There is. In addition, there is a concern that the coating material may be damaged due to vibration along the direction of movement of the piston that occurs during engine operation due to a decrease in elasticity accompanying an increase in hardness.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a cylinder head gasket capable of suppressing the deformation of the cylinder while maintaining the performance of sealing between the cylinder head and the cylinder block. There is.

In the following, means for achieving the above object and its effects are described.
The invention according to claim 1 is a cylinder head gasket that is sandwiched between a cylinder block in which a water jacket surrounds the cylinder on a contact surface with the cylinder head and the cylinder head, and the cylinder head gasket A sealing portion in which a sealing material for improving the sealing performance is applied between the cylinder and the water jacket of the contact surface with the block so as to surround the cylinder, and has a higher coefficient of friction than the sealing material. The gist of the present invention is to include a friction part coated with a friction material.

  According to the above configuration, the cylinder head gasket is applied between the cylinder and the water jacket on the contact surface with the cylinder block so that the sealing material for improving the sealing performance surrounds the cylinder. Since the sealing portion is provided, the sealing performance of the gasket can be ensured by the sealing portion. In addition, as said sealing material, soft rubbers, such as a fluorine rubber and a nitrile rubber, are employable, for example.

  Further, the cylinder head gasket includes a friction portion in which a friction material having a friction coefficient larger than that of the sealing material is applied between the cylinder and the water jacket on a contact surface with the cylinder block. Yes. Therefore, the combustion of fuel during engine operation increases the internal pressure of the cylinder, particularly the internal pressure at the upper end of the cylinder, and suppresses slippage of the cylinder block against the cylinder head gasket that occurs when the cylinder block is deformed to the water jacket side. it can. In addition, the cylinder head gasket is fastened to the cylinder head and the cylinder block by bolts, and the surface pressure of the gasket is higher in the vicinity of the fastening portion than the other portions, and the cylinder block is less likely to slip with respect to the cylinder head gasket. As a result, the cylinder head gasket receives the force that deforms the cylinder upper end of the cylinder block toward the water jacket, so that deformation of the cylinder can be suppressed. In addition, as said friction material, resin, hard rubber, etc. are employable, for example.

  According to a second aspect of the present invention, in the first aspect of the present invention, the sealing material that improves the sealing performance in a portion corresponding to the space between the cylinder and the water jacket in the contact surface with the cylinder head. The gist includes a sealing portion applied so as to surround the cylinder, and a friction portion applied with a friction material having a friction coefficient larger than that of the sealing material.

  In many cases, the cylinder head gasket receives a force that deforms the cylinder toward the water jacket, thereby suppressing the deformation of the cylinder. However, depending on the rigidity and mass of the cylinder head gasket, the deformation of the cylinder may not be sufficiently suppressed.

In this regard, according to the second aspect of the present invention, the sealing material is formed on the portion of the contact surface of the cylinder head gasket with the cylinder head that corresponds to the space between the water jacket formed on the cylinder block and the cylinder. Is also provided with a friction portion coated with a friction material having a large friction coefficient. Therefore, the internal pressure at the upper end of the cylinder increases due to fuel combustion during engine operation, and the cylinder block slips when the cylinder block is deformed to the water jacket side, which can be received by the cylinder head via the gasket. it can. Similarly to the cylinder block, the cylinder head gasket and the cylinder head are fastened by bolts, and the surface pressure of the gasket is higher in the vicinity of the fastening portion than in other parts, so that the cylinder head slides against the cylinder head gasket. Is less likely to occur. As a result, the force that deforms the cylinder upper end portion of the cylinder block toward the water jacket is applied to the cylinder head gasket and the cylinder head, so that the deformation of the cylinder can be more reliably suppressed.

  In addition, the sealing performance between the cylinder head gasket and the cylinder head is such that the portion corresponding to the space between the water jacket formed on the cylinder block and the cylinder on the contact surface of the gasket with the cylinder head is sealed. An improved sealing material is maintained by a seal applied to surround the cylinder.

The gist of the invention described in claim 3 is that, in the invention described in claim 1 or 2, the sealing portion is provided on the protruding side surface of the bead portion from which the surface of the contact surface protrudes.
The bead portion, which is a portion where the surface of the contact surface with the other member of the cylinder head gasket protrudes, is a portion where the load due to bolt tightening is concentrated, and the internal pressure of the cylinder increases and the gap between the cylinder head and the cylinder block is increased. This is a part that follows the area when it expands. Therefore, as described in the third aspect of the invention, the sealing performance of the cylinder head gasket can be improved by providing the sealing portion on the protruding side surface of the bead portion.

  According to a fourth aspect of the present invention, in the cylinder head gasket according to any one of the first to third aspects, between the cylinder and the water jacket, the friction portion is formed on the whole except the sealing portion. The gist of this is

  According to the above configuration, the entire portion of the contact surface with the other member of the cylinder head gasket excluding the sealing portion is used as a friction portion. The frictional force generated between the contact surface of the member with the gasket can be maximized. Therefore, the deformation of the cylinder can be suppressed more reliably.

  According to a fifth aspect of the present invention, in the cylinder head gasket according to any one of the first to fourth aspects, a coefficient of friction is greater than that of the sealing material at a portion opposite to the cylinder across the water jacket. The gist is to have a friction part coated with a large friction material.

  According to the above configuration, since the frictional force on the opposite side of the cylinder across the water jacket is increased, a force for moving the gasket can be received by the same portion. Therefore, since the force acting on the gasket is received by the friction part and the vicinity of the portion fastened by the bolt, the deformation of the cylinder head can be further suppressed.

An embodiment of the present invention will be described below with reference to FIGS.
FIG. 1 shows a schematic structure of an internal combustion engine in which the cylinder head gasket according to the present embodiment is employed.

As shown in FIG. 1, the cylinder block 20 of the internal combustion engine 10 is provided with four cylinders 21, and a water jacket 22 that surrounds the cylinders 21 and opens in the same plane as the cylinders 21 is formed. Has been. In this opening surface, ten bolt holes 23 starting from the same surface are provided. Further, the cylinder head gasket 40 and the cylinder head 30 sandwiched between the cylinder block 20 and the cylinder head 30 have bolt holes 41 at positions corresponding to the bolt holes 23 of the cylinder block 20.
(The cylinder head is not shown).

  When the internal combustion engine 10 is assembled, the bolts (not shown) of the cylinder head 30, the bolt holes 41 of the cylinder head gasket 40 and the bolt holes 23 of the cylinder block 20 provided corresponding thereto are the same bolts (not shown). ) Is passed. And these members are fastened by fastening this bolt (not shown).

  When fuel is combusted as the internal combustion engine 10 is operated, the pressure in the cylinder rises, and when a piston (not shown) that moves up and down along the cylinder 21 is near the compression top dead center, in other words, When the upper end portion is in the vicinity of the upper end portion of the cylinder 21, the maximum pressure is obtained. This pressure acts as a force for expanding the upper end portion of the cylinder 21, that is, a force for deforming in the direction of the water jacket 22 formed so as to surround the cylinder 21. Even if this force is applied, in the vicinity of the bolt hole 41 of the cylinder head gasket 40, since the surface pressure is increased by tightening the bolt, the cylinder block 20 is not slipped with respect to the gasket 40, but close to the cylinder 21. Slip occurs in the portion, and the upper end portion of the cylinder 21 is deformed. In order to suppress this slip, a material having a large friction coefficient may be applied to the entire contact surface of the cylinder head gasket 40 with the cylinder block 20 to increase the frictional force generated between these members. However, in general, a material having a large friction coefficient has a high hardness, which causes a problem that the sealing performance of the gasket 40 is deteriorated.

  Therefore, in the present embodiment, a sealing material that improves the sealing performance surrounds the cylinder 21 between the cylinder 21 and the water jacket 22 in the contact surface of the cylinder head gasket 40 with the cylinder block 20. An applied sealing part and a friction part to which a friction material having a friction coefficient larger than that of the sealing material is applied are provided.

The detail of the cylinder head gasket in this embodiment is demonstrated with reference to FIG.2 and FIG.3.
FIG. 2 shows a partial cross-sectional structure of the cylinder head gasket and the cylinder block along the line AA in FIG.

  As shown in FIG. 2, the cylinder head gasket 40 is formed by laminating two bead plates 42 and 43 and an inner shim 44 sandwiched between them. The two bead plates 42 and 43 include a portion where the contact surface of the bead plate 42 that contacts the cylinder block 20 contacts between the cylinder 21 and the water jacket 22, and that of the bead plate 43 that contacts the cylinder head 30. First bead portions 42a and 43a projecting toward the respective abutting members are formed at corresponding portions. These first bead portions 42 a and 43 a are formed so as to surround the cylinder 21. Further, second bead portions 42b and 43b projecting toward the contact member side are also formed on the side opposite to the cylinder 21 with the water jacket 22 interposed therebetween. These second bead portions 42 b and 43 b are formed so as to surround the water jacket 22.

Next, FIG. 3 is an enlarged view in which the range B of the bead plate 42 in FIG. 2 is enlarged.
As shown in FIG. 3, the bead plate 42 includes a metal substrate 42 c as a main body, and protrudes toward the cylinder block 20 among the contact surface with the inner shim 44 and the contact surface with the cylinder block 20. The bead portion 42a is provided with a sealing portion 42d to which a sealing material having a high sealing property such as fluorine rubber or nitrile rubber is applied. In addition, a friction part in which a friction material having a higher friction coefficient than that of a sealing material such as resin or hard rubber is applied to a part other than the bead part 42a in the range B on the contact surface with the cylinder block 20. 42e is provided. A sealing material is applied to a portion other than the range B of the bead plate 42, and the other bead plate 43 is provided with a metal substrate as a main body like the bead plate 42, and the entire outer periphery thereof is provided. A sealing portion to which a sealing material is applied is provided.

  When the cylinder head gasket 40 is sandwiched between the cylinder block 20 and the cylinder head 30 by assembling the internal combustion engine 10, the sealing portion 42 d provided on the bead portion 42 a of the bead plate 42 is connected to the gasket 40 of the cylinder block 20. It enters into the fine irregularities formed by processing or the like on the contact surface. As a result, the sealing between the cylinder block 20 and the gasket 40 is improved by filling the unevenness.

  Further, when the upper end portion of the cylinder 21 (left blank paper portion in FIG. 2) is increased in pressure by combustion accompanying the operation of the internal combustion engine 10, the upper end portion tends to be deformed toward the water jacket 22 side. At this time, a large frictional force is generated at the contact surface between the friction portion 42e provided on the bead plate 42 on the cylinder block 20 side of the cylinder head gasket 40 and the bead plate 42 of the cylinder block 20, and the cylinder block 20 The cylinder head gasket 40 and the cylinder head gasket 40 are integrated to try to move to the opposite side of the cylinder 21 with the water jacket 22 interposed therebetween. However, in the part opposite to the cylinder 21, the surface pressure is higher than the part on the cylinder 21 side by tightening the bolts that fasten the cylinder head 30 and the cylinder block 20, and the movement of these members in the horizontal direction in FIG. Limited. Therefore, the cylinder head gasket 40 receives the force that deforms the upper end portion of the cylinder 21.

According to the embodiment described above, the following effects can be obtained.
(1) According to this embodiment, the cylinder head gasket 40 surrounds the cylinder 21 between the cylinder 21 and the water jacket 22 on the contact surface with the cylinder block 20 between the cylinder 21 and the water jacket 22. Since the sealing portion 42d applied in this manner is provided, the sealing performance of the gasket 40 can be secured by the sealing portion 42d. In addition, the gasket 40 includes a friction portion 42e between the cylinder 21 and the water jacket 22 on the contact surface with the cylinder block 20 and coated with a friction material having a friction coefficient larger than that of the sealing material. ing. Therefore, the combustion of fuel during engine operation increases the internal pressure of the cylinder 21, particularly the internal pressure at the upper end of the cylinder 21, and the cylinder block 20 is deformed toward the water jacket 22 side. Slip can be suppressed. In addition, the cylinder head gasket 40 is fastened to the cylinder head 30 and the cylinder block 20 with bolts, and the surface pressure of the gasket 40 is higher in the vicinity of the fastening portion than the other portions, and the cylinder head 20 is in contact with the cylinder head gasket 40. Slip is unlikely to occur. As a result, since the cylinder head gasket 40 receives the force that deforms the upper end portion of the cylinder 21 of the cylinder block 20 toward the water jacket 22, the deformation of the cylinder 21 can be suppressed.

  (2) The bead portion 42a, which is a portion projecting toward the cylinder block 20 on the contact surface of the cylinder head gasket 40 with the cylinder block 20, is a portion where the load due to bolt tightening is concentrated, and the cylinder internal pressure increases. When the gap between the cylinder head 30 and the cylinder block 20 is enlarged, it is a part that follows the gap. By providing the sealing portion 42d on the protruding side surface of the bead portion 42a, the sealing performance of the cylinder head gasket 40 can be improved.

  (3) Of the range B on the contact surface of the cylinder head gasket 40 with the cylinder block 20, the entire portion excluding the sealing portion 42d is the friction portion 42e, so that the sealing portion 42d ensures sealing performance, The frictional force generated between the cylinder head gasket 40 and the contact surface of the cylinder block 20 with the gasket 40 can be maximized. Therefore, the deformation of the cylinder 21 can be more reliably suppressed.

In addition, the said embodiment can also be implemented with the following forms which changed this suitably.
In the present embodiment, the friction plate 42e is provided at a portion other than the bead portion 42a between the cylinder 21 and the water jacket 22 on the contact surface of the bead plate 42 on the cylinder block 20 side with the cylinder block 20. It seems to be. That is, with reference to FIG. 4, among the contact surfaces of the bead plate 42 with the cylinder block 20, the range C on the cylinder 21 side and the range D on the water jacket 22 side across the bead portion 42 a. The friction part 42e is provided. Not only this but the friction part 42e may be provided in any one of the range C and the range D. In this case, the frictional force generated at the frictional part 42e and its contact surface is smaller than that in the present embodiment, but if it is possible to suppress the slipping of the cylinder block 20 by this frictional force, the above (1 ) And (2) can be obtained. In that case, a sealing portion may be provided on the other side of the range C and the range D.

  As in this embodiment, not only the friction part 42e is provided on the bead plate 42 on the cylinder block 20 side, but also the friction part may be provided on the bead plate 43 on the cylinder head 30 side. That is, in addition to the range C and the range D of the bead plate 42 in FIG. 4, a friction portion may be provided in at least one of the range E and the range F on the contact surface of the bead plate 43 with the cylinder head 30. When the friction part is also provided in the bead plate 43 on the cylinder head 30 side in this way, only the sliding of the cylinder block 20 with respect to the cylinder head gasket 40 that occurs when a force that deforms the upper end of the cylinder 21 toward the water jacket 22 is applied. In addition, the sliding of the cylinder head 30 with respect to the gasket 40 can be suppressed by the frictional force generated between these members. For this reason, the sliding of the cylinder block 20 with respect to the gasket 40 that occurs when the cylinder block 20 is deformed toward the water jacket 22 can be received by the cylinder head 30 via the gasket 40. Therefore, since the force applied to the upper end portion of the cylinder 21 is received by the cylinder head gasket 40 and the cylinder head 30, the effect (1) can be obtained more reliably. The bead portion 43 a of the bead plate 43 needs to be a sealing portion in order to ensure the sealing performance between the cylinder head 30 and the cylinder head gasket 40.

  Of the bead plate 42 on the cylinder block 20 side of the cylinder head gasket 40, the friction portion 42e is provided on the cylinder 21 side with respect to the water jacket 22 of the cylinder block 20 in contact with the bead plate 42, that is, in the range C and the range D in FIG. I have to. In addition to these, a friction portion may be provided on the side opposite to the cylinder 21 with the water jacket 22 interposed therebetween. In this case, in order to secure the sealing performance between the cylinder block 20 and the cylinder head gasket 40, it is necessary to provide a sealing portion in the second bead portion 42b. Can be provided. According to this configuration, the force acting on the upper end portion of the cylinder 21 is generated not only by the portion near the tightening of the bolt and having a higher surface pressure than the other portions, but also by the friction portion in the range G. Thus, the effect (1) can be obtained more reliably. Further, when the friction part is provided in the range H and the range F of the bead plate 43 on the cylinder head 30 side as described above, if the friction part is also provided in the range H corresponding to the range G, the upper end of the cylinder 21 is set. The part which receives the force which acts on a part can be increased further.

  -The part which provides the friction part 42e in the bead board 42 by the side of the cylinder block 20 may be made into any one of the range C and the range D, and the range G. In addition to this, the bead plate 43 on the cylinder head 30 side may be provided in either the range E or the range F and the range H. In the bead plates 42 and 43, the range of the portion where the sealing portion and the friction portion are provided can be changed as appropriate, and there may be a portion where the sealing portion and the friction portion are not provided.

-The shape of the cylinder head gasket 40 may not be restricted to this embodiment. For example, it is possible to provide a bead portion from the end portion of the bead plates 42 and 43 on the cylinder 21 side, or to have one bead portion per bead plate. Furthermore, it is not necessary to provide the bead portion, and the bead portion can be appropriately changed according to the size and output of the internal combustion engine to be applied.

  In the present embodiment, the cylinder head gasket 40 includes the two bead plates 42 and 43, but is not limited thereto, and may include one or two or more bead plates.

1 is a perspective view of an internal combustion engine in which an embodiment of the present invention is employed. The fragmentary sectional view which shows the same embodiment in the cross section along the AA line of FIG. 1, and the partial cross section structure of a cylinder block. The expanded sectional view which expanded the range B of FIG. The fragmentary sectional view which shows the other example in this invention, and the partial cross section structure of a cylinder block.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine, 20 ... Cylinder block, 21 ... Cylinder, 22 ... Water jacket, 23 ... Bolt hole, 30 ... Cylinder head, 40 ... Cylinder head gasket, 41 ... Bolt hole, 42, 43 ... Bead plate, 42a, 43a ... 1st bead part, 42b, 43b ... 2nd bead part, 42c ... Metal substrate, 42d ... Sealing part, 42e ... Friction part, 44 ... Inner shim.

Claims (5)

A cylinder block that is sandwiched between a cylinder block that opens so that a water jacket surrounds the cylinder on a contact surface with the cylinder head, and the cylinder head,
A sealing part in which a sealing material for improving sealing performance is applied between the cylinder and the water jacket in a contact surface with the cylinder block so as to surround the cylinder, and a coefficient of friction than the sealing material. A cylinder head gasket, comprising: a friction portion coated with a large friction material. The cylinder head gasket according to claim 1,
A sealing portion in which a sealing material for improving sealing performance is applied to a portion corresponding to a space between the cylinder and the water jacket in a contact surface with the cylinder head so as to surround the cylinder, and the sealing material And a friction part coated with a friction material having a friction coefficient larger than that of the cylinder head gasket. The cylinder head gasket according to claim 1 or 2,
The cylinder head gasket according to claim 1, wherein the sealing portion is provided on a protruding side surface of the bead portion from which the surface of the contact surface protrudes. In the cylinder head gasket according to any one of claims 1 to 3,
Between the cylinder and the water jacket, the friction part is formed on the whole except the sealing part. A cylinder head gasket. In the cylinder head gasket according to any one of claims 1 to 4,
A cylinder head gasket, comprising: a friction part to which a friction material having a friction coefficient larger than that of the sealing material is applied at a portion opposite to the cylinder across the water jacket.

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