JPH11304001A - Seal structure of engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the seal structure of an engine, which prevents the extrusion of a gasket, and also is excellent in seal durability between a cylinder head and a cylinder block. SOLUTION: This seal structure of an engine comprises a cylinder head 3, a cylinder block 5 having a plurality of air cylinders 50 and a gasket 2 arranged between the cylinder head 3 and the cylinder block 5. The gasket 2 comprises a matrix 21 having a plurality of gasket holes 20 communicating the cylinder head 3 with the cylinder block 5 and a U-shaped cross sectional grommet 23 sealing the peripheries of the gasket holes 20. A projected part 53 projected on the periphery of the opening part 51 of the air cylinder 50 is arranged on at least one of the cylinder block 5 and the cylinder head 3. The inner circumferential surface 231 of the grommet 23 of the gasket 2 is oppositely arranged on the peripheral surface 539 of the projected part 53.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine seal structure comprising a cylinder head, a cylinder block, and a gasket disposed between the cylinder head and the cylinder block, and more particularly to an engine seal structure having a projection at an opening of a cylinder of a cylinder block. .

[0002]

2. Description of the Related Art Conventionally, the following seal structure is known as an engine seal structure. As shown in FIGS. 9 to 12, the seal structure 9 includes a cylinder head 3, a cylinder block 95 having a plurality of cylinders 950, and a gasket 2. The gasket 2 has a gasket hole 20.
, A grommet 23, and a wiring 22.

[0003] The grommet 23 has one end 2.
33, the cylinder head 3 and the wiring 22,
The other end 235 is held by the base material 21.
With the cylinder block 95 and the wiring 22,
It is held by the base material 21. The grommet 23 is slidably disposed with respect to the cylinder head 3 and the cylinder block 95.

The gasket hole 20 is provided via the grommet 23 in the cylinder head 3, the cylinder block 95, and the bore 7 closed by the piston 75 (see FIG. 2). The gasket 2 is fixed between the cylinder head 3 and the cylinder block 95 by a head bolt (see FIG. 2). The seal structure 9 seals between the cylinder head 3 and the cylinder block 95 by the axial force (fastening force) of the head bolt.

[0005]

However, the conventional sealing structure 9 has the following problems. That is, the gasket 2 is heated and cooled and expands and contracts during operation of the engine. In particular, the amount of deformation of the gasket 2 increases in the longitudinal direction. For example, the above gasket 2
When is thermally expanded, as shown in FIGS. 10 and 11, the position of the gasket hole 20 of the gasket 2 shifts and does not correspond to the position of the cylinder 950 of the cylinder block 95. Although not shown, the gasket 2
When the gasket contracts, a positional shift between the gasket hole 20 and the cylinder 950 similarly occurs.

As described above, when a part of the gasket 2 is projected into the bore 7 (hereinafter, “projection”) due to the deformation of the gasket 2, the upper part of the piston 75 is moved to one side of the gasket 2. There is a possibility that the grommet 23 of the gasket 2 may be damaged by contact with the gasket 2. Further, if the damage further progresses, it is conceivable that fragments of the grommet 23 fall into the bore 7 and damage the piston 75 and the cylinder block 95.

The grommet 23 of the gasket 2
Is slidably disposed with respect to the cylinder head 3 and the cylinder block 95. Therefore, during operation of the engine, if the cylinder head 3 and the cylinder block 95 are heated and cooled to expand and contract, and a shear force acts between the two, the grommet 23 may slide as follows.

For example, when the cylinder head 3 and the cylinder block 95 are cooled and contract, FIG.
As shown in the figure, the cylinder head 3 is relatively shifted to the left and the cylinder block 95 is relatively shifted to the right, and the gap between them may be narrow. In this case, the grommet 23 is dragged by the cylinder head 3 and the cylinder block 95 and deforms while being pulled toward the other end 235.

After the cooling, the cylinder head 3 and the cylinder block 95 are heated and thermally expanded, as shown in FIG.
And the cylinder block 95 moves in the opposite direction. At this time, since the gap between them is slightly widened, the grommet 23 is not drawn into the one end 233 side. Therefore, the grommet 23 remains in a deformed state. As a result, even when the grommet 23 is deformed, the grommet 23 projects into the bore 7, and “projection” occurs as described above. If the grommet 23 is significantly deformed, the grommet 23 may be damaged, resulting in poor sealing.

The present invention has been made in view of the above-mentioned conventional problems, and provides an engine seal structure which can prevent the gasket from protruding and has excellent seal durability between the cylinder head and the cylinder block. What you want to do.

[0011]

According to a first aspect of the present invention, there is provided an engine sealing structure comprising a cylinder head, a cylinder block having a plurality of cylinders, and a gasket disposed between the cylinder head and the cylinder block. A base material having a plurality of gasket holes communicating between the cylinder block and the cylinder block, a grommet having a U-shaped cross section sealing the periphery of the gasket holes, and at least one of the cylinder block and the cylinder head has A projection protruding from the periphery of the opening of the cylinder is provided,
An inner peripheral surface of the grommet of the gasket is disposed so as to face an outer peripheral surface of the projection.

It is most remarkable in the present invention that at least one of the cylinder block and the cylinder head is provided with the protrusion, and the outer peripheral surface of the protrusion and the inner peripheral surface of the grommet of the gasket are arranged to face each other. It is doing.

Next, the operation of the present invention will be described. In the engine seal structure of the present invention, the projection is located on the inner peripheral side of the grommet of the gasket. Further, the outer peripheral surface of the projection is opposed to the inner peripheral surface of the grommet of the gasket. For this reason, even when the gasket is cooled and heated to deform (expand or contract) during operation of the engine, the deformation of the gasket is suppressed because the inner peripheral surface of the grommet abuts on the outer peripheral surface of the projection.

Further, even if the cylinder head and the cylinder block are cooled and heated, and the grommet is deformed in a state where the grommet is pulled into one of the two ends,
Since the inner peripheral surface of the grommet abuts on the outer peripheral surface of the projection, deformation of the grommet is also suppressed. Therefore,
The seal structure prevents the gasket and the grommet from being deformed by the protrusion, and restricts the gasket from protruding inward from the protrusion.
"Protrusion" of the gasket can be prevented. Further, the durability of the seal between the cylinder head and the cylinder block can be improved.

The height of the projection is preferably 10% to 50% or less of the thickness of the gasket.
In this case, even when the cylinder head and the cylinder block are cooled and heated to expand and contract during the operation of the engine, and the gap between the cylinder head and the cylinder block is narrowed, for example, the protrusion provided on the cylinder block may be Contact with the cylinder head can be prevented. Further, the projection provided on the cylinder head can be prevented from contacting the cylinder block. If the height of the projection is less than 10% of the thickness of the gasket, the grommet of the gasket may get over the projection and protrude into the bore.

Next, as in the second aspect of the present invention, it is preferable that the protruding portion is disposed at an opening of a cylinder located at both ends of the plurality of cylinders. In this case, since the cylinders located at both ends correspond to the longitudinal direction of the gasket, the deformation amount of the gasket is particularly large (see FIGS. 10 and 11). Therefore, by providing the protrusions for preventing the gasket from being deformed at the opening portions of the cylinders at both ends, it is possible to more effectively prevent the "protrusion" of the gasket.

Next, as in the third aspect of the present invention, it is preferable that the protrusion is formed by a cylinder liner provided on the inner wall of the cylinder. In this case, the upper end of the cylinder liner can be used as the projection by arranging the upper end of the cylinder liner so as to protrude more toward the cylinder head than the upper end of the cylinder block. Therefore, the protrusion can be easily formed.

Next, it is preferable that the projecting portion is provided in a ring shape. In this case, "projection" of the gasket can be prevented more reliably. Further, the formation of the above-mentioned projection is easy.

Next, it is preferable that a plurality of the protrusions are provided at an interval.
In this case as well, it is possible to prevent the gasket from "protruding" in the same manner as described above.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 An engine seal structure according to an embodiment of the present invention will be described with reference to FIGS. As shown in FIGS. 1 to 5, the seal structure of the present embodiment includes a cylinder head 3, a cylinder block 5 having a plurality of cylinders 50, and a gasket 2 disposed therebetween. Gasket 2 above
A base material 21 having a plurality of gasket holes 20 (FIG. 5) for communicating between the cylinder head 3 and the cylinder block 5; a grommet 23 having a U-shaped cross section for sealing the periphery of the gasket holes 20; It comprises a wire ring 22 housed between the grommet 23 and the base material 21.

The cylinder block 5 is provided with a projection 53 protruding toward the cylinder head 3 at the periphery of the opening 51 of the cylinder 50, and the inner peripheral surface of the grommet 23 of the gasket 2. The reference numeral 231 is arranged to face the outer peripheral surface 539 of the projection 53.

Hereinafter, description will be made step by step. As shown in FIGS. 1 and 2, the seal structure 1 includes the cylinder block 5 and the cylinder head 3 mounted thereon.
The gasket 2 is interposed between them. The gasket 2 is a gasket for four cylinders as shown in FIG. 3, and the base material 21 of the gasket 2 has four gasket holes 20 (FIG. 5). The cylinder block 5 is a cylinder block for four cylinders, and has four cylinders 50 arranged in series.

As shown in FIG. 1, at the periphery of the four gasket holes 20, the base material 21 of the gasket 2 has a step for attaching both ends of the grommet 23. The grommet 23 of the gasket 2 is formed in an annular shape.
While holding the step of the grommet 23 from above and below,
The gasket hole 20 is provided on the periphery. Also,
The inner peripheral surface 231 of the grommet 23 indicates a bent portion of the grommet 23.

The base material 21 is made of a non-metal such as graphite, and the grommet 23 is made of a metal. Further, as shown in FIG.
Has a number of bolt holes 27 and a number of cooling water holes 28. In addition, in FIG. 2, the code | symbol 58 is a cooling water channel.

On the other hand, as shown in FIGS. 1 and 2, on the periphery of the opening 51 of the cylinder 50, the cylinder block 5 has a projection 53 projecting toward the cylinder head 3. The protrusion 53 has a substantially square cross-sectional shape, and the height h is 50% of the thickness t of the gasket 2. The inner peripheral surface 231 of the grommet 23 of the gasket 2 is disposed to face the outer peripheral surface 539 of the projection 53. The protrusion 53
The outer diameter of the outer peripheral surface 539 is substantially equal to the inner diameter of the inner peripheral surface 231 of the grommet 23.

Further, as shown in FIG.
Are arranged in the openings 51 of the cylinders 50 located at both ends of the four cylinders 50 in the cylinder block 5. As shown in FIG. 4, the projection 53 is an annular projection provided on the entire circumference of the opening 51 of the cylinder block 5.

As shown in FIG. 2, the gasket 2 is provided with a plurality of bolt holes 27 (FIG. 5) through which head bolts 4 for fastening are inserted and screwed into the cylinder head 3 and the cylinder head 3. It is assembled and fixed between the block 5. Thereby, the cylinder block 5
Of the cylinder 50, the gasket 2,
And is closed by the piston 75 to form a bore 7 as a combustion chamber.

The seal structure 1 generates a surface pressure between the cylinder head 3 and the upper end of the grommet 23 by the axial force (fastening force) of the head bolt 4 (FIG. 2), and generates the grommet. By generating a surface pressure between the lower end of the cylinder block 23 and the cylinder block 5, the space between the cylinder head 3 and the cylinder block 5 is sealed.

Next, the operation of the present embodiment will be described. In the engine seal structure 1 of the present embodiment, as shown in FIGS. 1 and 2, the projection 53 is located closer to the bore 7 (inner circumference) than the grommet 23 of the gasket 2. Further, the outer peripheral surface 539 of the projection 53 is provided with the gasket 2.
And the inner peripheral surface 231 of the grommet 23. Therefore, even when the gasket 2 is cooled and heated to deform (expand or contract) during operation of the engine (not shown), the inner peripheral surface 231 of the grommet 2 comes into contact with the outer peripheral surface 539 of the projection 53. The deformation of the gasket 2 is suppressed.

Further, even if the cylinder head 3 and the cylinder block 5 are cooled and heated to deform the grommet 23 in a state in which the grommet 23 is pulled into one of the two ends, the outer peripheral surface 539 of the projection 53 is formed. Since the inner peripheral surface 231 of the grommet 23 contacts, deformation of the grommet 23 is also suppressed. Therefore, the above-mentioned sealing structure 1
The protrusion 53 prevents the gasket 2 and the grommet 23 from being deformed and restricts the grommet 23 of the gasket 2 from projecting toward the bore 7 beyond the protrusion 53. Protruding "
Can be prevented.

Further, as shown in FIG.
Are arranged in the cylinders 50 at both ends of the four cylinders 50, which correspond to the longitudinal direction of the gasket 2 and in which the deformation of the gasket 2 is particularly large. Therefore, by providing the projections 53 for preventing the deformation of the gasket 2 at the openings 51 of the cylinders 50 at both ends, it is possible to more effectively prevent the gasket 2 from protruding. Also, the openings 51 of the two cylinders 50 located inside
Since the projection 53 need not be provided, the seal structure 1 can be made simpler.

Further, as shown in FIG.
Is annular, the gasket 2 cannot project into the bore 7 from any direction. Therefore, it is possible to more reliably prevent the "protruding" of the gasket 2. Further, the formation of the projection 53 is easy.

Further, since the deformation of the grommet 23 is suppressed, it is possible to prevent the grommet 23 from being damaged. Therefore, it is possible to prevent a defective seal caused by the damage to the grommet 23. for that reason,
The durability of the seal between the cylinder head 3 and the cylinder block 5 can be improved.

Embodiment 2 In this embodiment, as shown in FIG. 6, eight projections 54 are provided at intervals. Other configurations are the same as those of the first embodiment. This embodiment also has the same operation and effect as the first embodiment.

Third Embodiment As shown in FIG. 7, this embodiment is different from the projection 53 of the first embodiment.
The outer peripheral surface 539 is inclined. The protrusion 55 of the present example has a substantially right triangle cross section. In addition,
The height H of the protrusion 55 in this example is the height h of the protrusion 53.
Is equal to In addition, on the outer peripheral surface 559 of the projection 55,
The inner peripheral surface 231 of the grommet 23 of the gasket 2 is disposed to face. Other configurations are the same as those of the first embodiment.

In this embodiment, since the outer peripheral surface 559 is inclined, when the inner peripheral surface 231 of the grommet 23 comes into contact with the outer peripheral surface 559, the contact area can be increased. Therefore, there is an effect that damage to the grommet 23 can be prevented. Others have the same operation and effects as the first embodiment.

Fourth Embodiment In this embodiment, as shown in FIG. 8, a protrusion is formed by a cylinder liner 6 disposed on the inner wall of the cylinder 50. Other configurations are the same as those of the first embodiment. In this embodiment, the upper end surface 67 of the cylinder liner 6 is disposed so as to protrude from the upper end surface 57 of the cylinder block 5 toward the cylinder head 3 by 50% of the thickness t of the gasket 5. The upper end of the cylinder liner 6 can be a projection 63. Therefore, the projection 63 can be easily formed. Others have the same operation and effects as the first embodiment.

In addition, the cylinder head 3 may be provided with the above-mentioned projection projecting toward the cylinder block 5 at a position facing the periphery of the opening 51 of the cylinder 50. Further, the protrusions may be provided on both the cylinder block 5 and the cylinder head 3.

[0039]

As described above, according to the present invention, it is possible to prevent the protrusion of the gasket and to provide an engine seal structure having excellent seal durability between the cylinder head and the cylinder block.

[Brief description of the drawings]

FIG. 1 is a sectional view of an engine seal structure according to a first embodiment.

FIG. 2 is a cross-sectional view illustrating a periphery of a seal structure according to the first embodiment.

FIG. 3 is an explanatory view showing an arrangement position of a protrusion according to the first embodiment.

FIG. 4 is a perspective view of a protrusion according to the first embodiment.

FIG. 5 is a plan view of a gasket according to the first embodiment.

FIG. 6 is a perspective view of a protrusion of a seal structure according to a second embodiment.

FIG. 7 is a sectional view of a seal structure according to a third embodiment.

FIG. 8 is a sectional view of a seal structure according to a fourth embodiment.

FIG. 9 is a cross-sectional view of a conventional engine seal structure.

FIG. 10 is a cross-sectional view for explaining protrusion according to a conventional example due to deformation of a gasket.

FIG. 11 is a sectional view taken along the line AA in FIG. 10;

FIG. 12 is a cross-sectional view illustrating protrusion by deformation of a grommet according to a conventional example.

[Explanation of symbols]

 1. . . 1. Engine seal structure, . . Gasket, 20. . . Gasket holes, 21. . . Base material, 22. . . Wiring, 23. . . Grommet, 3. . . 4. cylinder head, . . Cylinder block, 50. . . Cylinder, 51. . . Openings, 53-55. . . Protrusions, 6. . . Cylinder liner, 63. . . 6. protrusions, . . Boa,

Claims (5)

[Claims] In an engine seal structure comprising a cylinder head, a cylinder block having a plurality of cylinders, and a gasket disposed between the cylinder head and the cylinder block, the gasket communicates between the cylinder head and the cylinder block. A base material having a plurality of gasket holes to be formed, and a grommet having a U-shaped cross section for sealing the periphery of the gasket holes. At least one of the cylinder block and the cylinder head has a peripheral edge of an opening of the cylinder. A grommet of the gasket, wherein an inner peripheral surface of the grommet is opposed to an outer peripheral surface of the projection. 2. The seal structure for an engine according to claim 1, wherein the protrusions are disposed at openings of cylinders located at both ends of the plurality of cylinders. 3. The seal structure for an engine according to claim 1, wherein the protrusion is formed by a cylinder liner disposed on an inner wall of the cylinder. 4. The method according to claim 1, wherein:
The seal structure for an engine, wherein the protrusion is provided in an annular shape. 5. The method according to claim 1, wherein:
A seal structure for an engine, wherein a plurality of the protrusions are provided at intervals.