JP2022150885A - Sealing structure of three-face mating part - Google Patents

Abstract

To provide a sealing structure of a three-face mating part which can improve the seal performance of the three-face mating part while suppressing the enlargement of a seal face.SOLUTION: A sealing structure of a three-face mating part of a cylinder head of an internal combustion engine, a cylinder block and a chain cover comprises a structure body. The structure body holds an accessory component of a timing chain accommodated in a chain cover, is interposed between and among the cylinder head, the cylinder block and the chain cover, and arranged so as to straddle the cylinder head and the cylinder block. Then, the structure body includes a wall part and an elastic part. The wall part has a seal face for sealing a clearance between the chain cover and itself via a chain cover gasket. The elastic part is arranged in a recess which is formed at the wall part at a side opposite to the seal face, and seals the three-face mating part.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a sealing structure for a three-face joint of an internal combustion engine.

Patent Literature 1 discloses a sealing structure for a three-face joint between a cylinder head, a cylinder block, and a chain cover of an internal combustion engine. A chain cover gasket including an elastic receiving portion made of rubber is arranged at the three-sided joint.

JP 2011-226641 A

In the sealing structure of the three-face mating portion described in Patent Document 1, when a step due to the temperature difference between the cylinder head and the cylinder block occurs between the cylinder head side seal surface and the cylinder block side seal surface, There is a concern that deterioration of the elastic receiving portion described above will progress. In order to avoid such problems, it is conceivable to adopt the following sealing structure (for example, Comparative Example 2 described later).

That is, a space extending over the cylinder head and the cylinder block is provided so as not to produce a three-sided joint. A first chain cover that covers (closes) the space is provided. A second chain cover is provided to cover the first chain cover while accommodating accessories of the timing chain between the first chain cover and the second chain cover. However, if such a sealing structure is adopted, it is necessary to provide sealing surfaces between the cylinder head/cylinder block and the first chain cover and between the first chain cover and the second chain cover. As a result, the sealing surface is increased compared to the case where there is only one chain cover.

The present disclosure has been made in view of the problems described above, and an object of the present disclosure is to provide a sealing structure for three-surface mating portions that is capable of improving the sealing performance of the three-surface mating portions while suppressing an increase in the number of sealing surfaces. and

A sealing structure for a three-faced joint according to the present disclosure is a sealing structure for a three-faced joint between a cylinder head, a cylinder block, and a chain cover of an internal combustion engine, and includes a structure.
The structure holds attachments of the timing chain housed inside the chain cover, is interposed between the cylinder head and the cylinder block and the chain cover, and is arranged to straddle the cylinder head and the cylinder block. .
The structure includes a wall portion and an elastic portion. The wall has a sealing surface that seals with the chain cover via a chain cover gasket. A resilient portion is disposed in a recess formed in the wall opposite the sealing surface to seal the three-sided joint.

According to the sealing structure of the three-faced joint according to the present disclosure, only one chain cover is required. You can control the increase. Also, the three-sided mating portion is sealed by the elastic portion of the structure. Here, compared to the chain cover gasket in a general example in which the chain cover gasket is arranged in the gap between the cylinder head/cylinder block and the chain cover, the elastic portion arranged in the recess formed in the wall portion has a thickness. easy to secure. Therefore, according to the elastic portion, it is possible to satisfactorily absorb the step at the three-faced portion caused by the temperature difference between the cylinder head and the cylinder block, so that the sealing performance of the three-faced portion can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram schematically showing an example of a configuration of an internal combustion engine to which a three-face sealing structure according to an embodiment is applied; 2 is a diagram for explaining the configuration of the structure shown in FIG. 1; FIG. 2 is a diagram schematically showing the configuration of an internal combustion engine according to Comparative Example 1; FIG. FIG. 5 is a diagram schematically showing the configuration of an internal combustion engine according to Comparative Example 2;

Embodiments of the present disclosure will be described below with reference to the accompanying drawings. When referring to numbers such as the number, quantity, amount, range, etc. of each element in the embodiments shown below, unless otherwise specified or clearly specified in principle, the number referred to However, the technical idea according to the present disclosure is not limited to this. In addition, the structures and the like described in the embodiments shown below are not necessarily essential to the technical idea according to the present disclosure, unless otherwise specified or clearly specified in principle.

1. 1. Sealing Structure for Three-Facing Joint FIG. 1 is a diagram schematically showing an example of the configuration of an internal combustion engine 10 to which a three-face-joining sealing structure according to an embodiment is applied. Internal combustion engine 10 includes a cylinder head 12 , a cylinder block 14 and a chain cover 16 . The cylinder head 12 is attached to the top of the cylinder block 14 via a head gasket 18 .

A cam carrier 20 that supports a camshaft (not shown) is attached to the upper portion of the cylinder head 12 . A head cover 22 is attached to the top of the cam carrier 20 and the top of the chain cover 16 . A crankcase 24 is attached to the lower portion of the cylinder block 14 . An oil pan 26 is attached to the lower portion of the crankcase 24 . Note that the cam carrier 20 may be formed integrally with the cylinder head 12 . Also, the crankcase 24 may be formed integrally with the cylinder block 14 .

Chain cover 16 is attached to cylinder head 12 , cylinder block 14 , cam carrier 20 and crankcase 24 via chain cover gasket 28 . More specifically, the chain cover 16 is fastened to each of these cylinder heads 12 and the like using bolts (not shown). The chain cover gasket 28 is represented by dashed lines in FIG. The chain cover gasket 28 is, for example, a FIPG (Formed In Place Gasket). Also, the chain cover gasket 28 may be a liquid gasket other than FIPG, or may be a rubber gasket, for example.

In addition, the internal combustion engine 10 to which the sealing structure of the three-faced portion of the present embodiment is applied includes the structure 30 .

Specifically, the structure 30 holds attachments for a timing chain (not shown) that is housed inside the chain cover 16 . More specifically, the attachments are attached to structure 30 by, for example, bolts (not shown). The accessories here are, for example, a chain tensioner 34 and a chain damper 36 shown in FIG. 2 which will be described later. A chain tensioner 34 adjusts the tension of the timing chain. A chain damper 36 guides the timing chain. Also, the attachments held by structure 30 may be one of chain tensioner 34 and chain damper 36, or may include other attachments.

As shown in FIG. 1 , the structure 30 is interposed between the cylinder head 12 and the cylinder block 14 and the chain cover 16 and is arranged to straddle the cylinder head 12 and the cylinder block 14 . In other words, the structure 30 is arranged at the three-face joint portion 1 of the cylinder head 12 , the cylinder block 14 and the chain cover 16 . A specific configuration example of the structure 30 will be described later with reference to FIG.

Although the gap 32 between the cylinder head 12 and the cam carrier 20 and the chain cover 16 shown in FIG. The gap 32 is designed to appear when the internal combustion engine 10 is cold and disappear due to the difference in thermal expansion due to the temperature difference between the cylinder head 12 and the cylinder block 14 when the internal combustion engine 10 is warm.

FIG. 2 is a diagram for explaining the configuration of structure 30 shown in FIG. FIG. 2A is a view of the structure 30 viewed from the direction indicated by arrow A in FIG. 1 (crankshaft direction from the chain cover 16 side). 2(B) and 2(C) are views of the structure 30 shown in FIG. 2(A) viewed from above and from the right side of the paper, respectively.

The structure 30 includes a plate-like base 30a and a pair of ends 30b and 30c. The base 30a connects between the ends 30b and 30c. More specifically, the pair of ends 30b and 30c are provided at both ends of the structure 30 in a direction B (horizontal direction of the drawing) parallel to the mating surfaces of the cylinder head 12 and the cylinder block 14, respectively. The structure 30 is fastened to both the cylinder head 12 and the cylinder block 14 by bolts (not shown) using bolt holes 30a1 and 30a2 formed in the base portion 30a. More specifically, the bolt holes 30a1 (two as an example) are for fastening to the cylinder head 12, and the bolt holes 30a2 (two as an example) are for fastening to the cylinder block .

Both ends 30b and 30c of the structure 30 are formed by a wall portion 38 and an elastic portion 40, respectively.

Specifically, the wall portion 38 has a seal surface 38 a that seals with the seal surface 16 a of the chain cover 16 via the chain cover gasket 28 . More specifically, as shown in FIG. 2A, the sealing surfaces 38a are provided at both ends 30b and 30c so as to extend in a direction C parallel to the cylinder axis of the internal combustion engine 10 (vertical direction on the paper surface). It is In addition, in the structure 30, the wall portion 38 and the base portion 30a are formed integrally or separately using a metal material such as aluminum.

In addition, as indicated by broken lines in FIG. 1, the chain cover gasket 28, excluding the portion of the chain cover 16 on the side of the head cover 22, includes the seal surface 16a on the chain cover 16 side, the cam carrier 20, and the cylinder head. 12, the structure 30, the cylinder block 14, and the crankcase 24 are entirely sealed with their respective sealing surfaces (including the sealing surface 38a). As a result, a sealed space is formed inside the chain cover 16 in which housing components such as the timing chain and its accessories (chain tensioner 34, etc.) are arranged.

As shown in FIG. 2(C), the elastic portion 40 is arranged in a concave portion 38b formed in the wall portion 38 on the opposite side of the sealing surface 38a, and seals the three-sided portion 1. As shown in FIG. As a result, the chain cover gasket 28 itself can be prevented from sealing the three-face contact portion 1 . The elastic portion 40 is configured using, for example, a rubber material, but an elastically deformable member other than rubber may be used. The elastic portion 40 may be integrally molded with the wall portion 38 or may be molded separately from the wall portion 38 .

More specifically, each elastic portion 40 faces the three-sided portion 1 . By fastening the structure 30 to the cylinder head 12 and the cylinder block 14 , each elastic portion 40 is pressed against the cylinder head 12 and the cylinder block 14 to seal the three-faced portion 1 .

Further, as shown in FIGS. 1 and 2C (more specifically, when viewed from the normal direction of a plane including the crankshaft and the cylinder , has a trapezoidal shape that is convex toward the chain cover 16 side. That is, the seal surface 38a is formed with a slope. The chain cover 16 has a shape along the trapezoidal wall portion 38 . Since the seal surface 38a has a trapezoidal shape with slopes instead of a quadrilateral shape when viewed in the normal direction, the entire seal surface 38a can be used to attach the chain cover 16 to the seal surface 16a. and the sealing surface 38a, the chain cover gasket 28 can be evenly crushed. However, the sealing surface 38a for obtaining such an effect may use, for example, an arc shape with an arbitrary curvature instead of the flat inclined surface.

2. Effect Hereinafter, the effect of the sealing structure of the three-faced portion 1 according to the present embodiment will be described with reference to Comparative Examples 1 and 2. FIG.

FIG. 3 is a diagram schematically showing the configuration of an internal combustion engine 100 according to Comparative Example 1. As shown in FIG. The internal combustion engine 100 according to Comparative Example 1 differs from the internal combustion engine 10 of the present embodiment in that a chain cover 102 is provided instead of the chain cover 16 and the structure 30 . The three-face contact portion 2 of this internal combustion engine 100 is sealed with a chain cover gasket 104 (for example, FIPG). With such a configuration, when a step due to a temperature difference between the cylinder head 12 and the cylinder block 14 occurs between the seal surface on the cylinder head 12 side and the seal surface on the cylinder block 14 side, the chain cover There is a concern that deterioration of the gasket 104 progresses.

FIG. 4 is a diagram schematically showing the configuration of an internal combustion engine 200 according to Comparative Example 2. As shown in FIG. The internal combustion engine 200 according to Comparative Example 2 differs from the internal combustion engine 10 of the present embodiment in the following points. That is, internal combustion engine 200 includes first and second chain covers 202 and 204 . In addition, the cylinder head 206 and the cylinder block 208 have a space 210 formed across the cylinder head 206 and the cylinder block 208 at the end on the side facing the first chain cover 202 . This space 210 is formed in order to eliminate the three-sided joint between the cylinder head 206 , the cylinder block 208 and the first chain cover 202 .

The first chain cover 202 has a wall portion 202a that covers the space 210, and is overlapped with the cylinder head 206, the cylinder block 208, the cam carrier 20, and the crankcase 24 via the first chain cover gasket 212. there is On the opposite side of the first chain cover 202 to the side of the cylinder head 206 and the like, housing parts (not shown) such as a timing chain and its attached parts (for example, a chain tensioner and a chain damper) are arranged. The second chain cover 204 covers the first chain cover 202 while accommodating the accommodated parts, and overlaps the first chain cover 202 via the second chain cover gasket 214 .

According to Comparative Example 2 described above, it is possible to avoid the problem of deterioration of the chain cover gasket 104, which is faced by Comparative Example 1, by eliminating the three-faced joint. However, it is necessary to close the space 210 by using the wall portion 202a of the first chain cover 202 . For this reason, the second chain cover 204 is required to dispose the components such as the timing chain outside the first chain cover 202 (that is, on the opposite side of the space 210) and to cover the components. As a result, the sealing surface of the entire chain cover increases. Also, this leads to an increase in cost.

On the other hand, according to the sealing structure of the three-faced portion 1 of the present embodiment, only one chain cover 16 is required. It is possible to suppress the increase in the sealing surface of Also, the three-face mating portion 1 is sealed by the elastic portion 40 of the structure 30 . Compared to the chain cover gasket 104 arranged in the gap between the cylinder head 12 and the cylinder block 14 and the chain cover 102 in Comparative Example 1, the elastic portion 40 arranged in the concave portion 38b formed in the wall portion 38 secures a thickness. easy to do Therefore, the elastic portion 40 can satisfactorily absorb the step of the three-faced portion 1 caused by the temperature difference between the cylinder head 12 and the cylinder block 14, so that the sealing performance of the three-faced portion 1 can be improved. In addition, the cost of the chain cover can be reduced without compromising sealing performance.

Also, the structure 30 that holds the timing chain accessories (for example, the chain tensioner 34 and the chain damper 36) is in contact with the cylinder head 12 and the cylinder block 14 via the elastic portion 40 at the pair of ends 30b and 30c. ing. As a result, an effect of reducing vibration noise can be expected due to damping of vibrations from the timing chain and its attached parts.

3. REFERENCE EXAMPLE In the sealing structure of the three-sided portion according to the reference example related to the present disclosure, the structure for holding the attachment parts of the timing chain does not have an elastic portion, unlike the structure 30 shown in FIG. good too. A liquid gasket such as FIPG may be used to seal between the structure and the cylinder head and cylinder block. Also in this reference example, the sealing surfaces between the chain cover/structure and the cylinder head/cylinder block can be reduced as compared with Comparative Example 2 described above. Therefore, the cost for managing the seal surface can be reduced.

1 Three-sided portion 10 Internal combustion engine 12 Cylinder head 14 Cylinder block 16 Chain cover 16a Chain cover sealing surface 20 Cam carrier 22 Head cover 24 Crankcase 26 Oil pan 28 Chain cover gasket 30 Structure 32 Gap 34 Chain tensioner 36 Chain damper 38 Structure body wall 38a structure wall sealing surface 38b structure wall recess 40 structure elastic part

Claims (1)

A sealing structure for a three-sided joint between a cylinder head, a cylinder block and a chain cover of an internal combustion engine,
The sealing structure holds a timing chain accessory housed inside the chain cover, is interposed between the cylinder head and the cylinder block and the chain cover, and is between the cylinder head and the cylinder block. With a structure arranged to straddle,
The structure is
a wall portion having a sealing surface that seals with the chain cover via a chain cover gasket;
and an elastic portion arranged in a recess formed in the wall portion on the opposite side of the sealing surface to seal the three-faced portion.

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