JPH1061489A - Seal structure for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve sealing property in fitting state with an engine body and a chain cover. SOLUTION: A plurality of seal grooves 8 are formed on a fitting surface 6 peripheral of a chain cover 1 to a joining surface (t) opposite to the chain cover 1 of a joining surface (s) with a cylinder block and a cylinder head and width of seal groove 9 formed at a position where a fitting bolt hole 7 is apart from the joining surface part t of the seal grooves set wider in a position close at the joining surface part side. Sealing agent (m) may be piled up on the wider position of the seal groove 9 by filling it more than usual the sealing agent (m) may be filled in a space even if the space due to a cavity at mounting of the chain cover 1 is a little larger than usual. A conventional chain cover 1 can be utilized, so that its cost can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION Some engines mounted on automobiles are equipped with a valve drive and connected by a timing chain. Since the chain cover that protects and stores the device is mounted over the cylinder head and the cylinder block, the accuracy of the mounting surface and the application of the sealant are accurately performed. The present invention relates to a seal structure of an internal combustion engine at a place where the chain cover is attached or the like.

[0002]

2. Description of the Related Art Conventionally, when a chain cover is attached to an engine body consisting of a cylinder head and a cylinder block, as shown in FIG. And are connected by bolts 4. Also, the cylinder block 2 and the cylinder head 3 are joined to each other at a joint surface s.
Are connected by bolts (not shown) with a head gasket 5 (see FIG. 6) interposed therebetween. The chain cover 1 is configured so that the peripheral mating surface 6 shown in FIGS.

Further, as shown in FIG. 9, a sealing groove 8 is formed in addition to a bolt hole 7 on the mating surface 6 on the peripheral edge of the chain cover 1, and the sealing groove 8 has a constant groove width W and depth D. It is provided intermittently over the entire circumference. When the sealing agent m is filled into the sealing groove 8 so as to be raised, and the mating surface 6 is joined to the mounting surface of the engine body, the sealing agent m is crushed, and the sealing agent m flows into a gap due to a slight dimensional error. To improve hermeticity. The sealing in this way prevents the oil in the cover from leaking to the outside. Further, Japanese Utility Model Laid-Open No. 4-110347 discloses a structure in which an oil pump body is disposed so that an upper end thereof is aligned with a cylinder block, and is in contact with a head gasket at an upper end. When the oil pump body thermally expands, the head gasket is lifted. The state is maintained and the sealing property is maintained.

[0004]

By the way, as shown in FIG. 6, each end face of the cylinder block 2 and the cylinder head 3 has a stepped portion p at the joint surface portion t at the time of mounting due to a variation in manufacturing tolerance. The sealing agent m flows into this portion and fills the gap, so that the sealing property is maintained. However, the pitch a between the head gaskets of the tightening bolts 4a for fixing the cylinder head 3 is shorter than the pitch b between the head gaskets of the tightening bolts 4b for fixing the cylinder block 2, and the tightening force varies greatly. In some cases, the surface pressure of the mating surface 6 of the chain cover 1 may not be substantially uniform. For this reason, when the sealant m may be affected by the vibration during the operation of the engine, it is necessary to check the sealability many times.

[0005] In addition, it is possible to reduce the complicated inspection work, align the position of the tightening bolt 4b of the cylinder block 2 with the cylinder head 3, and arrange the tightening bolt 4a at a position symmetrical to the tightening bolt 4a around the joint surface t. Although it is conceivable, the cost is increased because the chain cover 1 on the mating surface side is redesigned or has a structure that maintains strength, and the number of parts increases.
It is not a good idea.

[0006] The present invention does not change the cover shape,
It is an object of the present invention to provide a seal structure of an internal combustion engine which can improve the sealability without increasing the number of parts and cost.

[0007]

According to the present invention, in order to achieve the above object, a chain cover is mounted on a mounting surface at an end of an engine body in which a cylinder block and a cylinder head are joined, and a gap is filled with a sealant. In the seal structure of an internal combustion engine, a seal groove is formed on a mating surface provided along the periphery of the chain cover, and the width and depth of the seal groove are closer to the joint surface between the cylinder block and the cylinder head. It is characterized by being formed large.

[0008] Further, the present invention is characterized in that ribs which divide the groove width and extend in the groove direction are provided at locations where the groove width and depth of the seal groove are increased.

Further, of the tightening bolts for mounting the chain cover on the mounting surface between the cylinder block and the cylinder head, the former or latter seal groove is formed on the side where the distance between the joint surface of the cylinder and the tightening bolt is longer. It is characterized by having been provided.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS When a chain cover is mounted on a mounting surface of an engine body, a sealing agent is applied to a mating surface provided along a peripheral edge of the chain cover. At this time, a portion having a wide groove width can be filled high, and a portion having a groove depth can easily hold the raised height. Therefore, when the chain cover is fitted, the sealant flows even in a gap larger than the normal gap, so that the sealant is filled in a large amount, so that the sealant can be reliably filled. Also, the screw can be tightened so strongly that no distortion occurs.

In addition, due to the mounting structure of the chain cover, if the distance from the joint surface of the cylinder to each of the tightening bolts is long, a step is likely to be formed on the mating surface, and it is difficult to absorb the tightening force. Therefore, a seal groove having a large groove width and a large groove depth is formed on the side where the distance between the joint surface of the cylinder and the tightening bolt is long, and a large amount of sealant is used. Thereby, the gap is filled.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings. As shown in FIGS. 1 and 2, the chain cover 1
A bolt hole 7 and seal grooves 8 and 9 are provided in the mating surface 6 of. The joining surface s where the cylinder head 2 and the cylinder block 3 overlap each other forms a joining surface portion t linearly on the mounting surface at the end. The bolt hole 7 formed on the cylinder block 2 side is located farther from the joint surface t than the bolt hole 7 formed on the cylinder head 3 side of the chain cover 1.

The cylinder block 2 closest to the joining surface t
The width of the seal groove 9 on the side becomes wider as it is closer to the joint surface portion t, and the groove width W1 of the closer seal groove 9 is larger than the groove width W2 of the distant groove. Further, as shown in FIG. 2, the depth D1 of the groove closer to the bonding surface t is larger than the depth D2 of the groove farther.

By forming the seal grooves 8 and 9 of the chain cover 1 in this manner, the amount of the sealing agent m filled in the seal groove 9 closest to the joint surface portion t can be held larger than in the conventional case. As shown in FIG. 2, the sealing agent m can be raised on the mating surface 6 more than before. When the chain cover 1 is mounted on the engine body with the bolts 4 and the bolts 4a and 4b, the end on the cylinder block 2 side using the bolts 4b is retracted so that a step p is formed in the joint surface t.

In the structure of the present invention, even when the step p at the joining surface t between the cylinder block 2 and the cylinder head 3 becomes large, the step p is filled with the sealing agent m and the joining surface t
Sealability is improved. Further, since the width W and the depth D of the seal groove 8 formed in the conventional chain cover 1 are only partially increased, the strength of the cover is not affected, the number of parts is not increased, and the cost is reduced. It can be easily implemented without up. Further, in response to vibration, the thickness and width of the sealant m are increased, so that the vibration resistance is improved and the life is extended.

The wide seal groove 9 provided with a rib 10 at the center thereof will be described with reference to FIGS. The rib 10 extending from the joint surface side end of the seal groove 9 to the intermediate portion divides the groove width into two, and the sealant m is raised over the two-divided groove at the time of filling. In this case, the gap at a position near the joining surface t of the mating surface 6 on the periphery of the chain cover is easily filled, and the sealing performance is improved. Further, the strength of the rib 10 and the swelling of the sealant by the rib 10 are facilitated, the rigidity of the mating surface 6 is increased, and the surface pressure is improved. This configuration can be easily implemented because the number of parts does not change and the cost does not change much.

[0017]

As described above, the present invention is constructed as described above, so that there is a place where a larger amount of sealant is provided on the mating surface of the chain cover than before, and the sealant is formed on the step formed on the mounting surface with the engine body. Can be sufficiently filled, distortion at the time of mounting can be reduced, and sealing performance can be improved. In addition, the life of each part is extended. In addition, since the size of the seal groove on the mating surface is merely changed, the number of parts and the cost are the same as those of the related art, and it can be easily implemented. Further, by providing the rib in the seal groove, the rigidity is increased, and the surface pressure and the sealability can be improved. Further, the seal groove is provided only in the cylinder block and the cylinder head where the distance between the joint surface portion and the bolt is longer, and the change operation is simple, so that the seal groove is widely used.

[Brief description of the drawings]

FIG. 1 is a partial back view of a chain cover according to an embodiment of the present invention.

FIG. 2 is a partial side view of the chain cover shown in FIG.

FIG. 3 is a partial rear view of a chain cover according to another embodiment.

FIG. 4 is a partial side view of the chain cover shown in FIG. 3;

FIG. 5 is a sectional view taken along line AA shown in FIG. 3;

FIG. 6 is a partial side view of a conventional chain cover.

FIG. 7 is a front view of a conventional engine body and a chain cover.

FIG. 8 is a rear view of the chain cover shown in FIG. 7;

FIG. 9 is a partial back view of the chain cover shown in FIG. 7;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Chain cover 2 Cylinder block 3 Cylinder head 4a, 4b Tightening bolt 6 Fitting surface 9 Seal groove 10 Rib m Sealant t Joint surface

Claims (3)

[Claims] 1. A seal structure of an internal combustion engine in which a chain cover is mounted on an attachment surface of an end portion of an engine body in which a cylinder block and a cylinder head are joined, and a gap is filled with a sealant. A seal groove is formed on the mating surface provided by the step (c), and the width and depth of the seal groove are formed larger as approaching the joint surface between the cylinder block and the cylinder head. 2. A seal for an internal combustion engine, wherein a rib that divides the groove width and extends in the groove direction is provided at a position where the groove width and the depth of the seal groove according to claim 1 are increased. Construction. 3. A tightening bolt for mounting a chain cover on a mounting surface between a cylinder block and a cylinder head, the tightening bolt having a longer distance between a joint surface of the cylinder and the tightening bolt. A seal structure for an internal combustion engine, wherein the seal groove is provided.