JPS6047851A - Exhaust manifold gasket - Google Patents

Abstract

PURPOSE:To improve the productivity as well as the incorporating property of a gasket capable of absorbing the difference of thermal expansion by a method wherein the gasket is formed in the shape of multiple layers excluding the gasket employed between cylinders whereat the thermal expansion of the gasket is large while one-ply of gasket, employed between the cylinders, is relaxed. CONSTITUTION:The gasket 14 is arranged between a cylinder head 10 and the exhaust manifold 12 while the exhaust manifold 12 is attached to the screw holes 15 of the cylinder head 10 through bolts 18 pinching the gasket 14. In this case, the gasket 14, employed between exhaust ports 10-3, 10-4 which are communicated with third and fourth cylinders having large thermal expansions, is formed into single-ply while the gasket employed for other parts is formed into multi-layers. The first layer 14a of the gasket 14 is provided with size and shape covering the whole of the cylinders while the other parts of the gasket, corresponding to the exhaust ports 10-1-10-3, 10-4 communicated with the cylinders from the first to the third and fourth, are formed into the multiple layers by laminating the layers after second layer. Further, the first layer 14a, which is single-ply, is relaxed as shown by the numeral 14a-1.

Description

Description: TECHNICAL FIELD The present invention relates to a gasket structure disposed on a mounting surface between an exhaust manifold and a cylinder head in an internal combustion engine.

A gasket 1-, which is installed on the side surface between the exhaust manifold and the cylinder head of a prior art internal combustion engine, is made of metal in consideration of heat resistance against the high-temperature exhaust manifold. In this case, it has been conventionally known to form the gasket into a laminated structure in order to improve sealing performance. In this case, if the cylinders of the engine are compared, the thermal expansion may vary in size, for example, if the engine is equipped with a turbocharger. That is, depending on the position where the turbocharger is installed, the heat from the turbocharger is concentrated in one specific cylinder and is transmitted, resulting in large thermal expansion between the cylinder and the adjacent cylinder. Therefore, in order to prevent gasket damage by absorbing thermal expansion, a structure is adopted in which the gas cap is separated between cylinders with large thermal expansion, or the gasket is loosened between cylinders with large thermal expansion. It is being carried out. but,
In the case of the previous model, since it has a structure with separation, the assembly (; In addition, the strength becomes too large, making it difficult to use as a means of loosening.

OBJECTS OF THE INVENTION In view of the drawbacks of the prior art, it is an object of the present invention to provide a laminated gasket structure that can improve both ease of assembly and productivity.

Structure of the Invention In the exhaust manifold gas exhaust system of the present invention, the gasket is constructed in multiple layers except between the cylinders where the thermal expansion is large, and one gasket between the cylinders where the thermal expansion is large is given slack. ing. In addition, each layer is held together by connecting means such as rivets.

Embodiment In FIG. 1, 1o is a cylinder head of an internal combustion engine;
2 is an exhaust manifold, and mounting surfaces 10 facing each other
', 12'. This internal combustion engine has four cylinders, and there are four exhaust bows 1-10 in the cylinder head.
-1, 10-2, 10-3, 10-4, while the exhaust manifold 12 has correspondingly four branch pipes 12.
-1, 12-2, 12-3, and 12-4. A gasket 14 is located between the cylinder head 10 and the exhaust manifold I2, and the gasket 14 is placed between the cylinder head 10 and the exhaust manifold Pzepol 1 in the screw hole 5 of the cylinder head 1o.
It is installed t3 by ~18. The gaskets keep the exhaust boats 10-1, 10-2, 10-3, and 10-4 sealed from the outside and connect the corresponding exhaust manifold branch pipes 12-.
1.

It serves to communicate with 12-2, 12-3, and 12-4. In the present invention, the gasket is formed by laminating metal plates to improve sealing performance. However, if the gaskets are simply laminated and there is a difference in thermal expansion between the layers, the gasket will not be able to follow such a difference in thermal expansion coefficient, resulting in damage to the gasket. That is, the internal combustion engine of the present invention is equipped with a turbocharger, and the turbocharger is installed above the fourth cylinder. Since the heat load of the turbocharger is large, the thermal expansion of the exhaust manifold portion 12-4 below it is larger than that of the other parts 1 to 3.
It will be larger in comparison with the second. As a result, the gasket 14 expands greatly between the third and fourth cylinders, and cannot absorb the expansion. Therefore, during this time, gasket 1-
Part 14 may be damaged.

In order to deal with this problem, the gasket of the present invention has a single layer between the third and fourth cylinders, where thermal expansion is large, and a multilayer between the third and fourth cylinders. There is slack in that one gasket in between. That is, to explain the structure of such a gasket in more detail with reference to FIG. 3, 14a is the first layer of gasket, which has dimensions that cover the entirety of the first to fourth cylinders.

It has a shape. Numeral 14b is a seal plate dedicated to the fourth cylinder, and a plurality (4) of them are stacked on the first layer 14a, which is common to each cylinder. 20 and 22 are beam vents that hold them together in assembly.

On the other hand, the second and subsequent layers of the first to third cylinders are made by stacking the plates 14c, and similarly the rivets 2
8 and 30 are mutually concluded. As a result, the gasket l
-14 constitutes one assembly as a whole, thereby improving ease of assembly. In the assembled state, the gasket 14 has a hole 32 through which the port 18 for attaching the exhaust manifold 12 to the cylinder head 10 passes, and holes 34-1, 34-2, 34-3 through which exhaust gas from each cylinder passes.
, 34-4.

According to the present invention, the metal plate of the first layer between the third and fourth cylinders, which have a large thermal expansion, is provided with a slack 148-1. Due to this slackness, 9:jl! It is intended to absorb expansion.

As shown in FIG. 4(a), a rectangular bead 40 is provided on the metal plate of the upper layer and the third layer. This bead 40 has holes 34-1, 34-2, 34 through which exhaust gas passes.
-3 and 34-4 so as to surround the entire circumference thereof.

During assembly, this bead 40 improves the sealing performance to the opposing cylinder head wall surface 10' and the opposing gasket 1 surface, thereby providing good sealing performance.

According to the gasket structure of the present invention, the third gasket with large thermal expansion
Gasket 1- between the 1st and 4th Fi14
Only a is left, and there is a slack 14a-] between the two. H: C: During expansion, this loosening allows the gasket 14 to extend and prevents excessive force from being applied to it. Therefore, no damage occurs.

FIG. 4(b) shows the structure of #4 camphor in another embodiment, in which another thin metal plate 14d is provided second from the bottom, resulting in a six-plate structure.

On the other hand, #I-#3 has a five-layer structure, which is the same as in FIG. 4(A).

Effects of the Invention Productivity is improved by constructing the cylinders in multiple layers except for those between the cylinders where thermal expansion is large, by allowing one layer of slack between the cylinders, and by combining each layer into a single assembly using connecting means such as lees and sotos. It has good performance and does not impair assemblability in the slightest, and even if there is a difference in thermal expansion, it can be absorbed.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the gasket structure of the present invention before assembly between the cylinder head and the exhaust manifold, Fig. 2 is a front view of the gasket of the present invention, and Fig. 3 is a direction shown in Fig. 2 in the ■ direction. FIG. 4 is an enlarged top view showing the structure of each layer of the gasket of the present invention. DESCRIPTION OF SYMBOLS 10... Cylinder head, 12... Exhaust manifold, 14... Gasket, 14a... First darkness, 14b
, 14c... 2nd 5 N, 14a-1-= slack. Patent applicant: Toyota Motor Corporation ωJ Vehicle Co., Ltd. Japan Gasket Co., Ltd. Patent agent: Akira Aoki, patent attorney: Kazuyuki Nishidate, patent attorney: Takao Mitsui, patent attorney: Akira Yamaguchi, patent attorney: Masaru Nishiyama] Figure 2, Figure 1゜32 Horn Figure 3 Figure 4 4Q

Claims (1)

[Claims] In the exhaust manifold gasket placed on the mounting surface between the exhaust manifold and the cylinder head, the gasket is constructed in multiple layers except between the cylinders where thermal expansion is large, and the single gasket between the cylinders where thermal expansion is large is made to have slack. Exhaust manifold gasket structure in which each layer is assembled into one assembly by connecting means.