STEEL LAMINATE GASKET WITH WIDE SEALING AREA

Abstract: A steel laminate gasket of the invention is installed in an internal combustion engine having at least one hole therein. The gasket comprises a first plate and a second plate situated under the first plate. The first plate includes at least one first hole corresponding to the hole of the engine, a base portion, at least one curved portion and at least one flange situated above the base portion. The curved portion and flange are integrally formed with the base portion. A side wall is formed on one of the base portion and the flange to form an embossed portion thereat. Also, a bead is formed on the embossed portion to thereby provide a sealing pressure stronger than the embossed portion when the gasket is tightened.

Description: The invention relates to a steel laminate gasket for an internal combustion engine having at least one hole therein, said gasket comprising a first plate having a first hole corresponding to the hole of the engine and a base portion, and a second plate situated adjacent to the first plate and having a second hole larger than the first hole, said first plate includes at least one curved portion integrally formed with the base portion to extend transversely thereto to define the first hole, at least one flange integrally formed with the curved portion and being located at a side of the base portion to extend substantially parallel to the base portion. Particularly, the present invention relates to a steel laminate gasket for an internal combustion engine, which can provide wide and high sealing pressure to securely seal around a hole. The steel laminate gasket of the present invention may be used widely,such as a regular gasket situated between two engine blocks, cylinder head gasket and manifold gasket. When the gasket of the present invention is used as a cylinder head gasket, the gasket may seal around cylinder holes Hc, water holes Hw, oil holes Ho, bolt holes Hb and the like, as shown in Fig. 1. However, it is preferably to seal around a relatively large hole, such as a cylinder hole Hc. In a gasket, a main subject of a gasket is to securely seal around a hole. Therefore, when a gasket is designed, attention has been paid how a portion around a hole is securely sealed. In this respect, there have been proposed many methods. One of conventional methods to seal around a hole is to form a bead around a hole. As shown in Fig. 2, for example, a gasket 20 comprises an upper plate 21, a lower plate 23, and a middle plate 22 having a bead 22a around a cylinder hole Hc. In the gasket 20, the bead 22a only provides a sealing pressure around the cylinder hole Hc. Therefore, fluid passing through the hole Hc may permeate through the plates. The sealing ability of the gasket 20 is not good. In view of the prior art, a gasket 25 as shown in Fig. 3 has been proposed in Serial No. 193,215 filed on May 11, 1988. The gasket 25 comprises an upper plate 26 with a curved portion 26a and a flange 26b, and a lower plate 27. The gasket 25 can securely seal around the hole Hc. However, since an area around the hole Hc is only sealed by the curved portion 26a, the sealing area that forms sealing pressure is relatively narrow. Further, since the curved portion may strongly abut against the engine blocks, in case the engine blocks are formed of aluminum alloy, the engine blocks may deform at the curved portion. Therefore, a gasket with relatively wide sealing area without affecting the engine blocks has been desired. Furthermore, a steel laminate gasket of the type mentioned in the beginning is known from US-A-4 807 892. This gasket is formed of a first plate with a first bead, and a second plate with a second bead. The first bead is larger than the second bead and does not laminate the second plate. Therefore, surface pressure formed by the first and second beads cannot be easily regulated. One object of the present invention is to provide a steel laminate gasket, which can provide wide and high sealing pressure around a hole to be sealed. Another object of the present invention is to provide a steel laminate gasket as stated above, which does not cause any damage to portions abutting against the gasket. A further object of the present invention is to provide a steel laminate gasket as stated above, which can easily and economically manufactured. Further objects and advantages of the invention will be apparent from the following descriPtion of the invention. In accordance with the invention there is provided a steel laminate gasket of the type mentioned in the beginning, which is characterized in that at least one side wall is formed on one of the base portion and the flange spaced from the curved portion to surround the first hole so that the distance between the flange and the base portion laterally inside the side wall is greater than the distance between the flange and base portion laterally outside the side wall, and at least one first bead is situated between the side wall and the curved portion to extend toward the other of the base portion and the flange. In a preferred embodiment of the invention an area aound the first hole surrounded by the side wall and the curved portion forms an embossed portion with the first bead. When the gasket is tightened, the embossed portion forms a plurality of corrugated beads to seal around the first hole. Since the embossed portion is provided with the first bead, a strong sealing pressure is formed especially at the first bead. Namely, the gasket of the invention can provide a moderate sealing pressure at the embossed portion and a strong sealing pressure at the first bead. Therefore, an area around the hole can be sealed properly. Brief Description of the Drawings Fig. 1 is a partial plan view of a conventional steel laminate gasket; Fig. 2 is an enlarged section view taken along line 2-2 in Fig. 1; Fig. 3 is a section view, similar to Fig. 2, for showing a related invention; Fig. 4 is a perspective section view of a part of a first embodiment of a steel laminate gasket of the present invention; Figs. 5-7 are perspective section views, similar to Fig. 4, for showing second to fourth embodiments of the gasket of the invention; and Fig. 8 is a section view of a part of a fifth embodiment of a steel laminate gasket of the invention. Detailed Description of Preferred Embodiments Referring to Fig. 4, a first embodiment A of a steel laminate gasket of the present invention is shown. The gasket A as shown in Fig. 4 is a cylinder head gasket, similar to Fig. 1, and is provided with a plurality of holes, i.e. cylinder holes Hc, water holes Hw, oil holes Ho and bolt holes Hb. Areas around the cylinder holes Hc are sealed in accordance with the present invention. However, if required, areas around the water holes Hw, oil holes Ho and bolt holes Hb may be sealed as well. The gasket A comprises an upper plate A30, and a lower plate A31 situated under the upper plate A30. The upper plate A30 is provided with a base portion A30a extending substantially throughout the entire area of the gasket, a diagonal side wall A30b extending diagonally and upwardly from the base portion A30a around the cylinder hole Hc, and an embossed portion A30c with a bead A30d extending downwardly therefrom. The upper plate A30 also includes a curved portion A30e around the cylinder hole Hc, and a flange A30f situated under the embossed portion A30c. The flange A30f is spaced apart from the embossed portion A30c, but an end portion of the flange A30f is located under the base portion A30a. The bead A30d contacts the flange A30f. The lower plate A31 is a flat plate situated under the base portion A30a of the upper plate A30 and is thinner than the upper plate A30. The lower plate A31 is provided with a hole A32. The diameter of the hole A32 is larger than the outer diameter of the flange A30f. When the gasket A is assembled, the lower plate A31 is situated under the upper plate A30 so that the flange A30f is located in the hole A32. The lower plate A31 does not pile on the flange A30f. When the gasket A is situated between a cylinder head and a cylinder block (both not shown) and is tightened, the embossed portion A30c and the bead A30d are compressed. As a result, a plurality of corrugated beads are formed on the embossed portion A30c and the bead A30d. The corrugated beads on the bead A30d provide a sealing pressure stronger than those on the embossed portion A30c. Accordingly, when the gasket A is tightened, a strong sealing pressure formed by the bead A30d is formed in a wide sealing area formed by the embossed portion A30c. A part of the sealing area is only strongly sealed. Therefore, an area around the cylinder hole Hc can be securely sealed. Also, the cylinder head is not damaged by the corrugated beads. Fig. 5 shows a second embodiment B of a steel laminate gasket of the present invention. The gasket B comprises an upper plate B30 with a side wall B30b, embossed portion B30c, bead B30d, curved portion B30e and flange B30f, and a plate B31, similar to the gasket A. However, the gasket B further includes a plate B33 having a main portion B33a situated under the plate B31, a bead B33b situated under the embossed portion B30c between the side wall B30b and the bead B30d, and an end portion B33c situated under the bead B30d. In the gasket B, the bead B33b is situated under the embossed portion B30c in addition to the bead B30d. Accordingly, when the gasket B is tightened, a strong sealing pressure is formed by the beads B30d, B33b. Since the beads B30d, B33b are spaced apart from each other, the sealing pressure does not concentrate at one portion. Therefore, a strong force to deform a cylinder head is not formed. An area around the cylinder hole Hc is strongly and effectively sealed. Fig. 6 shows a third embodiment C of a steel laminate gasket of the invention. The gasket C comprises an upper plate C30 with an embossed portion C30c and a bead C30d, a plate C33 with a bead C33b, and a plate C31, similar to the gasket B. The gasket C is different from the gasket B in that the plate C31 is located under the plate C33 though the plate B31 is situated between the plates B33 and B30. The gasket C operates as in the gasket B. Fig. 7 shows a fourth embodiment D of a steel laminate gasket of the invention. The gasket D comprises an upper plate D30 with an embossed portion D30c and a bead D30d, a plate D33 with a bead D33b and an end portion D33c, and a plate D31, similar to the gasket B. The gasket D is different from the gasket B in that the end portion D33c of the plate D33 does not extend close to the cylinder hole Hc beyond the bead D30d, though in the gasket B, the end portion B33c is located under the bead B30d. In the gasket D, the end portion D33c of the plate D33 does not extend close to the cylinder hole Hc, so that although the upper plate D30 is exposed to high temperature at a portion adjacent the cylinder hole Hc, the plate D33 is not exposed to high temperature as in the plate D30. Accordingly, the upper plate D30 must be made of a material having high heat resistant property, but the lower plate D33 may be made of a material less heat resistant property than the upper plate D30. Further, since the plate D33 is not exposed to high temperature, the creep relaxation of the plate D33 is substantially prevented. Fig. 8 shows a fifth embodiment E of a steel laminate gasket of the invention. The gasket E comprises an upper plate E30 with a hole E32, and a lower plate E31 situated under the upper plate E30. The lower plate E31 is provided with a curved portion E31e, and a flange E31f wherein a diagonal side wall E31b, embossed portion E31c and a bead E31d are formed. Namely, while the gasket A is provided with the embossed portion A30c on the base portion A30a, in the gasket E, the embossed portion E31c is formed on the flange E31f. The gasket E operates as in the gasket A. In the present invention, the gasket is provided with a first plate having a relatively wide embossed portion with a bead around a hole to be sealed, and a second plate situated at a flange side of the first plate. When the gasket is tightened, the embossed portion and the bead are compressed to form a plurality of corrugated beads. The corrugated beads at the bead form a sealing pressure stronger than those at the embossed portion. Therefore, an area around the cylinder hole is sealed by moderate sealing pressure formed by the corrugated beads at the embossed portion and high sealing pressure formed by the corrugated beads at the bead.

Claims: A steel laminate gasket (A to E) for an internal combustion engine having at least one hole therein, said gasket (A to E) comprising a first plate (A30, B30, C30, D30, E31) having a first hole (Hc) corresponding to the hole of the engine and a base portion (A30a), said first plate (A30, B30, C30, D30, E31) including at least one curved portion (A30e, B30e, E31e) integrally formed with the base portion (A30a) to extend transversely thereto to define the first hole (Hc), at least one flange (A30f, B30f, E31f) integrally formed with the curved portion (A30e, B30e, E31e) and being located at a side of the base portion (A30a) to extend substantially parallel to the base portion (A30a), a second plate (A31, B31, C31, D31, E30) situated adjacent to and at a flange side of the first plate (A30, B30, C30, D30, E31), and having a second hole (A32, E32) with a diameter larger than the outer diameter of the flange (A30f, B30f, E31f) to allow the flange (A30f, B30f, E31f) to be located inside the second hole (A32, E32) when the first (A30, B30, C30, D30, E31) and second (A31, B31, C31, D31, E30) plates are assembled characterized in that at least one side wall (A30b, B30b, E31b) is formed on one of the base portion (A30a) and the flange (A30f, B30f, E31f) spaced from the curved portion (A30e, B30e, E31e) to surround the first hole (Hc) so that the distance between the flange (A30f, B30f, E31f) and base portion (A30a) laterally inside the side wall (A30b, B30b, E31b) is greater than the distance between the flange (A30f, B30f, E31f) and base portion (A30a) laterally outside the side wall (A30b, B30b, E31b), and at least one first bead (A30d, B30d, C30d, D30d, E31d) is situated between the side wall (A30b, B30b, E31b) and the curved portion (A30e, B30e, E31e) to extend toward the other of the base portion (A30a) and the flange (A30f, B30f, E31f). A steel laminate gasket (A to E) according to claim 1, characterized in that an area around the first hole (Hc) surrounded by the side wall (A30b, B30b, E31b) and the curved portion (A30e, B30e, E31e) forms an embossed portion (A30c, B30c, C30c, D30c, E31c) with the first bead (A30d, B30d, C30d, D30d, E31d), said embossed portion (A30c, B30c, C30c, D30c, E31c) forming a plurality of corrugated beads to seal around the first hole (Hc) when the gasket (A to E) is tightened. A steel laminate gasket (A to E) according to claim 2, characterized in that the width of the embossed portion (A30c, B30c, C30c, D30c, E31c) is shorter than that of the flange (A30f, B30f, E31f) so that the outer periphery of the flange (A30f, B30f, E31f) touches the base portion (A30a). A steel laminate gasket (A to D) according to claim 3, characterized in that the embossed portion (A30c, B30c, C30c, D30c) is formed on the base portion (A30a). A steel laminate gasket (B to D) according to claim 4, characterized by comprising a third plate (B33, C33, D33) having a third hole greater than the first hole (Hc), a second bead (B33b, C33b, D33b) situated around the third hole, said second bead (B33b, C33b, D33b) being situated between the flange (B30f) and the embossed portion (B30c, C30c, D30c) to extend toward the embossed portion (B30c, C30c, D30c) between the side wall (B30b) and the first bead (B30d, C30d, D30d), and a main area situated outside the second bead (B33b, C33b, D33b). A steel laminate gasket (B, D) according to claim 5, characterized in that said main area of the third plate (B33, D33) is located outside the second plate (B31, D31). A steel laminate gasket (D) according to claim 6, characterized in that a peripheral portion (D33c) of the third plate (D33) around the third hole is located outside the first bead (D30d) relative to the first hole (Hc). A steel laminate gasket (C) according to claim 5, characterized in that said main area of the third plate (C33) is located between the first (C30) and second (C31) plates. A steel laminate gasket (E) according to claim 3, characterized in that the embossed portion (E31c) is formed on the flange (E31f).

Inventors: INAMURA, SUSUMU, UDAGAWA, TSUNEKAZU
Applicants: ISHIKAWA GASKET CO. LTD.
Application year: 1990
Main classification: F02F11
IPC codes: F16J15, F02F11