Metal laminate gasket with a plate connecting device

Abstract: A metal laminate gasket (A) of the invention is used for an internal combustion engine. The gasket is basically formed of first (A10) and second (A11) metal plates piled together, and includes a cylindrical portion integrally formed on the first metal plate (A10) with a first hole, and a second hole formed in the second plate. The cylindrical portion (A10a) extends substantially perpendicularly to the first plate (A10), and has an axial length along the inner periphery at least equal to the thickness of the gasket (A). The second hole (A11b) has a diameter greater than an outer diameter of the cylindrical portion (A10a). When the gasket (A) is assembled, after the cylindrical portion (A10a) is inserted into the second hole (A11b), the cylindrical portion (A10a) is enlarged to press fit against the inner periphery of the second hole (A11b). Thus, the first and second metal plates (A10,A11) are firmly connected together without portions extending outwardly from outer surfaces of the gasket (A).

Description: Background of the Invention and Related Art Statement The present invention relates to a metal laminate gasket with a plate connecting device, which connects metal plates for constituting the metal laminate gasket. A metal laminate gasket is formed of a plurality of metal plates laminated together. Thus, after the metal plates are laminated, the laminated plates are connected to prevent disassembly of the gasket. In case a gasket includes a grommet or a turned portion, the gasket may be connected together by the grommet or the turned portion without using a connecting device. However, if the gasket does not have the grommet or the turned portion, the metal plates are connected together by the connecting device. In one connecting device, a lower plate may be provided with flaps, which are turned over an upper plate to connect the upper and lower plates together. In this case, at least four flaps are required to properly connect the plates together. Also, if one or more middle plates are installed between the upper and lower plates, the middle plate may not be securely retained between the upper and lower plates. In order to solve the above problems, the plates may be connected together by spot welding. Alternatively, laminated plates may be integrally dented, wherein the bottom portions of the dent are enlarged to firmly connect the plates together [Japanese Utility Model Publication (KOKAI) 4-28272]. However, in case an outer plate is covered with a coating, or a gasket includes metal plates which are not suitable for pressing or welding, forming of dents or welding is not appropriate for connecting the plates together. Further, in case the welding or dents are used for connecting the plates, it is required to establish portions for the welding or dents in the gasket so that the sealing ability of the gasket is not affected by the welding or dents. In this case, also, some restrictions may be imposed in forming the holes for the cylinder bores, water, oil and so on. As a result, assembly or processing cost of the gasket may rise. JP-A-63 119 935 describes a method of joining of two metal plates, for applications other than gaskets, by the swaging of a cylindrical pressing on one plate into a chamfered recess on the other plate. EP-A-0 338 537, on which the preamble of claim 1 is based, describes the location together of orifi of two or more metal plates in a gasket by providing a cylindrical portion on one plate which locates in corresponding holes of the other plates. However, the plates are not immovably joined together by the cylindrical portion. The present invention has been made to obviate the above problems in the conventional techniques. One object of the invention is to provide a metal laminate gasket, wherein metal plates can be easily and securely connected together without using specific spaces for connecting the plates. Another object of the invention is to provide a metal laminate gasket as stated above, which can provide surface pressure around a connecting portion. A further object of the invention is to provide a metal laminate gasket as stated above, wherein the plates are securely connected together even if the gasket includes a coating or a plate unsuitable for pressing. A still further object of the invention is to provide a metal laminate gasket as stated above, which can be easily and economically manufactured. Further objects and advantages of the invention will be apparent from the following description of the invention. Summary of the Invention In the present invention, a metal laminate gasket is primarily used for an internal combustion engine. The gasket may be a cylinder head gasket or a manifold gasket. A metal laminate gasket for an internal combustion engine, comprising: first and second metal plates extending substantially throughout an entire area of the engine, said metal plates being piled together for constituting the metal laminate gasket, a cylindrical portion integrally formed on the first metal plate and extending substantially perpendicularly to the first metal plate, said cylindrical portion having an inner periphery to form a first hole therein and an axial length along the inner periphery at least equal to the thickness of the gasket, and a second hole formed in the second metal plate, said second hole having an inner periphery and a diameter greater than an outer diameter of the cylindrical portion, said cylindrical portion being inserted into the second hole, characterised in that said cylindrical portion of said first plate further includes a thickened portion formed at a forward end to project radially inwardly of the cylindrical portion, in that, after its insertion in the second hole of the second plate, said cylindrical portion is enlarged radially outwardly to press fit against the inner periphery of the second hole so that the first and second metal plates are firmly connected together without portions extending outwardly from outer surfaces of the gasket, and in that said thickened portion is pressed radially outwardly against the cylindrical portion at a time of enlarging the diameter of the cylindrical portion so as to become a part of a flange formed at the forward end of said portion. In case the gasket is a cylinder head gasket, the gasket includes cylinder bores, water holes, oil holes and bolt holes. The first hole may be used as one of the water holes, oil holes and bolt holes. Thus, the first hole is fully utilised as a part necessary to the gasket, which means that it is unnecessary to establish a specific space for a gasket connecting device. In the invention, the cylindrical portion extends perpendicularly to the first plate, and has the axial length equal to or slightly greater than the thickness of the gasket. Thus, when the gasket is tightened, the cylindrical portion is compressed to provide surface pressure thereat, which seals around the first hole. Also, in the invention, the first plate is only processed, and is required to have elastic property. Thus, the second plate may be made of a material which is not suitable for pressing. The cylindrical portion includes a thickened portion formed at a forward end and projecting inwardly of the cylindrical portion. The thickened portion is a part of a flange formed at the forward end and is formed by pushing the flange inwardly of the cylindrical portion at a time of enlarging the diameter of the cylindrical portion. Also, in the invention, one or more third plates may be situated between the first and second plates. In this case, the cylindrical portion may immovably engage the second plate by press fitting without substantially press fitting the third plate. Brief Description of the Drawings Fig. 1 is a plan view of a first embodiment of a cylinder head gasket of the invention; Fig. 2 is an enlarged section view taken along a line 2-2 in Fig. 1; Fig. 3 is an explanatory section view for showing that the first embodiment of the invention is formed; and Fig. 4 is a section view, similar to Fig. 2, for showing a second embodiment of the gasket of the invention. Detailed Description of Preferred Embodiments Referring to Figs. 1 and 2, a first embodiment A of a metal laminate gasket of the invention is shown. The gasket A is a cylinder head gasket and includes a plurality of cylinder bores Hc, water holes Hw, oil holes Ho and bolt holes Hb, as in the conventional gasket. The gasket A is formed of an upper plate A10, and a lower plate A11, which extend substantially throughout an entire area of an engine to be sealed. The lower plate A11 includes flaps A11a at a peripheral edge and is turned over the upper plate A10 to connect the upper and lower plate A10, A11 together at the longitudinal ends of the gasket A. In the present invention, the upper and lower plates A10, A11 are also connected together at the bolt hole Hb1 by a connecting mechanism of the invention. Since the subject matter of the invention resides in the connecting mechanism, sealing mechanisms for the cylinder bores, water holes and the oil holes are omitted. Any sealing mechanisms may be used in the invention. As shown in Fig. 2, the lower plate A11 includes a hole A11b, while the upper plate A10 includes a cylindrical portion A10a and a flange A10b. In the gasket A, the cylindrical portion A10a is located inside the hole A11b, and the flange A10b is urged against the inner periphery of the cylindrical portion A10a to press fit the cylindrical portion A10a to the inner periphery of the hole A11b. Since the cylindrical portion A10a is press fitted to the hole A11b, the upper and lower plates A10, A11 are firmly connected together. The gasket A is not accidentally disassembled when installing to the engine. As shown in Fig. 3, when the gasket A is prepared, the plate A10 is formed such that the cylindrical portion A10a extends perpendicularly to the plate A10, and the flange A10b projects inwardly from the cylindrical portion A10a. The diameter of the hole A11b is made slightly larger than the outer diameter of the cylindrical portion A10a. Thus, the cylindrical portion A10a can be easily inserted into the hole A11b. After the cylindrical portion A10a is inserted into the hole A11b of the lower plate A11, a support member 15 is placed above the upper plate A10, and a press member 16 with a tapered end is urged into the flange A10b. Thus, the flange A10b is pushed upwardly to contact the inner periphery of the cylindrical portion A10a, and the cylindrical portion A10a is slightly enlarged and press fitted to the inner periphery of the hole A11b. As a result, the plates A10, A11 are firmly joined together. In the invention, since the flange A10b is pushed inwardly of the cylindrical portion A10a, the cylindrical portion A10a is strongly engaged with the hole A11b of the lower plate A11. Also, the strength of the cylindrical portion A10a is enhanced. After the flange A10b is urged against the cylindrical portion A10a, a part of the flange A10b still remains inside the hole Hb1. However, the part of the flange A10b does not interfere with a bolt to be inserted into the bolt hole Hb1. If necessary, the flange is made small, so that when the flange is urged against the cylindrical portion A10a, a substantially flat inner surface is formed inside the cylindrical portion A10a. When the gasket A is installed in a cylinder head and a cylinder block and is tightened, the cylindrical portion A10a provides surface pressure thereat, because although the laminated portion of the two plates is slightly compressed, the cylindrical portion A10a is not substantially compressed. Thus, the cylindrical portion A10a provides sealing function, as well. Accordingly, if a sealing function is required around a water hole or an oil hole, the connecting mechanism of the invention may be employed. Fig. 4 shows a second embodiment B of the gasket of the invention. The gasket B includes an upper plate B10 having a cylindrical portion B10a and a flange B10b, and a lower plate B11 having a hole B11b, similar to the gasket A. In the gasket B, however, a middle plate B12 having a hole B12a is situated between the upper and lower plates B10, B11. In the gasket B, the middle plate B12 is sandwiched between the upper and lower plates B10, B11. Thus, when the cylindrical portion B10a is press fitted, the cylindrical portion B10a need not engage the hole B12a and may engage only the hole B11b. The gasket B operates as in the gasket A. In the gasket of the invention, the connecting mechanism can be formed around an existing hole, such as water hole, oil hole and bolt hole. Thus, the space of the gasket is sufficiently utilized. The specific space for the connecting mechanism is not required. If required, however, the connecting mechanism may be independently formed in addition to the existing holes. In the present invention, if the plate with the cylindrical portion is made of a compressible material having elasticity, other plate need not have such property. Further, even if the outer plate has a coating, it is possible to easily and securely connect the plates together. The connecting mechanism of the invention may be used for various kinds of the gaskets. While the invention has been explained with reference to the specific embodiments of the invention, the explanation is illustrative, and the invention is limited only by the appended claims.

Claims: A metal laminate gasket (A) for an internal combustion engine, comprising: first (A10) and second (A11) metal plates extending substantially throughout an entire area of the engine, said metal plates being piled together for constituting the metal laminate gasket (A), a cylindrical portion (A10a) integrally formed on the first metal plate (A10) and extending substantially perpendicularly to the first metal plate, said cylindrical portion (A10a) having an inner periphery to form a first hole therein and an axial length along the inner periphery at least equal to the thickness of the gasket (A), and a second hole (A11b) formed in the second metal plate (A11), said second hole having an inner periphery and a diameter greater than an outer diameter of the cylindrical portion (A10a), said cylindrical portion being inserted into the second hole (A11b), characterised in that said cylindrical portion of said first plate further includes a thickened portion (A10b) formed at a forward end to project radially inwardly of the cylindrical portion, in that, after its insertion in the second hole (A11b) of the second plate (A11), said cylindrical portion is enlarged radially outwardly to press fit against the inner periphery of the second hole so that the first and second metal plates are firmly connected together without portions extending outwardly from outer surfaces of the gasket, and in that said thickened portion (A10b) is pressed radially outwardly against the cylindrical portion at a time of enlarging the diameter of the cylindrical portion so as to become a part of a flange formed at the forward end of said portion. A metal laminate gasket (B) according to claim 1, further comprising a least one third plate (B12) situated between the first (B10) and second (B11) plates, said cylindrical portion (B10a) immovably engaging the second plate (B11) by press fitting without substantially press fitting to the third plate (B12). A metal laminate gasket according to claim 1 or claim 2, wherein said cylindrical portion (A10a; B10a) provides surface pressure when the gasket is tightened to thereby seal around the first hole. A metal laminate gasket according to any one preceding claim, wherein said gasket (A; B) includes a cylinder bore (Hc), a water hole (HW), and oil hole (Ho) and bolt holes (Hb), said first hole constituting at least one of the water hole, oil hole and bolt holes. A metal laminate gasket according to any one preceding claim wherein said second plate (A11; B11) is made of a material which is not suitable for pressing.

Inventors: MIYAOH YOSHIO, MIYAOH, YOSHIO, Miyaoh, Yoshio, c/o Ishikawa Gasket Co. Limited
Applicants: ISHIKAWA GASKET, ISHIKAWA GASKET CO. LTD.
Application year: 1993
Main classification: F16J1
IPC codes: F16J15