WO2009005179A1

WO2009005179A1 - Gasket for preventing pinch

Info

Publication number: WO2009005179A1
Application number: PCT/KR2007/003551
Authority: WO
Inventors: Jong Sun Lee; Tae Yong Seo
Original assignee: DONGAH MANUFACTURING CORP
Current assignee: DONGAH MANUFACTURING CORP
Priority date: 2007-07-03
Filing date: 2007-07-24
Publication date: 2009-01-08
Anticipated expiration: 2010-01-03
Also published as: CN101849123A; KR100935388B1; KR20090003609A

Abstract

A stack-type gasket includes a plurality of plates which are coupled by means of caulkings, and jam-preventing protrusions are formed on the caulkings of at least one of the plates. Therefore, since the jam-preventing protrusions are formed on at least one of the plurality of plates, it is possible to prevent stack-type gaskets from becoming jammed or wedged with each other. As a consequence, assembly work can be easily conducted, and it is possible to prevent two or more stack-type gaskets from being interposed between the junction surfaces of a cylinder head and a cylinder block.

Description

[DESCRIPTION]

[invention Title]

GASKET FOR PREVENTING PINCH [Technical Field] The present invention relates to a jam-preventing stack- type gasket, and more particularly, to a jam-preventing stack- type gasket which is formed by coupling a plurality of plates using caulkings and in which jam-preventing protrusions are formed on at least one of the plurality of plates to prevent stack-type gaskets from being jammed with each other. [Background Art]

As is well known in the art, in engines (internal combustion engines), hydraulic and pneumatic apparatuses, etc., gaskets are fitted between the coupling surfaces or the contact surfaces of parts through which liquid or gas flows, so as to maintain airtightness and prevent leakage of the liquid or gas.

For example, in the engine of a motor vehicle, gaskets are installed between the junction surfaces of a cylinder block and a cylinder head and between the contact surfaces of the cylinder head and a cylinder head, to serve as sealing means and prevent the leakage of high pressure combustion gas present in a combustion chamber. The inside of the combustion chamber is subjected to extreme conditions, in which the internal pressure of a cylinder continuously varies during a four stroke cycle which is composed of intake, compression, explosion and exhaust .

In particular, since the internal gas pressure during the explosion stroke increases to a level that exceeds the locking force of bolts for locking the cylinder head to the cylinder block, force that tends to lift up the cylinder head is generated, and a fine gap is produced between the gasket and the cylinder head or the cylinder block. For example, in a compression igniting engine, when the lift force acts on the cylinder head, since the cylinder head is lifted from the upper surface of the cylinder block by 10μm(0.01mm) ~15um(0.015mm) , a variable gap is created between the cylinder head and the cylinder block. At this time, because the internal gas pressure approaches 200 times of the atmospheric pressure, the internal gas leaks to the outside through the gap, and an adverse influence is exerted on the combustion efficiency of the internal combustion engine . The fine gap continuously varies depending upon the change of the load in the cylinder while the cycle proceeds. Therefore, in order to ensure satisfactory sealing of the internal combustion engine and prevent the fine gap from being created in the explosion stroke, a stack-type gasket having elasticity as well as durability is needed.

In general, a stack-type gasket has been used by coupling a plurality of thin metal plates.

In an example, the stack-type gasket can be constructed from two plates. The two plates includes a bead plate, which is formed with a bead to allow the junction surfaces of the cylinder head and the cylinder block to be sealed by the elastic force of the bead, and a stopper plate, which prevents the sealing performance of the gasket from being degraded due to complete squeezing of the bead of the bead plate.

The methods for coupling two plates are basically divided into a grommet type, a hemming type and a YAG type. The two plates are usually coupled with each other against detachment by riveting, YAG welding, etc.

However, in the case where the plates are coupled with each other by riveting, annoyance is caused, since a riveting operation must be separately conducted. In the case of YAG welding, thermal stress is induced in the assembled plates due to the heat generated by the welding, and thermal deformation occurs in the assembled stack-type gasket due to the thermal stress. Moreover, annoyance is caused, since a separate welding operation must be conducted.

In order to respond to these problems, a caulking method is used, in which plates are coupled with each other by means of caulkings. In this caulking method, counter-shaped caulkings are formed on the respective plates, and the plates are coupled with each other in a manner such that the counter- shaped caulkings are fitted with each other without the need to separately conduct riveting or welding.

Nevertheless, in the caulking method, when a number of stack-type gaskets are piled one upon another so that the stack-type gaskets can be used one by one as needed, since the caulkings of the stack-type gaskets G, G' and G" are inserted into and become coupled with each other, as shown in FIG. 1, it is not easy to separate the coupled stack-type gaskets, and in the worst case, two stack-type gaskets are likely to be erroneously interposed between the cylinder block and the cylinder head. [Disclosure! [Technical Problem]

Accordingly, the present invention has been made in an effort to solve the problems occurring in the related art, and an object of the present invention is to provide a jam- preventing stack-type gasket which is formed by coupling a plurality of plates using caulkings and in which jam-preventing protrusions are formed on at least one of the plurality of plates separately from the caulkings in order to prevent stack- type gaskets from becoming jammed with each other. [Technical Solution]

In order to achieve the above object, according to one aspect of the present invention, there is provided a stack-type gasket including a plurality of plates which are coupled by means of caulkings, wherein jam-preventing protrusions are formed on the caulkings of at least one of the plates.

Meanwhile, in the present invention, when forming the jam- preventing protrusions on the plurality of plates constituting the stack-type gasket, the jam-preventing protrusions are formed on the uppermost plate among the plurality of plates. The forming position can be determined such that the jam- preventing protrusions are formed in valley portions of the caulkings to project in a direction opposite to ridge portions of the caulkings.

Also, in the present invention, the jam-preventing protrusions are formed on the lowermost plate among the plurality of plates. The forming position can be determined such that the jam-preventing protrusions are formed on ridge portions of the caulkings to project in the same direction as the ridge portions of the caulkings.

Further, in the present invention, the jam-preventing protrusions are formed on all of the plates constituting the stack-type gasket. The respective jam-preventing protrusions can be formed on valley portions of the caulkings of the plates such that they extend in a direction opposite to ridge portions of the caulkings and are fitted to and locked with each other. Moreover, in the present invention, the jam-preventing protrusions are formed on all of the plates constituting the stack-type gasket. The respective jam-preventing protrusions can be formed on ridge portions of the caulkings of the plates such that they extend in the same direction as the ridge portions of the caulkings and are fitted and locked with each other.

Furthermore, in the present invention, the jam-preventing protrusions can be formed on ridge portions and valley portions of the caulkings of the respective outermost plates in the plurality of plates constituting the stack-type gasket in such a way as to extend in the same direction as and in a direction opposite to the ridge portions of the caulkings, respectively, such that valley portions of the jam-preventing protrusions face each other. [Advantageous Effects]

In the jam-preventing stack-type gasket according to the present invention, since jam-preventing protrusions are formed on at least one of a plurality of plates, it is possible to prevent stack-type gaskets from being jammed or wedged with each other. As a consequence, assembly work can be easily conducted, and it is possible to prevent two or more stack-type gaskets from being interposed between the junction surfaces of a cylinder head and a cylinder block. [Description of Drawings]

FIG. 1 is a cross-sectional view illustrating a state in which conventional stack-type gaskets are placed on one another; FIG. 2 is a plan view illustrating the stopper plate of a jam-preventing stack-type gasket in accordance with a first embodiment of the present invention;

FIG. 3 is a cross-sectional view illustrating the W part of FIG. 2; FIG. 4 is a plan view illustrating the bead plate of the jam-preventing stack-type gasket in accordance with the first embodiment of the present invention;

FIG. 5 is a cross-sectional view illustrating the ^ΛB' part of FIG. 4; FIG. 6 is a perspective view illustrating the state in which the ^ΛA' part, shown in FIG. 3, and the ^ΛB' part, shown in FIG. 5, are coupled with each other in accordance with the first embodiment of the present invention;

FIG. 7 is a perspective view illustrating the state in which the ^ΛA' part, shown in FIG. 3, and the ^λB' part, shown in FIG. 5, are coupled with each other in accordance with a second embodiment of the present invention;

FIG. 8 is a perspective view illustrating the state in which the ^λA' part, shown in FIG. 3, and the ^ΛB' part, shown in FIG. 5, are coupled with each other in accordance with a third embodiment of the present invention;

FIG. 9 is a perspective view illustrating the state in which the ^yA' part, shown in FIG. 3, and the "B' part, shown in FIG. 5, are coupled with each other in accordance with a fourth embodiment of the present invention;

FIG. 10 is a perspective view illustrating the state in which the ^λA' part, shown in FIG. 3, and the ^λB' part, shown in FIG. 5, are coupled with each other in accordance with a fifth embodiment of the present invention; and

FIG. 11 is a cross-sectional view illustrating the state in which the stack-type gaskets in accordance with the first embodiment of the present invention, shown in FIGs. 2 through 6, are placed on one another.

[Best Mode]

Hereinafter, a jam-preventing stack-type gasket in accordance with preferred embodiments of the present invention will be described in detail with reference to the attached drawings .

In the drawings, FIG. 1 is a cross-sectional view illustrating the state in which conventional stack-type gaskets are placed on one another, FIG. 2 is a plan view illustrating the stopper plate of a jam-preventing stack-type gasket in accordance with a first embodiment of the present invention, FIG. 3 is a cross-sectional view illustrating the ^λA' part of FIG. 2, FIG. 4 is a plan view illustrating the bead plate of the jam-preventing stack-type gasket in accordance with the first embodiment of the present invention, FIG. 5 is a cross- sectional view illustrating the ^ΛB' part of FIG. 4, FIG. 6 is a perspective view illustrating the state in which the W part, shown in FIG. 3, and the ^ΛB' part, shown in FIG. 5, are coupled with each other in accordance with the first embodiment of the present invention, FIG. 7 is a perspective view illustrating the state in which the W part, shown in FIG. 3, and the ^λB' part, shown in FIG. 5, are coupled with each other in accordance with a second embodiment of the present invention, FIG. 8 is a perspective view illustrating the state in which the 'A' part, shown in FIG. 3, and the ^λB' part, shown in FIG.

5, are coupled with each other in accordance with a third embodiment of the present invention, FIG. 9 is a perspective view illustrating the state in which the W part, shown in FIG. 3, and the ^λB' part, shown in FIG. 5, are coupled with each other in accordance with a fourth embodiment of the present invention, FIG. 10 is a perspective view illustrating the state in which the ^λA' part, shown in FIG. 3, and the ^ΛB' part, shown in FIG. 5, are coupled with each other in accordance with a fifth embodiment of the present invention, and FIG. 11 is a cross-sectional view illustrating the state in which the stack-type gaskets in accordance with the first embodiment of the present invention, shown in FIGs. 2 through

6, are placed on one another. In a stack-type gasket, which is made from a plurality of plates, a plurality of caulkings is formed on at least one of the plates to couple the plates with each other. In the present invention, in order to prevent stack-type gaskets from being jammed with each other due to the presence of the caulkings, at least one protrusion is formed in each caulking portion, so that the stack-type gaskets are prevented from being jammed with each other. Therefore, the present invention has been made to prevent stack-type gaskets from being jammed with (from sticking to?) each other by forming protrusions in each caulking portion when each stack-type gasket is made from a plurality of plates. Hereinbelow, the case in which a stack-type gasket is composed of a bead plate and a stopper plate will be explained with reference to FIGs. 2 through 11, representing the stack-type gasket which is made from a plurality of plates.

Referring to FIG. 2, in a stopper plate 21, depending upon the number of cylinders of an internal combustion engine, a corresponding number of bores 28 (the illustrated example applies to a four-cylinder engine) are defined through the middle portion of a flat part 22. Cooling water supply holes 29 for cooling the cylinders and oil supply holes 27 for supplying lubricant are defined around the bores 28, that is, between the bores 28 and the edges of the stopper plate 21. Also, a plurality of caulkings 26 for coupling the stopper plate 21 with a bead plate 1, which will be described later, is formed on the stopper plate 21. The caulkings 26 protrude from the flat part 22 to have the sectional shape of a trapezoid, which defines a flat surface on a distal end thereof, or a semi-circle. While the caulking 26 as a whole can be formed by pressing, in the present invention, for example, the caulking 26 can be formed in a manner such that a pair of parallel cut lines C is formed through the plate and the portion of the plate existing between the cut lines C is pressed. Due to the fact that the ridge portion ^λa' of the caulking 26 is inserted into the valley portion ^λb' of the caulking 6 of the bead plate 1, which will be described below, as can be seen from FIGs. 6 through 11, the stopper plate 21 and the bead plate 1, placed thereunder, are coupled with each other.

Bolt insertion holes 30 are defined through the stopper plate 21 adjacent to the edges of the stopper plate 21 so that bolts for locking a cylinder block (not shown) and a cylinder head (not shown) to each other can pass through the bolt insertion holes 30.

In the bead plate 1, which is placed under the stopper plate 21, as shown in FIG. 4, in order to correspond to the respective component elements of the stopper plates 21, a flat part 2, bores 8, cooling water supply holes 9, oil supply holes 7, and bolt insertion holes 10 are defined at the same positions and have the same shapes.

The bead plate 1 is differentiated from the stopper plate 21 in that bore beads 3 for preventing the leakage of combustion gas by virtue of the elasticity thereof are formed around the bores 8, oil beads 4 for preventing the leakage of high pressure oil are formed around the oil supply holes 7, and an edge bead 5 for preventing combustion gas, oil and cooling water from leaking from the junction area between the cylinder block and the cylinder head is formed a predetermined distance from the edges of the bead plate 1.

Caulkings 6 are formed on the bead plate 1 at positions corresponding to the caulkings 26 of the stopper plate 21 to have the same shape as the caulkings 26 of the stopper plate 21. As the caulkings 6 are formed in this way, as shown in FIGs. 6 through 11, the ridge portions ^Λa' of the caulkings 26 formed on the stopper plate 21 can be inserted into the valley portions ^λb' of the caulkings 6 formed on the bead plate 1, as a result of which the bead plate 1 is coupled to the lower surface of the stopper plate 21.

The characterizing feature of the present invention resides in that jam-preventing protrusions 40 are formed on the caulkings 6 formed on the bead plate 1 and/or the caulkings 26 formed on the stopper plate 21 in such a way as to extend in a direction which is the same as or opposite to that of respective caulkings 6 and 26, so that stack-type gaskets are prevented from being jammed with each other.

The jam-preventing protrusions 40 can be formed to have various sectional shapes, such as a semicircle and a trapezoid. Due to the projecting shape of the jam-preventing protrusions 40, as can be readily seen from FIG. 11, the caulkings 6 and 26 formed on the gaskets stacked upon each other are prevented from being fitted with each other. In other words, since the jam-preventing protrusions 40 are formed in this way, one stack-type gasket G, which is constituted by the stopper plate 21 and the bead plate 1, is prevented from being jammed with another stack-type gasket G' , which is placed thereover or thereunder.

Hereafter, various embodiments, which are differentiated from one another in the number and the forming position of jam- preventing protrusions 40, will be described in detail.

FIG. 6 illustrates a first embodiment of the present invention. In the present embodiment, when forming the jam- preventing protrusions 40a on a plurality of plates which constitute a stack-type gasket, the jam-preventing protrusions 40a are formed on the plate which is positioned the highest among the plates. With regard to the position where the jam- preventing protrusions 40a are formed, the jam-preventing protrusions 40a are formed on the valley portions ^Λb' of the caulkings 26 formed on the stopper plate 21, as shown in FIG. 6. With regard to the direction in which the jam-preventing protrusions 40a are formed, the jam-preventing protrusions 40a are formed to project in a direction opposite to the ridge portions ^λa' of the caulkings 26. By forming the jam- preventing protrusions 40a in this way, due to the presence of the jam-preventing protrusions 40a, the ridge portions "a' of the caulkings 6 formed on the bead plate 1 of another stack- type gasket are prevented from being jammed with the valley portions ^yb' of the caulkings 26 formed on the stopper plate 21 of one stack-type gasket, whereby it is possible to prevent the stack-type gaskets from being jammed with each other.

FIG. 7 illustrates a second embodiment of the present invention. In the present embodiment, when forming the jam- preventing protrusions 40b on a plurality of plates which constitute a stack-type gasket, the jam-preventing protrusions 40b are formed on the plate which is positioned the lowest among the plates. With regard to the position where the jam- preventing protrusions 40b are formed, the jam-preventing protrusions 40b are formed on the ridge portions ^a' of the caulkings 6 formed on the bead plate 1, as shown in FIG. 7. With regard to the direction in which the jam-preventing protrusions 40b are formed, the jam-preventing protrusions 40b are formed to project in the same direction as the ridge portions ^λa' of the caulkings 6. By forming the jam-preventing protrusions 40b in this way, due to the presence of the jam- preventing protrusions 40b, the valley portions ^λb' of the caulkings 26 formed on the stopper plate 21 of another stack- type gasket are prevented from being jammed with the ridge portions ^Λa' of the caulkings 6 formed on the bead plate 1 of one stack-type gasket, whereby it is possible to prevent the stack-type gaskets from becoming jammed with each other.

FIG. 8 illustrates a third embodiment of the present invention. In a plurality of plates which constitute a stack- type gasket, the jam-preventing protrusions 40c are formed on all of the plurality of plates. As shown in FIG. 8, with regard to the forming position of the jam-preventing protrusions 40c, the jam-preventing protrusions 40c are formed on the valley portions ^λb' of the caulkings 26 formed on the stopper plate 21 and the valley portions ^Λb' of the caulkings 6 formed on the bead plate 1. The jam-preventing protrusions 40c formed on the bead plate 1 are respectively inserted into the jam-preventing protrusions 40c formed on the stopper plate 21. With regard to the direction in which the jam-preventing protrusions 40c are formed, the jam-preventing protrusions 40c are formed to project in a direction opposite to that of the ridge portions ^Λa' of the respective caulkings 6 and 26. By forming the jam-preventing protrusions 40c in this way, due to the presence of the jam-preventing protrusions 40c, the ridge portions ^Λa' of the caulkings 6 formed on the bead plate 1 of another stack-type gasket are prevented from being jammed with the valley portions ^λb' of the caulkings 26 formed on the stopper plate 21 of one stack-type gasket, whereby it is possible to prevent the stack-type gaskets from becoming jammed with each other. In this case, due to the fact that the outer diameter Dl of the jam-preventing protrusions 40c formed on the stopper plate 21 is greater than the inner diameter D2 of the jam-preventing protrusions 40c formed on the bead plate 1, the jam-preventing protrusions 40c formed on the stopper plate 21 of one stack-type gasket are prevented from being inserted into the jam-preventing protrusions 40c formed on the bead plate 1 of another stack-type gasket, whereby the stack-type gaskets are prevented from being jammed with each other. In the case of the present embodiment, unlike the first and second embodiments, because the respective jam-preventing protrusions 40c can be simultaneously formed on the plurality of plates which constitute the stack-type gasket, advantages are provided in that the gasket can be easily manufactured.

FIG. 9 illustrates a fourth embodiment of the present invention. In a plurality of plates which constitute a stack- type gasket, the jam-preventing protrusions 4Od are formed on all of the plurality of plates. As shown in FIG. 9, with regard to the forming position of the jam-preventing protrusions 4Od, the jam-preventing protrusions 4Od are formed on the ridge portions ^λa' of the caulkings 26 formed on the stopper plate 21 and the ridge portions ^λa' of the caulkings 6 formed on the bead plate 1. The jam-preventing protrusions 4Od formed on the stopper plate 21 are inserted into respective jam-preventing protrusions 4Od formed on the bead plate 1. With regard to the direction in which the jam-preventing protrusions 4Od are formed, the jam-preventing protrusions 4Od are formed to project in the same direction as the ridge portions ^Λa' of the respective caulkings 6 and 26. By forming the jam-preventing protrusions 4Od in this way, due to the presence of the jam-preventing protrusions 4Od, the valley portions ^λb' of the caulkings 26 formed on the stopper plate 21 of another stack-type gasket are prevented from being jammed with the ridge portions ^λa' of the caulkings 6 formed on the bead plate 1 of one stack-type gasket, whereby it is possible to prevent the stack-type gaskets from being jammed with each other. In this case, due to the fact that the outer diameter D3 of the jam-preventing protrusions 4Od formed on the bead plate 1 is greater than the inner diameter D4 of the jam- preventing protrusions 40d formed on the stopper plate 21, the jam-preventing protrusions 4Od formed on the bead plate 1 of one stack-type gasket are prevented from being inserted into the jam-preventing protrusions 4Od formed on the stopper plate 21 of another stack-type gasket, whereby the stack-type gaskets are prevented from being jammed with each other. In the case of the present embodiment, unlike the first and second embodiments, because the respective jam-preventing protrusions 4Od can be simultaneously formed on the plurality of plates which constitute the stack-type gasket, an advantage is afforded in that the gasket can be easily manufactured.

FIG. 10 illustrates a fifth embodiment of the present invention. In a plurality of plates which constitute a stack- type gasket, the jam-preventing protrusions 4Oe are formed on all of the plurality of plates. As shown in FIG. 10, with regard to the forming position of the jam-preventing protrusions 4Oe, the jam-preventing protrusions 4Oe on the stopper plate 21 are formed to project in a direction opposite to the ridge portions ^Λa' of the caulkings 26 formed on the stopper plate 21, and the jam-preventing protrusions 4Oe on the bead plate 1 are formed to project in the same direction as the ridge portions ^Λa' of the caulkings 6 formed on the bead plate 1. By forming the jam-preventing protrusions 4Oe in this way, due to the presence of the jam-preventing protrusions 4Oe, the ridge portions ^λa' of the caulkings 6 formed on the bead plate 1 of another stack-type gasket are prevented from being jammed with the valley portions ^λb' of the caulkings 26 formed on the stopper plate 21 of one stack-type gasket, and the valley portions ^''b' of the caulkings 26 formed on the stopper plate 21 of another stack-type gasket are prevented from being jammed with the ridge portions ^Λa' of the caulkings 6 formed on the bead plate 1 of one stack-type gasket, whereby it is possible to prevent the stack-type gaskets from being jammed with each other. Hereafter, the operations of the jam-preventing stack-type gasket according to the present invention will be described with reference to FIG. 11. FIG. 11 illustrates the first embodiment of the present invention. When another stack type gasket G' constituted by the stopper plate 21' and the bead plate V is placed on the stack-type gasket constituted by the stopper plate 21 and the bead plate 1, and still another stack- type gasket G" constituted by the stopper plate 21" and the bead plate 1" is placed on another stack-type gasket G' , the respective stopper plates and the bead plates are coupled with each other by the caulkings, as shown in FIG. 11. In the stack-type gasket G placed lowest, since the upper stopper plate 21 has the jam-prevention protrusions 40a, the caulkings 26 formed on the stopper plate 21 of the stack-type gasket G are prevented from being inserted into the caulkings 6' formed on the lower bead plate V of the stack-type gasket G' , whereby the stack-type gaskets G and G' are prevented from becoming jammed with each other. Also, in the stack-type gasket G' placed in the middle and the stack-type gasket G" placed at the top, due to the presence of the jam-preventing protrusions 40a' formed on the stack-type gasket G' , the stack-type gaskets G' and G" are prevented from being jammed with each other.

While the above-described embodiments illustrated examples in which the stack-type gasket is only composed of the stopper plate and the bead plate, it is to be understood that the present invention is not limited to these examples. Therefore, in a stack-type gasket in which an inner plate is arranged between the stopper plate and the bead plate and these plates are coupled with one another using caulkings, by forming jam- preventing protrusions on the uppermost plate, the lowermost plate or all of the plates separately from the caulkings, it is possible to prevent stack-type gaskets from becoming jammed with each other.

Although a preferred embodiment of the present invention has been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims

[CLAIMS]

[Claim l]

A stack-type gasket including a plurality of plates which are coupled by means of caulkings, wherein jam-preventing protrusions are formed on the caulkings of at least one of the plates.

[Claim 2]

The stack-type gasket according to claim 1, wherein the jam-preventing protrusions are formed in valley portions of the caulkings of the uppermost plate in the plurality of plates in such a way as to extend in a direction opposite to ridge portions of the caulkings.

[Claim 3]

The stack-type gasket according to claim 1, wherein the jam-preventing protrusions are formed on ridge portions of the caulkings of the lowermost plate in the plurality of plates in such a way as to extend in the same direction as the ridge portions of the caulkings.

[Claim 4] The stack-type gasket according to claim 1, wherein the jam-preventing protrusions are formed in valley portions of the caulkings of the plates in such a way as to extend in a direction opposite to ridge portions of the caulkings.

[Claim 5] The stack-type gasket according to claim 1, wherein the jam-preventing protrusions are formed on ridge portions of the caulkings of the plates in such a way as to extend in the same direction as the ridge portions of the caulkings. [Claim 6]

The stack-type gasket according to claim 1, wherein the jam-preventing protrusions are formed on ridge portions and in valley portions of the caulkings of the respective outermost plates in the plurality of plates in such a way as to extend in the same direction as and in a direction opposite to the ridge portions of the caulkings, respectively.