1. Field of the Invention

|§O01] This invention relates generally to gaskets for providing a seal between two parts, and more particularly to multi-layer gaskets, such as cylinder head gaskets,

2. Related Art

|ΘΘΘ2| Gaskets are typically used to establish a gas and fluid tight seal between two parts clamped together, such as a cylinder head and an engine block of an internal combustion engine. Such gaskets oftentimes include a functional layer having a sealing bead, also referred to as an embossment:, to facilitate the tight seal. The functional layer with the sealing bead is typically provided along with one or more additional layers, and die multiple layers are compressed together between the two clamped parts _s in order to establish the gas and fluid tight seal However, if the gasket is over-compressed, damage can occur to the sealing bead. For example, if the bead becomes substantially flattened, it loses its ability to exert a high compression sealing pressure, and fatigue cracks can form in the area of the bead.

SUMMARY OF THE INVENTION

fWCBJ One aspect of the invention provides a gasket, such as a cylinder head gasket of an internal combustion engine. The gasket includes a first functional layer extending between a first edge and a second edge, wherein the first edge surrounds a combustion chamber opening. A first &!! bead is provided in the first functional layer and extends around the combustion chamber opening. The gasket also includes a second functional layer extending between a third edge also surrounding the combustion chamber opening and a fourth edge. The second functional layer includes a second full bead axially aligned with the first full bead. |O0O4] The gasket further includes a first stopper for preventing over- compression of the first full bead and a second stopper for increasing load on the second foil bead, promoting an even distribution of the load, and reducing head lift. The first stopper extends along the first functional layer between the first edge and the first full bead. The second stopper extends along the second full bead of the second functional layer. The second stopper also includes a third Ml bead having a contour matching the contour of the second i bead of the second functional layer. The combination of the layers, beads, and stoppers of the gasket provide improved performance under high loads and motion, compared to prior art gasket designs.

BRIEF DESCRIPTION OF THE DRAWINGS

fODOSJ Other advantages of the present invention will be readily appreciated, as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

[0006] Figure 1 is a radial cross-sectional side view of a cylinder head gasket according to a first exemplary embodiment of the invention;

[0007] Figure 2 is a radial cross-sectional side view of the cylinder head gasket according to a second exemplary embodiment of the invention;

[0008] Figure 3 is a radial cross-sectional side view of the cylinder head gasket according to a third exemplary embodiment of the invention; and

0 1 Figure 4 is a top view of the exemplary cylinder head gasket of Figure

1, wherein the cross-section shown in Figure 1 is taken along line 1-1 of Figure 4.

DESCRIPTION OF THE ENABLING EMBODIMENT

[OOIDJ Referring to the Figures, wherein like numerals indicate corresponding parts throughout the several views, a multilayer static gasket 20, 20* is generally shown in Figures 1 -4. The gasket 20, 20* is typically used to establish a gas and/or fluid-tight seal between two components clamped together, such as a cylinder head and engine block of an internal combustion engine of a vehicle. The gasket 20, 20' includes a first functional layer 22, 22 ^s extending between a first edge 24, 24' and a second edge 26, 26 and a second functional layer 28, 28 ^s extending between a third edge 30, 30* and a fourth edge 32, 3 *. The first edge 24, 24' of the first ftinctional layer 22, 22' and the third edge 30 _» 30* of the second functional iayer 28, 2Ψ surround a combustion chamber opening 34, 34 ^s . The first functional layer 22 _» 22' includes a first full bead 36, 36 ^s extending around the combustion chamber opening 34, 34% and the second functional layer 28, 28" includes a second foil bead 38, 38* axiaily aligned with the first foil bead 36, 36% A first stopper 40, 40* extends along the first functional Iayer 22, 22 ^s between the first edge 24, 24 ^s and the first full bead 36, 36' for preventing over-compression of the first &!! bead 36, 36% A second stopper 42, 42* extends along the second full bead 38, 38* of the second functional iayer 28, 28* for increasing load on the second full bead 38, 3§% promoting an even distribution of the load, and reducing head lift. The second stopper 42, 42 ^s includes a third full bead 44, 44* having a contour matching the contour of the second full bead 38 _s 38* of the second functional layer 28, 28%

poll] Figure 1 is a cross-sectional view of the gasket 20 according to a first exemplary embodiment. The first functional layer 22 of the gasket extends continuously between the first edge 24 presenting the combustion chamber opening 34 and the second edge 26. The second edge 26 of the first functional layer 22 presents an outer periphery or a second opening for allowing fluid or bolts to pass therethrough. The first functional layer 22 also presents a first outer surface 48 and an oppositely facing first inner surface 50 each extending from the first edge 24 to the second edge 26. The first outer surface 48 and the first inner surface 50 present a thickness j therebetween. The thickness t| is typically constant from the first edge 24 to the second edge 26. However, in alternate embodiments, the thickness ts can vary.

[§012] The gasket 20 typically includes multiple combustion chamber openings 34, each surrounded by the foil beads 36, 38, 44. Figure 4 is a top view of the exemplary gasket 21 of Figure 1 showing four combustion chamber openings 34 each having a cylindrical shape. However, the gasket 2 could include any number of combustion chamber openings 34, depending on engine for which the gasket 20 is designed, and those openings 34 could comprise another shape. The exemplary gasket 20 of Figure 4 also includes other types of openings, in addition to die combustion chamber opening 34 _» such as oil feed holes 54, coolant metering holes 56, bolt holes 5i, and oil drain back holes 60.

|0013J The first functional layer 22 of the exemplary gasket of Figure 1 presents the first full bead 36 disposed between the first edge 24 and the second edge 26. This first full bead 36 is closer to the first edge 24 than the second edge 26, and it extends circumferenti lly and continuously around the first edge 24. The first inner surface SO and the first outer surface 4S of the first functional layer 22 extend inwardly in a first direction ! _? which is toward the second functional layer 2S, to present the first full bead 36. As shown in Figure 1, the first inner surface SO of the first functional layer 22 is convex along the first full bead 36, and the first outer surface 4S of the first functional layer 22 is concave along the first full bead 36, The first inner surface 50 and the first outer surface 4S of the first functional layer 22 are typically planar between the first edge 24 and the first full bead 36.

|00141 The first functional layer 22 also includes a first half bead 62 disposed between the first foil bead 36 and d e second edge 26. The first half bead 62 typically extends along the second edge 26, and it may extend circumferentially and continuously around one of the secondary openings. The first inner surface S§ and the first outer surface 4S of the first functional layer 22 are typically planar in a region 64 between the first full bead 36 and the first half bead 62, and the first half bead 62 is formed by disposing a portion of the first inner surface 50 and the first outer surface 4S of the first functional layer 22 at an angle relative to the planar region 64. The first inner surface 5Θ and the first outer surface 48 of the first functional layer 22 extend in the first direction I to present the First half bead 62, which is the same direction as the first full bead 36, Between the first angled portion of the first half bead 62 and the second edge 26, the first inner surface 50 and the first outer surface 48 of the first fractional layer 22 are planar,

|0M51 The exemplary gasket 20 of Figure 1 also includes the second functional layer 2S extending continuously between the third edge 30 aligned with the first edge 24 and the fourth edge 32 aligned with the second edge 26. The third edge 30 presents the combustion chamber opening 34, just like the first edge 24. The second functional layer 2S presents a seeond outer surface 8 and an oppositely facing second inner surface 711 each extending from the third edge 30 to the fourth edge 32. The second outer surface 68 and the second inner surface 70 present a thickness ¾ tiierebetween, and the thickness t is typically constant from the third edge 3Θ to the fourth edge 32. In the exemplary embodiment, the thickness h of the second functional layer 2S is equal to the thickness 1 _$ of the first functional layer 22,

|00I | The second functional layer 2§ presents the second foil bead 3S which is axially aligned with the first full bead 36 of the first functional layer 22 and extends circumferentially and continuously around the third edge 30 of the second functional layer 28, The second inner surface 70 and the seeond outer surface 6§ of the seeond functional layer 2S extend inwardly in a second direction 2, which is opposite the first direction 1 and thus toward the first functional layer 22, to present the second full bead 3§. The second foil bead 38 is disposed between the third edge 30 and the fourth edge 32 of the second functional layer 28, and closer to the third edge 30 than the fourth edge 32. The seeond inner surface outer surface 68 of the second functional layer 28 is concave along the second Ml bead 38. The second inner surface 70 and the second outer surface 68 of the second functional layer 2S are typically planar between the third edge 30 and the second foil bead 38.

100171 The second functional layer 28 also includes a second half bead 72 axially aligned with and extending toward the first half bead 62. The second half bead 72 is disposed between the second foil bead 38 and the fourth edge 32 of the second functional layer 28. The second half bead 72 typically extends along the fourth edge 32, and it may extend cireumferentially and continuously around one of the secondary openings, just like the first half bead 62. The second inner surface 7Θ and the second outer surface 68 of the second functional layer 28 are planar in a region 65 between the second fell bead 38 and the second half bead 72, and portion of the second inner surface 7Θ and the second outer surface 68 of the second functional layer 28 is disposed at an angle relative to the planar region 65 to present the second half bead 72. The second inner surface 70 and the second outer surface 68 of the second functional layer S extend in the second direction 2 to present the second half bead 72. Between the second angled portion and the fourth edge 32, the second inner surface 70 and the second outer surface 68 of the second functional layer 28 are planar.

{WIS] The gasket 20 according to the exemplary embodiment of Figure 1 also includes a distance layer 74 disposed between the first functional layer 22 and the second functional layer 28. The distance layer 74 is not required, but may be present to provide additional support, prevent over-compression, or adjust the distribution of the load along the gasket 20, The di tance layer 74 extends continuously between a fifth edge 78 aligned with the first edge 24 and a sixth edge 8(1 aligned with the second edge 26, and the distance layer 74 presents a first surface 82 and an oppositely facing second surface 84 each extending from the fifth edge 78 to the sixth edge 8 . The first surface 82 and the second surface §4 of the distance layer 74 present a thickness therebetween. In the exemplary embodiment, the thickness % of the distance layer 74 is greater than the thickness i _% , t2 of the functional layers 22, 28 and is generally constant from the fifth edge 78 to the sixth edge 8§,

fOOl J In the exemplary embodiment of Figure 1, the distance layer 74 includes a stepped region 88 located radially between the foil beads 36, 38, 44 and the fifth edge 78. The first surface §2 and the second surface §4 of the distance layer 74 are planar in a region between the fifth edge 78 and the stepped region SB and planar in a region between the stepped region 88 and the sixth edge 80. The stepped region §§ Is formed by disposing a portion of the first surface 82 and the second surface 84 of the distance layer 74 at an angle relative to the planar regions 64, 65. The distance layer 74 is typically extended or bent in the first direction 1 or the second direction 2 to present the stepped region §8, As shown in Figure I, a first portion 90 of the first surface 82 of the distance layer 74 located between the fifth edge 78 and the stepped region 88 is farther from the first functional layer 22 than a second portion 92 of the distance layer 74 located between the stepped region 88 and the sixth edge 80.

|0§2§| The gasket 20 of the exemplary embodiment of Figure 1 also includes the first stopper 40 extending along the first inner surface 50 of the first functional layer 22, circumferential!y around the first edge 24, and between the first edge 24 and the first full bead 36 for preventing over-compression of the first foil head 36, The first stopper 40 typically extends from a first stopper end 94 located at the first edge 24 to a second stopper end 96 located between the first edge 24 and the first full bead 36, However, the length of the first stopper 40 can vary. The first stopper 40 presents a first stopper surface 98 extending along the first inner surface 50 of the first functional layer 22 and a second stopper surface 100 facing opposite the first stopper surface 9§ and toward the distance layer 74, The first stopper surface 98 and the second stopper surface 100 present a thickness therebetween, which is less than the thickness tj, ¾ of the functional layers 22, 28, However, the thicknesses t$ of the first stopper 40 can vary. The first stopper surface PS is typically attached to the first inner surface 50 of the first functional layer 22 continuously from the first stopper end 94 to the second stopper end 96, The first stopper 40 can be attached to the first ftmedonal layer 22 by welding, such as laser welding, or by other methods. The first stopper 40 eonld alternatively be mechanically fixed to the first functional layer 22.

f0021J The gasket 2D of the exemplary embodiment of Figure 1 also includes the second stopper 42 formed with the second foil bead 38 of the second functional layer 28, The second stopper 42 increases the load on the second full bead 3S, reduces head lift, and promotes an even distribution of the load when the gasket 20 is compressed between two parts. The second stopper 42 extends along the seeond inner surface 70 of the second functional layer 28, along the second &li head 38, and between the third edge 30 and the fourth edge 32 of the second functional layer 28. In the exemplary embodiment of Figure ! , the second stopper 42 extends from a third stopper end 102 aligned with the third edge 30 to a fourth stopper end 104 located between the third edge 30 and the fourth edge 32, and closer to the fourth edge 32 than the third edge 30. However, the length of the second stopper 42 can vary. The second stopper 42 presents a third stopper surface 106 extending along the second inner surface 70 of the second functional layer 28 and a fourth stopper surface 108 facing opposite the first stopper surface 98 and toward the distance layer 74. The third stopper surface 106 and the fourth stopper surface 108 present a thickness therebetween, which in the exemplary embodiment is less than the thicknesses t of the functional layers 22, 28. The thickness of the second stopper 42 could be equal to, greater than, or less than the thickness f.3 of the first stopper 40, Typically, the thickness of the second stopper 42 is not less than the thickness of tlie first stopper 40. The tliird stopper surface !0# is typically attached to the second functional layer 28 continuously from the third stopper end 102 to the

S fourth stopper end 104. In the exemplary embodiment, the third stopper surface 106 is welded to the second inner surface 70 of the second functional layer 2S _f but the second stopper 42 could be attached to die second functional layer 28 using other methods. For example, the second stopper 42 could be mechanically fixed to the second functional layer 28.

|0 22] As shown in the Figures, the second stopper 42 presents the third full bead 44 between the third stopper end 102 and the fourth stopper end 1Θ4. The third foil bead 44 and the second foil bead 38 are typically formed together, after attaching the second stopper 42 to the second functional layer 2§, and thus have matching contours or profiles. Alternatively, the second foil bead 3S in the second functional layer 28 and the third full bead 44 in the second stopper 42 could be formed separately before attaching the second stopper 42 and the second functional layer 28 together, but the second full bead 3S and the third full bead 44 would still have matching contours. The third stopper surface 106 is concave along the third foil head 44 and the fourth stopper surface 108 is convex along the third full bead

|0023J Ess of the layers 22, 28, 74 and the stoppers 4% 42 of the gasket 2Θ are typically formed, of a steel material, such as a steel material including chromium and nickel. Exemplary materials include SS301 folly hardened spring stainless steel material, cold rolled stainless steel, or SS304 annealed stainless steel Alternatively, the layers 22, 28, 74 and stoppers 40, 42 of the gasket 20 could be formed of another metal or non-metal material

[0024] The gasket 20 can include multiple sets of the fimctional layers 22, 28 and stoppers 4 42 shown in Figure 1 , For example, the gasket 20 can include multiple first functional layers 22 and corresponding first stoppers 40, and/or multiple second functional layers 28 and corresponding second stoppers 42. The gasket 20 can also include additional distance layers 74. Also, although not shown, the orientation of the layers 22, 28, 74 and stoppers 40^ 42 of the gasket 20 of Figure 1 could be reversed, such that the second functional layer 28 is disposed above the first functional layer 28,

[D0251 A second exemplary cylinder head gasket 20 is shown in the cross- sectional view of Figure 2, In this embodiment, the gasket 21) includes two sets of the functional layers 22,, 2S stacked one on top of the other. Unlike the gasket 20 of the first exemplary embodiment, this gasket 2§ does not include any distance layer 74, As in Figure

1, the orientation of the layers 22, 28 and stoppers 40, 42 of the gasket 20 of Figure 2 could be reversed.

[00261 A third exemplary embodiment of the gasket 2Θ* is shown in Figure 3, also in cross-section. This gasket 20* includes the first functional layer 22* and the second fimctiooal layer 2 having the same design as the functional layers 22, 2§ of Figures 1 and

2, However, in this case, the second functional layer 28* is disposed above the first functional layer 22 ⁵ . Thus, the location of the first inner sorfaee 50' and the first outer surface 48* of the first functional layer 22' are reversed, as well as the location of the second inner surface 70' and the second outer surface 68* of the second functional layer 28'. The first full bead 3 ^s and the second mil bead 38' extend outwardly away from one another, and the first half bead 62* and the second half bead 72* also extend outwardly away from one another. The first outer surface 48" of the first functional layer 22* is convex along the first full bead 36* and the first inner surface 50* of the first functional layer 22' is concave along the first full bead 36 ^s ; and the second outer surface 6§* of the second functional layer 28* is convex along the second full bead 38* and the second inner surface 70* of the second functional layer 2 is concave along the second foil bead 38*.

f©027J As shown in Figure 3, the gasket 20 ^s of the third exemplary embodiment also includes the distance layer 74* disposed adjacent the first outer surface 4§* of the first functional layer 22* and extending continuously between the fifth edge 78 ^s aligned with the first edge 24' and the sixth edge 8iP aligned with the second edge 26 ^s , However, in this embodiment, the thickness of the distance layer 74 is less than the thickness of fee functional layers 22% 28* and the first surface 82* and the second surface 84' of the distance layer 74* are planar from the fifth edge 7S* to the sixth edge §§\

[0928J The gasket 2§ ⁵ of the third exemplary embodiment also includes the first stopper 40* and the second stopper 42*. The first stopper 4©' extends along the first outer surface 4§' of the first functional layer 22 ^s between the first edge 24* and the first full bead 36 * for preve ting over-compression of the first full bead 36 * _s and the second stopper 42 extends along the second outer surface 68' of the second full bead 38* of the second ftmctional layer 28* between the third edge 3¥ and the fourth edge 32" for increasing load on fee second Ml bead 38 ^s , reducing head Kit, and promoting even distribution of the load. The second stopper 42* is typically formed with the second functional layer 2§\ but may be formed separate from the second ftmctional layer 28*, as discussed above,

|0§291 to &e exemplary embodiment of Figure 3, the gasket 20* also includes a third functional layer S6 disposed adjacent the fourth stopper surface 1§8' and the second outer surface 68' of the second functional layer 28'. The third ftmctional layer S6 and the first functional layer 22' have matching contours _f but no stopper is disposed along the third functional layer 86.

[00301 T¾ ^e third functional layer §6 extends continuously between a seventh edge 110 aligned with the first edge 24 ^s and an eighth edge 112 aligned with the second edge 26 ^s . The third functional layer §6 also presents an third outer surface 114 and an oppositely facing third inner surface 116 each extending from the seventh edge 110 to the eighth edge 112. The third outer surface 114 and the third inner surface 116 present a thickness t§ therebetween, and the thickness t$ is constant from the seventh edge 10 to fee eighth edge 112. In the exemplary embodiment, the thickness tg of the third functional layer §6 is equal to the thickness tj ⁵ of the first functional layer 22 and the thickness of the second functional layer 2§ ⁹ .

[0031J The third functional layer §6 presents a fourth full bead §2 axially aligned with the other Ml beads 36% 3S% 44' of the gasket 2u\ as shown in Figure 3, The fourth foil bead 52 is disposed between the seventh edge 110 and the eighth edge 112, but is closer to the seventh edge 11$ than the eighth edge 112. The third inner surface 116 and the third outer surface 1 4 of the third functional layer 86 extend in the first direction 1, which is inwardly toward the second functional layer 2S% to present the fourth full bead 52, The third inner surface 116 of the third functional layer §6 is convex along the fourth full bead 52 and the third outer surface 114 of the third functional layer 86 is concave along the fourth full bead 52, Like the other full beads 36% 38% 44% the fourth foil bead 52 extends circumferentially and continuously around the combustion chamber opening 34 ^s , The third inner surface 116 and the third outer surface 114 of the third functional layer 86 are typically planar between the seventh edge 11§ and the fourth full bead 52,

[©0321 T¾@ rtwd functional layer 86 also includes a third half bead 76 axially aligned with the first half bead 62" and the second half bead 72*. The third half bead 76 is disposed between the fourth foil bead 52 and the eighth edge 112, The third half bead 76 typically extends along the eighth edge 1 2, just like the od er half beads 62% 72*. The third inner surface 116 and the third outer surface 114 of the third functional layer 86 are p!auar in a region 67 between the fourth full bead 52 and the third half bead 76. The third half bead 76 is typically formed by disposing a portion of the third inner surface 116 and the third outer surface 114 of the third functional layer §6 at an angle relative to the planar region 67. For example, the third functional layer §6 can be bent in the first direction 1 or tire second direction 2 to present the third half bead 76, The third inner surface 116 and the third outer surface 114 of the third functional layer 86 are planar between the third angled portion and the eighth edge 112.

100331 Of course, the orientation of the layers 22 28 ^s , 74 86* and stoppers

40* 42* of the gasket 2fP of Figure 3 could be reversed, such that the first functional layer 22 ^s is the uppermost layer. Ob iously, many modifications and variations of the present invention are possible in light of the above teachings and may be practiced otherwise than as specifically described while within the scope of the appended claims.