DE832520C - Combustion chamber seal for internal combustion engines of motor vehicles - Google Patents

Description

Combustion chamber seal for internal combustion engines of motor vehicles Invention relates to a seal for high pressures and high temperatures, such as especially in internal combustion engines of motor vehicles for the combustion chambers of Arbeitszylilider is required.

Seals previously used for these purposes, especially I> ei machines with a common head for several cylinders, exist z. B. from fibrous materials with binders, wherein in order to keep the fuel gases away from the fibrous material, the edges of the seal are crimped to the inside of the cylinder with sheet metal. By specifically gepreiten more edge surfaces of the seal takes place against the internal pressures during the remaining part of the seal under lower pressure, the sealing of the passages for cooling water and 01 takes over. Such seals are no longer sufficient at the high working pressures and temperatures such. B. occur in high-speed internal combustion engines with high performance, especially the metal part is not sufficiently pressed into the grooves and unevenness of the surfaces to be sealed and therefore requires very high pressure. Also is by the manufacturing tolerances that z. B. be several hundredths of a millimeter in the cylinder liners of in-line engines with a common cylinder head, the tight holding due to the small deformation path when compressing the relatively thin seal is very difficult.

Also meet the previously used metal rings not the requirements present at high pressures and high temperatures, since they are usually not so soft that they can be pressed sufficiently into the grooves and bumps of the surfaces to be sealed as well as pressing them into different ones as evenly as possible Sealing surfaces guaranteed with different heights due to manufacturing tolerances is.

One has, especially with storage tanks for very high tension Gases, ring-shaped seals made of soft iron or a similar building material are used, whose sealing edges with cutting edge shape lie against the surfaces to be sealed and deform plastically under the contact pressure. Such seals each have a sealing edge for the two surfaces to be sealed penetrate into the unevenness of these surfaces one and also bridge the differences in manufacturing stoles; satchel. On contact the metal sealing rings with highly heated turbulent gases leaves abex as a result of high Heating of the sealing edges of the contact pressure, pressure after, so that 'more or less large Leaks occur. When arranging several ring-shaped cutting edges one behind the other the deformability of the seal is too low for the purpose of the labyrinth effect.

The invention eliminates the shortcomings of the known seals and one that is well sealed and resistant to high pressures and high temperatures Gasket created, especially for high-speed internal combustion engines with high space efficiency and cylinder spacing reduced to the smallest possible extent is suitable in that a metallic sealing ring is provided on the its one side with a first sealing edge and one between this and the Inside the cylinder located second sealing edge and on its other side with one the first sealing edge is provided closer than the second sealing edge surface which rest on surfaces of the parts surrounding the pressure space to be sealed. The first sealing edge has the task of the actual seal, while the second the shielding of the first and the dissipation of heat from the sealing ring.

The sealing ring is designed so that it moves when pressed which can deform the sealing edges accordingly. For this purpose, according to the invention, the ring web of the sealing ring between the first and second sealing edge so dimensioned that it is bent by the pressure transferred to the second sealing edge. Advantageously the first and second sealing edge are dimensioned (height and width) so that the first the largest part (e.g. up to goo / o), the second the remaining part of the contact force records.

The first sealing edge is advantageously more or less pointed executed. As a result, there is a contact and cuddle path under plastic deformation this sealing edge possible. The second sealing edge can advantageously with a larger width than the first sealing edge anise formed, so that the second Edge against the effects of heat, e.g. B. from the brinknuiigsraum her is insensitive and, when tightened, dissipates heat well on its sealing surface. The main part the heat is passed through the sealing surface on the other side of the seal or sealing edge derived.

When pressing, the first sealing edge takes away from the one to be sealed Area the major part of the contact pressure under largely plastic deformation and passes it over the sealing surface on the other side of the seal directly to the other surface to be sealed. Since the other part to be sealed, z. B. the collar of the cylinder liner, generally finely machined, requires the seal at this point is multiple: no particularly high specific pressure.

The one between the first sealing edge and the space to be sealed The second sealing edge can also give way to a certain extent and reduce the deformation path the first sealing edge under its own deformation or partly more elastic, partly permanent Participate in the deformation of the inner part of the seal. Above all, it educates Keeping the highly heated, turbulent combustion gases away from the first sealing edge good protection for this. It is essential in the invention that for the second Sealing edge, despite lead; hen anpreßweges like that of the first sealing edge, only a small one Part of the contact pressure is required, so that the vast majority of this force for deforming the first sealing edge and bridging the unevenness well this is available.

In this way it is also possible without excessive increase in the Number of screws to achieve a sufficient contact pressure and often with the only four screws achievable contact pressure to achieve a good tightness.

It can be useful if there are large contact forces available be, in particular instead of one of the two on one surface of the sealing ring to attach several sealing edges provided. In turn, those of the edges away from the opening to be sealed, as described, the seal, the edges closer to this opening provide thermal insulation, regardless of the number and the shape of the individual sealing edges.

At the sealing point opposite the first and second sealing edge can also have a sealing edge or one or more instead of a sealing surface more or less pointed edges are attached, the latter especially if It is a question of less highly heated gases and special emphasis on one as possible great deformation and bridging ability of the seal is placed.

In order to give way to the second sealing edge over a certain pressing path (Al - s: hirmkante) with the lowest possible resistance, this can Edge of the opposite surface on the seal must be set down accordingly.

If the cylinder crankcase rests, Cylinder liners of internal combustion engines is the bearing surface for the seal on the advantage Cylinder liner within the diameter of the bearing surface of the cylinder liner placed on the crankcase. This has the advantage that on the collar of the cylinder liner no bending forces can act, rather the entire contact pressure, too in the case of a larger number of sealing edges, absorbed by pure pressure loading. This is particularly useful when the part in question, e.g. B. the cylinder liner with collar, made of gray cast iron.

The entire sealing ring, especially the third sealing point and the parts adjoining this are advantageously by a the parts to be sealed, e.g. B. an approach arranged on the cylinder liner, as known per se, shielded from the direct action of the hot gases. This approach can be used to advantage as a centering device for the seal. The deformation path of the part of the seal with the second sealing edge can also through the aforementioned recess on the seal also through recesses on the parts to be sealed, e.g. B. sleeve collar, are made possible.

The seal according to the invention is combined with particular advantage used with a soft seal, e.g. B. when in a cylinder head gasket Combustion chambers through metallic seals and the water or oil openings between the crankcase and the cylinder heads by Wei; h seals sealed will.

In the drawing are in Figs. T to 3 different embodiments of seals according to the invention for the combustion chambers of cylinders of internal combustion engines with retracted cylinder liners as partial cutouts on an enlarged scale shown in simple lines, all in the state before pressing.

In Figure 4 is a section through the seals of two adjacent Cylinders of a Bretmkraftmaschine reproduced in a pressed state.

In FIG. T, t denotes a small part of a crankcase of an internal combustion engine of a motor vehicle: 2 is a cylinder liner, 3 is the cylinder head; 4 is a metallic sealing ring with the annular projections 5 and 6. The sealing ring 4 is protected from the direct action of the hot gases by the part or projection 7 on the cylinder liner 2. 8 is the web of the sealing ring .4 between the first and second sealing edge, while 9 indicates the cylinder space of the Brelln engine. to is a surface on the cylinder head 3, 11 such a surface on the cylinder liner 2. The first sealing edge 12 arranged on the extension 5 and the second sealing edge 13 of the extension 6 lie against the former and the part 14 of the surface against the latter 15 of the sealing ring 4. The cylinder liner 2 rests with the surface 16 on the surface 17 of the crankcase 1. With an annular recess of the cylinder liner is designated. When the cylinder head 3 in Fig. T is pressed onto the crankcase by means of fastening screws (not shown), the cylinder liner 2. and the sealing ring 4 is mainly pressed with the first sealing edge 12 with plastic deformation of the same against the surface to of the cylinder head 3 and the surface 14 of the sealing ring 4 against the surface 11 of the collar on the cylinder bushing 2. The narrow, almost sharp-edged contact surface 12 is pressed into the unevenness of the sealing surface to of the cylinder head 3 and above all bridges the tolerated differences in thickness of the various cylinder collars of the machine. The main part of the heat that is supplied to the sealing ring 4 from the combustion chamber is dissipated through the sealing surface 14. The second sealing edge 13 serves primarily as good thermal protection for the first sealing edge 12; in addition, some of the heat is dissipated through this.

To the extent - to which the first sealing edge gives 12, and the neck 6 differs from the ring 4 with the second sealing edge 1 3 under partly elastic, partly permanent deformation. Dodging is made possible by the recess 1 8 in the cylinder liner. Such a recess can also be provided in the seal by turning back part of the surface 15. To fulfill the shielding task of the second sealing edge 13 of the projection 6 on the surface to, a significantly smaller contact pressure than that is sufficient. the first sealing edge 12. This is mainly achieved by deforming the sealing ring by bending the web B. Since the sealing surface 13 of the extension 6 is relatively wide, in any case wider than the first sealing edge 12, it is also less sensitive to the hot combustion gases. The main sealing edge can therefore benefit from the available contact force for the most part, while good thermal protection of the same is achieved by the flexible shielding edge 13 '.

In Figure 2 there is an edge on the lower surface of the sealing ring 4 21 with a subsequent slightly inclined surface 22 is provided. Instead of the first Sealing edge 12 of the embodiment according to FIG. T, two sealing edges 23 and 24 are provided. 'When this seal is tightened, to the extent that the edge 21 on the counterpart is pressed, the subsequent part of the surface 22 is used for sealing.

In Fig. 3, a cutting edge 28 is provided on the lower surface 27 of the sealing ring, the root 29 of which is 30 lower than the surface 27, so that when this seal is tightened, the cutting edge 28 deforms to approximately the height of the surface 27 of the sealing ring is reached.

In Fig. 4, 31 and 32 denote two adjacent cylinder sleeves an internal combustion engine, 33 and 34 the associated sealing rings, 35 the crankcase, 36 the cylinder head. The cylinder liner 31 has due to manufacturing differences a slightly higher collar than the cylinder liner 32, also lies the The bearing surface of the cylinder liner 32 on the crankcase 35 is lower than that of the cylinder liner 31. The first sealing edge 4 i of the sealing ring 33 is therefore somewhat more deformed than that 42 of the sealing ring 34, and the projection 43 of the second sealing edge 44 of the ring 33, as can be seen from the figure; under correspondingly due to the contact pressure greater bending or deformation of the web of this sealing ring a little further pressed downwards than is the case with the corresponding parts of the sealing ring 34 the case is. This makes the differences in height between the various bundles and the The contact surfaces of the cylinder liners are balanced. The differences that exist the contact pressure of the various sealing rings are relatively low.

Claims (9)

PATENT CLAIMS: i. Seal for high pressures and high temperatures, in particular the combustion chamber seal in internal combustion engines of motor vehicles, with a metallic sealing ring, characterized in that the sealing ring (4) has a first sealing edge on one side: (12) and one between this and the cylinder interior (9 ) located second sealing edge (13) and on its other side with one of the first surface (14) which is closer than the second sealing edge and which bears against surfaces (io, ii) of the parts to be sealed. 2. Seal according to claim i, characterized in that the sealing surface (14) the first sealing edge (12) is approximately directly opposite. 3. Seal according to claim i or 2, characterized in that the ring web (8) between the first and the second sealing edge is dimensioned so that it is through the on the second sealing edge (13) transferred pressure is bent. 4. Seal according to claim 1, 2 or 3, characterized characterized in that the first and the second sealing edge are dimensioned so that the first sealing edge most of the Aripreßkraft (700/0 or more), the second Sealing edge transfers the remaining part. 5. Seal according to claim 1, 2, 3 or 4, characterized in that the contact surfaces (14, I1) on the sealing ring (4) or on the part to be sealed (2) are so large that the heat introduced into the seal is derived for the most part through these surfaces. 6. Seal according to claim 1, 2, 3-4 or 5, characterized gekennzeic1liret that the sealing ring (4) in a manner known per se dur; @h one of the parts to be sealed (7) al) gede; kt is. 7. Seal according to one or more of the preceding claims, dadur # 7h characterized in that individual sealing edges are divided into several individual edges (23, 24) are. B. Seal according to one or more of the preceding claims, characterized in that on the side of the seal remote from the second sealing edge (13) shoulders (25) or recesses (18 ) are provided on the sealing ring or on the parts to be sealed or on both to enable Deformation paths. 9. Seal according to one or more of the preceding claims on the crankcase overlying cylinder liners, characterized in that the bearing surface (i i) the seal on the cylinder liner (2) within the diameter of the contact surface (16) of the cylinder liner lies on the crankcase (i). i o. seal after a or more of the preceding claims, characterized in that the first sealing edge opposite annular surface (22) of the sealing ring the surface (i i) of the part to be sealed is slightly inclined and a third seal: edge through which an end edge (21) of the annular surface is formed. i i. Seal after one or more of the preceding claims, characterized in that one Cutting edge sealing edge (28), the root (29) of which into the rest of the ring surface (27) is stuck so far over the latter that it protrudes when tightened the seal is pushed back to about the level of the ring surface.