Flat gasket and process for the production of a flat gasket

1. A flat gasket, comprising at least one metal gasket sheet made of a spring steel or a metallic material with a percentage elongation after fracture corresponding to the percentage elongation after fracture of a spring steel,

wherein the gasket sheet is provided with at least one edging fold, which comprises a bending region and a flange region connected in one piece to the gasket sheet via the bending region,

wherein the gasket sheet has a hole and the edging fold extends at least along one section of the periphery of the hole,

wherein the flat gasket has a vertically deformable bead extending around the hole,

wherein the bead is formed on the same gasket sheet that is also provided with the edging fold,

wherein the edging fold has a plurality of incisions, which extend from an outer edge of the flange region remote from the bending region into the flange region towards the bending region, and

wherein the average length of the incision-free regions of the outer edge of the flange region between the incisions arranged consecutively in the longitudinal direction of the edging fold is greater than the average extent of the incisions in the longitudinal direction of the edging fold at the outer edge of the flange region.

2. The flat gasket according to claim 1 , wherein the edging fold extends at least partially around a combustion chamber hole of the gasket sheet.

3. The flat gasket according to claim 1 , wherein the edging fold extends around the entire periphery of the hole.

4. The flat gasket according to claim 1 , wherein the edging fold forms a deformation restriction means, which restricts the vertical deformation of the bead extending around the hole.

5. The flat gasket according to claim 4 , wherein in addition to the edging fold the flat gasket comprises an outer deformation restriction means, which is arranged on the side of the bead remote from the hole.

6. The flat gasket according to claim 5 , wherein the outer deformation restriction means is arranged on the same gasket sheet that is also provided with the edging fold.

7. The flat gasket according to claim 5 , wherein the outer deformation restriction means commprises at least one deformation restriction element, which is formed by separating a region of a gasket sheet along a separating line and subsequently bending this region out of the plane of this gasket sheet.

8. The flat gasket according to claim 1 , wherein the flange region is folded over onto the gasket sheet itself.

9. The flat gasket according to claim 1 , wherein at least one of the incisions extends from the outer edge of the flange region into the bending region of the edging fold.

10. The flat gasket according to claim 9 , wherein the bending region has an inner edge remote from the flange region of the edging fold, and at least one of the incisions extends from the outer edge of the flange region and beyond the inner edge of the bending region.

11. The flat gasket according to claim 1 , wherein the edging fold extends at least in sections around a hole with a centre point, and the angular distance relative to the centre point of the hole of consecutive incisions in the peripheral direction of the hole amounts to approximately 1° to approximately 20°.

12. The flat gasket according to claim 11 wherein the angular distance relative to the centre point of the hole of consecutive incisions in the peripheral direction of the hole amounts to approximately 2° to approximately 15°.

13. The flat gasket according to claim 1 , wherein the edging fold is formed by producing the incisions in an edge region of a hole of the gasket sheet and subsequently folding over the edge region.

14. The flat gasket according to claim 1 , wherein the incisions are produced by mechanical cutting, punching or by laser cutting.

15. The flat gasket according to claim 1 , wherein the incisions are produced by cutting into the gasket sheet in a manner substantially without material loss.

16. The flat gasket according to claim 1 , wherein the flat gasket is multilayered.

17. The flat gasket according to claim 16 , wherein besides the gasket sheet, which is provided with the edging fold, the flat gasket additionally comprises at least one further gasket sheet, which is provided with at least one bead extending around a hole.

18. The flat gasket according to claim 16 , wherein besides the gasket sheet, which is provided with the edging fold, the flat gasket additionally comprises at least two further gasket sheets, between which the gasket sheet provided with the edging fold is arranged.

19. The flat gasket according to claim 16 , wherein besides the gasket sheet, which is provided with the edging fold, the flat gasket additionally comprises at least one support sheet with an angled section.

20. The flat gasket according to claim 19 , wherein the edging fold and the angled section extend around a hole, and the gasket sheet, which is provided with the edging fold, projects towards the centre point of the hole and over the support sheet, which is provided with the angled section.

21. The flat gasket according to claim 19 , wherein an angled region of the support sheet extends around a hole and comprises an inner section facing the hole and an outer section facing away from the hole, wherein the inner section has a smaller thickness than the outer section.

22. The flat gasket according to claim 1 , wherein besides the gasket sheet, which is provided with the edging fold, the flat gasket comprises at least one further gasket sheet, which has a reduced thickness in the region corresponding to the position of the flange region of the edging fold.

23. The flat gasket according to claim 1 which is a cylinder head gasket.