Honeycomb structure and method for applying adhesive and brazing material to the structure
View Patent ↗A method for gluing and brazing a honeycomb structure includes at least one partially structured foil with a pitch and a wave height. The method includes the steps of choosing a mean brazing material diameter of a powder brazing material, said diameter being 15% smaller than the height of the wave; determining a minimum thickness of the glue strip according to equation; gluing at least partially structured foil within the width of the glue strip on at least part of the wave crests formed by the undulation; brazing the honeycomb structure. The invention also relates to a corresponding honeycomb structure that ensures satisfactory joint connections even when said structure is used in the exhaust systems of automobiles.
1. A method for producing a honeycomb structure, the method which comprises:
providing at least one at least partially structured foil having a pitch and a wave height defining a corrugation;
selecting an average brazing material diameter of a powderous brazing material that is smaller than 15% of the wave height;
determining a minimum adhesive strip width according to the equation:
B
=
2
·
D
·
[
1
4
·
P
W
-
0.0156
]
,
where B is the adhesive strip width, D is the average brazing material diameter, P is the pitch, and W is the wave height;
applying an adhesive at least to the at least partially structured foil within the adhesive strip width on at least some corrugation peaks formed by the corrugation;
applying brazing material to the honeycomb structure; and
brazing the at least partially structured foil within the adhesive strip width.
2. The method according to claim 1 , which further comprises enlarging the adhesive strip width by an additional width, the additional width being in a range between approximately (0.2·D)<Z<D.
3. The method according to claim 1 , which further comprises determining the adhesive strip width by a correction value lying in a range from 0 mm<K<1 mm, and one of:
subtracting the correction value from the adhesive strip width; and
adding the correction value to the adhesive strip width.
4. The method according to claim 1 , which further comprises:
first providing the at least partially structured foil with the adhesive;
subsequently forming the honeycomb structure; and
subsequently applying brazing material to an end side of the honeycomb structure.
5. The method according to claim 4 , which further comprises
forming the honeycomb structure by at least one additional smooth foil; and
at least one of stacking and winding the at least one structured foil and the at least one smooth foil to form ducts through which a fluid can flow.
6. The method according to claim 1 , which further comprises selecting the adhesive strip width to be less than 1.75 mm.
7. The method according to claim 1 , which further comprises selecting the adhesive strip width to be less than 1 mm.
8. The method according to claim 1 , which further comprises selecting the adhesive strip width to be less than 0.5 mm.
9. The method according to claim 1 , which further comprises carrying out the application of the adhesive to the honeycomb structure only over at least a region in a direction of an axis of the honeycomb structure.
10. The method according to claim 1 , which further comprises removing the adhesive that has collected outside the adhesive strip width in a cleaning step before applying the brazing material.
11. The method according to claim 1 , which further comprises:
providing the adhesive with two selectively adjustable adhesive properties that can each be activated or deactivated in a repeatable fashion; and
at least one of:
deactivating an adhesive property of the adhesive that has collected outside the adhesive strip width before applying the brazing material; and
activating an adhesive property of the adhesive that has collected inside the adhesive strip width before applying the brazing material.
12. The method according to claim 1 , which further comprises selecting the average brazing material diameter of the powderous brazing material to be between approximately 40 μm and approximately 120 μm.
13. The method according to claim 1 , which further comprises:
one of:
after applying the brazing material; and
after subsequent thermal treatment of the honeycomb structure,
generating a brazing material strip width that substantially has only a tolerance of at maximum 10% in comparison with the adhesive strip width.
14. The method according to claim 1 , which further comprises:
one of:
after applying the brazing material; and
after subsequent thermal treatment of the honeycomb structure,
generating a brazing material strip width that substantially has only a tolerance of at maximum 5%, in comparison with the adhesive strip width.
15. The method according to claim 13 which further comprises generating a brazing material strip width that substantially is not larger than the adhesive strip width.
16. The method according to claim 14 which further comprises generating a brazing material strip width that substantially is not larger than the adhesive strip width.
17. The method according to claim 1 , which further comprises introducing the honeycomb structure at least partially into a housing before applying the brazing material.