A bumper system for motor vehicles has a cross-member and two crush boxes. The cross-member is made from steel and the crush boxes are made from aluminum, or vice versa. The bumper member that is made from steel has a zinc coating on at least the joint area thereof. A braze weld fixedly connects the crush boxes to the cross-member along associated joints.
1. A bumper system for motor vehicles, comprising:
a cross-member having a joint area, and being constructed from one of a steel material and an aluminum material;
at least one crush box having inner and outer ends and a peripheral edge extending around the entire inner end and defining a joint area, and being constructed from the other one of said steel material and said aluminum material; and wherein
said one of said cross-member and said crush box that is constructed from said steel material has a zinc coating on at least said joint area thereof; and including
a braze weld extending around substantially the entire peripheral edge and fixedly connecting said joint area of said cross-member with said joint area of said crush box.
2. The bumper system as set forth in claim 1 , wherein:
said zinc coating has a thickness in the range of 5 μm to 50 μm.
3. The bumper system as set forth in claim 1 , wherein:
said one of said cross-member and said crush box that is constructed from said steel material has a thickness in the range of 1 mm to 3 mm; and
said one of said cross-member and said crush box that is constructed from said aluminum material has a thickness in the range of 1 mm to 4 mm.
4. The bumper system as set forth in claim 1 , wherein:
said cross-member is constructed from said steel material having a tensile strength Rm in the range of 800 MPa to 1,800 MPa; and
said crush box is constructed from said aluminum material having a tensile strength in the range of 85 MPa to 350 MPa.
5. The bumper system as set forth in claim 1 , wherein:
said zinc coating comprises either a thermal diffusion layer or a powder coating.
6. The bumper system as set forth in claim 1 , including:
mounting plates constructed from said other one of said steel material and said aluminum material connected with an end of said crush box facing away from said cross-member by a material bond.
7. A bumper system for motor vehicles, comprising:
a cross-member having an elongated rear surface, the rear surface defining a joint area that faces generally rearwardly, and wherein the cross-member is constructed from one of a steel material and an aluminum material;
at least one crush box having an outer edge and an outer surface immediately adjacent the outer edge facing transversely relative to the rear surface of the cross-member, the outer surface defining a joint area, and wherein said crush box is constructed from the other one of said steel material and said aluminum material; and wherein
said one of said cross-member and said crush box that is constructed from said steel material has a zinc coating on at least said joint area thereof; and including
a braze weld fixedly connecting said joint area of said cross-member with said transversely facing joint area of said outer surface of said crush box.
8. The bumper system as set forth in claim 7 wherein:
said outer edge of the crush box forms a portion of the joint area and includes a vertically-extending portion, and a portion extending transverse relative to said vertically-extending portion.
9. The bumper system as set forth in claim 8 wherein:
said vertically-extending portion is substantially linear.
10. The bumper system as set forth as claim 7 , wherein:
the outer surface is substantially planar.
11. A bumper system for motor vehicles, comprising:
a cross-member having a non-planar joint area, and being constructed from one of a steel material and an aluminum material;
at least one crush box having an edge defining a non-planar joint area having a shape that closely corresponds to said non-planar joint area of the cross-member, and being constructed from the other one of said steel material and said aluminum material; and wherein
said one of said cross-member and said crush box that is constructed from said steel material has a zinc coating on at least said joint area thereof; and including
a braze weld fixedly connecting said non-planar joint area of said cross-member with said non-planar joint area of said crush box.
12. The bumper system as set forth in claim 11 , wherein:
said crush box defines a peripheral outer surface, and said braze weld extends around substantially the entire peripheral outer surface.
13. The bumper system as set forth in claim 11 , wherein:
said cross-member has a generally curved shape in plan view and an upright elongated generally convex rear surface having end portions that extend outwardly and rearwardly adjacent said joint areas.