MXPA01000557A - Vehicle door reinforcing beam and method of making it - Google Patents

Abstract

A vehicle door reinforcing beam (18) cut and cold formed from a flat sheet of ultrahigh strength steel comprising a beam blank cut from a flat sheet of ultrahigh strength steel to provide an elongated generally flat central blank portion extending from end to end of the beam blank and integral side blank portions on opposite sides of the central blank portion. The central blank portion includes opposite end wall sections constructed and arranged to be fixedly secured to the vehicle door frame and an elongated central wall section extending between the end wall sections. The side blank portions include leg wall sections integral with the sides of the central wall section and bent by cold forming in a direction away from a flat surface of the central wall section to form a central reinforcing channel structure having leg section free ends defined by the leg wall sections adjacent the end wall sections and central wall section ends integral with the end wall sections. The centralblank portion (20) has notches (32) formed therein at positions inwardly of the leg section free ends so as to limit the occurrence of distortional stresses occasioned by the cold form bending of the side wall sections to those insufficient to distort the generally flat extent of the end wall sections with respect to the central wall section. A method of making the beam including the steps of cutting the blank from a sheet of ultrahigh strength steel and bending the leg sections in a cold forming operation is also enclosed.

Description

REINFORCEMENT BEAM FOR VEHICLE DOOR AND METHOD TO MAKE THE SAME Field of the Invention This invention relates to a reinforcement for vehicle door and more particularly to the formation of a reinforcement beam for a vehicle door.

Background of the Invention Reinforcing beams of the type contemplated herein are well known in the art. A typical commercially used beam is constructed in one piece from a channel structure formed by rollers or channel with ridges having separate end sections properly secured to opposite ends thereof. The fabricated structure is made of non-tempered steel and, after fabrication, the structure of the resulting beam is reburned in furnaces to give it high-strength characteristics. The requirement to separately fabricate at least three separate components and then assemble the components contributes materially to the costs involved in the production of the composite, composite beam. Another contributor of the cost is the REF: 125904 need to heat repair the beams after manufacture. There have been purposes in the patented literature to provide a beam with a one-piece construction. The examples are included in the descriptions of the following patents: U.S. Patent No. 4,919,473 and Japanese Patent Publication No. 8-258569. The approach taken apparently in these designs is to achieve adequate strength by shaping the beam with a steel that has a strength sometimes less than the high-strength steel and compensate for the lower strength of the material when building the beam with a transverse, impact-resistant configuration. Others have proposed to emit simplicity in the transverse configuration and have provided the required strength by initially forming a composite sheet. See, for example, U.S. Patent No. 5,272,341. The present invention is based on the gain of the strength required when using high-strength steel as a starting material, preferably to achieve the desired strength after shaping by heat tempering. The heat treatment of a steel sheet while still in a roll or coil formation is more economical than the heat treatment of individually manufactured structures although the heat process becomes almost as "continuous" as possible. The problem presented when using high-resistant steel as starting material is that it does not easily conforms to cold in three-dimensional configurations. Simple punching operations often result in the creation of internal stresses which can distort the portions of the steel sheet formed especially the flat sections. There is a need to provide a reinforcing beam of the type discussed which can overcome the problems noted above.

BRIEF DESCRIPTION OF THE INVENTION The disadvantages of the prior art can be overcome by providing a reinforcement beam for a cold-cut, cut-off vehicle door of a straightened sheet of high-strength steel comprising a beam pattern cut from a straightened sheet of hyper-resistant steel. to provide a central portion of the generally flat, elongated model extending from end to end of the beam model and side portions of the model on opposite sides of the central portion of the model. The central portion of the model includes opposite end wall sections constructed and arranged to be fixedly secured to the vehicle door structure and an elongated, central wall section extending between the end wall sections. The side portions of the model include wall sections of the wing or leg integral with the sides of the central wall section and bent by cold forming in a direction away from a flat surface of the section of. central wall to form a channel structure, reinforcement, central having free ends of the wing section defined by the wall sections of the wing adjacent to the end wall sections and the ends of the central wall section integral with the end wall sections. The central portion of the model has notches formed therein in the outward positions of the free ends of the wing section to limit the occurrence of distortionary stresses caused by the ing of the cold forming of the side wall sections to those insufficient to distort the generally flat extension of the end wall sections with respect to the central wall section.

Preferably, the high-strength steel sheet from which the model is cut is pre-breached and the wall sections of the flange are bent from the wall sections of the wing to provide a channel structure with flanges, reinforcement, central . According to another aspect of the invention, there is provided a method for making a reinforcement beam for a vehicle door that includes a central portion of the model, generally flat, elongated and side portions of the model, integral to the opposite sides of the portion. central of the model, in which the central portion of the model including opposite end wall sections constructed and arranged to be fixedly fixed to the structure of the vehicle door and a central, elongated wall section extending between the sections end wall and the side portions of the model include the wing wall sections integral with the sides of the central wall section extending in a direction away from a flat surface of the central wall section to form a wall structure. reinforcement channel, central that has free ends of the section of the wing defined by the wall sections of the wing adjacent to the sec end wall sections and center wall section ends integral with the end wall sections. The method comprises cutting a beam model of a straightened sheet of high-strength steel with a contour that defines the central and lateral portions of the model and notches in the central portion of the model in the inward positions of the free ends of the wing section and folding the wall sections of the wing on the side of the center wall section in a cold forming operation in such a way that the notches limit the occurrence of distortionary stresses to those insufficient to distort the overall flatness of the sections. of end wall with respect to the central wall section.

Description of the Drawings Figure 1 is a perspective view of a vehicle door reinforced with a beam incorporating the principles of the present invention; Figure 2 is a perspective view of the vehicle door reinforcement beam shown in dotted lines in Figure 1 which is constructed in accordance with the principles of the present invention; Figure 3 is an elevation, side view of the beam; Figure 4 is a top plan view of the beam; Figure 5 is a sectional, elongated view taken along line 5-5 of Figure 3; Figure 6 is a sectional, elongated view taken along line 6-6 of Figure 3; Figure 7 is a sectional, elongated view taken along line 7-7 of Figure 3; and Figure 8 is a sectional, elongated view taken along line 8-8 of Figure 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION Referring now more particularly to the drawings, there is shown here a vehicle door reinforced with a beam, generally indicated in FIG. , which incorporates the principles of the present invention. The door 10 has a conventional construction which includes an internally skeletonized structure 12 comprised of a thin sheet, an outer covering 14 and an interior panel 16. The internally skeletonized structure 12 is internally reinforced by a beam shown in dashed lines in Figure 1 and indicated generally at 18. The beam 18 is cold formed in accordance with the principles of the present invention of a beam model cut from a thin sheet steel with high resistance, previously tempered. The term "pre-tempering" as used herein refers to a steel sheet which is heat treated to improve its tensile strength characteristics while in an endless coil configuration and excludes steel which It has been treated with heat to improve the tensile strength after being manufactured. The term "high-strength steel" is steel that has a tensile strength of 84, 373,000 kilograms per square meter (120,000 psi) and above. The type of steel contemplated herein is the same as those examples set forth, described in U.S. Patent No. 5,306,058, the disclosure of which is hereby incorporated by reference into the present specification. The contour of the beam model which is cut from the straightened sheet of previously hardened, high-tensile steel defines the free edges of the beam 18 which is fixedly secured at its ends to the skeletonized structure 12 of the door between the outer skin 14 and the inner panel 16 thereof by any suitable means such as welding and the like.

As best shown in Figures 2-8, the outline of the beam model defines a central portion of the model, generally flat, elongate generally indicated at 20, extending from end to end of the beam model and side portions. of the model, integrals, generally indicated at 22, on the opposite sides of the central portion of the model 20. The central portion of the model 20 includes the flat, opposite, end wall sections 24 constructed and ordered to be fixedly secured to the structure of the vehicle door 12 and a central, elongated wall section 26 extending between the end wall sections 24. As seen from the drawings, the preferred construction of the end wall sections 24 and the The central wall section 26 is such that the opposingly facing flat surfaces defining each are arranged in parallel, common planes. The side portions of the model 22 include the wall sections of the wing 28 integral with the sides of the central wall section 26. The wall sections of the wing 28 are bent by cold shaping in a direction away from the flat surface of the central wall section 26 to form a channel, reinforcement, central structure which is generally U-shaped. The wall sections of the wing 28 terminate at the free ends of the section of the wing 30. According to With the principles of the present invention, the central portion of the model 20 is formed with the notches 32 therein in the outward positions of the free ends of the wing section 30. As can be seen from the drawings, the end wall sections 24 extend transversely outwardly from the notches 32 and the transverse extension of the elongated central wall section 26. The notches 32 are configured to limit the occurrence of stress is distortion caused by bending by cold shaping of the wall sections of the wing 28 to those insufficient to distort the generally flat extension of the end wall sections 24 with respect to the central wall section 26. In this way , the securing of the beam 18 to the structure of the door 12 in a condition which places it precisely between the outer cladding and the inner panel of the door is ensured. Preferably, the side portions of the model 22 are also folded by cold forming to define a pair of flange wall sections, which extend outwardly 34 over the central portion of the wall sections of the wing 28. As it can be seen from the drawings, the flange wall sections have opposite ends spaced inward from the free, opposite ends 30 of the wall sections of the wing 28. In addition, the transverse extension of each wall section of the wing 28 increases from the free ends 30 thereof to the adjacent end of the flange wall section 34 therein. The flange wall sections 34 which have a generally constant transverse length tend to provide additional strength to the beam 18 and to provide the reinforcing structure as a channel structure with flanges to achieve the added strength thereof. In a specific example of the method of • present invention, a beam model was cut from a martensitic steel sheet of .15748 cm (.062 inches) thick that has a tensile strength of 154,682,000 kilograms per square meter (220,000 .psi). The contour of the model included the central portion 20 and the lateral portions 22 in the configuration shown and the notches 32 in the location and configuration shown. The model was cut in a cold forming stamping operation during a cycle of movement of the cooperating cutting dies. The model was bent to form the wall sections of the wing 28 and the flange wall sections 34 in a cold forming stamping operation during a cycle of movement of cooperating bending dies. In the exemplary mode, cutting and bending operations were formed in different machines although both operations could be carried out in an individual machine. In this way, it will be noted that the objectives of this invention have been realized completely and effectively. However, it will be understood that the specific, preferred, prior embodiments have been shown and described for the purpose of illustration of the functional and structural principles of this invention and are subject to change without departing from such principles. Therefore, this invention includes all modifications encompassed within the scope of the following claims.

It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Having described the invention as above, the content of the following claims is claimed as property.

Claims (14)

1. A reinforcement beam for a cold-cut, cut-off vehicle door of a straightened sheet of high-strength steel, characterized in that it comprises: a beam model cut from a straightened sheet of hyper-resistant steel, the beam model having a central portion of the model, generally flat, elongated extending from end to end of the beam model and side portions of the model, integral to opposite sides of the central portion of the model, the central portion of the model including end wall sections, opposite, constructed and arranged to be fixedly secured to the structure of the vehicle door and a central, elongated wall section extending between the end wall sections, the side portions of the model including integral wing wall sections with the sides of the central wall section and bent by cold forming in a direction away from a flat surface of the sec center wall to form a channel, reinforcement, central structure having free ends of wing section defined by the wall sections of the wing adjacent to the end wall sections and ends of the integral central wall section with the end wall sections, the central portion of the model having notches formed therein in the outward positions of the free ends of the wing section to limit the occurrence of distortionary stresses caused by the bending of the conformation in cold of the side wall sections to those insufficient to distort the generally flat extent of the end wall sections with respect to the central wall section.

2. A reinforcement beam for vehicle door according to claim 1, characterized in that the portions of the model are bent by cold forming to provide a pair of flange wall sections extending outwardly on the wall sections of the vehicle. wing to form the reinforcement channel structure, central in a channel structure with flanges, reinforcement, central.

3. A vehicle door reinforcement beam according to claim 2, characterized in that the pair of outwardly extending flange wall sections have opposite ends spaced apart from the free ends of the wall sections of the wing, each the wall sections of the wing having a transverse extension which increases from the free ends thereof to the adjacent ends of the flange end section therein.

4. A reinforcement beam for a vehicle door according to claim 3, characterized in that the flange wall sections have generally constant transverse extensions.

5. A reinforcing beam for a vehicle door according to claim 4, characterized in that the end wall sections extend transversely outwards from the notches and the transverse extension of the central wall section.

6. A reinforcing beam for a vehicle door according to claim 5, characterized in that the end wall sections and the central section are defined by the opposing facing flat surfaces, arranged in parallel, common planes.

7. A reinforcing beam for a vehicle door according to claim 6, characterized in that the straightened beam of high-strength steel is martensitic steel having a thickness of approximately .1562 inches and a tensile strength of 154,682,000 kilograms. square meter (220,000 psi).

8. A reinforcement beam for a vehicle door according to claim 1, characterized in that the end wall sections extend transversely outwards from the notches and the transverse extension of the central wall section.

9. A reinforcing beam for a vehicle door according to claim 1, characterized in that the end wall sections and the central section are defined by the opposing facing flat surfaces, arranged in parallel, common planes.

10. A reinforcing beam for a vehicle door according to claim 1, characterized in that the straightened sheet of high-strength steel is martensitic steel having a thickness of approximately .1562 inches and a tensile strength of 154,682,000 kilograms per inch. square meter (220,000 psi).

11. A method for making a reinforcement beam for a vehicle door that includes a central portion of the generally flat, elongated model and side portions of the model, integral to opposite sides of the central portion of the model, in which the central portion of the model which includes the opposite end wall sections constructed and arranged to be fixedly secured to the vehicle door structure and an elongated central wall section extending between the end wall sections and the side portions of the model include wall sections of the wing with the sides of the central wall section extending in a direction away from a flat surface of the central wall section to form a reinforcing channel structure, central having free ends of the section of the wing defined by the wall sections of the wing adjacent to the end wall sections and ends of central wall section integr ales with the end wall sections. the method is characterized in that it comprises: cutting the beam of a straightened sheet of high-strength steel with a contour defining the central and lateral portions of the model and notches in the central portion of the model in positions inward of the free ends of the section of the to. and folding the wall sections of the wing on the side of the central wall section in a cold forming operation in such a way that the notches limit the occurrence of distortionary stresses to those insufficient to distort the generally flat extension of the sections of end wall with respect to the central wall section.

12. A method according to claim 11, characterized in that it includes the additional step of bending the flange wall sections transversely outwardly from the central portions of the wall portions of the wing.

13. A method according to claim 12, characterized in that the straightened sheet of high-strength steel is martensitic steel having a thickness of approximately .1562 inches (.1562) and a tensile strength of 154,682,000 kilograms per square meter (220,000 psi). .

14. A method according to claim 11, characterized in that the straightened sheet of hyper-resistant steel is martensitic steel having a thickness of approximately .1562 inches (.1562) and a tensile strength of 154,682,000 kilograms per square meter (220,000 psi). . SUMMARY OF THE INVENTION A reinforcement beam for vehicle door (18) cut and cold formed from a straightened sheet of high-strength steel comprising a beam model cut from a straightened sheet of high-strength steel to provide a central portion of the model, generally flat, elongated which extends from end to end of the beam model and the lateral portions of the model, integral to the opposite sides of the central portion of the model. The central portion of the model includes opposite end wall sections, constructed and arranged to be fixedly fixed to the vehicle door structure and a central, elongated wall section extending between the end wall sections. The side portions of the model include the wing wall sections integral with the sides of the central wall section and bent by cold forming in a direction away from a flat surface of the central wall section to form a channel structure reinforcement, central having free ends of the wing section defined by the wall sections of the wing adjacent to the end wall sections and the central wall section ends interengaged with the end wall sections. The central portion of the model (20) has notches (32) formed therein in positions inward of the free ends of the wing section to limit the occurrence of distortionary stresses caused by the bending of the cold forming sections of side walls to those insufficient to distort the generally flat extension of the end wall sections with respect to the central wall section. Also included is a method for making the beam that includes the steps of cutting the model of a sheet of high-strength steel and folding the sections of the wing in a cold forming operation.