Patent Application
20200406837
The disclosure relates generally to a vehicle frame assembly using a strengthened glass cover layer, and specifically to a vehicle frame cover utilizing a thin, thermally strengthened, glass cover panel. Vehicle frames typically include a variety of rigid (typically metal) support pillars, beams, etc. A body panel is typically attached to the frame to provide a shape, color, appearance, etc. as desired to the vehicle body.
One embodiment of the disclosure relates to a vehicle frame assembly. The vehicle frame assembly includes a vehicle frame support structure having an interior surface and an exterior surface. The vehicle frame assembly includes a cover panel coupled to the vehicle frame support structure and covering the exterior surface of the vehicle frame support structure. The cover panel includes a glass article. The glass article includes a first major surface, a second major surface opposite the first major surface and separated from the first major surface by a thickness and an interior region located between the first and second major surfaces. The thickness is less than or equal to 2 mm. The glass article is thermally strengthened such that at least one of the first major surface and the second major surface is under compressive stress greater than 60 MPa. The first major surface faces the exterior surface of the vehicle frame support structure.
An additional embodiment of the disclosure relates to a method of forming a vehicle frame assembly. The method includes bending a glass article to a curved shape while a temperature of the glass article is less than a glass transition temperature of the glass article. The glass article includes a first major surface, a second major surface opposite the first major surface and separated from the first major surface by a thickness and an interior region located between the first and second major surfaces. The thickness is less than or equal to 2 mm. The glass article is thermally strengthened such that at least one of the first major surface and the second major surface is under compressive stress greater than 60 MPa. The method includes coupling the glass article to a vehicle frame such that the glass article is held in place relative to the vehicle frame covering a portion of the vehicle frame.
An additional embodiment of the disclosure relates to a glass cover panel for covering a portion of a vehicle frame that includes a thermally strengthened glass article. The thermally strengthened glass article includes a first major surface, a second major surface opposite the first major surface and separated from the first major surface by a thickness that is less than or equal to 2 mm, and an interior region located between the first and second major surfaces. The glass article is thermally strengthened such that at least one of the first major surface and the second major surface is under compressive stress greater than 60 MPa. The glass article is not chemically strengthened such that an ion content and chemical constituency of at least a portion of both the first major surface and the second major surface is the same as an ion content and chemical constituency of at least a portion of the interior region. At least a portion of the first major surface is a curved surface comprising a first radius of curvature, wherein the first radius of curvature is between 500 mm and 3000 mm. The cover panel includes a non-transparent colored layer located on the first major surface of the thermally strengthened glass article.
Additional features and advantages will be set forth in the detailed description that follows, and, in part, will be readily apparent to those skilled in the art from the description or recognized by practicing the embodiments as described in the written description and claims hereof, as well as the appended drawings.
It is to be understood that both the foregoing general description and the following detailed description are merely exemplary, and are intended to provide an overview or framework to understand the nature and character of the claims.
The accompanying drawings are included to provide a further understanding and are incorporated in and constitute a part of this specification. The drawings illustrate one or more embodiment(s), and together with the description serve to explain principles and the operation of the various embodiments.
Referring generally to the figures, various embodiments of a vehicle frame cover panel formed from a thin, thermally strengthened glass article are shown and described. In general, the vehicle frame cover panel discussed herein is formed from a thermally strengthened glass article having a high level of strengthening to provide for high levels of strength, durability, scratch resistance, dicing performance, etc. as needed for a vehicle body or frame cover application. While providing sufficiently high levels of strengthening, the glass article also is very thin (e.g., less than 2 mm) which provides both a low weight frame cover material and a glass material that can be shaped as desired using cold bending processes.
It is Applicant's understanding that prior attempts to utilize thermally strengthened glass in vehicle frame cover applications has focused on thick glass (e.g., typically thicker than 2.8 mm) to provide sufficient levels of strengthening. However Applicant has found that the thick, thermally strengthened glass for frame cover applications adds additional weight to the vehicle. Further, due to the high level of thickness, such prior glass frame cover panels typically required hot bending equipment and processes to form the curved shapes typically desired in vehicle frame cover applications. As such, Applicant believes that the vehicle frame cover panel discussed herein provides a unique combination of low weight, high strength and/or cold-bending that was not achievable with prior thick glass cover panel designs.
In addition, prior vehicle frame cover panels have been formed from plastic materials and from painted metal materials. Applicant believes that the glass frame cover panels discussed herein provide for a variety of improved performance characteristics relative to these alternative cover panel designs. As one example, by utilizing a glass material for the frame cover panel, a consistent body appearance is provided by the frame cover panels located adjacent to the glass vehicle glazing (e.g., vehicle windows, windshield, sunroof, etc.). As compared to plastic frame cover materials, the glass frame cover panels discussed herein provide for a more durable and scratch resistant vehicle body material. As compared to metal cover materials, the glass frame cover panels discussed herein are believed to provide for improved color and appearance matching, glossy appearance and/or scratch resistance. As compared to thicker glass materials, the glass frame cover panels are thin and light while maintaining a high level of strength. Weight reduction in vehicle frame materials has become an increasingly more important design objective to achieve high levels of fuel efficiency and may become even more important in helping to enable practical, low weight, long range electric vehicles.
Referring to
Referring to
As noted above, frame assembly 20 includes a frame support structure, shown as the A pillar 16. Pillar 16 includes an interior surface 22 and an exterior surface 24. Interior surface 22 faces toward the vehicle interior and/or vehicle passenger compartment 26, and exterior surface 24 faces outward toward the exterior of the vehicle.
Frame assembly 20 includes a cover panel 30. In general, cover panel 30 is coupled to pillar 16 such that its exterior surface 24 is covered by cover panel 30. In the embodiments discussed herein, cover panel 30 is formed from a thin thermally strengthened sheet or article of glass material (as will be discussed in more detail below regarding
In general and as shown in
In various embodiments, interior surface 32 and/or exterior surface 34 of cover panel 30 are defined by the glass material of the glass article of cover panel 30 (see
As shown in
In the specific embodiment shown in
In specific embodiments, outer surface 24 of pillar 16 is a curved surface defined by one or more radius of curvature, shown as radius of curvature R1. It should be understood that while the cross-sectional view of
Referring to
As shown, cover panel 30 includes a peripheral edge 54 that extends between and surrounds upper and lower surfaces 32 and 34 of cover panel. Panel frame 52 includes a first end, shown as flange 56, which overlaps and engages a portion of outer surface 34 of cover panel 30 adjacent to peripheral edge 54. Panel frame 52 includes a second end, shown as collar 58, which engages a portion of pillar 16. In this manner, the frictional engagement provided by panel frame 52 couples cover panel 30 to pillar 16. In various embodiments, a wide variety of frictional engagement structures, such as snap fit arrangements, press fit arrangements, taper fit arrangements, etc., may be used to provide the frictional coupling between panel frame 52, cover panel 30 and pillar 16. In some embodiments, the frictional coupling of panel frame 52 may be combined with various adhesive materials such as adhesive layer 40 discussed above.
Referring to
In specific embodiments, cover panel 30 is cold-bent or cold-formed to the curved shape shown in
In addition, following or contemporaneous with bending, the method of assembling a vehicle frame assembly includes coupling the cover panel to a vehicle frame such that the cover panel is held in place relative to the vehicle frame and such that the cover panel covers a portion of the vehicle frame. Specifically, in the embodiments shown, cover panel 30 is coupled to pillar 16.
In one embodiment, cover panel 30 is coupled to pillar 16 via an adhesive material such as adhesive layer 40 shown in
In another embodiment, cover panel 30 is coupled to pillar 16 via a friction engagement, such as provided by panel frame 52, shown in
As a specific explanation of the cold-bending enabled by the thin glass material of cover panel 30 discussed herein, the stiffness of an article of glass is proportional to the cube of its thickness, as shown by Equation 1 below. A much greater force is required to bend a thick article of glass to a given radius of curvature than is needed to bend a thin article of glass to the same radius of curvature. The bending of glass to a specific radius results in the production of a bend stress (m) in the glass, as shown by Equation 2 below.
where D is Flexural Rigidity (stiffness), E is Young's Modulus of soda-lime glass, t is the glass thickness, and v is Poisson's ratio for glass.
where E is Young's Modulus of soda-lime glass, t is the glass thickness, and R is radius of curvature.
Thus, the lower stiffness of the thin glass article used for cover panel 30 discussed herein results in a lower applied bend stress for a specific radius. For example, assuming a cover panel 30 that is bent to a fixed radius R, a thin, thermally strengthened soda-lime glass substrate of 0.7 mm thickness has 1/64th the stiffness and ¼th the induced bend stress of a 2.8 mm thick, conventionally strengthened soda-lime glass substrate with the same bend (i.e., the same fixed radius R). Thus, Applicant has found the thin thermally strengthened glass article discussed herein enables the use of cold bending to form a flat glass article into a non-flat shape of cover panel 30 without the need to heat the glass material to the glass softening temperature. For a cover panel application produced through cold bending, the thin glass article is selected to be thin enough to enable it to conform to the vehicle surface or to the upper surface of the plastic assembly element it is attached to while also meeting the reliability strength requirements for long term bending (fatigue) including the stresses of the in-service environment.
In specific embodiments, the thin glass cover panels, such as cover panel 30, discussed herein are particularly suited for use on vehicle locations where direct mechanical impacts (i.e., stones) from the road surface are not very likely. In such positions, in the event of an impact, the trajectories are at glancing angles, which minimize damage introduction and impact energy.
Referring to
As shown in
In various embodiments, T1 is less than 2 mm, specifically is 0.5 mm to 2 mm and more specifically is 0.7 mm to 2 mm. As noted herein these low thicknesses provide cover panel 30 with a low overall weight and flexibility suitable for cold-bending. Despite these low thicknesses, glass article 60 is also thermally strengthened to a level sufficient to provide strength and structural performance suitable for a vehicular cover panel application (e.g., break resistance, scratch resistance, dicing performance, etc.).
As shown in
The thermally strengthened glass article discussed herein may have surprisingly high surface compressive stresses, e.g., in compressive stress regions 70, 72 shown in
In various embodiments, compressive stress within compressive stress regions 70 and/or 72 are at least 60 MPa, specifically at least 68 MPa and more specifically at least 100 MPa. In various embodiments, glass article 60 having a thickness, T1, of 2 mm or less has a compressive stress of at least 80 MPa, at least 100 MPa, at least 150 MPa, at least 175 MPa, at least 200 MPa, at least 250 MPa, at least 300 MPa, at least 350 MPa, at least 400 MPa, and/or no more than 1 GPa. In contemplated embodiments, glasses having a thickness of 1.5 mm or less have a compressive stress of at least 80 MPa, at least 100 MPa, at least 150 MPa, at least 175 MPa, at least 200 MPa, at least 250 MPa, at least 300 MPa, at least 350 MPa, and/or no more than 1 GPa. In contemplated embodiments, glasses having a thickness of 1 mm or less have a compressive stress of at least 80 MPa, at least 100 MPa, at least 150 MPa, at least 175 MPa, at least 200 MPa, at least 250 MPa, at least 300 MPa, and/or no more than 1 GPa.
In some embodiments, the thermally induced central tension in interior region 74 may be greater than 40 MPa, greater than 50 MPa, greater than 75 MPa, greater than 100 MPa. In other embodiments, the thermally induced central tension in interior region 74 may be less than 300 MPa, or less than 400 MPa. In some embodiments, the thermally induced central tension in interior region 74 may be from about 50 MPa to about 300 MPa, about 60 MPa to about 200 MPa, about 70 MPa to about 150 MPa, or about 80 MPa to about 140 MPa. In various embodiments, central tension in interior region 74 is greater than 70 MPa when the thickness, T1 is 1 mm to 2 mm, is greater than 80 MPa when T1 is between 0.7 mm and 1 mm and greater than 100 MPa when T1 is 0.7 mm. These levels of central tension at these thicknesses present in the glass article discussed herein are believed to be substantially higher than previously achieved.
In various embodiments, as noted above, cover panel 30 is designed to provide for a seamless and aesthetically appealing portion of a vehicle body. In such embodiments, cover panel 30 includes one or more non-transparent layers 76. In general, non-transparent layer 76 provides for the color and/or appearance desired for the body of car 10. As shown in
Referring to
As shown in
In some such embodiments, the rate of change of the tensile stress does not exceed 7000 MPa divided by 1 mm, such as no more than 5000 MPa divided by 1 mm. In contemplated embodiments, the difference in peak values of the positive and negative tensile stresses is at least 50 MPa, such as at least 100 MPa, at least 150 MPa, at least 200 MPa, at least 250 MPa, at least 300 MPa, at least 400 MPa, at least 500 MPa, and/or no more than 50 GPa. In contemplated embodiments, glass article 60 has a peak negative tensile stress of at least 50 MPa in magnitude, such as at least 100 MPa, at least 150 MPa, at least 200 MPa, at least 250 MPa, at least 300 MPa, at least 400 MPa, at least 500 MPa. The steep tensile curve transitions are believed to be indicative of the ability to achieve higher magnitudes of negative tensile stress at a surface of a glass article for a given thickness and/or to manufacture thinner glass articles to a higher degree of negative tensile stress, such as to achieve a fragmentation potential for dicing as disclosed herein.
According to an exemplary embodiment, the high rate of change of tensile stress is at least one of the above-described magnitudes or greater sustained over a thickness-wise stretch of the stress profile 80 that is at least 2% of the thickness, such as at least 5% of the thickness, at least 10% of the thickness, at least 15% of the thickness, or at least 25% of the thickness of glass article 60. In contemplated embodiments, the strengthening extends deep into the strengthened glass article 60 such that the thickness-wise stretch with the high rate of change of tensile stress is centered at a depth of between 20% and 80% into the thickness from the first surface, which may further distinguish chemical strengthening, for example.
In various embodiments, glass article 60 is not chemically strengthened via a process such as ion exchange/implantation. In such embodiments, the ion content and chemical constituency of at least portions of compressive stress regions 70 and 72 of glass article 60, which are under the negative tensile stress, is the same as the ion content and chemical constituency of at least a portion of the interior region 74, which is under the positive tensile stress. In specific embodiments, the ion content and chemical constituency of the entire compressive stress regions 70 and 72 of glass article 60 is the same as the ion content and chemical constituency of the entire interior region 74. Additional details and methods for forming a thin, thermally strengthened glass article, such as glass article 60, can be found in U.S. Pat. No. 9,296,638, which is incorporated by reference herein in its entirety.
Aspect (1) of this disclosure pertains to a vehicle frame assembly comprising: a vehicle frame support structure having an interior surface and an exterior surface; and a cover panel coupled to the vehicle frame support structure and covering the exterior surface of the vehicle frame support structure, the cover panel comprising: a glass article comprising: a first major surface; a second major surface opposite the first major surface and separated from the first major surface by a thickness, wherein the thickness is less than or equal to 2 mm; and an interior region located between the first and second major surfaces; and wherein the glass article is thermally strengthened such that at least one of the first major surface and the second major surface is under compressive stress greater than 60 MPa; wherein the first major surface faces the exterior surface of the vehicle frame support structure.
Aspect (2) pertains to the vehicle frame assembly of Aspect (1), wherein the glass article is not chemically strengthened such that an ion content and chemical constituency of at least a portion of both the first major surface and the second major surface is the same as an ion content and chemical constituency of at least a portion of the interior region.
Aspect (3) pertains to the vehicle frame assembly of Aspect (1) or Aspect (2), further comprising a non-transparent colored layer located on the first major surface of the glass article.
Aspect (4) pertains to the vehicle frame assembly of Aspect (3), wherein the non-transparent colored layer is opaque.
Aspect (5) pertains to the vehicle frame assembly of any one of Aspects (1) through (4), further comprising an adhesive material located between the first major surface of the glass article and the exterior surface of the vehicle frame support structure, the adhesive material coupling the glass article to the vehicle frame support structure.
Aspect (6) pertains to the vehicle frame assembly of any one of Aspects (1) through (5), further comprising a panel frame, wherein: the glass article further comprises an outer edge surface extending between and surrounding the first and second major surfaces such that the outer edge surface defines a perimeter of the glass article; the panel frame comprises a first end that engages the glass article and a second end that engages the vehicle frame support structure; and the panel frame holds the glass article in place relative to the vehicle frame support structure via friction.
Aspect (7) pertains to the vehicle frame assembly of any one of Aspects (1) through (6), wherein: at least a portion of the exterior surface of the vehicle frame support structure is a curved surface comprising a first radius of curvature; the glass article is curved such that the first major surface of the glass article comprises a second radius of curvature; and the second radius of curvature substantially matches the first radius of curvature.
Aspect (8) pertains to the vehicle frame assembly of any one of Aspects (1) through (7), wherein the second major surface of the glass article defines an outermost surface of the vehicle frame assembly and includes an outer peripheral edge that is located adjacent to a vehicle window.
Aspect (9) pertains to the vehicle frame assembly of any one of Aspects (1) through (8), wherein the thickness of the glass article is 0.5 mm to 2 mm, and the compressive stress of at least one of the first major surface and the second major surface is greater than 100 MPa.
Aspect (10) pertains to the vehicle frame assembly of any one of Aspects (1) through (9), wherein the thickness of the glass article comprises an average thickness of the glass article.
Aspect (11) pertains to the vehicle frame assembly of any one of Aspects (1) through (10), wherein the thickness of the glass article comprises a maximum thickness of the glass article.
Aspect (12) pertains to a method of forming a vehicle frame assembly comprising: bending a glass article to a curved shape while a temperature of the glass article is less than a glass transition temperature of the glass article, wherein the glass article comprises: a first major surface; a second major surface opposite the first major surface and separated from the first major surface by a thickness, wherein the thickness is less than or equal to 2 mm; and an interior region located between the first and second major surfaces; and wherein the glass article is thermally strengthened such that at least one of the first major surface and the second major surface is under compressive stress greater than 60 MPa; and coupling the glass article to a vehicle frame such that the glass article is held in place relative to the vehicle frame covering a portion of the vehicle frame.
Aspect (13) pertains to the method of Aspect (12), wherein an exterior facing surface of the vehicle frame is a curved surface having a first radius of curvature, and bending further comprises bending the glass article such that the first major surface of the glass article comprises a second radius of curvature that substantially matches the first radius of curvature.
Aspect (14) pertains to the method of Aspect (12), further comprising placing an adhesive material between the first major surface of the glass article and an exterior surface of the vehicle frame, wherein coupling the glass article to a vehicle frame comprises bonding the glass article to the vehicle frame via the adhesive material.
Aspect (15) pertains to the method of any one of Aspects (12) through (14), wherein coupling the glass article to a vehicle frame comprises holding the glass article in a bent shape following bending to the vehicle frame via a panel frame that surrounds a perimeter of the glass article and that holds the glass article to the vehicle frame via a friction fit.
Aspect (16) pertains to the method of any one of Aspects (12) through (15), wherein the second major surface of the glass article defines an outermost surface of the vehicle frame assembly at the location of the portion of the vehicle frame and includes an outer peripheral edge that is located adjacent to a vehicle window.
Aspect (17) pertains to the method of Aspect (16), wherein the portion of the vehicle frame is a support pillar extending along a vertical edge of the vehicle window, wherein the glass article further comprises a peripheral edge that extends along the vertical edge of the vehicle window.
Aspect (18) pertains to the method of any one of Aspects (12) through (17), wherein the glass article is not chemically strengthened such that an ion content and chemical constituency of at least a portion of both the first major surface and the second major surface is the same as an ion content and chemical constituency of at least a portion of the interior region.
Aspect (19) pertains to the method of any one of Aspects (12) through (18), further comprising a non-transparent colored layer located on the first major surface of the glass article.
Aspect (20) pertains to the method of Aspect (19), wherein the non-transparent colored layer is opaque.
Aspect (21) pertains to the method of any one of Aspects (12) through (20), wherein the thickness of the glass article is 0.5 mm to 2 mm, and the compressive stress of at least one of the first major surface and the second major surface is greater than 100 MPa.
Aspect (22) pertains to a glass cover panel for covering a portion of a vehicle frame comprising: a glass article comprising: a first major surface; a second major surface opposite the first major surface and separated from the first major surface by a thickness, wherein the thickness is less than or equal to 2 mm; and an interior region located between the first and second major surfaces; and wherein the glass article is thermally strengthened such that at least one of the first major surface and the second major surface is under compressive stress greater than 60 MPa; wherein the glass article is not chemically strengthened such that an ion content and chemical constituency of at least a portion of both the first major surface and the second major surface is the same as an ion content and chemical constituency of at least a portion of the interior region; wherein at least a portion of the first major surface is a curved surface comprising a first radius of curvature, wherein the first radius of curvature is between 500 mm and 3000 mm; and a non-transparent colored layer located on the first major surface of the glass article.
Aspect (23) pertains to the glass cover panel of Aspect (22), wherein the non-transparent colored layer is opaque.
Aspect (24) pertains to the glass cover panel of Aspect (23), the non-transparent colored layer is at least one of an enamel frit material and an organic ink material.
Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not actually recite an order to be followed by its steps or it is not otherwise specifically stated in the claims or descriptions that the steps are to be limited to a specific order, it is in no way intended that any particular order be inferred. In addition, as used herein, the article “a” is intended to include one or more than one component or element, and is not intended to be construed as meaning only one.
It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit or scope of the disclosed embodiments. Since modifications, combinations, sub-combinations and variations of the disclosed embodiments incorporating the spirit and substance of the embodiments may occur to persons skilled in the art, the disclosed embodiments should be construed to include everything within the scope of the appended claims and their equivalents.
This application claims the benefit of priority under 35 U.S.C. § 119 of U.S. Provisional Application Ser. No. 62/643,857 filed on Mar. 16, 2018, the content of which is relied upon and incorporated herein by reference in its entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2019/022236 | 3/14/2019 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 62643857 | Mar 2018 | US |
