Patent ID: 12240527

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding introduction, summary, or the following detailed description. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.

As used herein, the term “vehicle” is not limited to automobiles. While the present technology is described primarily herein in connection with automobiles, the technology is not limited to automobiles. The concepts can be used in a wide variety of applications, such as in connection with motorcycles, mopeds, locomotives, aircraft, marine craft, and other vehicles, or other structural or non-structural applications where it may be desirable to deposit a polymer resin in passageways formed in components.

The present disclosure is directed to structural components including structural reinforcements, inflatable-based systems for forming structural reinforcements within structural components, and an inflatable-based process for controlling structural foam reinforcement molding. Structural components include components that perform at least one of the following functions: support vehicle weight, absorb road shock, and manage collision energy. A structural reinforcement is understood herein as material that improves a mechanical property of the structural component, such as a compression strength, flexural strength, tensile strength, or energy absorption capacity of the structural component.

FIG.1Aillustrates a vehicle100including a body frame102, the body frame102includes several structural components103, such as the A-pillar104and the B-pillar106.FIGS.1B and1Cillustrate a B-pillar106. The structural components103are formed from components112that include hollow passages. For example, the B-pillar106is formed from a component112, which includes an interior surface114that defines a first hollow passage116within the component112. The first hollow passage116is an elongate hollow passage. The structural reinforcements120,122,124,126contact the interior surface114of the component112, and are formed at different, discrete locations within the first hollow passage116of the component112. In addition, the structural reinforcements120,122,124,126are formed of polymer resin foam, which exhibits a cellular structure. As illustrated, four structural reinforcements are provided; however, it should be appreciated one or more structural reinforcements may be provided for a single structural component103, such as between one and ten structural reinforcements. In addition, where multiple structural reinforcements may be present, the structural reinforcements may be made from a variety of materials, having varying compositions, physical properties, and mechanical properties.

The structural reinforcements120,122,124,126only partially fill a given cross-section of the first hollow passage116of the component112and do not fill the entire cross-section of the first hollow passage116. As illustrated inFIG.1C, the structural reinforcement122fills a portion of the cross-section of the first hollow passage116and the structural reinforcement is hollow, defining a second hollow passage130. In other aspects, the structural reinforcement122fills a portion of the cross-section of the first hollow passage116and a second hollow passage130is defined by both the structural reinforcement122and the component112. In aspects, the structural reinforcement122occludes in the range of 5 percent to 90 percent, including all values and ranges therein, of a given cross-section of the first hollow passage116. Partial filling of the component112with the structural reinforcements reduces the weight of the structural components103as compared to fully filling the structural component103with the structural reinforcement11, contributing to a reduction in weight of the entire vehicle100.

A process200for molding the structural reinforcements120,122,124,126within a structural component103is illustrated inFIG.2, with reference toFIGS.3A through3E, which illustrate a system for foaming a structural component103for a vehicle. The process200begins at block202by inserting an uninflated, insertable bladder into a first hollow passage303defined by the interior surfaces305of the component304of a structural component300. The uninflated bladder302includes guide wires306,308connected to the bladder302and extending from either side of the bladder302to assist in positioning the bladder302within the component304. The guide wires306,308also include attachment loops310,312for securing the bladder302in place to prevent movement of the bladder302in the component304during the molding process. The attachment loops310,312may be connected to the structural component300or to a fixture retaining the structural component300in place during the molding process. In aspects, the bladder302is formed from silicone, polypropylene, polyamide-reinforced polypropylene, or rubber. In additional aspects, the bladder302is coated with a mold-release compound or otherwise treated to prevent or at least reduce adhesion to the polymer resin foam.

The bladder302further includes restricted portions,314,316,318, which exhibit less expansion than the remainder of the bladder302when the bladder302is inflated. The restricted portions314,316,318may be formed by winding thread, wire, bands, or elastic around the bladder302or by forming the restricted portions314,316,318of the bladder302with one or more different materials that exhibit different degrees of extensibility or deformation when a force is applied against the bladder302by the fluid320inflating the bladder302. In addition, localized constraints, such as seams, tethers, and other stitching may also influence the inflated shape of the bladder302and provided restricted portions constraining expansion of the bladder302. By altering the number or locations of the windings or by using different materials, different geometries of the bladder302and structural reinforcements120,122,124,126may be formed. Thus, while three restricted portions are illustrated, any number of restricted portions may be provided, such as one restricted portion up to ten restricted portions. Further, it should be appreciated that while restricted portions are illustrates as extending around the entire periphery of the bladder302, the restriction portions may be limited to segments of the bladder periphery.

In addition to restricted portions, expendable portions may also be provided, and reference is made toFIG.4, which illustrates a bladder302that includes restricted portions314,316and expandable portions328. As noted above, the restricted portions314,316,318restrict the degree to which the bladder302may inflate in given regions relative to the other portions of the bladder302. The expandable portions328expand to a greater degree relative to other portions of the bladder302when the bladder is inflated. The expandable portions328exhibit different deformation characteristics, i.e., greater deformation and greater extensibility, than the remaining portions of the bladder302when the bladder302is filled with a fluid. These expandable portions328of the bladder302are formed by altering the materials or the thickness of the wall sections. When inflated, the portions328produces lobes327extending from the primary body329of the bladder302illustrated inFIG.5, which is a cross-section of the inflated bladder302within a component304. In the illustrated aspect, the lobes327locate the bladder302within the first hollow passage303and hold the bladder302in place within the first hollow passage303of the component304. The combination of the restricted portions314,316,318and expandable portions328may be arranged and adjusted to form any number of geometries when the bladder302is inflated. Thus, while four lobes327are illustrated, any number of lobes327may be provided.

At block204, and with reference toFIG.3B, the bladder302is inflated to a given pressure by filling the bladder302with a fluid320, such as air, an inert gas, or a liquid, through a supply line322connected to the interior323of the bladder302. The bladder302contacts and impinges on the interior surface324of the component304and forms a seal with the interior surface324of the component304to define a plurality of cavities330,334,336between the interior surface305of the component304and the bladder302. It should be appreciated that while multiple cavities are illustrated one cavity or two or more cavities may be defined. In aspects, the temperature of the fluid320may be regulated, such as by circulating the fluid through a chiller or a heater, to facilitate the molding of the structural reinforcements through assisting in curing or cooling the resin later introduced into cavities330,332,334. In aspects, the inflation pressure in the bladder302is modulated to modulate the shape of the bladder302. Modulation may occur while the cavities330,332,334are being filled with the polymer resin or while foaming the polymer resin foam348.

After filling the bladder302at block204, at block208the cavities330,332,334are filled with a polymer resin forming the polymer resin foam348, which creates the structural reinforcements342,344,346. In aspects, the polymer resin evolves gas to form a polymer resin foam348through a chemical reaction, or the polymer resin includes blowing agents or expandable particles in the polymer resin. In aspects, the foaming may be triggered upon heating the polymer resin. Examples of polymer resin foams348include, for example, one-part or two-part foams, thermoplastic materials that include expandable particles or blowing agents, or thermoplastic materials that are mixed with a gas after melting and prior to molding. Polymer resins used to form polymer resin foams348include, e.g., one or more of: polyurethane, epoxy, polyisocyanurate, ethylene vinyl acetate, polyolefin, polyolefin-ethylene vinyl acetate blends, polybutylene terephthalate, polycarbonate, polyphenylene oxide, polyethylene terephthalate, and acrylonitrile butadiene styrene. As noted above, more than one polymer resin foam348may be used when a given structural component300includes multiple structural reinforcements342,344,346. Different polymer resins may be used to form the polymer resin foam348of each structural reinforcement or the same polymer resin with different amounts of foaming agent may be used. The different polymer resin foams348may exhibit different densities or different mechanical properties including compression strength and tensile strength. In additional or alternative aspects, different amounts of polymer resin may be injected into a given cavity to provide polymer resin foams of different densities.

The polymer resin forming the polymer resin foam348is introduced by a runner system352. In aspects, the runner system352is formed in one or more fixtures354the component304is retained against. In other aspects, the runner system352is formed from tubing that is connectable to the component304. The component304defines a number of ports356,358,360connected to the cavities330,332,334and connectable to the runner system352for introducing the polymer resin of the polymer resin foam348into cavities330,332,334, before or after foaming the polymer resin. Further, the runner system352is connected to a polymer resin supply362. In aspects, the polymer resin supply362includes one or more of the following: supply drums, accumulators, metering pumps, feeders, extruders, and mixers. In aspects, each port356,358,360is connected to its own runner system352, which is in turn connected to its own polymer resin supply362and each polymer resin supply362is individually metered to allow a different amount of precursor to be injected into each site. This allows control over the density of the polymer resin foam348in each cavity330,332,334. Further, vents366,368,370are defined in component304and connected to the cavities330,332,334to vent air out of the cavities330,332,334as the polymer resin of the polymer resin foam348is being injected into the cavities330,332,334.

In optional aspects, prior to filling the cavities330,332,334at block208, at block206the polymer resin is melted, multiple components of the polymer resin is mixed, or the resin is combined with a gas. For example, when a thermoplastic resin is used, the polymer resin is melted through the application of heat and, in some aspects, combined with gas. In another example, when a two-component resin, such as polyurethane or epoxy, is used, the resin components are mixed. Or, in alternative aspects, the polymer resin is introduced without pre-treatment such as melting, mixing, or combining with a gas, such as in the case of a one-part polyurethane.

After filling the cavities330,332,334with the polymer resin of the polymer resin foam348at block208, the polymer resin is crosslinked or solidified in the cavities330,332,334. For example, where the polymer resin is a two-component mixture, the polymer resin may form cross-links and solidify into the polymer resin foam348. In other examples, the polymer resin is heated to initiate cross-linking, or kick-off a blowing agent in a polymer resin in a melt state or expand expandable particles in the polymer resin in a melt state, to cause the evolution or expansion of gasses, forming the polymer resin foam348. When the polymer resin of the polymer resin foam348is provided as a melt, the foamed polymer resin may cool and solidify. It should be appreciated that the polymer resin does not need to be completely crosslinked or completely cooled to ambient temperature but crosslinked sufficiently or cooled sufficiently so that the structural reinforcements342,344,346resist deformation upon removal of the bladder302.

With reference toFIGS.3D and3E, once the polymer resin foam348is sufficiently solidified at block210, at block212the bladder302is deflated and at block214the bladder is removed from the structural reinforcement342,344,346. In aspects, the bladder302may be deflated by pumping the liquid out of the bladder302or by simply reducing the pressure applied to the fluid320in the bladder302by the elastic recovery of the bladder302or an external source. The structural component300is formed from the component304and the structural reinforcements342,344,346. As illustrated, the structural reinforcements120,122,124,126,342,344,346assume a variety of shapes depending on the shape of the component112,304and the bladder302.

The inclusion of the structural reinforcements120,122,124,126,342,344,346in the structural components300provides an increase in mechanical characteristics. An illustrative example is provided inFIGS.6through9C, which is exemplary in nature and not meant to limit the scope of the present disclosure.FIG.6includes a graph illustrating the effect of a hollow structural component700versus structural components800,900including structural reinforcements804,904. The structural components700,800,900are elongate pipes and are formed from polyetherimide (ULTEM 9085 available from SABIC, Houston, TX) using an FDM 3D printer exhibiting a wall thickness of 1 mm. Within the structural component800is provided a structural reinforcement formed from 3 lb/ft3(pounds per cubic foot) density polyurethane foam, extending along the length of the structural component800and having a foam thickness of 10 mm. Within the structural component900is provided a structural reinforcement formed from 10 lb/ft3density polyurethane foam, extending along the length of the structural component900having a thickness of 10 mm.FIGS.7A,8A and9Aillustrate the circularity of the structural components700,800,900prior to testing.

A force was provided on the structural components700,800,900using an Instron three-point bending frame. The structural components were fixed at two roller supports and indented by 30 Kilonewton (kN) load cell, which measured the deflection from the top surface. An extensometer was placed under the component to measure the deflection from the bottom. The force was applied at a rate of 3 millimeters per minute. As illustrated in the graph, the amount of force to cause the structural component700without a structural reinforcement to deform, plot line710was lower than the amount of force to cause the structural components800,900including structural reinforcements804,904to deform, plot lines810,910, respectively.FIGS.7B,8B, and9Billustrate the pinching of the structural components700,800,900, and loss of circularity, at failure. As illustrated,FIGS.7C,8C and9Cillustrate a top view of the resultant deformation712,812,912of in the structural components700,800,900at failure.

While the process described herein is described with relation to automotive structural members, it should be appreciated that the process may be used to incorporate structural reinforcements in other structural components that include or define hollow passages. Structural components include components that perform at least one of the following functions: support vehicle weight, absorb road shock, and manage collision energy. Structural components include, e.g., the various pillars (A, B, C, D) as noted above, radiator core support, front and rear bumper reinforcements, cross-members, seat frames, front, and rear door intrusion beams, etc. Further, it should be appreciated that the method used herein may be used for depositing other materials in hollow passages defined by other vehicle components, such as noise deadening material within air ducts.

The structural components including the structural reinforcements and method of forming the structural components including the structural reinforcements offer several advantages. As compared to molding methods that require free-rise and complete fill of the structural reinforcement in the structural component, the advantages include, for example, the ability to form multiple structural reinforcements in the structural component at a single time. This results in a reduction in cycle time to form a structural component including more multiple structural reinforcements, requiring multiple filling stations. Advantages further includes a reduction in weight due to the ability to partially fill of the structural reinforcement in the structural component. This results in a reduction in weight of the structural component, contributing to weight reductions in the vehicle.

The description of the present disclosure is merely exemplary in nature and variations that do not depart from the gist of the present disclosure are intended to be within the scope of the present disclosure. Such variations are not to be regarded as a departure from the spirit and scope of the present disclosure.