Patent Application
20050225161
The invention pertains to a wheel cover of metal for a wheel with a part that accommodates the tire and an inner part arranged within this part, wherein the wheel cover comprises an adapter element for fixing the wheel cover on the inner part and a cover element for at least partially covering the inner part. The invention also pertains to a method for manufacturing such a wheel cover, a cover element for at least partially covering an inner part of a wheel, particularly a wheel disk, of a vehicle, as well as a wheel with such a wheel cover.
Numerous variations of wheel covers are known from the state of the art. Most wheel covers are realized in the form of plastic parts and fixed on a wheel rim with the aid of a steel ring and plastic clips (e.g., DE 44 32 132 A1). This means that a relatively poor connection is produced between the wheel cover and the rim of the wheel. Consequently, such wheel covers are not only easily lost, but also provide no anti-theft protection at all. Due to the utilization of a plastic material, these wheel covers have an appearance with little esthetic appeal, particularly after prolonged use. When the wheel cover is clipped on the rim by means of a steel ring, the enameled surface of the rim may become scratched. In order to improve the hold on the rim and to allow a certain bracing on the rim, plastic wheel covers usually have a cambered shape that can lead to the wheel cover contacting curbstones and uneven roadways such that the wheel cover surface becomes scratched. In addition, a thusly braced wheel cover is more easily lost if a force is exerted thereupon due to the contact with a curbstones or the like.
For example, DE 198 26 060 A1 discloses devices for fixing wheel covers on a wheel for special purposes, wherein an additional central fixing device is provided for securing the wheel cover on the wheel. This wheel cover comprises a primary cover that covers the wheel disk and a disk-shaped secondary cover that covers the center of the primary cover on the outside. The central fixing device is also provided with an adapter that is fixed on at least two wheel mounting bolts and contains an inner support region that abuts the primary cover. Fixing means penetrate the primary cover and connect the secondary cover to the adapter in such a way that the primary cover is held between the support region of a cap and the secondary cover. The different layers of the adapter and the primary cover are firmly held on one another due to the central fixing device. The adapter contains a sleeve-shaped section that bridges the space between the wheel disk and the primary cover. The auxiliary cover is fixed on the adapter by means of snap-in devices formed by elevations and depressions on lugs and hammerheads of the adapter and the secondary cover.
A special method for securing a hubcap is described in WO 03/080367 A1. In this case, a plurality of tubular extensions or cylindrical sleeves is provided for accommodating wheel screws that serve for fixing the cap on the wheel. A special element restricts the axial adjustment of the screws to only two positions, wherein the screws can only be completely removed with a special tool in order to provide a corresponding anti-theft protection.
DE 37 40 909 A1 discloses a screw-mounted hubcap, particularly for a motor bus, that is provided with a lock and holding bars. This hubcap holding arrangement is firmly placed against the walls of the rim flange groove in an open groove between the rim well and the rim flange of the wheel rim. DE 38 35 004 C2 also discloses a hubcap of light metal that is provided with a lock.
Metal-plated hubcaps of plastic with a shape that follows the outside contour of the wheel are disclosed in DE 43 21 057 A1 and DE 102 04 394 A1. These hubcaps are respectively fixed on a wheel with the aid of clipping or bonding means and provided with a cap for covering the wheel hub.
A wheel covering device of transparent plastic is disclosed in DE 101 45 085 A1. Since a transparent plastic is used, the light metal rim is still visible despite the protective covering device. A fixing element for fixing the covering device on the wheel has a barb-like shape and/or is provided with a predetermined breaking point in order to realize an anti-theft protection. Other wheel covers of metallic or non-metallic material with clamping elements integrally formed onto their periphery are disclosed in DE 39 01 542 A1.
DE 695 24 085 T2 discloses a wheel cover retaining system, in which a wheel cover is provided with a plurality of pockets and wheel nuts for securing the wheel and the wheel cover on a vehicle are arranged in the pockets.
An annular wheel cover of special steel, aluminum or plastic is known from DE 44 32 132 A1. The special steel covers and aluminum covers consist of drawn parts or deep-drawn parts or turned parts. This publication proposes to utilize clips or a combination of screws and bores for connecting the wheel cover to the wheel.
In addition to the conventional deep-drawing or casting methods employed in the manufacture of wheel covers, DE 34 33 185 C2 discloses a method for manufacturing a hubcap of light metal with a sharp-edged, right-angled border, wherein the material thickness of the border is greater than that of the cover disk, and wherein the hubcap consists of a high-grade aluminum sheet and is manufactured in a non-cutting fashion. The hubcap is produced by means of pressing in a pressing tool, wherein the free edge of a round sheet metal disk is initially doubled over by a small angle with the aid of an axially displaceable pressing roller and subsequently compressed into a step formed on the periphery of the chuck by means of a radially displaceable roller tool.
If a wheel cover is provided with clips that engage into the rim, one has to accept the above-described risks of possibly damaging the rim surface or the part accommodating the tire and of easily losing the wheel cover. The installation of the other above-described type of wheel covers that are secured against fast access by means of locks is relatively complicated. A combination of a primary cover, a secondary cover and an adapter in accordance with DE 198 26 060 A1 requires a particularly high installation expenditure, namely because the individual parts need to be installed successively and fixed in an interlocking fashion.
The present invention is based on the objective of disclosing a wheel cover of metal for a wheel with a part that accommodates the tire and an inner part arranged within this part, wherein this wheel cover comprises an adapter element for fixing the wheel cover on the inner part and a cover element for at least partially covering the inner part, and wherein said wheel cover eliminates the above-described disadvantages due to the fact that it can be easily installed while simultaneously protecting the wheel cover from being lost or stolen. With respect to a cover element for at least partially covering the inner part of a wheel, the objective of the invention consists of achieving a high-quality external appearance.
This objective is attained with a wheel cover according to the preamble of claim 1 in that the adapter element is inseparably fixed on the cover element. With respect to a method for manufacturing a wheel cover according to the preamble of claim 13, the objective of the invention is attained with the following steps: producing a sheet metal blank with a predetermined contour, forming the sheet metal blank into a cover element by means of hydroforming and connecting a preformed adapter element to the cover element such that a wheel cover is obtained. With respect to an adapter element according to the preamble of claim 17, the objective of the invention is attained in that the cover element is manufactured by means of hydroforming. Additional developments of the invention are defined in the dependent claims.
The invention proposes a wheel cover that can be directly installed on the part accommodating a tire, particularly a rim, in the form of a single part. It is no longer required to install and interlock several different parts as it is the case, for example, with the method disclosed in DE 198 26 060 A1. In addition, the customary attachment of hubcaps with clips in accordance with the state of the part is also eliminated, wherein this clip-type attachment may lead to the entire wheel cover falling off the wheel as the clamping force of the hubcap and the adapter diminishes, particularly in a hubcap according to DE 198 26 060 A1. The adapter element according to the invention makes it possible to adequately and securely fix the compact wheel cover comprising the adapter element and the cover element on a wheel. The adapter element forms a stable abutment for fixing the wheel cover by means of wheel screws or wheel mounting bolts. In addition, the rigid connection between the adapter element and the cover element secures the wheel cover from being lost, particularly at high vehicle speeds and on uneven roadways, as well as from being stolen, namely without having to provide a lock on the wheel cover. It is advantageous that the adapter element can be simultaneously used for centering the wheel cover relative to the wheel, i.e., for aligning the center of the wheel and the center of the wheel cover relative to one another.
When producing the cover element by means of hydroforming, hydrostatic pressure is exerted upon the sheet metal of the cover element and an exertion of mechanical pressure is prevented. The damages to the surface structure of the wheel cover that regularly occur in the state of the art can be advantageously prevented in this fashion. If the wheel cover surface is damaged during the course of the manufacturing process, its repair not only is almost impossible, but also extremely costly. Surface damages do not occur in hydroforming processes because only the rear side of the cover element is contacted by a die while the front side of the cover element is deformed against the pressure of an active medium. Possible scratches or tool marks on the rear side of the cover element are no longer visible once the wheel cover is installed on the wheel disk. In deep-drawing and pressing methods, for example, in accordance with DE 34 33 185 C2, a texture is produced on both sides of the sheet metal by the forming tool. This leads to a reduced quality of the formed object. When utilizing a hydroforming method, it is also possible to achieve a more favorable drawing ratio β for the sheet metal that may be as high as 2.6 or similar values.
In order to fix the wheel cover on a wheel by means of wheel screws or wheel mounting bolts, the adapter element and the cover element preferably contain through-openings for inserting the wheel screws and/or wheel mounting bolts. The number of through-opening depends on the number of wheel screws or wheel mounting bolts on the respective wheel. For example, three, four, five or six through-openings may be provided. The dimensions of the openings are advantageously adapted to one another and to openings in the inner part of the wheel, particularly a wheel disk, such that the wheel cover is able to optimally cover webs and openings or recesses in the inner part and the wheel disk, respectively. For example, a cast aluminum wheel can be covered in order to conceal the simple, non-finished surface of the cast part with the optically appealing surface of the wheel cover or the cover element, respectively.
The through-openings of the adapter element are preferably arranged radially around the central cambered region. After the installation on the cover element, this cambered region is able to engage into a central opening in the cover element and support itself therein. The through-openings in the cover element are preferably also arranged radially around its center. The through-openings in the adapter element and in the cover element are advantageously adapted to one another with respect to their position and spacing so as to prevent the wheel screws or wheel mounting bolts from jamming.
At least one of the through-openings is preferably realized larger than the other through-openings. The dimensions of the largest opening are preferably chosen such that the head and the collar of a wheel screw or wheel nut fit through the opening. The adjustment of the wheel cover on the wheel is simplified by providing a larger or largest opening. This also makes it possible to push the larger through-opening over a first installed wheel screw or wheel nut and to fix the wheel cover on the wheel. The wheel cover is then properly fixed on the wheel with the remaining wheel mounting bolts, wheel nuts and/or wheel screws that are inserted into the smaller through-openings in the adapter element and thusly fix the adapter element on the inner part of the wheel. A wheel can be initially installed on a vehicle without the wheel cover, in which case the wheel cover is subsequently fixed on the wheel. This makes it possible to prevent damages to the surface of the wheel cover and the cover element, respectively, during the initial installation. In addition, the installer is able to initially install the wheel and then fix the wheel cover on the wheel without requiring a “third hand” as it is frequently the case with wheel covers according to the state of the art.
The adapter element and/or the cover element preferably contains an opening for a valve to be inserted into the rim. In this respect, it is particularly preferred to arrange the opening for a valve to be inserted into the rim opposite of the largest opening in the adapter element and/or the cover element. This makes it possible to still adjust the wheel cover and to achieve a defined fit thereof on the wheel.
Openings or recesses are preferably positioned in the wheel cover such that they are essentially aligned in with openings or recesses in the wheel disk after the wheel cover is installed. Such openings or recesses are provided in the inner part of the wheel, for example, in order to ventilate the brake disks and partly realized in an optically appealing fashion. This design can also be utilized for the wheel cover in order to create the impression of directly looking at the inner part of the wheel. However, the wheel cover also serves for protecting the inner part of the wheel from external damages.
The central region of the cover element preferably contains a depression and/or a recess for inserting a decorative element. The cambered region of the adapter element is advantageously arranged on the rear side of such a recess. This means that the decorative element is secondarily or primarily fixed on the adapter element. A decorative element specified by the customer preferably is or can be fixed in the center of the wheel cover. Such a decorative element may consist of a decorative cap or a plaque that carries the emblem of the respective automobile, on which the wheel cover is installed. The decorative element may be fixed in the depression or recess by means of a plug-type connection, bonding, soldering, clips, at least one mounting element, particularly a screw, a clinch bolt or similar fixing arrangements. At least the rear side of the decorative element contains a pin or a similar element that can be inserted or wedged into an opening in the cover element. It would also be conceivable to bond, solder or weld the decorative element on the cover element.
It is preferred that at least the cover element of the wheel cover consists of steel, particularly special steel. It is particularly preferred that both the cover element and the adapter element consist of steel or special steel. This makes it possible to achieve a particularly appealing and high-quality optical appearance as well as a superior stability of the wheel cover. If the wheel cover according to the present invention is used on vehicles with steel rims, the optical appearance of said steel rims can be advantageously improved. It is common practice to forgo the purchase of separate light metal rims for winter tires, and the refitting of these tires on the rims for the summer tires is unfeasible due to the associated costs. In such instances, the optical appearance of winter tires fitted on steel rims can be improved with the wheel cover according to the present invention. This applies analogously to aluminum rims that have been damaged, i.e., scratched or otherwise adversely affected.
In order to additionally improve the external appearance of the wheel cover, it may be provided with one or more different surface structures. In this context, it would be possible, in particular, to at least partially polish, brush, frost or otherwise structure the surface of the wheel cover. This means that effects provided on light metal or aluminum rims can also be reproduced on the wheel cover.
In the method according to the invention for manufacturing cover elements according to the invention for the wheel covers, the form cover element is preferably cut to size, particularly punched, along the edges and/or surface area. Due to this measure, the openings provided in the inner part of the wheel may also be arranged in the wheel cover such that they can be covered therewith. The peripheral edges of the cut-to-size cover element are then preferably smoothed (rounded). This is achieved, in particular, by beading the peripheral edges. This eliminates the risk of being injured by these sharp edges and improves the optical appearance of the peripheral edges.
The adapter element is preferably mounted centrally on the formed and cut cover element, particularly by means of one or more soldering or welding spots. In this case, a positive connection is produced, particularly by means of rivets, clinching or penetration joining, particularly machine riveting. The central region of the cover element can be covered with the decorative element as described above in order to conceal the mounting points. The connection between the adapter element and the cover element in the center of the cover element also ensures that these two elements are rigidly held together, namely because the wheel cover is fixed on the wheel around this region and the center consequently is subjected to only slight tensions. It is preferred that the wheel cover can be fixed or installed on the wheel with a prestress, wherein the wheel cover at least partially adjoins the wheel in an edge region (rim flange). It is preferred to arrange the wheel cover such that its periphery has a certain clearance referred to the outer edge of the wheel, wherein the prestress is generated by fixing the wheel cover on the wheel with the aid of the wheel mounting bolts or wheel screws. The aforementioned clearance represents a constructive prerequisite that ensures a calculable prestress in order to prevent the wheel cover from being unintentionally bent during the installation. The clearance may amount, for example, to 3 mm. Fluttering of the wheel cover relative to the wheel can also be advantageously prevented by generating such a prestress.
The invention is described in greater detail below with reference to one embodiment that is illustrated in the figures. The figures show:
a and 4b a schematic diagram of the hydroforming process for producing a wheel cover according to the invention.
The exploded view according to
The largest through-opening 221 is arranged opposite of an opening 32 in the edge region 33 of the cover element 30 that serves for leading through a (not-shown) valve to be inserted into the rim 42 of the wheel 40. This makes it possible to always position the wheel cover on a wheel in a precisely fitted fashion.
The cover element is manufactured by means of hydroforming as described below with reference to
The wheel cover is positioned such that its periphery is radially spaced apart from the rim flange 44 of the wheel 40. This makes it possible to prestress the wheel cover relative to the rim 42 after the wheel mounting bolts 50 are tightened. This reliably prevents the simple detachment of the wheel cover and not only secures the wheel cover from being lost, but also from being stolen. The prestress also makes it possible to prevent fluttering of the wheel cover while driving.
a and 4b show a schematic diagram for elucidating the production of the cover element 30 by means of hydroforming. In this case, a sheet metal blank 39 with a certain contour is initially cut or punched out of a corresponding sheet. The contour is advantageously adapted to that of the finished cover element in order to maintain the trimming work after the forming process at a minimum. The sheet metal blank may be provided with different surface structures, for example, treated by means of polishing, brushing, frosting or another surface treatment method. The sheet metal blank is inserted into the hydraulic press 60. The hydraulic press comprises an upper punch 61 and holding-down appliances 62 that form part of an upper die 63, as well as a lower die 64. The lower die is provided with a supply line 65 for an active medium 66 and with an active medium container 67.
After inserting the sheet metal blank 38 into the hydraulic press, the holding-down appliances 62 are lowered (arrows 70) such that the sheet metal blank is fixed in position within the press. In addition, the edge region of the sheet metal blank held by the holding-down appliances is rendered fluid-tight by means of a draw die 68. Subsequently, the active medium 66 is pumped into the active medium container 67 via the supply line 65 (arrow 71), and the bottom of the sheet metal blank 38 is subjected to pressure (arrows 72) such that it is pre-cambered opposite to the forming direction. The ram 61 is not yet lowered on the sheet metal blank in this step.
Once the preforming process is completed, the ram 61 is lowered (arrows 73) as shown in
The cover element preferably consists of metal, particularly steel or special steel. The adapter element preferably also consists of steel or special steel such that both elements can be easily connected without the risk of the respective surfaces attacking one another, e.g., due to contact corrosion. The adapter element can be produced by means of deep-drawing or a corresponding method. Since the adapter element is not externally visible, scratches or other possible surface damages do not cause any problems with respect to the optical quality control. It would also be conceivable, in principle, to shape the adapter element by means of hydroforming.
In addition to the embodiments of wheel covers that were described above and are illustrated in the figures, the invention also makes it possible to realize numerous other embodiments, in which an adapter element is rigidly or inseparably connected to a cover element of the wheel cover and/or a cover element for at least partially covering the inner part of a wheel is produced by means of hydroforming. The cover element may have any arbitrary shape and size such it can be adapted to the respective part of the wheel, particularly the wheel disk on which it should be installed, analogous to the adapter element. It is possible to provide a plurality of different adapter elements and only a few different types of cover elements. In this case, an adaptation to different lateral shapes of wheels can be achieved with the different adapter elements.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2004 017 554.3 | Apr 2004 | DE | national |
