DE102011077834A1 - Method for manufacturing wheel of passenger car, involves closing injection molding tool after insertion of fiber-reinforced plastic into mold cavities of injection molding tool, where semi-finished product is embedded in mold cavities - Google Patents

Abstract

The method involves performing an injection molding of a fiber-reinforced plastic i.e. polyamide, into a semi-finished product that is inserted into mold cavities of an injection molding tool to produce a fiber-composite structural component. The semi-finished product is comprised of a long fiber in a form a semi-finished band (5) for a reinforcement of an annular portion i.e. rim (1), and individual radial sections i.e. spokes (2). The injection molding tool is closed after insertion of the fiber-reinforced plastic, where the semi-finished product is embedded in the mold cavities.

Description

The invention relates to a method for producing a fiber composite structural part, which consists of an annular portion and a plurality of radial sections supported thereon and supported by injection molding or injection molding of fiber-reinforced plastic using prefabricated and in the mold cavity of an injection mold Semi-finished product is produced. Specifically, the fiber composite structural member is a wheel constituted by a rim as the above-mentioned annular portion, spokes as radial portions, and a hub portion of a motor vehicle, and in this respect, the technical environment is exemplified DE 42 02 287 A1 directed.

Vehicle wheels should be known to have the lowest possible weight, which is why, in addition to suitable light metal alloys, a fiber-reinforced plastic material would be a preferred material. However, the forces that can act on a vehicle wheel, in particular such a motor vehicle, immense, which is why special measures to ensure the required strength are provided on a wheel made of plastic.

In this respect, a measure to indicate the object of the present invention, wherein the fundamental principle according to the invention on any fiber composite structural parts, which are constructed in the broadest sense similar to a vehicle wheel, namely consist of an annular portion and a plurality of these supporting or supported on this radial sections , is simply transferable, which is why in the present case in general form a manufacturing process for such a corresponding fiber composite structural part is claimed.

The solution of the above object is for a manufacturing method according to the preamble of claim 1, characterized in that the shaped in the form of a band and long fibers containing semi-finished not only to reinforce the annular portion, but also the individual radial sections in each case annular in the injection molding tool is inserted, after which the tool is closed and in the mold cavity, the substantially short fibers containing plastic material is injected, whereby the band-shaped semifinished product is embedded therein. Preferably, the band-shaped semi-finished product contains substantially so-called. Endless fibers, which extend uninterruptedly through the entire semi-finished strip between its two ends.

Proposed is the use of a band-shaped or ribbon-like semi-finished product, which is inserted into the injection mold and preferably in the mold cavity of the sub-tool before the tool is closed, d. H. the upper tool is placed on the lower tool, after which in the mold cavity of the tool which is also provided with fibers liquid and tool-hardening plastic material is injected. It should be expressly mentioned that by the terms used "upper tool" and "sub-tool" by no means the location of these tool parts to be described in space, but only the fact that it is a multi-part tool, which is a has mold cavity accessible by opening the upper tool.

According to the invention are in the ribbon-like semi-finished, also called semi-finished strip, substantially longer fibers with a length of at least several centimeters and preferably so-called. Endless fibers which extend substantially over the entire length of the strip material used. Due to this feature, the semi-finished strip is extremely high load capacity and thus can transmit high forces in the final state of the structural part or wheel. Preferably, for this purpose, the semi-finished strip is repeatedly annular (so that a plurality of juxtaposed or superimposed rings are formed) in the tool and preferably the semi-finished strip is at least slightly biased inserted into the tool before the plastic material is injected into the mold cavity. The said tension can simply be introduced into the semi-finished strip in that this strip is guided or wound around so-called clamping elements with the application of a small clamping force. At least for the annular portion of the structural member, core parts or support cores of the tool forming for that annular structural member portion may form the respective clamping members for the semifinished product tape. For the formation of said radial sections of the structural part, however, can be provided in the end portions of pin-like clamping elements or the like in the tool, around which the band-shaped semi-finished simply or repeatedly guided or wound. So that the tension applied during insertion or winding of the semifinished product strip is retained in the strip, the end of the strip can be stapled or glued or otherwise suitably fastened.

In the case of a vehicle wheel as a fiber composite structure part is then not only in the rim of the wheel, a semi-finished tape preferably wound several times in multiple layers and depending on the width several times side by side in the circumferential direction of the rim provided, which is guided in accordance with the rim shape corresponding to corresponding provided in the mold cavity support cores or the like, but it also contains each wheel spoke for a ring guided by suitable elements or wound semi-finished band. Preferably, such a pin-like element functioning as a tensioner for the semifinished product strip is provided in each end section of a spoke, which is also referred to as a tensioning element.

Preferably, each pin-like clamping element is aligned in such a way that the semi-finished strip can be performed well around this, that is parallel to the surface of the strip and perpendicular to the longitudinal extent of the strip. Thus, the clamping elements may be aligned substantially parallel to the axis of rotation of the finished wheel, wherein in any case the clamping element lying close to the wheel center can also be formed by that core in the tool, which is to represent a hole for one of the wheel bolts with which the wheel the hub of a wheel carrier or the like is attached, is provided.

On a vehicle wheel as a fiber composite structural part to be produced according to the invention, the hub part of the wheel can otherwise be formed similarly to the spokes, namely by winding a band-shaped semi-finished product around pin-shaped clamping elements provided in the mold cavity. Again, the clamping elements can simultaneously form the tool cores for the holes for the wheel bolts in the wheel. Optionally, however, it is not necessary to reinforce the hub part by a semi-finished strip, since at least in the quasi within the holes for the wheel bolts hub portion of the wheel only small forces are effective.

It can not only be provided in the sub-tool in which the semi-finished strip is inserted, for the latter said clamping elements, but it can also be provided in the upper tool corresponding clamping elements, the closing of the injection mold on the in the sub Tool clamping elements impinge. For a secure position of the semi-finished strip is preferably ensured under tension in the tool even when injecting the liquid plastic material. It can be provided that the clamping elements of the sub-tool are at least slightly displaced into the lower tool by the impinging clamping elements of the upper tool. Moreover, in the case of a tool for the production of a vehicle wheel according to the invention, the closing direction or opening direction of the tool usually corresponds to the direction of the wheel rotation axis, i. H. essentially in the direction of the wheel rotation axis, the upper tool is placed on the sub-tool when the mold cavity is to be closed.

In the closed tool, more precisely in the mold cavity can then (after inserting the semi-finished strip) to form the fiber composite structural part, the liquid plastic material with the therein substantially short fibers (the fiber length may, for example, in the order of 3 to 20 mm) to be subsequently cured. This liquid plastic material may be a thermoplastic material or a recyclate thereof, for example polyamide, but also a duroplastic (for example polyurethane, epoxy resin). Possible fibers include carbon fibers, but also glass fibers, metal fibers or textile fibers or a mix of different types of fibers. In particular with textile fibers, a low impact sensitivity of a vehicle wheel (as a fiber composite structural part produced according to the invention) could be represented with regard to possible curb contacts.

The attached 1 and 2 show a vehicle wheel produced according to the invention in a perspective view ( 1 ) or in half section ( 2 ), taking off 2 the position of the semi-finished strip shows particularly well while in 1 the wheel-spoke reinforcing semi-finished bands are shown only dashed, since they are of course not visible in such a view of a finished wheel. 3 finally shows only principled and highly abstracted the supervision in the mold cavity of the open sub-tool, with which in cooperation with a corresponding upper tool, not shown, a plastic wheel can be produced by the method according to the invention, wherein in the sub-tool a semi-finished Band is inserted to reinforce the rim and spokes.

First up 1 With reference to FIG. 1, it can be seen that a wheel of a motor vehicle, for example a passenger car, consisting of a rim, which is constructed as usual in the external design 1 , several spokes 2 and a hub part 3 , Holes for receiving the wheel bolts are indicated by the reference numeral 4 characterized. This wheel is made entirely in fiber-reinforced plastic material according to the method of the invention. As a result, not only is in the rim 1 not shown semifinished tape, but it is also every spoke 2 by embedded annular semi-finished band 5 , the dashed - because actually not visible - is shown, reinforced.

2 shows with a radial section plane a half section through this vehicle wheel. In the rim 1 are several juxtaposed and also partially overlapping layers of semi-finished band 5 intended. For example, with a rim width of 19 cm and a width of the semi-finished strip 5 of 3 cm between the two rim flanges seven adjacent layers of semi-finished band 5 be provided. Any such "location" of semi-finished tape 5 can be made of multi-layer semi-finished tape 5 be constructed by - as indicated by 3 will be explained - the semi-finished band 5 several times around so-called. Support cores, which the wheel center point M facing contour of the rim 1 determine is placed in the circumferential direction of the wheel or the rim.

3 shows in principle the view of or in a sub-tool for the inventive production of a vehicle wheel, which looks a little different than that of 1 . 2 , In particular, this has with the tool after 3 producible wheel only five spokes. It consists of the sub-tool among others several, here four the shape of the annular section 11 the mold cavity shaped rim and in particular the wheel center M side facing away from determining segments U1, U2, U3, U4. In addition, there are five support cores S1-S5 which determine, among other things, one of the five spokes of the support ring S1-S5 which determines the wheel center M side of the circular rim, in the mold cavity, as it were, within these outer circle-ring-forming segments U1-U4 Rades in each of the five strut-like sections 12 be formed. Downtown 13 Finally, the mold cavity, the hub center part of the wheel surrounding the wheel center M is formed by injected when the tool is closed in the existing of said sections mold cavity provided with short fibers plastic material. But before, ie before closing the tool is band-shaped semifinished product 5 ( "Semi-finished band 5 ") As described below inserted into the mold cavity.

First, band-shaped semi-finished product 5 intended to reinforce the spokes of the wheel, as already based on the 1 . 2 was explained. For this purpose, each strut-like section is in each end region 12 the mold cavity is a pin-like approximately or substantially parallel to the running through the wheel center M perpendicular to the plane extending wheel axis of rotation aligned clamping element 14 respectively. 16 provided, each radially further inward clamping element 14 at the same time as a tool core for the formation of the 1 . 2 already mentioned holes 4 for the wheel bolts.

It is about the two clamping elements 14 . 16 a striving-like section 12 band-shaped semi-finished band 5 as shown several times led around or wrapped, so that starting from the first (parallel to the wheel axis of rotation aligned) clamping element 14 the with its surface substantially perpendicular to the plane aligned and, for example, 2 cm wide semi-finished band 5 or band-shaped semi-finished product 5 to the second radially outward clamping element 16 and around this back to the first clamping element 14 and this again rounding back to the second clamping element 16 to be led. Such wrapping of the two clamping elements 14 . 16 a striving-like section 2 can preferably be repeated several times, wherein the semi-finished band 5 tense and with his end finally suitable under tension is fixed.

Are all strive-like sections 12 wound or their clamping elements 14 . 16 wrapped as described, so is still band-shaped semi-finished 5 in the annular, the rim of the wheel forming section 11 of the mold cavity 1 brought in. In this case, on the segments U1-U4 facing outer sides of the support cores S1-S5, the semi-finished strip 5 laid out in such a way that the entirety of the support cores S1-S5 is wrapped several times and in multiple layers, in any case the first layer of the semifinished product strip 5 certainly at the distant from the wheel center M clamping elements 16 or at the already resting on this semifinished product tape 5 can come to the concern. Finally, the tool is closed and introduced into the mold cavity provided with short fibers plastic material, which then hardens. As it takes the place of the clamping elements 14 . 16 No plastic material can get there holes are formed in the finished component or wheel, which are either needed anyway or mean no functional limitation or may even represent a design element.

Of course, the plurality of segments U1-U4 for removing the fully formed in the tool wheel from the wheel center away as generally known displaced to remove the wheel despite the necessary undercuts, which need not be discussed here in more detail, from the tool can.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 4202287 A1 [0001]

Claims (7)

Method for producing a fiber composite structural part, which consists of an annular section ( 1 ) and a plurality of these radial sections supporting or supported on this ( 2 ) and by injection molding or injection molding of fiber reinforced plastic using prefabricated and in the mold cavity ( 11 . 12 . 13 ) of an injection molding tool inserted semifinished product ( 5 ), characterized in that the semifinished product, which is shaped in the form of a band and contains long fibers ( 5 ) not only to reinforce the annular portion ( 1 ), but also the individual radial sections ( 2 ) is in each case annularly inserted into the injection mold, after which the tool is closed and in the mold cavity ( 11 . 12 . 13 ) the substantially short fibers containing plastic material is injected, whereby the band-shaped semi-finished product is embedded therein. The method of claim 1, wherein the fiber composite structural part comprises a rim ( 1 ) as the annular section, of spokes ( 2 ) as radial sections and from a hub part ( 3 ) constructed wheel of a vehicle, in particular a motor vehicle, and wherein the band-shaped semi-finished product ( 5 ) contains substantially endless fibers, each extending uninterruptedly through the entire band between its two ends. Method according to claim 1 or 2, wherein the semi-finished strip ( 5 ) is at least slightly biased in the tool is inserted before the plastic material is injected. Method according to one of the preceding claims, wherein for the formation of the radial sections ( 2 ) or spokes ( 2 ) provided band-shaped semi-finished product ( 5 ) by two in the end region of each radial section ( 2 ) or each spoke ( 2 ) provided in the mold cavity of the tool pin-like clamping elements ( 14 . 16 ) to be led. Method according to one of the preceding claims, wherein in the case of a vehicle wheel as a fiber composite structural part for the formation of the hub part ( 3 ) a band-shaped semi-finished product is provided around pin-shaped clamping elements provided in the mold cavity. Method according to one of the preceding claims, wherein corresponding with the closing of the injection molding tool provided in the mold cavity of the sub-tool clamping elements provided in the upper tool clamping elements. The method of claim 6, wherein the clamping elements of the lower tool are at least slightly displaced into the lower tool by the impinging clamping elements of the upper tool.

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