1. TECHNICAL FIELD

The present disclosure relates to a fastening insert made of plastic with a T-shaped configuration, which is inserted into the material volume during the manufacturing of a component made of plastic or foam material or of a composite material and is fastened therein by curing of the material. Furthermore, the present disclosure relates to a component made of a plastic or foam material or a composite material in which such a fastening insert is arranged. In addition, the present disclosure comprises a connection of at least a first and a second component, wherein at least the first component comprises the abovementioned fastening insert. Furthermore, the present disclosure is directed towards a manufacturing method for the above-mentioned T-shaped fastening insert made of plastic as well as towards a manufacturing method for a corresponding component with this fastening insert.

2. BACKGROUND

In the prior art, components made of fiber-reinforced materials are equipped with fastening elements in order to be able to connect further components or attachment parts to them. According to a recognized procedure, the fastening elements are glued onto the component surface as it is described in U.S. Pat. No. 4,842,912. Such connections often have the disadvantage that the holding forces applying or acting only on one side of the fastening element cannot withstand the loads of the connection.

FR 3 013 253 further describes a fastening element consisting of a plate-like wire mesh. In the plate-like wire mesh, a blind rivet nut is arranged centrally in order to establish a connection with a threaded element. The plate-like wire mesh is cast into a component material during manufacturing of the component. Through the openings in the plate-like wire mesh, a through-flow of the wire mesh takes place, which ensures a respective fastening in the component. As this fastener is made of metal, unfavorable electrochemical potentials arise especially when used in combination with carbon fiber reinforced materials. These lead to electrochemical corrosion and a weakening of the connection.

GB 1 530 613 describes a fastening insert which also comprises a T-shaped configuration. The plate of the fastening insert has pins projecting on one or both sides which engage in adjacent woven fabric mats. The pins are arranged circularly around a central fastening opening and thus provide a rotation-proof arrangement of the fastening insert between the woven fabric mats. Since the plate defines a continuous face, no material-fit connection between material layers, which are adjacent and separated from each other by the plate, is possible in this face portion. This weakens not only the arrangement of the fastening insert but also the entire material composite of the component.

In addition, fastening inserts are known in the prior art, which have one or two perforated plates in their T-shaped configuration. The holes in the plates ensure a sufficient flow around the fastening insert, for example in a resin injection process (Resin Transfer Molding, RTM). At the same time, however, these fastening inserts can only be positioned inaccurately on and between woven fabric mats or material layers due to the lack of any position fixing. A further disadvantage is that a metallic fastening insert encourages electrochemical corrosion, especially in combination with carbon fiber reinforcements. Only the manufacturing of the fastening insert from stainless steel would prevent corrosion, which would, however, lead to additional material and manufacturing costs.

It is therefore the object of the present disclosure to provide a fastening insert which can be reliably anchored in the material of a component and thus provides a connection with a long lifespan. Furthermore, it is the object of the present disclosure to provide, by means of the fastening insert, a connection possibility with other connecting elements or attachment parts, which ensures a reliable and loadable or resilient connection and reduces the risk of electrochemical corrosion.

3. SUMMARY

The above object is solved by a fastening insert, by a component with this fastening insert, by a connection between a first and a second component, wherein the first component comprises the fastening insert, by a manufacturing method for the T-shaped fastening insert, by an alternative manufacturing method for the T-shaped fastening insert, as well as by a manufacturing method for a component comprising a T-shaped fastening insert. Further embodiments and developments are set forth in the following description, the accompanying drawings and the claims.

The fastening insert is made of plastic and has a T-shaped configuration. In addition, the fastening insert consists of an insert disc and a shaft which is fixedly arranged on the insert disc by means of a fastening section and projects beyond the insert disc on one side or on both sides with a functional section, of which at least the insert disc can be positioned in a foam material, a plastic material or a composite material during a component manufacturing and can be fastened therein by the component manufacturing, in which the insert disc comprises: two fastening sides arranged opposite one another, each of which at least partially forms an abutment face for adjacent layers of material, a plurality of passage openings arranged off-center around the shaft, which connect the fastening sides to one another and of which at least one passage opening comprises an edge projection extending circumferentially continuously or circumferentially in sections, which is formed as toothing and extends on one side or on both sides beyond the respective fastening side of the insert disc.

The fastening insert made of plastic is specially designed for components made of foam material, plastic or for components made of a composite material. In this context, a composite material consists of two or more composite or bonded materials. As a result, the composite material has different properties than its material components. Examples of composite materials are fiber-reinforced composites. These can have long or short reinforcing fibers. A further example is layered composite materials, which are also referred to as laminates. Fiber-composite materials manufactured in layers are also frequently referred to as laminates. In the present case, composite materials may be defined as fiber-plastic composites. These include carbon fiber reinforced plastics (CFRP), glass fiber reinforced plastics (GFRP), aramid fiber reinforced plastics (AFRP) and natural fiber reinforced plastics (NFRP). Components with advantageous mechanical properties consist of CFRP. The carbon fibers used in the plastic matrix can be of different lengths and configurations.

The fastening insert may be used in CFRP components. The CFRP components are manufactured from well-known fiber matrix semi-finished products. A fiber matrix semi-finished product is understood to be a semi-finished product made of a carbon reinforcing fiber impregnated with a plastic matrix. Known examples of such semi-finished products are pre-pregs. This semi-finished product consists of continuous fibers impregnated in a plastic matrix. The fibers either form a unidirectional layer or they are provided as woven fabric or laid structure. Other fiber matrix semi-finished products for CFRP components are SMC (Sheet Molding Compound) and BMC (Bulk Molding Compound). SMC are in most cases plate-shaped and are processed in a press mold. Thereby fastening inserts can be inserted into the press mold and can be processed. BMC is a formless mass which is processed as a molding compound or material using the well-known hot pressing technology. Furthermore, the BMCs can be processed with injection molding technology. At this, the reinforcing fibers are so short that they can flow through the mold during pressing or injection with the reaction resin. Furthermore, carbon fiber-containing organic sheets, which are processed by hybrid molding, are regarded as composite materials. In addition, woven fabrics, nonwoven fabrics as well as felts which are processed in a resin matrix are included. In addition, components are preferably manufactured from structural and/or integral foam with a reinforcing carbon fiber portion. Put simply, it is also preferred to construct a component structured from several plastic layers and to arrange the fastening insert between these layers.

The fastening insert, may achieve its T-shaped configuration by the combination of the insert disc and the shaft. Here, the insert disc is functionally mainly responsible for the fastening of the fastening insert in the foam material, the plastic or the composite material of the component. The shaft, in turn, with its fastening section forms a reliable mechanical coupling to the insert disc. In this way, the shaft is firmly connected to the insert disc. In addition, the shaft with its functional section provides a fastening option with the fastening insert and thus with the component in which the fastening insert is arranged.

The insert disc of the fastening insert according to the disclosure is distinguished by a disrupted structure. This disrupted structure may be formed by several passage openings. Since these passage openings each form a connection to the two fastening sides arranged opposite one another, an impregnating resin material or a fiber matrix semi-finished product, for example, can flow through these passage openings and harden inside them.

In order to be able to provide a mechanical position securing for the fastening insert both during the preparation of the manufacturing of a component and later in the component, at least one passage opening has a toothing projecting at least on one side. This toothing engages in the material of the later component which engages the respective fastening side of the insert disc, so that a positive or form-fit connection may be formed. The toothing projecting beyond the fastening side here is formed either completely or continuously circumferential or sectionally circumferential about the respective passage opening. Especially when the fastening insert is arranged on a woven fabric mat, a layer of reinforcing fibers, preferably carbon fibers, a plastic layer or a laminate, the toothing engaging the fibers and the adjacent material layer provides a positionally accurate retention of the fastening insert, for example in a mold for component manufacturing. At least one passage opening may have a projecting toothing on both opposite fastening sides, respectively. This is particularly advantageous if the fastening insert and in particular the insert disc are arranged between two material layers or woven fabric mats or fiber-reinforced laminates or similar material layers. This is because the toothings projecting on both sides ensure a secure retention and thus a positionally accurate arrangement of the fastening insert, for example in a mold for component manufacturing.

According to a further embodiment, the insert disc comprises at least one circumferential annular radial outer portion, in which a plurality of the passage openings is arranged uniformly or equally spaced from one another, wherein the passage openings are formed circularly and/or as a slot.

Due to its configuration, the insert disc may be divided into different functional portions. The openings arranged in an annular radial outer portion serve, among other things, to firmly arrange the fastening insert in the later foam material, plastic material or composite material. This is because these passage openings are intended to be flowed through by an impregnating resin, the plastic material or the composite material itself. In this way, it is ensured that the material layers arranged at opposite fastening sides of the insert disc are connected to each other. In addition, these passage openings in the radial outer portion serve to stitch the fastening insert preferably with a woven fabric mat, a nonwoven fabric, a felt or another material layer. Thus, on the one hand, the toothing helps in the realization of a positioning as does a stitching of the fastening insert.

According to a further embodiment, the shaft of the fastening insert is configured cylindrically or hollow-cylindrically. Furthermore, a first plurality of passage openings in the outer portion are arc-shaped slots, the toothings of which extend on both sides beyond the fastening sides of the insert disc.

The two-sided toothing of the several passage openings in the outer portion supports a reliable mechanical connection of the fastening insert, in particular the insert disc, to the adjacent material portions of the composite material, the plastic material and the foam material. In addition, due to the preferred toothing in the radial outer portion, it is ensured that the fastening insert counteracts a torque load with a high resistance to unscrewing. For, by means of the toothing arranged radially on the outer side of the insert disc, a relatively large lever arm for the fastening insert is created by the insert disc, with which lever arm the fastening insert retains itself against an external torque in the component material. In addition, the toothing may be arranged in the edge portion of slots extending in an arc-shaped manner. Thus, the toothing does not only extend over a portion formed at certain points. The flow-through areas of the slots also provide a retaining web rather than a retaining point, which mechanically complements the toothing for retaining the fastening insert.

According to a further embodiment of the fastening insert, the annular radial outer portion of the insert disc is arranged in a plane and surrounds a domed-shaped central portion which is domed out of this plane in the direction of the functional section of the shaft, wherein a concave recess of the central portion defines an at least annular radial free space which is arranged radially outwardly with respect to an outer shaft face.

The configuration of the insert disc defines an additional fastening portion by means of the dome-shaped central portion. For this portion is intended to receive a certain amount of adhesive which can be used to pre-fasten the fastening insert to a layer of material during the component manufacturing. For by means of this dome-shaped central portion, it is ensured that the adhesive is only arranged in the intended concave recess of the central portion. Regardless of the fastening insert being pressed against adjacent material layers, it is preferred that the adhesive does not emerge from this concave central portion, so that passage openings in the radial outer portion are not blocked by the adhesive, either. Thus, the domed configuration of the insert disc provides an additional arrangement option for the fastening insert without compromising the later mechanical integrity of the fastening insert.

According to a further embodiment, a second plurality of passage openings in the domed central portion of the fastening insert are arranged uniformly or equally spaced from one another and are formed circularly and/or as a slot. Furthermore, the first plurality of passage openings and the second plurality of passage openings may each have a toothing projecting on one side, which are aligned opposite to one another.

It may be preferred that several passage openings are arranged both in the domed central portion as well as in the radial outer portion. Irrespective of whether these passage openings are formed circularly or arc-shaped as slots, they comprise toothing opposing one another. Thus, the toothing of the passage openings may be arranged in the domed portion projects into the dome volume. In this way, this toothing ensures that the insert disc is anchored in the hardening or curing adhesive additionally with this toothing. The toothing projecting in the outer portion ensures an anchoring of the insert disc in a material layer which is positioned above the fastening insert. Here, it is understood that the shaft of the fastening insert projects or is threaded through a suitable opening in the overlapping or superimposed material layer.

According to a further embodiment of the fastening insert, the domed central portion surrounds an inner radial annular web, which ends axially with a radial outer edge of the domed central portion and defines an annular volume within the domed central portion. The portion defined in this manner serves to receive a volume of adhesive. This adhesive may be activated or cured by irradiation with light, given that the insert disc is provided of plastic which can be irradiated or is transparent. In addition, the defined annular volume ensures that the adhesive remains trapped or enclosed in this portion without, for example, blocking passage openings in the radial outer portion of the insert disc.

According to a further embodiment of the fastening insert, the shaft is provided as a bolt or a hollow cylinder which, at one side, extends beyond the insert disc. Furthermore, the shaft may be arranged in a central or non-central non-circular opening of the insert disc with a fastening end adapted to the shape, so that an anti-rotation protection is provided between the insert disc and the shaft. Furthermore, the shaft may have radially projecting anchoring features on a radial outer side in order to be able to additionally anchor or fasten the fastening insert via the shaft in a composite material or generally in a surrounding material.

The shaft and the insert disc may be connected to each other differently depending on the embodiment of the fastening insert. One possibility is that the shaft is latched, clamped, glued, welded or molded into a central non-circular opening of the insert disc. The non-circular opening provides an additional anti-rotation protection between the shaft and the insert disc. In this way, the above-described constructive features of the insert disc for anti-rotation protection complement the fastening of the shaft in the non-circular central or non-central opening.

It may be further preferred that at least the insert disc consists of a plastic which can be irradiated by light. This serves to activate or cure an adhesive that has been applied preferably in the domed portion of the insert disc. It may be furthermore preferred that the shaft is formed as closed at one end face adjacent to the insert disc and/or the insert disc of the fastening insert is formed as closed in a central portion adjacent to the shaft. This specific construction ensures that a metallic functional structure in the functional section of the shaft, for example, does not come into contact with reinforcing fibers of the composite material. Therefore, these constructive alternatives ensure that composite material cannot penetrate the inside of the shaft from the fastening side of the shaft during component manufacturing. This specific arrangement especially prevents electrochemical corrosion, which occurs, for example, when metal comes into contact with a reinforcing carbon fiber.

The present disclosure further comprises a fastening insert made of plastic with a T-shaped configuration consisting of an insert disc and a shaft, which is fixedly arranged on the insert disc by means of a fastening section and projects beyond said insert disc on one side or on both sides with a functional section, of which at least the insert disc can be positioned in a foam material or a composite material during a component manufacturing and can be fastened therein by the component manufacturing, in which the insert disc may comprise two fastening sides arranged opposite one another, which each form at least partially an abutment face and in which the shaft comprises a hollow cylindrical shape with a radial outer side as well as a radial inner side and is connected via the radial outer side to the insert disc and a metallic functional structure is non-positively or frictionally anchored to the radial inner side of the hollow cylindrical shaft or is positively or form-fittingly molded into the radial inner side of the hollow cylindrical shaft, so that a direct outward contact of the metallic functional structure with the composite material, the plastic material or the foam material is prevented at least adjacent to the insert disc by the shaft surrounding the functional structure and/or the insert disc.

The fastening insert may be characterized by providing a reliable retention in a manufactured component and a functionally effective arrangement of a metallic functional structure within the shaft of the fastening insert. Especially, the inner volume of the hollow cylindrical shape of the shaft provides sufficient space for such a metallic functional structure. Such metallic functional structures include wire thread inserts, metallic thread inserts, metallic connecting inserts and the like, which are molded into the plastic of the shaft or are non-positively or frictionally connected to it. In addition to these constructional properties, the fastening insert at the same time also ensures that the metallic functional structure cannot come into contact with the composite material, the plastic material or the foam material via the fastening end of the shaft. For this purpose, preferably either the insert disc is formed closed or the fastening end of the shaft comprises no opening in the direction of the insert disc. It is also possible that, although the shaft is formed open towards the insert disc, the composite material, the plastic material or the foam material cannot penetrate into the hollow cylindrical interior of the shaft during the component manufacturing. As a result, any reinforcing fibers, such as carbon fibers, which may be present in the foam material or composite material do not come into contact with the metallic functional structure. In this way, electrochemical corrosion is effectively prevented, which could endanger not only the functionality of the fastening insert but also its integrity.

As already mentioned above, according to a further embodiment of the fastening insert, the shaft is formed closed at an end face adjacent to the insert disc and/or the insert disc of the fastening insert is formed closed in a central portion adjacent to the shaft. According to a further embodiment of the fastening insert, the shaft comprises an inner thread on the radial inner side, in which a wire thread insert is arranged.

According to a further embodiment, the metallic functional structure consists of a wire thread insert. This wire thread insert reinforces an inner thread present on the hollow cylindrical inner side in the shaft made of plastic. This wire thread insert is only screwed so far into the depth of the shaft, i.e. in the direction of the insert disc into the shaft, so that it does not project out of the shaft at the fastening end thereof. In any case, this avoids the risk of possible electrochemical corrosion by contact with the foam material, the plastic material or the composite material. In combination with the wire thread insert, it also may be preferred to arrange the wire thread insert projecting axially beyond the functional section of the shaft. In this way, constructions of a wire thread insert can be combined with the shaft, which, for example, comprises a winding with a tapered diameter. If a screw is screwed into such a tapered winding, the latter can expand outwards and at the same time clamps the screwed-in screw in the wire thread insert. Such an arrangement would not be possible if the tapered winding of the wire thread insert would be formed within the hollow cylindrical shaft.

According to a further embodiment of the fastening insert, the inner thread comprises thread recesses located on the radial outer side, which comprise a continuous or sectionally circumferential free area or clearance in order to blunt the thread recess at least in certain portions.

The wire thread insert inserted in the inner thread of the hollow cylindrical shaft serves to reinforce and thus secure the continuance of the inner thread. At the same time, mechanical stresses are transferred to the material of the shaft via this wire thread insert, while, for example, a screw is screwed into the wire thread insert. In order to be able to transfer these mechanical stresses less material-intensively to the hollow cylinder shaft, radially outer thread recesses are selectively blunted. This results in the reduction of mechanical stress peaks that would otherwise occur at tapered radially outer thread recesses. In this way, a selectively arranged blunting of the otherwise tapered thread recess increases the lifespan of the inner thread of the hollow cylindrical shaft of the fastening insert.

According to a further embodiment of the fastening insert, the wire thread insert ends at a distance from an open or closed axial end of the shaft at the fastening section within the shaft. According to a further embodiment mentioned above, the wire thread insert extends beyond an axial exit of the shaft in the functional section and also comprises a winding tapered in diameter compared to other windings of the wire thread insert.

According to a further embodiment of the fastening insert, a metallic thread insert or a metallic connecting insert is glued to the radial inner side of the shaft and/or is non-positively or force-fittingly connected to the radial inner side of the shaft, preferably by clamping.

The use of metallic thread inserts or metallic connecting inserts in plastic parts is generally known. These are arranged, for example, in bores in plastic housings provided for this purpose. In addition to the adhesive connection between the plastic housing and the thread insert or connecting insert, especially the rigid construction of the plastic housing or plastic part provides the necessary mechanical support, stability and the mechanically loadable installation point for the thread insert or connecting insert. In comparison to these solutions, it became apparent that the combination of an insert disc and a shaft connected thereto constitutes an effective retaining construction. With this construction combined with embedding the fastening insert in a component material, the required stability of the shaft is provided to sufficiently retain a thread insert or connecting insert for a reliable connection. Since the shaft is anchored with reliable stability in a component, which is made of composite material for example, a reliable connection is achieved with a glued-in thread insert or connecting insert in the same way as with a wound wire thread insert molded into the shaft. For, according to a further embodiment of the fastening insert, a metallic thread insert or a metallic connecting insert or a wound wire thread insert is molded into the radial inner side of the shaft, so that these are at least positively retained in the shaft.

The molding of the thread insert or of the metallic connecting insert or of the wire thread insert can be carried out in different ways. One possibility is to heat the respective insert by means of a heat supply so that it transfers its amount of heat to the inner side of the shaft, softens it thereby and thus molds the insert into the inner side. According to a further embodiment, it is possible to equip the thread insert or connecting insert with a self-cutting or self-tapping outer thread. With this thread the insert is then screwed into the hollow cylindrical inside of the shaft. This allows the insert to cut itself a retaining thread in the inner side of the shaft.

Furthermore, it may be preferred to mold the wound wire thread insert into the inner side of the shaft already during the manufacturing process of the shaft. In general, it should be noted that a metallic thread insert dictates an inner thread, while its radial outer side serves to fasten the thread insert in the shaft. A metallic connecting insert provides any other fastening structure instead of an inner thread. This could be, for example, a latching connection or a bayonet connection. A wound wire thread insert that can be formed on the inner side of the shaft may be a block-wound wire thread insert. This ensures that no liquid plastic can penetrate into the inside of the wire thread insert, even during the manufacturing of the shaft with the wire thread insert arranged inside the shaft. In this context, it also may be preferred to close the wire thread insert by means of a plug. In this way it is ensured that the inner thread of the molded-in wire thread insert is not blocked by plastic residues even after the manufacturing of the fastening insert.

According to the disclosure, it also may be preferred that the thread insert or the connecting insert ends at a distance from an axial exit of the shaft at the fastening section inside the shaft. It also may be preferred that the thread insert includes a wire thread insert for thread reinforcement in its inside.

The present disclosure also includes a component consisting of a foam material, a plastic material or a composite material, in which a fastening insert according to one of the above-described embodiments is fixedly arranged within said material alternatives. Accordingly, the fastening insert in its various embodiments is embedded in a laminate component, in a layered component or in a composite component, wherein these components may have at least one textile layer or a fiber reinforcement layer. Thus, the component may consist of structural or integral foams with a carbon fiber reinforcement or of woven, nonwoven or felt layers reinforced with resin. According to another embodiment, the fastening insert is embedded in fiber matrix semi-finished products, such as BMC and SMC (see above), which may be carbon-fiber-containing molding compounds. According to a further embodiment, the fastening insert is embedded in carbon-fiber-containing organic sheets by means of hybrid molding.

Furthermore, the present disclosure comprises a connection of at least a first and a second component, of which at least the first component corresponds to the component described in the previous paragraph with an embedded fastening insert. Within the context of this connection, at least one first and the one second component are connected to one another by means of a fastening means and the fastening insert in the first component.

The present disclosure further includes a manufacturing method for a T-shaped fastening insert, in particular for a fastening insert according to one of the above-described embodiments. This manufacturing method comprises the following steps: providing an injection mold, the mold cavity of which dictates the structural features of the fastening insert in complementary form, filling the mold cavity with at least one flowing plastic, curing the plastic enclosed in the mold cavity and demolding the fastening insert from the injection mold.

In general, the fastening insert is manufactured according to its embodiments by means of an injection molding method. This injection molding method provides sufficient variety to realize the various geometric features, strength requirements, configuration designs with respect to the functional section of the shaft, as well as the necessary constructive features for fastening. It has been proved to be particularly advantageous to use a one-component injection molding method with only one plastic to fill the injection mold. In the same way, a two-component injection molding method, in which two different plastics are used in the manufacturing process, is also advantageous, especially for higher mechanical demands on the fastening insert to be manufactured. For this two-component injection molding method makes it possible, for example, to use two plastics with different chemical compositions or two plastics with a different proportion of reinforcing fibers for the manufacturing of the shaft and the insert disc. Of course, other combinations of material configurations are also possible here (see below).

According to a further embodiment of the manufacturing method, the mold cavity is filled with only one plastic, so that the fastening insert is manufactured using a one-component injection molding method, or the mold cavity is filled with a first plastic in the portion of the insert disc to be molded and with a second plastic in the portion of the shaft, so that the fastening insert is manufactured using a two-component injection molding method.

The preferred one-component injection molding method provides a fastening insert that is identical in material with respect to the insert disc and the shaft of the fastening insert. Already with regard to the choice of material and the steps to be carried out, this method is associated with less effort compared to, for example, a two-component injection molding method. The two-component injection molding method may open up the possibility of processing accordingly selected plastics with the two-component injection molding method with regard to the constructive requirements and the functional requirements of the shaft and the insert disc. Since it is preferably the insert disc that transfers high retention forces of the fastening insert into the component material, a plastic of high mechanical stability is recommended here. Therefore, a plastic with a high proportion of reinforcing fibers may be injected into the injection mold for the insert disc. With regard to the plastic used to form the shaft, it may be preferred to use a plastic that is easy to shape after curing. Because this plastic opens up the possibility of combining the shaft of the fastening insert with various thread inserts and connecting inserts or of molding these into the radial inner wall of the shaft.

According to a further embodiment, which is specifically based on the two-component injection molding method, the first and second plastics are identical and differ in a proportion of reinforcing fibers. Alternatively, the first and second plastics are different in a chemical composition or the first and second plastics are different in a chemical composition and comprise different proportions or amounts of reinforcing fibers. With this preferred material design, which refers to the characteristics of the components of the fastening insert to be met, the constructive features of the fastening insert as described above are optimally supported by the choice of material.

According to a further embodiment, at least the insert disc is transparent or at least light-permeable or can be irradiated by light after manufacturing using the first plastic.

It has often proved to be difficult to arrange the fastening insert positionally accurate in the component form during the component manufacturing and to fix or retain it there. This is because even the arrangement of a further layer of material on top of the fastening insert can cause it to change its previously adjusted position. In this context, it has proved advantageous to pre-fix the fastening insert using a light-activated or curable adhesive during the component manufacturing. For this purpose, such an adhesive may be applied to the bottom side of the insert disc, preferably in the domed portion of the insert disc, and the insert disc is subsequently arranged on the existing layer of material, plastic or woven fabric. This adhesive is activated and/or even cured with the help of the specific irradiation of light, so that the fastening insert is pre-fixed. This adhesive connection does not replace the later retention of the fastening insert to be realized by the component material in the component compound. Rather, it creates a temporary fixation so that the further designs of the material layers which overlay the fastening insert cannot endanger its positioning.

According to a further embodiment, the injection mold defines an insert disc having two opposite fastening sides with a plurality of passage openings arranged off-center about the shaft, which connect said fastening sides to one another and of which at least one passage opening has an edge projection extending circumferentially continuously or circumferentially in sections, which is formed as toothing and extends beyond the respective fastening side of the insert disc on one or both sides. With regard to the designs of the insert as described above for the reliable arrangement of the fastening insert in the component, it may be preferred that the injection mold dictates precisely the constructive features of the insert disc by its complementary form design. Accordingly, the advantages of the correspondingly shaped insert disc as described above result from this complementary form design.

Alternatively or in addition to the design of the injection mold for the special forming of the insert disc, it is further preferred according to the invention that the injection mold contains a core which defines a radial inner wall of a shaft of the fastening insert, so that a thread is formed on the radial inner wall. This design of the injection mold refers to the construction of the shaft. This is because during the injection molding process, the shaft is adapted to reliably receive a wire thread insert or differently shaped thread inserts in its inside.

According to a further embodiment for the design of the shaft, a wire thread insert is installed in the thread of the radial inner wall of the shaft after the demolding of the fastening insert. Such an installation uses a known installation tool for wire thread inserts. The installation tool will grip the wire thread insert at its installation tang or a similar installation end and screw it into the inner thread of the shaft.

It further may be preferred that the manufacturing method comprises the further step: positioning a wire thread insert or a thread insert or a connecting insert in the mold cavity and molding in the wire thread insert, the thread insert or the connecting insert when filling the mold cavity with liquid plastic. According to this preferred method alternative for the manufacturing of the fastening insert, the functional section of the shaft is already further designed during the manufacturing method. This prevents the need for an additional special installation step for a metallic functional structure to follow the manufacturing of the fastening insert. This is because, according to the designs of the manufacturing method, it is possible in an effective manner to place known thread inserts or connecting inserts or block-wound wire thread inserts within the injection mold in such a manner that, once the manufactured fastening insert has been molded, they appropriately configure the function of the inner wall of the shaft.

According to a further embodiment of the manufacturing method of the fastening insert, this comprises the further step of: installing a thread insert or a connecting insert by means of a thermal or mechanical method in the shaft of the fastening insert after the fastening insert has been demolded. In accordance with this preferred embodiment of the manufacturing method, initially the fastening insert is manufactured by injection molding. After it has been demolded from the injection mold, an installation step for the thread insert, the connecting insert or another metallic functional element follows. In this context, for example, the plastic of the shaft is thermally softened in order to be able to form a thread insert or a connecting insert inside the shaft. This heating may be possible by friction welding, ultrasonic welding or by irradiation with a heat source. Alternatively, it also may be preferred to provide the thread insert or the connecting insert with a self-cutting or self-tapping outer thread so that it can be screwed into the shaft of the fastening insert. Based on this approach, the thread insert or connecting insert is retained within the shaft non-positively or frictionally and positively or in a form-fit manner. It also may be preferred that the metallic functional structure is constructed flexibly or springy so that it can be inserted into the shaft in a compressed state. After this insertion is completed, the functional structure is unloaded so that it expands within the inside of the shaft. As a result of this expansion, the metallic functional structure becomes stuck and/or is at least non-positively or frictionally anchored in the hollow cylindrical interior of the shaft.

The present disclosure includes a further manufacturing method for a T-shaped fastening insert, in particular for one of the above-described embodiments of the fastening insert. This manufacturing method comprises the following steps: providing an insert disc of the fastening insert made of plastic, may be of transparent plastic or plastic which can be irradiated by light, which has two fastening sides arranged opposite one another with a plurality of passage openings arranged off-center about the shaft, which passage openings connect the fastening sides to one another and of which at least one passage opening comprises an edge projection extending circumferentially continuously or circumferentially in sections, which is formed as toothing and extends on one or both sides beyond the respective fastening side of the insert disc, providing a shaft of the fastening insert and connecting the insert disc and the shaft captively to form a T-shaped fastening insert.

This alternative manufacturing method for the T-shaped fastening insert is based upon the premise that initially the insert disc and the shaft of the fastening insert are manufactured separately. In a subsequent step, the two basic components of the fastening insert are connected to one another. This approach opens up the possibility of initially being able to optimally adapt the individual components of the fastening insert to the respective requirements in the later installation state in the component. Accordingly, a mechanically stable plastic with fiber reinforcement is used to manufacture the insert disc. Since the shaft does not have to consist of the same plastic, it is not necessary after this manufacturing route to adapt a complex two-component injection molding method to the manufacturing of the fastening insert. This is because the shaft is made of a different plastic parallel to the insert disc, which meets the functional requirements. Subsequently, the insert disc and the shaft are connected to one another in such a manner that they constitute a reliable structural unit.

In the form of the manufacturing method described above, the insert disc and the shaft are connected by: mechanically clamping or latching the shaft in a central or decentral opening of the insert disc, or thermally connecting the shaft and the insert disc, preferably by ultrasonic welding or friction welding, or adhering the shaft and the insert disc. These various connection possibilities for the shaft and the insert disc ensure a reliable connection between the insert disc and the shaft. At the same time, they also make it possible to freely choose the plastics or, more generally, the materials used to manufacture the insert disc and the shaft, especially when the shaft is mechanically clamped and latched in a central or decentral opening of the insert disc. In this way, the fastening insert can be adapted to any component configuration. According to a further embodiment of the present manufacturing method, the insert disc comprises two oppositely arranged fastening sides with several passage openings arranged off-center about the shaft, which connect the fastening sides with one another and of which at least one passage opening has an edge projection extending circumferentially continuously or circumferentially in sections, which is formed as toothing and extends on one side or on both sides beyond the respective fastening side of the insert disc.

According to a further embodiment of the manufacturing method described above, a radial inner wall of the shaft of the fastening insert is provided with a thread and a wire thread insert is installed in the thread of the radial inner wall of the shaft. It has already been described above that a thread located on the inner radial wall of the shaft can be reinforced by means of a wire thread insert. This design of the shaft is possible in the same way after the manufacturing of the fastening insert in the injection molding method as with a separate manufacturing of the insert disc and the shaft and the subsequent assembly of these two structural components. Thus, the shaft may be manufactured with an inner thread and the wire thread insert is subsequently installed in this inner thread to reinforce it. Subsequently, the insert disc and the shaft are connected according to the manufacturing routes described above.

As an alternative to the installation of the wire thread insert, it also may be preferred in the present manufacturing method to install a thread insert or a connecting insert by means of a thermal or mechanical method or an adhesive method in the shaft before or after the insert disc has been connected to the shaft.

The present disclosure further includes a method of equipping a T-shaped fastening insert, preferably a T-shaped fastening insert according to the preferred constructive designs described above. This equipment method comprises the following steps: providing a single T-shaped fastening insert or a component with a T-shaped fastening insert attached thereto and installing a wire thread insert in a thread on a radial inner wall of a shaft of the T-shaped fastening insert or installing a thread insert or a connecting insert by means of a thermal or mechanical method or an adhesive method in a shaft of the T-shaped fastening insert.

By this equipment method it is underlined that the fastening insert can already be equipped with its metallic functional structure during its manufacturing or in a subsequent equipment method. Accordingly, it may be preferred to equip the single fastening insert or a fastening insert already embedded in a component with a wire thread insert, a thread insert or a connecting insert. These steps are performed in the same way as they have already been described above. The equipment method offers the flexibility of being able to equip the shaft at the manufacturer of the fastening insert or at the component manufacturer or even at the component customer.

The present disclosure further includes a manufacturing method for a component made of a composite material, of plastic or of another foam material, with a T-shaped fastening insert comprising an insert disc and a shaft fastened thereto, preferably a fastening insert according to the above-described embodiments. The manufacturing method for the component comprises the following steps: providing a component mold with at least one first material layer, may be a fiber layer or plastic layer or a woven fabric layer, wherein the component mold defines a complementary shape of a component to be manufactured, positioning and pre-fixing the fastening insert on the at least one first material layer, wherein the pre-fixing is achieved by establishing a material-bonded and/or positive or form-fit connection between a first fastening side of the insert disc facing the first material layer and the first material layer, after step II embedding the connection of the fastening insert and the first material layer in a plastic, a fiber-reinforced plastic, a resin or in a foam material with or without fiber reinforcement.

The fastening insert may be embedded in components of various types of material. The constructive features of the insert disc are particularly helpful in ensuring a reliable positioning of the fastening insert during the manufacturing. The toothing and the further designs of the insert disc are suitable for retaining or fixing the fastening insert on a first material layer. This first material layer consists of a fiber layer of carbon fibers or glass fibers, a woven layer of such fibers, a nonwoven, a felt or a pre-processed molding compound with reinforcing fibers, according to various embodiments. Furthermore, it may be preferred to arrange the fastening insert on a first layer of a plastic or a structural or integral foam with a fiber reinforcement, such as a carbon fiber reinforcement. Because even on this structured material layer, the constructive design of the insert disc supports a reliable positioning of the fastening insert. After the fastening insert has been arranged at the desired position, the remaining cavity of the component mold is filled with the desired component material and the component is subsequently demolded.

According to a further embodiment of the manufacturing method, the latter comprises the further step: arranging at least a second material layer, a second fiber layer or plastic layer or a woven fabric layer, on a second fastening side of the insert disc facing the second material layer in such a manner that the second material layer surrounds the shaft of the fastening insert.

The component may comprise at least two material layers, which, according to an embodiment, are composed of reinforced fibers. Such fibers are, for example, carbon fibers or glass fibers, wherein other reinforcing materials can also be inserted into the component form. Since the insert disc of the fastening insert also has a projecting toothing on the second fastening side in accordance with the embodiments described above, this toothing also provides an additional grip or hold in the second fiber layer or material layer. Thus, the fastening insert is at least mechanically pre-fixed between two adjacent fiber layers or material layers so that it is arranged positionally accurate during the manufacturing method of the component.

According to a further embodiment of the manufacturing method, an impregnation of the stack of the first and the second material layer with the intermediate fastening insert with a liquid resin material as well as a curing of the material to a component of a multi-layer composite material is performed.

Further, the manufacturing method is distinguished by the pre-fixing being achieved by a positive or form-fit connection by means of a toothing on the first fastening side of the insert disc, which engages at least in the first material layer and hooks into it. According to an alternative or additional embodiment of the present manufacturing method, the pre-fixing is performed by a material-bonded connection by means of a connecting adhesive between the first fastening side of the insert disc and the first material layer, which is cured by means of light and/or heat.

As already described above, the toothing of the insert disc ensures a safe positioning and fixing of this position on and between the material layers of the component to be manufactured. For this, the toothing engages in the respective adjacent material layer. This applies both to a material layer arranged on only one fastening side and to two material layers arranged on the two opposite fastening sides of the insert disc. In order to support this form-fit fixing or positioning aid, it also may be preferred to pre-fix the fastening insert by means of an adhesive. In this context, the use of light-curing adhesives has proved to be particularly helpful.

According to a further embodiment, an adhesive is applied in a concave recess of the first fastening side of the fastening insert and the adhesive is cured by light irradiation after the positioning on the first material layer by irradiating the insert disc consisting of a transparent material or a material which can be irradiated by light. Since the pre-fixing adhesive spot may be limited to the portion of the concave recess, the adhesive spot optimally complements the mechanical pre-fixing of the insert disc. In addition, the adhesive spot does not negatively influence the embedding of the fastening insert in the component material. This is because the adhesive spot preferably does not block the openings in the radial outer portion of the insert disc, so that these can be flowed through by an impregnating resin material, for example.

According to a further embodiment of the present manufacturing method, in a further step, a fixing of the second fastening side of the insert disc takes place at least by means of a positive or form-fit connection at the second material layer by that a toothing at the second fastening side of the insert disc engages at least in the second material layer. In addition, as an alternative to or in addition to the mechanical pre-fixing described above, it is preferred to stitch the fastening insert onto at least the first material layer.

According to a further embodiment of the present manufacturing method, the component is manufactured in an RTM (Resin Transfer Molding) process or by cold pressing or hot pressing.

