FIBRE COIL AND WINDING DEVICE FOR WINDING A FIBRE COIL
20230183122 · 2023-06-15
Inventors
Cpc classification
B65H2701/32
PERFORMING OPERATIONS; TRANSPORTING
B65H71/00
PERFORMING OPERATIONS; TRANSPORTING
International classification
Abstract
The invention relates to a winding device (100) for winding a fibre coil, comprising a coil carrier (110) for wrapping with fibre (210) in order to produce a coil body (220) made of wound fibres (210), a fibre supply (120) for supplying a fibre (210) for wrapping the coil carrier (110), and an adhesive device (130) for producing droplets of adhesive (140) for bonding the outermost layer of fibres (210) on the coil body (220) to fibres (210) freshly laid onto the coil body (220).
Claims
1-15. (canceled)
16. A winding device for winding a fiber coil, comprising a coil carrier for wrapping with fiber in order to produce a coil body made of wound fiber; a fiber feeder for feeding a fiber for wrapping the coil carrier; and an adhesive device which is suitable for producing droplets of adhesive and for conveying the droplets of adhesive specifically onto the outermost layer of fiber on the coil body to produce individual adhesive dots thereon and to bond the outermost layer of fiber on the coil body to fiber newly placed onto the coil body.
17. The winding device according to claim 16, wherein the adhesive device is suitable for producing the droplets of adhesive having a predetermined size, preferably by means of a volumetric dosing method.
18. The winding device according to claim 16, wherein a distance (d) of a discharge point of the droplets of adhesive from the adhesive device to the outermost layer of fiber is less than 10 cm, preferably less than 5 cm.
19. The winding device according to claim 16, further comprising a positioning device suitable for moving the coil carrier and/or the adhesive device in such a manner that the droplets of adhesive hit a predetermined position on the outermost layer of fiber on the coil carrier.
20. The winding device according to claim 16, further comprising a radiation source emitting in the wavelength range of UV and/or visible light for irradiating the adhesive applied to and/or between the fiber, wherein the droplets of adhesive consist of adhesive which cures under irradiation with UV and/or visible light.
21. The winding device according to claim 20, wherein photoinitiators in the adhesive are matched to the spectral composition and intensity of the UV and/or visible light after penetration of the fibers.
22. The winding device according to claim 20, wherein the adhesive device is suitable for applying droplets of adhesive to the outermost layer of fiber while the winding of new fiber onto the coil body is being interrupted; the coil carrier and the fiber feeder are suitable for winding new fiber onto the coil body after application of the droplets of adhesive in order to bond it to the outermost layer of fiber; and the radiation source is suitable for irradiating the droplets of adhesive thereon with light to cure the droplets of adhesive.
23. The winding device according to claim 20, wherein the adhesive device is suitable for applying droplets of adhesive to the outermost layer of fiber while new fiber is being wound onto the coil body; the coil carrier and the fiber feeder are suitable for winding new fiber onto the coil body while applying the droplets of adhesive in order to bond it to the outermost layer of fiber to which droplets of adhesive have already been applied; and the radiation source is suitable for irradiating these droplets of adhesive with light during the winding of new fiber onto the coil body to cure them; or the radiation source is suitable for irradiating the droplets of adhesive with light, after winding has been interrupted.
24. The winding device according to claim 22, wherein the irradiation with light takes place only after multiple fiber layers bonded with droplets of adhesive have been wound or when the fiber coil has been wound completely.
25. The winding device according to claim 16, wherein the adhesive device is suitable for applying the droplets of adhesive to the respective outermost layer of fiber in such a manner that air spaces are present between the droplets of adhesive and the fiber of the fiber coil, which are connected to one another by air ducts.
26. The winding device according to claim 16, wherein the adhesive device is suitable for applying the droplets of adhesive to the respective outermost layer of fiber in such a manner that the completely wound fiber coil has no air spaces between the fiber and the adhesive.
27. A fiber coil made of wound fiber, wherein superimposed layers of the fiber are exclusively bonded together with cured individual droplets of adhesive.
28. The fiber coil according to claim 27, wherein air spaces are present between the droplets of adhesive and the fiber of the fiber coil, which are interconnected by air ducts.
29. The fiber coil according to claim 27, wherein the fiber coil has been produced with a winding device.
30. The fiber coil according to claim 29, wherein the winding device comprises: a coil carrier for wrapping with fiber in order to produce a coil body made of wound fiber; a fiber feeder for feeding a fiber for wrapping the coil carrier; and an adhesive device which is suitable for producing droplets of adhesive and for conveying the droplets of adhesive specifically onto the outermost layer of fiber on the coil body to produce individual adhesive dots thereon and to bond the outermost layer of fiber on the coil body to fiber newly placed onto the coil body.
Description
[0042]
[0043]
[0044]
[0045]
[0046]
[0047]
[0048]
[0049]
[0050] As shown in
[0051] The winding of the fibers 210 onto the coil carrier 110 can be carried out according to any method known from the prior art. In the simplest case, one end of the fiber 210 is secured to the coil carrier 110 and wound onto it by rotating the coil carrier (as symbolized by the arrow), while the fiber feeder 120 ensures that the newly wound fibers 210 cover the entire width of the coil body 220 by movements perpendicular to the image plane.
[0052] If both ends of the finished coil 200 must be accessible from the outside, the fiber 210 is secured, for example, bonded, to a central section on the coil carrier 110 or a holder that can be secured to, e.g., fit onto, the coil carrier 110. The two ends of the coil are then alternately wound over the coil carrier 110, e.g., by rotating the coil carrier 110 with intermediate fixation of the fiber or by moving the fiber feeder 120 around the coil carrier 110. Since such winding methods are known to a person skilled in the art from the prior art, further explanations in this regard are omitted here.
[0053] The winding device 100 further comprises an adhesive device 130 which dispenses droplets of adhesive 140 from a discharge point 132. The droplets of adhesive 140 get onto the coil body 220 and/or the fed fiber 210 and bond the newly fed fiber 210 to fiber 210 already wound onto the coil body 220. Thus, the outermost layer of fiber 210 of the coil body 220 is bonded to the newly placed fiber 210.
[0054] As shown in
[0055] The use of droplets of adhesive 140 for bonding offers the advantage that the “open-pore” fiber coils described with reference to
[0056] For this purpose, as shown in
[0057] Preferably, the size of the droplets of adhesive 140 can be volumetrically dosed in this case, i.e., the volume of the droplets of adhesive 140 is fixed at a certain value or can be set at a certain value.
[0058] An example of this is droplet generators or jet valves, which make use of jet valve technology, which is in itself known from the prior art. Nevertheless, a brief explanation of this technology should be given with reference to
[0059] As shown in
[0060] The adhesive 145 is forced into and out of the duct by a pneumatically or piezo-driven actuator by means of a high momentum cylinder 136, cf.
[0061] Thus, by means of jet valve technology, volumetrically dosed droplets can be produced which exit the adhesive device 130 at a sufficiently high speed to exhibit a linear path in good approximation even against gravity for a distance of several centimeters. This allows the droplets of adhesive 140 to be shot onto the coil body 220 in a precisely positioned manner, thereby placing them on its surface. Due to the compact design size of such jet valves, they can also be integrated almost arbitrarily into existing winding machines.
[0062] The distance d from the discharge point 132 to the surface of the coil body 220 is preferably less than 5 cm, at most less than 10 cm, e.g., between 1 cm and 5 cm. Indeed, it has been found that, in addition to the desired main droplet on the coil body 220, smaller satellite droplets are formed around the main droplet for a greater distance. These satellite droplets can result in unwanted bonding points or, if cured prematurely, imperfections in the winding pattern. To avoid this, the distance d is preferably limited to less than 5 cm. The distance d can also be kept constant in this case if the adhesive device 130 can be moved away from the coil body 220 as the number of fiber layers in the coil body 220 increases, e.g., by means of a linear motor or the like.
[0063] Droplet ejection from the adhesive device 130 can be performed by means of a piezoelectric or pneumatic actuator. In this way, a large number of droplets per second can be ejected, e.g., up to 250, 300 or 350 droplets per second for pneumatic actuators and up to 2000 droplets per second for piezoelectric actuators. In this way, sufficiently large quantities of droplets of adhesive 140 can be produced to wet the coil body 220 fully automatically with adhesive 145 for application of the next fiber layer.
[0064] Examples of such jet valves represent micro-dispensing valves, hose pinch valves or diaphragm dispensing valves from the manufacturers DELO, Nordson, Techcon or BioFluidx.
[0065] In this process, as shown schematically in
[0066] For example, the adhesive device 130 can be moved by a linear motor not only away from the coil body 220 (Y-direction in
[0067] Furthermore, the adhesive device 130 can be dynamically adjustable in its angle to the coil surface so that droplets of adhesive 140 can be applied across the entire width of the coil body without movement across the width of the coil body (X-direction in
[0068] Furthermore, the coil carrier 110 and thus the coil body 220 can be rotated, as symbolized by the arrow A in
[0069] In this way, a large number of droplets of adhesive 140 can be applied in a fully automated manner to arbitrarily selectable spots on the surface of the coil body 220 in order to achieve an optimal bonding result and thus an optimal winding result.
[0070] The adhesive 145 from which the droplets of adhesive 140 are formed can, in this case, have a consistency that allows mutual fixation of sections of the fiber 210 without the adhesive 145 being completely cured. In this case, the completely wound coil body 220 can be removed from the winding device 100 in a conventional manner (e.g., while still on the coil carrier 110) and stored, placed in an oven, and/or irradiated with light to cure the adhesive 145. In addition, the coil body 220 can be additionally potted with a potting compound to provide more stability to the finished fiber coil 200.
[0071] As shown in
[0072] In principle, the adhesive 145 can be any adhesive known from the prior art that cures under radiation. The light used can have a wavelength of 100 nm to 780 nm, preferably from 300 nm to 550 nm, more preferably from 315 nm to 420 nm. For example, acrylates that cure exclusively under radiation can be used, such as DYMAX 431. Due to radical polymerization, these cure very quickly, e.g., in a period of a few seconds, approximately between 1 s and 10 s. Curing takes place only during irradiation and is therefore easily controllable.
[0073] Curing is fast and complete, and post-curing is not required. This makes it possible to bond sections of fiber 210 firmly together in a fast and reliable manner.
[0074] In contrast to 2-component reactive adhesives, radiation-curing reactive adhesives do not have a so-called pot life or open time, after which the viscosity of the adhesive increasingly increases and curing takes place. This means that with radiation-curing adhesives, regular cleaning of all components of the adhesive device 130 that come into contact with adhesive, such as the reservoir, ducts and the valve, can be omitted. It is sufficient to refill the adhesive regularly. Furthermore, the adhesive viscosity remains constant, which contributes to process stability.
[0075] So-called 1C epoxy resin adhesives can also be used. Cationic polymerization occurs in these within seconds following light activation. An example of this is DELO KATIOBOND. In adhesives 145 of this type, curing takes place even after the end of irradiation in shadow areas. As a result, curing is continuous and thus more homogeneous.
[0076] Alternatively, adhesives 145 for which thermal post-curing is possible can also be used. Examples of corresponding acrylates are Noa 83H or DELO DUALBOND. Such adhesives make it possible to preliminarily fix the fiber 210 by means of the radiation source 160 and to produce the subsequent final strength in an oven. Again, irradiation for a few seconds, e.g., only one or a few seconds, is sufficient for pre-curing.
[0077] A wide range of adhesives can therefore be used. The decisive factor in this case is that the adhesives can be applied in an automated manner in droplet form to the incoming fiber 210 or the coil body 220.
[0078] The bonding and fixing of the superimposed fiber 210 is shown schematically in
[0079] In this case, the droplets of adhesive 140 can form a closed chain, i.e., they can be in communication with one another. However, they can also be separated from one another, i.e., they can lie individually. In principle, any arrangement of droplets of adhesive 140 is possible, as long as the entire fiber composite in the finished fiber coil 200 is fixed against one another in such a manner that the original winding of the fiber 210 is maintained, i.e., that a compact, homogeneously wound fiber coil 200 is formed. For this purpose, it is sufficient, for example, if a section of the fiber 210 is firmly connected to a single adjacent section of the fiber 210 in such a manner that no mutual displacement is possible as long as all sections of the fiber 210 form a network of fiber sections firmly connected in this way via droplets of adhesive 140. In addition, it can also be possible not to fix individual sections of the fiber 210 with adhesive as long as they are fixed in the coil body 220 due to the tight connection of the sections of the fiber 210 surrounding them.
[0080] After the droplets of adhesive 140 have been applied to the outermost layer of fiber, fiber 210 is wound onto the coil body 220 in accordance with the winding process carried out with the winding device 100 to form the next layer of fiber (shown hatched in
[0081] As shown in
[0082] In this process, irradiation with light 165 may occur after application of each new layer of fiber 210, as shown in
[0083] On the other hand, curing the adhesive 145 fiber layer by fiber layer offers the advantage that newly wound fiber 210 is always placed onto a firmly bonded overall body and not onto a loosely bonded and thus deformable layering of fiber 210 and adhesive 145. This makes it possible to pull the newly placed fiber 210 more tightly over the coil body 220 than would be possible for adhesive bonds that have not been previously cured, since it is not possible to cut the newly placed fiber 210 into the still deformable coil body 220. This allows for a more compact arrangement of the fibers 210. In this connection, it should also be noted that, even with a relatively loose winding due to low tensile force after application of multiple fiber windings, the innermost fiber layers are subjected to greater pressure than the outer fiber layers due to the fiber layers wound on them. To avoid this effect, the tension on the fed fiber 210 would have to be reduced with increasing winding thickness, which is costly in terms of process technology. However, the effect can also be avoided or reduced in a simple manner by curing the bonding between 2 to 5 fiber layers if such curing is done before new fiber 210 is applied.
[0084] As indicated in
[0085] Alternatively, after the adhesive 145 has been completely covered with newly placed fiber 210, i.e., after a fiber layer has been completely wound, the entire coil body 220 can be irradiated with light 165. For this purpose, multiple radiation sources 160 can be used, or the winding process can be carried out in a housing which reflects the radiation, whereby complete exposure to light 165 can also be achieved with only a single radiation source 160.
[0086] Compared to a full-area irradiation with light 165, however, it can also be advantageous if the light 165 is irradiated in a focused manner only on a specific spot of the coil body 220, i.e., if curing of the adhesive 145 can be performed selectively and locally. This is shown, for example, in
[0087] By combining the adhesive droplet positioning, the winding process and the irradiation, different process variants for winding and bonding fiber coils 200 can be realized.
[0088] For example,
[0089] After these adhesive dots have been applied, the winding process is resumed and another layer of fiber 210 is wound onto the coil body 220. The droplets of adhesive 140 are thus covered by this new layer of fiber. This is shown in
[0090] In this connection, prior to application of the next droplets of adhesive 140, the droplets previously covered with fiber -with the winding process again interrupted- can be cured by means of irradiation by the UV source 160, resulting in the three-step process of application of the adhesive, unwinding of the coil, curing of the adhesive, which is carried out continuously until the fiber coil is completed.
[0091] Whereas in
[0092] In the example of
[0093] New fiber 210 is continuously applied over these droplets of adhesive 140, as the winding device 100 is running. In
[0094] The curing of the adhesive 145 can, in this case, be performed with the winding process interrupted, similar to the variant of
[0095] Alternatively, curing can also take place via local irradiation without interrupting the winding process. In this process, the light 165 is focused on droplets of adhesive 140 that are already covered with fiber 210. In addition, shielding is preferably provided with respect to uncovered droplets of adhesive 140. For example, light 165 can be emitted from an optical fiber terminating close to the coil body 220 in a nearly point-like manner onto the coil body 220. This variant achieves the highest production rate due to the lack of need to interrupt the winding process, but is complex in terms of process technology, since sufficient shielding of the light 165 and coordination of adhesive application, winding and curing must be ensured.
[0096] In all of the above variants, exposure to light 165 can also occur only after multiple fiber layers have been applied, as described above. Furthermore, in all variants, it is possible to provide multiple rows of adhesive dots per newly wound fiber layer to improve the stability of the winding. In addition, the radiation source 160 can also be used to specifically cure droplets of adhesive 140 on which no fiber 210 has yet been deposited. This can be done to specifically introduce spacers or special structures into the coil.
[0097] A number of other process designs are also possible. The decisive factor for the fully automatic and thus fast and cost-effective production of fiber coils 200 wound as compactly and homogeneously as possible is the sequence of applying adhesive 145 and winding fiber 210, supplemented if necessary by curing the adhesive 145 by appropriate irradiation. If this intermediate curing by irradiation is omitted, the curing can either take place after complete winding or the fiber coil 200 is thermally cured, e.g., in an oven.
[0098] Due to the use of individual droplets of adhesive 140 instead of applying adhesive 145 over the entire surface, fiber coils 200 with an open-pore structure can be produced. As shown in
[0099] As shown in
[0100] However, the open-pore structure also means that fabrication can be accelerated, as less adhesive 145 needs to be applied to the coil body 220. Subsequently, the thus produced fiber coils 200 can be additionally potted. This can be done, e.g., by placing the coils in a bath of potting compound and then applying a vacuum. As a result, air is drawn out of the interspaces between the fibers 210 and potting compound flows in instead. The “fiber coil sponge” thus fully saturated with potting compound can then be cured in an oven. Alternatively, the open-pore fiber coil can be potted in a conventional manner in a potting mold.
[0101] If an open-pore structure is not desired, appropriate dosage and positioning can also be used to produce a fiber coil 200 that has a closed-pore structure, i.e., that individual air spaces 230 are not interconnected by ducts, or a fiber coil 200 in which all interspaces between fibers 210 are filled by adhesive 145. Such fiber coils 200 are heavier but have greater stability.
[0102] In all of the cases described above, the coil carrier 110 can be removed from the coil body 220 or from the finished fiber coil 200 after the adhesive 145 has cured. This allows pressure to be removed from the fiber 210, particularly, the inner fiber layers, thereby improving the coil properties.
[0103] The use of an adhesive device 130, which provides droplets of adhesive 140 for bonding fiber 210 that has already been wound with fiber 210 that is to be newly wound, makes it thus possible in the manner described above to produce fiber coils 200 that are of high quality, because they are wound homogeneously and compactly, in a fully automatic, fast and cost-efficient manner.