Cylindrical carbon fiber reinforced part and manufacturing method thereof

Abstract

The present invention relates to a device, such as a machine component, comprising: a body having a substantially cylindrical shape of carbon fiber, wherein the carbon fibers are oriented in the longitudinal direction of the cylindrical shape, the body serving as a carrier body having a carrier surface; and at least one circumferential body of plastic, which is applied to the body by injection molding, the circumferential body being applied to at least a portion of the carrier surface. Furthermore, the present invention relates to a method for manufacturing the device, comprising: producing a substantially cylindrical shape of carbon fiber-reinforced material by pultrusion, wherein the carbon fibers are oriented substantially in the longitudinal direction of the cylindrical shape; and injection molding the plastic onto the cylindrical shape to obtain the circumferential body over at least a portion of the carrier surface.

Description

Technical Field

[0001] The invention relates to a device, such as a machine component, and a method for producing a machine component. Background Art

[0002] US6202557 discloses a device that describes a shaft body used as a roll in a papermaking printing press. Due to the large size and weight of such shafts, the shaft body is constructed from carbon-reinforced fiber in this application. Further described is the use of a winding process for producing a web of this material. Rather than functioning as a specific machine component in a string of components, the polyurethane cover described in US6202557 provides friction for moving the restraining material. Clearly, the shaft body comprises woven carbon fibers.

[0003] In EP2650101, pairs of rollers are described for the directional displacement of small plastic containers and have a similar function, i.e. a friction function, to obtain reliable continuous processing. Here, the rollers also comprise braided carbon fibers.

[0004] US5842711 describes how the components of a bicycle frame can be put together and assembled. More specifically, short frame rod segments are obtained by pultrusion of a material, for example containing carbon reinforced fibers. With regard to the couplings, it is mentioned that these are provided by overmolding.

[0005] It will be clear to those skilled in the art that these short rod sections comprise a braided structure of carbon reinforced fibers. This is the only way to prevent the rod components from breaking or tearing under the sudden movements and loads that occur during cycling, as the braided structure provides flexibility and resilience.

[0006] For rod segments having a similar structure, reference may also be made to US Pat. No. 5,318,742, in which fiber layers are continuously wound around an inner tube.

[0007] Another reference to a carrier component obtained by pultruding a carbon fiber woven plastic material and then providing a component on the carbon fiber woven plastic material by overmolding is found in "TECHNOLOGIES AND MANUFACTURING PROCESS" at epsilon-composite.com.

[0008] In this patent application, the following terms are mentioned and used: cylinder, cylinder, cylindrical shape, and cylindrical or cylindrical-shaped. As a reference to the meaning of these terms, reference is made to Kern and Bland, SOLID MENSURATION, 2nd edition, Wiley and Sons, 1948, page 32, which provides a general definition of a cylindrical surface. In the case of a specific cross-section to be selected and used, for example, but not exclusively, a circular, square, or rectangular cross-section, this will be explicitly indicated.

[0009] With respect to the technology for processes used in plastics processing, among such processes as injection molding, extrusion, pultrusion and overmolding, the following references are listed and explained below.

[0010] A general reference to this approach is described in Geoff Eckold, "Design and Manufacture of Composite Structures", 261-265, ISBN 00700189617.

[0011] More specifically, pultrusion is a continuous manufacturing process in which fibers (such as carbon fibers) that provide properties such as strength and stiffness are impregnated with a resin (known as a thermoset). After this impregnation, the fibers are pulled through a heated die. The die determines the final shape of the profile (for example, a cylinder). The resin cures in the die.

[0012] The profile is pulled through the die by a drawing unit and adjusted to the correct length with a saw.

[0013] Injection molding is described, among other processes, in "Materials Science of Polymers for Engineers," Hans Gardner Publications, 2nd ed., Tim Osswald, Georg Menges, 233-239, ISBN 1 56990 3484. Injection molding of plastics is a molding technique used for thermoplastics, thermosetting plastics, and metals with low melting points. In this process, the plastic is supplied in the form of granules or powder, melted to form a viscous mass, and then injected under high pressure into a mold whose cavity has the shape of the desired product. Upon cooling, the plastic solidifies, resulting in the desired product.

[0014] The term "overmolding" means applying plastic to an existing solid material part by injection molding.

[0015] For an overview of the types and properties of the many types of plastics and materials, please refer to the following literature:

[0016] For details on the groups of plastics, see “Kunststof- en Polymeerchemie” [“Plastic and Polymer Chemistry”], R van der Laan, ed. Bohn-Stafleu-VanLochum, 269289, ISBN 90 313 2896 0, Saechtling; “Kunststoff Taschenbuch”, Hanser Verlag, 25th edition, ISBN 3 446 164987; for the additives used in this technology, see Gächter, Müller, “Kunststoff Additive”, Hanser Verlag, 3rd edition, ISBN 3446 156275

[0017] The abbreviations used below can be found in the above references. In some places, TPE is used for thermoplastic elastomer and TPU is used for thermoplastic polyurethane, and TPU is considered to be a type of TPE.

[0018] DE102014004158 describes a load-transmitting assembly with gears that features a hollow plastic shaft with a second (metal or plastic) tube positioned within it. This tube has an interlocking section with a reduced diameter. During the manufacturing process, the plastic shaft is locally heated to achieve this diameter reduction.

[0019] DE 195 38 360 relates to a cardan shaft for a vehicle, which has a fiber-reinforced shaft on which two flanges are arranged by injection molding. Summary of the Invention

[0020] The present invention relates to:

[0021] A device, such as a machine component, in particular a component of an egg sorting machine, comprising:

[0022] a body having a substantially cylindrical shape of carbon fibers with the fibers in a longitudinal direction of the cylindrical shape, the body serving as a carrier body having a carrier surface; and

[0023] At least a single circumferential body of plastic is arranged on the main body by injection molding, the circumferential body being arranged on at least a portion of the carrier surface.

[0024] It has been found that such components, such as but not exclusively the shaft body, have similar mechanical characteristics to components used hitherto made essentially of steel, such as steel with a suitable plastic layer applied thereto. Steel shafts tend to deform slightly during intensive use.

[0025] In contrast, the material used according to the invention offers not only the great advantage of rapid production but also the possibility of rapid, required mechanical and dimensional adjustments.

[0026] In addition, their elastic material properties ensure better dimensional stability. This dimensional stability or shape retention property is critical, for example, in egg sorting machines, where intensive use can lead to loss of shape and therefore cracked eggs.

[0027] The machine components obtained in the above manner have great advantages in the selection of specifications requiring high precision.

[0028] Additionally, they have been found to have a suitable high degree of strength and to remain highly dimensionally stable over extended periods of use.

[0029] This method has been found to be cost-effective and efficient. Plastics that can be processed and applied with great advantage include, in particular, TPU, PBT, POM, PA and PVC.

[0030] Preferably, the cylindrical body (consisting essentially of carbon fibers) is completely embedded in the injection-molded material (i.e., completely surrounded by at least one circumferential body and optional intermediate spacers, wherein the corresponding injection-molded material, for example, forms a closed integral body around the body). This allows for improved food safety and hygiene. In particular, in food applications, since carbon fibers are not food-safe, loosening of the fibers (e.g., through abrasion) is unacceptable. By completely overmolding the carbon fibers, this can be prevented.

[0031] More specifically, the shaft with the circumferential body can be manufactured integrally in two consecutive runs, one run for the cylindrical shape and subsequently, one run for the circumferential body, with the result that, in an appropriate manner, fewer deviations occur in the desired dimensions and specifications.

[0032] Furthermore, it will be clear to the person skilled in the art that an industrial and rapid production is thereby achieved per se, and this has great economic benefits.

[0033] Furthermore, PBT, POM and PA are specified, which are further examples of thermoplastics, more particularly referred to as engineering plastics.

[0034] The invention also relates to a method for producing a device having a cylindrical shape, such as a hollow shaft serving as a carrier body having a carrier surface, the device being provided with at least a single circumferential body, the method comprising:

[0035] extruding to obtain a substantially cylindrical shape of carbon reinforced fiber material, wherein the carbon fibers are substantially in a longitudinal direction of the cylindrical shape; and

[0036] Plastic is injection-molded on the cylindrical shape for obtaining the circumferential body on at least part of the carrier surface.

[0037] Surprisingly, it has been found that the processability of the selected materials under the required process conditions is very suitable for the applications described in more detail below. In this regard, more particular mention is made of:

[0038] 3D directional injection molding has unexpectedly been suitably combined with the 1D configuration of the cylindrically shaped body; and

[0039] For typical injection molding times, the required temperatures and pressures have been found to be very suitable and usable. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In the following, the present invention is described in detail based on the accompanying drawings, in which:

[0041] Figure 1 A perspective view of a first exemplary embodiment of a machine component in which the present invention may be used is given;

[0042] Figure 2 Given the basis Figure 1 A perspective view of a machine component in which the present invention is used;

[0043] Figure 3 According to the prior art Figure 1 cross-section of a machine component;

[0044] Figure 4 According to the present invention, Figure 1 cross-section of a machine component;

[0045] Figure 5 A perspective view of a second exemplary embodiment of a machine component in which the present invention may be used is given;

[0046] Figure 6 The invention has been used according to Figure 5 a perspective view of the machine components; and

[0047] Figure 7Schematically shown is a top view of a portion of an egg sorting machine with rollers. DETAILED DESCRIPTION

[0048] Throughout the drawings, like reference numerals and designations will be used for like parts and details.

[0049] exist Figure 1 A perspective view of a sorting machine component, more specifically, an egg sorting machine, is shown. The figure shows a so-called roller shaft 1 having a circular cross-section. The roller shaft 1 comprises a hollow shaft body 2 made of a suitable type of steel and a circumferential body, particularly a diabolo-shaped roller body 3 (sometimes also referred to as an hourglass-shaped roller body 3), attached to the shaft body by injection molding. This shaft 1 is preferably connected at both ends (for example, in the described sorting machine) to two corresponding endless chains (or similar transmission elements), particularly for (electrical) drive purposes. Two consecutive roller bodies 3 on these roller shafts 1 can form an egg loading station. The array of circumferential bodies 3 can, for example, have identical shapes and dimensions.

[0050] Figure 7 An example of an array of roller shafts 1 having circumferential bodies (e.g., of an egg sorting machine) is shown. The roller shafts 1 may, for example, be part of an endless conveyor 30. Specifically, the shafts 1 extend parallel to one another and each is provided with an array of roller bodies 3, typically in the form of diabolo rollers, such that the roller bodies 3 of adjacent shafts define a nest for carrying products (e.g., eggs E). In particular, the conveying or transporting direction of the conveyor 30 is at right angles to the longitudinal direction of each of the roller shafts 1. Since the construction of such roller conveyors is well known, the drive devices, such as one or more electric motors, transmissions, etc., are not shown.

[0051] It is obvious to the person skilled in the art that the selection of a suitable plastic for the roller body 3 and the high precision of these machine components are required for the damage-free conveying of such a fragile product.

[0052] However, it has been found that the characteristics of these roller shafts 1 with roller bodies 3 change under intensive use including regular thorough chemical cleaning. It has been verified that the shaft bodies bend to some extent and the roller bodies show wear due to their intensive use and cleaning.

[0053] Figure 2 A perspective view of a shaft of the same type is shown, for example a roller shaft 1, wherein the shaft body is essentially manufactured by pultrusion of a carbon fiber material ( Figure 2 The shaft body of the roller shaft 1 is particularly shown.) More specifically, a pultrusion process is performed such that the carbon fibers are substantially along the shaft direction and embedded in a matrix (or filler) of epoxy resin.

[0054] This material combination has suitable mechanical properties for this machine component, particularly with regard to weight, wear, and flexibility, and is more suitable than the steel used to date. The percentage of fibers in the matrix is ​​between 50% and 80%. The fiber material is of a type commonly used, for example from Mitsubishi, and has a fiber strength of more than 4000 MPa.

[0055] from Figure 2 It can be seen that the shaft body of the roller shaft has, for example, a constant outer diameter (viewed in the longitudinal direction of the shaft). In other words, the shaft body preferably does not have any local portions with reduced diameter.

[0056] exist Figure 3 In FIG, a cross section of a portion of a roller shaft 1 having a circular cross section is shown, according to the prior art, on which a shaft cover 5 and a roller body 3 are provided by injection molding. More specifically, the steel shaft body has been overmolded with a first cover part 51 of PA, each of which has two collar edges 52.

[0057] Then, by injection molding, the roller main body 3 connecting these has been provided, and as described above, the roller main body 3 is diabolo-shaped. These roller main bodies 3 are formed of a mixture of PVC and NBR.

[0058] Figure 4 A portion of an apparatus according to an exemplary embodiment of the invention is shown. The apparatus comprises, for example, parts of a machine, in particular parts of an egg sorting machine (see Figure 7 ), which includes:

[0059] a body having a substantially cylindrical shape of carbon fibers in a longitudinal direction of the cylindrical shape, the body serving as a carrier body having a carrier surface; and

[0060] At least a single circumferential body 10 of plastic is provided by injection molding on the main body 20, the circumferential body 10 being arranged on at least part of the carrier surface.

[0061] exist Figure 4 In particular, a cross section of a portion of a roller shaft 1 having a circular cross section is shown, on which a covering portion M is provided (at least in Figure 2 The roller body is essentially manufactured by pultrusion of a carbon fiber material (on the shaft body shown), and the roller body is constructed as a single piece. The machine component shown here is manufactured according to the present invention, wherein the shaft preferably comprises an epoxy resin matrix, the carbon fibers are arranged along the length of the shaft body shown, and the overmolding is essentially performed with a thermoplastic, preferably TPU. This material combination has proven to be very suitable.

[0062] It has been found that, for example, TPU adheres very well to carbon fibers (fibers in the longitudinal direction), so, for example, there is no need to (locally) reduce the diameter of the carrier tube for proper adhesion. This is a significant advantage, as it means that the carrier tube does not need to be heated (and deformed) during the injection molding step, thereby avoiding weakening of the tube. In particular, the injection molding step is performed on a non-heated ('cold') shaft body (i.e., the cover with the roller body and optional spacers 4 is provided on the formed shaft body).

[0063] In particular, the roller bodies together form a circumferential body and are connected together, for example, by an integral intermediate cover M (see Figure 4 ). In other words, the cover portion M and the roller body are preferably manufactured integrally, ie in one piece (in the same injection molding step), and in particular, are integrally provided on the shaft body which has been formed by pultrusion. Figure 4 As can be seen in FIG. 4 , the spacers 4 of the cover M can be arranged between (adjacent) circumferential bodies 10 and can, for example, be manufactured integrally with those circumferential bodies (in the same injection-molding step).

[0064] exist Figure 5 shows a perspective view of a second exemplary embodiment of a machine component that can utilize the present invention. More specifically, the figure shows a tube 100 having a tubular body 101 with a square cross-section. This tubular body is obtained by pultrusion of a carbon fiber material in the same manner as described above. In application, this tube will again serve as a carrier body, onto which other components are applied by injection molding (also known as overmolding).

[0065] from Figure 5 As can be seen in FIG, the tubular shape has, for example, a constant-angle outer circumference viewed in the longitudinal direction of the tube (ie the tube is not provided with any local portions of reduced diameter).

[0066] More specifically, in Figure 6 Shown in Figure 5 , wherein the machine components 102-104 are provided on the tube 100 by injection molding (overmolding), more specifically, the tube 100 has six fixing blocks for the gripper halves for transferring eggs, as described, for example, in NL 1029748. Previously, after each such block was squeezed, these blocks were slid continuously on the steel tube.

[0067] It is clear to those skilled in the art that the precision of each individual piece needs to be very high, as even small deviations can lead to incorrect configuration in the usual manner, resulting in eggs breaking during processing. In addition, this manufacturing method is very time-consuming.

[0068] In this Figure 6The six aforementioned fixing blocks 102a-102f are shown, along with a similar number of grids 103a-103f on top, shown here. These grids have snap-fitting edges for snap-fitting the clamp halves (not shown here), and a similar number of spacers 104a-104f between these fixing blocks 102a-102f, which ensure the relative distance between the clamps. According to the present invention, these previously discrete components are now integrally formed by injection molding (overmolding) onto the tubular body 101. In this application, POM is used as the plastic, in large part.

[0069] Other thermoplastics that are generally known and particularly suitable for the applications described herein are, for example, but not limited to, TPE, TPS, TPO, TPV, TPC, TPA, TPZ, SBS, TPEE, PE derivatives, PBT, POM, PA, (liquid) silicone rubber, and several rubber compounds such as SBR, IR, IRR, NR, CSM, EPM, VMQ, AU or ACM. Furthermore, as is known to those skilled in the art, preferably Shore A and Shore D hardnesses are applied, which are established when these materials are ready for use, i.e., 24 hours after the end of the injection molding process.

[0070] Obviously, all possible surface profiles can be chosen, with a closed circumference (closed description line), represented in the following in a random and non-limiting manner, such as an axis with an elliptical cross section, an axis with a rectangular cross section, with smaller or more curved or hemispherical surfaces, etc.

[0071] It is clear to a person skilled in the art that such a profile has many applications in machine construction, both in machine construction as described above for egg sorting machines and in the automotive industry, or further similar transport devices, see for example the products shown at www.ptonline.com, such as airbag components.

[0072] Furthermore, the present invention provides a method for producing a device having a cylindrical shape, for example a machine component serving as a carrier body having a carrier surface, the carrier body being provided with at least one individual circumferential body, the method comprising:

[0073] extruding to obtain a substantially cylindrical shape of carbon reinforced fiber material, wherein the carbon fibers are substantially in a longitudinal direction of the cylindrical shape; and

[0074] Injection moulding of plastic is performed on said cylindrical shape for obtaining said circumferential body on at least part of said carrier surface.

[0075] Injection moulding, more particularly the overmoulding of carrier bodies is generally known (see the references specified above). It has been found that an arrangement can be used which allows automation.

[0076] In particular, for injection molding the above-mentioned plastic on a cylindrical shape, an injection angle α relative to the longitudinal direction is selected, where 0°≤α≤90°, where α is in degrees, and the injection angle α is preferably less than 90°, for example in the range of 0°-70°, preferably in the range of 0°-45°.

[0077] It has been found that deformation of the cylindrical shape can be avoided or reduced by using a spray angle of less than 90 degrees, in particular at a spray angle of less than about 70 degrees, and more particularly at an angle of less than 45 degrees. In particular, the cylindrical shape is not locally deformed (e.g., by heating), and the use of reinforcing inserts can be avoided.

[0078] In another embodiment, for injection molding the above-mentioned plastic on a cylindrical shape, a fluid pressure p is selected to be 100≤p≤1000, where p is in bar.

[0079] In yet another embodiment, to injection mold the above-mentioned plastic on a cylindrical shape, the injection molding operation temperature T is selected to be 100≤T≤300, where T is in degrees Celsius.

[0080] It is obvious to a person skilled in the art that the invention is not limited to the described exemplary embodiments. Various modifications are possible within the scope of the invention as described in the claims.

Claims

1. A machine component for an egg sorting machine, comprising: Main body (20; 101), having a cylindrical shape of carbon fibers, wherein the carbon fibers are in a longitudinal direction of the cylindrical shape, the body serving as a carrier body having a carrier surface; as well as Adjacent circumferential bodies (10; 102-104) of plastic, arranged on said body (20; 101) by injection molding, said circumferential bodies (10; 102-104) being arranged on at least part of said carrier surface, Wherein, on the carrier body (20; 101), spacers (4; 104a-104f) are arranged between adjacent circumferential bodies by injection molding.

2. The machine component according to claim 1, wherein The carrier surface is provided with a shaft covering (M) by injection moulding, the shaft covering having an array of circumferential bodies (10; 102-104).

3. Machine component according to any one of the preceding claims, characterized in that The plastics include thermoplastics.

4. The machine component according to claim 3, characterized in that The thermoplastic includes TPE.

5. The machine component according to claim 3, characterized in that The thermoplastic plastic includes PBT, POM, PA, or PVC.

6. The machine component according to claim 3, characterized in that The machine component comprises a hollow cylindrical shaft.

7. The machine component according to claim 3, characterized in that Each circumferential body comprises a diabolo-shaped roller element.

8. The machine component according to claim 1, characterized in that The machine component comprises a hollow tube (101) having a square cross section.

9. The machine component according to claim 1, characterized in that The machine component comprises a hollow tube of rectangular cross-section.

10. A sorting machine for eggs, comprising at least one device, said device comprising: Main body (20; 101), having a cylindrical shape of carbon fibers, wherein the carbon fibers are in a longitudinal direction of the cylindrical shape, the body serving as a carrier body having a carrier surface; as well as an array of circumferential bodies (10; 102-104) of plastic, provided on said body (20; 101) by injection moulding, said circumferential bodies being provided on at least part of said carrier surface, Therein, the carrier body (20; 101) is embedded in a covering portion comprising the array of circumferential bodies (10; 102-104).

11. The sorting machine according to claim 10, wherein: Each device includes a hollow shaft body having a diabolo-shaped roller body thereon.

12. The sorting machine according to claim 11, wherein: The spacers of the covering portion extend between the roller bodies.

13. The sorting machine according to claim 10, wherein: The carrier body is completely surrounded by the array of circumferential bodies and optional intermediate spacers.

14. The sorting machine according to claim 10, wherein: The sorting machine comprises an array of roller shafts (1) having circumferential bodies, wherein the roller shafts (1) extend parallel to each other and are each provided with an array of diabolo-shaped rollers such that the roller bodies of adjacent shafts define nests for carrying eggs (E).

15. A method for producing a device having a cylindrical shape, the device being a machine component of a sorting machine for eggs, serving as a carrier body (20; 101 ), the device is provided with at least one single circumferential body (10; 102-104), the method comprising: Produced as a cylindrical shape of carbon reinforced fiber material using pultrusion, wherein the carbon fibers are in a longitudinal direction of the cylindrical shape; and injection molding plastic on said cylindrical shape for obtaining a circumferential body on at least part of said carrier surface, Wherein, on the carrier body (20; 101), spacers (4; 104a-104f) are arranged between adjacent circumferential bodies by injection molding.

16. The method according to claim 15, characterized in that The plastic includes thermoplastics.

17. The method according to claim 16, characterized in that The thermoplastic includes TPE.

18. The method according to claim 16, characterized in that The thermoplastic plastic includes PBT, POM, PA, or PVC.

19. The method according to claim 16, wherein An injection angle α is selected to injection mold the thermoplastic onto the cylindrical shape, the injection angle α being 0°≤α≤90° relative to the longitudinal direction, the injection angle α being in degrees.

20. The method according to claim 15, wherein For injection molding of the plastic onto the cylindrical shape, the fluid pressure p is selected to be 50≤p≤1000, where p is in bar.

21. The method according to claim 15, wherein For injection molding the plastic onto the cylindrical shape, the injection molding operation temperature T is selected to be 10≤T≤300, where T is in degrees Celsius.

22. The method according to claim 15, wherein The cylindrical shape manufactured by pultrusion has a constant outer circumference viewed in the longitudinal direction of the cylindrical shape and does not include a portion with reduced diameter, wherein the cylindrical shape manufactured by pultrusion maintains a constant outer circumference during injection molding of the circumferential body thereon.

23. The method according to claim 15, characterized in that Said cylindrical shape, manufactured by pultrusion, is provided with a shaft covering (M) with a circumferential body (10; 102-104).

24. The method according to claim 15, wherein The cylindrical shape manufactured by pultrusion is not deformed and / or heated before and during injection molding of the plastic onto the cylindrical shape.

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