Wheel and drive shaft for a bicycle

Abstract

The invention relates to a wheel (1) for a bicycle, comprising a rim element (2), a plurality of pressure spoke elements (3) and a hub element (4) made of a thermoplastic plastics material, with the proviso that the rim element (2) is formed in a single piece together with the pressure spoke elements (3) and together with the hub element (4), wherein a wheel hollow body (5) comprising a closed wheel wall (6) is formed, wherein at least the rim element (2) and the pressure spoke elements (3) are hollow, and wherein the single-piece form of the wheel (1) is produced by means of rotational moulding in a rotational moulding die that can be heated externally; and comprising a drive shaft for the wheel.

Description

[0001] Wheel and drive shaft for a bicycle

[0002] The invention relates to a wheel for a bicycle, comprising a rim element, a plurality of pressure spoke elements and a hub element made of a thermoplastic material, with the proviso that the rim element is formed in one piece together with the pressure spoke elements and together with the hub element.

[0003] A common bicycle wheel, constructed from a multi-part rim element and standard spokes, derives its strength from the high tensile strength of the standard spokes. These are installed with preload and are usually made of steel. However, they would bend even under low compressive forces.

[0004] This is to be distinguished from a wheel with compression spoke elements, which have a thicker cross-section, such as the compression spokes on earlier vehicles with wooden wheels. In principle, a compression spoke element can absorb a compressive force introduced by the rim element and transmit it to the hub element. This one-piece wheel is equipped with compression spoke elements that are subjected to compression during operation.

[0005] Compared to steel and aluminum, thermoplastics exhibit lower strength as a material for a wheel. The modulus of elasticity is lower than that of steel and aluminum. Likewise, the dimensional rigidity of thermoplastics is lower.

[0006] A common plastic wheel with compression spokes is a so-called composite wheel. This is typically made of fiber-reinforced plastic, reinforced with loose fiber components, for example, or with a fiber fabric, as in a carbon wheel. During the manufacturing process, stresses and warping can occur. The production of a composite wheel is complex and expensive.

[0007] The invention is based on the object of proposing an impeller made of a thermoplastic material which is simpler in construction and can be produced cost-effectively.

[0008] According to the invention, the object is achieved in that a hollow wheel body is formed with a closed wheel wall, wherein at least the rim element and the pressure spoke elements are hollow, and in that the one-piece design of the wheel is produced by means of rotational molding in an externally heatable rotational molding tool.

[0009] The rim element of the hollow wheel body is designed so that a conventional bicycle tire can be mounted. For the purposes of the invention, a conventional type includes a tubular tire or a tubeless tire, both of which are inflated with air. Furthermore, the tire type that uses a filling material other than air, such as a foam that exhibits a suitable resilience when deformed, is also meant. The rim element has two rim flanks and a rim base. Rim flanges are expediently provided on the rim flanks to provide support for a bicycle tire.

[0010] For rotational molding, the thermoplastic material is filled in powder form into the rotational molding tool, which is closed all around for the molding process. The rotational molding tool has an inner wall that forms a negative of the shape to be molded. The rotational molding tool is expediently designed as a permanent mold, which is usually made of metal, preferably aluminum. For the molding process, the rotational molding tool can be rotated about at least one axis and is heated from the outside. The plastic powder melts within it and can be distributed over the inner wall in a viscous state as a melt. Finally, the melt solidifies on the inner wall of the rotational molding tool and can then be removed as a finished hollow body after the rotational molding tool has been opened.

[0011] The hollow wheel body for a bicycle wheel requires a precisely shaped form. The inventor has discovered that it is advantageous for a wheel if plastic material, which expands in the tool during solidification, can expand freely inward into the hollow rotational molding tool. In this way, a stress-relieved wheel can be provided that has the dimensional accuracy and stability required for a bicycle and warps little during and after production. In addition, the rotational-molded wheel is seamless because of its one-piece construction, which promotes its strength.

[0012] The impeller hollow body expediently has areas with different wall thicknesses of the wheel wall. In this way, the impeller hollow body can be prepared so that areas of the wheel wall which are particularly stressed during ferry operation are reinforced with more material in order to counteract cracks and fractures in these areas. The areas of the wheel wall with different wall thicknesses are created by a different heat supply from the outside to the rotational forming tool. In more heavily heated areas the powder melts more quickly and in the course of the process a greater wall thickness can be built up to provide the necessary strength. Surprisingly, it was found that even for an impeller hollow body with different wall thicknesses of the wheel wall a low stress level is possible, which can provide the required dimensional accuracy.

[0013] It is beneficial if the thermoplastic material for the wheel wall is selected from one of the following plastics: polypropylene (PP), preferably polyethylene (PE), particularly preferably high-density polyethylene (HDPE). Economical cycles already exist for the types mentioned, which can recycle these plastics and make them available in a form ready for reuse. For this purpose, they are collected, for example, from the sea and in agriculture. They occur in fishing nets, trawl nets, nets for aquaculture or as net wraps for tying straw bales, and also as scaffolding nets to protect road users. The proposed impeller greatly facilitates the recovery of such types directly from everyday products, which are then returned to the cycle without first polluting the environment.

[0014] It is very beneficial for reuse if the thermoplastic is fiber-free. For the purposes of the present invention, a thermoplastic is also considered fiber-free if it is sufficiently low in fibers to be processed in such a way that it is suitable for rotational molding.

[0015] In addition, a wheel also achieves the underlying problem if each pressure spoke element is rooted at the hub element and forms a trunk-shaped base, wherein the trunk-shaped base of at least one pressure spoke element extends away from the hub element in the direction of the rim element and is divided into at least two branch elements, and wherein at least one branch element is connected to the rim element.

[0016] During use, a vertical load is exerted on the bicycle and as a result the wheel tends to flatten slightly when it comes into contact with the road surface. A compressive force is exerted from below by the rim element, from the direction of the road surface, on the pressure spoke element. The pressure spoke element transfers this compressive force all the way to the hub element. When the wheel rotates in ferry operation, it is useful if one of the branch elements reaches and passes through the lowest pivot point before the trunk-shaped base, or rather its center line, passes through the lowest pivot point. As soon as the center line is at the lowest pivot point, the branch elements are arranged symmetrically so that both absorb a portion of the compressive force acting from below and combine it into the trunk-shaped base.

[0017] The design was calculated using specially programmed software that takes natural growth processes into account. The inventor discovered that it was useful for the wheel to provide a structure that follows a natural model and is stable, like the trunk and branches of a tree. The trunk-shaped base can be arranged radially to the hub element. The branch elements simply branch off from the trunk-shaped base to form a V-shaped arrangement of branch elements towards the rim element. It was also found to be useful if the V-shaped arrangement of the branch elements was symmetrical.

[0018] The rim element preferably has a nominal rim diameter in the range of 150 mm to 650 mm. The nominal rim diameter is defined as the diameter measured at the bottom corners of the rim base. For example, a 10" wheel has a nominal rim diameter of 152 mm according to ETRTO (European Tire and Rim Expert Organization), and a 28" wheel typically has a nominal rim diameter of 622 mm according to ETRTO.

[0019] The two branch elements and the trunk-shaped base of the pressure spoke element expediently meet in a node, the node being a circle diameter which is arranged coaxially to the hub element, the size of the circle diameter being in the range of 0.4 to 0.6 times, based on the outer diameter of the rim element.

[0020] Preferably, the hub element has a hollow cylindrical hub sleeve.

[0021] Furthermore, an impeller also solves the underlying problem if the hub element has a hollow cylindrical hub sleeve whose inner diameter is at least as large as the length of the hub sleeve in its axial direction.

[0022] This measure is based on the inventor's discovery that a relatively large diameter of the hub shell in relation to the diameter of the wheel increases the strength of the wheel. The pressure spoke elements are shorter as the radius of the hub shell increases. As a guideline for the diameter of the hub shell, one can assume how large a drive shaft for the wheel must be, if this drive shaft is also made of plastic.

[0023] After consideration, it is assumed that a suitable measure for the hollow cylindrical diameter of the hub sleeve is in the range of a factor of 1.0 to 2.0, based on the length of the hub sleeve.

[0024] Apart from the length of the hub shell, the inventor assumes a hollow cylindrical diameter of the hub shell in the range of 90 mm to 140 mm for an exemplary 28" wheel which has an outer diameter of 622 mm.

[0025] In addition, the hollow cylindrical hub sleeve of the hub element is suitably designed to cooperate either with a drive shaft or with a fixed wheel axle.

[0026] At least one means is advantageously provided on the hub element by means of which a torque can be transmitted.

[0027] Simply put, the means for transmitting the torque comprises a plurality of threaded holes arranged on one edge of the hub element and distributed circumferentially around the hub shell.

[0028] The means for absorbing torque is advantageously adapted to attach a drive shaft to the hub element and / or to attach a brake disc to the hub element. The proposed internal threads on the edge of the hub element can be arranged in a metal element, wherein the metal element is expediently integrated into the thermoplastic material of the impeller hollow body.

[0029] It is helpful if the wheel is equipped with a data storage element, preferably an RFID storage element. Preferably, this can store material information and / or data relating to the wheel's production, particularly regarding the plastic material used. When a bicycle wheel returns to the commercial cycle at the end of its service life, stored information can help process and reuse the plastic as a pure raw material.

[0030] In a preferred embodiment, six pressure spoke elements are provided for the proposed wheel.

[0031] The impeller expediently has an envelope volume in a range of 3.5 liters to 5 liters, preferably in the range of

[0032] 3.8 liters to 4.4 liters and particularly preferably in the range of 4 liters to 4.2 liters.

[0033] The envelope volume of the wheel within the meaning of the invention is understood to be the volume of the outer surface of the wheel (without bicycle tire), with the proviso that all existing openings are interpreted as closed surface areas and are assigned to the outer surface, e.g., each opening for a hose valve is interpreted as a closed surface area.

[0034] Furthermore, it is advantageous, either on its own or in combination with the mentioned envelope volume, if the impeller has a weight in the range of 1.3 kg to 2.2 kg, preferably in the range of 1.6 kg to

[0035] 1.9 kg and particularly preferably in the range of 1.7 kg to 1.8 kg.

[0036] The impeller has a specific weight in the range of 0.26 kg / liter to 0.63 kg / liter relative to its envelope volume.

[0037] The invention further includes a drive shaft for the previously proposed running wheels. The drive shaft is advantageously designed for single-sided mounting on a bicycle frame, preferably a single-sided rear wheel carrier of a bicycle frame.

[0038] A gear element is expediently arranged on the drive shaft, which can interact with a drive means of a bicycle.

[0039] Advantageously, the gear element comprises a pinion for a bicycle chain or a toothed pulley for a toothed belt or a gear for a drive shaft.

[0040] Advantageously, the drive shaft comprises two shaft elements which are arranged in alignment and connectable.

[0041] It is advantageous if one shaft element is designed as a wheel carrier shaft element and the other as a support shaft element.

[0042] Both shaft elements advantageously comprise complementary connecting means designed to transmit a rotary motion in at least one direction of rotation between the two shaft elements. The connecting means can be complementary threads or complementary profiles, such as a splined shaft profile and a splined hub profile.

[0043] The gear element is preferably arranged on the wheel carrier shaft element. The wheel carrier shaft element can be provided with a carrier element to which a gear element can be mounted in a rotationally fixed manner.

[0044] Furthermore, the gear element can be integrated in one piece into the drive shaft or into one of the shaft elements, preferably into the wheel carrier shaft element. Bicycle component from the group: wheel and drive shaft, comprising a one-piece hollow body with a component wall enclosing its cavity, wherein the component wall of the hollow body is produced in a closed forming tool from a thermoplastic plastic, wherein the component wall has a one-piece design which is produced by means of rotational molding in an externally heatable forming tool designed for rotational molding, with the additional proviso that a foam is arranged in the cavity, and that the foam extends as a foam layer over the inside of the component wall or completely fills the cavity.

[0045] Finally, a bicycle component from the group: wheel and drive shaft is proposed. This bicycle component comprises a one-piece hollow body with a component wall enclosing its cavity, wherein the component wall of the hollow body is produced in a closed forming tool from a thermoplastic and is of one piece, which is produced by means of rotational molding in an externally heatable forming tool intended for rotational molding, with the additional proviso that a foam is arranged in the cavity and that the foam extends as a foam layer over the inside of the component wall or completely fills the cavity.

[0046] The foaming process is advantageously carried out inside the cavity. Preferably, the foaming process is carried out while the rotational molding of the component wall is still in progress using molten thermoplastic for the rotational molding of the component wall. A starting material for the foam is filled into the resulting cavity through at least one suitable filling agent provided on the molding tool, in order to foam therein. Simply, the starting material is filled into the same opening in the molding tool as the thermoplastic for the component wall. A feed tube can be used which can be inserted into the molding tool. It can be inserted so deeply that it penetrates the layer of molten thermoplastic that has already formed on the inside of the molding tool.The foam starting material can be easily filled while the rotational movement of the forming tool is stopped. The rotational movement of the forming tool is not just a circular movement, but advantageously a complex three-dimensional movement in space. To fill the foam starting material, it is possible, for example, to stop one component of the complex movement in order to then insert the feed tube into the filling means of the forming tool and fill the foam starting material into the remaining cavity.

[0047] In principle, the foaming process can be a physical process or the foaming process can be based on a chemical reaction. The starting material of the foam is expediently filled in the form of granules through the filling means of the forming tool into the resulting cavity. For chemical foaming, the granules of the starting material can simply be provided with a blowing agent. The blowing agent is preferably designed so that it can evaporate when heat is applied. If the starting material also melts as a result of the heat application, the evaporated blowing agent can foam the molten starting material. The invention is illustrated below by way of example in a drawing and described in detail with reference to several figures. They show:

[0048] Fig. 1 is a perspective view of an impeller according to the invention,

[0049] Fig. 2 is a side view of the impeller according to Fig. 1,

[0050] Fig. 3 a cross-section according to the section line III - III noted in Fig. 2,

[0051] Fig. 4 is an enlarged view of section IV, as noted in Fig. 3,

[0052] Fig. 5 is a partial sectional view along the section line V - V shown in Fig. 2,

[0053] Fig. 6 a drive shaft according to the invention in cross section,

[0054] Fig. 7 is a representation of the impeller according to Fig. 5 in the mounted state on the drive shaft according to Fig. 6,

[0055] Fig. 8 is an enlarged partial side view of the impeller with mounted drive shaft according to Fig. 7,

[0056] Fig. 9 a partial sectional view according to section IX - IX, as noted in Fig.2

[0057] Fig. 10 shows an alternative embodiment of the wheel based on an enlarged view of a section, such as the section in Fig. 4, as a bicycle component with a rotationally molded hollow body and a foam filling,

[0058] Fig. 11 shows a further alternative embodiment of the wheel in a partial sectional view, like that in Fig. 5, as a bicycle component with a rotationally molded hollow body with a layer of foam.

[0059] Fig. 1 shows a wheel 1 according to the invention in a perspective view. The wheel 1 comprises as components a rim element 2, several pressure spoke elements 3 and a hub element 4. The wheel 1 as a whole, i.e. comprising all components, is formed in one piece and is made of a thermoplastic material. It is designed as a hollow wheel body 5 with a closed wheel wall 6. In the example, the rim element 2, the pressure spoke elements 3 and also the hub element 4 are hollow in such a way that a common cavity 7 is formed. The wheel wall 6 is seamless. The one-piece design of the wheel 1 is produced by means of rotational molding in an externally heatable rotational molding tool.

[0060] The pressure spoke elements 3 in particular have a special structure. Each pressure spoke element 3 is rooted with a trunk-shaped base 3a on the hub element 4, and there are a total of six pressure spoke elements 3. They extend in the radial direction from the hub element 4 in the direction of the rim element 2. Each pressure spoke element 3 is divided symmetrically into two branch elements 3b and 3c, so that a total of twelve branch elements are connected to the rim element 2. The proposed structure follows the natural model of a tree with a trunk and branches in order to provide improved stability. The symmetrically arranged branch elements 3b / 3c are arranged in a V-shape to one another and the two ends of the V-shape are connected to the rim element 2.

[0061] The impeller shown here has an envelope volume of 4.1 liters with a tolerance of ±0.1 liters. Its weight ranges from 1.6 kg to 1.9 kg.

[0062] The rim element 2 is designed to accommodate a conventional bicycle tire, such as a pneumatic tire in the form of a tubular tire or a tubeless tire. Bicycle tires with a filling other than air, such as foam, can also be used. It is a hollow-chamber rim element with a deep rim base 8 and rim flanks 9 and 10, each of which has a rim flange (not shown) for securing a bicycle tire to the rim cross-section.

[0063] Furthermore, the hub element 4 represents a special structure of this impeller 1 because the hub element 4 is designed as a large hollow cylindrical hub sleeve 11, the inner diameter D of which is at least as large as the length L of the hub sleeve 11 in its axial direction. In the present example, the inner diameter D of the hub sleeve is 120 mm and its length L is 77 mm. In this way, the hub sleeve 11 is designed to optionally accommodate either a drive shaft, which is preferably made of plastic, or to accommodate bearing elements for supporting the impeller 1 on a fixed wheel axle, which is preferably made of plastic. Both a wheel axle and a drive shaft require a larger cross-section than a conventional wheel axle or drive shaft made of steel or aluminum.The inner diameter D of the hub sleeve 11 is therefore particularly oriented towards the diameter required by a drive shaft made of plastic. Furthermore, it is taken into account that a drive shaft can be designed so that it is supported on one side, which means that the impeller 1 is freely accessible from one side and can be mounted like a car wheel. In the present example, the inner diameter D of the hub sleeve 11 is a factor of 0.7 larger than the length L of the hub sleeve 11 in its axial direction.

[0064] Fig. 2 shows the wheel 1 according to Fig. 1 as a side view. The stable structure of each pressure spoke 3 is clearly visible. Six pressure spokes 3 are evenly distributed around the circumference of the hub element 4 and extend with their trunk-shaped base 3a radially outwards to a node 12, at which they divide into the two branch elements 3b and 3c. In this way, a total of twelve branch elements merge into the rim element 2. The node lies on a circular diameter K which in the example is half the size of the nominal rim diameter DF.

[0065] An RFID storage element 5a is provided on the hollow wheel body 5 to store information about the wheel 1, in particular about the plastic material used. When a bicycle wheel returns to the economic material cycle at the end of its service life, stored information can help process the plastic as a pure raw material for reuse.

[0066] Two adjacent pressure spoke elements 3, together with a section of the rim element 2 and a section of the hub element 4, form a large through-opening 13. In total, there are six large through-openings 13 on the wheel 1. In addition, the two branch elements 3b and 3c of a pressure spoke element 3, together with a section of the rim element 2, each form a small through-opening 14, thus likewise forming six small through-openings for the entire wheel 1. In addition to the stability of the structure, this results in an aesthetically pleasing design of the wheel 1. Fig. 3 shows a cross-section according to the section line III-III. The pressure spoke element 3 is cut perpendicular to its radial extent and the section line is arranged at a slight angle with respect to the longitudinal extent of the branch elements 3b and 3c.

[0067] The pressure spoke element 3 is shown enlarged in Fig. 4. The wall thickness t is noted on the hatched cross-section of the pressure spoke element 3. The hatched cross-section forms the cross-sectional area of ​​the pressure spoke element 3 which, according to the theory of strength, influences the strength. The cross-section is hexagonal in design, as an irregular hexagon with different side lengths. The sides which are aligned in the axial direction are longer than the sides of the hexagonal cross-section which are arranged parallel to the running direction of the impeller. The so-called area moment of inertia of such a cross-sectional area relates to how great the resistance of this cross-sectional area is to external deformation. The shape of the hatched cross-sectional area shown here has proven to be useful for carrying a static vertical load which acts on an impeller 1.Furthermore, the hatched cross-sectional area is useful for transmitting torque. On the one hand, a torque for driving, if the wheel 1, as the driven wheel 1, must transmit torque to a roadway, or for transmitting a braking torque if a braking torque is transmitted via the rim element 2 to the hub element 4, for example, because a disc brake is provided on the hub element 4.

[0068] Fig. 5 is a partial sectional view of the wheel 1 taken along the line V-V as indicated in Fig. 2. The section passes through the stem-shaped base 3a of the pressure spoke element 3 and shows the cross-section of the rim element 2. The nominal rim diameter DF is also indicated. Furthermore, Fig. 5 shows threaded holes 15 and 16 with internal threads which are provided as means 17 for absorbing a torque. As best seen in Fig. 8, these are two of a total of six threaded holes which are evenly spaced around an edge 18 of the hub element 4 for connecting the wheel 1 to a drive shaft, for example. Alternatively, a brake disc can be attached to the wheel 1 by means of these threaded holes 15 / 16.

[0069] In the present example, the threaded holes 15 / 16 are arranged in an annular aluminum element 19 which has been integrated into the thermoplastic material of the impeller hollow body 5 by means of rotational molding.

[0070] Fig. 6 shows a cross-section of a drive shaft 20 according to the invention. It is designed for one-sided mounting on a bicycle frame, preferably a one-sided rear wheel carrier of a bicycle frame. The drive shaft 20 comprises two shaft elements 21 and 22, which are aligned and connectable to one another. One shaft element 21 is designed as a wheel carrier shaft element 23, and the other as a support shaft element 24.

[0071] The wheel carrier shaft element 23 has a cylindrical wheel carrier surface 25, which carries an impeller according to the invention, which is indicated in Fig. 6 as a dashed line. The impeller sits with the hub sleeve of its hub element on the cylindrical wheel carrier surface 25. Furthermore, the wheel carrier shaft element 23 comprises a bearing shoulder 26 for a rolling bearing, which is also indicated as a dashed line. The rolling bearing has an inner ring, which can be mounted on the bearing shoulder 26.

[0072] During operation, the inner ring rotates together with the drive shaft 20 and the impeller 1 shown in dashed lines. The corresponding outer ring of the rolling bearing is fixedly arranged in a bicycle frame when assembled. Furthermore, a gear element 27 is provided, which in the present example is arranged on the wheel carrier shaft element 23. It is designed as a toothed pulley and serves for a toothed belt that can transmit a drive movement to the drive shaft 20.

[0073] The toothed disk 28 is non-rotatably connected to the wheel carrier shaft element 23 and is replaceable. Alternatively, the gear element 27 can be integrated in one piece with the wheel carrier shaft element 23 of the drive shaft 20.

[0074] Between the bearing shoulder 26 and the wheel carrier surface 25 of the wheel carrier shaft element 23 there is a flange 29 which has through holes 30 for screws. The through holes 30 serve to fasten the drive shaft 20 to the hub element 4 of the impeller 1 and enable torque to be transmitted from the drive shaft 20 to the impeller 1 for driving purposes or in the opposite direction to achieve a braking effect, for example with a brake disc (not shown). The flange 29 is provided with a total of six through holes 30 which are evenly distributed around the circumference of the flange 29. The arrangement of the six through holes 30 corresponds to the hole pattern of the six threaded holes provided on the edge 18 of the hub element 4 of the impeller 1.

[0075] The support shaft element 24 has a cylindrical bearing seat 31 for a rolling bearing. This rolling bearing is also indicated by a dashed line in Fig. 6. It also has an inner ring, which is arranged on the bearing seat 31 of the support shaft element 24 and rotates during operation together with the drive shaft 20 and the wheel 1. An associated outer ring of this rolling bearing is then also arranged stationary in a bicycle frame.

[0076] The wheel carrier shaft element 23 is connected to the support shaft element 24. The two shaft elements have complementary profiles as complementary connecting means, which enable torque transmission. The wheel carrier shaft element 23 is provided with a splined shaft profile 32 and the support shaft element 24 with a matching hub profile 33. Furthermore, the wheel carrier shaft element 23 and the support shaft element 24 are each provided with a central through-opening 34 and 35 respectively. When joined together, the through-openings 34 and 35 are arranged coaxially and can accommodate a screw connection (not shown). By means of the screw connection comprising a through-hole and a nut, the two shaft elements 20 and 21 can be connected to one another in the axial direction and secured.

[0077] Fig. 7 shows a section of the impeller 1 according to the invention, as in Fig. 5, but in the mounted state on a drive shaft 20 according to Fig. 6. The flange 29 of the wheel carrier shaft element 23 is fastened to the impeller 1 with screws 36 and 37. The screws 36 and 37 are inserted into the through holes 30 of the flange 29 and are screwed into the threaded holes 15 and 16, respectively, on the edge 18 of the hub element 4, thus enabling the transmission of torque between the drive shaft 20 and the impeller 1.

[0078] Fig. 8 shows an enlarged fragmentary side view of the impeller 1 with the drive shaft 20 mounted. This side view shows the six screws 36 and 37 which fasten the flange 29 of the wheel carrier shaft element 23 to the hub element 4. The hole pattern is arranged such that the threaded holes are located at those points on the edge 18 of the hub element 4 from which the pressure spoke elements 3 extend radially outwards.

[0079] Fig. 9 shows the wheel 1 as a partial sectional view according to the section line IX - IX, as noted in Fig. 2. The hub element 4 is cut at a point away from the pressure spoke element. The illustration shows that the hub element 4 is also hollow. A wheel axle is also shown in dashed lines as an example. The wheel axle is fixedly mounted in a bicycle frame, or rather its front wheel fork. Furthermore, two rolling bearings are also indicated by dashed lines, which comprise an inner ring and an outer ring. In this example, the rolling bearings are seated with their inner rings on the stationary wheel axle. The outer rings, however, are seated in the wheel 1, namely in the hub shell 11 of the hub element 4, so that in this example the outer rings rotate together with the wheel 1.

[0080] Fig. 10 shows a view of an alternative bicycle component. The structure of this alternative bicycle component is explained using the area of ​​a pressure spoke element 3 of a wheel, as in Fig. 4, as an example. The component comprises a hollow wheel body 5 which is manufactured in one piece and has a component wall, here a wheel wall 6 which encloses a cavity 7. The wheel wall 6 is manufactured in a closed molding tool from a thermoplastic material. The one-piece design of the wheel wall 6 is produced by means of rotational molding in an externally heated molding tool provided for rotational molding. The alternative in Fig. 10 differs from the example in Fig. 4 in that a foam 40 is additionally arranged in the hollow wheel body 5, which foam fills the cavity 7 in the present example (foam filling).

[0081] The foaming process was carried out within the cavity while the rotational molding of the wheel wall 6 was still in progress, using molten thermoplastic material for the wheel wall 6. The foam starting material was filled into the molding tool as granules via a suitable filling agent. The granules used can be expanded through a chemical reaction. For this purpose, they contain a blowing agent. In this example, the blowing agent is designed to evaporate upon application of heat. The application of heat also melts the starting material, which subsequently foams due to the evaporating blowing agent.

[0082] Fig. 11 shows a further example of an alternative bicycle component. For this alternative, too, the construction and manufacture of the alternative bicycle component is explained using a wheel as an example. The example is based on the representation of the wheel in Fig. 5. According to Fig. 11, the bicycle component is again designed as a one-piece hollow body, here the wheel hollow body 5 with a component wall, namely the wheel wall 6. The wheel wall 6 encloses a cavity 7. It is manufactured in a closed molding tool from a thermoplastic. The one-piece design of the wheel wall 6 is again produced by means of rotational molding in a molding tool that can be heated from the outside for rotational molding.

[0083] The alternative in Fig. 11 differs from the example in Fig. 5 and from the example in Fig. 10 in that a foam 41 is additionally arranged in the Lauradh hollow body 5, which in the present example coats the component wall of this bicycle component, namely a wheel wall 6, on its inner side facing the hollow space 7 (foam layer). The hollow space 7 of the wheel hollow body 5 is reduced as a result, but does not disappear in all areas. In area 41a, however, the cross-section of the hollow space 7 is so small that in some areas in the present example a layer thickness has resulted there that leaves no hollow space, and consequently a foam filling 41a has formed in this area.

[0084] List of reference symbols

[0085] balance bike

[0086] Rim element

[0087] Pressure spoke element a Stem-shaped base b Branch element c Branch element

[0088] Hub element

[0089] Impeller hollow body a RFID storage element

[0090] bike wall

[0091] cavity

[0092] Rim bed

[0093] Rim flank 0 Rim flank key Hub shell 2 Knot 3 Through hole (large) 4 Through hole (small) 5 Threaded hole 6 Threaded hole 7 Middle 18 Edge (hub element)

[0094] 19 Ring-shaped aluminum element

[0095] 20 drive shaft

[0096] 21 Shaft element

[0097] 22 Shaft element

[0098] 23 Wheel carrier shaft element

[0099] 24 Support shaft element

[0100] 25 Cylindrical wheel carrier surface

[0101] 26 warehouse sales

[0102] 27 Gear element

[0103] 28 Toothed washer

[0104] 29 Flange

[0105] 30 through hole

[0106] 31 bearing seat

[0107] 32 spline profile

[0108] 33 hub profile

[0109] 34 Passage opening

[0110] 35 Passage opening

[0111] 36 screw

[0112] 37 Screw

[0113] 40 foam filling

[0114] 41 Foam layer

[0115] 41a Foam filling

[0116] D inner diameter

[0117] L Length (hub shell)

[0118] DF nominal rim diameter

[0119] K circle diameter (nodes)

Claims

Claims: Wheel (1) for a bicycle, comprising a rim element (2), several spoke elements (3), and a hub element (4) made of a thermoplastic material, wherein the rim element (2) is formed in one piece together with the spoke elements (3) and together with the hub element (4), characterized in that a wheel hollow body (5) with a closed wheel wall (6) is formed, that at least the rim element (2) and the spoke elements (3) are hollow, and that the one-piece construction of the wheel (1) is produced by rotational forming in an externally heated rotational forming tool. Wheel according to claim 1, characterized in that the wheel hollow body (5) has areas with different wall thicknesses (t) of the wheel wall (6). Wheel (1) according to claim 2, characterized in that the areas with different wall thicknesses The areas of the wheel wall (6) with varying thickness (t) are produced by a region-specific differential heat input from the outside into the rotational molding tool. Wheel (1) according to any one of claims 1 to 3, characterized in that the thermoplastic material of the wheel wall (6) is selected from one of the following plastics: polypropylene (PP), preferably polyethylene (PE), particularly preferably high-density polyethylene (HDPE). Wheel (1) according to any one of claims 1 to 4, characterized in that the thermoplastic material is fiber-free.Wheel (1) for a bicycle, comprising a rim element (2), several spoke elements (3) and a hub element (4) made of a thermoplastic material, wherein the rim element (2) is formed in one piece together with the spoke elements (3) and together with the hub element (4), characterized in that each spoke element (3) is rooted on the hub element (4) and forms a trunk-shaped base (3a), that the trunk-shaped base (3a) of at least one spoke element (3) extends away from the hub element (4) in the direction of the rim element (2) and is divided into at least two branch elements (3b, 3c), and that at least one branch element (3b, 3c) is connected to the rim element (2). Wheel (1) according to claim 6, characterized in that the rim element (2) has a nominal rim diameter in the range of 150 mm to 650 mm. Wheel (1) according to claim 7, characterized in that the two branch elements (3b, 3c) and the stem-shaped base (3a) of the pressure spoke element (3) meet at a node (12), that the node (12) lies on a coaxial circular diameter (K) with respect to the hub element (4), and that the size of the circular diameter (K) is in the range of 0.4 to 0.6 times the nominal rim diameter (DF) of the rim element (2). Wheel (1) according to any one of claims 1 to 8, characterized in that the hub element (4) has a hollow cylindrical hub sleeve (11).A wheel (1) for a bicycle, comprising a rim element (2), several spoke elements (3), and a hub element (4) made of a thermoplastic material, wherein the rim element (2) is formed in one piece together with the spoke elements (3) and together with the hub element (4), characterized in that the hub element (4) has a hollow cylindrical hub sleeve (11) whose inner diameter (D) is at least as large as the length (L) of the hub sleeve (11) in its axial direction. A wheel (1) according to claim 10, characterized in that the dimension of the inner diameter (D) of the hub sleeve (11) is in the range of a factor of 1.0 to 2.0, based on the length (L) of the hub sleeve (11). Wheel (1) according to claim 10 or 11, characterized in that the hollow cylindrical hub sleeve (11) of the hub element (4) is prepared for this purpose. tet is, optionally either with a drive shaft (20) or to cooperate with a stationary wheel axle. Wheel (1) according to one of claims 10 to 12, characterized in that at least one means (17) is provided on the hub element (4) with which a torque can be transmitted. Wheel (1) according to claim 13, characterized in that the means (17) for transmitting the torque comprises several threaded holes (15, 16) which are arranged distributed circumferentially around the hub sleeve (11) on an edge (18) of the hub element (4). Wheel (1) according to claim 13 or 14, characterized in that the means (17) for receiving a torque is configured to attach a drive shaft (20) to the hub element (4) and / or to attach a brake disc to the hub element (4).Impeller (1) according to claim 14 or 15, characterized in that the threaded holes (15, 16) are arranged on the edge (18) of the hub element (4) in a metal element, and the metal element is integrated into the thermoplastic material of the impeller body (5). Impeller (1) according to any one of claims 1 to 16, characterized in that six compression spoke elements (3) are provided. Drive shaft (20) for an impeller (1) according to any one of the claims. Claims 1 to 17, characterized in that the drive shaft (20) is prepared For one-sided mounting on a bicycle frame, preferably a one-sided rear wheel carrier of a bicycle frame. Drive shaft (20) according to claim 18, characterized in that a gear element (27) is arranged which can interact with a drive means of a bicycle. Drive shaft (20) according to claim 19, characterized in that the gear element comprises a pinion for a bicycle chain or a toothed pulley (18) for a toothed belt or a gear for a drive shaft. Drive shaft (20) according to any one of claims 18 to 20, characterized in that the drive shaft (20) comprises two shaft elements (23, 24) which are arranged in alignment and can be connected. Drive shaft (20) according to claim 21, characterized in that one shaft element is designed as a wheel carrier shaft element (23) and the other as a support shaft element (24).Drive shaft according to claim 21 or 22, characterized in that both shaft elements comprise complementary connecting means (32, 34) which are configured at least for transmitting a rotary motion between the two shaft elements. Drive shaft (20) according to claim 22 or 23, characterized in that the gear element (27) is arranged on the wheel carrier shaft element (23). Drive shaft (20) according to one of claims 20 to 24, characterized in that the gear element (27) is integrally integrated. Bicycle component from the group: wheel and drive shaft, comprising a one-piece hollow body (5) with a component wall (6) enclosing its cavity (7), wherein the component wall (6) of the hollow body (5) is manufactured in a closed molding tool from a thermoplastic material, wherein the component wall (6) is one-piece, having been produced by rotational molding in a molding tool designed for rotational molding that can be heated from the outside, with the additional provision that a foam is arranged in the cavity (7), and that the foam extends at least partially as a foam layer (41) over the inside of the component wall (6) or completely fills the cavity (7) at least partially as a foam filling (40, 41a).

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