Abstract:
A hub for two-wheeled vehicles with a hub body and method of manufacturing, wherein the hub body is rotatably supported on the axle via at least one bearing. The hub body includes a first forged component and a second forged component, wherein the first and second forged components are connected with one another through at least one sleeve and wherein both of the forged components have a plurality of fastening flanges protruding outwardly for fastening spoke units.

Description:
BACKGROUND 
       [0001]    The present invention relates to a hub for at least partially muscle-powered vehicles and in particular two-wheeled vehicles having an axle and a hub body rotatably supported thereon. The invention in particular relates to a hub for a bicycle wherein the bicycle may optionally comprise electro-assistance. 
         [0002]    Different hubs have become known in the prior art for muscle-powered vehicles such as bicycles. Significant parameters for hubs in the field of sports and for professionals are the stressability and weight. These days hubs tend to consist of a light metal or a light metal alloy or they consist at least in part of a fibrous composite material for saving weight. To further reduce the weight of light metal hubs the hub body is extensively machined mechanically, by way of turning and milling with chip removal. In this way material is removed as desired in those places where material and thus weight can be saved so as to obtain a weight-reduced while still stable structure. 
         [0003]    These hubs operate reliably and can be low-weight. However, the advantage of the weight is achieved by extensive machining and chip-removing finishing of the hub body. This makes high-quality, lightweight hubs expensive. 
       SUMMARY 
       [0004]    It is therefore the object of the present invention to provide a hub which allows a low weight and the manufacture of which is less expensive. 
         [0005]    The present hub is provided for at least partially muscle-powered vehicles and in particular two-wheeled vehicles. It is particularly preferably employed for bicycles. These bicycles may comprise electric assistance. The hub according to the invention comprises a hub body and an axle wherein the hub body is rotatably supported on the axle via at least one bearing. The hub body comprises a first forged component and at least one second forged component, the first and the second forged components being connected through at least one sleeve. At least one forged component comprises a plurality of fastening flanges protruding outwardly for fastening spoke units. 
         [0006]    The hub according to the invention has many advantages. One particular advantage of the hub according to the invention consists in that the hub body comprises a first and a second forged component which are connected with one another wherein fastening flanges are incorporated for fastening spoke units. In this way a lower weight is realized together with high stressability. Unlike in hubs provided with a circumferential fastening flange, according to the invention higher strength material may be provided where required while material is entirely absent between the spoke fastening points. A simple, cost effective manufacturing process for manufacturing high-strength hubs is possible. The forged external surfaces require virtually no finishing. 
         [0007]    An advantage of the hub according to the invention is also, intentional changes to the fine structure, i.e. the crystal structure, attained in reshaping during forging. Another advantage is the minor loss of material due to which material expenditure is kept low. The first and the second forged components are in particular manufactured by die forging. Such chipless compression forming enables efficient, high-quality manufacture of die-forged components. In die-forging the forged piece is nearly entirely enclosed in a closed molding device, the die. In particular the cavity that the mold maker made in the die determines the shape of the finished first and second forged components. 
         [0008]    The high quality of the hub according to the invention has been surprising. While hubs have been forged in the past these hubs required a great deal of finishing work. One of the causes of this is that forging had often been done manually. Also the requirements for precision and stability and weight were not as high as they are these days. This is why for many decades no hubs fit for series production have been forged for sports bicycles or competition bicycles. Namely, manual forging allows for economic manufacture only of a much limited precision. 
         [0009]    A typical hub body may have a geometric shape that is formed by a central sleeve the ends of which are provided with a hub flange each. These hub flanges may extend over the entire circumference. By way of the hub according to the invention a hub is proposed in which the hub body consists for example of two forged components which are connected with one another. In this way it is possible to manufacture the two parts of the hub body by a forging process. 
         [0010]    To this end a blank may for example be employed that is shaped chipless in particular by die forging preferably in one operation so as to create the first forged component. The second forged component may be manufactured by a corresponding further forging operation. The two forged components may be connected with one another to manufacture the hub body. 
         [0011]    The two-part structure of the hub body structurally allows to manufacture each half by one single forging operation. Undercuts or the like are not necessary. Forging also allows economic production of “organic” shapes the manufacture of which by way of chip removal is complicated and can thus as a rule not be done economically. This allows new options in shaping and designing a hub. Aerodynamics can also be improved by way of design. The forging operation may require a number of steps. 
         [0012]    Each forged component may comprise a tubular structure. The tubular structures of the forged components allow to provide the sleeve which connects the two ends of the hub body with one another. 
         [0013]    Preferably the first and also the second forged component each comprise at least a plurality of fastening flanges for fastening spoke units. 
         [0014]    Preferably at least one forged component comprises a plurality of fastening flanges protruding outwardly for fastening an integral multiple number of spoke units. It is for example possible that for each single spoke unit exactly one correspondingly small fastening flange extends radially outwardly from the tubular structure. 
         [0015]    A spoke unit is preferably formed by at least one spoke nipple and a spoke. It is possible for both ends of the spoke to be provided with spoke nipples. It is also possible for one spoke end to comprise a thickened spoke head by means of which the spoke can be fixedly received in a corresponding receptacle. It is in particular also possible for the spoke unit to be received twist-proof where e.g. the spoke head is configured accordingly. 
         [0016]    In this case it is preferred for the fastener or one spoke flange to be provided and configured for fastening a spoke or hub nipple or else for fastening a spoke head. 
         [0017]    In this configuration the first forged component and the second forged component comprise fastening flanges for fastening spoke units. 
         [0018]    Advantageously the first forged component and also the second forged component each comprise at least one bearing seat to rotatably support on the axle the respective forged component and the entire hub body. 
         [0019]    To achieve high precision it is preferred that after the forging operation at least the bearing seats are finished by chip removal. It is also preferred for holes to be bored or grooves to be milled at the fastener to receive the spokes correspondingly. Another chip-removing finishing may be done on the inside face and in the joining area with the sleeve. 
         [0020]    Separate finishing of the fasteners for the spokes to reduce weight is not necessary. In this way a very simple and efficient manufacturing process is provided on the whole with which to manufacture cost effective, high-quality, and lightweight hub bodies. Simultaneously high stressability of the hub body is enabled. 
         [0021]    For axially fixing the bearings, each axially inwardly, the first forged component and/or the second forged component may each be provided with at least one bearing seat. 
         [0022]    At least one forged component may comprise a disk brake accommodation at which a disk brake may be attached. The disk brake accommodation is also preferably generated by the forging operation. The contact surface of the brake disc may be stripped to ensure a planar contact surface. 
         [0023]    The hub according to the invention may be configured as a front wheel hub or else as a rear wheel hub. Driven and non-driven variants are possible. 
         [0024]    Preferably the sleeve is integrally formed with the first and/or the second forged component. Particularly preferably the first and/or the second forged component is/are tubular in structure serving in particular for fastening with the sleeve or the other forged component. 
         [0025]    Preferably the sleeve comprises at least one slip-on portion. If the sleeve is provided as a separate part the sleeve may comprise at each of its ends a slip-on portion to be slipped onto an inserting portion of the first and/or the second tubular structure. 
         [0026]    It is also possible for the sleeve to comprise at least one inserting portion. If the sleeve is again provided as a separate part, the sleeve may comprise at one or both of its ends an inserting portion to be inserted into a slip-on portion of the first and/or the second tubular structure. 
         [0027]    If the sleeve is part of a forged component then the sleeve is virtually formed by a tubular structure of the first and/or the second forged component. For connecting the two forged components the other of the tubular structures is pushed into or onto the one of the tubular structures to connect the two forged components with one another. 
         [0028]    The inserting portion and the slip-on portion are dimensioned such that the inserting portion can be inserted into the slip-on portion. This allows a particularly simple connection. The dimensions of the inserting portion and the slip-on portion allow a firm, reliable seat of the sleeve and the tubular structures upon one another. To support and guarantee the correct, snug mounting the angular alignment may be done by corresponding gluing gauges. 
         [0029]    If both of the forged components are tubular in structure then preferably the tubular structure of the first forged component is shorter than the tubular structure of the second forged component. In particular is the tubular structure of the first forged component less than half the length of the tubular structure of the second forged component. This achieves high stability with a low weight. Furthermore, a new design results which due to intentional and e.g. contrasting coloring may result in entirely new options for optical designs. Moreover, advantages ensue regarding the mold and unit costs. 
         [0030]    Particularly preferably the tubular structure and the sleeve or the two tubular structures overlap in an overlapping portion. The overlapping portion comprises at least one guiding portion and at least one gluing portion. 
         [0031]    The guiding portion serves for defined assembly and guiding of the two forged components toward one another. The gluing portion is, however, preferably provided with at least one adhesive and serves to transmit the required adhesive capacity. 
         [0032]    The gluing portion is preferably configured as a snug fit and particularly preferably the gluing portion is provided with at least one radial space between the first forged component and the second forged component at least in sections over the circumference. The radial space is preferably filled at least in part with at least one adhesive substance. Particularly preferably the radial space at the gluing portion is between 0.05 mm and 1 mm and in particular between 0.10 mm and 0.50 mm. 
         [0033]    By way of combining the guiding portion with the gluing portion the overlapping portion enables a high-strength connection of the two forged components with one another or with the sleeve while by way of the guiding portion a precise, reproducible alignment of the first forged component with the second forged component is ensured. 
         [0034]    The hub body according to the invention substantially consists of a first forged component and a second forged component, the first and the second forged components being connected with one another through a sleeve. It is possible for the first and the second forged components to comprise a tubular structure arranged at least partially inside one another to be fastened to one another. 
         [0035]    The hub body according to the invention provides a very stress-tolerant hub body which has a low dead weight. Manufacturing is simple and cost effective such that higher stability can be achieved with a lower weight. 
         [0036]    Another hub body according to the invention substantially consists of one single forged component comprising fasteners for spoke units at both ends. Preferably such a hub body is substantially tubular in design. The applicant reserves the right to claim these hub bodies separately. 
         [0037]    In all the configurations the ratio of the maximum outer diameter to the minimum inner diameter is preferably between 1.25 and 2, in particular between 1.4 and 1.85. If a disk brake accommodation is provided, then the ratio is preferably between 1.7 and 2.0. Absent a disk brake accommodation, the ratio is preferably between 1.3 and 1.7. The maximum outer diameter is measured over the fasteners. On the whole, a slim, tubular hub body is provided. 
         [0038]    The method according to the invention serves to manufacture a hub with a hub body and with an axle and at least one bearing for rotatably supporting the hub body wherein for manufacturing the hub body a first forged component is formed from a first blank by way of die forging. A second forged component is formed from a second blank by way of die forging. The two forged components are connected with one another through a sleeve. In this method by way of die-forging at least one forged component is provided with a plurality of fastening flanges protruding outwardly for fastening spoke units. 
         [0039]    It is possible for the first and the second tubular structure to be at least partially pushed into one another for fastening. It is also possible for the first tubular structure and the second tubular structure to be screwed with one another. A precise angular alignment of the two parts may be ensured by precise manufacture and/or by a displaceable stopper and/or gluing the screw-thread in the snug fit. 
         [0040]    It is in particular also possible for the first forged component and the second forged component to be glued with one another for manufacturing the hub body. 
         [0041]    On the whole the invention provides an advantageous hub and an advantageous hub body which are cost effective in manufacture and which combine high stability with a low weight. Extensive chip-removing finishing for reducing weight is not necessary. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0042]    Further advantages and features of the present invention can be taken from the exemplary embodiments which will be discussed below with reference to the enclosed figures. 
           [0043]    The drawings show in: 
           [0044]      FIG. 1  a first bicycle with hubs according to the invention in a side view; 
           [0045]      FIG. 2  a mountain bike with hubs according to the invention in a side view; 
           [0046]      FIG. 3  a first perspective illustration of the forged components of a hub according to the invention; 
           [0047]      FIG. 4  another perspective illustration of the forged components of the hub according to the invention according to  FIG. 3 ; 
           [0048]      FIG. 5  a cross-section of the two forged components of the hub according to  FIG. 3 ; 
           [0049]      FIG. 6  the assembled hub body according to  FIG. 5 ; 
           [0050]      FIG. 7  an enlarged, schematic illustration of the overlapping region of the two forged components of the hub body according to  FIG. 5 ; and 
           [0051]      FIG. 8  another hub body in a sectional view. 
       
    
    
     DETAILED DESCRIPTION 
       [0052]    With reference to the enclosed figures exemplary embodiments of hubs  1  according to the invention will be discussed below. 
         [0053]    In  FIG. 1  a vehicle  100  configured as a two-wheeled vehicle  50  and in particular as a racing bicycle is illustrated in a schematic side view. The bicycle  50  is muscle-powered at least in part and may be provided with an electric auxiliary drive. 
         [0054]    The racing bicycle is illustrated in a simplistic side view and comprises a front wheel  51  and a rear wheel  52  and a frame  53 . A handlebar  56  serves as a control and may have different configurations. 
         [0055]    Beneath the saddle  57  a battery  58  may be provided which is employed in particular for electro-assisted two-wheeled vehicles. Generally speaking, such a battery  58  may be attached to the frame in other places or incorporated into the frame or attached elsewhere. 
         [0056]    In the bicycle according to  FIG. 1  the tire  60  may be configured as a tubeless tire and for example be glued onto the rim  61 . The rims  61  of the front wheel  51  and the rear wheel  52  are each connected with the hub via spoke units  10  with spokes  27 . 
         [0057]    The rear wheel  52  is provided with a hub  1  according to the invention as the rear wheel hub  3  while the front wheel is equipped with a front wheel hub  4 . 
         [0058]    In  FIG. 2  a mountain bike bicycle  50  is illustrated in a simplistic side view comprising a front wheel  51  and a rear wheel  52 , a frame  53 , a sprung front fork  54  and a rear wheel damper  54 . In this exemplary embodiment, disk brakes are provided. The rear wheel  52  is provided with a hub  1  according to the invention as the rear wheel hub  3  and the front wheel  51  is provided with a front wheel hub  4  as the hub  1 . 
         [0059]      FIG. 3  shows a perspective view of the hub body  2  of a hub of the bicycle according to  FIG. 1  or  2 . 
         [0060]    The hub body  2  consists of a first forged component  6  and a second forged component  7 . The forged component  6  presently comprises a tubular structure  8  and the forged component  7  comprises a tubular structure  9 . The tubular structures  8  and  9  comprise cylindrical or at least approximately cylindrical portions with the cylindrical portion at the tubular structure  8  showing less than half the length of the cylindrical region at the tubular structure  9 . 
         [0061]    The tubular structures  8  and  9  form a sleeve  5  via which the two forged components are connected with one another. 
         [0062]    Both the first forged component  6  and the second forged component  7  comprise fastening means for spoke units  10 . It is possible for hub nipples to be disposed at the forged components  6 ,  7 . Or else it is possible for spoke heads of spokes  27  of the spoke units  10  to be fastened to the fastener  24  or fastener  25 . 
         [0063]    The fasteners  24  and  25  are presently configured as separate fastening flanges presently extending approximately radially outwardly from the first forged component  6  or the second forged component  7 . It is also possible for the fasteners  24  and  25  to be configured as circumferential hub flanges. 
         [0064]    For fastening the two tubular structures  8  and  9  with one another the first forged component  6  comprises at the tubular structure  8  an inserting portion  18  which is inserted in a slip-on portion  19  of the tubular structure  9 . 
         [0065]    The forged component  6  comprises in the present exemplary embodiment a disk brake accommodation  16  to which a disk brake can be screwed. 
         [0066]      FIG. 4  shows another perspective view of the hub body  2  according to  FIG. 3 , presently showing the axial configuration of the fastening flanges  11  on the first and the second forged components  6 ,  7 . This configuration allows to manufacture in a simple way, beginning from a for example annular blank, the entire first forged component  6  and/or the second forged component  7  by way of a forging operation. The forging operation creates a high-strength structure so as to enable comparatively thin wall thicknesses. 
         [0067]      FIG. 5  shows a cross-section of the first forged component  6  and the second forged component  7  with the two forged components  6  and  7  disposed spaced apart from one another. This is for example the situation shortly prior to mounting. The fastening flanges  11  comprise holes for receiving the spokes which have been inserted after forging. In the interior of the forged components  6  and  7  bearing seats  12  and  13  are provided. 
         [0068]    A shoulder  14  in the first forged component  6  serves to axially fix the bearing  4  at the bearing seat  12 . 
         [0069]    The shoulder  15  in the second forged component  7  serves to axially fix the bearing  4  at the bearing seat  13 . 
         [0070]      FIG. 6  shows the assembled state with simplistic bearings  4  and axle  3  drawn in. 
         [0071]    The presently continuous axle  3  may be configured as a hollow axle or else as a solid axle. 
         [0072]    It can clearly be seen that the first forged component  6  and the second forged component  7  overlap in the overlapping region  17 . In this region the inserting portion  18  of the first forged component  6  is inserted in the slip-on portion  19  of the second forged component such that a firm connection of the first and the second forged components  6 ,  7  is present. 
         [0073]      FIG. 7  shows in an enlarged illustration the overlapping region  17  with the first forged component  6  and the second forged component  7 . The overlapping region  17  extends over a certain axial length composed of the guiding portion  20  and the gluing portion  21 . 
         [0074]    In other configurations it is also possible that two or more guiding portions and two or more gluing portions are provided. It is for example possible to provide two guiding and two gluing portions or two guiding and one gluing portion alternatingly. 
         [0075]    The guiding portion  20  is configured as a snug fit so as to align the two forged components  6  and  7  toward one another in a snug fit. 
         [0076]    In the gluing portion  21  a radial space  22  is provided between the outer diameter of the inserting portion  18  and the inner diameter of the slip-on portion  19 . This radial space  22  is presently filled by a gluing substance  23  which is applied prior to connecting the two forged components  6  and  7 . After the gluing substance  23 , which may consist of one or more adhesives, has set, a firm connection of the two forged components  6  and  7  is provided ensuring a permanently secure connection. Due to the comparatively small radial gap  22 , high gluing strength and a reliable seat are achieved. 
         [0077]      FIG. 8  shows another variant of a hub body  2  which is presently configured tripartite. The first forged component  6  and the second forged component  7  are connected with one another via a presently separate sleeve  5 . Presently both ends of the sleeve  5  comprise slip-on portions  19  while the tubular structures  8  and  9  of the forged components  6  and  7  comprise inserting portions  18 . This results in overlapping portions  17  at both ends of the sleeve  5 . 
         [0078]    The separate sleeve may consist of a light metal or else of a fibrous composite material. 
         [0079]    It is also possible for the hub body  2  to consist substantially and in particular entirely of one single forged component which comprises at both ends fasteners for spoke units. The fasteners may be configured at circumferential spoke flanges or else be configured as illustrated in the figures. 
         [0080]    By way of the invention a robust and lightweight hub is provided which is simple to manufacture and only requires little finishing work. This allows to manufacture a very high-quality hub more cost effectively than thus far while stability concurrently increases. 
         [0081]    A disk brake accommodation  16  may be incorporated into the hub. It is also possible to provide one disk brake accommodation  16  each at both of the axial ends. The diameter in the region of the fasteners for the spoke units can be kept small which provides weight advantages. Due to this and also due to the tubular structure the costs for the required mold can be kept low. 
         [0082]    In the case of two non-symmetrical forged components, there are advantages in terms of strength, costs for the required mold, and in design. 
         [0083]    It is another considerable advantage that the hub is compatible with spokes having no hub-end screw thread. The fasteners  24 ,  25  do not have to be internally threaded for fastening the spoke ends thereto. Hub nipples may—though do not have to—be employed. Basically conventional spokes with elbowed heads can be employed. 
         [0084]    By way of an overlapping portion  17  with a guiding portion  20  and a gluing portion  21 , a hub is provided that can be mounted with precision and ease.