Method and apparatus for manufacturing spokes

A method and a device are provided for manufacturing spokes from a wire material, in particular for at least partially muscle-powered two-wheeled vehicles. The spokes include a spoke shaft having at least two shaft sections. The shaft sections differ in at least one cross-section. For shaping the cross-sections, the wire material is reshaped at least in sections by means of a shaping tool. The relative position of the wire material relative to the shaping tool is varied in the axial direction during reshaping. For shaping the cross-sections in the two shaft sections the relative position of the wire material relative to the shaping tool is varied by way of different positioning movements.

BACKGROUND

The present invention relates to a method and an apparatus for manufacturing spokes of a wire material.

Stress-resistant and reliable spokes are an essential feature of high-quality wheels for bicycles. Other than spokes made of spoke wire, some spokes are manufactured of non-metallic materials such as fiber-reinforced plastics. However, metal wire spokes still show many advantages over spokes of other materials, thus offering possibilities of manufacturing light-weight and permanent, durable wheels specifically in the field of sports bicycles.

In the case of metal spokes, the decrease of the spoke wire to different diameters is a particularly significant step, since it allows considerable weight savings. The methods used and the machinery employed are particularly significant since they have a great impact on the durability and stability of the spokes. Thus, e.g. spoke wire drawing as it is described in DE 466 866 is rather disadvantageous to the material structure and thus to its stability under load. Reducing machines which reduce the diameter by hammering have been found to be particularly advantageous. This improves the toughness of the wire material and enhances the stability under load of the spoke.

The machines known in the prior art per se allow reliable manufacturing of spokes where the desired different thicknesses can be adjusted with sufficient precision. However, different wheel types and spoke insertion systems require a great variety of spoke types showing different sections of varying thickness and different lengths of transition sections between the different thickness sections. The known manufacturing machines and manufacturing methods only achieve comparatively rough tolerance ranges so that transition sections may turn out to be longer or shorter in different and in particular even in the same types of spokes. Although these tolerances actually do not affect the technical quality of the spokes they cause optical differences which are undesirable. To prevent these differences in a finished wheel, the spokes may be selected or classified prior to mounting. However, this considerably increases the operating steps and produces more rejects.

It is therefore the object of the present invention to provide an improved manufacturing of spokes, in particular yielding higher precision and narrower tolerances.

SUMMARY

This object is solved by a method for manufacturing spokes wherein each of the present spokes comprises at least one spoke shaft having at least two shaft sections. The shaft sections differ at least in a cross-section. To configure the cross-sections, the wire material is reshaped at least in sections by means of at least one shaping tool. Further advantages and features of the invention can be taken from the exemplary embodiments.

The inventive method serves to manufacture spokes from a wire material. The wire material is in particular reshaped in at least one processing section. The relative position of the wire material relative to the shaping tool is varied in the axial direction during reshaping. For shaping the cross-sections, the relative position of the wire material relative to the shaping tool is varied in the at least two shaft sections by way of different positioning movements.

The method according to the invention has many advantages. It is a considerable advantage that the relative position of the wire material is varied by applying different positioning movements. This allows considerable improvement to the dimensional consistency of the manufactured spokes. Considerably narrower tolerances can be realized. In particular, in the case of spokes having different cross-sectional shapes, a higher precision can be achieved in the transition regions, the so-called tapers. This will as a rule eliminate the need for selecting the spokes for installation in a wheel since the normal production tolerances are sufficiently small to exclude e.g. optical differences.

The spokes manufactured with the apparatus are in particular suitable for at least partially muscle-powered two-wheeled vehicles and preferably for muscle-powered bicycles. The spokes are also for bicycles assisting the muscular force by means of a motor such as pedelecs. The spokes may also be provided for electric-only bicycles. It is also possible to provide the spokes for tricycles and/or four-wheeled vehicles or else for motorcycles. The spokes are in particular suitable for (at least partially) tangential and (at least partially) radial spoke insertion.

The finished spokes may e.g. be configured as round spokes and/or flat spokes. Other shapes are conceivable as well, such as bladed spokes, saber spokes, aero spokes. To obtain non-round cross-sections in the finished spoke, one or more spoke shaft sections are reshaped and in particular embossed, preferably after reducing the diameter. The invention improves dimensional consistency. Reproducibility of the spokes is enhanced and the dimensional tolerance can be improved in particular in the transition regions between different shaft sections. The manufacturing precision of the transition regions is increased and provides for better optical appearance. This is advantageous in particular for manufacturing flat spokes or other spokes having non-round sections. Reducing the diameter of a spoke section from 2.0 mm to 1.5 mm and then embossing the spoke section enhances reproducibility of the transition regions from thin to thick and flat to round.

The spoke shafts are in particular configured as single-butted, double-butted, and/or 3D spokes. The wire material is in particular a spoke wire and preferably a spoke wire of a metal or a metal wire. In the scope of the present invention the term wire material may preferably be replaced by the term spoke wire. Suitable metal materials are used for the material, such as steel, aluminum, titanium, magnesium, and/or composite materials.

It is possible to shape the cross-section of at least a first shaft section by varying the relative position of the wire material relative to the shaping tool by way of at least one first positioning movement and to shape the cross-section of at least one second shaft section by varying the relative position of the wire material relative to the shaping tool by way of at least one second positioning movement and for the first positioning movement to differ from the second positioning movement.

It is particularly preferred to vary the relative position by means of a positioning movement ensuring an even, homogeneously reshaping course in the longitudinal direction of the wire material. The positioning movement preferably takes place by moving the wire material. The wire is for example pushed and/or in particular drawn.

In a particularly preferred specific embodiment, the positioning movements differ by their effective speed. The effective speed corresponds in particular to the duration of shaping the section having the respective cross-section relative to the length of the section having the respective cross-section. The effective speed in particular takes into account not only the speeds of the actual movements but also stops or standstill during reshaping. The positioning movements are in particular significantly different. The effective speeds differ for example by a minimum of 5% or 10% or more. A smaller or larger difference is also possible. The matching of speeds during processing respectively reshaping is particularly advantageous to the dimensional consistency and thus to the optical appearance. The speeds may be varied in steps or else continuously.

The positioning movements may differ in their maximum and/or minimum speeds. It is possible for the positioning movements to have identical effective speeds. One of the positioning movements is for example performed including at least one stop or multiple stops compensated by higher maximum speeds. It is possible to keep the speed constant. Or else it is possible for the speed to be variable, for example increasing and/or decreasing over time. These configurations are particularly advantageous since the speeds employed during reshaping have considerable impact on the precision and quality of the reshaping process.

It is preferred for at least one positioning movement to be performed at intermittent speeds. It is also possible to perform at least one positioning movement at a continuous speed. The intermittent speed comprises in particular controlled speed variations which are in particular relevant to the reshaping process. Very short-term speed variations during starting or stopping at the start or end points of a positioning movement preferably do not qualify as controlled speed variations in the sense of the present invention. For example, one shaft section may be processed at a constant speed while another shaft section is reshaped at another speed that is constant over a specified time or at a speed showing controlled increase and/or decrease over a specified time.

At least one of the positioning movements is preferably a continuous movement. These continuous positioning movements are in particular characterized by an absence of standstills or stops. The continuous movement may be performed at a consistent or variable speed. Such a continuous movement is in particular provided for a shaft section having a constant cross-section. Continuous positioning movements allow particularly fast reshaping of spoke sections.

At least one positioning movement may be an incremental movement. Incremental movements are in particular characterized by at least one standstill and/or at least one stop. It is also possible for the incremental movement to show a so-called pilger motion. Changes to the direction of movement may be provided. A movement into one direction is for example followed by partial movement in the opposite direction. This allows processing shaft sections multiple times respectively redundant processing. Incremental movements are preferably employed for shaft sections having a variable cross-section. Uniform, soft or continuous speed transitions are likewise possible.

In all the configurations, the shaping tool preferably rotates about a longitudinal axis of the wire material. The shaping tool is for example received in a rotary tool head which rotates about the longitudinal axis of the wire material during reshaping. This configuration offers the advantage to allow using shaping tools which only act on part of the wire material circumference while still ensuring even, regular reshaping over the entire circumference of the wire material. The shaping tool is in particular rotated about the longitudinal axis of the wire material on which hammering is being applied repeatedly. Particularly preferably, the rotational speed and/or the angular speed of the shaping tool is matched to the positioning movement and in particular to the speed of the positioning movement. This synchronization allows even, regular reshaping with precisely configured transitions between different cross-sections. The rotational speed may be varied while a spoke is being processed.

Preferably, at least one positioning movement is interrupted for a predetermined time interval. The time interval of the interrupted positioning movement in particular corresponds at least to the duration of a rotation of the shaping tool about the longitudinal axis of the wire material. For example, the advance of the wire material is stopped while the shaping tool is rotated once or several times about the wire material. It is also possible for the time interval of the interrupted positioning movement to correspond to at least one eighth or one fourth or one half rotation of the shaping tool. Or else the time interval may correspond to three quarters of a rotation of the shaping tool. It is also possible to interrupt the positioning movement over an extended time, for example for two or three or four or a plurality of rotations of the shaping tool. These measures enable a reproducible transition in the transition regions and/or at the spoke ends. Then the transition regions can be precisely adapted to the form of the shaping tool.

Or else it is possible for the time interval of the interrupted positioning movement to correspond at least to the duration of setting at least one characteristic magnitude for reshaping. For example, a reduction depth and/or an embossed dimension may be adjusted by displacing the shaping tool. Then, the advance is preferably stopped during adjustment. Or else, setting may be done during an ongoing positioning movement.

The shaping of shaft sections having identical cross-sections is preferably provided by way of identical positioning movements. The identical cross-sections show in particular a consistent transverse dimension, for example a maximum and/or minimum diameter. Or else it is possible for the identical cross-sections to show identical cross-sectional shapes.

Shaping cylindrical shaft sections is preferably performed by positioning movements at identical effective speeds. It is possible to provide different diameters for the cylindrical shaft sections which are reshaped at identical effective speeds. It is also possible to provide identical maximum and/or minimum speeds for the positioning movement. It is also possible to provide these settings for shaping oval shaft sections or complex respectively tapered cross-sectional shapes.

A particularly preferred specific embodiment provides for shaft sections having variable cross-sections to be shaped by way of a positioning movement at a lower effective speed than is provided for shaping shaft sections having a consistent cross-section. This configuration offers the advantage of a high processing speed for simple shaft sections while high dimensional consistency can be achieved in more complex configurations of shaft sections. Thus, manufacture on the whole achieves narrow tolerances while concurrently ensuing economic throughput. The shaft sections having variable cross-sections may for example be conical or cone-shaped.

Shaft sections having variable diameters are preferably shaped by means of positioning movements at lower effective speeds than in the immediately adjacent shaft sections if the shaft section having a variable diameter is configured as a taper between two cylindrical shaft sections each having different diameters. In these tapers the decrease of the speed of the positioning movement is particularly effective on dimensional consistency.

Particularly preferably the shaft section serving as a taper is configured cone-shaped. Or else it is possible for the shaft section serving as a taper to be configured conical. The taper may be curved wherein the curve is characterized by at least one function. The taper may be characterized by at least one variation of the cross-sectional shape. These tapers are present for example in a transition from a shaft section configured as a flat spoke to a cylindrical shaft section.

Particularly preferably, the effective speed and/or the maximum speed of the positioning movement is reduced prior to reaching the taper. The effective speed and/or the maximum speed is preferably increased after the taper. The effective speed and/or the maximum speed of the positioning movement remains in particular even during the taper. It is possible to reduce the speed of the positioning movement already prior to reaching the taper. It is also possible to reduce the speed of the positioning movement only in the region of the taper. The speed of the positioning movement is preferably increased again only after shaping the taper. It is also possible to increase the speed of the positioning movement already while shaping the taper.

It is possible to provide for incremental positioning movements while shaping a taper. Standstills of the positioning movement may for example be provided. Standstills of the positioning movement are for example used for adapting a characteristic dimension of reshaping. The reduction depth is for example set during a standstill. To this end, the shaping tool may be at least partially displaced.

It is particularly preferred to provide the positioning movement in dependence on a rotational speed of the shaping tool about the longitudinal axis of the wire material. It is also possible to provide the positioning movement in dependence on the applied hammering rate of the shaping tool on the wire material. The effective speed and/or the maximum speed and/or the minimum speed of the positioning movement are in particular set in dependence on the rotational speed and/or the hammering rate of the shaping tool. Adjusting the positioning movement and in particular setting the effective and/or maximum speed of the positioning movement is in particular synchronised with the rotational speed and the hammering rate of the shaping tool respectively. Such synchronisation allows to ensure modifications in respect of the positioning movement in optimal coordination with a possible or actual speed of the reshaping process.

It is possible to set the effective speed and/or the maximum speed of the positioning movement in dependence on the diameter of the cross-section of the shaft section. It is possible to choose the effective speed and/or the maximum speed of the positioning movement to be higher inversely proportional to the intended reduction of the wire material. It is for example possible to set the reduction depth by way of choosing the effective and/or maximum speed of the positioning movement. For example, if less reduction of the wire material is provided, a higher speed for the positioning movement is chosen.

It is furthermore preferred in all the configurations to reshape the cross-sections of the wire material at least in sections by way of hammering applied by the shaping tool. The wire material is particularly preferably reduced by hammering by means of the shaping tool. It is also possible for the shaping tool to act on the wire material by bucking and/or embossing. For shaping the cross-sections, the shaping tool or another, separate shaping tool may act on the wire material in different ways of reshaping, in particular by way of compression forming. These configurations offer the advantage of considerably improving the toughness of the spokes. These reshaping processes thus offer considerable advantages for example over reshaping by drawing techniques.

To adjust the diameter of a cross-section, the reduction depth of the shaping tool is adjusted by at least one adjustment device. It is also possible to adjust at least one other reduction dimension by means of the adjustment device. The duration of setting the shaping tool is in particular taken into account when choosing the speed of the positioning movement. It is also possible to stop the positioning movement while the adjustment device is adjusting the shaping tool. The speed of the positioning movement is in particular reduced during adjustment by the adjustment device.

The shaping tool preferably consists of at least two opposed tool units. The tool units are in particular employed in synchrony.

The tool units are preferably operated in synchrony. Particularly preferably, the tool units act on the wire material by hammering in synchrony. It is also preferred to rotate the tool units about the longitudinal axis of the wire material while applying hammering. The tool units are in particular arranged opposed. It is also possible for one of the two tool units to apply hammering on the wire material while the other of the tool units serves as an abutment. Particularly preferably the shaping tool comprises four tool units opposed to one another in pairs. The pairs of the tool units are employed alternatingly, successively, in synchrony. Preferably the two tool units of a pair are operated in synchrony.

In all the configurations, it is furthermore particularly preferred to perform the positioning movement by advancing the wire material. The positioning movement for example comprises drawing and/or pushing the wire material. At least one feeding device may be provided therefor. The feeding device is for example configured as an advancing device. It is also possible to perform the positioning movement by displacing the shaping tool. It is also possible to displace both the wire material and the shaping tool.

The inventive device serves to manufacture spokes from a wire material. The spokes are in particular provided for at least partially muscle-powered two-wheeled vehicles. The spokes each comprise at least one spoke shaft having at least two shaft sections. The shaft sections differ by at least one cross-section. The device comprises at least one reshaping device. The reshaping device is suitable and configured to configure the cross-sections by reshaping the wire material at least in sections by means of at least one shaping tool.

The reshaping device is suitable and configured to vary the relative position of the wire material relative to the shaping tool in the axial direction during reshaping by means of at least one feeding device. The feeding device is suitable and configured to vary the relative position of the wire material relative to the shaping tool for shaping the cross-sections of the at least two shaft sections by way of different positioning movements.

The device according to the invention shows the advantage to allow manufacturing spokes showing particular dimensional consistency and precision. Moreover, the device enables particularly high throughput in manufacturing. The device can be operated in particular according to the methods described above. The device comprises in particular at least one control device. The control device is in particular suitable and configured to synchronize the positioning movement by way of a rotary motion of the shaping tool about a longitudinal axis of the wire material. The control device is preferably also suitable and configured to operate the positioning movement in synchrony with an adjustment device for adjusting a reduction dimension.

In all the configurations of the device and the method according to the invention, the advance rate or the relative speed of the relative motion between the wire material and the reshaping device is preferably controlled and preferably varied while a spoke is being processed. The relative speed may temporarily be very low, zero or even negative, e.g. to enable particularly intensive processing of one or more sections.

In all the configurations, reshaping and in particular forging the spoke wire consisting of a wire material preferably occurs incrementally. The shape of the spoke is in particular achieved by a plurality of blows. After reshaping by hammering the spoke shows as a rule a round outer contour over the spoke length. Thereafter at least one further reshaping process e.g. by embossing may be provided to form the spoke over at least a longitudinal section of the substantially round spoke to a desired different cross-sectional shape, e.g. a bladed shape. There the spoke is configured as a flat spoke and/or is flattened knife-like.

In specific embodiments of all the configurations, it is preferred for the reshaping device to be configured as, or to comprise, a reducing head. The reducing head comprises (at least) one outer head and (at least) one inner head which are rotatable relative to one another. In particular, the inner head is configured rotatable. The speed of rotation of the inner head is preferably between approximately 500 and 2000 revolutions per minute (rpm).

Particularly preferably the rotational speed of the inner head is between approximately 750 and 1500 rpm. A preferred rotational speed is ca. 925 rpm. In a specific configuration the rotational speed of the inner head may be varied between approximately 800 and 1400 rpm.

Particularly preferably, the reshaping device comprises four tool units and one actuating device configured as a hammering roller device comprising a plurality of hammering roller units that are substantially fixed or stationary in the peripheral direction and displaceable (in particular rotating around the spoke wire) hammering roller units. The number of the rotary hammering roller units preferably correlates with the number of the tool units and/or the number of the stationary hammering roller units. The number of the rotary hammering roller units is particularly preferably larger than the number of the stationary hammering roller units. Preferably the number of the rotary hammering roller units is an even number. The number of the displaceable hammering roller units is preferably not an integer multiple of the number of the stationary hammering roller units. The number of the displaceable hammering roller units particularly preferably differs by 2 from an integer multiple of the number of the stationary hammering roller units.

Preferably, the number of the stationary hammering roller units is 4 and the number of the rotary hammering roller units is larger than or equal to 6. Particularly preferably, the number of the rotary hammering roller units is 14. Given four tool units engaged in pairs with the spoke wire and 14 hammering roller units displaceable in the peripheral direction and four hammering roller units fixed in the peripheral direction, a speed of e.g. 900 rpm results in a number of 210 blows per second on the spoke wire so as to allow an effective and high-quality manufacture of spokes.

The (axial) advance rate respectively relative speed between the spoke and the reshaping device is in particular between 0.005 and 0.04 m/s and particularly preferably between 0.0075 and 0.025 m/s.

Given a spoke length of 300 mm, the resulting processing times are between 5 and 40 seconds depending on the initial diameter and reduced diameter.

Reducing the diameter serves not only to reduce weight but in particular also to improve the mechanical properties, similar to the principle of a uniform strength bolt in which a reduction relieves stresses at the head and the screw shaft by means of the “elastic” center part. Presently the diameter-reduced section acts as the “elastic” center part.

DETAILED DESCRIPTION

FIG. 1shows a schematic illustration of a two-wheeled vehicle200configured as a bicycle. The bicycle comprises two wheels201, a front wheel and a rear wheel. Furthermore, a frame203, a fork204, a handlebar206, and a saddle207are provided. The drive is provided by pedals and in this case, a derailleur. The front wheel and the rear wheel are each attached to dropouts at the fork204respectively the frame203. The front wheel and the rear wheel101,102each comprise a rim210and spokes100manufactured by means of the device according to the invention and connected with a hub208. Due to the image scale the spokes1are shown schematically only and will be illustrated in more detail with reference toFIG. 2.

FIG. 2illustrates a schematic longitudinal view of a spoke100manufactured by way of the method according to the invention. The figure is not true to scale to better illustrate the principle. Two exemplary cross-sections103of the spoke are illustrated hatched. The cross-sections103differ in their diameters33. The transitions between the regions of different diameters33are provided by the tapers104. The tapers104differ in their lengths and in their gradients. An arrow indicates the longitudinal axis23of the spoke.

The spoke100has been manufactured by reshaping wire material3. The wire material used is a special spoke wire which has a tensile strength of e.g. 1200 N/mm2and more. The spoke wire was reduced by hammering on the respective cross-sections103respectively33.

The spoke100has a spoke head105at one of its ends and at the other of its ends, an external thread106which serves to screw it to a spoke nipple, which is not shown. The spoke shaft101extends between the two ends. The first end105is for attachment to the hub208. The spoke200extends outwardly from the hub208to the second end106where the external thread is then attached to the rim210by means of a spoke nipple.

This spoke100is exemplarily configured as a double-butted spoke. Other spoke shapes are also conceivable such as single-butted spokes or else flat spokes. This spoke shaft101has undergone controlled reshaping in various shaft sections111,121,131,141,151. The two shaft sections111,151at the ends105,106are configured cylindrical, having a cross-section103with a diameter of 2.0 mm. The shaft section131lying between is likewise cylindrical and has a cross-section103with a diameter33of 1.5 mm.

Such reduction of the spoke shaft101allows to noticeably reduce the weight while concurrently maintaining and even increasing the required stability. The tapers104are shaped so as to counteract an unfavorable notch effect and to allow a particularly stable transition. The shaft section121closer to the head105has a shorter taper104than does the shaft section141lying closer to the other end106. This configuration takes account of the forces occurring in the wheel201which act on the spoke100.

FIG. 3exemplarily shows the device1according to the invention for manufacturing spokes100. The device1may be operated according to the method according to the invention. The device1comprises a reshaping device2for reshaping wire material3. The wire material3is fed through the reshaping device2by means of a feeding device8which is presently configured as an advancing device.

The reshaping device2comprises a shaping tool4having two or four pairs of opposed tool units14, of which only one tool unit14is shown for better clarity. An actuating device is provided for actuating the shaping tool4. The actuating device5is configured as a hammering roller device15which comprises a plurality of stationary hammering roller units25and displaceable hammering roller units35.

An adjustment device6is provided for setting a reduction rate. The adjustment device6comprises a wedge device16disposed between the hammering roller unit35and the tool unit14. Axial displacement of the wedge device16adjusts the distance between the hammering roller unit35and the tool unit14to allow adapting the reduction depth accordingly.

FIG. 4shows an exemplary process pattern of the method according to the invention. The relative position43of the wire material3was plotted in relation to the shaping tool4versus the time702. This results in a characteristic path including each of the different positioning movements7during reshaping of the wire material73. The different positioning movements7comprise a first positioning movement712, followed by a second positioning movement722and a third positioning movement732. The drawn path reflects the maximum speeds27of the positioning movements7. Each of the positioning movements7is performed as a continuous movement37.

The respective relative positions43correspond to specific positions of the shaping tool4during the processing along the spoke shaft101. The presently shown path exemplarily shows reshaping of a spoke shaft101having a total of three different shaft sections111,121,131. The wire material3is first taken to a relative position43where reshaping of the first shaft section111begins. This shaft section is for example cylindrical and is processed by way of a suitable, rapid speed27. The same applies to the third shaft section131.

The second shaft section121is exemplarily configured as a taper104between the first shaft section111and the third shaft section131. Since the taper104exemplarily undergoes conical or cone-shaped reshaping, the speed27is accordingly reduced for the time702of processing. This allows particular precise shaping of the taper104showing very narrow tolerances.

FIG. 5shows another outline of an exemplary path of positioning movements7. Similarly, to the description inFIG. 4, a spoke100having a spoke shaft101consisting of a total of three shaft sections111,121,131, is reshaped. The first positioning movement712is performed at a lower speed27than is the third positioning movement732.

This controlling of the wire feed is useful for example in manufacturing a double-butted spoke whose shaft sections111,131show different cross-sections respectively different diameters33at their two ends105,106. For example, if the diameter33of the spoke shaft101is smaller, the processing speed27may be lower since the wire material3is reduced more in this position. Or else it is possible to provide positioning at the same or similar speeds27even given different degrees of reduction of the spoke shaft101.

For shaping the second shaft section121the presently shown process flow comprises a positioning movement722that is configured as an incremental movement47. Such incremental movement47provides for temporarily stopping the positioning movement7and temporarily bringing it up to a specific maximum speed27. The stop of the positioning movement7lasts for a specific time interval57. This time interval57corresponds for example to the duration of one rotation or part of one rotation of the shaping tool4about the wire material3. Or else it is possible to match the time interval57to the duration of adjusting the shaping tool4. The maximum speed27between stops can be chosen accordingly higher. Thus there results an overall effective speed17allowing correspondingly fast reshaping and thus an economic manufacturing throughput. Varying the speed may be done continuously over a spoke section or part of a spoke section.

It is in particular possible to choose a positioning movement7respectively speed of the relative motion between the spoke shaft and the reshaping device e.g. in the spoke sections121and141inFIG. 2that differs from that in the spoke sections111or131. In spoke sections where the thickness varies, a lower speed can in particular be chosen. Then, care is taken for the spoke shape in the respective spoke sections121and141to precisely adapt to the shape of the tool so that narrow tolerances can be achieved since the shape of the spoke section corresponds to the shape of the tool.

The spoke sections111and151having maximum diameters may be provided for no processing at all.

The presently shown method allows manufacturing spokes100having particularly narrow tolerances in particular in the region of the tapers104. A tolerance of less than +/−0.5 mm can be realized for example in the region of the tapers104. The tolerance of the methods known thus far is e.g. up to 3 mm and more. The method according to the invention thus achieves a considerable increase of dimensional consistency. Moreover, these precise transitions also offer an improved optical appearance and improved aerodynamic properties.

The increased dimensional consistency achieved with the method according to the invention is an advantage in particular for flat spokes respectively bladed spokes. Flat spokes having a wide tolerance range tend to comprise cylindrical regions or too large transverse dimensions so that problems may arise when inserting spokes through the rim hole. On the whole the method according to the invention offers considerable advantages in manufacturing spokes which can be employed in particular in building high-end wheels.