SPROCKET FOR A BICYCLE DRIVE

Description

[0001] The present invention relates to a pinion for a bicycle drive, more specifically to a pinion comprising an outer ring with external teeth for engagement with a bicycle chain, an inner ring arranged coaxially with the outer ring and connected thereto in a rotationally fixed manner, having a central opening, and a circumferential collar formed integrally with the inner ring and projecting axially to one side thereof, which is designed as a continuous collar. An inner profile with a plurality of radial projections projecting radially inward is provided on the radial inner side of the collar. Document EP3401203 discloses a pinion of this type.

[0002] The term pinion here refers to both a pinion in the narrower sense, i.e. a rear pinion, which is designed to transmit torque to a driver on a rear wheel hub of a bicycle, but also a front pinion or chainring, which is designed to absorb torque from a pedal crank of the bicycle and to transmit it via the bicycle chain and a rear pinion meshing with it to the driver and thus to the rear wheel of the bicycle.

[0003] The inner profile of such a pinion must meet various requirements. For example, the minimum radial dimension or area of ​​the projections of the inner profile is determined, among other things, by the materials of the pinion and the component to which it is coupled for torque transmission when assembled, as well as by the existing requirements regarding the torque to be transmitted and the load duration.

[0004] If the radial dimension of the projections or in other words the depth of the inner profile is too small, an undesirable deformation of a load flank of the pinion and / or the aforementioned component coupled to the pinion may occur during operation

[0005] The collar must also provide sufficient support surface in the axial direction for the components of the bicycle that are adjacent to it, so that there is no deformation during riding or excessive influence on the tightening torque when fitting the pinion or pinion cassette.

[0006] In practice, the aforementioned pinions have so far been manufactured by first producing a collar with a circular radial inner surface and a circular radial outer surface in a forming process also known as "collar drawing." The inner profile is then cut into the radial inside of the collar, while the radial outer surface of the collar remains circular.

[0007] In order for the aforementioned surfaces of the collar for axial support and in particular the surfaces for torque transmission on the inner profile to be sufficiently large, a relatively large amount of material removal and thus a high material input to produce a pinion is necessary for the known pinions.

[0008] Against the background of this prior art, the object of the present invention according to a first aspect is to provide a pinion that can be produced in a material-saving manner and has good torque transmission properties.

[0009] This object is achieved according to the invention in that an outer profile with a plurality of radial recesses is also provided on the radial outer side of the collar, which correspond to the radial projections of the inner profile in terms of number and arrangement.

[0010] This makes it possible to produce at least a preform of the final inner profile together with the outer profile in a forming process in which material is only redistributed but not removed.

[0011] Although material may be subsequently removed from the inner profile in order to create a desired profile shape and / or profile depth, compared to a generic pinion, in which the inner profile is created exclusively by material removal, the amount of material to be subsequently removed can be reduced, which reduces the necessary material expenditure.

[0012] Terms such as radial, axial, coaxial, etc. refer to a central axis of the pinion, which also corresponds to its axis of rotation during operation.

[0013] Preferably, the inner ring and outer ring of the pinion according to the invention are formed integrally with one another.

[0014] The thickness of the inner ring, i.e., its dimension in the axial direction, can be, for example, between 1.5 mm and 2 mm, preferably between 1.6 mm and 1.8 mm. The collar can protrude axially from the inner ring by a few millimeters, so that the pinion has an axial dimension of, for example, 2.5 mm to 8 mm at the central opening, preferably 3 to 7 mm, particularly preferably 3.3 mm to 6.5 mm. The aforementioned axial dimension corresponds approximately to the axial extent of the inner profile, less minimal corrections due to rounded edges.

[0015] The pinion according to the invention is preferably used as a rear pinion. In this case, the projections of the inner profile of the circumferential collar serve as driver elements designed to transmit torque from the pinion to a driver on a rear wheel hub of a bicycle.

[0016] Alternatively, the pinion according to the invention can be used as a front pinion or chainring. In this case, the projections of the inner profile of the circumferential collar serve to transmit torque from the pedal cranks or a component connected thereto to the projections.

[0017] In both cases, the circumferential collar can protrude axially inward from the inner ring when the pinion is mounted on the bicycle, i.e., toward the side closest to the center plane of the bicycle wheel. However, it should not be ruled out that in both of the aforementioned cases, the pinion could be mounted so that the circumferential collar protrudes axially outward from the inner ring, for example, if the collar is used as a spacer to an adjacent pinion.

[0018] According to the invention, it is provided that each of the projections of the inner profile has a first flank arranged in advance with respect to a predetermined direction of rotation about a central axis of the pinion and a second flank arranged trailing with respect to the predetermined direction of rotation, wherein for at least one, preferably for several and particularly preferably for each of the projections of the inner profile, the first and the second flank are not mirror-symmetrical to one another.

[0019] In configurations where torque is only transmitted in one direction of rotation, such as in a freewheel, a sufficiently large torque-transmitting surface of the first flank serving as the load flank can be achieved at the same time and, in addition, the risk of jamming can be reduced by a correspondingly smaller surface of the second flank or counter flank.

[0020] For this purpose, it can be provided, in particular, that the first flank of the at least one projection of the inner profile is radially longer than the second flank. This preferably applies to several, particularly preferably to each, projection of the inner profile. For example, a radial length of the second flank can be 75% or less of the radial length of the first flank, preferably 66% or less.

[0021] If the pinion according to the invention is used as a rear pinion, the predetermined direction of rotation is preferably the forward direction of rotation; if the pinion is used as a chainring, the predetermined direction is preferably the reverse direction of rotation, because in each of the two cases the first flank is the load flank via which torque is transmitted.

[0022] In order to be able to position the external toothing of the pinion close to the rear wheel in a space-saving and aerodynamically favorable manner in the axial direction, it can be provided that a center plane of the external toothing for engagement with a bicycle chain or a center plane of the outer ring is axially spaced from a center plane of the inner ring. Particularly preferably, an axial end face of the circumferential collar is arranged axially between the center plane of the inner ring and the center plane of the external toothing or the center plane of the outer ring.

[0023] The pinion according to the invention can be used, for example, as the final pinion of a pinion cassette, i.e. as the pinion of a pinion set which is the only one designed to directly transmit torque to a driver on a rear wheel hub of a bicycle.

[0024] Alternatively, it can also be designed as a single pinion or a plug-in pinion. In the latter case, several or all pinions of a pinion set can be designed as pinions according to the invention, each of which engages with a driver for torque transmission. The collars of the pinions according to the invention, which protrude axially to one side, can also serve as spacers, thus reducing the number of required components.

[0025] Therefore, protection is also sought for a pinion cassette for a bicycle drive, comprising a pinion set with a plurality of coaxially arranged, axially spaced apart and rotationally fixedly connected pinions with different diameters, wherein one of these pinions is a final pinion which is designed to directly transmit torque to a driver on a rear wheel hub of a bicycle, and wherein the final pinion is a pinion according to the invention as described above.

[0026] Furthermore, protection is also sought for a bicycle drive with a driver and at least one pinion according to the invention, preferably with several pinions according to the invention, or with a pinion cassette as described above.

[0027] According to a second aspect of the invention, it also relates to a method for producing a pinion for a bicycle drive, comprising the following steps: i) punching out a pinion blank with a central pilot hole and ii) further processing the pinion blank into a pinion with a central opening, an inner ring and a circumferential collar formed integrally with the inner ring and projecting axially to one side thereof, preferably into a pinion according to the invention as described above, wherein step ii) comprises the following step: a) forming the pinion blank, wherein a punch is pressed through the pilot hole of the pinion blank into a die to form the circumferential collar

[0028] The object of the invention mentioned in the introduction is achieved according to the second aspect of the invention by a method having the features of the independent method claim.

[0029] According to the invention, by forming the pinion blank in step a), both an inner profile with a plurality of radial projections projecting radially inwards is formed on the radial inside of the collar and an outer profile with a plurality of radial recesses is formed on the radial outside of the collar, which correspond to the projections of the inner profile in terms of number and arrangement.

[0030] The above explanations of the device claims contain method aspects and vice versa, so that reference is made to these above statements in addition.

[0031] Preferably, in step i), the central pilot hole is not circular but is formed such that it has a plurality of radially inwardly projecting projections which correspond in number and arrangement to the radially inwardly projecting radial projections of the later formed inner profile of the collar, which enables a simple and more uniform material redistribution in the following forming step.

[0032] The outer profile of the collar and the inner profile or at least a preliminary stage of the inner profile of the collar are then produced during the forming process, for example by means of suitably shaped punches and dies.

[0033] According to a preferred embodiment, it can be provided that step ii) after step a) further comprises a step b) in which the inner profile of the circumferential collar produced during the forming process is reworked, for example by cutting or milling.

[0034] For example, surfaces that are particularly sensitive to tolerances can be reworked, especially those that are in direct contact with the driver when assembled.

[0035] In particular, in this post-processing step b), the asymmetry of the two flanks of at least one projection, as already described with regard to the pinion, can be produced.

[0036] Thus, it can be provided that in step b) for at least one of the projections of the inner profile, preferably for several of the projections and particularly preferably for each of the projections, a first flank of the projection arranged leading with respect to a selected direction of rotation and / or a second flank of the projection arranged trailing with respect to the selected direction of rotation is or are reworked in such a way that the first flank is radially longer than the second flank after the rework.

[0037] The forming process for forming the collar can be carried out in several stages. For example, step a) after a first forming step a1), in which the collar is formed with an inner and outer profile, can preferably comprise a further forming step a2), in which the pinion blank or the pinion is further formed in order to set a predetermined axial dimension of the collar.

[0038] For this purpose, the die used in the first forming step can be replaced with a modified die. This preferably also allows the desired flatness of the collar's axial end face to be achieved. If desired, the punch used in the first forming step can also be replaced in step a2).

[0039] It should be noted in passing that the technique described above is also suitable for producing a disc brake rotor for a bicycle.

[0040] The present invention will be explained in more detail below using a preferred embodiment, which is illustrated in the accompanying figures. Fig. 1 is a schematic side view of a bicycle with a pinion according to a preferred embodiment of the present invention. Fig. 2 is the pinion according to the preferred embodiment of the invention Figure 1 in a plan view of the back of the pinion, Fig. 2a an enlarged detail of the subject of Fig. 2 Fig. 3the subject of Fig. 2 in a plan view of the front of the pinion, Fig. 4 a perspective view of the subject of Fig. 2 , Fig.5 a sectional view of the subject matter of Fig. 3 with respect to a section plane designated VV there, Fig. 6 an enlargement of the Fig. 5 area marked A, Fig. 7 an enlarged detail of a perspective view of the subject of Figures 2 to 6in a partial section, Fig. 8 a further enlarged detail of the subject of Fig. 2 , which shows the shape of the flanks of the projections of the inner profile, Fig. 9 a perspective view of a pinion cassette according to a preferred embodiment of the invention in a partial section, in which the Figures 2 to 8 shown pinion is used as a final pinion, Fig. 10 a flow chart to illustrate a method according to a preferred embodiment of the present invention, Fig. 11 a schematic representation of a pinion blank which is used in the method according to Fig. 10 as an intermediate product. Fig. 12 in partial figure a) a cross-sectional view of a in a forming step of the method according to Fig. 10used forming tool and the pinion formed therein and in partial figure b) an enlarged detail of the area marked Z in partial figure a), as well as Fig. 13 in partial figure a) a cross-sectional view of a in a further forming step of the method according to Fig. 10 used forming tool and the pinion formed therein and in partial figure b) an enlarged detail of the area marked Z in partial figure a).

[0041] For reasons of clarity, not every feature in the figures is always provided with a reference symbol; instead, only those features necessary to explain the respective figure are indicated. This applies in particular when several similar features are shown, of which, in most cases, only one or a few selected ones are provided with reference symbols.

[0042] In Figure 1A bicycle is generally designated by 10. The bicycle 10 comprises a frame 12, a front wheel 14, a rear wheel 16, a handlebar 18, and a saddle 20. Even though the bicycle 10 illustrated here as an example is a racing bicycle, it is clear that the invention described here can also be used with other types of bicycles, such as a mountain bike.

[0043] In the usual manner, a torque can be introduced into a front pinion or chainring 27 of a chainring set 26 on the bicycle 10 via pedals 22 and cranks 24. This torque is then transmitted via a closed-circuit bicycle chain 30 to a pinion cassette 32 on a rear wheel hub 17 of the bicycle 10.

[0044] The pinion cassette 32 comprises a pinion set with a plurality of coaxially arranged, axially spaced and non-rotatably connected rear pinions with different diameters, of which in the example shown the largest is a pinion 34 according to an embodiment of the invention.

[0045] The pinion 34 according to the invention serves in this case as a final pinion 36 and is designed to transfer the torque introduced via the bicycle chain 30 directly to a Figure 1 invisible driver on the rear wheel hub 17, which is more precisely related to Figure 9 is explained.

[0046] The rear pinion of the pinion cassette 32 meshing with the bicycle chain 30 can be selected in a known manner by a rear derailleur 37, and the corresponding front pinion or chainring 27 by a front derailleur 28. The rear derailleur 37 and the front derailleur 28 can each be controlled mechanically and / or electrically in a known manner.

[0047] Figure 2 shows a plan view of a rear side of the pinion 34 according to the invention, i.e. the side facing the rear wheel 16 in the assembled state. A plan view of the front side of the pinion 34 is shown in Figure 3 shown, a perspective view in Figure 4 .

[0048] The pinion 34 comprises an outer ring 40 with external teeth 42 for engagement with the bicycle chain 30 and an inner ring 44 with a central opening 46, which is arranged coaxially with the outer ring 40 with respect to the central axis M of the pinion 34 and is connected thereto in a rotationally fixed manner, and in this case is formed integrally therewith.

[0049] The inner ring 44 and the outer ring 40 are designed in a first approximation as planar annular discs and are connected to one another in a known manner by a plurality of connecting arms 43 extending obliquely outwards from the inner ring 44.

[0050] Formed in one piece with the inner ring 44 and projecting axially to one side of the inner ring 44, in Figure 2 A circumferential collar 48 is provided on the pinion 34, projecting axially towards the viewer.

[0051] The collar 48 has an inner profile 47 with a plurality of radially inwardly projecting projections 50 on its radial inner side. An outer profile 49 with a plurality of radial recesses 52 is provided on the radial outer side of the collar 48, which correspond in number and arrangement to the radial projections 50 of the inner profile 47.

[0052] In the Figures 4 to 6 It can be seen that, in this case, a center plane E 42 of the external toothing 42 or a center plane E 40 of the outer ring 40 is parallel but axially offset from a center plane E 44 of the inner ring 44. In other words, the pinion 34 is dished, which makes it possible to position the external toothing 42 closer to the rear wheel 16.

[0053] More precisely, in the example shown, an axial end face 48s of the circumferential collar 48 is arranged axially between the center plane E 44 of the inner ring 44 and the center plane E 42 of the external toothing 42 or the center plane E 40 of the outer ring 40 (cf. Fig. 6 ).

[0054] The shape of the collar 48, in particular the shape of the inner profile 47 and the outer profile 49, is described below with reference to the Figures 2a , 4 , 7 and 8 described in more detail.

[0055] In the present case, for example, the inner profile 47 has nine projections 50 evenly distributed over the circumference of the collar 48, and the outer profile 49 has nine similarly distributed recesses 52. The exact shape of the inner profile 47 can differ from the shape of the outer profile 49 and is adapted to the shape of the driver used.

[0056] Preferably, the outer profile 49 extends approximately over the entire axial length a 48 of the collar 48 and the inner profile 47 extends approximately over an axial length l, which results from the sum of the axial length a 48 of the collar 48 and the axial extension or thickness d 44 of the inner ring 44 (cf. Fig. 7 ).

[0057] The thickness d 44 of the inner ring is, for example, between 1.5 mm and 2 mm, preferably between 1.6 mm and 1.8 mm. The aforementioned axial length l is approximately 2.5 mm to 8 mm, preferably 3 mm to 7 mm, particularly preferably 3.3 mm to 6.5 mm.

[0058] The Figures 2a , 7 and 8show the shape of the inner profile 47 and the outer profile 49 of the collar 48 in various detail enlargements, which show that there is a clear asymmetry for the projections 50 of the inner profile 47, while the corresponding recesses 52 of the outer profile 49 are each constructed essentially mirror-symmetrically with respect to a respective mirror plane S, which in Figure 2a for a selected projection 50 or the corresponding recess 52 is indicated.

[0059] Each projection 50 has a first flank 50.1 (load flank) arranged leading with respect to a selected direction of rotation D (in this case the forward direction of rotation) and a second flank 50.2 (counter flank) arranged trailing with respect to this direction of rotation D, which are connected to one another by a plateau section 54.

[0060] Between directly adjacent projections 50 of the inner profile 47, a recessed region 56 is provided, which has two sections 56.1 and 56.2, wherein the first section 56.1 directly adjoins the first flank 50.1 of a projection 50, and the second section 56.2 directly adjoins the second flank 50.2 of another adjacent projection 50. The first section 56.1 is set back more than the second section 56.2, which results in the first flank 50.1 being longer in the radial direction than the second flank 50.2. For example, the radial length r 50.2 of the second flank can be 75% or less of the radial length r 50.1 of the first flank, preferably 66% or less (cf. Fig. 8 ).

[0061] As described in more detail below, the collar 48 is produced in a forming process in which the outer profile 49 and, together with it, at least one preform of the inner profile 47 are formed by using suitable tools, which Figure 8 is indicated by a dashed line and is also referred to as the preliminary inner profile 51.

[0062] The final shape of the inner profile 47, in particular the final shape of the flanks 50.1, 50.2 of the projections 50 of the inner profile 47 and the recessed areas 56 is preferably produced in a post-processing step, for example by cutting or milling.

[0063] It should be noted that in the illustrated embodiment, the radial projections of the preform 51 of the inner profile are, to a first approximation, mirror-symmetrical before the post-processing and the asymmetry of the projections 50 of the final inner profile 47 is only introduced by the post-processing step.

[0064] Before post-processing, the collar 48 has a substantially constant radial dimension r 48 of 1 to 2 mm, preferably 1.3 to 1.5 mm, particularly preferably approximately 1.4 mm, across the circumference of the collar. The radial depth r 52 of the recesses 52, which corresponds to the radial length of the projections of the preform 51 of the inner profile, is, for example, between 0.5 mm and 0.7 mm.

[0065] Fig. 9shows a perspective view of a pinion cassette 32 according to a preferred embodiment of the invention in a partial section. The pinion cassette 32 comprises a pinion set 31 with several pinions arranged coaxially with respect to the central axis M, axially spaced from one another and connected to one another in a rotationally fixed manner, the largest of which is a pinion 34 according to the Figures 1 to 8 The remaining conventional pinions are marked with the reference numeral 33.

[0066] The pinion set 31 is mounted on a driver 60 which is fixed in a known manner to the Figure 9 rear wheel hub of the bicycle 10 (not shown).

[0067] The driver 60 has a hollow cylindrical basic shape, with an annular projection 62 at one axial end, an external toothed section 64 axially adjoining the annular projection 62 and a threaded section 66 axially following this.

[0068] In order to transmit torque from the pinion set 31 to the driver 60, the driver 60 is in engagement in the region of the external toothing section 64 with the projections 50, designed as driver elements, of the inner profile 47 of the collar 48 of the largest pinion 34, designed as the final pinion 36, according to the exemplary embodiment of the invention.

[0069] An adapter sleeve 70 can be screwed onto the threaded section 66, which, together with the annular projection 60, serves to axially fix the pinion set 31.

[0070] Driver 60, adapter sleeve and the remaining pinions 33 of the pinion set 31 with the exception of the final pinion 36 can be designed in a conventional manner, for example as described in the document EP 3461731 A1.

[0071] When using a different, conventional adapter with an external toothing section that extends axially over a greater length, several pinions designed according to the invention can also be used as single pinions or insert pinions. The circumferential collar of the various pinions provided according to the invention can serve as a spacer, eliminating the need for separate spacer elements.

[0072] The following is based on the highly simplified flow chart in Figure 10 and the schematic representations of the Figures 11 to 13 An embodiment of a method according to the invention for producing a pinion according to the invention for a bicycle drive is explained. Optional steps are shown in the flow chart of Figure 10 marked by a dashed frame.

[0073] First, in a first step i), a pinion blank 34' is punched out of a sheet material. The punched pinion blank 34' comprises at least one central pilot hole 46'. This is preferably not circular but already has a plurality of radially inwardly projecting projections 50' (cf. Fig. 11 )

[0074] The pinion blank 34' is further processed into the actual pinion 34 in a further step ii).

[0075] The pinion blank 34' is first formed in a step a), whereby a punch 80 (cf. Fig. 12) is pressed through the pilot hole 46' of the pinion blank 34' into a die 82, so that an inner ring 44 with a central opening 46 and a circumferential collar 48 formed integrally with the inner ring 44 and projecting axially therefrom to one side are formed. The collar 48 is formed from material surrounding the central pilot hole 46' of the pinion blank 34' and defines the central opening 46 of the final pinion 34.

[0076] The cross-sectional shape of punch 80 and die 82 in a plane perpendicular to the central axis M is not round but is selected such that in step a), more precisely in a sub-step a1), an outer profile 49 with a plurality of radial recesses 52 and an inner profile 47 with a plurality of radially inwardly projecting radial projections 50 are formed on the collar 48, wherein the radial recesses 52 of the outer profile 49 and the radial projections 50 of the inner profile 47 correspond to one another in terms of number and arrangement.

[0077] If desired, the axial dimension a 48 (collar length) of the collar 48 can be adjusted more precisely in a subsequent forming step a2), in which the punch 82 used in step a1) is replaced by another punch 83, which has an additional forming surface 85 for defining the end face 48s of the collar 48. This also allows the flatness of the end face 48s to be adjusted. It may happen that this changes the radius of curvature of the transition from the inner ring 44 to the radial inside of the collar 48, as can be seen from a comparison of the Figures 12 and 13 emerges.

[0078] Finally, the shape of the inner profile of the collar can optionally be reworked, in particular recut, so that, for example, the Figure 7 The final shape of the inner profile 47, shown there in solid lines, is produced from the preform 51 indicated by a dashed line.

[0079] The method according to the invention enables a simple and inexpensive production of a pinion with good torque transmission properties.

Claims

1. Sprocket (34) for a bicycle drive (39), comprising: an outer ring (40) with an outer toothing (42) for engagement in a bicycle chain (30), an inner ring (44) which is disposed so as to be coaxial with and co-rotationally connected to the outer ring (40) and has a central opening (46), an encircling collar (48) which is formed so as to be integral to the inner ring (44) and projects axially to one side of the latter and is formed as a continuous collar, wherein provided on the radially inner side of the collar (48) is an inner profile (47) having a plurality of radial projections (50) which project radially inwards, wherein provided on the radially outer side of the collar (48) is an outer profile (49) having a plurality of radial depressions (52) which in terms of number and arrangement correspond to the radial projections (50) of the inner profile (47), characterized in that each of the radial projections (50) of the inner profile (47) has a first flank (50.1) which is disposed so as to lead in terms of a predefined rotation direction (D) about a central axis (M) of the sprocket (34), and a second flank (50.2) which is disposed so as to trail in terms of the predefined rotation direction (D), wherein, for at least one, preferably for each, of the radial projections (50) of the inner profile (47), the first (50.1) and the second flank (50.2) are not designed to be mutually mirror-symmetrical.

2. Sprocket (34) according to Claim 1, characterized in that the radial projections (50) of the inner profile (47) of the encircling collar (48) serve as entrainment elements which are designed to transmit torque from the sprocket (34) directly to a driver (60) on a rear wheel hub (17) of a bicycle (10).

3. Sprocket (34) according to Claim 2, characterized in that the first flank (50.1) of the at least one radial projection (50) of the inner profile (47) is designed to be radially longer than the second flank (50.2).

4. Sprocket (34) according to one of the preceding claims, characterized in that an axial end face (48s) of the encircling collar (48) is disposed axially between a central plane (E44) of the inner ring (44) and a central plane (E42) of the outer toothing (42) for engagement in a bicycle chain (30), or a central plane (E40) of the outer ring (40).

5. Sprocket cassette (32) for a bicycle drive (39), comprising a sprocket pack (31) having a plurality of coaxially disposed, axially mutually spaced apart and co-rotationally connected sprockets (33) with different diameters, wherein one of these sprockets is a final sprocket (36) which is designed to transmit torque directly to a driver (60) on a rear wheel hub (17) of a bicycle (10), characterized in that the final sprocket (36) is a sprocket (34) according to one of Claims 1 to 4.

6. Bicycle drive (39), comprising a driver (60) and at least one sprocket (34) according to one of Claims 1 to 4 and / or a sprocket cassette (32) according to Claim 5.

7. Method for producing a sprocket (34) for a bicycle drive (39), comprising the following method steps: i) stamping a sprocket blank (34') having a central pilot hole (46'); ii) further processing the sprocket blank (34) so as to form a sprocket (34) having a central opening (46), an inner ring (44) and an encircling collar (48) which is formed so as to be integral to the inner ring (44) and projects axially to one side of the latter; wherein step ii) comprises at least the following method step: a) forming the sprocket blank (34'), a punch being pressed through the pilot hole (46') of the sprocket blank (34) into a die to form the encircling collar (48); characterized in that, by way of the forming in step a), both an inner profile (47, 51) having a plurality of radial projections (50) which project radially inwards on the radially inner of the collar (48) is formed, as well as on the radially outer side of the collar (48) an outer profile (49) having a plurality of radial depressions (52) which in terms of number and arrangement correspond to the radial projections (50) of the inner profile (47).

8. Method according to Claim 7, characterized in that in step i) the central pilot hole (46') is formed in such a way that it has a plurality of radially inward-projecting projections (50') which in terms of number and arrangement correspond to the radially inward-projecting projections (50) of the inner profile (47) of the collar (48) formed in step ii).

9. Method according to Claim 7 or 8, characterized in that step ii) after step a) furthermore comprises the following step: b) post-machining the inner profile (47) of the encircling collar (48) produced by the forming process, preferably by cutting or milling.

10. Method according to Claim 9, characterized in that in step b) for at least one of the projections (50) of the inner profile (47), a first flank (50.1) of the projection (50), which is disposed so as to lead in terms of a selected rotation direction (D), and / or a second flank (50.2) of the projection (50), which is disposed so as to trail in terms of the selected rotation direction (D), are / is post-machined in such a way that, after post-machining, the first flank (50.1) is designed to be radially longer than the second flank (50.2).

11. Method according to one of Claims 7 to 10, characterized in that step a) furthermore comprises the following step: a2) forming the sprocket blank (34') or the sprocket (34) so that a predetermined axial dimension (a48) of the collar (48) is set.