Shaft-hub connection of a bottom bracket transmission of a bicycle or a pedelec

Abstract

The invention relates to a shaft-hub connection of a bottom bracket transmission (1), comprising a shaft component (3) and a hub component (4), wherein a running toothing (5) is provided for transmitting a torque, and an axial portion of the running toothing (5) is in the form of a driving toothing region (6). The invention further relates to a bicycle or a pedelec (2) having a bottom bracket transmission (1) with at least one shaft-hub connection.

Description

[0001] ZF Friedrichshafen AG File 306570 Friedrichshafen 2024-12-19

[0002] Shaft-hub connection of a pedal drive of a bicycle or pedelec

[0003] The present invention relates to a shaft-hub connection of a bottom bracket gearbox comprising a shaft component and a hub component, wherein a toothed gear is provided for torque transmission. The invention further relates to a bicycle or pedelec with a bottom bracket gearbox having at least one shaft-hub connection.

[0004] Shaft-hub connections are generally known, each comprising a shaft component and a hub component that must be connected to each other in a rotationally fixed manner to enable torque transmission or torque support. To achieve this rotationally fixed connection between the hub component and the shaft component, complex machining and, in some cases, additional components are required.

[0005] The present invention is based on the objective of proposing a shaft-hub connection of a bottom bracket gearbox and a bicycle or pedelec with a bottom bracket gearbox with a shaft-hub connection, which enable a structurally simple and cost-effective transmission or support of a torque.

[0006] This problem is solved according to the invention by the features of claim 1 or 11. Advantageous and claimed embodiments are described in the dependent claims, the description, and the drawings.

[0007] Thus, a shaft-hub connection of a bottom bracket gearbox is proposed, comprising a shaft component and a hub component, with a toothed raceway for torque transmission. To enable a structurally simple and cost-effective transmission or support of torque in the proposed shaft-hub connection, an axially extending section of the toothed raceway is designed as a drive tooth section or similar.

[0008] In this way, a shaft-hub connection is realized in a bottom bracket gearbox, in which the running gear teeth are also used as drive gear teeth (ZF Friedrichshafen AG File 306570 Friedrichshafen 2024-12-19). This advantageously saves on structurally complex redesigns and additional components.

[0009] For example, it is conceivable that the gear teeth are located on the outer circumference of the shaft component. This means that a corresponding gear toothing area located on the inner circumference of the hub component engages with the gear toothing area of ​​the gear teeth on the shaft component.

[0010] In another embodiment of the invention, the proposed shaft-hub connection may be provided with the gear teeth and the drive teeth on an inner circumference of the hub component. In this embodiment, a corresponding drive teeth on the outer circumference of the shaft component engages with the drive teeth of the gear teeth on the hub component.

[0011] If the proposed shaft-hub connection requires only a rotationally fixed connection between the shaft component and the hub component, it can be designed, for example, so that the tooth tip diameter of the gear teeth on the shaft component is slightly smaller than the tooth root diameter of a corresponding gear toothing area on the hub component. In other words, the tooth root diameter of the corresponding gear toothing area on the hub component is, for example, slightly larger than the tooth tip diameter of the gear teeth on the shaft component. This allows the shaft component and the hub component to be axially displaced relative to each other.

[0012] If the running gear with the drive gear area is provided on the inner circumference of the hub component, for axial displacement of the shaft component and hub component, it may be provided, for example, that a tooth tip diameter of the running gear with the drive gear area on the hub component is slightly larger than a tooth root diameter of a corresponding drive gear area on the shaft component. In other words, ZF Friedrichshafen AG File 306570 Friedrichshafen 2024-12-19

[0013] The tooth root diameter of the corresponding drive tooth area on the shaft component is, for example, slightly smaller than the tooth head diameter of the running tooth on the hub component.

[0014] If, in addition to the rotationally fixed connection between the shaft component and the hub component, axial support is also desired, a further embodiment of the invention can provide for an axial stop by means of a diameter step at the tooth tip or tooth root. In this way, a diameter step or a diameter shoulder on the running teeth or on the corresponding drive teeth area can be implemented as a mutual axial stop for the hub component and the shaft component in the proposed shaft-hub connection.

[0015] In order to also realize a stop on the opposite axial side, the invention provides that an axial locking element, preferably a snap ring or the like, is provided at one end of the drive tooth area facing away from the running toothing as an axial stop for the hub component or the shaft component.

[0016] The proposed shaft-hub connection can be used in any type of bottom bracket drive, such as reduction gears, spur gear drives, planetary gear sets, or the like. In one exemplary application of the shaft-hub connection, the shaft component can be configured as a sun gear or similar component of a planetary gear set within the bottom bracket drive, and the hub component as an inner ring of a freewheel, with an outer ring of the freewheel connected to a ring gear or similar component of the planetary gear set within the bottom bracket drive.

[0017] The freewheel can, for example, be a pawl freewheel as a freewheel clutch or as a freewheel brake.

[0018] In the proposed shaft-hub connection, the backlash or meshing clearance in the drive gear area and the meshing clearance in the running gear (ZF Friedrichshafen AG File 306570 Friedrichshafen 2024-12-19) can be configured differently. Backlash refers to the tolerance or clearance intentionally provided between the teeth of the gears. This results in advantages such as reduced torsional play or greater radial displacement under light loads. It is possible to select a smaller or larger meshing clearance for the drive gear area and the running gear.

[0019] The problem underlying the invention is also solved by a bicycle or pedelec with the bottom bracket gearbox with at least one shaft-hub connection as described above, resulting in the advantages already described and further advantages.

[0020] The present invention will now be explained in more detail with reference to the drawings.

[0021] They show:

[0022] Figure 1 shows a cutaway view of a possible embodiment of a shaft-hub connection according to the invention in a bottom bracket gearbox of a bicycle or pedelec;

[0023] Figure 2 is an enlarged detail view according to Figure 1;

[0024] Figures 3 to 5 show schematic views of embodiment variants with a running gear with a drive gear area on an outer circumference of a shaft component; and

[0025] Figures 6 to 8 show schematic views of design variants with the running gear with drive gear area on an inner circumference of a hub component.

[0026] Figures 1 to 8 show exemplary possible embodiments of a shaft-hub connection in a bottom bracket gearbox 1 of a bicycle or pedelec 2. ZF Friedrichshafen AG File 306570 Friedrichshafen 2024-12-19

[0027] The proposed shaft-hub connection is shown by way of example in a bottom bracket gearbox 1 designed as a planetary gear set. The shaft component 3 is designed as the sun gear of a planetary gear set 11 of the bottom bracket gearbox 1. The hub component 4 is designed as the inner ring of a freewheel 7.

[0028] In the embodiment shown in Figures 1 and 2, a toothed section 5 is provided on the outer circumference of the sun gear, which is designed as a shaft component 3. To achieve a structurally simple and cost-effective torque transmission between the shaft component 3 and the hub component 4, an axially extending section of the toothed section 5 on the outer circumference of the sun gear is designed as a drive tooth section 6. A corresponding drive tooth section 12 on the inner circumference of the inner ring of the freewheel 7, which is designed as a hub component 4, engages with the drive tooth section 6 of the toothed section 5 on the shaft component 3, so that the inner ring and the sun gear of the planetary gear set 11 are connected in a rotationally fixed manner via the drive tooth section 6 of the toothed section 5.

[0029] An outer ring 8 of the freewheel 7 is connected to a ring gear 9 of the planetary gear set 11 of the bottom bracket gearbox 1. In this way, in the locking direction of the freewheel 7, the ring gear 9 can be connected to the sun gear, designed as a shaft component 3, via the inner ring of the freewheel 7, designed as a hub component 4. In the illustrated embodiment, the freewheel 7 is designed as a freewheel clutch. The freewheel clutch connects two rotatable components to each other in the locking direction.

[0030] In order to provide axial support between the sun gear (designed as shaft component 3) and the inner ring (designed as hub component 4) in the embodiment shown in Figures 1 and 2, in addition to the rotationally fixed connection, a diameter step 10 is provided on a tooth tip of the running gear 5 as an axial stop. This results in a tooth tip diameter step 10 between the running gear 5 and the drive gear section 6, which serves as an axial stop for the inner ring on the sun gear. The tooth root diameter of the hub component 4 is smaller than the tooth tip diameter of the running gear section 5 of the shaft component 3. ZF Friedrichshafen AG File 306570 Friedrichshafen 2024-12-19

[0031] The various possible designs regarding the arrangement of the running gear 5 on the shaft component 3 or on the hub component 4, as well as regarding the diameter step 10 on the running gear 5 or on the corresponding drive gear area 12, are shown schematically in Figures 3 to 8.

[0032] In Figures 3 to 5, the running gear 5 with the drive gear section 6 is provided on the outer circumference of the shaft component 3. Figures 4 and 5 show different possibilities for realizing the diameter step 10. In Figure 4, the diameter step 10 is provided in the tooth tip of the running gear 5 on the shaft component 3, wherein the tooth root diameter of the hub component 4 is smaller than the tooth tip diameter of the shaft component 3. In Figure 5, the diameter step 10 is provided in the tooth tip of the corresponding drive gear section 12 on the hub component 4, wherein the tooth tip diameter of the hub component 4 is smaller than the tooth root diameter of the shaft component 3.

[0033] Figures 6 to 8 show the running gear 5 with the drive gear section 6 on the inner circumference of the hub component 4. Figures 7 and 8 show different possibilities for realizing the diameter step 10. In Figure 7, the diameter step 10 is provided in the tooth head of the running gear 5 on the hub component 4, wherein the tooth head diameter of the hub component 4 is smaller than the tooth root diameter of the shaft component 3. In Figure 8, the diameter step 10 is provided in the tooth head of the corresponding drive gear section 12 on the shaft component 3, wherein the tooth root diameter of the hub component 4 is smaller than the tooth head diameter of the shaft component 3.

[0034] Axial support can also be achieved in the same way by means of a diameter shoulder or a diameter step 10 in the tooth root of the running gear 5 or the corresponding drive gear area 12. ZF Friedrichshafen AG File 306570 Friedrichshafen 2024-12-19

[0035] Reference mark

[0036] 1 bottom bracket gearbox

[0037] 2 Bicycle or pedelec

[0038] 3 shaft component

[0039] 4 Hub component

[0040] 5 Running gear

[0041] 6 Drive gear area

[0042] 7 Freewheel

[0043] 8 Outer ring of the freewheel

[0044] 9 Ring gear of the planetary gear set

[0045] 10 diameter step as axial stop

[0046] 11 Planetary gear set

[0047] 12 corresponding drive gear area

Claims

ZF Friedrichshafen AG File 306570 Friedrichshafen 2024-12-19 Patent claims 1. Shaft-hub connection of a bottom bracket gearbox (1 ) with a shaft component (3) and with a hub component (4), wherein a running toothing (5) is provided for torque transmission, characterized in that an axial section of the running toothing (5) is designed as a drive toothing area (6).

2. Shaft-hub connection according to claim 1, characterized in that the running toothing (5) with the drive toothing area (6) is provided on an outer circumference of the shaft component (3).

3. Shaft-hub connection according to claim 1 or 2, characterized in that the running toothing (5) with the drive toothing area (6) is provided on an inner circumference of the hub component (4).

4. Shaft-hub connection according to claim 2, characterized in that a tooth head diameter of the running toothing (5) with the drive toothing area (6) on the shaft component (3) is slightly smaller than a tooth root diameter of a corresponding drive toothing area (12) on the hub component (4).

5. Shaft-hub connection according to claim 3, characterized in that a tooth head diameter of the running toothing (5) with the drive toothing area (6) on the hub component (4) is slightly larger than a tooth root diameter of a corresponding drive toothing area (12) on the shaft component (3).

6. Shaft-hub connection according to claim 4 or 5, characterized in that a diameter step (10) is provided as an axial stop on a tooth head or tooth root of the running toothing (5) or on the corresponding drive toothing area (12).

7. Shaft-hub connection according to one of the preceding claims, characterized in that an axial locking element is provided at one end of the drive toothing area (6) facing away from the running toothing (5) as an axial stop for the hub component (4) or the shaft component (3). ZF Friedrichshafen AG File 306570 Friedrichshafen 2024-12-19 8. Shaft-hub connection according to one of the preceding claims, characterized in that the shaft component (3) is designed as a sun gear of a planet gear set (11) of the bottom bracket gear (1) and the hub component (4) is designed as an inner ring of a freewheel (7), wherein an outer ring (8) of the freewheel (7) is connected to a ring gear (9) of the planet gear set (11) of the bottom bracket gear (1).

9. Shaft-hub connection according to claim 8, characterized in that the freewheel (7) is designed as a freewheel clutch.

10. Shaft-hub connection according to one of the preceding claims characterized in that the clearance in the drive toothing area (6, 12) and the clearance in the running toothing (5) are designed differently.

11. Bicycle or pedelec (2) with a bottom bracket gearbox (1) with at least one shaft-hub connection according to one of the preceding claims.

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