Transmission arrangement for a vehicle that can be operated at least partially by muscle power

Abstract

The invention relates to a transmission arrangement for a vehicle that can be operated at least partially by muscle power. The transmission arrangement has an input element (4), a planetary gear set (10), and an output element (5). The input element (4) is designed to input a driving force. The input element (4) is mechanically operatively connected to the output element (5) via the planetary gear set (10) in order to output a driving force. A planetary carrier (12) of the planetary gear set (10) is mounted on a hollow shaft (25) of the transmission arrangement via a first bearing unit (61). The planetary carrier (12) is mounted on the output element (5) via a second bearing unit (62). A center of gravity of the planetary carrier (12) in the axial direction is arranged within a bearing region which extends in the axial direction from the first bearing unit (61) to the second bearing unit (62).

Description

[0001] ZF Friedrichshafen AG File 306577 Friedrichshafen 2024-12-19

[0002] Gearbox arrangement for a vehicle that can be operated at least partially by muscle power

[0003] The present invention relates to a transmission arrangement for a vehicle that can be operated at least partially by muscle power, to a drive device with a transmission arrangement and to a vehicle with a drive device.

[0004] Gear systems for bicycles are well-known. With the increasing complexity of these gear systems and the growing number of components and parts used in them, the costs and manufacturing effort also increase. From an ecological perspective alone, it is desirable for such a gear system to have a long service life.

[0005] It is an object of the present invention to provide an improved drive unit that has a long service life.

[0006] The problem is solved by the subject matter with the features of the independent patent claims. Advantageous further developments are the subject of the dependent claims.

[0007] The first aspect describes a transmission arrangement for a vehicle that can be propelled at least partially by muscle power. The vehicle can be a bicycle, e-bike, or pedelec. The transmission arrangement can be a bottom bracket gearbox. It comprises an input element, a planetary gear set, and an output element. The input element is designed to input a drive force. It is mechanically connected to the output element via the planetary gear set. The input element can also be mechanically connected to the output element via additional transmission elements, such as further gear sets or planetary gear sets. The output element is designed to output a drive force. It can be a gear, a sprocket, or a pulley.A planet carrier of the planetary gear set is mounted on a hollow shaft of the transmission assembly via a first bearing unit (ZF Friedrichshafen AG file 306577, Friedrichshafen, 2024-12-19), for example, in a radial direction. The planet carrier is mounted on the output element via a second bearing unit. The center of gravity of the planet carrier is located axially within a bearing area that extends axially from the first bearing unit to the second bearing unit.

[0008] The input element can be designed as a crankshaft. At least one crank arm can be fixedly connected to the input element at one end in an axial direction. The input element can have an axis of rotation about which it is rotatable. The axis of rotation can be oriented axially. A radial direction can be oriented substantially perpendicular to the axial direction. A circumferential direction can be oriented around the axis of rotation. The input element can extend axially through the hollow shaft, the planet carrier, and the output element. The input element, the hollow shaft, the output element, and the planet carrier can be arranged coaxially.

[0009] The driving force can be applied by a rider at the crank arm in the form of pedaling force. The driving force can be input into the transmission assembly via the input element. The driving force can be present at the input element in the form of torque. The transmission assembly can provide one or more gear ratios between the input element and the output element. Gear ratios can be switchable, for example, via at least one switching element. The transmission assembly can be designed as a summing transmission.

[0010] If two elements are mechanically connected, they are coupled to each other directly or indirectly in such a way that a movement of one element causes a reaction of the other element. For example, a mechanical connection can be provided by a positive-locking or friction-locking connection. The mechanical connection can correspond to the meshing of corresponding gear teeth of the two elements. Further elements, such as one or more [ZF Friedrichshafen AG File 306577 Friedrichshafen 2024-12-19], can be located between the elements.

[0011] Spur gear stages are provided. A permanently non-rotatable connection between two elements, on the other hand, is understood to be a connection in which the two elements are rigidly coupled to each other in all intended states of the transmission. The elements can be individual components rigidly connected to each other or even a single piece. A non-rotatable connection between two elements can be selectively established or disengaged via a switching element, such as a clutch or brake.

[0012] The planetary gear set can comprise a sun gear, a planet carrier, a number of planet pins, a number of planet gears, and a ring gear. The planet pins can be attached to the planet carrier. Each planet pin can rotatably mount a planet gear. At least one of the planet gears can mesh with both the sun gear and the ring gear. The planetary gear set can be configured as a positive or negative planetary gear set. The sun gear can have spur gear teeth. The sun gear can also have at least one pawl pocket for receiving at least one pawl of a freewheel. The transmission assembly can include another planetary gear set. This additional planetary gear set can be constructed as described above with reference to the planetary gear set.

[0013] Both the first and second bearing units can be arranged radially on an inner side of the planet carrier, for example, on an inner circumference. The bearing area can be arranged radially on an inner section of the planet carrier. The bearing area can encompass the first and second bearing units axially. The bearing area can be designed to be wide and positioned axially such that the center of gravity of an assembly comprising the planet carrier and at least one of the ring gears, or a switching element (for example, for locking the sun gear), is located axially within the bearing area. The switching element can be designed as a pawl or a brake. The switching element can be arranged axially in the same plane as the bearing area.The bearing area can be designed in such a way that all forces, in particular a braking force or gravity of the switching element, are transferred via the first ZF Friedrichshafen AG file 306577 Friedrichshafen 2024-12-19.

[0014] The bearing unit and the second bearing unit can be supported without significant tilting of the planet carrier. This allows for gentle operation of the planetary gear set, for example with a uniform contact pattern of the teeth and / or a homogeneous distribution of tooth forces in the respective engagements.

[0015] At least one of the first and second bearing units can be a radial bearing, a rolling bearing, or a plain bearing. At least one of the first and second bearing units can have a rotationally fixed bearing unit, for example, a drive connection.

[0016] The hollow shaft can be formed by a gear set element of the further planetary gear set. The gear set element can be, for example, a sun gear, a ring gear, or a planet carrier. The hollow shaft can be rotatably mounted on the input element via a hollow shaft bearing unit. The hollow shaft bearing unit can be designed as a plain bearing. In this case, the hollow shaft can form a sliding surface on its inner circumference. The input element can form a sliding surface on its outer circumference. Each sliding surface can be formed by a protrusion, for example, on an outer circumference in the radial direction. The sliding surface of the hollow shaft and the sliding surface of the input element can be designed for sliding contact with each other. The sliding surface for the hollow shaft bearing unit and a rolling surface or sliding surface for the first output bearing unit of the input element can be formed by a common cylindrical surface.

[0017] In one embodiment of the transmission arrangement, the first bearing unit can mount the planet carrier to the hollow shaft in a rotationally fixed manner. The first bearing unit can be configured as a drive connection. The drive connection can have at least one of the following: a drive tooth, a splined shaft connection, or a keyed shaft connection. The planet carrier can be mounted to and on the hollow shaft in a rotationally fixed manner via the first bearing unit. ZF Friedrichshafen AG File 306577 Friedrichshafen 2024-12-19

[0018] In one embodiment of the gear arrangement, the first bearing unit can have a drive tooth. The first bearing unit can be designed as a drive tooth.

[0019] In one embodiment of the transmission arrangement, the second bearing unit can have a plain bearing. The planet carrier can have a sliding surface on its inner circumference. The output element can have a sliding surface, for example, on its outer circumference. The sliding surface can be formed by a radial projection, for example, on its outer circumference. The sliding surface of the planet carrier and the sliding surface of the output element can be designed to slide in contact with each other. The plain bearing can be formed by the sliding surface of the planet carrier and the sliding surface of the output element. The plain bearing can have a plain bearing bushing or plain bearing shell and can, for example, be pressed into the planet carrier. The output element can be in constant rotation during operation as soon as the vehicle starts moving.This allows a hydrodynamic operating condition to be achieved in the second bearing unit between the planet carrier and the output element during operation. This can reduce wear and drag torque in the second bearing unit and extend the service life of the transmission assembly.

[0020] In one embodiment of the gear arrangement, the plain bearing can have the sliding surface of the planet carrier and the sliding surface of the output element, which are designed for sliding contact with each other. In one embodiment of the gear arrangement, the planet carrier can be made of uncoated aluminum. The sliding surface of the output element can have an anodized surface. The sliding surface of the output element can be hard anodized. The entire surface of the output element can be hard anodized. This can increase both the corrosion resistance of the area of ​​the output element located outside the stationary component and improve the tribological properties of the sliding surface.

[0021] In one embodiment of the gear arrangement, the output element can be accessed via a

[0022] The output bearing unit must be rotatably mounted relative to the input element. ZF Friedrichshafen AG File 306577 Friedrichshafen 2024-12-19

[0023] The output element can be supported on the input element via a first output bearing unit and a second output bearing unit. The first and second output bearing units can be identical. At least one of the first and second output bearing units can have a radial bearing, for example, a needle bearing, for example, with an outer ring. The first output bearing unit can be arranged axially in the same plane as the bearing area of ​​the first and second bearing units. The first output bearing unit can also be arranged axially in the same plane as the second bearing unit.

[0024] The first and second output bearing units can be arranged axially offset from each other. The second output bearing unit can be offset in the opposite direction to the first bearing unit, for example, towards a main bearing unit. The first and second output bearing units can form a bearing area for the output element. The bearing area for the output element can be designed to reduce or prevent tilting of the output element. This ensures coaxiality of the output element with the input element and the gear set elements of the planetary gear set.

[0025] The output element can be rotatably mounted in a stationary component via a main bearing unit. The stationary component can be a gearbox housing or a bicycle frame. The main bearing unit can include a rolling bearing, for example, a deep groove ball bearing. The main bearing unit can be located radially outside of the second output bearing unit. The main bearing unit can be located axially in the same plane as the second output bearing unit. The main bearing unit can form a common main bearing unit for both the input and output elements. The input element can be rotatably mounted on the stationary component via the second output bearing unit, the output element, and the main bearing unit.

[0026] In one embodiment of the gear arrangement, the planet carrier can have at least one pawl pocket for receiving a pawl of a freewheel. ZF Friedrichshafen AG File 306577 Friedrichshafen 2024-12-19

[0027] The planet carrier can have multiple latch pockets. The latch pockets can be arranged circumferentially, for example, evenly spaced. Alternatively, the latch pockets can be arranged circumferentially, for example, unevenly spaced. The latch pockets can be designed as recesses or depressions. The latch pockets can extend axially or be recessed axially from a reference surface. A latch can be pivotally mounted in the latch pocket. The latch can, for example, be pivotally mounted circumferentially. The latch pocket can be designed to allow the latch to pivot. The latch pocket can be arranged axially in the same plane as the first bearing unit.

[0028] In one embodiment of the gear arrangement, the pawl pocket in the planet carrier can be arranged axially in the same plane as the first bearing unit and radially outside the first bearing unit. The first bearing unit can be configured as a drive gear.

[0029] In a second aspect, a drive device with a gear arrangement according to one of the preceding embodiments is provided. Further features, effects, and advantages for the second aspect can be derived from the first aspect. Furthermore, features, effects, and advantages of the second aspect also constitute features, effects, and advantages for the first aspect. The drive device further comprises at least one pedal crank that is rotationally fixed to the input element.

[0030] The drive device can have two crank arms. One crank arm can be attached to each end in the axial direction of the input element. The two crank arms can be arranged opposite each other with respect to the input element. A pedal can be attached to each crank arm at one outer end in the radial direction. A rider can apply pedaling force or pulling force to the crank arm via the pedal. The pedaling force and / or pulling force can be directly converted into a torque in the input element via the crank arm. ZF Friedrichshafen AG File 306577 Friedrichshafen 2024-12-19

[0031] The drive device can include a motor with a drive shaft that is mechanically connected to the output element via a transmission gear in the gearbox assembly. The motor can be an electric motor, for example, a synchronous or asynchronous motor. The motor can have a stator and a rotor. The rotor can form the drive shaft. A driving force, for example, a torque, can be output via the drive shaft. The drive shaft can be mechanically connected to the output element via the transmission gear.

[0032] The transmission arrangement can be designed as a summing transmission. The transmission arrangement can be designed to summate a mechanical drive force, for example, the torque from the pedaling force and / or traction force, and a supporting drive force from the motor, for example, an electric drive force from the electric motor. The transmission can comprise at least one planetary gear set, a spur gear set, and a belt drive, belt drive, chain drive, or chain drive. The transmission can be designed to reduce rotational speed and increase torque from the rotor to the output element and, for example, have a high gear ratio.

[0033] In a third aspect, a vehicle with a drive device according to the second aspect is provided. Further features, advantages, and effects for the third aspect can be derived from one of the preceding aspects. Furthermore, features, advantages, and effects of the third aspect also constitute features, advantages, and effects for the preceding aspects. The vehicle is at least partially propelled by muscle power. The vehicle has at least one traction element for propelling the vehicle, which is mechanically connected to the output element. The traction element may be formed by a drive wheel.

[0034] The traction element can be mechanically connected to the output element via an output transmission, for example, a chain drive, a belt drive, or a belt drive. The vehicle may have other equipment, such as a steering system and a braking system. ZF Friedrichshafen AG File 306577 Friedrichshafen 2024-12-19

[0035] Figure 1 is a sectional view of a schematic representation of an embodiment of a transmission arrangement for a vehicle that can be operated at least partially by muscle power.

[0036] Figure 2 is a sectional view of a schematic representation of another embodiment of the gear arrangement.

[0037] Figure 3 is a side view of a schematic representation of the vehicle, which can be operated at least partially by muscle power.

[0038] Figure 1 is a sectional view of a schematic representation of an embodiment of a transmission arrangement for a vehicle that is at least partially powered by muscle power. The vehicle is designed as an e-bike. The transmission arrangement comprises a planetary gear set 10 with a sun gear 11, a planet carrier 12, a number of planet pins 13, a number of planet gears 14, and a ring gear 15. Each of the planet gears 14 is rotatably mounted on the planet carrier 12 via one of the planet pins 13. The planet carrier 12 has pawl pockets 31 for pawls of a freewheel 30. At least one of the planet gears 14 is engaged with both the sun gear 11 and the ring gear 15. The transmission arrangement has an input element 4 for applying a drive force, which, along with other transmission elements not shown, is mechanically connected via the planetary gear set 10 to an output element 5 for outputting a drive force.The input element 4 is designed as a pedal crank shaft. The output element 5 is designed as a chainring or belt pulley, or as a shaft with an interface to a chainring or belt pulley located outside the stationary component 9. The transmission assembly has a switching element 72, which in this case is designed as a brake pawl. The sun gear 11, which engages with a locking ring 73 via a locking contour 71, can be locked to a stationary component 9 via the switching element 72. The locking ring 73 is designed as a brake ring.

[0039] The planet carrier 12 is radially supported on a hollow shaft 25 via a first bearing unit 61 and on the output element 5 via a second bearing unit 62. The first bearing unit 61 is formed by a drive connection which has drive teeth. Thus, the planet carrier 12 is supported via the first bearing unit 61. (ZF Friedrichshafen AG File 306577 Friedrichshafen 2024-12-19)

[0040] Bearing unit 61 is rotationally fixed to and mounted on the hollow shaft 25. The second bearing unit 62 has a plain bearing formed by a sliding surface of the output element on an outer circumference and by a sliding surface of the planet carrier 12 on an inner circumference, which are designed for sliding contact with each other. The first bearing unit 61 and the second bearing unit 62 form a bearing area. The center of gravity of an assembly comprising the planet carrier 12, the planet pins 13, the planet gears 14, the ring gear 15, and the locking ring 73 is located axially within the bearing area. This design ensures that all forces, in particular a braking force of the locking ring 73 (which can be locked by means of an inserted switching element 72) or a gravitational force on the assembly, can be supported via the first bearing unit 61 and the second bearing unit 62 without tilting the planet carrier 12.

[0041] The output element 5 is rotatably mounted relative to the input element 4 via a first output bearing unit 63 and a second output bearing unit 64. The first output bearing unit 63 and the second output bearing unit 64 are each designed as needle bearings with an outer ring. The first output bearing unit 63 is arranged axially in the same plane as the second bearing unit 62. The second output bearing unit 64 is axially offset outwards relative to the first output bearing unit 63. The first output bearing unit 63 and the second output bearing unit 64 form a bearing area for the output element 5 and prevent it from tilting. The output element 5 is rotatably mounted in the stationary component 9 via a main bearing unit 66.The main storage unit 66 forms a common storage unit for the output element 5 and the input element 4, which is stored in the stationary component 9 via the second output storage unit 64, the output element 5 and the main storage unit 66.

[0042] The hollow shaft 25 is rotatably mounted to the input element 4 via a hollow shaft bearing unit 65. The hollow shaft bearing unit 65 is designed as a plain bearing, formed by a sliding surface of the input element 4 on an outer circumference and by a sliding surface of the hollow shaft 25 on an inner circumference. The sliding surface of the input element 4 and the sliding surface of the hollow shaft ZF Friedrichshafen AG File 306577 Friedrichshafen 2024-12-19

[0043] The 25 components are designed for sliding contact with each other. The sliding surface for the hollow shaft bearing unit 65 and a rolling surface for the first output bearing unit 63 of the input element 4 are formed by a common cylindrical surface.

[0044] Figure 2 is a sectional view of a schematic representation of another embodiment of the gear arrangement. The present embodiment differs from the embodiment shown with reference to Figure 1 in that the second bearing unit 62 has a sliding bearing formed by a sliding ring pressed into the planet carrier 12. In this respect, a sliding surface of the sliding ring on an inner circumference and the sliding surface of the output element 5 are designed to engage with each other.

[0045] Figure 3 is a side view of a schematic diagram of the vehicle, which can be propelled at least partially by muscle power. The output element 5 is mechanically connected via a chain drive to a traction element 1 designed as a drive wheel. The input element 4 can be mechanically driven via two pedal cranks 3. The transmission arrangement is designed as a bottom bracket transmission.

[0046] ZF Friedrichshafen AG File 306577 Friedrichshafen 2024-12-19

[0047] Reference mark

[0048] 1 traction element

[0049] 3 Crankshaft

[0050] 4. Entrance element

[0051] 5 Starting element

[0052] 9 Stationary component

[0053] 10 planetary gear set

[0054] 11 Sun wheel

[0055] 12 planetary carriers

[0056] 13 planetary bolts

[0057] 14 planetary gear

[0058] 15 Ring gear

[0059] 25 Hollow shaft

[0060] 30 Freewheel

[0061] 31 Jack pocket

[0062] 61 First storage unit

[0063] 62 Second storage unit

[0064] 63 First output storage unit

[0065] 64 Second output storage unit

[0066] 65 Hollow shaft bearing unit

[0067] 66 Main storage unit

[0068] 71 Locking contour

[0069] 72 Switching element

[0070] 73 Locking ring

Claims

ZF Friedrichshafen AG File 306577-DE-NP Friedrichshafen Ref. 102024212153.3 2025-03-18 Patent claims 1. Gear arrangement for a vehicle that can be operated at least partially by muscle power, wherein the gear arrangement comprises: an input element (4) for inputting a drive force, wherein the input element (4) is mechanically connected via a planetary gear set (10) to an output element (5) for outputting a drive force, and a planet carrier (12) of the planetary gear set (10) is mounted on a hollow shaft (25) of the gear arrangement via a first bearing unit (61) and is mounted on the output element (5) via a second bearing unit (62), wherein a center of gravity of the planet carrier (12) is arranged in the axial direction within a bearing area which extends in the axial direction from the first bearing unit (61) to the second bearing unit (62).

2. Gear arrangement according to claim 1, characterized in that the first bearing unit (61) supports the planet carrier (12) in a rotationally fixed manner with the hollow shaft (25).

3. Gear arrangement according to claim 2, characterized in that the first bearing unit (61 ) has a drive toothing.

4. Gear arrangement according to one of the preceding claims, characterized in that the second bearing unit (62) has a sliding bearing.

5. Gear arrangement according to claim 4, characterized in that the sliding bearing has a sliding surface of the planet carrier (12) and a sliding surface of the output element (5) which are designed for sliding contact with each other.

6. Gear arrangement according to claim 5, characterized in that the planet carrier (12) is made of uncoated aluminium and the sliding surface of the output element (5) has an anodised surface. - Alternative page - ZF Friedrichshafen AG File 306577-DE-NP Friedrichshafen Ref. 102024212153.3 2025-03-18 7. Gear arrangement according to one of the preceding claims, characterized in that the output element (5) is rotatably mounted to the input element (4) via an output bearing unit (63, 64).

8. Gear arrangement according to one of the preceding claims, characterized in that the pawl pocket (31 ) in the planet carrier (12) is arranged in the axial direction in the same plane as the first bearing unit (61 ) and in a radial direction outside the first bearing unit (61 ).

9. Drive device with a gear arrangement according to one of the preceding claims and at least one pedal crank (3) which is non-rotatably connected to the input element (4).

10. Vehicle that can be operated at least partially by muscle power, comprising a drive device according to claim 9 and at least one traction element (1 ) for moving the vehicle, which is mechanically connected to the output element (5). - Alternative page -

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