DE102020128385A1 - Drive system for a motor-assisted bicycle - Google Patents

Abstract

The invention relates to a drive system (1) for a motor-assisted bicycle (2), comprising a shaft (4) driven by at least one crank (3) and a first electric machine (5) with a generator rotor (6) and a generator -Stator (7), whereby the shaft (4) driven by the crank (3) is geared to the generator rotor (6) and a second electric machine (8) with a motor, which is electrically connected to the first electric machine (5). - Rotor (9) and motor stator (10), wherein the second electrical machine (8) is coupled to a wheel (11) of the bicycle (2), so that rotation of the crank (3) in the direction of travel generates electrical power is generated in the first electrical machine (5), which can be transmitted via an electrical line (12) to the second electrical machine (8), which converts the electrical power into mechanical drive power of the wheel (11), the crank (3rd ) non-rotatably on the shaft (4) is arranged and the shaft (4) has a crank connection (13) which is designed as a 5-edge, with an adapter sleeve (14) being arranged between the crank (3) and the crank connection (13) of the shaft (4), which is positively coupled on the inside with the crank connection (13) of the shaft (4) designed as a 5-point and on the outside positively with the crank (3).

Description

The present invention relates to a drive system for a motor-assisted bicycle, comprising a shaft driven by at least one crank and a first electric machine with a generator rotor and a generator stator, the shaft driven by the crank being geared to the generator rotor and a second electric machine electrically connected to the first electric machine with a motor rotor and motor stator, the second electric machine being coupled to a wheel of the bicycle so that rotation of the crank in the direction of travel generates electric power in the first electrical machine is generated, which can be transmitted via an electrical line to the second electrical machine, which converts the electrical power into mechanical drive power of the wheel.

Drive systems for motor-assisted bicycles are known from the prior art, in which a generator converts the biomechanical drive power of a user into electrical power, which is then converted back into mechanical drive power by a drive motor connected to a wheel. Since the transmission from the crank driven by the user to the driven wheel does not take place by means of a chain, as is usually the case, but electrically, the term "electric chain" is often used in this context.

It is the object of the invention to further develop a drive system for motor-assisted bicycles such that a large number of different cranks available on the market can be used with the drive system.

This object is achieved by a drive system for a motor-assisted bicycle, comprising a shaft driven by at least one crank and a first electric machine with a generator rotor and a generator stator, the shaft driven by the crank being geared to the generator rotor and a second electrical machine electrically connected to the first electrical machine with a motor rotor and motor stator, the second electrical machine being coupled to a wheel of the bicycle, so that rotation of the crank in the direction of travel generates electrical power in the first electrical machine is generated, which can be transmitted via an electrical line to the second electrical machine, which converts the electrical power into mechanical drive power of the wheel, with the crank being arranged on the shaft in a rotationally fixed manner and the shaft having a crank connection which is used as the 5th -Kant trained t, with an adapter sleeve being arranged between the crank and the crank connection of the shaft, which is positively coupled on the inside to the crank connection of the shaft, which is designed as a 5-edge, and on the outside, positively coupled to the crank.

The adapter sleeve thus makes it possible to use different crank systems in the drive system according to the invention. The market includes cranks with a so-called ISIS connection known, which require a comparatively large outer shaft diameter. However, a larger outer shaft diameter would enlarge the construction of the first electrical machine radially outwards. This would make the second electrical machine larger, more visually striking and also heavier, which would entail significant disadvantages for broad market acceptance.

In principle, the adapter sleeve can also be used for a central motor, which is still very common for conventional pedelecs today.

According to an advantageous embodiment of the invention, it can be provided that the crank is arranged on the shaft protruding axially from the first electrical machine.

According to a further preferred further development of the invention, it can also be provided that two cranks are provided, which are each arranged on both sides of the shaft.

Furthermore, according to a likewise advantageous embodiment of the invention, it can be provided that the adapter sleeve has a toothed profile on the outside, in particular an ISIS profile.

According to a further particularly preferred embodiment of the invention, provision can be made for the crank to have an opening which at least partially encompasses the adapter sleeve in a form-fitting manner.

It can also be preferred that the first electrical machine has a planetary gear which is coupled to the crank on the input side and to the generator rotor on the output side. This machine-gear arrangement, which can also be combined to form a structural unit, should preferably be coaxial so that, among other things, a round installation diameter can result. Cranks with a so-called ISIS connection known, which require a comparatively large outer shaft diameter. However, a larger outer shaft diameter would enlarge the complete machine-transmission construction radially outwards. The use of a small sun wheel would then help For example, this is then no longer possible and in order to keep the gear ratio in the desired range, the entire planetary gearset including the ring gear would have to be enlarged radially outwards, which can be avoided by using the adapter sleeve described above.

Finally, it may also be preferable for the crank connection of the shaft to be conical in shape and for the adapter sleeve to be conically shaped to correspond to this on the inside. This makes it possible to create a play-free connection between the adapter sleeve and the crank connection.

The invention will be explained in more detail below with reference to figures without restricting the general inventive idea.

• 1 Ein motorisch unterstütztes Fahrrad mit einem Antriebssystem,
• 2 eine erste elektrische Maschine mit Kurbeln in einer Frontalansicht,
• 3 eine Axialschnittansicht durch eine erste elektrische Maschine,
• 4 eine perspektivische Explosionsdarstellung einer ersten elektrischen Maschine mit einer Kurbel, und
• 5 eine Adapterhülse in einer Aufsicht.

Show it:

• 1 A motor-assisted bicycle with a drive system,
• 2 a first electric machine with cranks in a front view,
• 3 an axial section through a first electrical machine,
• 4 an exploded perspective view of a first electrical machine with a crank, and
• 5 an adapter sleeve in a top view.

the 1 shows a drive system 1 for a motor-assisted bicycle 2, the drive system 1 being shown in a schematic block diagram in the lower illustration. The drive system 1 comprises a shaft 4 driven by at least one crank 3 and a first electric machine 5 with a generator rotor 6 and a generator stator 7, the shaft 4 driven by the crank 3 being geared to the generator rotor 6 and a second electrical machine 8 with a motor rotor 9 and motor stator 10 electrically connected to the first electrical machine 5. The first electrical machine 5 is also in FIG 2 pictured.

The second electrical machine 8 is coupled to a wheel 11 of the bicycle 2, so that rotating the crank 3 in the direction of travel generates electrical power in the first electrical machine 5, which is transmitted via an electrical line 12 to the second electrical machine 8 can be transmitted, which converts the electrical power into a mechanical drive power of the wheel 11 . This is good from the synopsis of the top figure and the bottom figure 1 apparent.

The details of the crank connection are based on the 3 now explained in more detail below. The crank 3 is arranged on the shaft 4 in a rotationally fixed manner. The shaft 4 has a crank connection 13 which is designed as a 5-sided. An adapter sleeve 14 is arranged between the crank 3 and the crank connection 13 of the shaft 4 , which is positively coupled to the crank connection 13 of the shaft 4 embodied as a pentagon on the inside and positively coupled to the crank 3 on the outside. In the embodiment shown, the adapter sleeve 14 has a 10-tooth ISIS profile on the outside. This is particularly good once again based on the representation in the 5 recognizable. The shaft connection 13 designed as a 5-edged shape fits very well into the profile of the 10-tooth ISIS geometry, so that the adapter sleeve 14 still has a sufficiently large wall thickness.

The crank 3 is arranged on the shaft 4 protruding axially from the first electrical machine 5 . Of the 3 it is also easy to see that two cranks 3 can be provided, which are each arranged on either side of the shaft 4 . The crank connection 13 of the shaft 4 is conical and the adapter sleeve 14 is correspondingly conical on the inside in order to produce freedom from play.

A central screw 16 is provided for axial attachment or to ensure a play-free fit. This screw 16 also secures the crank 3 in the closest position. This prevents the crank 3 from protruding too far axially. Alternatively or additionally, it would also be possible for the crank 3 to be clamped radially in that the crank hubs have a slot that is clamped using two screws. This is particularly the case in the presentation of 4 recognizable.

The first electrical machine 5 has a planetary gear 15 which is coupled to the crank 3 on the input side and to the generator rotor 6 on the output side. The planetary gear 15 and the generator stator 7 and the generator rotor 6 are arranged in a common housing.

The invention is not limited to the embodiments shown in the figures. The foregoing description is therefore not to be considered as limiting but as illustrative. The following patent claims are to be understood in such a way that a mentioned feature is present in at least one embodiment of the invention. This does not exclude the presence of other features. Insofar as the patent claims and the above description define 'first' and 'second' features, this designation serves as sub Distinguishing between two characteristics of the same type without specifying a ranking.

Reference List

1

drive system

2

bicycle

3

crank

4

Wave

5

electric machine

6

generator rotor

7

generator stator

8th

electric machine

9

motor rotor

10

motor stator

11

wheel

12

electrical line

13

crank connection

14

adapter sleeve

15

planetary gear

Claims (7)

Drive system (1) for a motor-assisted bicycle (2), comprising a shaft (4) driven by means of at least one crank (3) and a first electrical machine (5) with a generator rotor (6) and a generator stator (7 ), wherein the shaft (4) driven by the crank (3) is coupled in a geared manner to the generator rotor (6) and to a second electric machine (8) which is electrically connected to the first electric machine (5) and has a motor rotor ( 9) and motor-stator (10), wherein the second electrical machine (8) is coupled to a wheel (11) of the bicycle (2), so that by turning the crank (3) in the direction of travel, electrical power is generated in the first electrical machine (5) is generated, which can be transmitted via an electrical line (12) to the second electrical machine (8), which converts the electrical power into mechanical drive power of the wheel (11), characterized in that the crank (3rd ) non-rotatably on the shaft (4). is arranged and the shaft (4) has a crank connection (13) which is designed as a 5-edged edge, with an adapter sleeve (14) being arranged between the crank (3) and the crank connection (13) of the shaft (4), which is positively coupled on the inside with the crank connection (13) of the shaft (4) designed as a 5-point and on the outside positively with the crank (3). Drive system (1) for a motor-assisted bicycle (2). claim 1 characterized in that the crank (3) is arranged on the shaft (4) projecting axially out of the first electrical machine (5). Drive system (1) for a motor-assisted bicycle (2) according to one of the preceding claims, characterized in that two cranks (3) are provided, which are each arranged on either side of the shaft (4). Drive system (1) for a motor-assisted bicycle (2) according to one of the preceding claims, characterized in that the adapter sleeve (14) has a 10-tooth profile on the outside, in particular an ISIS profile. Drive system (1) for a motor-assisted bicycle (2) according to one of the preceding claims, characterized in that the crank (3) has an opening which positively surrounds the adapter sleeve (14) at least in sections. Drive system (1) for a motor-assisted bicycle (2) according to one of the preceding claims, characterized in that the first electric machine (5) has a planetary gear (15) which is connected to the crank (3) on the input side and to the generator on the output side. Rotor (6) is coupled. Drive system (1) for a motorized bicycle (2) according to one of the preceding claims, characterized in that the crank connection (13) of the shaft (4) is conical and the adapter sleeve (14) is correspondingly conical on the inside.

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