DE102021129782A1 - Electric drive system and pedal unit that can be operated as a generator - Google Patents

Abstract

The invention relates to an electric drive system (1) for a vehicle (100) that can be operated with muscle power, comprising a first electric machine (2) that can be operated at least as a motor and which, for the purpose of driving, is connected to a drive wheel (101) of the vehicle (100). a second electrical machine (3) that can be operated at least as a generator and has a rotor (6), which is set up to convert mechanical energy introduced by a driver of the vehicle (100) via a pedal-operated actuating device (15) into electrical energy, an energy storage device (4) for storing and delivering electrical energy, and a central control unit (5) for controlling the first electrical machine (3) and for controlling the second electrical machine (2) in such a way that a rotation of the actuating device (15 ) an electrically induced rotation of the drive wheel (101) can be generated, with the rotor (6) of the second electrical machine (3) being coupled to an eccentric gear (7), the eccentric gear (7) being sectionally mounted in an internally toothed ring gear (8). meshing externally toothed eccentric wheel (9), the axis of rotation of which runs eccentrically to the axis of rotation of the ring gear (8).

Description

The present invention relates to an electrical drive system for a vehicle that can be operated with muscle power, comprising a first electrical machine that can be operated at least as a motor, which acts on a drive wheel of the vehicle for the purpose of driving, a second electrical machine that can be operated at least as a generator and has a rotor , which is set up to convert mechanical energy introduced by a driver of the vehicle via a pedal-operated actuating device into electrical energy, an energy storage device for storing and delivering electrical energy, and a central control unit for activating the first electric machine and for activating the second electric machine in such that an electrically induced rotation of the drive wheel can be generated by a muscle-powered rotation of the actuating device. The invention also relates to a pedaling unit that can be operated as a generator.

In addition to conventional motor vehicles, especially passenger cars, society is increasingly focusing on small vehicles in order to meet changing mobility requirements in a future-proof manner. The small vehicles have the advantage that they take up less space than a parking space. On the other hand, the smallest vehicles can be designed in such a way that they can move significantly in city traffic, so that the requirements for possible maximum speeds are very low.

Traditionally, this group of small vehicles also includes, for example, bicycles, which were and are usually operated with muscle power. In addition to the human-powered bicycles, bicycles with auxiliary motors were also developed. With the development of powerful batteries, the auxiliary motors were implemented as environmentally friendly electric motors. Such electric bicycles have now become an integral part of the street scene. These muscle-assisted or pedal-assisted vehicles are known in particular under the names pedelec (pedal electric cycle), e-bike or electric bicycle.

From the DE 10 2013 012 208 A1 such an electrical drive system for a vehicle operated with muscle power is already known, the electrical drive system having at least one electrical generator mechanically connected to a drive crank, an electrical drive motor, an electrical energy store and an electrical circuit arrangement for electrically coupling the generator to the drive motor and the energy store includes.

There are also various concepts for dispensing with the endless traction means, which are subject to mechanical wear, for transmitting muscle power in electrified drive trains. These concepts are also known under the name chainless drive (CLD), in which, for example, a bicycle chain is completely dispensed with.

In conventional chainless drive (CLD) systems, the generator, which is driven by the cranks by the driver, uses electronics to generate a direct current, which can be used to charge a battery and/or drive a drive motor with controllable/adjustable current, independent of the generator speed. Since there is no longer a direct mechanical connection between the driver and the driven wheel with a chainless drive, the driving experience of a mechanical drive train must be electronically simulated by the chainless drive system.

For this purpose, a torque or speed value is usually calculated by a control unit and control software of the chainless drive system on the basis of input parameters from the CLD bottom bracket module, such as angle of rotation, speed, torque, acceleration signals, etc converted into vehicle propulsion.

It is also known in principle that the generator driven by the cranks can be coupled to a gear in order to translate the comparatively low number of revolutions of the cranks when pedaling manually to a higher number of revolutions of the generator rotor. In this context, eccentric gears are also known which allow a comparatively high translation.

Eccentric gears of this type, often also referred to as cycloidal gears, are known in many variants from the prior art. When rotating the gearbox, unwanted noises can occur due to the alternating engagement of the planetary sleeves in the engagement bores of the eccentric gears, which can be uncomfortable when driving. One reason for this is component tolerances and elasticity, due to which the planetary sleeve cannot be guaranteed to rest continuously in the engagement bores over the full revolution. Thus, there is a temporary loss of contact in situations in which no force is transmitted from the planetary sleeves to an eccentric wheel and metallic contact when touching again, from which point force is transmitted. These periodically occurring interventions/cont files produce the annoying noises mentioned.

It is therefore the object of the invention to provide an electric drive system for a vehicle that can be operated with muscle power, which avoids or at least reduces the problems known from the prior art and allows particularly low-noise operation.

This object is achieved by an electrical drive system for a vehicle that can be operated with muscle power, comprising a first electrical machine that can be operated at least as a motor, which acts on a drive wheel of the vehicle for the purpose of driving, a second electrical machine that can be operated at least as a generator and has a Rotor, which is set up to convert mechanical energy introduced by a driver of the vehicle via a pedal-operated actuating device into electrical energy, an energy storage device for storing and delivering electrical energy, and a central control unit for actuating the first electrical machine and for actuating the second electrical machine in such a way that an electrically induced rotation of the drive wheel can be generated by a muscle-powered rotation of the actuating device, the rotor of the second electrical machine being coupled to an eccentric gear, the eccentric gear having an externally toothed eccentric wheel which meshes in sections with an internally toothed ring gear and whose axis of rotation is eccentric to the axis of rotation of the ring gear, with the eccentric wheel having a plurality of circular contact openings, in each of which a planetary sleeve rests, which is rotatably mounted relative to a planetary axis, and the planetary axes are fixed to one another via a planetary carrier, with a plurality of the planetary sleeves each having a circumferential damping element, each is partially in contact with one of the contact openings of the eccentric wheel and/or a plurality of the contact openings each have a circumferential damping element, which is partially in contact with one of the planet sleeves.

According to the invention, it is therefore proposed that play caused by component tolerances, thermal expansion or elastic deformations or the temporary (complete) loss of contact be prevented and/or the renewed contact "impact" should be dampened by having a particularly elastic damping element per planetary sleeve/eccentric wheel contact .

The vehicle is preferably designed as a small or very small vehicle or as an electric vehicle. The vehicle is preferably multi-track, e.g. designed with three or more wheels. Alternatively, the vehicle can be designed as a bicycle, in particular as an electric bicycle, e.g. as a pedelec or as an e-bike. For example, the vehicle can be a transport or cargo bike, in particular a motorized or electrically driven transport or cargo bike, in particular a three-wheel or four-wheel pedelec or a rickshaw, in particular with or without a roof, or a cabin scooter.

In principle, it would of course also be conceivable for a plurality of electrical machines that can be operated as motors to be coupled to a machine that can be operated as a generator. In this way, for example, a multi-axle drive concept or all-wheel drive could be implemented in a multi-lane vehicle. It would also be possible for several machines that can be operated as a generator to be coupled with one machine that can be operated electrically, so that tandem drive concepts, for example, in which, for example, two people feed muscle power into the drive system, can be implemented. Finally, it is also possible to further develop the drive concept by coupling a plurality of electrical machines that can be operated as generators with a plurality of electrical machines that can be operated as motors.

According to an advantageous embodiment of the invention, it can be provided that the planet sleeves each have a circumferential groove into which the damping element is inserted and axially fixed and/or the contact openings each have a circumferential groove into which the damping element is inserted and axially fixed.

According to a further preferred further development of the invention, it can also be provided that the damping element is formed from an elastic material, in particular from a rubber.

Furthermore, according to a likewise advantageous embodiment of the invention, it can be provided that the damping element is an O-ring.

A possible embodiment variant thus includes one O-ring per contact point, which is inserted, for example, in grooves in the planetary sleeves in such a way that its outer diameter protrudes slightly beyond the outer diameter of the planetary sleeve. In this way, the otherwise occurring play between the planetary sleeve and the contact opening is bridged by the slightly protruding O-ring and the metallic “impact” on renewed contact is dampened by (slight) elastic deformation of the damping element. Instead of an O-ring made of rubber, elastic rings made of e.g Plastic or metal can be used, which produce a resilient/damping effect due to their geometry. It goes without saying that the damping elements can alternatively also be used in grooves which are made in the contact openings (inner diameter) instead of in the planet sleeves (outer diameter).

According to a further particularly preferred embodiment of the invention, it can be provided that the axial extent of the contact surface between one of the damping elements and the corresponding contact opening is between 1-30% of the axial extent of the contact opening. Furthermore, the invention can also be further developed in this context to the effect that the contact surface runs approximately axially in the center of the axial extent of the contact opening. The damping elements thus extend in the axial direction preferably only over a short section, preferably in the (axial) center of the contact opening, in order to ensure symmetrical power transmission and to be able to provide as much axial width as possible for power transmission.

In a likewise preferred embodiment variant of the invention, it can also be provided that at least one of the damping elements is designed as a coating. As an alternative to separate components for contact damping, coatings made of plastic or rubber with a corresponding radial thickness are also conceivable. For this purpose, the counter-contact surface or directly the coated diameter can be removed accordingly, so that only a small part of the coated volume protrudes beyond the force-transmitting contact diameter in order not to "crush" the coating but only to elastically displace it.

The object of the invention is also achieved by a pedaling unit that can be operated as a generator for an electric drive system of a vehicle that can be operated with muscle power, comprising an electrical machine that can be operated at least as a generator and has a rotor, which is set up for mechanical energy to be introduced by a driver of the vehicle via a pedalable actuating device into electrical energy, the rotor of the second electrical machine being coupled to an eccentric gear, the eccentric gear having an externally toothed eccentric wheel which meshes in sections with an internally toothed ring gear, the axis of rotation of which runs eccentrically to the axis of rotation of the ring gear, the eccentric wheel having a plurality of circular contact openings , in each of which rests a planetary sleeve that is rotatably mounted relative to a planetary axis and the planetary axes are fixed to one another via a planetary carrier, with a plurality of the planetary sleeves each having a circumferential damping element that is in contact with one of the contact openings of the eccentric wheel in sections and/or a plurality each of the contact openings has a circumferential damping element which is in contact with one of the planet sleeves in sections.

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

• 1 eine schematische Darstellung eines elektrischen Antriebssystems,
• 2 eine schematische Axialschnittansicht einer generatorisch betreibbaren Pedalliereinheit,
• 3 eine Frontalansicht auf ein Exzentergetriebe der generatorisch betreibbaren Pedalliereinheit.

It shows:

• 1 a schematic representation of an electric drive system,
• 2 a schematic axial section view of a pedaling unit that can be operated as a generator,
• 3 a front view of an eccentric gear of the pedaling unit that can be operated as a generator.

The 1 shows an electrical drive system 1 for a vehicle 100 that can be operated with muscle power, comprising a first electrical machine 2 that can be operated at least as a motor, which acts on a drive wheel 101 of the vehicle 100 for the purpose of driving, and a second electrical machine that can be operated at least as a generator 3 with a rotor 6, which is set up to convert mechanical energy introduced by a driver of the vehicle 100 via a pedal-operated actuating device 15 into electrical energy.

This manually generated electrical energy is fed to an energy storage device 4 for storing and delivering electrical energy and stored there. The electrical machine 2 that can be operated as a motor then draws its electrical energy from this energy storage device 4.

Of course, it is also conceivable that the electrical machine 3 that can be operated as a generator can be electrically connected directly to the electrical machine 2 that can be operated as a motor. The electrical machine 3, which can be operated as a generator, can also be fed from the energy storage device 4 in order, for example, to achieve a natural pedaling feeling for the driver by generating a resistance torque.

A central control unit 5 for controlling the first electric machine 3 and for controlling the second electric machine 2 is provided for controlling the drive system 1, see above that an electrically induced rotation of the drive wheel 101 can be generated by a muscle-powered rotation of the actuating device 15 . As a result, a mechanical power transmission between the actuating device 15 and the drive wheel 101, for example in the form of a chain, can be dispensed with.

As emerges from the 2 can be seen, the rotor 6 of the second electric machine 3 is coupled to an eccentric gear 7 . The eccentric gear 7 has an externally toothed eccentric wheel 9 meshing in sections with an internally toothed ring gear 8 , the axis of rotation of which runs eccentrically to the axis of rotation of the ring gear 8 . The eccentric wheel 9 has a plurality of circular contact openings 10, in each of which rests a planetary sleeve 12 that is rotatably mounted relative to a planetary axis 11. The planetary axes 11 are fixed to one another via a planetary carrier 13 .

The planet sleeves 12 each have a circumferential damping element 14, which is in sections in contact with one of the contact openings 10 of the eccentric wheel 9, which is also good from the synopsis of 2-3 is recognizable. To accommodate a damping element 14 designed as an O-ring, the planetary sleeves 12 each have a circumferential groove 16 into which the O-ring 14 is inserted and axially fixed.

Alternatively or additionally, it is also possible that the contact openings 10 each have a circumferential damping element 14, which is in contact with one of the planetary sleeves 12 in sections, and that the contact openings 10 each have a circumferential groove 16 into which the damping element 14 is inserted and axially fixed is.

In the exemplary embodiment shown, the damping element 14 is formed from an elastic material, in particular from rubber. In the in the 2 shown embodiment of the invention, the eccentric gear 7 has two eccentric wheels 9, the eccentricities are offset by 180 ° to each other. The two eccentric wheels 9 are acted upon by a common planetary sleeve 12 on the respective contact surfaces 17 of the contact openings 10 in the circumferential direction. All contact surfaces 18 between the eccentric gears 9 and the planetary sleeve 12 have a damping element 14 . In principle, it would of course also be conceivable to design the planetary sleeve 12 in two parts, in which case each half of the planetary sleeve is then assigned to one of the two eccentric wheels 9 .

One recognizes in particular from the representation of 2 it is good that the axial extent of the contact surface 17 between one of the damping elements 14 and the corresponding contact opening 10 is between 1-30% of the axial extent of the contact opening 10 . The contact surface 17 runs approximately axially in the center of the axial extent of the contact opening 10.

When a user pedals, the drive shaft 21 is actuated or rotated. The drive shaft 21 is non-rotatably connected to the planet carrier 13 . The planetary axles 11 are fixed in the planetary carrier 18 and run correspondingly around the axis of rotation of the drive shaft 21 with the planetary carrier 13 . The planetary sleeves 12 are rotatably mounted on the planetary carrier 13 via the planetary bearings 22 , which sleeves engage in the contact openings 10 of the eccentric gears 9 . The eccentric wheels 9 complete the same number of revolutions as the drive shaft 21. Due to the eccentricity of the eccentric wheels 9 to the ring gear 9, these are only partially engaged, which is also good from the 3 is recognizable.

The rotor 6 is connected to the eccentric gear 7 via a rotor shaft 23 . For this purpose, the rotor shaft 23 has two eccentric sections 24 formed monolithically with this, which protrude axially out of the electrical machine 3 in the direction of the eccentric gear 7 and engage axially in the eccentric gear 7 . The eccentric sections 24 each have an eccentric bearing 26 for the eccentric wheels 9 on their radially outer lateral surfaces 25. The section of the rotor shaft 23 running in the stator 20 is arranged coaxially thereto.

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. If the patent claims and the above description define 'first' and 'second' feature, this designation serves to distinguish between two similar features without establishing a ranking.

Reference List

1

drive system

2

first electric machine (motor)

3

second electrical machine (generator)

4

energy storage device

5

control unit

6

rotor

7

eccentric gear

8th

ring gear

9

eccentric wheel

10

contact opening

11

planet axis

12

planet sleeve

13

planet carrier

14

damping element

15

actuating device

16

groove

17

contact surface

18

Housing

19

tangential force vector

20

stator

21

drive shaft

22

planetary bearings

23

rotor shaft

24

eccentric sections

25

lateral surface

26

storage

100

vehicle

101

drive wheel

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 102013012208 A1 [0004]

Claims (8)

Electrical drive system (1) for a vehicle (100) that can be operated with muscle power, comprising • a first electrical machine (2) that can be operated at least as a motor and acts on a drive wheel (101) of the vehicle (100) for the purpose of driving, • a second electrical machine (3) that can be operated at least as a generator and has a rotor (6), which is set up to convert mechanical energy introduced by a driver of the vehicle (100) via a pedal-operated actuating device (15) into electrical energy, • an energy storage device ( 4) for storing and delivering electrical energy, and • a central control unit (5) for controlling the first electric machine (3) and for controlling the second electric machine (2) in such a way that a rotation of the actuating device (15 ) an electrically caused rotation of the drive wheel (101) can be generated, characterized in that the rotor (6) of the second electrical machine (3) is coupled to an eccentric gear (7), the eccentric gear (7) having an internally toothed ring gear ( 8) has externally toothed eccentric wheel (9) that meshes in sections, the axis of rotation of which runs eccentrically to the axis of rotation of the ring gear (8), the eccentric wheel (9) having a plurality of circular contact openings (10), in each of which one can be rotated relative to a planetary axis (11). mounted planetary sleeve (12) and the planetary axes (11) are fixed to one another via a planetary carrier (13), with a plurality of planetary sleeves (12) each having a circumferential damping element (14) which is partially in contact with one of the contact openings (10th ) of the eccentric wheel (9) and/or a plurality of the contact openings (10) each have a circumferential damping element (14) which is in contact with one of the planet sleeves (12) in sections. Electric drive system (1) according to claim 1 , characterized in that the planet sleeves (12) each have a circumferential groove (16) into which the damping element (14) is inserted and fixed axially and/or the contact openings (10) each have a circumferential groove (16) into which the damping element (14) is inserted and fixed axially. Electrical drive system (1) according to one of the preceding claims, characterized in that the damping element (14) is formed from an elastic material, in particular from a rubber. Electrical drive system (1) according to one of the preceding claims, characterized in that the damping element (14) is an O-ring. Electrical drive system (1) according to one of the preceding claims, characterized in that the axial extent of the contact surface (17) between one of the damping elements (14) and the corresponding contact opening (10) is between 1-30% of the axial extent of the contact opening (10) amounts to. Electrical drive system (1) according to one of the preceding claims, characterized in that the contact surface (17) runs approximately axially centrally to the axial extent of the contact opening (10). Electrical drive system (1) according to one of the preceding claims, characterized in that at least one of the damping elements (14) is designed as a coating. Pedal unit that can be operated as a generator for an electric drive system (1) of a vehicle (100) that can be operated with muscle power, comprising an electric machine (3) that can be operated at least as a generator and has a rotor (6), which is set up by a driver of the vehicle (100) via a pedalable actuating device (15) to convert mechanical energy into electrical energy, characterized in that the rotor (6) of the second electrical machine (3) is coupled to an eccentric gear (7), the eccentric gear (7) having an internally toothed ring gear (8) has externally toothed eccentric wheel (9) that meshes in sections, the axis of rotation of which runs eccentrically to the axis of rotation of the ring gear (8), the eccentric wheel (9) having a plurality of circular contact openings (10), into each of which one opposite a planetary axis (11) rotatably mounted planetary sleeve (12) and the planetary axes (11) are fixed to one another via a planetary carrier (13), with a plurality of planetary sleeves (12) each having a circumferential damping element (14) which is partially in contact with one of the contact openings ( 10) of the eccentric wheel (9) and/or a plurality of the contact openings (10) each have a circumferential damping element (14) which is in contact with one of the planet sleeves (12) in sections.

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