WO2011069722A1

WO2011069722A1 - Drive device for a bicycle

Info

Publication number: WO2011069722A1
Application number: PCT/EP2010/065420
Authority: WO
Inventors: Jochen Moench; Hans-Peter Dommsch; Philipp Kohlrausch
Original assignee: Robert Bosch Gmbh
Priority date: 2009-12-10
Filing date: 2010-10-14
Publication date: 2011-06-16
Also published as: DE102009054480A1

Abstract

The invention relates to a drive device (1, 30) for a bicycle, comprising: a motor (2, 32) for generating a first mechanical driving power, - a pedal crank (3, 33), a chain ring (4, 34) and a superimposed gear, characterized in that the superimposed gear is a planetary gear comprising a sun (5, 35), a planet wheel (12, 42a, 42b) mounted by means of a planet carrier (7, 37), and a ring gear (6, 36), wherein the chain ring (4, 34) is connected to the planet carrier (87, 37) and the motor (2, 32) is coupled to the ring gear (6, 36) and the pedal crank (3, 33) is coupled to the sun (5, 35), or vice versa, for summing the first mechanical driving power by means of a second mechanical driving power generated by means of the pedal crank (3, 33). The invention further relates to a bicycle comprising a drive device (1, 30).

Description

description

title

Drive device for a bicycle

The invention relates to a drive device for a bicycle and a bicycle with such a drive device.

State of the art

In order to assist a cyclist when pedaling, especially on a slope or in strong headwind, usually an electric drive, in particular electric auxiliary motors is used. Bicycles with auxiliary electric motors are also commonly referred to as Pedalec. Here, the auxiliary motor either drives the chain in addition to the chainring, for example, the so-called Panasonic drive, the bottom bracket, for example, the so-called Gruber Assist drive, the chainring, for example, the so-called Opti-Bike LLC drive, or the rear wheel to either directly by means of a hub drive, by means of a toothed belt or a chain.

In the aforementioned drives is intervened directly in the chain drive or the rear wheel, that is, that the rear wheel or chain speed is rigidly linked to the electric drive. Therefore, a power of the electric drive is directly coupled to the cadence or cadence predetermined by a rolling speed of the wheel or the driver. The disadvantage of this, however, is that the driver is supported only to the extent that the driver himself generates a mechanical drive power. That is, if the driver generates a high mechanical drive power, then he is supported by the electric drive more than if he produces only a small mechanical drive power. Especially with long climbs, the driver will be able to produce only a small drive power, whereby he is then supported by the electric drive only slightly. Furthermore, the aforementioned drives do not allow a particularly compact and integrated design, since the auxiliary motor is usually mounted on the bike. However, this increases an air resistance, which makes it even more difficult for the driver to generate a mechanical drive power. In this respect, it would be desirable to integrate the electric auxiliary motor with the drive elements already present on the bicycle.

Disclosure of the invention

It is therefore an object of the invention to provide a driving device for a bicycle and a bicycle, which overcomes the above disadvantages and enables a compact design and a support of the driver by means of an electric assist motor regardless of a mechanical drive power generated by the driver.

The object is achieved by the drive device according to claim 1 and by the bicycle according to claim 6. Preferred embodiments of the invention are the subject of dependent subclaims.

The invention includes the idea of coupling a mechanical drive power generated by the driver with the mechanical drive power generated by the motor by means of a planetary gear, in particular a 3-shaft planetary gear, so that the two drive powers are added up. The planetary gear is a compact-built gear transmission, which generally has three coaxially arranged shafts, each with a gear. The inner gear is also called the sun gear or the sun, the outer gear is referred to as a ring gear, which preferably has an outer toothing, and arranged between the sun and ring gear third gear is the planetary gear, which is on a planet carrier, also called web, stored , In particular, the planet gear is mounted by means of a planetary pin on the web. As a rule, a plurality of planet gears are provided, preferably two planet gears, in particular three planet gears.

The chainring according to the invention is connected to the planet carrier or web, so that the chainring rotates when the web rotates, which in particular will be the case when the planetary gear or wheels rotate. WEI terhin are according to the invention either the pedal with the sun and the engine with the ring gear or the crank with the ring gear and the engine coupled to the sun. By means of this coupling, the crank and the engine drive the ring gear and the sun. As a result, then drive the ring gear and the sun on the planet or the planetary gears, so that also rotate the web and connected to the bridge chainring. The chainring can then drive, for example by means of a chain pinion of a rear wheel.

Due to the coupling according to the invention by means of a planetary gear an extremely compact and integrated construction is possible. As a result, air resistance of the bicycle is significantly reduced, the bicycle has so far a particularly streamlined and sporty shape.

Furthermore, due to the compact structure results in a very favorable center of gravity of the bicycle, so that the bicycle has a safe road holding and tipping over of the bicycle, especially in dangerous situations such as during emergency braking with simultaneous evasion, is significantly reduced.

Furthermore, the invention allows advantageously to use motors with much smaller work areas or fields of work as drive motors, since according to the invention the drive power generated by the engine is no longer linked rigidly with a rear wheel or chain speed.

In another preferred embodiment of the invention, a freewheel device is provided. For example, the engine may include a freewheel device. But it can also be provided in particular that the planetary gear comprises a freewheel device. This means that the motor-driven element of the planetary gear, so either the sun or the ring gear, has a freewheel device. Preferably, both the motor and the driven element each comprise a freewheel device. This advantageously prevents the engine from turning back in the event of a motor failure, for example due to an empty battery. In another embodiment according to the invention, the planetary gear comprises a displaceable connecting element for mechanical connection of the web or the planet carrier with the crank. The driver can shift the connecting element from a normal position, in which the pedal crank drives the sun or the ring gear, into a blocking position, in which the web is directly mechanically connected to the pedal crank. In the locked position, the driver drives the chainring directly. The planetary gear is locked, the connecting element is insofar a mechanical lock. This embodiment offers the advantage that the driver does not have to use a reduction or translation of the planetary gear when the engine no longer generates mechanical drive power because it has failed or because it has been switched off by the driver.

In a further embodiment according to the invention, preferably both a displaceable connecting element and a freewheel device can be provided. By the combination of freewheel and mechanical lock can be advantageously prevented that the driver enters the "void" when the engine is switched off or fails, and further allows the driver by means of the connecting element can switch at least two gears.

In an exemplary embodiment of the invention, the motor has at least one motor pinion. The motor pinion can engage in particular directly in the teeth of the sun or in an external toothing of the ring gear, so that a direct and efficient coupling between the motor and the planetary gear is possible.

In an exemplary embodiment, a bicycle according to the invention may comprise an electric gearshift which is connected to a control device coupled to the engine for regulating the first mechanical drive power. As a result, a support of a switching operation can be achieved in an advantageous manner.

The invention will be explained in more detail below with reference to preferred embodiments with reference to figures of a drawing. Show here

1 is a schematic representation of a drive device, Fig. 2 is a construction drawing of the drive apparatus shown in Fig. 1, Fig. 3 is a schematic view of another drive apparatus, and Fig. 4 is a construction drawing of the drive apparatus shown in Fig. 3. figure description

Fig. 1 shows a schematic representation of a drive device 1 for a bicycle. The drive device 1 comprises a motor 2. In the embodiment shown here, the motor 2 is an electric motor. In particular, the electric motor has a stator and a rotor arranged in the stator. The rotor has a coil with an iron core, which is also referred to as anchor on. In an exemplary embodiment of the invention, the electric motor comprises an accumulator, a fuel cell or a battery. For example, the electric motor may also include solar cells that charge the accumulator or the fuel cell or directly supply the electric motor with power. As a result, the type of electric current required for the electric motor is generated in a particularly environmentally friendly manner, since no C0 ₂ or unhealthily harmful exhaust gases are emitted.

In an embodiment not shown, it may also be provided that the engine 2 is, for example, a gasoline engine or a diesel engine. In particular, it can be provided that the engine 2 is a hybrid engine.

The drive device 1 further comprises a pedal crank 3, which is connected to a bottom bracket 8. The bottom bracket 8 is arranged in a housing 9. By means of this arrangement, the bottom bracket 8 is protected in an advantageous manner from dirt and moisture. Preferably, the housing is integrated in a bicycle frame. The bottom bracket 8 further includes a freewheel device 10. Furthermore, the drive device 1 comprises a chainring 4, which by means of a chain (not shown) can drive a rear wheel of a bicycle. In a further embodiment, not shown, the chainring 4 can also drive the rear wheel by means of a belt. The pedal crank 3, the motor 2 and the chainring 4 are coupled together by means of a planetary gear as follows. The pedal crank 3 is coupled to a sun 5 of the planetary gear, so that a driver when pedaling the sun 5 drives. The motor 2 is coupled by means of a motor pinion 1 1 with a ring gear 6 of the planetary gear. For this purpose, the ring gear 6 on an outer toothing, which engage in the motor pinion 1 1 (see Fig. 2). The chainring 4 is connected to a web ball bearing 15 having web 7, which supports a planet gear 12 (see FIG. 2). A generated by the motor 2 first mechanical drive power will drive the ring gear 6 of the planetary gear. A second mechanical drive power, which is generated by means of the crank, drives the sun 5 of the planetary gear. These two mechanical drive powers are transmitted to the planet gear 12 of the planetary gear. Since the chainring 4 is connected to the web 7, when the planet gear 12 and thus the web 7 rotate, and the chainring 4 rotate. The two mechanical drive powers are so far summed by means of the planetary gear on the chainring 4.

The motor pinion can alternatively intervene directly in the teeth of the sun. For example, it can also be provided that the motor pinion is coupled by means of a positive toothed belt with the teeth of the sun or the external toothing of the ring gear. Also, a belt transmission or a spur gear can couple the engine with the sun or the ring gear.

Fig. 2 shows a construction drawing of the drive device 1 shown schematically in Fig. 1. In addition to the elements already shown in Fig. 1, Fig. 2 shows the planetary gear 12, which has a planetary ball bearing 13. The planet gear 12 is mounted by means of a planetary pin 14 on the planet carrier or the web 7. At the planet pin 14, the chainring 4 is arranged. In the embodiment shown in Fig. 2, the bottom bracket 8 forms the shaft of the sun 5. This has the particular advantage that on the one hand so a direct and efficient coupling of the drive power generated by the driver is achieved with the sun. On the other hand, the construction achieved with it is particularly compact.

Fig. 3 shows a schematic representation of a further drive device 30, which is shown in more detail in Fig. 4 with reference to a construction drawing. The drive device 30 comprises a motor 32 with a plurality of engine pinions 41. Furthermore, the drive device 30 comprises a pedal crank 33, which is connected to a bottom bracket 38. The bottom bracket 38 has a freewheel device 40. Further, a housing 39 is provided, in which the bottom bracket 38 is arranged. In contrast to the embodiment shown in FIGS. 1 and 2, in the embodiment shown in FIG. 3, the pedal crank 33 is coupled to a ring gear 36 of a planetary gear and the motor 32 to a sun 35. The coupling between the motor 32 and the sun 35 takes place in that the motor pinion 41 of the motor 32 interact with an external toothing of the sun 35. The respective teeth interlock in this respect. Further, a chainring 34 is connected to a web 37 of the planetary gear on the planetary gear. In this exemplary embodiment, the web supports two planetary gears 42a and 42b (see FIG. 4) by means of a common planetary bolt 44. Both planetary gears 42a and 42b have a planetary ball bearing 43. The teeth of the planetary gear 42a engage with the teeth of the sun 35 and the teeth of the planetary gear 42b engage in the internal teeth of the ring gear 36. When the motor 32 drives the sun 35 and the crank 33 drives the ring gear 36, both planetary gears 42a and 42b rotate, and thus also the land 37, so that the drive power generated by the engine adds up with the drive power generated by the driver and the accumulated drive power is transmitted to the chainring 34. The chainring 34 can then drive a rear wheel of a bicycle by means of a chain (not shown).

The embodiment shown in FIGS. 3 and 4 with the two planet wheels 42a and 42b has the particular advantage that a reduction range of the planetary gear can be expanded, in particular when planets are used which are graduated from one another.

Although not explicitly shown here, the motor 2, 32 can not only be arranged axially parallel to the bottom bracket 8, 38 in the embodiments shown here. In particular, such an arrangement has the advantage of achieving an optimum arrangement of the motor on the bicycle with respect to a ground clearance, a position of the front / rear wheel and the center of gravity of the bicycle.

In a further embodiment, not shown, the motor 2, 32 are arranged concentrically around the bottom bracket 8, 38, in which case one or several planetary gear stages for a particularly advantageous reduction of an armature speed of the motor 2, 32 may be provided.

A bicycle according to the invention may comprise an electric gearshift which is connected to a control device (not shown) coupled to the engine 2 for controlling the first mechanical drive power. In this way, a support of a switching operation is advantageously made possible by the fact that the control device reduces the first mechanical drive power shortly before the switching operation. After the switching operation, the control device increases the first mechanical drive power again. In particular, in a chain and hub circuit thereby the switching process is particularly supported. In a derailleur, the control device can increase the first mechanical drive power shortly before the shift and reduce again after the shift, so that a brief rotation of the chain center of the derailleur takes place. The control device further advantageously allows the drive power generated by the engine to not drop abruptly to zero when the driver turns off the engine. Here, the control means continuously controls the drive power down to zero, so that reverse rotation of the drive in the case of abrupt shutdown of the engine, which reverse rotation adversely absorbs the drive power generated by the driver, is prevented, so the driver does not step into the void, especially if none Freewheel device is provided.

The bicycle may have various transmission stages listed below:

- Manual transmission, such as a hub gear or a derailleur

- Reduction in the chain drive between pinion in the rear wheel and in the chainring

- Stand reduction of the planetary gear

- Reduction of the motor, in particular an electric motor, between the armature and the sun or between the armature and ring gear.

Claims

claims

1 . Driving device (1, 30) for a bicycle, comprising:

a motor (2, 32) for generating a first mechanical drive power,

a pedal crank (3, 33),

a chainring (4, 34), and

a superposition gearbox,

characterized,

in that the superposition gearing comprises a planetary gearing with a sun (5,

35), one by means of a planet carrier (7, 37) mounted planet gear (12, 42 a, 42 b) and a ring gear (6, 36), wherein the chainring (4, 34) with the planet carrier (7, 37) is connected and the motor (2, 32) with the ring gear (6, 36) and the pedal crank (3, 33) with the sun (5, 35) or vice versa are coupled to sum up the first mechanical drive power by means of the pedal crank (3 , 33) generated second mechanical drive power.

2. Drive device (1, 30) according to claim 1, characterized in that the planetary gear and / or the motor (2, 32) comprises a freewheel device.

3. Drive device (1, 30) according to claim 1 or 2, characterized in that the planetary gear a displaceable connecting element for mechanically connecting the pedal crank (3, 33) with the planet carrier

(7, 37).

4. Drive device (1, 30) according to one of the preceding claims, characterized in that the motor (2, 32) has at least one motor pinion (1 1, 41), which with the sun (5, 35) or the ring gear (6 , 36) is coupled.

5. Drive device (1, 30) according to claim 4, characterized in that the at least one motor pinion (1 1, 41) by means of a positive toothed belt with the sun (5, 35) or the ring gear (6, 36) is coupled.

6. bicycle with a drive device (1, 30) according to one of the preceding claims.

7. Bicycle according to claim 6, characterized in that the motor (2, 32) has a control device for controlling the first mechanical drive power.

8. Bicycle according to claim 7, characterized by an electrical gearshift device, which is connected to the control device.