CN117529433A - Drive unit for electric bicycle - Google Patents
Drive unit for electric bicycle Download PDFInfo
- Publication number
- CN117529433A CN117529433A CN202280033399.6A CN202280033399A CN117529433A CN 117529433 A CN117529433 A CN 117529433A CN 202280033399 A CN202280033399 A CN 202280033399A CN 117529433 A CN117529433 A CN 117529433A
- Authority
- CN
- China
- Prior art keywords
- shaft
- drive
- drive unit
- transmission
- driven shaft
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 230000005540 biological transmission Effects 0.000 claims abstract description 43
- 210000003205 muscle Anatomy 0.000 claims abstract description 7
- 230000008878 coupling Effects 0.000 description 4
- 238000010168 coupling process Methods 0.000 description 4
- 238000005859 coupling reaction Methods 0.000 description 4
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000010276 construction Methods 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62M—RIDER PROPULSION OF WHEELED VEHICLES OR SLEDGES; POWERED PROPULSION OF SLEDGES OR SINGLE-TRACK CYCLES; TRANSMISSIONS SPECIALLY ADAPTED FOR SUCH VEHICLES
- B62M6/00—Rider propulsion of wheeled vehicles with additional source of power, e.g. combustion engine or electric motor
- B62M6/40—Rider propelled cycles with auxiliary electric motor
- B62M6/55—Rider propelled cycles with auxiliary electric motor power-driven at crank shafts parts
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62M—RIDER PROPULSION OF WHEELED VEHICLES OR SLEDGES; POWERED PROPULSION OF SLEDGES OR SINGLE-TRACK CYCLES; TRANSMISSIONS SPECIALLY ADAPTED FOR SUCH VEHICLES
- B62M11/00—Transmissions characterised by the use of interengaging toothed wheels or frictionally-engaging wheels
- B62M11/04—Transmissions characterised by the use of interengaging toothed wheels or frictionally-engaging wheels of changeable ratio
- B62M11/14—Transmissions characterised by the use of interengaging toothed wheels or frictionally-engaging wheels of changeable ratio with planetary gears
- B62M11/145—Transmissions characterised by the use of interengaging toothed wheels or frictionally-engaging wheels of changeable ratio with planetary gears built in, or adjacent to, the bottom bracket
Abstract
The proposed solution relates to a drive unit (a) for an electric bicycle, having: at least one driven shaft (2); a drive shaft (1) rotatable about a drive rotation axis (D1) for generating a first drive torque by muscle force manipulation by a rider of the electric bicycle; an electric motor (E) for generating a second drive torque by external power steering on a rotor shaft (3) coupled to the electric motor (E); and a transmission (4, 5) having at least one planetary gear (5) for transmitting the first and second drive torques to the driven shaft (2). In the proposed drive unit (A), the rotor shaft (3) and the driven shaft (2) are arranged coaxially to each other, and the drive rotation axis (D1) extends parallel to the rotor shaft (3) and the driven shaft (2).
Description
Technical Field
The proposed solution relates to a drive unit for an electric bicycle.
Background
It is known to use at least one electric motor in combination with a transmission having a planetary gear stage on an electric bicycle, i.e. on a so-called electric bicycle (E-Bike) or electric bicycle (pedele), in order to provide motor-type assistance when riding the electric bicycle. The respective drive unit has, on the one hand, a drive shaft (also typically referred to as a bottom bracket), via which a drive torque generated by the rider of the electric bicycle can be introduced and to which a pedal is provided on the drive shaft. In addition to the first drive torque which is introduced into the drive shaft by muscle force actuation, the second drive torque can also be provided by means of an electric motor and thus by external force actuation. The at least one electric motor and the driven shaft are coupled to each other via a transmission of the drive unit, so that the driven shaft to be coupled to the wheels of the electric bicycle via the drive unit can transmit torque from the first and second drive torques to the wheels, typically the rear wheels of the electric bicycle.
In such a drive unit, the drive shaft and the driven shaft are generally arranged coaxially with each other. For example, the drive shaft is then embodied as a hollow shaft for this purpose. However, the drive shaft is relatively heavy. However, this is still acceptable in order to make the construction of the drive unit more compact.
Accordingly, there is still a need for an improved or alternative drive unit, such as a drive unit that can be reduced in weight, in a drive unit for an electric bicycle, in particular for a so-called mid-motor.
Disclosure of Invention
Based on this, the drive unit of claim 1 is proposed.
The proposed drive unit for an electric bicycle comprises at least the following:
a driven shaft for providing a torque for driving the electric bicycle,
a drive shaft rotatable about a drive rotation axis for generating a first drive torque by muscle force manipulation by a rider of the electric bicycle,
an electric motor for a second drive torque generated by external power steering on a rotor shaft coupled to the electric motor, and
a transmission with at least one planetary gear for transmitting the first and second drive torques to the driven shaft.
In the proposed drive unit, the rotor shaft and the driven shaft are arranged coaxially with each other, and the drive rotation axis extends parallel to the rotor shaft and parallel to the driven shaft.
Thus, the driven shaft is coaxial with the rotor shaft of the electric motor and not coaxial with the drive shaft. More precisely, the drive shaft with its drive axis of rotation extends parallel to the common axis of rotation of the rotor shaft and the driven shaft but offset. The proposed solution here comprises, inter alia: within the housing of the drive unit, the drive shaft is arranged parallel to the rotor shaft and to the driven shaft.
As a result of the parallel arrangement of the drive shaft and the driven shaft, a first drive torque which is produced by muscle force actuation can be transmitted from the drive shaft to the driven shaft via at least one gear stage of the transmission. Thus, the drive shaft does not need to be configured as a hollow shaft, and the torque acting on the drive train and its switching mechanism can also be reduced. The drive shaft, which is spatially more separated from the driven shaft, can thus be formed, for example, from a lighter material such as aluminum, which results in a weight saving.
The second drive torque is transmitted via the transmission to the driven shaft, for example from the rotor shaft via a planetary transmission of the transmission. The rotor shaft is then coupled, for example, to a sun gear of the planetary gear, for example, to a sun gear of this type in a rotationally fixed manner.
Alternatively or additionally, the driven shaft may be coupled with a planet carrier of the planetary gear. This also includes, for example, a rotationally fixed connection between the planet carrier of the planetary gear and the output shaft. The ring gear, which is in engagement with the planet elements of the planet carrier (stationary) can be fixed to the housing of the drive unit. The rotational speed of the rotor shaft is slowed down here via the planetary gear.
In order to provide decoupling of the driven shaft from the electric motor in certain driving situations and in particular in certain driving speeds of the electric bicycle, one embodiment variant of the proposed solution is provided with a (rotor-side) one-way clutch via which the rotor shaft is coupled with the rotor of the electric motor. The rotor of the electric motor can thus be decoupled from the rotor shaft via such a one-way clutch, so that the rotor no longer transmits torque to the rotor shaft when the rotational speed exceeds a threshold value. Such rotor-side one-way clutches also include one-way clutches between the components connected in a rotationally fixed manner to the rotor shaft and the rotor of the electric motor.
For transmitting the first drive torque from the drive shaft to the driven shaft, the transmission may comprise at least one gear stage (in particular, irrespective of the planetary transmission), wherein the gear stage is formed, for example, by a spur gear or a belt transmission of the transmission. Here, the belt drive may provide a cost advantage over the spur gear drive. In turn, the spur gear transmission can have advantages in terms of the radial and/or axial installation space required for the respective gear stage. At least one gear stage arranged between the drive shaft and the driven shaft has a positive gear ratio, so that the rotational speed of the drive shaft can be increased and the rotational directions of the drive and driven shafts are in the same direction. It is also advantageous here to speed up in order to reduce the torque to be transmitted of the existing one-way clutch.
For this purpose, a multi-stage transmission, in particular a multi-stage spur gear transmission, can of course also be provided. This includes, for example: the first gearwheel, which is connected to the drive shaft in a rotationally fixed manner, meshes with an intermediate gearwheel, which in turn meshes with a second gearwheel, which is associated with the driven shaft and is a drive element on the driven shaft side. The multi-stage transmission can be provided here just to provide the positive transmission ratio between the drive shaft and the driven shaft and thus the desired co-directional rotational direction.
In one embodiment variant, at least one gear stage arranged between the driven shaft and the drive shaft comprises a rotatable transmission element, which is coupled to the driven shaft via a one-way clutch (on the transmission side). The transmission element which can rotate about the (driven) axis of rotation of the driven shaft is typically a gear or a pulley, for example. The one-way clutch may also be arranged between the transmission component and a component connected to the driven shaft in a rotationally fixed manner. The one-way clutch on the transmission side enables the drive shaft to be decoupled from the driven shaft when the rotational speed exceeds a threshold value, so that the drive shaft, which is actuated by the muscle force of the user, does not rotate together even at high speeds of the driven shaft.
If one implementation variant is to combine two one-way clutches as follows: a rotor-side one-way clutch between the rotor and the rotor shaft of the electric motor and a transmission-side one-way clutch between the transmission stage coupling the drive shaft and the driven shaft makes it possible to achieve a relatively small and advantageous design size of the proposed drive unit. The number of components to be provided for the drive unit for generating and coupling the drive torque can also be kept relatively small.
The proposed solution also comprises an electric bicycle with an implementation variant of the proposed drive unit.
Drawings
The figures exemplarily illustrate possible implementation variants of the proposed solution.
Wherein:
fig. 1 shows a schematic diagram of an embodiment variant of the proposed drive unit with a rotor-side one-way clutch and a transmission-side one-way clutch.
Detailed Description
Fig. 1 shows a schematic diagram of a drive unit a for a center motor of an electric bicycle. The drive unit a includes a housing G mounted on a bicycle frame of the electric bicycle. In particular, an electric motor E having a rotatable rotor R is arranged in the housing G. The rotor R of the electric motor E can drive a rotor shaft 3 which rotates about a (second) axis of rotation D2. The (second) drive torque of the rotor shaft 3 can be transmitted to the output shaft 2 of the drive unit a via the planetary gear 5 of the drive unit a of the gears 4, 5 arranged within the housing G.
The sun gear 35 of the planetary gear 5 is connected in a rotationally fixed manner to the rotor shaft 3. The sun gear 35 meshes with the planet gears 51A, 51B of the planet carrier 52 of the planetary gear 5. The planet wheels 51A and 51B in turn mesh with a ring gear 50 of the planetary gear 5, which is fixed relative to the housing, in order to convert the rotation of the rotor shaft 3 into a slower rotation of a planet carrier 52, which is connected in a rotationally fixed manner to the driven shaft 2.
The driven shaft 2 is thus arranged coaxially with the rotor shaft 3 and protrudes from the housing G with one shaft end on one side of the housing G. A driven element in the form of a driven gear or driven pulley 20 is provided at this shaft end of the driven shaft 2 which protrudes from the housing G. The driven gear or driven pulley 20 is connected to a transmission link (e.g., a chain or belt) to transmit torque for driving the electric bicycle to a wheel of the electric bicycle, e.g., to a rear wheel.
For driving the output shaft 2 and the output gear or output pulley 20 fixed to the output shaft in a rotationally fixed manner, a center shaft or output shaft 1 is arranged next to the electric motor E, which extends through the housing G and projects with both shaft ends on opposite sides of the housing G. A pedal for the controlled introduction of a (first) drive torque by muscle force can be attached to the protruding shaft end of the drive shaft 1.
For transmitting the first drive torque from the drive shaft 1 to the driven shaft 2, the transmissions 4, 5 of the drive unit a comprise, in addition to the planetary transmission 5 coupling the rotor shaft 3 to the driven shaft 2, at least one further transmission stage 4 of a spur gear or belt transmission. The rotation of the drive shaft 1 is made faster via the at least one gear stage 4. Thus, in the present case, the drive shaft 1 extends parallel to the driven shaft 2. The drive axis of rotation D1 of the drive shaft 1 thus extends parallel to the (driven) axis of rotation D2 of the driven shaft 2 about which the coaxially arranged rotor shaft 3 can also rotate.
Thus, via the gear stage 4, for example, a first gearwheel or pulley 10, which is connected in a rotationally fixed manner to the drive shaft, is coupled to a transmission element in the form of a second gearwheel or pulley, which is coupled to the driven shaft, in order to transmit a first drive torque introduced on the user side to the driven shaft 2. Due to the parallel arrangement of the drive shaft 1 and the driven shaft 2, the torque acting on the drive train and its switching mechanism is relatively low when the drive unit a is mounted on an electric bicycle as prescribed. Furthermore, it is also possible to use a relatively light drive shaft 1, which is embodied, for example, as an aluminum shaft.
In addition, the drive unit a of fig. 1 is provided with a rotor-side one-way clutch FL3 between the rotor R and the rotor shaft 3, and a transmission-side one-way clutch FL2 between the second gear or pulley 21 and the driven shaft 2. By this arrangement of the one-way clutches FL3 and FL2, the drive unit a with the housing G is made relatively small and inexpensive. Relatively few components are required for torque transmission and coupling.
List of reference numerals
1. Drive shaft/center shaft
10. First gear/pulley
2. Driven shaft
20. Driven gear/driven pulley (driven element)
21. Second gear/belt wheel (Transmission element)
3. Rotor shaft
35. Sun gear
4. Transmission stage
5. Planetary transmission mechanism
50. Gear ring
51A, 51B planetary gear
52. Planet carrier
A drive unit
D1 Driving the axis of rotation
D2 Driven rotation axis
E electric motor
FL1, FL2 one-way clutch
G shell
And R rotor.
Claims (8)
1. A drive unit for an electric bicycle, the drive unit having:
a driven shaft (2) for providing a torque for driving the electric bicycle,
a drive shaft (1) rotatable about a drive rotation axis (D1) for generating a first drive torque by muscle force manipulation by a rider of the electric bicycle,
-an electric motor (E) for generating a second driving torque by external power steering on a rotor shaft (3) coupled to the electric motor (E), and
a transmission (4, 5) having at least one planetary transmission (5) for transmitting a first and a second drive torque to the output shaft (2),
it is characterized in that the method comprises the steps of,
the rotor shaft (3) and the driven shaft (2) are arranged coaxially to each other, and the drive rotation axis (D1) extends parallel to the rotor shaft (3) and the driven shaft (2).
2. Drive unit according to claim 1, characterized in that the rotor shaft (3) is coupled with a sun gear (35) of the planetary transmission (5).
3. Drive unit according to claim 1 or 2, characterized in that the rotor shaft (3) is coupled with the rotor (R) of the electric motor (E) via a one-way clutch (FL 3).
4. A drive unit according to any one of claims 1 to 3, characterized in that the driven shaft (2) is coupled with a planet carrier (52) of the planetary transmission (5).
5. Drive unit according to any of the preceding claims, characterized in that the transmission means (4, 5) comprise at least one transmission stage (4) between the driven shaft (2) and the drive shaft (1).
6. Drive unit according to claim 5, characterized in that at least one gear stage (4) arranged between the driven shaft (2) and the drive shaft (1) is formed by a spur gear transmission or a belt transmission of the transmission (4, 5).
7. Drive unit according to claim 5 or 6, characterized in that at least one gear stage (4) arranged between the driven shaft (2) and the drive shaft (1) comprises a rotatable transmission element (21) which is coupled with the driven shaft (2) via a one-way clutch (FL 2).
8. Electric bicycle having a drive unit according to any of the preceding claims.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE102021111477.2A DE102021111477A1 (en) | 2021-05-04 | 2021-05-04 | Drive unit for an electric bicycle |
| DE102021111477.2 | 2021-05-04 | ||
| PCT/EP2022/061695 WO2022233779A1 (en) | 2021-05-04 | 2022-05-02 | Drive unit for an electric bicycle |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117529433A true CN117529433A (en) | 2024-02-06 |
Family
ID=81850064
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202280033399.6A Pending CN117529433A (en) | 2021-05-04 | 2022-05-02 | Drive unit for electric bicycle |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP4334197A1 (en) |
| CN (1) | CN117529433A (en) |
| DE (1) | DE102021111477A1 (en) |
| WO (1) | WO2022233779A1 (en) |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3939862B2 (en) * | 1998-08-18 | 2007-07-04 | ヤマハ発動機株式会社 | Motor drive unit for electric bicycle |
| CN100406343C (en) * | 2004-09-27 | 2008-07-30 | 捷安特(中国)有限公司 | Electric bicycle central drive coaxial power set |
| BE1026017B1 (en) * | 2018-02-16 | 2019-09-16 | E2 Drives Sa | Powertrain |
| DE102018217883B4 (en) * | 2018-09-25 | 2020-06-04 | Zf Friedrichshafen Ag | Drive arrangement for a bicycle or pedelec |
-
2021
- 2021-05-04 DE DE102021111477.2A patent/DE102021111477A1/en active Pending
-
2022
- 2022-05-02 WO PCT/EP2022/061695 patent/WO2022233779A1/en active Application Filing
- 2022-05-02 EP EP22725903.3A patent/EP4334197A1/en active Pending
- 2022-05-02 CN CN202280033399.6A patent/CN117529433A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| DE102021111477A1 (en) | 2022-11-10 |
| WO2022233779A1 (en) | 2022-11-10 |
| EP4334197A1 (en) | 2024-03-13 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination |