Driving device for electric bicycle and electric bicycle

Abstract

The invention discloses a driving device for an electric bicycle and the electric bicycle. In at least one embodiment, a drive device (50) for an electric bicycle (100) has a gearbox (10) with a first drive shaft (1), a second drive shaft (2) and an output element (6). Torque from the first electric motor may be coupled into the gearbox via the first drive shaft. Torque from the second electric motor may be coupled into the gearbox via the second drive shaft. Torque may be removed from the gearbox via the output element. In this process, torques fed via the two drive shafts are transmitted within the gearbox at least partially on different sides of the drive shafts.

Description

Technical Field

[0001] A drive device for an electric bicycle is described in detail. In addition, an electric bicycle is described in detail. Background Art

[0002] Bicycles are a cost-effective, easy-to-use, and emission-free means of transportation. They have also become popular as sports and fitness equipment, and there are types that are particularly suitable for different sports uses.

[0003] In recent years, there has been an increasing enthusiasm for electric bicycles (especially so-called "pedelecs"), despite their large weight and high price. For electric bicycles, it is important to provide a reliable drive system that enables high power transmission. Summary of the Invention

[0004] One problem to be solved is to provide a drive device for an electric bicycle that helps to improve the utilization of available space. Another problem to be solved is to provide an electric bicycle having such a drive device.

[0005] These objects are solved in particular by a drive device for an electric bicycle and an electric bicycle according to the present disclosure. Advantageous embodiments and further developments are apparent from the following description and the drawings.

[0006] First, a drive device for an electric bicycle is described in detail.

[0007] In at least one embodiment, a drive device for an electric bicycle has a gearbox that has a first drive shaft, a second drive shaft, and an output element. The torque of a first electric motor can be coupled into the gearbox via the first drive shaft. The torque of a second electric motor can be coupled into the gearbox via the second drive shaft. Torque can be dissipated from the gearbox via the output element. The torques fed in via the two drive shafts are at least partially transmitted on different sides of the drive shafts within the gearbox.

[0008] Transmitting torque on both sides of the drive shafts enables efficient utilization of the available space of the drive device.

[0009] In particular, the gearbox includes a plurality of gears that mesh with each other. For example, the gearbox converts the rotation of the first drive shaft into the rotation of the output element. Alternatively or additionally, the gearbox can convert the rotation of the second drive shaft into the rotation of the output element. In particular, the gearbox is configured to transmit the torque from the first drive shaft and / or the second drive shaft to the output element. For example, the gearbox is configured such that the first drive shaft and the second drive shaft can rotate independently of each other. For example, the second drive shaft can also rotate independently of the output element.

[0010] The output element can be, for example, a chainring or a chainring carrier or a chainring spider or a pulley.

[0011] The gearbox is designed such that the torque fed into the gearbox via the first drive shaft is at least partly transmitted on one side of the drive shaft. The torque fed into the gearbox via the second drive shaft is at least partly transmitted on the opposite side of the drive shaft. "At least partly" means that the path along which the respective torque is conducted extends at least partly (i.e., partly or completely) on one side of the drive shaft.

[0012] "On different sides of the drive shaft" particularly means on different sides of a virtual plane which, when viewed over the entire length of the two drive shafts, has a minimum quadratic distance to the two drive shafts. For example, the gearbox is designed such that the virtual plane is parallel to the longitudinal axis of the drive shaft. Alternatively or additionally, the gearbox can be configured such that the virtual plane is transverse or perpendicular to the axis of rotation of the output element and / or transverse or perpendicular to the axis of rotation / longitudinal axis of the pedal shaft of the drive device. If the drive device is viewed with a line of sight parallel to the virtual plane and the virtual plane extends in the vertical direction (i.e., from top to bottom), the two different sides are the half-spaces on the right and left of the virtual plane.

[0013] To achieve torque transmission on different sides of the drive shaft, the gearbox includes at least one gear or at least one gear stage on one side of the drive shaft and at least one gear or at least one gear stage on the opposite side of the drive shaft. For example, at least one redirecting gear stage of the gearbox is arranged on one side of the drive shaft and at least one other redirecting gear stage of the gearbox is arranged on the opposite side of the drive shaft.

[0014] In one embodiment, the gearbox is configured such that the torque input from the first drive shaft is directly transferred from the first drive shaft to one side of the drive shaft and the torque input from the second drive shaft is directly transferred from the second drive shaft to the opposite side of the drive shaft. In particular, the torque is obtained from the output shaft in opposite directions away from the drive shaft and the virtual plane.

[0015] According to at least one embodiment, the two drive shafts are located in a common plane. That is, the longitudinal axes of the drive shafts are located in the common plane. Then, the common plane forms the above-mentioned virtual plane. The drive shafts and their longitudinal axes can extend parallel to each other or at an angle, for example, of at most 120° or at most 90° or at most 30° to each other. The longitudinal axes of the two drive shafts intersect at a point in the common plane, for example. The common plane of the two drive shafts is perpendicular to the axis of rotation of the pedal shaft and / or the axis of rotation of the output element, for example.

[0016] According to at least one embodiment, the drive device further includes a first electric motor that is coupled to a first drive shaft, in particular, directly coupled to the first drive shaft. When the first electric motor operates, the first drive shaft is set to rotate by the first electric motor.

[0017] For example, the drive device is configured such that the first electric motor can rotate only in one direction, which corresponds to the propulsion of the electric bicycle. Along this rotation direction, the first electric motor can operate, for example, in a motorized mode and a regenerative mode.

[0018] According to at least one embodiment, the drive device further includes a second electric motor that is coupled to a second drive shaft, in particular, directly coupled to the second drive shaft. When the second electric motor operates, the second drive shaft is set to rotate by the second electric motor.

[0019] In particular, the drive device is configured such that the second electric motor can rotate in two rotation directions (if the brake described below is opened). The second electric motor can operate, for example, in a motorized mode in only one of the two rotation directions. Along this one rotation direction, preferably, the second electric motor can also operate in a regenerative mode. Along the other rotation direction, the second electric motor can operate only in a regenerative mode. Alternatively, however, the second electric motor can also operate in a motorized and regenerative mode in both rotation directions.

[0020] Two elements can be coupled directly or indirectly. "Coupled" here particularly means that the rotation of one element causes the rotation of the other element. In this context, a direct coupling particularly means that there is no change in the rotation direction or transmission between the elements. In this context, an indirect coupling particularly means that there is a change in the rotation direction and / or transmission between the elements. The indirectly coupled elements are coupled to each other via a gear stage, for example. The directly coupled elements can be connected to each other in a rotationally fixed manner.

[0021] For example, the first electric motor forms the main motor. The second electric motor then forms the auxiliary motor, for example. Compared with the auxiliary motor, the main motor has a greater maximum power, in particular, a greater maximum torque. For example, the maximum power or maximum torque of the main motor is at least 1.5 times or at least twice or at least three times greater than the maximum power or maximum torque of the auxiliary motor.

[0022] According to at least one embodiment, the gearbox has a pedal shaft, also referred to as a pedal crankshaft. The pedal shaft extends, for example, transversely or perpendicularly to the drive shaft or the longitudinal axis of the drive shaft. The rotation axis of the output element also extends, for example, transversely or perpendicularly to the longitudinal axis of the drive shaft. In particular, the rotation axis of the output element and the rotation axis of the pedal shaft are parallel or coincident. The drive device is an orthogonal drive, for example.

[0023] According to at least one embodiment, the gearbox is configured to transfer torque from the pedal shaft to the output element to propel the electric bicycle by pedaling. That is, by driving the pedal shaft by pedaling, the electric bicycle can be propelled. For this purpose, the pedal shaft is particularly coupled to the output element via one or more gear stages of the gearbox. The pedal shaft can be coupled to the first gear stage of these gear stages via a flywheel or can be rotationally fixed to the gear of the first gear stage.

[0024] According to at least one embodiment, the gearbox is configured to transfer torque from an electric motor coupled to a first drive shaft to the output element to propel the bicycle by motor assistance. In other words, the gearbox is configured such that the torque acting on the first drive shaft is transferred to the output element at a specific transmission ratio, enabling the electric bicycle to be driven by the motor.

[0025] For example, the speed ratio between the first drive shaft and the output element is between 1:1 and 1:10 or between 1:10 and 1:4, typically about 1:2.

[0026] According to at least one embodiment, the drive device is a parallel hybrid drive. "Hybrid" means that the electric bicycle is propelled by muscle power or by an auxiliary electric motor (in this case, the electric motor coupled to the first drive shaft) or by both together via the drive device. When both act together (i.e., the pedal movement and the auxiliary electric motor), the torque generated by the electric motor and the torque generated by the pedal movement are added at the point of combination. The speed generated by the electric motor at the point of combination and the speed generated by the pedal movement at the point of combination are the same. The point of combination is, for example, the output element or an element of the gearbox that is rotationally fixed to the output element. The term "parallel" results from this addition of torques.

[0027] In contrast, in a series hybrid drive, the auxiliary electric motor is activated by the cyclist (i.e., by the pedaling movement) and superimposes its own speed, such that the output rotates faster (or slower) than the cyclist's pedaling.

[0028] According to at least one embodiment, the gearbox is configured such that the transmission ratio of the torque transfer or speed transfer from the pedal shaft to the output element can be adjusted by rotating a second drive shaft (e.g., by an electric motor). In particular, the second drive shaft can be used to achieve stepless speed change, i.e., a stepless change in the transmission ratio. Thus, the second drive shaft is not used or not mainly used to transfer torque from the second drive shaft to the output element, but is used to adjust the transmission ratio of the gearbox for transferring torque from the pedal shaft to the output element.

[0029] According to at least one embodiment, the gearbox is configured such that rotation of the second drive shaft in one rotational direction increases the transmission ratio, while rotation in the opposite rotational direction decreases the transmission ratio. In particular, the gearbox is designed such that in principle rotation of the second drive shaft in both opposite rotational directions is possible (for example, when the brakes introduced below are released).

[0030] The stationary transmission of the gearbox (i.e., when the second drive shaft is stationary (not rotating)) is predetermined by the design of the gearbox. In the present case, this stationary transmission ratio preferably does not form the lowest gear, i.e., the smallest possible transmission ratio. Instead, the gear or transmission ratio can be increased and decreased (continuously) from the stationary transmission ratio, i.e., by rotating the second drive shaft in one or the other rotational direction. The maximum transmission ratio or highest gear of the gearbox and the lowest transmission ratio or lowest gear of the gearbox depend on the maximum speed at which the second drive shaft can be rotated in one or the other rotational direction. This is determined, for example, by an electric motor coupled to the second drive shaft.

[0031] For example, the (maximum) rotational speed in one rotational direction can be set by maneuvering the electric motor. In the other rotational direction, the resistance to rotation of the electric motor and thus the (maximum) rotational speed can be set, for example, by a corresponding counter voltage. Alternatively or additionally, this can also be achieved by frequency control, pulse width modulation or other control techniques. Alternatively, the (maximum) rotational speed in the other rotational direction can also be specified by maneuvering the electric motor.

[0032] The smallest possible transmission ratio (for example, for uphill driving) and the largest possible transmission ratio (for example, for fast driving) define the speed range (Δn) of the drive device. For example, the stationary transmission lies in the lower half, in particular in the lower third, of this speed range. For example, the stationary transmission ratio lies between n1 + 1 / 4Δn and n1 + 2 / 5Δn or exactly at n1 + 1 / 3Δn. Here, n1 is the predetermined lowest transmission ratio of the drive device, n2 is the predetermined highest transmission ratio of the drive device, and Δn = n2 - n1 is the speed range.

[0033] According to at least one embodiment, the gearbox for adjusting the transmission ratio by rotation of the second drive shaft has a differential, in the form of a bevel gear differential gearbox or a planetary gearbox or a stepped planetary gearbox or a crown gear differential gearbox. For this purpose, the differential is particularly coupled to the first drive shaft and the second drive shaft, the pedal shaft and the output element.

[0034] According to at least one embodiment, the differential is a planetary gearbox. In this case, for example, the second drive shaft is indirectly coupled to the ring gear of the planetary gearbox. The pedal shaft is coupled to the sun gear of the planetary gearbox, in particular, connected in a rotationally fixed manner or coupled via a flywheel. The output element is coupled to the planet carrier of the planetary gearbox, in particular, connected in a rotationally fixed manner. The first drive shaft can be coupled to the planet carrier, in particular, indirectly coupled.

[0035] The rotational axes of the sun gear, ring gear, planet carrier, and planet gears all extend parallel to the rotational axis of the output element or the pedal shaft, for example.

[0036] According to at least one embodiment, the differential is a stepped planetary gearbox. Then, for example, one sun gear of the stepped planetary gearbox is coupled to the second drive shaft, another sun gear of the stepped planetary gearbox is coupled to the output element, and the planet carrier of the stepped planetary gearbox is coupled to the pedal shaft. The planet carrier can be connected to the pedal shaft in a rotationally fixed manner or can be coupled to the pedal shaft via a flywheel.

[0037] According to at least one embodiment, the differential is a bevel gear differential gearbox. The epicyclic gear carrier of the bevel gear differential gearbox is then coupled to the pedal shaft, in particular, connected in a rotationally fixed manner or coupled to the pedal shaft via a flywheel. At least one epicyclic bevel gear is arranged on the epicyclic gear carrier. The output element is coupled to the first main bevel gear of the bevel gear differential gearbox, in particular, connected in a rotationally fixed manner to the first main bevel gear. For example, the first main bevel gear engages with at least one epicyclic bevel gear. The second drive shaft can be coupled to the second main bevel gear of the bevel gear differential gearbox, in particular, indirectly coupled to the second main bevel gear, where the second main bevel gear engages with at least one epicyclic bevel gear. For example, the first drive shaft is coupled to the first main bevel gear, in particular, indirectly coupled.

[0038] One, two, or more epicyclic bevel gears can be arranged on the epicyclic gear carrier, and each of the one, two, or more epicyclic bevel gears engages with the first main bevel gear and the second main bevel gear. The epicyclic bevel gears of the bevel gear differential gearbox can also be referred to as planet gears. The epicyclic gear carrier can also be referred to as an epicyclic gear cage or a differential cage.

[0039] The rotational axes of the two main bevel gears and the epicyclic gear carrier are respectively parallel to the rotational axis of the output element or the pedal shaft. The rotational axes of at least one epicyclic bevel gear are respectively transverse or perpendicular to the rotational axis of the output element or the pedal shaft.

[0040] According to at least one embodiment, the first main bevel gear and the second main bevel gear are arranged on different sides of the drive shaft. In particular, one main bevel gear is located on one side of a virtual plane or a common plane, while one main bevel gear is located on the other side of the virtual plane or the common plane. This enables space savings and a compact design.

[0041] According to at least one embodiment, the gearbox has a bevel gear stage that is coupled on the one hand to a first drive shaft and on the other hand to an output element. This bevel gear stage is also referred to hereinafter as the first bevel gear stage. The bevel gears of the first bevel gear stage are coupled to the output element for torque transmission in at least one rotational direction without changing the rotational speed. This means that the coupling is such that torque can be transmitted from the bevel gear to the output element in at least one rotational direction, where the bevel gear and the output element rotate at the same speed. The rotational axes of the bevel gear and the output element are parallel or coincident. In particular, the bevel gears of the first bevel gear stage are coupled to the output element without an intermediate gear stage. A gear stage is understood to be a pair of gears meshing with each other. For example, the bevel gears of the first bevel gear stage are coupled to the output element (only) via a flywheel or are rotationally fixed to the output element.

[0042] Another bevel gear of the first bevel gear stage can be rotationally fixed to the first drive shaft. Alternatively, a spur gear stage (also referred to hereinafter as the first spur gear stage) can be provided between the first drive shaft and the first bevel gear stage, and the first drive shaft is then coupled to the first bevel gear stage via this spur gear stage. For example, at most one gear stage is connected between the first bevel gear stage and the first drive shaft.

[0043] According to at least one embodiment, the gearbox has another bevel gear stage. This other bevel gear stage is also referred to hereinafter as the second bevel gear stage. The second bevel gear stage is coupled to a second drive shaft. For example, the second drive shaft is then rotationally fixed to the bevel gears of the second bevel gear stage. Alternatively, a spur gear stage can be connected between the second drive shaft and the second bevel gear stage, and the second drive shaft is coupled to the second bevel gear stage via this spur gear stage. This spur gear stage is also referred to hereinafter as the second spur gear stage. For example, at most one gear stage is connected between the second bevel gear stage and the second drive shaft.

[0044] In the case where the differential is a planetary gearbox, the first drive shaft can be coupled to the planet carrier via the first bevel gear stage. In particular, the bevel gears of the first bevel gear stage can be rotationally fixed to the planet carrier. The second drive shaft is coupled to the ring gear of the planetary gearbox, for example, via the second bevel gear stage. In particular, the ring gear can be rotationally fixed to the bevel gears of the second bevel gear stage or can form these bevel gears.

[0045] In the case where the differential is a bevel gear differential gearbox, the first drive shaft is coupled to the first main bevel gear, for example, via a first bevel gear stage. The first main bevel gear can be connected to the bevel gear of the first bevel gear stage in a rotationally fixed manner or can form the bevel gear. The second drive shaft is coupled to the second main bevel gear, for example, via a second bevel gear stage. The second main bevel gear can be connected to the bevel gear of the second bevel gear stage in a rotationally fixed manner or can form the bevel gear.

[0046] According to at least one embodiment, the bevel gear stage and another bevel gear stage are arranged on different sides of the drive shaft. In particular, one bevel gear stage is located on one side of a virtual or common plane, while one bevel gear stage is located on the other side of the virtual or common plane. This enables space savings and a compact design.

[0047] According to at least one embodiment, the differential is a crown gear differential gearbox. The epicyclic gear carrier of the crown gear differential gearbox is then coupled, for example, to the pedal shaft, in particular, connected to the pedal shaft in a rotationally fixed manner or coupled to the pedal shaft via a flywheel. At least one epicyclic spur gear is arranged on the epicyclic gear carrier. The output element is coupled to the first main crown gear of the crown gear differential gearbox, in particular, connected to the first main crown gear in a rotationally fixed manner, for example, the first main crown gear engages with at least one epicyclic spur gear. The second drive shaft can be coupled to the second main crown gear of the crown gear differential gearbox, in particular, indirectly coupled to the second main crown gear, where the second main crown gear engages with at least one epicyclic spur gear. For example, the first drive shaft is coupled to the first main crown gear, in particular, indirectly.

[0048] One, two or more epicyclic spur gears can be arranged on the epicyclic gear carrier, and each of the one, two or more epicyclic spur gears engages with the first main crown gear and the second main crown gear.

[0049] In particular, the rotational axes of the two main crown gears and the epicyclic gear carrier are parallel to the rotational axis of the output element or the pedal shaft. In particular, the rotational axis of at least one epicyclic spur gear is transverse or perpendicular to the rotational axis of the output element or the pedal shaft.

[0050] According to at least one embodiment, the first main crown gear and the second main crown gear are arranged on different sides of the drive shaft. In particular, one main crown gear is located on one side of a virtual or common plane, while one main crown gear is located on the other side of the virtual or common plane. This enables space savings and a compact design.

[0051] According to at least one embodiment, the first electric motor and the second electric motor are arranged one behind the other in the direction of the longitudinal axes of the first drive shaft and the second drive shaft. For example, the first electric motor is arranged between the gearbox and the second electric motor in the direction of the longitudinal axis, or the second electric motor is arranged between the gearbox and the first electric motor in this direction.

[0052] In at least one embodiment, the longitudinal axis of the drive shaft intersects or passes through the pedal shaft substantially at or near the center of the pedal shaft. For example, the intersection point or the closest point is at a distance between 0.4 times and 0.6 times the length of the pedal shaft or between 0.45 times and 0.55 times the length of the pedal shaft from a longitudinal end of the pedal shaft.

[0053] If the longitudinal axis of the drive shaft does not intersect the pedal shaft but extends past the pedal shaft at an inclined angle, the first bevel gear stage and the second bevel gear stage can be designed, for example, as hypoid bevel gear stages.

[0054] According to at least one embodiment, the drive device includes a brake. The brake is assigned to the second drive shaft. In particular, the brake is coupled to the second drive shaft. The brake is configured to counteract the rotation of the second drive shaft in at least one rotational direction, for example, configured to lock or prevent the rotation.

[0055] The brake can be applied directly to the second drive shaft or to an electric motor coupled to the second drive shaft. The brake can be configured to counteract the rotation of the second drive shaft in only one rotational direction or in both rotational directions. In this context, "rotation" of course refers to rotation about the longitudinal axis of the second drive shaft.

[0056] The brake can be configured to completely prevent or lock the rotation in at least one rotational direction. Alternatively or additionally, the brake can be configured such that the braking force exerted by it is adjustable. Thus, depending on the set braking force, the brake can more or less impede the rotation of the second drive shaft in at least one rotational direction, optionally up to and including completely preventing it. For example, complete prevention can be achieved by form-fitting engagement. For example, the impeding of rotation up to and including complete prevention (i.e., adjustment of the braking force) can be achieved by frictional engagement.

[0057] The brake can be mechanically and / or electrically controllable. For example, the braking effect of the brake can be adjusted by an electrical control signal. However, the braking effect of the brake can also be manually adjusted by the operator of the electric bicycle. For example, the brake of the drive device can be or can be coupled to the rear wheel brake and / or the front wheel brake of the electric bicycle such that when the front wheel brake or the rear wheel brake is applied, the braking for the second drive shaft is also applied and then counteracts the rotation of the second drive shaft in at least one rotational direction.

[0058] According to at least one embodiment, the brake is configured to apply a supporting torque that resists the rotation of the second drive shaft when the electric bicycle starts from rest - particularly when a stationary transmission is set - to achieve a rigid start. In particular, the brake is configured such that a corresponding supporting torque counteracts the torque transmitted from the pedal shaft to the second drive shaft during start-up. In this way, the work applied to the manual forward drive can be prevented from being lost during the rotation of the second drive shaft or during the rotation of the (second) electric motor connected to the second drive shaft. In particular, the brake prevents the rotation of the second drive shaft in both rotational directions when starting from rest.

[0059] In at least one embodiment, the brake is a mechanical brake. For example, the brake includes brake pads for clamping a brake disc. The brake disc is, for example, non-rotatably attached to the rotor of the second electric motor or to the second drive shaft itself. Alternatively, the brake may also include one or more pins that engage with grooves when the brake is applied to completely prevent the rotation of the second drive shaft. For example, the brake includes a flywheel for preventing the rotation of the second drive shaft in only one rotational direction.

[0060] According to at least one embodiment, the brake is configured to frictionally generate a braking effect for both rotational directions of the second drive shaft. That is, when the brake is applied, it frictionally cancels the rotation of the second drive shaft in both rotational directions.

[0061] According to at least one embodiment, the brake is configured to brake an existing rotation of the second drive shaft. For example, the brake is configured to brake or cancel the rotation of the second drive shaft when a lower gear than in the stationary transmission is set. Alternatively or additionally, the brake may be configured to brake or cancel the rotation of the second drive shaft when a higher gear than in the stationary transmission is set.

[0062] According to at least one embodiment, the brake can be used to adjust the braking force that cancels the rotation of the second drive shaft. In particular, the friction force with which the brake achieves its braking effect can be increased or decreased.

[0063] In addition, the brake can also be an electromagnetic brake, such as a magnetic brake or an eddy current brake.

[0064] Next, the electric bicycle will be described in detail. In particular, the electric bicycle is an electrically assisted bicycle.

[0065] In at least one embodiment, the electric bicycle includes a drive device according to one of the embodiments described herein. Additionally, the electric bicycle includes a down tube. Two drive shafts extend in the down tube, for example, substantially parallel to the main extension direction of the down tube. For example, the drive shafts are arranged inside the down tube. The first electric motor and the second electric motor may also be arranged in the down tube. In particular, the down tube extends perpendicular to the pedal shaft.

[0066] Since the electric bicycle has a drive device as described herein, all features disclosed in connection with the drive device are also disclosed for the electric bicycle, and all features disclosed in connection with the electric bicycle are also disclosed for the drive device. Description of the Drawings

[0067] Hereinafter, the drive device as described herein and the electric bicycle as described herein will be described in more detail with reference to the accompanying drawings based on exemplary embodiments. The same reference numerals indicate the same elements in the respective drawings. If the elements or components in the respective drawings correspond in their functions, their description will not be repeated for each of the subsequent drawings. For reasons of clarity, corresponding reference numerals may not be provided for the elements in all the drawings.

[0068] In the drawings:

[0069] Figure 1 An exemplary embodiment of an electric bicycle is shown.

[0070] Figures 2 to 7 Various exemplary embodiments of the drive device are shown. Detailed Description

[0071] Figure 1 An electric bicycle 100 with a bicycle frame 70 is schematically shown. The bicycle frame 70 particularly has a lower frame part 60 that forms the down tube. The frame part 60 extends in the direction of the bottom bracket including the pedal shaft 5. The pedal shaft 5 is part of the drive device 50 for the electric bicycle 100.

[0072] Hereinafter Figures 2 to 6 An exemplary embodiment of the drive device 50 is shown. Among them, the bearings for relative rotation between adjacent elements are shown as black rectangles.

[0073] Figure 2 and Figure 3 Exemplary embodiments of the drive device 50 are shown in two different illustrations. The drive device 50 includes a gearbox 10 having two drive shafts 1, 2 and an output element 6. Torque is coupled into the gearbox 10 via the drive shafts 1, 2. Torque can be dissipated from the gearbox 10 via the output element 6.

[0074] In the present case, the first drive shaft 1 and the second drive shaft 2 are located in a common virtual plane which is perpendicular to the axis of rotation of the pedal shaft 5 (and perpendicular to the plane of the paper). Here, the drive shafts 1, 2 are arranged on different sides of the pedal shaft 5. Their longitudinal axes are parallel to each other. Alternatively, the two drive shafts 1, 2 can also be located in a common virtual plane and arranged on the same side of the pedal shaft 5, for example above the pedal shaft. For example, the longitudinal axes of the two pedal shafts then form an angle of at most 30° with each other.

[0075] The drive shafts 1, 2 are each coupled to an electric motor 3, 4. For example, Figure 2 and Figure 3 the drive shafts 1, 2 of the drive device 50 extend in the down tube 60 along the down tube 60 in the fully assembled electric bicycle 100. Then, the two electric motors 3, 4 can be arranged in the down tube 60.

[0076] The first electric motor 3 is configured as the main electric motor for the motor-assisted drive of the electric bicycle. The second electric motor 4 is an auxiliary electric motor which provides a continuously adjustable transmission ratio for the manual drive of the electric bicycle. In particular, the second electric motor 4 has a lower power than the first electric motor 3.

[0077] Figure 2 and Figure 3 the drive device 50 further includes a pedal shaft 5, the left and right sides of which are respectively connected to the pedal cranks or pedals 5a, 5b (only shown in Figure 2 ). By means of the pedals 5a, 5b, the pedal shaft 5 can be set to rotate by a pedaling motion. The pedal shaft 5 extends perpendicular to the drive shafts 1, 2. In Figure 2 and Figure 3 the extension of the drive shafts 1, 2 or their longitudinal axes intersect the pedal shaft 5 at the center, or do not intersect the pedal shaft 5 but extend through the pedal shaft 5 in an inclined manner at the center.

[0078] Figure 2 and Figure 3 the gearbox 10 of the drive device 50 also includes a differential 12 in the form of a bevel gear differential gearbox. The bevel gear differential gearbox 12 has two main bevel gears 127, 128, the axes of rotation of which are parallel to or coincide with the pedal shaft 5. The main bevel gears 127, 128 engage with the epicyclic bevel gear 126. The epicyclic bevel gear 126 is rotatably arranged on the epicyclic gear carrier 125, which is rotationally fixed to the pedal shaft 5.

[0079] The first main bevel gear 127 is rotationally fixed to the output element 6. The output element 6 is, for example, a link or a link carrier or a link star or a pulley. The first main bevel gear 127 is part of the first bevel gear stage 11. The first bevel gear stage 11 is coupled to the first drive shaft 1 via the first spur gear stage 14.

[0080] The second main bevel gear 128 is part of the second bevel gear stage 13, and the second bevel gear stage 13 is coupled to the second drive shaft 2 via the second spur gear stage 15.

[0081] When the pedals 5a, 5b are depressed, the pedal shaft 5 starts to rotate. This rotation is transmitted to the epicyclic gear carrier 125. Accordingly, the epicyclic bevel gear 126 also moves about the axis of rotation of the pedal shaft 5. However, since the epicyclic bevel gear 126 is in meshing engagement with the main bevel gears 127, 128, the movement of the epicyclic bevel gear 126 can be related to the rotation of the epicyclic bevel gear 126 about a rotation axis perpendicular to the pedal shaft 5. The engagement with the main bevel gears 127, 128 in turn causes the main bevel gears 127, 128 to also rotate. Then, this produces, for example, the rotation of the output element 6. In this way, the electric bicycle can be manually propelled, i.e., propelled by pedaling.

[0082] Whether and to what extent the first main bevel gear 127 and thus the output element 6 are driven by the pedaling motion also depends on the second drive shaft 2, which can be driven by the second electric motor 4. The rotation of the second drive shaft 2 produces a superimposed rotation of the second main bevel gear 128. This changes the transmission ratio from the pedal shaft 5 to the output element 6. Depending on the speed and direction of rotation of the second drive shaft 2, the transmission ratio becomes higher or lower. The rotational speed of the second drive shaft 2 can be predeterminated in particular by means of the coupled electric motor.

[0083] Figure 2 and Figure 3 The drive device 50 of also enables additional motor-assisted propulsion of the electric bicycle 100. Via the first spur gear stage 14 and the first bevel gear stage 11, torque can be transmitted from the first electric motor 3 to the output element 6, thereby supporting the propulsion of the electric bicycle by the motor.

[0084] In Figure 3 , the black arrows indicate the torque paths along which the torque is guided from the drive shafts 1, 2 into the gearbox 10. Specifically, due to the arrangement of the elements of the gearbox 10 (such as the gear stages 11, 13, 14, and 15) on the left and right of the drive shafts 1, 2 and on both sides of the left and right of the virtual plane, the following effect is achieved: The torque coupled in via the drive shafts 1, 2 is transmitted at least partially on different sides of the drive shafts 1, 2. The torque is directly led out in opposite directions from the drive shafts 1, 2.

[0085] Figure 4 andFigure 5 Another exemplary embodiment of the drive device 50 is shown again in two different diagrams.

[0086] Differing from Figure 2 and Figure 3 the exemplary embodiments, here a planetary gearbox is used instead of a bevel gear differential as the differential 12. The pedal shaft 5 is connected in a rotationally fixed manner to the sun gear 121 of the planetary gearbox 12. The ring gear 120 of the planetary gearbox 12 is coupled to the second drive shaft 2 via a second bevel gear stage 13 and a second spur gear stage 15. The planet carrier 122 is coupled in a rotationally fixed manner to the output element 6, and the planet gears 123 are rotatably mounted on the planet carrier 122. The planet gears 123 are coupled to the ring gear 120 and the sun gear 121 via tooth engagement.

[0087] When the pedals 5a, 5b are depressed, the pedal shaft 5 begins to rotate. This is transmitted to the sun gear 121, which in turn also rotates about the axis of rotation of the pedal shaft 5. The sun gear 121 meshes with the planet gears 123, which causes them to rotate. This in turn causes the planet carrier 122 to rotate, which in turn causes the output element 6 to rotate.

[0088] The rotation of the ring gear 120 can be adjusted by an electric motor 4 connected to the second drive shaft 2 via its connection to the second drive shaft 2. Depending on the speed and direction of rotation of the ring gear 120, the transmission ratio from the pedal shaft 5 to the planet carrier 122 and thus to the output element 6 changes.

[0089] Differing from Figure 2 and Figure 3 as in, by coupling the first drive shaft 1 to the output element 6 via a first spur gear stage 14 and a first bevel gear stage 11, additional motor-assisted drive of the electric bicycle is also achieved in Figure 4 and Figure 5 The bevel gear 111 of the first bevel gear stage 11 is connected in a rotationally fixed manner to the output element 6.

[0090] Figure 5 The torque path is shown again in. Again, the torque is transmitted on different sides of the drive shafts 1, 2.

[0091] Figure 6Another exemplary embodiment of the drive device 50 is shown, in which a crown gear differential gearbox having a first main crown gear 130 and a second main crown gear 131 is used as the differential 12. Both are in meshing engagement with at least one epicyclic spur gear 129. The epicyclic spur gear 129 is rotatably mounted on the epicyclic gear carrier 125. The epicyclic gear carrier 125 is connected to the pedal shaft 5 in a rotationally fixed manner. The first main crown gear 130 is connected to the output element 6 in a rotationally fixed manner and forms the crown gear of the first crown gear transmission stage 16, which is coupled to the first drive shaft 1. The second main crown gear 131 forms part of the second crown gear transmission stage 17, which is coupled to the second drive shaft 2. The operating principle of the continuously variable transmission ratio adjustment between the pedal shaft 5 and the output element 6, as well as the motor assistance of the first electric motor 3, are the same as in the previous exemplary embodiment.

[0092] In Figure 6 the exemplary embodiment of Figures 2 to 5 the spur gear stages 14, 15 used in Figures 2 to 5 are omitted. In Figure 6 this way, these can also be omitted. In particular, due to the omission of the spur gear stages, one rotational axis of the epicyclic spur gear 129 is offset in the direction of the longitudinal axis of the pedal shaft 5 to the longitudinal axes of the drive shafts 1, 2. Figure 6 The torque path is also shown.

[0093] In Figure 6 this, the drive device 50 additionally includes a brake 7 coupled to the second drive shaft 2. The brake 7 is used to counteract the rotation of the second drive shaft 2 in one or both rotational directions. For this purpose, the brake 7 can completely prevent rotation (e.g., by form-fit or frictional engagement) or only impede rotation when it is actuated (e.g., by frictional engagement). The brake is designed as, for example, a mechanical brake. The brake 7 acts on the second electric motor 4. The brake 7 can be actuated manually and / or electrically. For example, for electrical operation, the brake 7 is signal-connected to the control unit (not shown) of the electric bicycle to receive corresponding control signals. For example, when the bicycle is stationary and a stationary transmission is set, the brake can be activated / set so that the torque applied by the driver during start-up is not wasted in the rotation of the second drive shaft. For example, a "hard" start can be achieved and a pleasant driving experience can be realized.

[0094] Although the brake 7 is only shown in Figure 6 the drive device 50 of Figures 2 to 5 this, such a brake can also be used in

[0095] the drive device 50 of

[0095] In all exemplary embodiments, the transmission of torque on different sides of the drive shafts 1, 2 results in a particularly compact design of the drive device 50.

[0096] In previous exemplary embodiments, the pedal shaft 5 was always connected in a rotationally fixed manner to a component of the differential 12. Alternatively, however, the pedal shaft 5 can also be connected to the component via a flywheel in various cases. Furthermore, in previous exemplary embodiments, the output element 6 was connected in a rotationally fixed manner to the bevel gears 111, 127 of the first bevel gear stage 11 or to the crown gear 130 of the crown gear stage 16. However, a connection via a flywheel between the bevel gears 111, 127 or the crown gear 130 and the output element 6 can also be used instead.

[0097] In Figure 7 the exemplary embodiment, the differential 12 is a stepped planetary gearbox having two sun gears 121, 124 and a planet carrier 122. The planet gears 123a, 123b are rotatably mounted on the planet carrier 122 and engage with the first sun gear 121 or the second sun gear 124. In particular, the planet gears 123a, 123b are connected to each other in a rotationally fixed manner.

[0098] The first sun gear 121 is coupled to the second drive shaft 2 via the second bevel gear stage 13 and the second spur gear stage 15. The second sun gear 124 is connected in a rotationally fixed manner to the output element 6. The planet carrier 122 is coupled to the pedal shaft 5 via a flywheel 9. Alternatively, there can also be a rotationally fixed connection between the pedal shaft 5 and the planet carrier 122.

[0099] Furthermore, a flywheel 8 is provided between the output element 6 and the bevel gear 111 of the first bevel gear stage 11 such that when rotating in one rotational direction, torque can be transmitted from the bevel gear 111 to the output element 6 and the bevel gear 111 and the output element 6 rotate at the same speed. This prevents the electric motor 4 from being "dragged", which results in less resistance when pedaling under operating conditions without motor assistance from the electric motor 4.

[0100] The present invention is not limited to the description based on the exemplary embodiments. Rather, the present invention includes each new feature and each combination of features, in particular each combination of features in the patent claims, even if these features or the combination are not explicitly stated in the patent claims or the exemplary embodiments.

[0101] List of reference numerals

[0102] 1 First drive shaft

[0103] 2 Second drive shaft

[0104] 3 First electric motor

[0105] 4 Second electric motor

[0106] 5 Pedal shaft

[0107] 6 Output components

[0108] 7 Brake

[0109] 8 Flywheel

[0110] 9 Flywheel

[0111] 10 Gearbox

[0112] 11 First bevel gear stage

[0113] 12 Differential

[0114] 13 Second bevel gear stage

[0115] 14 First spur gear stage

[0116] 15 Second spur gear stage

[0117] 16 First crown gear stage

[0118] 17 Second crown gear stage

[0119] 50 Driving device

[0120] 60 Down tube

[0121] 70 Bicycle frame

[0122] 100 Electric bicycle

[0123] 111 Bevel gear

[0124] 120 Ring gear

[0125] 121 Sun gear

[0126] 122 Planet carrier

[0127] 123 Planet gear

[0128] 123a Planet gear

[0129] 123b Planet gear

[0130] 124 Sun gear

[0131] 125 Epicyclic gear carrier

[0132] 126 Epicyclic bevel gear

[0133] 127 First main bevel gear

[0134] 128 Second main bevel gear

[0135] 129 Epicyclic spur gear

[0136] 130 First main crown gear

[0137] 131 Second main crown gear

Claims

1. A driving device (50) for an electric bicycle (100), comprising: a gearbox (10) having a first drive shaft (1), a second drive shaft (2) and an output element (6), - the torque from the first electric motor can be coupled into the gearbox (10) via the first drive shaft (1), - the torque from the second electric motor can be coupled into the gearbox (10) via the second drive shaft (2), - torque can be dissipated from the gearbox (10) via the output element (6), The torque fed in via the two drive shafts (1, 2) is at least partially transmitted in the gearbox (10) on different sides of the drive shafts (1, 2).

2. The driving device according to claim 1, wherein: the gearbox (10) has a bevel gear stage (11) which is coupled to the first drive shaft on the one hand and to the output element (6) on the other hand, The bevel gears (111, 127) of the bevel gear stage (11) are coupled to the output element (6) for transmitting torque in at least one rotational direction without changing the rotational speed.

3. The drive device (50) according to claim 1 or 2, wherein: - The first drive shaft (1) and the second drive shaft (2) extend in a common plane.

4. The driving device (50) according to claim 1 or 2, further comprising: - a first electric motor (3) coupled to the first drive shaft (1), - A second electric motor (4) coupled to the second drive shaft (2).

5. The driving device (50) according to claim 1 or 2, wherein: - the gearbox (10) has a pedal shaft (5) extending transversely or perpendicularly to the drive shafts (1, 2), - The gearbox (10) is configured to transmit torque from the pedal shaft (5) to the output element (6) to propel the electric bicycle (100) by pedaling.

6. The driving device (50) according to claim 1 or 2, wherein: - The gearbox (10) is configured to transmit torque from an electric motor coupled to the first drive shaft (1) to the output element (6) to propel the electric bicycle by motor assistance.

7. The drive device (50) according to claim 5, wherein: The gearbox (10) is configured such that the transmission ratio of the torque transmission from the pedal shaft (5) to the output element (6) can be adjusted by rotating the second drive shaft (2).

8. The drive device (50) according to claim 7, wherein: To set the transmission ratio, the gearbox (10) has a differential (12) in the form of a bevel gear differential gearbox or a planetary gearbox or a stepped planetary gearbox or a crown gear differential gearbox.

9. The drive device (50) according to claim 8, wherein: - the differential (12) is a planetary gearbox, - the second drive shaft (2) is coupled to the ring gear (120) of the planetary gearbox (12), - the pedal shaft (5) is connected to the sun gear (121) of the planetary gearbox (12) in a rotationally fixed manner, The output element (6) is connected in a rotationally fixed manner to the planet carrier (122) of the planetary gearbox (12).

10. The driving device (50) according to claim 8, wherein: - the differential (12) is a stepped planetary gearbox, - the second drive shaft (2) is coupled to the sun gear (121) of the stepped planetary gearbox (12), - the pedal shaft (5) is connected to the planet carrier (122) of the stepped planetary gearbox (12), The output element (6) is coupled to a further sun gear (124) of the stepped planetary gearbox (12).

11. The drive device (50) according to claim 8, wherein: - the differential (12) is a bevel gear differential gearbox, - the epicyclic gear carrier (125) of the bevel gear differential gearbox (12) is connected to the pedal shaft (5) in a rotationally fixed manner, - at least one epicyclic bevel gear (126) is arranged on the epicyclic gear carrier (125), the output element (6) is coupled in a rotationally fixed manner to a first main bevel gear (127) of the bevel gear differential gearbox (12), the first main bevel gear (127) being engaged with the at least one epicyclic bevel gear (126), The second drive shaft (2) is coupled to a second main bevel gear (128) of the bevel gear differential gearbox (12), the second main bevel gear (128) being engaged with the at least one epicyclic bevel gear (126).

12. The drive device (50) according to claim 11, wherein: The first main bevel gear (127) and the second main bevel gear (128) are arranged on different sides of the drive shaft (1, 2).

13. The drive device (50) according to claim 2, wherein: The gearbox (10) has a further bevel gear stage (13) coupled to the second drive shaft (2).

14. The drive device (50) according to claim 13, wherein: The bevel gear stage (11) and the further bevel gear stage (13) are arranged on different sides of the drive shaft (1, 2).

15. The driving device (50) according to claim 8, wherein: - the differential (12) is a crown gear differential gearbox, - the epicyclic gear carrier (125) of the crown gear differential gearbox (12) is connected to the pedal shaft (5) in a rotationally fixed manner, - at least one epicyclic spur gear (129) is arranged on said epicyclic gear carrier (125), the output element (6) is coupled in a rotationally fixed manner to a first main crown gear (130) of the crown gear differential gearbox (12), the first main crown gear (130) being engaged with the at least one epicyclic spur gear (129), The second drive shaft (2) is coupled to a second main crown gear (131) of the crown gear differential gearbox (12), the second main crown gear (131) being engaged with the at least one epicyclic spur gear (129).

16. The drive device (50) according to claim 15, wherein: The first main crown gear (130) and the second main crown gear (131) are arranged on different sides of the drive shaft (1, 2).

17. An electric bicycle (100), comprising: - a drive device (50) according to claim 1 or 2, - a lower tube (60), wherein - The two drive shafts (1, 2) extend in the lower tube (60).

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