Drive unit of a vehicle which can be driven by muscle power and / or motor power

Abstract

The invention relates to a drive unit of a vehicle (100) which can be driven by muscle power and / or motor power, in particular an electric bicycle, comprising a motor (2) having a driven shaft (22), an output shaft (3) and a transmission (4), wherein the transmission is designed to transmit torque between the driven shaft and the output shaft, wherein the driven shaft is arranged coaxially to the output shaft, wherein the transmission has an intermediate shaft (45) which is arranged parallel to the output shaft, wherein the transmission also has an intermediate gearwheel (49) which is arranged between the intermediate shaft and the output shaft, and wherein the transmission is designed to transmit torque between the driven shaft and the output shaft via the intermediate shaft and via the intermediate gearwheel.

Description

[0001] Description

[0002] title

[0003] State of the art

[0004] The present invention relates to a drive unit of a vehicle operable with muscle power and / or motor power, and to a vehicle operable with muscle power and / or motor power.

[0005] Drive units for vehicles powered by human and / or motor power, such as electric bicycles, are known, which comprise gears between a motor and an output shaft. A spur gear arrangement is often used, with a motor whose output shaft is arranged parallel to the output shaft and spaced from it. Drive units with a motor arranged coaxially to the output shaft, with a planetary gear for torque transmission, are also known.

[0006] Disclosure of the invention

[0007] The drive unit according to the invention with the features of claim 1 is distinguished by a particularly advantageous design and high efficiency. In particular, a particularly compact overall design of the drive unit can be enabled, while at the same time a high degree of power transmission can be enabled. Furthermore, the design allows for a high degree of flexibility in dimensioning the drive unit for different loads. This is achieved according to the invention by a drive unit of a vehicle that can be operated with muscle power and / or motor power, preferably an electric bicycle, comprising a motor with an output shaft, an output shaft, and a transmission. The transmission is designed and arranged to transmit torque between the output shaft of the motor and the output shaft. The output shaft, and preferably the motor, is arranged coaxially to the output shaft.The transmission has an intermediate shaft arranged parallel to the output shaft. Furthermore, the transmission includes an additional intermediate gear, which is arranged between the intermediate shaft and the output shaft, particularly with respect to a torque transmission path. The transmission is configured to transmit torque between the output shaft and the output shaft via the intermediate shaft and the intermediate gear.

[0008] The output shaft in particular has an output interface. In particular, the output interface is configured for connection to an output element. A chainring can preferably be provided as the output element. Alternatively, another output element can be provided which is configured for connection to a transmission element, for example a chain, in order to enable torque transmission from a pedal shaft to a drive wheel of the vehicle. The output shaft of the drive unit can be designed as a hollow shaft. The drive unit in particular has a pedal shaft, which is arranged in particular coaxially within the hollow shaft. The pedal shaft can be connected in a rotationally fixed manner to cranks of the electric bicycle such that the pedal shaft can be driven by the rider's pedaling force. Alternatively, the output shaft of the drive unit can be formed integrally with a pedal shaft of the drive unit.The output interface can be connected directly or indirectly to the pedal shaft.

[0009] The transmission is preferably designed as a spur gear. In particular, a spur gear is considered to be a transmission with multiple gears, wherein the toothings of all gears are each formed, in particular exclusively, on an outer circumference of the corresponding gear. In particular, respective gears that mesh with one another are arranged rotatably about separate axes. In particular, the intermediate shaft and intermediate gear are arranged rotatably about separate, and preferably spaced-apart, axes.

[0010] In other words, a coaxial arrangement of the motor output shaft and the output shaft is provided, whereby torque transmission between the output shaft and the output shaft is enabled via the transmission, preferably designed as a spur gear. The transmission comprises an intermediate shaft and an intermediate gear, via which the torque is transmitted. This means that an engine torque provided, for example, by the motor at the output shaft is preferably transmitted to the intermediate shaft, then from the intermediate shaft to the intermediate gear, and then from the intermediate gear to the output shaft.

[0011] The drive unit therefore offers the advantage that the coaxial arrangement of the output shaft and output shaft, and preferably also of the motor and output shaft, enables a particularly compact design of the drive unit. This makes it possible for the motor, which often takes up a considerable proportion of the overall installation space of the drive unit, to be optimally positioned coaxially with the output shaft. In addition, the drive unit is characterized by low costs due to fewer and relatively simple components. This also enables a low weight of the drive unit. The intermediate shaft allows the transmission to be provided with a predetermined gear ratio between the output shaft and output shaft in a particularly simple manner and with few components.In addition, a gear ratio can be easily adjusted, for example, by scaling the intermediate shaft, in particular with appropriate gears. The intermediate gear also allows for an optimal gear ratio and high flexibility of the drive unit to be provided with a simple design. In detail, the additional intermediate gear can easily enable flexible adjustment of the gear ratio for drive units with different mechanical dimensions. For example, the overall size of the drive unit can be essentially maintained even when the overall gear ratio is changed, for example, by adjusting individual or multiple gear stages, thus keeping it particularly compact.

[0012] The subclaims contain preferred developments of the invention.

[0013] Particularly preferably, the transmission comprises a first gear and a second gear. The first gear and the second gear are each connected to the intermediate shaft in a rotationally fixed manner. For example, the first gear, the second gear, and the intermediate shaft can be formed together as a single, integral component. The second gear meshes with the intermediate gear. This allows for a simple, cost-effective, and robust design.

[0014] The transmission preferably has motor gearing formed on the output shaft. In particular, a portion of the output shaft is thus designed as a gear with the motor gearing. The first gear meshes with the motor gearing. This further advantageously facilitates a compact, simple, and cost-effective design.

[0015] The transmission further preferably has a third gear that can be connected to the output shaft in a rotationally fixed manner. In particular, the third gear can additionally be arranged to rotate relative to the output shaft in a freewheeling mode. The third gear meshes with the intermediate gear. In particular, the torque can thus be transmitted from the intermediate gear to the output shaft via the third gear. The intermediate gear effects torque transmission between the second gear and the third gear without any gearing or reduction.

[0016] Particularly preferably, an outer dimension of the intermediate gear is smaller than an outer dimension of the third gear. Preferably, the outer dimension of the intermediate gear is larger than an outer dimension of the second gear. This means that the size of the intermediate gear is preferably between the sizes of the first gear and the third gear. This allows the compactness of the drive unit and the overall transmission ratio of the transmission to be optimized particularly easily and effectively.

[0017] Preferably, the first gear and the third gear have the largest outer dimensions of the gears of the transmission. This means that the first gear and the third gear form the largest gears of the transmission, with all other gears having smaller outer dimensions. This allows for a high overall transmission ratio.

[0018] Preferably, the second gear and the motor gearing have the smallest external dimensions of the gears of the transmission. This means that the second gear and the motor gearing form the smallest gears of the transmission, with all other gears having larger external dimensions. This further advantageously allows for a high overall transmission ratio with a compact drive unit design.

[0019] In particular, the outer dimension is always considered to be an outer diameter, for example a tip diameter, or alternatively a pitch diameter, of a corresponding toothing of the respective gear.

[0020] Particularly preferably, the drive unit further comprises a freewheel between the third gear and the output shaft. In particular, the freewheel is designed to be able to switch between a rotationally fixed connection and a relatively freely rotatable connection between the third gear and the output shaft. Preferably, the freewheel locks in the drive direction of the motor and opens when the motor is stationary and during actuation of the cranks. Alternatively or additionally, the freewheel can be designed to be controllably actuated, for example by means of a control unit. In particular, the freewheel can thus be decoupled from the output shaft, for example to switch off the motor assistance, in particular when a predetermined speed of the vehicle is exceeded.

[0021] For example, in a preferred alternative embodiment, the third gear can be formed in a rotationally fixed manner with a hollow shaft on which the output interface is arranged. In this case, the freewheel between the third gear and the output shaft can act as a driver's freewheel, i.e., to enable a rotationally fixed or relatively freely rotatable connection between the output interface and the output shaft.

[0022] Preferably, the transmission is designed as a three-stage spur gear transmission. This means that three spur gear stages are provided to provide a predetermined gear ratio between the output shaft and the output shaft. This allows for optimal torque transmission of the drive unit with a high gear ratio for use in an electric bicycle, while maintaining a compact design and simple construction.

[0023] The motor is in particular an internal rotor motor.

[0024] Particularly preferably, the motor has a stator with a predetermined outer dimension. An outer dimension of the third gear is smaller than or equal to the outer dimension of the stator. In particular, an outer diameter is considered an outer dimension. This means that the third gear is not larger than the stator of the motor. This allows for a particularly advantageous, compact geometry of the drive unit, particularly in the area of ​​the motor. The stator of the motor thus forms, for example, the largest element on the axis of the output shaft.

[0025] Further preferably, the intermediate gear is rotatably mounted about an intermediate gear axis. The intermediate gear axis is, in particular, a fixed axis. This allows for a space-saving design. Alternatively, the intermediate gear axis can also be rotatably mounted in the housing. The intermediate gear axis is arranged parallel to an intermediate shaft axis of the intermediate shaft. In particular, the intermediate gear axis and the intermediate shaft axis are arranged at a predetermined distance from one another.

[0026] Preferably, the intermediate gear axis, the intermediate shaft axis, and the crank axis lie in a common plane. In other words, the intermediate gear axis lies on a straight line exactly between the intermediate shaft axis and the crank axis. This makes it possible to provide a particularly compact drive unit, particularly in the vertical direction. Preferably, the intermediate gear axis and the intermediate shaft axis lie in a common plane, with the intermediate gear axis and the crank axis lying in a further, different plane. The two planes intersect in the intermediate gear axis at an angle which is at least 45° and in particular less than 180°. Preferably, the angle is at least 60° and at most 110°, with an outer dimension of the intermediate gear preferably being larger than an outer dimension of the second gear.Particularly preferably, the angle is at least 110° and less than 180°, especially if the outer dimension of the second intermediate gear is substantially equal, preferably exactly equal, to the outer dimension of the second gear. In particular, a deviation of the outer dimensions of a maximum of 5%, in particular a maximum of 3%, from each other is considered to be substantially equal. This enables a particularly advantageous utilization of the installation space, enabling a particularly compact drive unit.

[0027] The output shaft is preferably designed as a hollow shaft. The output shaft is rotatably mounted within the output shaft. Preferably, at least one bearing is provided between the output shaft and the output shaft for rotatable support. By designing the output shaft as a hollow shaft and the output shaft passing through it, a particularly compact geometry of the drive unit can be provided. Furthermore, flexible relative positioning of the drive unit components along the axial direction of the output shaft is enabled.

[0028] More preferably, the drive unit further comprises two bottom brackets. The output shaft is rotatably mounted in a housing of the drive unit by means of the two bottom brackets. The bearings can be designed, for example, as ball bearings, such as deep groove ball bearings, or the like.

[0029] The output shaft preferably has an output interface which is designed for connection to an output element. A chainring can preferably be provided as the output element. Alternatively, another output element can preferably be provided which is designed for connection to a transmission element, such as a chain, in order to enable torque to be transmitted from the output shaft to a drive wheel of the vehicle. For example, the output interface can thus be a receiving element for an output element, such as in particular a chainring. The motor is preferably arranged on a side of the transmission facing away from the output interface. This means that the transmission is arranged closer to the output element than the motor in the axial direction of the output shaft. Alternatively, the motor is preferably arranged on a side of the transmission facing the output interface.In other words, the motor can be arranged on the left or right with respect to a direction of travel of a vehicle on which the drive unit can be arranged.

[0030] Furthermore, the invention leads to a vehicle that can be operated with muscle power and / or motor power, preferably an electric bicycle, which comprises the described drive unit.

[0031] Short description of the drawings

[0032] The invention is described below using an exemplary embodiment in conjunction with the figures. In the figures, functionally identical components are identified by the same reference numerals. Here:

[0033] Figure 1 is a simplified schematic view of a vehicle with a drive unit according to a preferred embodiment of the invention,

[0034] Figure 2 is a perspective detailed view of the drive unit of Figure 1,

[0035] Figure 3 is a detailed sectional view of the drive unit of Figure 1,

[0036] Figure 4 is a further detailed sectional view of the drive unit of Figure 1,

[0037] Figure 5 is a perspective view of the drive unit of Figure 1, and

[0038] Figure 6 is a perspective view of the drive unit of Figure 1 with an alternative geometric configuration. Preferred embodiments of the invention

[0039] Figure 1 shows a simplified schematic view of a vehicle 100 comprising a drive unit 1 according to a preferred embodiment of the invention. The vehicle 100 is a vehicle that can be operated with muscle power and / or motor power, specifically an electric bicycle.

[0040] The drive unit 1 comprises a motor 2 (see Figure 2), which is in particular an electric motor. The motor 2 can be supplied with electrical energy by means of an electrical energy storage device 109 of the electric bicycle 100.

[0041] The motor 2 comprises a stator 21 and a rotor rotatable relative thereto. The stator 21 has a largest outer dimension 21a of the motor 2 (see Figures 5 and 6).

[0042] The drive unit 1 is arranged in the region of a bottom bracket of the electric bicycle 100. The motor torque generated by the motor 2 can provide motor assistance to the pedaling force generated by the muscular power of a rider of the electric bicycle 100.

[0043] The drive unit 1 is shown in detail in Figures 2 to 6 and is described in detail below.

[0044] The drive unit 1 comprises an output shaft 3 to which the engine torque of the motor and a pedaling torque of the driver can be transmitted.

[0045] In addition, the drive unit 1 includes a pedal shaft 33, which is rotationally connected to cranks 104 of the electric bicycle 100. The pedal shaft 33 is driven by the rider's pedaling power.

[0046] Preferably, the output shaft 3 is designed as a hollow shaft, within which the pedal shaft 33 is arranged, in particular coaxially. The rider's pedaling torque can be transmitted from the pedal shaft 33 to the output shaft 3. For example, a freewheel can be arranged between the output shaft 3 and the pedal shaft 33. The output shaft 3 has an output interface 35 (see Figure 2), to which an output element 107 of the electric bicycle 100 is connected in a rotationally fixed manner. In the illustrated embodiment, the output element 107 is designed as a chainring of a chain drive (see Figure 1).

[0047] The drive unit 1 also comprises a housing 9, within which all components of the drive unit 1 are preferably arranged, with the output shaft 3 extending outward from the interior of the housing 9. The output shaft 3 is rotatably mounted in the housing 9 of the drive unit 1 by means of bottom brackets.

[0048] In addition, the drive unit 1 comprises a gearbox 4. The gearbox 4 is designed to transmit torque between an output shaft 22 of the motor 2 and the output shaft 3 (see Figure 2).

[0049] Gearbox 4 is a spur gear. This means that gearbox 4 comprises several gears designed as spur gears that mesh with each other to transmit torque. Their arrangement is described in more detail below.

[0050] In the drive unit 1, the output shaft 22 of the motor 2 and the output shaft 3 are arranged coaxially with each other. This means that the output shaft 22 and the output shaft 3 are each arranged to rotate about a common crank axis 30.

[0051] Output shaft 3 and driven shaft 22 are each rotatably mounted relative to the pedal shaft 33 by means of bearings.

[0052] The output shaft 22 of the motor 2 protrudes axially beyond the rotor and stator 21. A motor toothing 44 is formed on this projecting portion of the output shaft 22.

[0053] The motor toothing 44 is in engagement with a first gear 41 of the

[0054] Gear 4. The first gear 41 is rotationally fixed to an intermediate shaft 45 of the

[0055] Gearbox 4. The intermediate shaft 45 extends along an intermediate shaft axis 40 and is arranged to be freely rotatable about this intermediate shaft axis 40.

[0056] In addition, the transmission 4 includes a second gear 42, which is also rotationally fixedly connected to the intermediate shaft 45. Preferably, the second gear 42 and the intermediate shaft 45, and at least a portion of the first gear 41, can be formed together as a single, integral component.

[0057] In addition, the transmission 4 includes a third gear 43, which is arranged to rotate about the crank axis 30. The third gear 43 has an outer dimension 43a that is smaller than an outer dimension 21a of the stator 21 of the motor 2 (see Figures 5 and 6).

[0058] Furthermore, the transmission 4 comprises an intermediate gear 49, which is arranged with respect to a path of torque transmission between the intermediate shaft 45 and the output shaft 3.

[0059] In detail, the intermediate gear 49 is in engagement with the second gear 42 and the third gear 43.

[0060] The transmission 4 is designed such that an outer dimension 49a of the intermediate gear 49 is smaller than the outer dimension 43a of the third gear 43 and larger than an outer dimension 42a of the second gear 42. Furthermore, the first gear 41 and the third gear 43 have the largest outer dimensions 41a, 43a of the gears of the transmission 4. Furthermore, the second gear 42 and the motor gearing 44 have the smallest outer dimensions 42a, 44a of the gears of the transmission 4.

[0061] The intermediate gear 49 is arranged so as to be freely rotatable about an intermediate gear axis 90, in particular via a bearing 92. The intermediate gear axis 90 is fixed to the housing. For example, in the installed position of the drive unit 1 on the vehicle 100 shown in Figure 1, the intermediate gear axis 90 is arranged between the intermediate shaft axis 40 and the crank axis 30 with respect to the direction of travel A. Furthermore, the intermediate gear axis 90 is arranged vertically below a straight line 80 connecting the crank axis 30 and the intermediate shaft axis 40 (see Figure 5). This allows for a particularly compact external dimension of the drive unit 1, particularly in the longitudinal direction, i.e., with respect to the direction of travel A.

[0062] The intermediate gear axis 90 and the intermediate shaft axis 40 also lie on a common first plane 96 (see Figure 5). The intermediate gear axis 90 and the crank axis 30 also lie on a further common second plane 97. The first plane 96 and the second plane 97 intersect at a predetermined angle 98.

[0063] The angle 98 is greater than 45°, and in particular less than 180°, and in the preferred embodiment shown is approximately 55°.

[0064] The torque generated by the motor 2 can be transmitted from the output shaft 22 via the motor gearing 44 and the first gear 41 to the intermediate shaft 45 and via the second gear 42 to the intermediate gear 49. From the intermediate gear 49, the torque is further transmitted to the third gear 43 and thus to the output shaft 3.

[0065] The intermediate gear 49 is designed in such a way that it only transmits torque without any transmission or reduction.

[0066] The drive unit 1 thus offers the advantage of a particularly compact design of the drive unit 1 thanks to the coaxial arrangement of the rotor 2 and the output shaft 3. The motor 2, which geometrically forms one of the largest elements of the drive unit 1, particularly due to its stator 21, can be positioned particularly advantageously thanks to the coaxial arrangement with the output shaft 3.

[0067] The design of the transmission 4 with the additional intermediate gear 49 offers the advantages of a particularly compact drive unit 1 with a high transmission ratio and, moreover, high flexibility with regard to the intended use. In detail, the intermediate gear 49 advantageously allows the use of a first gear 41 with a particularly large external dimension 41a without requiring a significant enlargement of the drive unit 1 in the forward direction of travel, while simultaneously enabling a high overall transmission ratio of the transmission 4. In particular, this is achieved by the fact that, thanks to the intermediate gear 49, when the first gear 41 is enlarged, and thus the transmission ratio is increased, the external dimension 43a of the third gear 43 can be kept the same.

[0068] This situation is illustrated in Figures 5 and 6, which show the drive unit 1 according to the invention with various geometric dimensions of the first gear 41. For improved clarity, all gears are indicated in Figures 5 and 6 with their external dimensions. The enlargement of the first gear 41 (shown as an example in Figure 6), which causes an increase in the gear ratio, can be "compensated" without additionally enlarging the third gear 43 simply by adjusting the positioning of the intermediate gear 49.

[0069] In the configuration of the drive unit 1 shown in Figure 6, an alternative dimensioning and positioning of the intermediate gear 49 is also present. In detail, an outer dimension 49a of the intermediate gear 49 essentially corresponds to the outer dimension 42a of the second gear 42.

[0070] In addition, the intermediate gear 49 in Figure 6 is arranged such that the intermediate gear axis 90 and the intermediate shaft axis 40 and the crank axis 30 lie on a common plane 95. In other words, the intermediate gear axis 90 lies exactly on the connecting line 80 between the crank axis 30 and the intermediate shaft axis 40.

[0071] A further advantage is that the special design of the drive unit 1 with torque transmission via the intermediate shaft 45 and the intermediate gear 49 allows the use of a spur gear as the transmission 4. Such a spur gear is characterized by a particularly high degree of efficiency, which ensures high efficiency in the operation of the drive unit 1. Furthermore, the drive unit 1 can be provided in a simple manner with few and comparatively simple components, which in particular can reduce the costs for the drive unit 1. Furthermore, weight savings are possible due to the few and compact components of the drive unit 1.

Claims

Claims 1. Drive unit of a vehicle (100) that can be operated with muscle power and / or motor power, in particular an electric bicycle, comprising: a motor (2) with an output shaft (22), an output shaft (3), and a transmission (4), wherein the transmission (4) is designed to transmit torque between the output shaft (22) and the output shaft (3), wherein the output shaft (22) is arranged coaxially to the output shaft (3), wherein the transmission (4) has an intermediate shaft (45) that is arranged parallel to the output shaft (3), wherein the transmission (4) further has an intermediate gear (49) that is arranged between the intermediate shaft (45) and the output shaft (3), and wherein the transmission (4) is designed to transmit torque between the output shaft (22) and the output shaft (3) via the intermediate shaft (45) and via the intermediate gear (49).

2. Drive unit according to claim 1, wherein the transmission (4) has a first gear (41) and a second gear (42), wherein the first gear (41) and the second gear (42) are connected in a rotationally fixed manner to the intermediate shaft (45), and wherein the second gear (42) is in engagement with the intermediate gear (49).

3. Drive unit according to claim 2, wherein the transmission (4) has a motor toothing (44) formed on the output shaft (22), and wherein the first gear (41) is in engagement with the motor toothing (44).

4. Drive unit according to one of claims 2 or 3, wherein the transmission (4) has a third gear (43) which is rotationally fixed to the output shaft (3) connectable, and wherein the third gear (43) engages with the intermediate gear (49).

5. Drive unit according to claim 4, wherein an outer dimension (49a) of the intermediate gear (49) is smaller than an outer dimension (43a) of the third gear (43), and in particular larger than an outer dimension (42a) of the second gear (42).

6. Drive unit according to one of claims 4 or 5, wherein the first gear (41) and the third gear (43) have the largest external dimensions (41a, 43a) of the gears of the transmission (4).

7. Drive unit according to one of claims 3 to 6, wherein the second gear (42) and the motor toothing (44) have the smallest external dimensions (42a, 44a) of the gears of the transmission (4).

8. Drive unit according to one of claims 4 to 7, wherein the motor (2) has a stator (21) with an outer dimension (21a) and the outer dimension (43a) of the third gear (43) is less than or equal to the outer dimension (21a) of the stator (21).

9. Drive unit according to one of the preceding claims, wherein the intermediate gear (49) is rotatably mounted about an intermediate gear axis (90) which is arranged parallel to an intermediate shaft axis (40) of the intermediate shaft (45).

10. Drive unit according to claim 9, wherein the intermediate gear axis (90) and the intermediate shaft axis (40) and a crank axis (30) of the output shaft (3) lie in a common plane (95).

11. Drive unit according to claim 9, wherein the intermediate gear axis (90) and the intermediate shaft axis (40) lie in a common plane (96), and wherein the intermediate gear axis (90) and a crank axis (30) of the output shaft (3) lie in a further plane (97), wherein the two planes (96, 97) in the intermediate gear axis (90) under a Cut at an angle (98) of at least 45° and less than 180°.

12. Drive unit according to one of the preceding claims, wherein the output shaft (22) is designed as a hollow shaft, and wherein the Output shaft (3) is rotatably mounted within the output shaft (22).

13. Drive unit according to one of the preceding claims, wherein the output shaft (3) has an output interface (35) which is designed for connection to an output element (107), in particular wherein the motor (2) is arranged on a side of the transmission (4) facing away from the output interface (35), or wherein the motor (2) is arranged on a side of the transmission (4) facing towards the output interface (35).

14. A vehicle operable by muscle power and / or motor power, in particular an electric bicycle, comprising a drive unit (1) according to one of the preceding claims.

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