DE102014221127B4 - Electric drive for a vehicle and vehicle with the electric drive - Google Patents

Abstract

Electric drive (1) for a vehicle (2)
with an electric motor (5),
with two outputs (7a, b) for outputting a driving torque,
with a transmission section (6) for the transmission of the drive torque from the electric motor (5) to the two outputs (7a, b) of the electric drive (1),
the transmission section (6) having a differential device (10), the differential device (10) having a first and a second sun gear (11, 12) and a set of first planetary gears (15) and a set of second planetary gears (16), the sun gears (11, 12) defining a main axis of rotation (H) of the gear section (6),
wherein the sun gears (11,12) are operatively connected to the outputs (7a, b), wherein the first planet gears (15) mesh with the first sun gear (11) and the second planet gears (16) with the second sun gear (12) a first planetary gear (15) with two second planetary gears (16) and a second planetary gear (16) with two first planetary gears (15) mesh, so that in a circumferential direction about the main axis of rotation (H) continuous ring gear (26) of the first and second planet wheels (15, 16),
wherein the first and second planet gears (15, 16) each have the same number of teeth, and wherein the first and second sun gears (11, 12) each have the same number of teeth,
characterized in that
the first planetary gears (15) are formed as long planetary gears, which extend in the axial direction to the main axis of rotation (H) at least in sections over the second sun gear (12), wherein the second sun gear (12) compared to the first sun gear (11) has a smaller tip diameter.

Description

The invention relates to an electric drive for a vehicle with an electric motor, with two outputs for outputting a drive torque, with a transmission section for transferring the drive torque from the electric motor to the two outputs of the electric drive, wherein the transmission section has a differential device, wherein the differential device comprises a first and a second sun gear and a set of first planetary gears and a set of second planetary gears, wherein the sun gears define a main axis of rotation of the gear portion, the sun gears are operatively connected to the outputs, wherein the first planetary gears with the first sun gear and the second planetary gears with the second Combine sun gear, wherein a first planetary gear with two second planetary gears and a second planetary gear mesh with two first planetary gears, so that a continuous in the direction of rotation about the main axis of rotation Zahnk ration of first and second planetary gears forms, and wherein the first and the second planetary gears each have the same number of teeth and wherein the first and the second sun gear each having the same number of teeth. The invention further relates to a vehicle with this electric drive.

In the realization of hybrid vehicles or electric vehicles, new design options for the integration of electric motors have emerged. The boundary conditions to the design options, however, form the usual requirements for a drive, namely a robust design and a space-adapted implementation.

The publication DE 1555887 A1 , which is probably the closest prior art, relates to a rotation limiting differential, which according to the 8th and the associated description may have as drive a electric motor. In one embodiment, the differential has externally toothed spur gears as output elements. Further, the differential comprises two sets of planetary gears which operate as differential gears, the planet gears in their entirety forming a continuous ring gear about a main axis of rotation of the rotation limiting differential.

The US 3 292 456 A shows an electric drive with a differential device with two sun gears and two sets planetary gears DE 10 2012 220 970 A1 shows an electric drive train ( 1 ) With a gear for the translation of electric torque with two planetary gear sets, each forming a planetary stage, and a third gear stage.

The DE 10 2009 032 286 A1 shows a spur gear with two suns with the same number of teeth, each associated with a set planetary gears, the teeth of the sun are arranged on top circles with different diameters.

WO 2012/079 751 A1 shows a transmission with a transmission section with in each case designed as a planetary stage input stage and load stage and designed as a spur gear differential stage.

The US Pat. No. 1,203,085 A shows a Drehbegrenzungsdifferential with a Kronenradgehäuse whose longitudinal bores serve as supports for two sets of sets of spur gears or screw pinions. It is an object of the present invention to provide an electric drive for a vehicle, which is formed compact and reliable. It is a further object of the invention to propose a corresponding vehicle. These objects are achieved by an electric drive with the features of claim 1 and by a vehicle having the features of claim 10. Preferred or advantageous embodiments of the invention will become apparent from the dependent claims, the following description and the accompanying drawings.

The subject of the invention is thus an electric drive which is suitable and / or designed for a vehicle. The vehicle is particularly preferably a passenger car, it may alternatively be a lorry, a bus or another mobile. The electric drive is designed, in particular, to accelerate the vehicle to a speed of more than 50 kilometers per hour.

The electric drive comprises an electric motor, which serves to generate a drive torque. In possible embodiments of the invention, the electric motor forms the only driving torque generator of the vehicle. In this embodiment, the vehicle is designed as an electric vehicle. In alternative embodiments of the invention, the electric motor can also provide a driving part torque, wherein the vehicle is preferably designed as a hybrid vehicle or as an electric vehicle with a plurality of electric motors.

The electric drive has two outputs for outputting the drive torque or the converted drive torque of the electric motor. Particularly preferably, the two outputs are assigned to the wheels of a common axle of the vehicle or drive them. Thus, the electric drive preferably forms an electrical axis for the vehicle. The outputs can be coupled directly and / or rotationally fixed to the wheels. Alternatively, intermediate gear stages may be provided.

The electric drive has a transmission section, which is designed to transfer the drive torque from the electric motor to the two outputs of the electric drive. Thus, during operation, a torque path results, which leads from the electric motor via the transmission section to the two outputs. It is particularly preferably provided that the transmission section has a conversion, in particular a translation or reduction - hereinafter collectively referred to as translation - has. In particular, the ratio is designed to reduce the speed of the higher rotating electric motor to a lower speed of the slower rotating outputs of the electric drive. Preferably, the total ratio of the gear portion of the electric motor to the outputs between 8th and 15 , preferably at 10 ,

The transmission section has a differential device, which is particularly preferably designed as a transverse differential. The differential device serves to distribute the drive torque to the two outputs. It is particularly provided that when driving straight ahead on a uniform surface of the vehicle, the drive torque is distributed in half or equal to the two outputs. When cornering or with different ground, the differential device can distribute the torque in a different ratio and / or implement a relative rotation between the two outputs. In particular, the differential device is designed as a self-locking differential device.

The differential device has a first and a second sun gear. In particular, the first and the second sun gear is formed as an externally toothed spur gear. The sun gears are operatively connected to the outputs, in particular rotatably coupled. In particular, the sun gears form the output wheels of the differential device. For the description, it is defined that at least one, preferably both sun gears, define a main axis of rotation of the transmission section. In particular, the axis of rotation of the sun gear (s) define the main axis of rotation.

Further, the differential device comprises a set of first planetary gears and a set of second planetary gears, wherein the first planet gears mesh with the first sun gear and the second planetary gears mesh with the second sun gear. In contrast, the first planetary gears are arranged without engagement with the second sun gear and arranged the second planetary gears to the first sun gear without engagement. However, it is envisaged that one, in particular each of the first planetary gears respectively meshes with two second planetary gears and in particular each of the second planetary gears each with two first planetary gears. In particular, the first and the second planet gears are alternately arranged in the direction of rotation about the main axis of rotation and / or alternately operatively connected. As a result, a ring gear which is continuous in the direction of rotation about the main axis of rotation - preferably also called full circle engagement - results from first and second planetary gears. The planet gears form differential gears in the differential device. The axes of rotation of the planet gears are aligned parallel to the main axis of rotation and arranged offset to this.

The first and second planet gears each have the same number of teeth and optionally in addition the same module. Furthermore, the first and second sun gear each have the same number of teeth and optionally additionally the same module. This ensures that the translations in the differential device are the same for both outputs. The first and second planet gears are arranged and / or mounted on a common planet carrier, wherein the planet carrier forms the input to the differential device.

In the context of the invention it is proposed that the first planetary gears are formed as long planetary gears, which extend in the axial direction to the main axis of rotation at least in sections over the second sun gear, in particular via the toothing of the second sun gear. In order for the second sun gear to be disposed without engagement with the first planetary gears, the second sun gear has a smaller tip diameter, in particular outer diameter, compared to the first sun gear. In particular, it is provided that the first planetary gear meshes with the respective second planetary gears in the overlapping area to the second sun gear.

In the context of the invention, an electric drive is thus provided with a differential device, wherein the electric drive is characterized by a high load capacity at the same time low installation space. Due to the ring gear closed in the circumferential direction, the planetary gears, in particular the first and second planetary gears, can be supported in the circumferential direction on the respective adjacent differential gear, in particular in the case of an initial transmission of the drive torque (eg starting), but also during operation of the electric drive. The two-sided support leads to a loading of the differential device with the drive torque that for the planet gears a respective Resulting force is generated, which presses the respective planetary gear radially outwards and not in the toothing of the sun gears. In particular, tilting of the planetary gears about their axis of rotation is avoided by the continuous sprocket. In order to achieve that despite the higher load capacity of the electric drive has a small installation space, the number of tooth planes, which are arranged perpendicular to the main axis of rotation between the planetary gears between each other and between the planetary gears and the sun gears limited to two toothing planes. In particular, the first planetary gears extend as the long planetary gears in the axial direction via the second sun gear, wherein the meshing contact between the first planetary gears and the second planetary gears lies in the same toothing plane as the toothing between the second planetary gears and the second sun gear. In this way, the axial space is significantly reduced compared to designs with three toothing levels. In particular, the teeth of the two sun gears can be arranged directly adjacent to each other, since no further toothing plane is needed, which must be reserved exclusively for the teeth of the planetary gears with each other.

As already explained, the first and second planetary gears form a toothed ring arranged circumferentially around the main axis of rotation of the electric drive. The first and second planetary gears are operatively connected to each other in such a way that there is always a first planetary gear each with a second planetary gear in a first tooth engagement with respect to one side and to the other side in each case. As a result, the respective second planet gear is in each case to one side and to the other side, each with a first planetary gear form-fitting in the first tooth engagement. It follows that viewed in the circumferential direction about the main axis of rotation of each first planetary gear with a second planetary gear and this in turn is in meshing engagement with a first planetary gear. As a first tooth engagement is therefore the engagement of the teeth of a toothing of the first planetary gear in the teeth of a second planetary gear and vice versa to understand, so that the teeth of the first and second planet mesh during the differential action and form a ring gear of planetary gears as differential gears. Consequently, the ring gear is circumferentially positively closed by the first and second planetary gears, which alternate with one another and are in meshing engagement with the neighbor.

In a preferred embodiment of the invention, the teeth of the first and the second sun gear are shifted profile to each other. The tooth profile of a spur gear is defined by a reference profile, by the position of the reference profile line and the generating roller track, and its position to the pitch circle of the teeth. If, in the production of the tooth profile of the toothing, the profile reference line is displaced towards or away from the axis of rotation of the toothed wheel, profile reference line and generating roller circle no longer collapse due to the so-called profile displacement. It may be provided that only the first and the second sun gear have a profile shift each other. In a possible development of the invention, moreover, the first and the second planet gears may also have a profile shift relative to one another. In particular, it is provided that the second sun gear has a negative profile shift compared to the first sun gear, so that the tip circle diameter of the second sun gear is smaller compared to the first sun gear. It can also be provided that the first sun gear has an (absolute) positive profile shift and the second sun gear has an (absolute) negative profile shift.

Optionally additionally, the first planetary gears have a negative profile displacement relative to the second planetary gears. The tip circle diameter of the first planet gears is thus smaller than the tip circle diameter, in particular outside diameter, of the second planet gears. It can also be provided that the first planetary gear has an (absolute) negative profile shift and the second sun gear has an (absolute) positive profile shift. Alternatively or in addition to the profile shift in the planetary gears can also be provided that the pitch circle diameter of the axes of rotation of the second planetary gears is smaller than the pitch circle diameter of the axes of rotation of the first planet gears.

All of the aforementioned measures of the profile shift and the pitch diameter change, optionally together or individually, lead to the result that the first planetary gears are arranged as long planetary gears contactless to the second sun gear, but the transmission ratio between the first planetary gears and the first sun gear and the transmission ratio between is identical to the second planet gears and the second sun gear. Thus, equal ratios in the power flows from the drive of the differential device in the direction of the two outputs or in the opposite direction from the outputs to the input are possible. Thus, a uniform distribution of the drive torque via a heavy duty differential device is implemented with a small space.

In a preferred development of the invention, the first planetary gears, the second planetary gears, the first sun gear and / or the second sun gear on a spur gear. The spur has the advantage that no axial forces arise, so that a high load capacity of the differential device is achieved at the same time with a small space. In less preferred embodiments, helical gearing may be used instead of spur gearing, but with a helix angle of less than 20 degrees. Such helical gearing has the advantage that the noise during operation of the differential device is lower. However, since the differential device only has to implement compensating movements by the relative movement between the planetary gears and the sun gears of the differential device, the actual movement of the differential device during operation is low, so that it is more preferable to use a particularly durable and thus space-saving spur gearing.

It is particularly preferred that the planetary input gear stage and the planetary gear stage are each formed with a helical toothing. In the case of the planetary stages mentioned, the sun gears, planet wheels and ring gear sections constantly roll against each other during operation. As a result of the helical gearing, an axial force is generated as described above, but the smoothness in helical gearing is markedly higher, so helical gearing is preferred for the planetary stages. Preferably, a helix angle greater than 20 degrees, in particular greater than 30 degrees is formed.

In a preferred embodiment of the invention, the first and / or the second planet gears are guided by the headwheel. Thus, the radial position and optionally supplementing the position of the planetary gears in the circumferential direction by guide surfaces of the planet carrier set, which lead the planetary gears on the top circle. For example, the planet carrier as guide surfaces on cylinder walls, in particular cylinder wall sections, which extend parallel to the main axis of rotation. In particular, the first and / or the second planetary gears are formed without rotation axes and / or thus have no mechanical axis of rotation. This realization has the advantage that the planetary gears can be dimensioned smaller in diameter with the same load-bearing capacity, since no weakening has to be introduced into the planet wheels by means of a penetrating axis of rotation or a pivot pin.

It is particularly preferred that the sum of the first and the second planetary gears as a total sum is greater than or equal to 10. Due to the large number of first and second planet gears, the distances in the direction of rotation about the main axis of rotation can also be bridged with planetary gears with a small diameter, so that the radial space of the electric drive remains small.

In a preferred embodiment of the invention, the electric motor is arranged coaxially to the main axis. As a result, the electric drive is particularly compact, since the assemblies of the electric drive position around the main axis, so that the electric drive can be built, for example, in a cylindrical shape.

It is particularly preferred that the transmission section has a planetary gear stage, which is arranged between the electric motor and the differential device. One of the outputs of the differential device is coaxially guided by the at least one planetary gear stage and the electric motor. In particular, the output is formed as a shaft or a shaft portion which is arranged coaxially with the main axis of rotation. This embodiment supports the effort to keep the electric drive compact in the radial and axial directions.

It is further preferred that the differential device and the planetary gear stage have a common planet carrier device. In particular, the planet carrier of the differential device forms part of the planet carrier device. By integrating the function of the planet carrier of the differential device and the planetary gear stage in the planet carrier device further space can be saved. The planetary gear stage is designed in particular as a Stirnradplanetengetriebestufe, wherein the wheels of the Stirnradplanetengetriebestufe are designed as spur gears.

In a possible development of the invention, the transmission section has a planetary input gear stage, wherein the planetary input gear stage is arranged in the drive torque flux or in the torque path between the planetary gear stage and the electric motor. Particularly preferably, an output of the electric motor is non-rotatably connected to an input of the planetary input gear stage. Furthermore, it is preferred that an output of the planetary input gear stage is rotatably connected to an input of the planetary load gear stage. Furthermore, it is preferred that an output of the planetary load gear stage is non-rotatably connected to the input of the differential device. In particular, the torque path between the electric motor and the differential device is designed as an uninterruptible torque path, so that the electric motor is always operatively connected to the differential device and / or in all operating states of the electric drive.

Another object of the invention relates to the vehicle with the electric drive, as described above or according to one of the preceding claims. Particularly preferably, the electric drive forms an electric axle for driving the wheels of an axle of the vehicle.

• 1 eine schematische Darstellung eines Elektroantriebs als ein erstes Ausführungsbeispiel der Erfindung;
• 2 eine schematische Draufsicht auf die Differenzialeinrichtung des Elektroantriebs in der 1;
• 3 eine Explosionsdarstellung einer möglichen konstruktiven Realisierung des Elektroantriebs in der 1;
• 4a, b zwei dreidimensionale Darstellungen einer Planetenträgereinrichtung des Elektroantriebs der vorhergehenden Figuren;
• 5 eine Längsschnittansicht auf eine konstruktive Ausgestaltung eines Getriebeabschnitts des Elektroantriebs der vorhergehenden Figuren.

Further features, advantages and effects of the invention will become apparent from the following description of a preferred embodiment of the invention and the accompanying figures. Showing:

• 1 a schematic representation of an electric drive as a first embodiment of the invention;
• 2 a schematic plan view of the differential device of the electric drive in the 1 ;
• 3 an exploded view of a possible constructive realization of the electric drive in the 1 ;
• 4a, b two three-dimensional representations of a planet carrier device of the electric drive of the preceding figures;
• 5 a longitudinal sectional view of a structural configuration of a gear portion of the electric drive of the preceding figures.

The 1 shows in a highly schematic representation of an electric drive 1 for a vehicle shown as a frame only 2 as an embodiment of the invention. The vehicle 2 For example, is designed as a passenger car and has a driven axle 3 on, which may be formed as a front axle or as a rear axle. The driven axle 3 is in their end areas with wheels 4 coupled as drive wheels. Another axle of the vehicle 2 is not shown.

The electric drive 1 has an electric motor 5 on, which with a transmission section 6 is actively connected. The electric drive 1 or the transmission section 6 has two outputs 7a . b on that with the wheels 4 optionally connected directly rotatably or are operatively connected via a further intermediate gear. The transmission section 6 can - starting from the electric motor 5 - continue into a planetary input gear stage 8th , a planetary gearbox stage 9 and a differential device 10 be divided. The planetary input gear stage 8th and / or the planetary gear stage 9 is an optional component of the electric drive 1 ,

The planetary input gear stage 8th , the planetary gearbox stage 9 as well as the differential device 10 are each formed as a Stirnradplanetengetriebe, the gears of Stirnradplanetengetriebes are each realized as spur gears.

The differential device 10 has a first and a second sun gear 11 . 12 on, being the first sun gear 11 with a first exit 7a and the second sun wheel 12 with the second exit 7b rotatably connected. For example, the first sun wheel is seated 11 on a first output shaft 13 which the first exit 7a forms and the second sun wheel 12 on a second output shaft 14 which the second exit 7b forms. The sun wheels 11 . 12 and / or the output shafts 13 . 14 define a main axis of rotation H of the electric drive 1 , The output of the differential device 10 takes place coaxially with the differential device 10 to the electric drive 1 or to the main axis H , where an output in the form of the output shaft 13 coaxially through the sun gears designed as hollow shafts, namely input sun gear 18 and load sun gear 22 is performed.

The differential device 10 has first planet wheels 15 as well as second planet gears 16 on. The axes of rotation of the first planet gears 15 are located on a first pitch circle diameter D1 , the axes of rotation of the second planet gears 16 are located on a second, smaller pitch circle diameter D2 , The first planet wheels 15 comb with the first sun gear 11 in a first gearing plane VZ 1 , The second planet wheels 16 comb with the second sun gear 12 in a second gearing plane VZ 2 , wherein first toothing plane and second toothing plane VZ 1 . VZ 2 Radial planes to the main axis of rotation H form. It is also envisaged that the first gearing between the first planetary gears 15 and the first sun gear 11 over a first axial tooth width VB1 and the second toothing of the second planet gears 16 with the second sun gear 12 over a second gearing width VB2 in the axial direction to the main axis of rotation H extends. The first planet wheels 15 comb with the second planetary gears 16 in a third tooth width VB3 which at least overlaps the second toothing width VB2 and even congruent to this is arranged in this embodiment. The axial width of the second planet gears 16 is on the second gearing width VB2 and / or to the third gearing width VB3 limited. The axial width of the first planet gears 15 on the other hand, extends over the first tooth width VB1 and overlaps with the second and / or third tooth width VB2 respectively. VB3 , Thus, the first planetary gears 15 formed as a long planet gears, which at least partially over the second sun gear 12 extend in the axial direction.

To a functioning differential device 10 implement, allowed the first planetary gears 15 but not with the second sun gear 12 comb. For this reason it is envisaged that the first planet gears 15 contactless to the second sun gear 12 are arranged. As a further boundary condition is provided that the translation between the first planetary gear 15 and first sun gear 11 equal to the translation of the second planetary gear 16 and the second sun gear 12 should be. In particular, the number of teeth of the sun gears 11 and 12 always the same. Further, the number of teeth of the planet gears 15 and 16 always the same. In particular, it is provided that the module of the planet gears 15 . 16 are the same and the module of the sun gears 11 . 12 are the same.

Like in the 1 is indicated, however, is the tip diameter, in particular the outer diameter of the second sun gear 12 smaller than the tip circle diameter, in particular outside diameter of the first sun gear 11 educated. This is achieved by a profile shift, with the second sun gear 12 opposite the first sun gear 11 has a negative profile shift. Particularly preferably, the first sun gear 11 a positive profile shift and the second sun gear 12 a negative profile shift.

In one embodiment - as in the 1 is shown - is the pitch circle diameter D1 the first planetary gears 15 made larger than the pitch circle diameter D2 the second planetary gears 16 , Instead of or in addition to the different pitch diameters D1 . D2 can the two pitch circle diameter D1 . D2 also be the same design and the first planetary gears 15 opposite the second planet wheels 16 have a negative profile shift. In particular, the first planetary gear 15 a negative profile shift and the second planetary gear 16 a positive profile shift.

Due to the profile displacement is achieved that the second tooth width VB2 and the third tooth width VB3 can be arranged overlapping each other. The use of two instead of three toothing levels significantly axial space in the electric drive 1 saved.

The further transmission section 6 is constructed as follows: The electric motor 5 is coaxial with the major axis H and thus arranged very space-saving. A rotor shaft 17 as an output from the electric motor 5 is non-rotatable with an input sun gear 18 the planetary input gear stage 8th connected. In particular, the rotor shaft 17 with the input sun gear 18 inseparably connected. The entrance sun gear 18 meshes with input planet wheels 19 , which with their axes of rotation in a third pitch circle diameter D3 on an entrance planet carrier 20 are rotatably arranged. The entrance planet wheels 19 mesh with a toothed input Hohlradabschnitt 21 , which are arranged stationary. The entrance planet carrier 20 forms the output from the planetary input gear stage 8th ,

The entrance planet carrier 20 is with a load sun gear 22 non-rotatable, in particular inseparable, connected. The load sun wheel 22 as part of the planetary gearbox stage 9 combs with load planetary wheels 23 which is on a planet carrier 24 on a fourth pitch circle diameter D4 are rotatably arranged. The load planet wheels 23 combing with a Lasthohlradabschnitt 25 , The planet carrier device 24 forms the output from the planetary gearbox stage 9 and at the same time forms the planet carrier for the first and second planet gears 15 . 16 , so the planet carrier device 24 as a common planet carrier or bridge for the Lastplanetenräder 23 , the first planetary gears 15 and the second planet gears 16 are formed. By the formation of the planet carrier device 24 As a common planet carrier components and thus space in the electric drive 1 be saved.

The 2 shows a schematic plan view of the differential device 10 , wherein it can be seen that the first and second planet gears 15 . 16 in a direction of rotation about the main axis of rotation H continuously extending sprocket 26 are arranged. In the direction of rotation around the main axis of rotation H lined up in the sprocket 26 alternately first and second planet gears 15 . 16 on, with each of the planetary gears 15 . 16 is in mesh with both of its adjacent neighbors. Thus, one of the first planetary gears meshes 15 in the direction of rotation with both as the second planet gears 16 trained neighbors. In the same way, each of the second planetary gears meshes 16 with the two adjacent first planetary gears 15 ,

Also clear is the smaller tip diameter of the second sun gear 12 compared to the larger tip diameter of the first sun gear 11 to recognize and the different pitch circle diameter D1 and D2 to recognize, so that the first planet wheels 15 contactless to the second sun gear 12 are arranged.

Through the continuous sprocket 26 introduced drive torques are better distributed, with a passage of the drive torque through the differential device 10 the planet wheels 15 . 16 be loaded radially outward and in particular the meshing between planetary gears 15 . 16 and sun gears 11 . 12 relieve. This forms the differential device 10 a Heavy Duty Differential (HDD).

The planet carrier device 24 has guide surfaces 32 on, which are arc-shaped in the plan view shown plan view, wherein the planetary gears 15 . 16 through the guide surfaces 32 be guided in the radial direction. In particular, it can be provided that the guide surfaces 32 are arranged so that the planetary gears 15 . 16 are guided head and with its circumferential outer side in the radial direction to the own axis of rotation at the guide surfaces 32 issue. This can also be achieved that a certain friction is generated, so that the differential device 10 is designed as a self-locking differential. In addition, due to the top guide of the planetary gears 15 . 16 through the guide surfaces 32 on a central bore in the planet wheels 15 . 16 or omitted by a bolt etc., so that the planet gears 15 . 16 not weakened by this, which in turn the resilience of the differential device 10 and thus the electric drive 1 Benefits in a compact design advantageous.

The 3 shows in a schematic exploded view of the electric drive 1 as a possible structural design. In the 3 is on the right side the differential device 10 and starting from the left side, the planetary input gear stage 8th and the planetary gearbox stage 9 shown. The electric drive 1 has a housing 27 on which the differential device 10 , the planetary gearbox 8th and the planetary gearbox stage 9 receives. In particular, these assemblies are at least flush in the housing in the axial direction 27 added. The housing 27 has a straight cylindrical shape, which is coaxial with the main axis of rotation H is arranged. The housing 27 comprises a housing base 28 and a tubular section housing sleeve 29 on the housing base 28 is placed in the axial direction. To the case 27 , in particular to the housing sleeve 29 , the electric motor can 5 be flanged. The housing body 28 rotates relative to the stationary housing sleeve 29 during operation

Optionally, on the housing body 28 an additional toothing for a parking brake be provided.

Starting from the side of the electric motor 5 indicates the electric drive 1 an optional end cover 30 on. At these closes the Eingangsonnenrad 18 on, which with the input planet gears 19 combs. The entrance planet wheels 19 are in the entrance planet carrier 20 rotatably arranged, with bolts 31 are provided, which are in the axial direction to the main axis of rotation H extending, which at the Eingangsplanetenträger 20 are fixed and on which the input planetary gears 19 are rotatably arranged.

The entrance sun gear 18 and the input planet gears 19 each have a helical toothing, so that they produce only a few vibrations or running noise in continuous operation in the transmission of the drive torque.

The entrance sun gear 18 is with the rotor shaft, not shown 17 rotatably connected, but points - like all other components up to the first sun 11 a central passage opening coaxial with the main axis of rotation H is, wherein through the passage opening, the first output shaft 13 is performed.

On the entrance planet carrier 20 is non-rotating the load sun gear 22 arranged. The load planet wheels 23 are on bolts 33 rotatably mounted and mesh with the load sun gear 22 , Lastsonnenrad 22 and load planet wheels 23 also each have a helical toothing. About the torque path and the planetary input gear stage 8th as well as the planetary gearbox stage 9 is based on a high speed of the electric motor 5 the speed down. Against this background, the planetary input gear stage must 8th transmit a higher speed but a lower torque and the planetary gear stage 9 however, a higher torque, but a lower rotational speed. For this reason, the input sun gear is 18 and the associated input planet wheels 19 narrower in axial width than the load sun gear 22 or the Lastplanetenräder 23 , For example, the axial width of the Eingangsonnenrads 18 half as large or smaller compared to the load sun gear 22 ,

As can be seen in particular from the 4a, b shows that the housing body 28 show this is integrally formed and has a variety of individual functions. The housing body 28 is made of steel in the embodiment shown and realized as a sand casting. He forms the planet carrier device 24 , which on the one hand the Lastplanetenräder 23 or the bolts 33 contributes and on the other hand forms a positive receptacle for the first and second planetary gears 15,16. For this purpose, the housing body 28 a load bridge section 34 and a differential land section 35 on. The load bridge section 34 has at its free end a ring section 36 which is coaxial and concentric with the main axis of rotation H is arranged. From the ring section 36 extend webs in the axial direction 37 which is in the direction of rotation between itself windows 38 have, in each window 38 one of the last planet wheels 23 is arranged. Fixing the bolts 33 has the ring section 36 on one side and the differential land section 35 on the opposite side in each case a bolt receptacle 39 on.

The input hollow wheel section 21 and the load ring gear section 25 in contrast, on the inner surface of the tubular section-shaped housing sleeve 29 as a continuous internal toothing 40 (see. 5 ) educated.

The 5 shows a longitudinal sectional view of the electric drive 1 in the area of the transmission section 6 , where on the left side the differential device 10 , then the planetary gear stage 9 and the planetary input gear stage 8th are shown. It can be seen that the housing body 28 , which again in the Differenzialstegabschnitt 35 and the load land section 34 can be divided, from the tubular section-shaped housing sleeve 29 in the area of the Laststegabschnitts 34 is overlapped, so that the Laststegabschnitt 34 in the tubular section-shaped housing sleeve 29 is arranged. The continuous internal toothing 40 is formed as a helical toothing, which is continuous from the Lastplanetenwädern 23 up to the input planet gears 19 extends.

This particular design shows that the planetary input gear stage 8th and the planetary gearbox stage 9 have the same teeth, as these are both the same continuous internal teeth 40 use. This makes it possible for the load sun gear 22 and the input sun gear 18 to produce from the same, toothed semi-finished product. Furthermore, it is possible to load the load planet wheels 23 and the input planet gears 19 also to produce from the same toothed semi-finished, so that in this way production costs can be saved. In addition, the continuous internal toothing 40 the advantage that the electric drive 1 can be built very compact.

It is provided by way of example that the overall ratio of the transmission section 6 from the entrance of the rotor shaft 17 to the exits 7a . b between 8 and 15 and here is 10 (+/- 10%).

Through the housing body 28 thus becomes a common planet carrier device 24 formed, which from the the electric motor 5 facing side the Lastplanetenräder 23 and on the side facing away from the first and second planet gears 15,16 carries.

As can be seen in particular from the 4a results, the differential land section 35 for each of the first planet gears 15 a first planetary gear 41 and for every other planetary gear 16 a second planetary gear 42 on. The planetary gear shots 41 . 42 are as straight, cylindrical free spaces in the housing body 28 , in particular in the differential web section 35 formed and extend parallel to the main axis of rotation H , It should be noted that an angle of wrap in the direction of rotation about the axis of rotation of the first planet gears 15 in the first planetary gear shots 41 greater than 180 degrees, in particular greater than 200 degrees, so that the first planet gears 15 are secured positively in the radial direction. In contrast, a wrap angle of the second Planetenradaufnahmen 42 for the second planet gears 16 in the direction of rotation about their axes of rotation less than 180 degrees, in this example about 120 degrees.

As already explained at the beginning, the small angles of wrap, in particular for the second planetary gears 16 no difficulty, because at a load of the differential device 10 the planet wheels 15 . 16 be pressed radially outwards, so that these guide surfaces 32 abut by the first and second Planetenradaufnahmen 41 . 42 are formed, and are guided by the head.

As can be seen in particular from the 3 gives, are the first and second planet gears 15 . 16 as well as the first and the second sun gear 11 . 12 equipped with a spur toothing, wherein the pairs of teeth to the main axis of rotation H extend.

The first and second sun wheels 11 . 12 each have a thrust axle 45 . 46 on, in which the first and second output shaft 13 . 14 can be inserted.

In the 5 is the compact design of the gearbox section 6 can be seen again, in addition to see that the first planetary gears 15 with its gearing width both over the gearing width of the first sun gear 11 with which they are engaged, and the gearing width of the second planet gears 16 and the second sun gear 12 extend in the axial direction. Thus, the differential device 10 especially narrow in the axial direction.

The entrance planet wheels 19 , in particular their teeth, are designed in the axial width significantly narrower than the Lastplanetenräder 23 or their teeth. The entrance planet wheels 19 as well as the load planet wheels 23 wear the same helical gearing in the same orientation. The crack overlap of the input planet wheels 19 , the load planetary wheels 23 , the input sun gear 18 and the load sun gear 22 are each executed in integer. The jump overlaps between the planetary gearbox 8th and the planetary gear stage 9 However, they have a difference of exactly or at least 1 on. The transmission section 6 is formed in the described manner so compact that it remains in the sectional view shown within a DIN A4 sheet.

LIST OF REFERENCE NUMBERS

1

electric drive

2

vehicle

3

axis

4

bikes

5

electric motor

6

gear section

7a, b

outputs

8th

Planet input transmission stage

9

Planetary powershift stage

10

differential device

11

first sun gear

12

second sun wheel

13

first output shaft

14

second output shaft

15

first planet wheels

16

second planet wheels

17

rotor shaft

18

input sun

19

Input planet gears

20

Input planet carrier

21

Eingangshohlradabschnitt

22

Lastsonnenrad

23

Last planetary gears

24

Planet carrier device

25

Lasthohlradabschnitt

26

sprocket

27

casing

28

Housing body

29

Pipe-shaped housing sleeve

30

Optional end cover

31

bolt

32

guide surfaces

33

bolt

34

Last web portion

35

Differential web portion

36

ring section

37

web

38

window

39

bolt Hole

40

Continuous internal toothing

41

First planetary gear

42

Second planetary gear

43

First guide plate

44

Second guide plate

45

First thru axle mount

46

Second thru axle mount

D1

first pitch diameter

D2

second pitch diameter

D3

third pitch circle diameter

D4

fourth pitch diameter

H

Main axis of rotation

VB1

first tooth width

VB2

second gearing width

VB3

third gearing width

VZ 1

first gearing level

VZ 2

second gearing level

Claims (10)

Electric drive (1) for a vehicle (2) with an electric motor (5), with two outputs (7a, b) for outputting a drive torque, with a transmission portion (6) for transferring the drive torque from the electric motor (5) to the two outputs (7a, b) of the electric drive (1), wherein the transmission portion (6) comprises a differential device (10), wherein the differential device (10) has a first and a second sun gear (11,12) and a set of first planetary gears (15) and a set of second planet gears (16), the sun gears (11, 12) defining a main axis of rotation (H) of the gear section (6), the sun gears (11, 12) being operatively connected to the outputs (7a, b), wherein the first planet gears (15) mesh with the first sun gear (11) and the second planet gears (16) with the second sun gear (12), a first planet gear (15) each having two second planetary gears (16) and a second planetary gear (16). 16) with two e meshing with the planetary gears (15), so that a toothed rim (26) which is continuous in the direction of rotation about the main axis of rotation (H) is formed by first and second planetary gears (15, 16), wherein the first and the second planet gears (15,16) each have the same number of teeth and wherein the first and the second sun gear (11,12) each have the same number of teeth, characterized in that the first planetary gears (15) formed as a long planet gears are, which extend in the axial direction to the main axis of rotation (H) at least partially over the second sun gear (12), wherein the second sun gear (12) compared to the first sun gear (11) has a smaller tip diameter. Electric drive (1) after Claim 1 , characterized in that the toothings of the first and the second sun gear (11,12) are profile-shifted from each other. Electric drive (1) after Claim 1 or 2 , characterized in that the first planet gears (15), the second planet gears (16), the first sun gear (11) and / or the second sun gear (12) have a straight toothing. Electric drive (1) according to one of the preceding claims, characterized in that the first and / or the second planet gears (15,16) are guided by a head circle. Electric drive (1) according to one of the preceding claims, characterized in that the sum of the first and the second planet gears (15,16) is greater than or equal to ten. Electric drive (1) according to one of the preceding claims, characterized in that the electric motor (5) is arranged coaxially to the main axis (H). Electric drive (1) after Claim 6 characterized in that the gear portion (6) comprises a planetary gear stage (9), the planetary gear stage (9) being interposed between the electric motor (5) and the differential means (10), one of the outputs (7a, b) being coaxial through at least one planetary gear stage (9) and the electric motor (5) is guided. Electric drive (1) according to one of the preceding Claims 6 or 7 , characterized in that the differential device (10) and the planetary gear stage (9) have a common planet carrier device (24). Electric drive (1) according to one of the preceding Claims 6 to 8th , characterized in that the transmission portion (6) comprises a planetary input gear stage (8), wherein the planetary input gear stage (8) between the planetary gear stage (9) and the electric motor (5) is arranged. Vehicle (2) with the electric drive (1) according to one of the preceding claims.

Images