CN108136896B

CN108136896B - Transmission device and electric drive unit having a transmission device

Info

Publication number: CN108136896B
Application number: CN201580083709.5A
Authority: CN
Inventors: 托斯滕·迈尔赫费尔; 托斯滕·比尔曼; 菲利普·武尔茨贝格尔; 菲利普·斯特纳
Original assignee: Schaeffler Technologies AG and Co KG
Current assignee: Schaeffler Technologies AG and Co KG
Priority date: 2015-10-13
Filing date: 2015-11-17
Publication date: 2021-03-05
Anticipated expiration: 2035-11-17
Also published as: CN108136896A; WO2017063621A1; DE102015222616B4; DE102015222616A1

Abstract

The invention relates to a transmission device having at least an input, an input stage, a load stage, a carrier and at least two output shafts, wherein: the input shaft is a first sun wheel which is rotatable about a central axis of the transmission, the input stage has a first sun wheel and a first planet wheel which is radially spaced from the central axis, the first sun wheel and the first planet wheel are coupled to one another via a first transmission connection, the load stage is formed by second planet wheels and a ring gear, one of the first planet wheels and one of the second planet wheels are each carried by a carrier in a rotationally fixed manner to one another and rotatable about a common first planet axis which is radially spaced from the central axis, the ring gear is held azimuthally fixed on the transmission housing and forms a first tooth mesh with the second planet wheel, the axis of symmetry of the ring gear is the central axis, the carrier is connected rotationally fixed to a differential cage of the transfer case, the carrier is rotatable in the transmission housing about the central axis relative to the input shaft, and-the carrier is coupled with the output shaft via a second gearing action connection of the transfer case. The invention also relates to an electric drive unit having a transmission device of this type.

Description

Transmission device and electric drive unit having a transmission device

Technical Field

The invention relates to a transmission device having at least an input, an input stage, a load stage, a carrier and at least two output shafts, wherein:

the input shaft is a first sun wheel rotatable about a central axis of the transmission,

the input stage has a first sun wheel and a first planet wheel radially spaced from the central axis,

-the first sun wheel and the first planet wheel are coupled to each other via a first transmission action with a connection (Wirkvertandung),

the load stage is formed by the second planet wheels and the ring gear,

one of the first planet wheels and one of the second planet wheels are each carried by the carrier in a rotationally fixed (rotational) connection with each other and rotatable about a common first planet axis radially spaced from the central axis,

the ring gear is held fixed in position on the gear housing and forms a first toothing with the second planetary gear, the axis of symmetry of the ring gear being the central axis,

the carrier is connected in a rotationally fixed manner to a differential cage of the transfer case,

the carrier is rotatable in the gear housing in a manner rotatable about a central axis relative to the input shaft, and

the carrier is coupled to the output shaft via a second transmission action connection of the transfer case.

The invention also relates to an electric drive unit having a transmission device of this type.

Background

US 6401850B 1 shows an electric drive unit of this type. These electric drive units are often used as modules for driving axles in electric vehicles or in all-wheel-drive hybrid vehicles. The transmission is equipped with a reduction stage and a differential. The reduction stage is characterized by a planetary gear set with a double planetary gear set. The sun gear of the planetary gear is connected to the rotor shaft of the electric motor and forms a toothed engagement with the first planetary gear set of the double planetary gear. The second planetary gear set of the double planetary mechanism is in tooth engagement with the ring gear. The ring gear is fixed to a housing of the drive unit. The planet carrier is connected to a differential cage of the differential, which planet carrier carries the double planet in a rotatable manner. The differential is a bevel gear differential, the driven wheel of which is connected to the driven shaft via a plug-in shaft. Wherein each driven shaft is operatively connected to a driven wheel of a driven axle.

Disclosure of Invention

The object of the present invention is to provide a transmission device and an electric drive unit which can be configured variably in terms of transmission ratio and which can be implemented compactly.

According to the invention, the first transfer connection has at least one third planetary gear integrated into the input stage.

The present invention relates to a transmission device into which a transfer gear is integrated. The transfer case is longitudinally or transversely installed in the vehicle. The transmission device is preferably applied to an electrically driven vehicle or a hybrid vehicle. The electric motor and the transmission are accommodated in a housing. The rotor shaft has an axis of rotation on the central shaft and is connected to the input shaft of the transmission.

The characteristics of an electromotive drive are essentially determined by the coordination of the transmission ratio with the characteristic curve set of the electric motor that drives. This is particularly difficult when the transmission has only fixed transmission ratios. Important characteristics are hill climbing capability, acceleration, efficiency (energy consumption) and maximum achievable vehicle speed. All these characteristics cannot be optimally met when selecting the transmission ratio. The optimal gear ratio for maximum hill climbing capability of the vehicle is usually different from the required value for maximum final speed or energy efficiency. Optimization of the transmission ratio is therefore of paramount importance. Furthermore, these requirements may also differ depending on the type of vehicle in which the drive unit is used. The vehicle type is for example a city vehicle, a mini, mini or compact car, an SUV or the like. The constraints in the design of the gear mechanism due to the narrow installation space and the design of the gearing are often the opposite of the above-mentioned requirements. By means of the invention, more design and variation possibilities are provided in the narrowest construction space than hitherto known from the prior art. Instead of one planetary gear set, the transmission ratio of the input stage can be adapted to different vehicle requirements by a combination of two planetary gear sets. The fixed-axis transmission ratio and the final transmission ratio (End ü bersetzeng) can be designed more differently.

The third planet gears are each (as are the other planet gears) carried by the carrier in a manner rotatable about a planet axis radially spaced from the central axis. The third planet wheel is double-engaged and for this purpose simultaneously forms a tooth engagement with the first sun wheel and the first planet wheel. The first planetary gear is a double planetary mechanism. The additional group of planet gears is therefore arranged in the input stage in the power flow between the sun gear, which acts as the power input of the transmission, and the double planetary gear. Furthermore, it is provided that the toothing of the first planet wheel has more teeth than the toothing of each second planet wheel. The teeth of each second planet have more teeth than the teeth of the third planet. With an arrangement of this type, in particular in drive units whose electric motor rotates at high speeds of 12000 to 16000 rpm, a total transmission ratio of 6 to 8 can be achieved over the narrowest construction space. The invention is accordingly provided with an electric drive unit having a transmission device according to the invention as a connection for a first transmission action.

The second drive-action connection of the transmission device, i.e. the transfer case, can be embodied as a bevel gear differential or in any other way. The invention provides that the transfer case is a planetary differential and has a wheel set with a fourth planet wheel, a wheel set with a fifth planet wheel, a second sun wheel and a third sun wheel. The third sun gear is arranged coaxially with the second sun gear on the central axis. Each fourth planet gear forms a fourth tooth mesh with the second sun gear and each fourth planet gear forms a fifth tooth mesh with the fifth planet gear. The fourth planet is approximately as wide as the second sun gear. The fifth planetary gear is at least twice as wide in the axial direction as the fourth planetary gear, so that the fifth planetary gear meshes with the third sun gear to form a sixth tooth. The fourth planet wheel is therefore also referred to as a short planet wheel and the wider planet wheel as a long planet wheel. The second sun gear is operatively connected to a first of the two output shafts, and the third sun gear is operatively connected to a second of the two output shafts.

In the transfer case, the number of teeth of the toothing of the planet wheels and the axial distance between the planet axis of the planet wheels and the intermediate shaft can be different from one another or identical in the individual planetary wheel sets. The number of teeth of the sun gear of the transfer gear may be the same or different from each other. A transfer gear is understood to mean, in the sense of the invention, the following transmission: in this case, the power introduced is distributed in a constant proportion to two output shafts, for example two driven axles, during straight travel. Alternatively, the transfer case is the following differential of the axle in the sense of the invention: in this case, the torque is shared equally between the two output shafts during straight travel without slip between the two output shafts.

The design of the invention is based on the fact that the differential of the axle has the same number of sun gears and the two planetary gear sets of the planetary differential also have the same toothing. With this embodiment, it is advantageously possible to provide the same drive behavior in the vicinity of the wheels in a narrow installation space to the left and to the right of the axle.

The available axial installation space between the wheels of the driven axle is dimensioned for the size of the coaxially arranged transmission with planetary stages. Which are typically narrowly sized. The design of the invention therefore provides that the planet wheels of the double planetary gear set, which mesh with the ring gear, and the planet wheels of the two planetary gear sets of the transfer case and the sun gear are all arranged radially within the ring gear, which is designed as a ring gear. In this case, the planet wheels of one of the planetary wheel sets can partially project axially from the ring gear. The toothing of the planet wheels with the ring gear, the toothing of the planet wheels of the planetary transfer gear with one another and the toothing of a group of planet wheels with the sun gear of the transfer gear are located in one tooth plane. The tooth plane is an imaginary radial plane that perpendicularly intersects the central axis. By such a radial mutual nesting of the two planetary stages, the installation space required in the axial direction is kept approximately the same size or smaller in comparison with the known prior art despite the additional planetary stages.

In an embodiment of the invention, the planet wheels of the double planetary gear set that are in toothed engagement with the ring gear each at least partially sink radially into a circumferential gap between the planet wheels spaced apart from one another on the circumferential side of one or both wheel sets of the transfer case. The installation space required in the radial direction can thereby also be kept advantageously small.

In the transmission connection, the teeth of the gears mate with one another in a form-locking manner for the purpose of transmitting a rotational movement via the teeth. Starting from the ideal situation in which the tooth with the highest load is loaded over its entire tooth width in the tooth engagement, for example in the case of a spur gear, the average tooth engagement extends over half the axial width of the tooth centers, i.e. the teeth which form a tooth engagement with one another. Co-located in one tooth plane means that the average tooth engagement is co-located in a radial plane that perpendicularly intersects the rotational axis of the gear. This also applies to double-occupied or multi-occupied gears, i.e. to gears which simultaneously form a toothed engagement with more than two gears. In this case, the two or more average tooth engagements lie in a common tooth plane. Thus, for example, the sun wheel is always occupied multiply by a set of planet wheels. Further examples form the short planet wheels of the transfer case described above. Furthermore, the tooth engagements of any number of gear pairs may lie in a common tooth plane, even if the gear pairs do not come into tooth contact with each other. In this case, it is to be ignored that the tooth centers of the teeth which lie in one tooth plane but do not form a common tooth engagement may be slightly offset from one another in the axial direction due to tolerances. It is also not important here whether the tooth widths of the gears lying in one tooth plane differ.

Two types of double-occupied or multi-occupied gears are obtained. One type has the features of the previously described gear with two or more average tooth engagements in one tooth plane. Another type of double occupied gear is formed by a spur gear meshing with two or more gear teeth, in which the average tooth meshes are staggered from each other in the axial direction, i.e. in the direction along the axis of rotation of the gear. Accordingly, the average tooth engagement, although on one gear wheel, is still in the axially adjacent tooth planes. In this context, it is assumed that the teeth have the same tooth geometry in the axial direction in the case of a double-occupied gear. The latter distinguishes the gear from a stepped planetary mechanism or a double planetary mechanism. An example for such double-engaged gears is the short planet gears of the transfer case, which simultaneously form a toothing with the sun gear and respectively with the long planet gears of the other planetary gear set in one tooth plane. The long planet is a special case of a double planetary mechanism because it is in tooth engagement with the short planet in one tooth plane and with the sun in an adjacent tooth plane, i.e. it can be formed by two gears with identical or different teeth.

The carrier is preferably formed by a single carrier section or housing part and is thus simultaneously a planet carrier and a differential cage. This advantageously enables a cost-effective and space-saving design.

Drawings

The invention is illustrated in detail below with the aid of examples. Wherein:

fig. 1 shows a simplified and not dimensionally represented structure of an electric drive unit 1;

fig. 2 shows an embodiment of the transmission device 2 applied in the drive unit 1 in an overall view with a partial sectional view through the planet carrier 3;

fig. 3 shows an exploded view of the transmission 2;

fig. 4 shows a front view of the interior of the transmission device 2 without the side plates of the bracket;

fig. 5 shows a simplified and schematic representation of the gears of the gear device 2 in a view from the rear side of the representation shown in fig. 4.

Detailed Description

FIG. 1: the electric drive unit 1 is composed of an electric motor 4, a gear mechanism 2 and a housing 14. The motor 4 and the transmission 2 are accommodated in a housing 14. The rotor shaft 5a of the rotor 5 of the electric machine is connected to the input of the gear unit 2. The input end of the drive shaft is a sun gear S1, which is mounted on an axial extension of the rotor shaft 5 a. The output of the transmission is two output shafts a1 and a 2. The output shaft a1 is coupled with the transfer case sun gear S2 and the output shaft a2 is coupled with the sun gear S3. The rotor shaft 5a is a hollow shaft through which the first output shaft a1 passes in the axial direction. Further, the first output shaft a1 passes through the first sun gear S1. The gear unit 2 is divided into an input stage ES and a load stage LS and a transfer gear VG. An important component of the input stage ES, the load stage LS and the transfer gear VG is the carrier 3 with a carrier plate 3a, a differential cage 3b and a carrier plate 3 c. The carrier 3 is mounted in the housing 5 so as to be rotatable about a central axis 10.

Fig. 1 and 3: the first transfer connection described by the input stage ES has a carrier plate 3a, two sets of planet wheels P1 and P3 and a first sun wheel S1. The first planet wheel P1 and the second planet wheel P2 are each part of a double planetary arrangement DP of a set of double planetary arrangements DP. The load stage LS is formed by the wheel set of the second planetary wheels P2 and the ring gear H. The transfer gear VG has a differential cage 3b and a carrier plate 3c and a drive-active connection formed by the wheel set of the second sun wheel S2, the third sun wheel S3, the fourth planet wheel P4 and the fifth planet wheel P5. The sun gears S1, S2, and S3 are located on the central axis 10 in a rotatable manner relative to each other.

FIG. 3: the planet wheels P1 and P2 are combined to a double planetary DP and have a common planet axis 6. The planet wheels P3, P4 and P5 are rotatable about the planet axis 7, 8 or 9 on the planet pin 11, 12 or 13 and are mounted at a radial distance from the central axis 10.

Fig. 1, 2, 4 and 5: the second planet wheels P2 form a first tooth mesh ZE1 with the ring gear H. The first sun wheel S1 forms a second tooth mesh ZE2 with the third planet wheels P3 in a first tooth plane VE1 (fig. 1), wherein each third planet wheel P3 simultaneously forms a third tooth mesh ZE3 with the first planet wheel P1 in the same tooth plane VE 1. In the tooth plane VE2, the ring gear H forms a tooth mesh ZE1, ZE4 or ZE5 with the second planetary gear P2, the short fourth planetary gear P4 with the second sun gear S2 and the short fourth planetary gear P4 with in each case one fifth planetary gear P5. The second planetary wheel P2, the fourth planetary wheel P4, and the second sun wheel S2 are arranged radially within the ring gear H embodied as a ring gear, i.e., are surrounded by the ring gear. The ring gear H is fastened to the housing 5. The long fifth planetary gears P5 are double-engaged and form, in addition to the tooth meshes ZE5, a sixth tooth mesh ZE6 with the third sun gear S3 (see fig. 1 and 5), respectively. Each of the second planet wheels P2 is radially immersed in a recess between a fourth planet wheel P5 and a fifth planet wheel P5, which are spaced apart from one another on the circumferential side.

List of reference numerals

Claims

1. Transmission device (2) having at least an input (E), an input stage (ES), a Load Stage (LS), a transfer gear (VG), a carrier (3) and at least two output shafts (A1, A2), wherein:

-the input end (E) is a first sun wheel (S1) rotatable about a central axis (10) of the transmission device (2),

-the input stage (ES) has the first sun wheel (S1) and a first planet wheel (P1) radially spaced from the central axis (10),

-the first sun wheel (S1) and the first planet wheel (P1) are coupled to each other via a first transmission connection,

-the Load Stage (LS) is formed by a second planet wheel (P2) and a ring gear (H), the second planet wheel (P2) forming a first tooth mesh (ZE1) with the ring gear (H),

-one of the first planet wheels (P1) and one of the second planet wheels (P2) are each carried by the carrier (3) in a rotationally fixed connection with each other and rotatable about a common planet axis radially spaced from the central axis (10),

-the ring gear (H) is held fixed in position and forms a first tooth mesh with a second planetary mechanism (P2), the axis of symmetry of the ring gear being the central axis (10),

the carrier (3) is connected in a rotationally fixed manner to a differential cage (3b) of the transfer case (VG),

-the stand (3) is rotatable around the central axis (10) with respect to a first sun gear (S1),

and the carrier (3) is coupled with the output shaft (A1, A2) via a second gearing connection of the transfer gear (VG),

characterized in that the first transfer connection has at least one third planet (P3) integrated into the input stage,

a fourth tooth engagement (ZE4) between a second sun gear (S2) and a fourth planet gear (P4) in a second gearing connection; and a fifth tooth engagement (ZE5) between each of the second, operatively connected fourth planetary gears (P4) and the doubly engaged fifth planetary gear (P5), wherein the first tooth engagement (ZE1), the fourth tooth engagement (ZE4) and the fifth tooth engagement (ZE5) lie in a common second tooth surface plane (VE 2).

2. Transmission according to claim 1, characterized in that said third planet gears (P3) are carried by said carrier (3) in a manner rotatable about a second planet axis (7) radially spaced from the central axis (10) and form a second tooth mesh (ZE2) with said first sun gear (S1), and each third planet gear (P3) forms a third tooth mesh (ZE3) with a respective one of the first planet gears (P1).

3. The transmission arrangement according to claim 1, characterized in that the second transmission operative connection is formed by a fourth planet wheel (P4), a fifth planet wheel (P5), a second sun wheel (S2) and a third sun wheel (S3), wherein the third sun wheel (S3) is arranged coaxially with the second sun wheel (S2) on the central axis (10), the third sun wheel (S3) forms a sixth tooth engagement (ZE6) with the fifth planet wheel (P5), and wherein the second sun wheel (S2) is operatively connected to a first output shaft (a1) of the two output shafts (a1, a2), and the third sun wheel (S3) is operatively connected to a second output shaft (a2) of the two output shafts (a1, a 2).

4. Transmission according to claim 3, characterized in that not only the second planet wheels (P2), but also the fourth planet wheel (P4), the second sun wheel (S2), the fourth tooth engagement (ZE4) and the fifth tooth engagement (ZE5) are arranged radially between the central axis (10) and the ring gear (H).

5. The transmission apparatus of claim 3, wherein: having a second tooth engagement (ZE2) and a third tooth engagement (ZE3) which are located together in a first tooth plane (VE 1); and a sixth tooth engagement (ZE6) in a third tooth plane (VE3), wherein the individual tooth planes (VE1, VE2, VE3) are in each case imaginary radial planes which intersect perpendicularly with the central axis (10).

6. Transmission according to claim 3, characterized in that said fourth planet (P4) is carried on said carrier (3) in a rotatable manner about a third planet axis (8), said fifth planet (P5) being carried on said carrier (3) in a rotatable manner about a fourth planet axis (9).

7. An electric drive unit (1) having at least: a housing (5); an electric machine (4) arranged in the housing (5) and having a rotor shaft (5a) and a transmission (2) according to the preamble of claim 1, wherein the electric machine (4) and the transmission (2) are accommodated in the housing (5), wherein the rotor shaft (5a) has an axis of rotation on the central axis (10) and is connected to the first sun wheel (S1), characterized in that the first transmission connection has a third planet wheel (P3) integrated into the input stage (ES), wherein the third planet wheel (P3) in a first tooth plane (VE1) forms a tooth engagement with the first sun wheel (S1) and with the first planet wheel (P1), respectively, and has a fourth tooth engagement (ZE4) between a second sun wheel (S2) and a fourth planet wheel (P4) which are connected in a second transmission; and a fifth tooth engagement (ZE5) between each of the second, operatively connected fourth planetary gears (P4) and the doubly engaged fifth planetary gear (P5), wherein the first tooth engagement (ZE1), the fourth tooth engagement (ZE4) and the fifth tooth engagement (ZE5) lie in a common second tooth surface plane (VE 2).

8. An electric drive unit as set forth in claim 7, characterized in that: wherein the fourth planet wheel (P4) is mounted on the carrier (3) so as to be rotatable about the third planet axis (8), and the fifth planet wheel (P5) is mounted on the carrier (3) so as to be rotatable about the fourth planet axis (9).

9. The electric drive unit according to claim 8, characterized in that each fifth planet (P5) is double-engaged by the fourth tooth mesh (ZE4) and by a sixth tooth mesh (ZE6) with a third sun gear (S3), wherein the second sun gear (S2) and the third sun gear (S3) are arranged coaxially to each other, and wherein the second sun gear (S2) is operatively connected to a first output shaft (A1) of the two output shafts (A1, A2) and the third sun gear (S3) is operatively connected to a second output shaft (A2) of the two output shafts (A1, A2).

10. The electric drive unit of claim 8, wherein each second planet wheel (P2) at least partially sinks radially into a gap between fourth planet wheels (P4) that are spaced apart from one another on the circumferential side.