DE102019003159B3 - Electric drive train - Google Patents

Abstract

Electric drive train (10) for a motor vehicle
- with an electric machine (12, 112) having a stator (14) and a rotor (16), wherein the rotor (16) rotatably connected to a rotor shaft (18) and a Rotorabtriebszahnrad (20),
with a differential gear (52) having a differential input gear (54),
- comprising a planetary gear (26) having a planetary gear set with a first differential shaft (28), a second differential shaft (30), a sum shaft (32), a brake element (36) and a Verblockungsschaltelement (40), wherein the brake element (36 ) is configured to non-rotatably connect the second differential shaft (30) to a housing (38),
- With a first countershaft (22) which is arranged coaxially to the single planetary set and parallel to the rotor shaft (18), and which is non-rotatably connected to the sum shaft (32),
- With a first driven gear (48) which is rotatably connected to the first countershaft (22) and which permanently meshes with the differential input gear (54),
wherein the rotor output gear (20) is permanently engaged with a planetary gear input gear (34) non-rotatably connected to the first differential shaft (28).

Description

The invention relates to an electric drive train according to the preamble of patent claim 1.

Such an electric drive train is already known from the generic document DE 10 2015 016 939 known. Electric drive trains with a switchable planetary gear and a multi-stage countershaft transmission are also from the EP 0 069 506 A2 , of the DE 103 22 234 A1 and the US 4,788,887 A. known.

The object of the present invention is to present an electric drive train which at the same time offers an improved switching behavior that can be experienced by a customer, an improved overall efficiency and nevertheless the highest possible degree of compactness.

This object is achieved by an electric drive train with the features of claim 1.

It is assumed that an electric drive train for a motor vehicle, which has an electric machine, which in turn has a stator and a rotor, wherein the rotor is rotatably connected to a rotor shaft and a rotor output gear.
Furthermore, the electric drive train has a differential gear, which has a differential input gear, and a planetary gear.
The planetary gear in turn has a planetary gear set with a first differential shaft, a second differential shaft, a sum shaft, a brake element and a Verblockungsschaltelement, wherein the brake element is adapted to rotatably connect the second differential shaft with a housing.
It is further assumed that the electric drive train has a first countershaft, which is arranged coaxially to the simple planetary set and parallel to the rotor shaft, and which is non-rotatably connected to the sum shaft.

A first output gear is rotatably connected to the first countershaft, and the first output gear meshes permanently with the differential input gear. In this case, the rotor output gear is permanently engaged with a planetary gear input gear rotatably connected to the first differential shaft.

According to the invention, a second countershaft is provided, which is arranged parallel to the rotor shaft and parallel to the first countershaft, wherein a second output gear is rotatably connected to the second countershaft. The second output gear is according to the invention permanently in engagement with the differential input gear.
Further, according to the invention, a gear wheel arranged coaxially with the second countershaft is provided which is permanently engaged with the rotor driven gear.

Advantageously, the electric machine is designed as an internal rotor, which means that the rotor is arranged radially inside the stator.

The differential gear can be designed as a ball differential or as a planetary differential. Advantageously, the differential gear is designed as a ball differential, wherein advantageously the differential input gear is rotatably connected to a differential cage.

Under a rotationally fixed connection of two rotatably mounted elements is to be understood in the context of the invention that the two elements are arranged coaxially with each other and connected to each other so that they rotate at the same angular velocity. Under a rotationally fixed connection of an element with a housing is to be understood that the element is so connected to the housing that it can not be rotated relative to the housing.

By a gear wheel is meant a gear for forming a gear.

By the term that two gears are engaged with each other, it is meant that the two gears are arranged so that their respective teeth are permanently meshed with each other.

Advantageously, the first output gear, the second output gear and the differential input gear are arranged in a common first gear plane.

Further advantageously, the rotor output gear, the planetary gear input gear and the gear wheel are arranged in a common second gear plane.

With a gear plane of a gear is meant a plane which is arranged perpendicular to a rotational axis of the gear and which is arranged within an axial extent of a toothing of the gear. By a common gear plane of a plurality of gear wheels is meant a plane which is perpendicular to the axes of rotation of the gears angeordent - wherein gears of a common gear plane always have parallel axes of rotation, and which is located within axial extensions of the gears of the gears.

An advantageous development of the invention provides that the first countershaft and the second countershaft are each formed as a solid shaft. In this case, particularly advantageously, the electric machine, the first gear plane, the second gear plane and the planetary gear are arranged in succession in the order indicated in an axial direction.

In the context of the invention, the axial direction means the direction of an axis of rotation of the rotor shaft, wherein the rotor shaft is arranged parallel to the countershafts or their axes of rotation.

Alternatively, a further advantageous embodiment of the invention provides that the first countershaft and the second countershaft are each formed as a hollow shaft. In this case, particularly advantageously, the electric machine, the second gear plane, the first gear plane and the planetary gear are arranged in succession in the order indicated in an axial direction.

With the two alternatives, an axially compact drive train can be realized.

Further advantageously, the Verblockungsschaltelement along the first countershaft seen on a side facing away from the electric machine of the planetary gear is arranged. This allows the Verblockungsschaltelement and an associated Aktuierungsvorrichtung realize cost-effective and space-saving.

Further advantageously, the braking element is seen along the first countershaft facing away on a side facing away from the electric machine of the Planetensatzeingangszahnrads, whereby the brake element and an associated further Aktuierungsvorrichtung realize cost-effective and space-saving.

A further advantageous embodiment of the invention provides a frictional switching element, which is arranged coaxially to the second countershaft and which is adapted to rotatably connect the gear wheel with the second output gear. At first glance, such a switching element for a gear wheel of a countershaft seems to mean an unnecessary effort. However, it has been found that the effort in exactly this powertrain concept worthwhile at exactly this point to represent a load shiftability of the gears can.
Particularly advantageous is the frictional engagement element along the second countershaft seen on a side remote from the electric machine side of the second output gear and on a side facing away from the electric machine of the gear wheel ( 60 ) is arranged. Particularly advantageously, the frictional switching element is arranged at least partially axially overlapping to the planetary gear.

Particularly advantageously, the braking element is designed positively. Normally, brake elements of planetary gears are frictionally engaged. However, it has been found in the drive train concept according to the invention that a good switchability is ensured even if a low-cost and low-friction positive locking brake element is used.

It is particularly advantageous, in the case of the formation of first and second countershaft each as a solid shaft, the planetary gear input gear rotatably connected to a ring gear of the planetary gear, wherein the second differential shaft is rotatably connected to a sun gear of the planetary gear. This can advantageously be realized by means of the planetary gear, a large leap.

Alternatively and also advantageous, in the case of the formation of first and second countershaft each as a hollow shaft, the planetary gear input gear rotatably formed with a sun gear of the planetary gear, wherein the second differential shaft is rotatably connected to a ring gear of the planetary gear.

In the following the invention will be described by way of example with reference to the accompanying drawings.

• - 1 eine schematische Darstellung eines ersten Ausführungsbeispiels eines erfindungsgemäßen elektrischen Antriebsstranges,
• - 2 eine schematische Darstellung eines zweiten Ausführungsbeispiels des erfindungsgemäßen elektrischen Antriebsstranges.

Show

• - 1 a schematic representation of a first embodiment of an electric drive train according to the invention,
• - 2 a schematic representation of a second embodiment of the electric drive train according to the invention.

In the in 1 shown first embodiment has an electric drive train 10 an electric machine 12 which in turn has a stator 14 , a rotor 16 and one rotatably with the rotor 16 connected rotor shaft 18 having.
The electric drive train 10 also has a three-speed transmission 19 on.

The three-speed gearbox 19 has a rotor output gear 20 on which with the rotor shaft 18 rotatably connected. By means of the rotor output gear 20 can torque in the three-speed gearbox 19 be initiated.

The three-speed gearbox 19 further includes a full wave trained first countershaft 22 and a likewise designed as a solid shaft second countershaft 24 on.

Coaxial to the first countershaft 22 is a planetary gear 26 of the three-speed gearbox 19 arranged.

The planetary gear 26 has a planetary gear input gear 34 on, which rotatably with a first differential shaft 28 of the planetary gear 26 connected is. By means of planetary gear input gear 34 are torques in the planetary gear 26 initiated. A toothing of planetary gear input gear 34 is permanently with a toothing of the rotor output gear 20 engaged. In the first embodiment, the planetary gear is 26 designed as a simple planetary set, wherein a ring gear 46 of the planetary gear rotatably with the first differential shaft 28 connected, a sun gear 42 non-rotatable with a second differential shaft 30 is connected and a planet carrier 44 non-rotatable with a total shaft 32 of the planetary gear 26 connected is. The planet carrier 44 is designed as a simple planet carrier.

By means of the sum wave 32 of the planetary gear 26 are torques from the planetary gear 26 discharged. The sum wave 32 is non-rotatable with a first output gear 48 of the three-speed gearbox 19 connected. The sum wave 32 is designed as a solid shaft and rotationally fixed to the first countershaft 22 connected. The sum wave 32 represents a first output shaft.

The planetary gear 26 has a brake element 36 and a blocking switching element 40 on, whereby two shiftable gear stages by means of the planetary gear 26 can be switched. The brake element 36 is designed to be the second differential shaft 30 or the sun wheel 42 rotatably with a housing 38 connect to.

The brake element 36 is inexpensive and friction low as a positive switching element, for example, as a claw switching element formed. Also the blocking switching element 40 is inexpensive and friction low as a positive switching element, for example, as a claw switching element formed.

Coaxial to the second countershaft 24 is a gear wheel 60 arranged, which rotatably with the second countershaft 24 connected is. A gearing of the gear wheel 60 is permanently connected to the toothing of the rotor output gear 20 engaged.

Also coaxial with the second countershaft 24 is a second output shaft 51 arranged. The second output shaft 51 is non-rotatable with the second countershaft 24 connected. The second output shaft 51 is non-rotatable with a second output gear 50 connected.

A frictional switching element 62 is intended to the second output gear 50 rotatably with the gear wheel 60 connect to. The frictional switching element 62 is advantageous coaxial with the second countershaft 24 arranged and is preferably designed as a multi-plate clutch.

The second countershaft 24 , the gear wheel 60 , the frictional switching element 62 and the second output gear 50 are elements of a sub-transmission 63 , by means of which a third shiftable gear can be formed. Advantageously, the three-speed transmission 19 be designed so that a translation of the shiftable gear stage of the sub-transmission 63 either smaller or larger than the ratios of the two shiftable gears of the planetary gear 26 ,

Both the first output gear 48 as well as the second output gear 50 mesh permanently with a differential input gear 54 a differential gear 52 , The first output gear 48 , the second output gear 50 and the differential input gear 54 are in a common first wheel plane 66 arranged.

The rotor output gear 20 , the planetary gearset gear 34 as well as the gear wheel 60 are in a common second wheel plane 68 arranged.

In an axial direction 64 seen are the electric machine 12 , the first wheel plane 66 , the second wheel plane 68 , the sun wheel 42 and the blocking switching element 40 arranged one after the other in the order named.

In the axial direction 64 seen is the frictional switching element 62 on one of the electric machine 12 opposite side of the second wheel plane 68 arranged.

The differential gear 52 has a rotationally fixed with the differential input gear 54 connected differential cage 56 on. The differential cage 56 is advantageous in the axial direction 64 seen between the electric machine 12 and the planetary gear 26 arranged.

In addition, the differential gear has 52 sideshafts 58 on which parallel to the rotor shaft 18 are arranged.

2 shows a further embodiment of an electric drive train 110 with a three-speed gearbox 119 in which a first countershaft 122 and a second countershaft 124 are designed as full waves. A planetary gear input gear 134 is coaxial with the first countershaft 122 arranged and rotatable with a sun gear 142 a planetary gear 126 connected.

In the embodiment of 2 is a first difference wave 128 of the planetary gear 126 rotatably with the sun gear 142 connected. A second differential shaft 130 is non-rotatable with a ring gear 146 connected. A brake element 136 is designed to the ring gear 146 with a housing 138 connect to.

In the embodiment of the 2 are an electrical machine 112 , a second wheel plane 168 , a first wheel plane 166 and a planetary gear 126 in an axial direction 164 seen arranged in succession in the order named. Here are a Rotorabtriebszahnrad 120 , the planetary gearset gear 134 as well as a gear wheel 160 in the common second wheel plane 168 arranged. And there are a first output gear 148 , a second output gear 150 and a differential input gear 154 in the common first wheel plane 166 arranged.

Advantageously, the three-speed transmission 119 be designed so that a translation of the shiftable gear stage of a sub-transmission 163 between translations of two shiftable gears of the planetary gear 126 lies.

LIST OF REFERENCE NUMBERS

10, 110

Electric drive train

12, 112

Electric machine

14, 114

stator

16, 116

rotor

18, 118

rotor shaft

19, 119

Three-speed transmission

20, 120

Rotor driven gear

22, 122

First countershaft

24, 124

Second countershaft

26, 126

planetary gear

28, 128

First difference wave

30, 130

Second difference wave

32, 132

total wave

34, 134

Planetary gear set input

36, 136

braking element

38, 138

casing

40, 140

Verblockungsschaltelement

42, 142

sun

44, 144

planet carrier

46, 146

ring gear

48, 148

First output gear

50, 150

Second output gear

51

Second output shaft

52, 152

differential gear

54, 154

Differential input gear

56

differential cage

58

sideshaft

60, 160

gear wheel

62, 162

Frictional switching element

63, 163

subtransmissions

64, 164

Axial direction

66, 166

First wheel plane

68, 168

Second wheel plane

Claims (11)

An electric drive train (10, 110) for a motor vehicle - comprising an electric machine (12, 112) having a stator (14, 114) and a rotor (16, 116), wherein the rotor (16, 116) rotatably with a Rotor shaft (18, 118) and a Rotorabtriebszahnrad (20, 120) is connected, - with a differential gear (52, 152) having a differential input gear (54, 154), - with a planetary gear (26, 126) which a planetary gear set comprising a first differential shaft (28, 128), a second differential shaft (30, 130), a sum shaft (32, 132), a braking element (36, 136) and a blocking switching element (40, 140), wherein the braking element (36, 136) is configured to non-rotatably connect the second differential shaft (30, 130) to a housing (38, 138), - a first countershaft (22, 122) coaxial with the single planetary gear set and parallel to the rotor shaft (18, 118) is arranged, and which rotatably with the sum shaft (32, 132) v a first output gear (48, 148) rotatably connected to the first countershaft (22, 122) and which is permanently engaged with the differential input gear (54, 154), the rotor output gear (20, 120) is permanently engaged with a planetary gear input gear (34, 134) rotatably connected to the first differential shaft (28, 128), characterized a second countershaft (24, 124) disposed parallel to the rotor shaft (18, 118) and parallel to the first countershaft (22, 122), and - a second output gear (50, 150) rotationally fixed to the second countershaft (24, 124), wherein a gear wheel (60, 160) coaxial with the second countershaft (24, 124) is permanently engaged with the rotor driven gear (20, 120), the second driven gear (50, 150) being permanent with the differential input gear (54, 154) is engaged. Electric drive train (10, 110) after Claim 1 , characterized in that the first countershaft (22) and the second countershaft (24) are each formed as a solid shaft. Electric drive train (10, 110) after Claim 1 , characterized in that the first countershaft (122) and the second countershaft (124) are each formed as a hollow shaft. Electric drive train (10, 110) according to one of the preceding claims, characterized in that the blocking switching element (40, 140) seen along the first countershaft (22, 122) on a side facing away from the electric machine (12, 112) side of the planetary gear (26 , 126) is arranged. Electric drive train (10, 110) according to one of the preceding claims, characterized in that the brake element (36, 136) seen along the first countershaft (22, 122) on a side remote from the electric machine (12, 112) side of the Planetenensatzeingangszradrads (34 , 134) is arranged. Electric drive train (10, 110) according to one of the preceding claims, characterized by a frictionally engaged shifting element (62, 162) which is arranged coaxially with the second countershaft (24, 124) and which is designed to rotate the gear wheel (60, 160). rotatably connected to the second output gear (50, 150) to connect. Electric drive train (10, 110) after Claim 6 , characterized in that the friction-locking switching element (62, 162) seen along the second countershaft (24, 124) on a side facing away from the electric machine (12,112) side of the second output gear (50, 150) and on one of the electric machine (12, 112) facing away from the gear wheel (60, 160) is arranged. Electric drive train (10, 110) according to any one of the preceding claims, characterized in that the braking element (36, 136) is designed positively. Electric drive train (10, 110) according to any one of the preceding claims, characterized in that the Verblockungsschaltelement (40, 140) is adapted to rotatably connect the first differential shaft (28, 128) with the second differential shaft (30, 130). Electric drive train (10, 110) after Claim 2 , characterized in that the Planetenensatzeingangszahnrad (34) rotatably connected to a ring gear (46) of the planetary gear (26) and that the second differential shaft (30) rotatably connected to a sun gear (42) of the planetary gear (26). Electric drive train (10, 110) after Claim 3 , characterized in that the planetary gear input gear (134) rotatably connected to a sun gear (142) of the planetary gear (126) and that the second differential shaft (130) rotationally fixed to a ring gear (146) of the planetary gear (126) is connected.

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