DE102013224499B4 - Optimized gear arrangement - Google Patents

Abstract

Gear arrangement for a vehicle with at least one housing (1a) which forms a first gear chamber (2) in which at least one planetary gear set (3a) and a spur gear (4) are accommodated, wherein a rotor (7) of an electric machine (8) is formed on a rotor shaft (5a) in an engine compartment (6), which rotor rotates around a stator (9) of the electric machine (8), wherein the spur gear (4) is indirectly connected to a gear shaft (12) arranged between the first gear chamber (2) and a second gear chamber (11), wherein the rotor shaft (5a) further has an axial bore (13) which carries lubricant and which is fluidically connected to a plurality of radial bores (14) arranged transversely thereto for lubricating the gear parts arranged on the rotor shaft (5a), wherein a fixed gear (10) which is operatively connected to the spur gear (4) is arranged on the gear shaft (12), wherein the fixed gear (10) is arranged in a lubricant sump (S) and circulates and distributes the lubricant by rotation, wherein a housing wall (15) is arranged in the first gear chamber (2) for collecting the lubricant and axially introducing the lubricant into the axial bore (13) of the rotor shaft (5a) radially to the fixed gear (10), characterized in that the planetary gear set (3a) and the spur gear (4) are arranged on the common rotor shaft (5a).

Description

The invention relates to a transmission arrangement for a vehicle with at least one housing that forms a first transmission chamber in which at least one planetary gear set and a spur gear are accommodated, which are arranged on a common rotor shaft on which a rotor of an electric machine is formed in an engine compartment, which rotates around a stator of the electric machine, wherein the spur gear is indirectly connected to a transmission shaft arranged between the first transmission chamber and a second transmission chamber, wherein the rotor shaft further has an axial bore that carries lubricant and is fluidically connected to a plurality of radial bores arranged transversely thereto for lubricating the transmission parts arranged on the rotor shaft.

Field of the invention

The field of application of the invention extends to transmission arrangements for electric and hybrid vehicles, in particular transmission arrangements comprising at least one electric machine and an unsynchronized transmission.

From the US 2009/ 0 233 749 A1 a composite planetary gear results which forms a gear chamber in which two planetary gear sets are housed, each comprising a sun gear, a pinion and a ring gear. The two planetary gear sets are arranged on a shaft consisting of two partial shafts. One shaft is driven by an electric motor and the other shaft by an internal combustion engine. The planetary gear sets act on a shaft which is connected to an axle differential and transmits the drive force to drive wheels. The shaft has an axial bore which carries lubricant and which is fluidically connected to radial bores arranged transversely thereto for lubricating the gear parts arranged on the rotor shaft. Furthermore, an oil pump is arranged at a distal end of the shaft to ensure lubrication. The oil pump pumps oil through the shaft, with the oil leaving the shaft again through the radial bores provided for this purpose at the points to be lubricated.

The EN 10 2011 076 527 A1 shows an electric drive for a vehicle with an electric machine which is coupled to an output via an intermediate gear, wherein a drive housing is provided which accommodates the electric machine and the intermediate gear and in which a common, passively operated oil circuit is provided for lubrication and/or cooling.

The EN 10 2011 076 523 A1 shows an axle drive for a vehicle with an electric machine as drive, which is coupled via an intermediate gear to an axle differential as output, wherein the intermediate gear comprises a planetary gear set and a spur gear stage, wherein the planetary gear set is connected via a sun gear to the electric machine and via a planetary gear carrier to the spur gear stage and wherein the ring gear is arranged fixed to the housing.

The EN 10 2011 080 036 A1 shows a wheel-mounted drive unit for a motor vehicle, in particular an electric vehicle, comprising an electric machine with a drive shaft and a transmission unit with at least a first transmission component with an output shaft, wherein the transmission unit interacts with the drive shaft to transmit torques, wherein the drive shaft is mounted by means of two drive shaft bearings and the output shaft is mounted by means of at least one output shaft bearing, wherein at least one of the drive shaft bearings and output shaft bearings is designed as a fixed bearing and at least one further one of the drive shaft bearings and output shaft bearings is designed as a floating bearing and wherein the drive shaft bearings and the output shaft bearings are designed as radial bearings, as well as a vehicle which comprises one or more electric motors alone as a drive.

It is common for planetary gears to have a separate oil pump to supply a central shaft with a sufficient oil volume flow to adequately lubricate, for example, bearings and planetary gear sets.

It is therefore the object of the present invention to further optimize a transmission arrangement with at least one planetary gear set so that the use of an oil pump is eliminated and the transmission arrangement is not only more compact but also has a reduced weight.

The object is achieved on the basis of a gear arrangement according to the preamble of claim 1 in conjunction with its characterizing features. The following dependent claims reflect advantageous developments of the invention.

According to the invention, a fixed gear operatively connected to the spur gear is arranged on the gear shaft, the fixed gear being arranged in a lubricant sump and circulating and distributing the lubricant by rotation, and a housing wall in the first gear chamber being arranged radially to the fixed gear for collecting the lubricant and axially introducing the lubricant into the axial bore of the rotor shaft. The lubricant supply is therefore speed-dependent. This is achieved by distributing lubricant through the fixed gear from the lubricant sump and collecting and introducing the lubricant into the axial bore of the rotor shaft through the housing wall. Depending on the speed, the lubricant is supplied from the axial bore of the rotor shaft to the gear parts to be lubricated. These include axial and radial bearings and planetary gear sets. The large number of radial bores arranged transversely to this preferably have different bore diameters for flow control. The larger the bore diameter of a radial bore, the greater the flow rate of the lubricant. The lubricant is particularly preferably a synthetic oil.

Preferably, a lubricant collecting tray is arranged on the front side at a first distal end of the rotor shaft for collecting the lubricant and introducing it into the axial bore of the rotor shaft, which partially protrudes into the axial bore of the rotor shaft and, together with the axial bore of the rotor shaft, forms an annular gap for guiding the lubricant. In other words, the lubricant collecting tray serves to guide the lubricant collected by the housing wall into the axial bore of the rotor shaft like a funnel. The annular gap also offers the possibility of guiding the lubricant specifically to a designated location.

The rotor shaft is particularly preferably supported by an angular contact ball bearing arranged at the first distal end, with the lubricant collecting tray coming into contact with an outer ring of the angular contact ball bearing at the front. The lubricant collecting tray is therefore not exposed to the rotation of the rotor shaft. The lubricant is directed into the angular contact ball bearing via the annular gap between the rotor shaft and the lubricant collecting tray.

Furthermore, a thrust washer is preferably arranged axially between the at least one planetary gear set and an axial bearing that comes into contact with a housing wall to collect the lubricant flowing through the radial bores and to introduce it into the at least one planetary gear set. The lubricant flowing through the radial bore of the rotor shaft is preferably introduced by the thrust washer into an axial bore formed in at least one bolt of the at least one planetary gear set and is led out again via at least one radial bore on the at least one bolt to lubricate the at least one planetary gear set. The lubricant returns to the lubricant sump via a return line.

The invention includes the technical teaching that at least one sealing element is arranged on the transmission shaft for fluidically separating the first transmission chamber from the second transmission chamber. As a result, the first transmission chamber can be operated with a different lubricant than the second transmission chamber.

According to a preferred embodiment, a bore for lubricant to escape is formed axially in the at least one housing between two sealing elements arranged on the gear shaft. The bore allows leaks to be detected so that if a sealing element is damaged, lubricant enters the lubricant-free space between the two sealing elements. The lubricant can escape through the bore formed in the housing, thereby indicating the leak.

Preferably, a sealing element is arranged axially between the first gear compartment and the motor compartment, and radially between the rotor shaft and the housing wall to fluidically separate the motor compartment from the first gear compartment. The sealing element thus prevents lubricant escaping through the radial bore of the rotor shaft from reaching the motor compartment and thus the electric machine.

According to a further preferred embodiment, the axial bore in the rotor shaft has at least one conical section for controlled lubricant guidance. The conical section is preferably designed such that an inner diameter of the rotor shaft increases towards the second distal end of the rotor shaft. Particularly preferably, a further, axially symmetrically arranged conical section borders the conical section, so that the enlarged inner diameter of the rotor shaft decreases again towards the distal end of the rotor shaft. The at least one conical section prevents the lubricant from running back along the taper. The lubricant is therefore guided in a controlled manner and depending on the speed from the small inner diameter of the axial bore to a large inner diameter of the axial bore.

Preferably, the axial bore in the rotor shaft can be closed by a plug arranged at a second distal end for sealing off lubricant. The plug is particularly preferably made of a metallic material and fluidically separates the first gear chamber from the motor chamber.

It is further proposed that the rotor shaft be designed in one or two parts. The one-part design of the rotor shaft has advantages in terms of manufacturing, whereas the two-part design of the rotor shaft has advantages in terms of assembly.

• 1 eine schematische Schnittansicht einer erfindungsgemäßen Getriebeanordnung, umfassend eine an einem unsynchronisierten Getriebe angeflanschte Elektromaschine, wobei eine Rotorwelle zweiteilig ausgebildet ist, und
• 2 eine Detailansicht einer erfindungsgemäßen Getriebeanordnung, fokussiert auf eine axial zwischen einem ersten Planetenradsatz und einer Gehäusewand angeordnete Anlaufscheibe, wobei die Rotorwelle einteilig ausgebildet ist.

Preferred embodiments of the invention are explained in more detail below with reference to the accompanying figures. These show:

• 1 a schematic sectional view of a transmission arrangement according to the invention, comprising an electric machine flanged to an unsynchronized transmission, wherein a rotor shaft is formed in two parts, and
• 2 a detailed view of a gear arrangement according to the invention, focused on a thrust washer arranged axially between a first planetary gear set and a housing wall, wherein the rotor shaft is formed in one piece.

Detailed description of the drawings

According to 1 a housing 1a forms a first gear chamber 2 in which a first and a second planetary gear set 3a, 3b are arranged. The two planetary gear sets 3a, 3b are mounted on a common rotor shaft 5a, 5b which is designed in two parts, with one part of the rotor shaft 5a being arranged essentially in the first gear chamber and another part of the rotor shaft 5b being arranged essentially in an engine chamber 6. The engine chamber is formed by a housing 1b, with the housing 1b being flanged to the housing 1a. A rotor 7 of an electric machine 8 is formed on the part of the rotor shaft 5b arranged in the engine chamber 6, which rotor rotates around a stator 9 of the electric machine 8.

Furthermore, a spur gear 4 is arranged on the rotor shaft 5a arranged in the first gear chamber 2, which is operatively connected to a fixed gear 10 formed on a gear shaft 12 of a gear (not shown here). The fixed gear 10 is arranged in a lubricant sump S and distributes the lubricant from the lubricant sump S by rotation. A housing wall 15 arranged radially to the fixed gear 10 in the first gear chamber 2 is provided for collecting the lubricant and axially introducing the lubricant into an axial bore 13 of the rotor shaft 5a.

To support this, a lubricant collecting tray 16 is arranged on the front side of a first distal end 18 of the rotor shaft 5a to collect the lubricant and introduce it into the axial bore 13 of the rotor shaft 5a. The lubricant collecting tray 16 partially protrudes into the axial bore 13 of the rotor shaft 5a and, together with the axial bore 13 of the rotor shaft 5a, forms an annular gap 17 for guiding the lubricant to an angular contact ball bearing 19 on which the rotor shaft 5 is mounted. The lubricant collecting tray 16 also comes to rest on the front side on an outer ring 20 of the angular contact ball bearing 19.

The lubricant is thus distributed via the fixed gear 10 from the lubricant sump S in the housing 1a. The lubricant is collected again by the housing wall 15 and introduced into the axial bore 13 of the rotor shaft 5 via the lubricant collecting tray 16. From the axial bore 13 of the rotor shaft 5, the lubricant reaches the gear parts to be lubricated via a large number of radial bores 14 arranged transversely to the axial bore 13, depending on the speed. The large number of radial bores 14 arranged transversely to this have different bore diameters for flow control. The lubricant thus flows from the first distal end 18 of the rotor shaft 5a through the axial bore 13 of the rotor shaft 5a in the direction of a second distal end 27 of the rotor shaft 5a.

The axial bore 13 of the rotor shaft 5a has two conical sections 26a, 26b for controlled lubricant guidance. These are formed in the rotor shaft 5a in such a way that an inner diameter of the axial bore 13 initially increases towards the second distal end 27 of the rotor shaft 5a, remains constant over a section and then decreases again. The axial bore 13 in the rotor shaft 5a can be closed by a plug 28 arranged at the second distal end 27 for sealing the engine compartment 6 with lubricant. Between the two conical sections 26a, 26b, a radial bore is formed in the rotor shaft 5a, which guides the lubricant into holes 30 provided for this purpose in bolts 31 of the planetary gear set 3a. The lubricant enters the planetary gear set 3a via the bores 30 and from there returns to the lubricant sump S via a return bore 29.

Furthermore, in a housing 1c, which is flanged to the front of the housing 1a, a bore 25 for the escape of lubricant is formed axially between two sealing elements 24a, 24b arranged on the gear shaft 12. The bore 25 can indicate a failure of one of the two sealing elements 24a, 24b.

According to 2 A thrust washer 23 is arranged axially between the planetary gear set 3a and an axial bearing 22 coming into contact with a housing wall 21 to collect the lubricant flowing through the radial bore 14 and to introduce it into the at least one planetary gear set 3a. Furthermore, a sealing element 24c is arranged axially between the first gear chamber 2 and the motor chamber 6, radially between the rotor shaft 5a and the housing wall 21 for fluid separation of the engine compartment 6 from the first transmission compartment 2.

List of reference symbols

1a, 1b, 1c

Housing

2

first gear room

3a, 3b

Planetary gear set

4

Spur gear

5a, 5b

Rotor shaft

6

Engine compartment

7

rotor

8

Electric machine

9

stator

10

Fixed gear

11

second gearbox compartment

12

Gear shaft

13

Axial bore

14

Radial holes

15

Housing wall

16

Lubricant tray

17

Annular gap

18

first distal end

19

Angular contact ball bearings

20

Outer ring

21

Housing wall

22

Axial bearing

23

Thrust washer

24a, 24b, 24c

Sealing element

25

Drilling

26

conical section

27

second distal end

28

Plug

29

Return bore

30

Drilling

31

Bolt

S

Lubricant sump

Claims (10)

Gear arrangement for a vehicle with at least one housing (1a) which forms a first gear chamber (2) in which at least one planetary gear set (3a) and a spur gear (4) are accommodated, wherein a rotor (7) of an electric machine (8) is formed on a rotor shaft (5a) in an engine compartment (6), which rotor rotates around a stator (9) of the electric machine (8), wherein the spur gear (4) is indirectly connected to a gear shaft (12) arranged between the first gear chamber (2) and a second gear chamber (11), wherein the rotor shaft (5a) further has an axial bore (13) which carries lubricant and which is fluidically connected to a plurality of radial bores (14) arranged transversely thereto for lubricating the gear parts arranged on the rotor shaft (5a), wherein a fixed gear (10) which is operatively connected to the spur gear (4) is arranged on the gear shaft (12), wherein the fixed gear (10) is arranged in a lubricant sump (S) and circulates and distributes the lubricant by rotation, wherein a housing wall (15) is arranged in the first gear chamber (2) for collecting the lubricant and axially introducing the lubricant into the axial bore (13) of the rotor shaft (5a) radially to the fixed gear (10), characterized in that the planetary gear set (3a) and the spur gear (4) are arranged on the common rotor shaft (5a). Gear arrangement according to Claim 1 , characterized in that a lubricant collecting tray (16) for collecting the lubricant and introducing it into the axial bore (13) of the rotor shaft (5a) is arranged on the front side at a first distal end (18) of the rotor shaft (5a), which tray partially projects into the axial bore (13) of the rotor shaft (5a) and together with the axial bore (13) of the rotor shaft (5a) forms an annular gap (17) for guiding the lubricant. Gear arrangement according to Claim 2 , characterized in that the rotor shaft (5a) is mounted via an angular contact ball bearing (19) arranged at the first distal end (18) and the lubricant collecting tray (16) comes to rest on the front side against an outer ring (20) of the angular contact ball bearing (19). Gear arrangement according to Claim 1 , characterized in that a thrust washer (23) for collecting the lubricant flowing through the radial bores (14) and introducing it into the at least one planetary gear set (3a) is arranged axially between the at least one planetary gear set (3a) and an axial bearing (22) coming into contact with a housing wall (21). Gear arrangement according to Claim 1 , characterized in that at least one sealing element (24a) for the fluidic separation of the first gear chamber (2) from the second gear chamber (11) is arranged on the gear shaft (12). Gear arrangement according to Claim 5 , characterized in that a bore (25) for the escape of lubricant is formed in the at least one housing (1a) axially between two sealing elements (24a, 24b) arranged on the transmission shaft (12). Gear arrangement according to Claim 1 , characterized in that a sealing element (24c) for fluidically separating the motor compartment (6) from the first gear compartment (2) is arranged axially between the first gear compartment (2) and the motor compartment (6), radially between the rotor shaft (5a) and the housing wall (21). Gear arrangement according to Claim 1 , characterized in that the axial bore (13) in the rotor shaft (5a) has at least one conical section (26) for controlled lubricant guidance. Gear arrangement according to Claim 1 , characterized in that the axial bore (13) in the rotor shaft (5a) can be closed by a plug (28) arranged at a second distal end (27) for lubricant sealing. Gear arrangement according to Claim 1 , characterized in that the rotor shaft (5a) is formed in one part or in two parts.

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