EP2750910A1

EP2750910A1 - Bearing arrangement for a drive device

Info

Publication number: EP2750910A1
Application number: EP11752207.8A
Authority: EP
Inventors: Frank Steiner; Ramon Jurjanz; Tomas Smetana
Original assignee: Schaeffler Technologies AG and Co KG
Current assignee: Schaeffler Technologies AG and Co KG
Priority date: 2011-09-01
Filing date: 2011-09-01
Publication date: 2014-07-09
Also published as: WO2013029683A1

Abstract

The invention relates to a bearing arrangement for a drive device (1) comprising at least one electric machine (3) with a rotor (7). Said rotor (7) is mechanically connected to a power transmission unit (8). Said power transmission unit (8) is mechanically coupled to a differential (4) by means of a pinion shaft (5) introduced into a rotor shaft (7a) of the rotors (7) of at least one electric machine (3). Said rotor shaft (7a) is mounted by means of a first roller bearing (9) and a second roller bearing (14) and the pinion shaft (5a) is mounted by means of a third roller bearing (15) and a fourth roller bearing (16). A bearing cartridge (20) receives the second roller bearing (14), the third roller bearing (15) and the forth roller bearing (16), an external ring (27) of the second roller bearing (14) being supported on the bearing cartridge (20).

Description

BEARING ARRANGEMENT FOR A DRIVE DEVICE

The present invention relates to a bearing assembly for a drive device. In particular, the bearing arrangement comprises at least one electric machine with a rotor which is mechanically connected to a power transmission unit. The power transmission unit is mechanically coupled to a pinion shaft guided through a rotor shaft of the rotor of the at least one electric machine with a differential. The rotor shaft is mounted by means of a first roller bearing and a second roller bearing and the pinion shaft by means of a third rolling bearing and a fourth rolling bearing. Background of the invention

Drive devices of the type described above are disclosed in German Offenlegungsschriften DE 37 05 607 A1, DE 10 2004 024 086 A1, US Pat.

DE 10 2006 023 577 A1 and US Pat. No. 4,004,472 A. The bearing of the rotor shaft and the pinion shaft takes place here in each case by means of two rolling bearings, but only the bearing of the rotor shaft is mounted on both sides in a single bearing plate, ie. a first and a second rolling bearing is each received by a separate bearing plate. Thus, a two-sided attachment to a housing of the drive device is required solely for the storage of the rotor shaft, whereby a lot of construction space is claimed.

The invention has for its object to provide a bearing assembly for a drive device that is simple, inexpensive and compact and therefore requires little space and is easy to install. The object is achieved by a bearing arrangement for a drive device comprising the features of claim 1.

The bearing arrangement according to the invention for a drive device comprises at least one electric machine with a rotor. The electrical machine can be switched either as an electric motor or as a generator and, in addition to the rotor, also includes a stator. The stator is attached to a housing of the drive device.

The rotor is mechanically connected to a power transmission unit. The power transmission unit is mechanically coupled to a pinion shaft guided through a rotor shaft of the rotor of the at least one electric machine with a differential. The rotor shaft is mounted by means of a first roller bearing and a second roller bearing and the pinion shaft by means of a third rolling bearing and a fourth rolling bearing. Furthermore, the rotor shaft is designed as a hollow shaft in which the pinion shaft is in contactless contact with the rotor shaft.

In particular, the power transmission unit may be a clutch or a transmission, such as a planetary gear. It is also conceivable that the power transmission unit is a combination of clutch or transmission. As a result of this arrangement, the pinion shaft guided through the at least one electric machine is mounted concentrically with the rotor shaft, with the stator and with the rotor along a main axis.

In particular, the mechanical coupling of the pinion shaft is an angle drive, which is further formed by a pinion and a ring gear. The pinion is, for example, a bevel gear which is non-rotatably mounted on the pinion shaft. The wheel is firmly attached to a differential cage of the differential. The differential is formed from the differential cage, in which differential gears are mounted and from Achswellenrädern which are rotatably mounted in the differential cage and are in mesh with the differential gears. The axis len are then provided with flanges through which connections are made with driven shafts / wheels. The angle drive thus created by the meshing of the pinion in a toothing of the ring gear.

According to the invention, a bearing cartridge accommodates the second rolling bearing, the third rolling bearing and the fourth rolling bearing. Furthermore, according to the invention, an outer ring of the second rolling bearing is supported on the bearing cartridge. In particular, a plurality of rolling elements of the third and fourth roller bearings are supported on the bearing cartridge, so that their outer Wälzkörperlaufbahnen are formed directly on the bearing cartridge. Due to the fact that the outer Wälzkörper- webs are formed directly on the bearing cartridge, the bearing cartridge for the majority of the rolling elements of the third and fourth bearings is a common running as an outer ring bearing ring.

In a first embodiment of the bearing arrangement according to the invention, the bearing cartridge is fastened with at least one flange to a housing of the drive device. Preferably, the attachment is designed as a screw connection.

The rotor shaft is received on an inner ring of the second rolling bearing. The rotor is thus attached via the inner ring and a plurality of Wälzköpern se of the second rolling bearing on the bearing cartridge and on the flange on the housing se.

In a further embodiment of the invention, a bearing plate receives the first rolling bearing. In this case, an outer ring of the first rolling bearing is supported on the end shield. The first rolling bearing further comprises a plurality of rolling elements, which are arranged radially between the outer ring and an inner ring belonging to the first rolling bearing. In particular, the rotor shaft is mounted here, as in the second rolling bearing, on the inner ring. About the end plate, the first roller bearing is attached to the drive device, preferably screwed. An advantage of the invention is that the arrangement of the second, third and fourth bearings in the bearing cartridge a compact and inexpensive construction is created, which only needs an attachment to the housing of the drive device. Another advantage of the bearing arrangement according to the invention for a drive device is that the movable bearing designed as a second bearing forms an interface between the rotor and the bearing cartridge, which allows easy assembly of both modules, ie structural components for the storage of pinion and rotor shaft. In a further embodiment, in each case at least one O-ring and in each case at least one sealing ring are arranged in an outer ring of the first rolling bearing and in an outer ring of the second rolling bearing. As a result, on the one hand, the engine compartment of the electric machine is separated from any oil of the oil-lubricated power transmission unit and, on the other hand, the rotor shaft is statically sealed.

In a further embodiment, a shaft shoulder of the rotor shaft and a retaining ring are associated with the first rolling bearing. Thus, the first rolling bearing is a fixed bearing, which is characterized in that the inner ring is supported to the left and fixed to the right with a circlip embedded in a shaft groove. Preferably, in the embodiment of the first rolling bearing as a fixed bearing, the second rolling bearing is a movable bearing. Both the first and the second rolling bearing is in a preferred embodiment, a ball bearing. In contrast, in a preferred embodiment, the third and the fourth rolling bearing is a tapered roller bearing. Both tapered roller bearings are preferably axially biased in a "0" arrangement by a preload nut.

In the following, embodiments of the invention and their advantages with reference to the accompanying figures will be explained in more detail. The proportions in the Figures do not always correspond to the actual size ratios, as some shapes are simplified and other shapes are shown enlarged in relation to other elements for ease of illustration. Showing:

1 shows an effect chain for explaining the operation of the bearing assembly according to the invention for a drive device according to Fig. 2.

FIG. 2 shows a schematic partial view of the bearing arrangement according to the invention for a drive device; FIG. and

Fig. 3 is a detail view of the section D of FIG. 2. For identical or equivalent elements of the invention, identical reference numerals are used. Furthermore, for the sake of clarity, only reference symbols are shown in the individual figures, which are required for the description of the respective figure. The illustrated embodiments are only examples of how the bearing assembly according to the invention for a drive device can be configured and thus do not represent a final limitation of the invention.

1 shows an action chain for explaining the mode of operation of the bearing arrangement according to the invention for a drive device 1 according to FIG. 2. The drive device 1 has at least one electric machine 3 and one differential 4. The electric machine 3 is mechanically coupled to the differential 4 via a power transmission unit 8, not shown in detail, such as a gearbox, with a pinion shaft 5 guided through a rotor shaft 7a (see FIG. 2).

A detailed description regarding the mechanical coupling and individual further bearing components has already been described in detail, so that a further description is omitted here. 2 shows a schematic partial view of the bearing assembly according to the invention for a drive device 1. In the illustrated embodiment, the drive device 1 comprises an electric machine 3 with a rotor 7 and a stator 6, both of which are arranged around a main axis 2.

As already described with reference to FIG. 1, the bearing arrangement of the drive device 1 comprises a rotor shaft 7a and a pinion shaft 5. The rotor shaft 7 is supported by a first rolling bearing 9 and a second rolling bearing 14, wherein the first rolling bearing 9 is a fixed bearing and the second rolling bearing 14 a floating bearing is (fixed-lot storage in Fig. 3 described in more detail). The floating bearing of the second rolling bearing 14 has the advantage that when the rotor shaft 7a expands due to temperature changes, the sliding seat of the floating bearing can compensate for this thermal expansion.

The pinion shaft 5 is supported by a third roller bearing 15 and a fourth roller bearing 16, which according to this embodiment as a tapered roller bearing in a "0" arrangement together with an inner ring 28 of the third roller bearing 15 and an inner ring 29 of the fourth bearing 16 by a Preload nut 40 (see Fig. 3) are axially biased.

According to the invention, a bearing cartridge 20 accommodates the second rolling bearing 14, the third rolling bearing 15 and the fourth rolling bearing 16, wherein an outer ring 27 (see FIG. 3) of the second rolling bearing 14 is supported on the bearing cartridge 20. Preferably, a plurality of rolling elements 15a of the third rolling bearing 15 and a plurality of rolling elements 16a of the fourth rolling bearing 16 are supported directly on the bearing cartridge 20 so that their outer rolling element raceways 15b, 16b are formed directly on the bearing cartridge 20. Furthermore, the storage cartridge 20 is screwed here with a flange 21 to a housing 22 of the drive device 1. Further elements are not shown here because of the overview, so that reference is made to FIG. 3 at this point.

As already mentioned, the first rolling bearing 9 is a fixed bearing, which is supported to the left by a shaft shoulder 33 of the rotor shaft 7a and to the right with a recessed into a shaft groove 35 locking ring 34 is fixed. The second rolling bearing 14 is a floating bearing. Both rolling bearings 9, 14 each have an O-ring 31 and a sealing ring 32, so that the electric machine 3 (see FIG. 2) is arranged separately from the oil-lubricated power transmission unit 8 (see FIG. 1) and furthermore the rotor shaft 7a is statically sealed.

The rotor shaft 7a is received on an inner ring 26 of the second rolling bearing 14. The rotor 7 is thus fixed to the housing 22 via the inner ring 26 and a plurality of Wälzköpern 14a from the second roller bearing 14 on the bearing cartridge 20 and the flange 21, as already shown in Fig. 2. The first rolling bearing 9 is accommodated in a bearing plate 12, which is screwed to the drive device 1. In this case, an outer ring 25 of the first rolling bearing 9 is supported on the bearing plate 12, wherein a plurality of rolling elements 9a are arranged radially between the outer ring 25 and an inner ring 24. Again, the rotor shaft 7a is mounted on the inner ring 24. The arrangement of the three rolling bearings 14, 15, 16 in the bearing cartridge 20 and the first roller bearing 9 in the bearing plate 12, a compact design is created, the total, ie for the rotor and pinion shaft, only two fasteners on the housing 22 of the drive device. 1 needed. LIST OF REFERENCE NUMBERS

1 drive device 27 outer ring of the second rolling bearing

2 main axis 28 inner ring of the third rolling bearing

3 Electrical machine 29 Inner ring of the fourth rolling bearing

4 differential 31 O-ring

5 pinion shaft 32 sealing ring

6 stator 33 shaft shoulder

7 Rotor 34 Circlip

7a rotor shaft 35 shaft groove

8 Power transmission unit D Section

9 first rolling bearing

9a rolling elements of the first rolling bearing

12 end shield

14 second rolling bearing

14a rolling elements of the second rolling bearing

15 third rolling bearing

15a rolling elements of the third rolling bearing

16 fourth rolling bearing

16a rolling elements of the fourth rolling bearing

20 storage cartridge

21 flange

22 housing

24 inner ring of the first rolling bearing

25 Outer ring of the first rolling bearing

26 inner ring of the second rolling bearing

Claims

1. Bearing arrangement for a drive device (1) having at least one electric machine (3) with a rotor (7), which is mechanically connected to a power transmission unit (8) and wherein the power transmission unit (8) with a by a rotor shaft (7a) of the rotor (7) of the at least one electric machine (3) guided pinion shaft (5) is mechanically coupled to a differential (4), wherein the rotor shaft (7a) by means of a first rolling bearing (9) and a second Rolling (14) and the pinion shaft (5) by means of a third roller bearing (15) and a fourth rolling bearing (16) is mounted, characterized in that a bearing cartridge (20) the second rolling bearing (14), the third rolling bearing

(15) and the fourth rolling bearing (16) receives and that an outer ring (27) of the second rolling bearing (14) on the bearing cartridge (20) is supported.

2. Bearing arrangement for a drive device (1) according to claim 1, wherein the bearing cartridge (20) with at least one flange (21) on a housing (22) of the drive device (1) is attached.

3. Bearing arrangement for a drive device (1) according to claim 1, wherein a bearing plate (12) receives the first rolling bearing (9) and an outer ring (25) of the first rolling bearing (9) on the bearing plate (12) is supported.

4. Bearing arrangement for a drive device (1) according to one of the preceding claims, wherein in an outer ring (25) of the first rolling bearing

(9) and in each case at least one O-ring (31) and in each case at least one sealing ring (32) is arranged in an outer ring (27) of the second rolling bearing (14).

5. Bearing arrangement for a drive device (1) according to one of the preceding claims, wherein the first rolling bearing (9) has a shaft shoulder (33) of the rotor shaft (7a) and a securing ring (34) is associated.

6. Bearing arrangement for a drive device (1) according to one of the preceding claims, wherein the first rolling bearing (9) is a fixed bearing and the second rolling bearing (14) is a floating bearing.

7. Bearing arrangement for a drive device (1) according to one of the preceding claims, wherein the first roller bearing (9) and the second rolling bearing (14) is a ball bearing.

8. Bearing arrangement for a drive device (1) according to one of the preceding claims, wherein the third rolling bearing (15) and the fourth rolling bearing (16) is a tapered roller bearing.