WO2014056577A1

WO2014056577A1 - Planetary differential

Info

Publication number: WO2014056577A1
Application number: PCT/EP2013/002890
Authority: WO
Inventors: Peter Appeltauer
Original assignee: Daimler Ag
Priority date: 2012-10-11
Filing date: 2013-09-26
Publication date: 2014-04-17
Also published as: DE102012019901A1

Abstract

The invention relates to a planetary differential with an annular gear (11), a planetary gear support (12) and at least one annular gear bearing (13, 14) which bears the annular gear (11), the at least one annular gear bearing (13, 14) bearing the annular gear (11) on the planetary gear (12), and further relates to a motor vehicle drive train with at least one planetary differential (10) of this kind.

Description

planetary differential

The invention relates to a planetary differential according to the preamble of claim 1 and a motor vehicle drive train according to claim 10.

From DE 101 40 229 A1, a planetary differential with a ring gear, a planet carrier and a ring gear bearing supporting the ring gear is already known.

The invention is in particular the object of the weight of the

To reduce planetary differential, in particular to reduce the weight of a motor vehicle. This object is achieved by an inventive planetary differential according to claim 1 and a motor vehicle drive train according to claim 10. Further developments of the invention will become apparent from the dependent claims.

The invention is based on a planetary differential with a ring gear, a

Planetary gear and at least one ring gear bearing which supports the ring gear.

It is proposed that the at least one ring gear bearing supports the ring gear on the planet carrier. As a result, the planet carrier can be used to support the ring gear, whereby at least one component of the planetary differential, in particular a differential housing, can be dispensed with without replacement. By dispensing with the component, in particular the differential case, the

Be carried out open planet carrier, causing further action for

Reduction of a weight of the planetary differential can be made, such as the machining of outer races of a constant velocity joint of a side shaft in a component. Thereby, the weight of the planetary differential can be reduced, whereby when using the planetary differential in a motor vehicle drive train, a weight of the motor vehicle drive train and thus a Fuel consumption of a motor vehicle powertrain having motor vehicle can be reduced. Under a "planetary differential" is in particular a

Differential, which has at least one planetary gear connected to the planet gear, which is coupled in the radial outward direction with the ring gear and in the radial direction inwardly with a sun gear. The

Planet differential is preferably formed as an axle differential. The term "radial" is here referred in particular to an axis of rotation of the ring gear, so that the term "radially" denotes a direction which is perpendicular to the axis of rotation.

For a particularly advantageous mounting of the ring gear is further proposed that the at least one ring gear is designed as a rolling bearing, whereby the ring gear can be stored particularly wear.

To further reduce weight is also proposed that the

Planet differential has at least one carrier bearing, which is intended to support the planet carrier on a housing, whereby the planet carrier can be stored particularly weight-saving. Preferably, the carrier bearing is designed as a roller bearing, whereby the planet carrier can be stored particularly wear. By "provided" is to be understood in particular specially designed, equipped and / or arranged.

In order to store the ring gear particularly reliably, it is particularly advantageous if the planetary differential has at least one further ring gear bearing which supports the ring gear on the planet, and has at least a first intermeshing with the ring gear planet, which is arranged axially between the at least two Hohlradlagern , By this arrangement, the first planetary gear required space can be reduced, whereby the planetary differential can be made very compact. Advantageously, the planet carrier supports the at least one planetary gear. The first planetary gear is advantageously directly in engagement with the ring gear. The term "axial" is here in particular related to the axis of rotation of the ring gear, so that the term "axially" denotes a direction which extends on the axis of rotation or parallel to this.

To provide a high system integration, it is also advantageous if the planetary differential has at least one meshing with the first planetary gear second planetary gear, which is arranged axially between the at least two Hohlradlagern, and has a sun gear, which meshes with the second planetary gear. This can a load on an internal toothing of the ring gear can be reduced, whereby the internal toothing can be performed axially narrower compared to an external toothing of the ring gear. The second planetary gear is advantageously directly in engagement with the first planetary gear and with the sun gear.

For space-saving provision of at least one raceway of the at least one Hohlradlagers, it is also advantageous if the ring gear has an outer toothing and an inner toothing, wherein an axial extent of the outer toothing is greater than an axial extent of the internal toothing. As a result, a space-saving support of the ring gear on the planet carrier can be realized, whereby the compactness of the planetary differential further increases and the weight of the

Planetendifferentials can be further reduced. Preferably, the

External toothing of the ring gear for initiating a drive power in the

Planet differential provided. The ring gear advantageously forms a drive wheel. The internal toothing advantageously meshes with the first planetary gear.

For multi-part design of the planet carrier is further proposed that the planet carrier at least a first planet carrier member and a second

Has planet carrier part and at least the first planetary gear axially between the first planet carrier member and the second planet carrier member is arranged, whereby a mounting can be simplified. Preferably, the at least two

Planet carrier parts connected to each other by means of at least one Planetenradbolzens.

It is particularly advantageous if at least one of the at least two

Planet carrier parts at least partially forms a joint housing, which further weight can be saved. Preferably, at least one planet carrier part is formed integrally with the joint housing. Preferably, at least one of the at least two planet carrier parts at least partially forms a joint housing of a constant velocity joint of a side shaft of a motor vehicle drive train.

In a particularly advantageous embodiment, the ring gear bearing is a

Angular contact ball bearings formed, whereby the ring gear bearing can accommodate axial and radial loads.

Furthermore, a motor vehicle drive train having at least one planetary differential according to the invention is proposed. This can be a weight of

Motor vehicle powertrain can be reduced, thereby reducing fuel consumption and so that a pollutant emission of the motor vehicle drive train having motor vehicle can be reduced.

For the motor vehicle drive train is also proposed that the sun gear for driving a first motor vehicle wheel and the planet carrier for driving a second motor vehicle wheel is provided, whereby a particularly light final drive can be provided. Preferably, the drive power is discharged via the sun gear to one of the driven motor vehicle wheels and via the planet carrier to the further driven motor vehicle wheel from the planetary differential.

Further advantages will become apparent from the following description of the figures. In the figures, an embodiment of the invention is shown. The figures, the description of the figures and the claims contain numerous features in combination. The person skilled in the art will expediently also consider the features individually and combine them into meaningful further combinations.

Showing:

Fig. 1 shows schematically a planetary differential of a final drive for a

Motor vehicle and

Fig. 2 is a diagram of a toothing of the planetary differential.

Figures 1 and 2 show a part of a final drive of a

Motor vehicle drive train for a two-lane motor vehicle. The final drive has a planetary differential 10, which drives a drive power to both

Vehicle wheels of an axle of the motor vehicle distributed in equal proportions. The planetary differential 10 is designed as a spur gear. The planetary differential 10 is advantageously used in front-wheel drive motor vehicles whose engine and transmission are arranged transversely. In principle, the planetary differential 10 can also be used in rear-wheel drive vehicles with a longitudinal drive train.

Trained as an axle differential planetary differential 10 has a ring gear 11, a planetary gear 12 and two ring gear bearings 13, 14 which support the ring gear 11, on. The two ring gear bearings 13, 14 support the ring gear 11 respectively on the planet carrier 12. The ring gear 11 is supported by the ring gear bearings 13, 14 on the planet carrier 12 from. The ring gear bearings 13, 14 are each formed as a rolling bearing. In this

Embodiment, the ring gear bearings 13, 14 each as an angular contact ball bearing educated. The ring gear bearings 13, 14 have trained as balls rolling elements 24, 25. In this case, the ring gear 11 forms an outer raceway for the rolling elements 24, 25 and the planet 12 an inner raceway for the rolling elements 24, 25 from. The outer race of the ring gear 11 and the inner race of the planet carrier 12 are offset from each other in the direction of a bearing axis. One of the ring gear bearings 13 supports the ring gear 11 at a first end side and the other

Hollow wheel bearing 14 on a second end face. The ring gear 11 is a spur gear

executed.

An order of magnitude of the ring gear bearings 13, 14 corresponds to at least approximately one order of magnitude of a so-called thin-ring bearing. The rolling elements 24, 25 have a diameter of 6.35 mm. A pitch diameter is about 180 mm. A helix angle is 30 °. A rolling element cage is made of sheet steel.

In principle, however, the roller cage can also consist of a different material. Characterized in that the ring gear bearings 13, 14 of the support of the ring gear 11 rotate only at differential speed of the drive wheels of the axis, no functional limits are set with the comparatively low permissible speed of this type of bearing.

For storage of the planet carrier 12, the planetary differential 10 has two

Carrier bearing 15, 16, which the planet carrier 12 at a not shown

Housing of the final drive is stored. The ring gear bearings 13, 14 are arranged axially between the two carrier bearings 15, 16. The carrier bearings 15, 16 are formed as rolling bearings. In this case, the carrier bearing 15 is designed as a tapered roller bearing and the carrier bearing 16 as an angular contact ball bearing. In this embodiment, the support bearings 15, 16 each have an inner ring 26, 27 which is fixedly arranged on the planet carrier 12, and in each case an outer ring 28, 29 which is fixedly connected to the housing on.

In principle, the inner rings 26, 27 may be integrally formed with the planet carrier 12 and / or the outer rings 28, 29 integrally with the housing.

The planetary differential 10 further includes three Planetenradpaare 30 and a single sun gear 19. The Planetenradpaare 30 and the sun gear 19 are arranged axially between the two Hohlradlagern 13, 14. The three mutually parallel

Planetenradpaare 30 are distributed along a circumference around the sun gear 19. The Planetenradpaare 30 operatively connect the ring gear 1 1 and the sun gear 19 with each other. In this case, the planet carrier 12 receives the Planetenradpaare 30. In Figures 1 and 2, only one of the three Planetenradpaare 30 is shown. For better understanding in the figure 2, the Planetenradpaar 30 and Sun gear 19 shown rotated by 90 °, which is why the Planetenradpaar 30 and the sun gear 19 are shown in dashed lines. Basically, one to four pairs of planetary gears 30 can be accommodated in an existing installation space with different sizes of the design, which is an adaptation to the required torque class of

Planet differential 10 allowed.

The three Planetenradpaare 30 each have two meshing planetary gears 17, 18. The two planet gears 17, 18 are the same size. The first planet gear 17 meshes with the ring gear 11 and the second planet gear 18 with the sun gear 19. The planet gears 17, 18 are arranged axially between the two Hohlradlagern 13, 14. Here, the planet carrier 12 forms a first output and the central sun gear 19 has a second output. Thus, the planet carrier 12 is provided for driving one of the drivable motor vehicle wheels of the axle and the sun gear 19 for driving the other drivable motor vehicle wheel of the axle. In one

Operating state in which a drive power via the ring gear 11 in the

Planet differential 10 is initiated, the planet carrier 12 drives one of the drivable motor vehicle wheels of the axle and the sun gear 19 the other

driven motor vehicle wheel of the axis. About the choice of different

Gear sizes can be achieved a range of different ratios of distributed to the two drives drive power. If the diameter of the active circle of the ring gear 11 is exactly twice as large as a diameter of the

Active circle of the sun gear 19, the planetary differential 10 is symmetrical, whereby the planetary differential 10 distributes the initiated drive power in equal parts to the two drivable vehicle wheels of the axle.

To initiate the drive power in the planetary differential 10, the ring gear 11 is formed as a drive wheel. The ring gear 1 1 has an external toothing 20 and an internal toothing 21, wherein an axial extent of the external toothing 20 is greater than an axial extent of the internal toothing 21. Due to the load distribution on the three Planetenradpaare 30, the internal toothing 21 of the ring gear 1 1 in comparison to the outer teeth 20 of the ring gear 11 is less loaded, whereby the internal teeth 21 is made narrower than the outer teeth 20. The first planetary gear 17 of each of Planetenradpaare 30 is directly engaged with the

Internal toothing 21 of the ring gear 11. The internal toothing 21 is arranged axially between the two Hohlradlagern 13, 14. A portion of the ring gear 11, which by the smaller axial extent of the

Internal toothing 21 is available, thereby forming the raceways for the rolling elements 24, 25 and thus for supporting the ring gear 11 on the

Planet wheel 12 used. In this embodiment, the ring gear 11, the planetary gears 17, 18 and the sun gear 19 are straight-toothed. This design is particularly suitable for motor vehicles, which are equipped with electronic stability programs (ESP), as these not only on no locking effect in the planetary differential

10 are dependent, but additional friction in the planetary differential 10 interferes with the function of these stability programs. Just as in the storage of the ring gear 11, there is movement in the planetary gear even at differential speed of the drive motor vehicle wheels, so they can also be performed straight teeth.

For different requirements, the planetary gear can also be performed helical. The resulting axial forces can be used to represent a self-locking effect of the planetary differential 10. Further, additional, additional locking arrangements may be added to the planetary differential 10, such as hydraulic or electro-actuated transverse locks or relative speed independent torque distribution devices.

The planet carrier 12 is formed in two parts. The planet carrier 12 has a first planet carrier part 22 and a second planet carrier part 23, wherein the

Planet gears 17, 18 are arranged axially between the first planet carrier member 22 and the second planet carrier member 23. Here, the internal toothing 21 of the ring gear

11 axially disposed between the two planet carrier parts 22, 23. The sun gear 19 is also arranged axially between the two planet carrier parts 22, 23. The first planet carrier part 22 forms the raceway for the rolling elements 24 of the ring gear bearing 13 and the second planet carrier part 23, the track for the rolling elements 25 of the ring gear 14. The carrier bearing 15 supports the first planet carrier part 22 and the

Carrier bearing 16, the second planet carrier member 23 to the housing, not shown.

The planetary differential 10 further has six planet gear 31, which connect the two planet carrier parts 22, 23 with each other. For axial securing the Planetenradbolzen 31 each have at one axial end a stop and at another axial end a groove. In an assembled state, the stop of the Planetenradbolzen 31 abuts against the first planet carrier member 22. The groove of

Planetenradbolzen 31 forms a receptacle of a bayonet closure. In the figures 1 and 2 is only one of the six planetary wheel 31 visible. In order to ensure an axial distance and a required flat position of the two planet carrier parts 22, 23 and thus the raceways of the rolling elements 24, 25, the sun gear 19 and all planet gears 17, 18 ground together on a magnetic table axially as a set, whereby both conditions realized cost can be.

The first planet carrier part 22 further forms a joint housing of a constant velocity joint, not shown, of a side shaft of the final drive. The first planet carrier member 22 and the joint housing are integral and thus formed as a common component. The side shaft of the final drive, not shown, connects via the unidirectional joint, not shown, the planetary carrier 12 drivingly with one of the drivable motor vehicle wheels of the axis, wherein the joint housing of the

Constant velocity joint is formed integrally with the first planet carrier member 22. The final drive has a further, not shown, side shaft, which connects the sun gear 19 in terms of drive technology with the other drivable motor vehicle wheel of the axle via a further, not shown constant velocity joint. For this purpose, the final drive on a connecting shaft 32, which drives the sun gear 19 to the

Side shaft ties. The sun gear 19 is rotatably mounted on the connecting shaft 32. The one-piece design of the Planetenradträgers 12 with the

Joint housing is in vehicles with a front-transverse gear on one side, on a side facing away from an engine of the motor vehicle side, and in rear-wheel drive vehicles with longitudinal drive train even on both sides possible.

Claims

claims

1. planetary differential with a ring gear (11), a planet carrier (12) and at least one ring gear bearing (13, 14) which supports the ring gear (11), characterized in that

the at least one ring gear bearing (13, 14) the ring gear (1 1) on the

Planet carrier (12) stores.

2. planetary differential according to claim 1,

characterized in that

the at least one ring gear bearing (13, 14) is designed as a roller bearing.

3. planetary differential according to claim 1 or 2,

marked by

at least one carrier bearing (15, 16), which is provided to the

Store planet carrier (12) on a housing.

4. planetary differential according to one of the preceding claims,

marked by

at least one further ring gear bearing (13, 14), which supports the ring gear (11) on the planet carrier (12), and at least one first with the ring gear (1 1) meshing planetary gear (17) axially between the at least two Hohlradlagern (13 , 14) is arranged.

5. planetary differential according to claim 4,

marked by

at least one second planetary gear (18) meshing with the first planetary gear (17) disposed axially between the at least two ring gear bearings (13, 14) and a sun gear (19) meshing with the second planetary gear (18).

6. planetary differential according to one of the preceding claims,

characterized in that

the ring gear (11) has an outer toothing (20) and an inner toothing (21), wherein an axial extent of the outer toothing (20) is greater than an axial extent of the inner toothing (21).

7. planetary differential at least according to claim 4,

characterized in that

the planet carrier (12) has at least a first planet carrier part (22) and a second planet carrier part (23) and at least the first planet gear (17) axially between the first planet carrier part (22) and the second

Planet carrier part (23) is arranged.

8. planetary differential according to claim 7,

characterized in that

at least one of the at least two planet carrier parts (22, 23) at least partially forms a joint housing.

9. planetary differential according to one of the preceding claims,

characterized in that

the ring gear bearing (13, 14) is designed as an angular contact ball bearing.

10. Motor vehicle drive train with at least one planetary differential (10) according to one of the preceding claims.

11. Motor vehicle drive train according to claim 10,

characterized in that

the sun gear (19) is provided for driving a first motor vehicle wheel and the planet carrier (12) is for driving a second motor vehicle wheel.