CN114207321A

CN114207321A - Compact transmission device with multi-stage planetary gear set and spur gear differential

Info

Publication number: CN114207321A
Application number: CN202080055478.8A
Authority: CN
Inventors: 弗洛里安·赖因勒; 约亨·洛菲尔曼; 巴斯蒂安·鲁普; 塞巴斯蒂安·朗汉斯; 约尔格·鲍尔
Original assignee: Schaeffler Technologies AG and Co KG
Current assignee: Schaeffler Technologies AG and Co KG
Priority date: 2019-08-05
Filing date: 2020-07-15
Publication date: 2022-03-18
Anticipated expiration: 2040-07-15
Also published as: CN114207321B; DE102019121079B3; WO2021023338A1

Abstract

The invention relates to a transmission device (1) for a motor vehicle, comprising a multi-stage planetary gear set (2) and a spur gear differential (3) which are connected via a common planet carrier (4) and which have a first and a second planetary gear set (6, 7) which mesh with one another in pairs, wherein each planetary gear set (6, 7) comprises a sun gear (13, 14) which is rotationally fixedly connected to an output shaft (15, 16) of the spur gear differential (3), wherein a torque introduced into the transmission device (1) via an input shaft is transmitted from the multi-stage planetary gear set (2) into the spur gear differential (3) and subsequently onto the output shafts (15, 16) and thus onto the driven wheel, wherein the meshing plane of the multi-stage planetary gear set (2) and at least one sun gear (13) of the spur gear differential (3), 14) radial overlap, wherein the compensating wheel pins (10, 11) of the multi-stage planetary gear set (2) are guided at a radial distance from the sun gears (13, 14) through the meshing plane of the spur gear differential (3) and fix the differential cover (12) radially and axially on the end side, and the planet carrier (4) is mounted in the housing (4) via a floating bearing (34) which is obtained by the toothing of the input sun gear (39) of the multi-stage planetary gear set (2) and of the spur gear (17) forming a double planetary gear and via a fixed bearing (36) on the opposite side by means of the differential cover (12).

Description

Compact transmission device with multi-stage planetary gear set and spur gear differential

Technical Field

A transmission device for a motor vehicle according to the features of the preamble of claim 1, comprising a multi-stage planetary gear set and a spur gear differential connected via a common planet carrier.

Background

DE 102015214031 a1 shows a transmission device for a motor vehicle, which comprises a transmission input stage and a differential connected thereto via a common planet carrier. A differential constructed as a spur gear differential has two planetary gear sets, the planet gears of which mesh with separate sun gears. Furthermore, the two planetary gear sets of the differential mesh with each other in pairs. The transmission input stage has a drive sun gear, which meshes with a first planetary gear set, which is connected to a second planetary gear set in a rotationally fixed manner.

A transmission device associated with an electric drive unit is known from EP 2821672 a1, comprising a rotor shaft as an input shaft, as well as a differential and a multi-stage planetary gear set, also referred to as a transmission input stage, which is designed as a planetary gear transmission, the sun gear of which is associated with the input shaft. A differential constructed as a spur gear differential includes planet gears as the compensating wheels and sun gears as the driven wheels, with each sun gear being associated with an output shaft. The torque introduced via the input shaft is introduced via the multi-stage planetary gear set into the spur gear differential and is transmitted from there to the output shaft and subsequently to the driven vehicle wheels. The input shaft forms a hollow shaft through which one of the output shafts is guided.

Disclosure of Invention

The invention is based on the object of providing a transmission device for a drive device that is compact at least in the axial direction, which transmission device can be installed in a simple manner and can be implemented cost-effectively.

This object is achieved by a transmission device having the features of claim 1. Preferred and/or advantageous embodiments of the invention emerge from the dependent claims, the following description and the enclosed drawings.

According to the invention, the planet wheel pins of the multi-stage planetary gear set are arranged with a radial distance from the sun wheel of the spur wheel differential through the meshing plane of the spur wheel differential, and the compensating wheel pins also fix the differential cover radially and axially at the end facing away from the multi-stage planetary gear. In order to support the planet carrier, it is proposed that the planet carrier be supported in a housing of the transmission device on the drive side of the transmission device via running toothing of the large planet gears as a floating bearing and on the opposite side by means of a differential cover via a fixed bearing.

Due to the inventive concept of axial expansion including a spur gear differential, an axially compact spur gear differential can be advantageously achieved, which at the same time positively influences the required installation space of the entire transmission device. Due to the spur gear differential, which extends in the radial direction, a radial overlap occurs at least between the meshing planes of the multi-stage planetary gear set and the spur gear differential. In order to achieve this solution, the planet pin of the multi-stage planetary gear set is axially extended, so that the planet pin can guide and fix the differential cover. Advantageously, the compact concept according to the invention results in a desired smaller deformation of the planet carrier, which positively influences the torsional rigidity of the transmission device.

Furthermore, the compact design according to the invention enables alternative, cost-effective production methods for the individual components of the transmission device, such as cold-forming methods, for example deep-drawing, punching or pressing, which ensure improved rigidity overall even with reduced wall thicknesses.

The bearing arrangement of the planet carrier, which is designed according to the invention, comprises a floating bearing on the drive side, which is obtained by the meshing engagement of the large double planet gears with the input sun gear. On the output side, a differential cover, which is connected to the planet carrier in a rotationally fixed manner, is preferably mounted in a transmission housing of the transmission device via a fixed bearing in the form of a deep-groove ball bearing.

In an advantageous embodiment, which is directed to an axially compact design of the transmission device, the sun gear of the spur gear differential is arranged close to the planet gear carrier according to the invention. In order to achieve the smallest possible axial distance, recesses are introduced in the guide support of the planet carrier, in each case locally close to the compensating wheel pins, which recesses enable an unimpeded rotation of the sun wheel.

In a preferred embodiment of the spur gear differential, the outer envelope circle of the spur gear differential is smaller than the tip circle of the internal toothing of the associated ring gear. By means of said measures, a simplified mounting sequence occurs, since the engagement of the ring gear is cancelled before the spur gear differential is mounted via the planet gears.

According to the invention, the compensating wheel bolts of the spur gear differential are axially fixed in the mounted state in a form-fitting manner via the component geometries of the differential cover and of the planet carrier. In this case, the compensating wheel bolt is preferably inserted with one end side into a blind hole of the planet carrier and with the other end side into a hole of the differential cover and is supported at a radially inward edge of the differential cover. For cost reasons, additional positive and/or positive rotational locking can be dispensed with.

The permanent fixing of the position of the planet pins of the multi-stage planetary gear set is carried out by means of a press-fit connection at the two flexible ends of the planet pins. The crimped connections of the planet pin produce a play-free fastening at the differential cover and the planet carrier, which does not require a supplementary press fit of the pin in the planet carrier.

The crimp brings about a connection which is durable and which is also subject to high mechanical demands, such as vibrations which occur, for example, in the operating state of the transmission device.

Preferably, for crimping the planet pin, a crimping tool is used which has a special profile which firstly has an acute angle which is then configured more and more gently, whereby the deformation increases at the same time as the axial crimping path increases. By means of this measure, the loadability of the crimping section can be improved while the crimping force remains unchanged. The clamping of the planet gear pins, which is also referred to as the clamping flag, furthermore results in an improved torsional stiffness of the planet gear carrier, which, for example, positively influences the mounting of the planet gears, reduces the meshing forces of the gears and thus optimizes the service life of the entire transmission device.

The multi-stage planetary gear set is free, wherein the planetary gears, also referred to as spur gears, are supported via rolling bearings configured as needle rings. All the planet gears are centered via the planet gear pegs and the needle ring. The required release of the planetary gear set for load compensation takes place via the associated ring gear. For spur gears, also referred to as gearing, of the multi-stage planetary gear set, which are each associated with a planetary gear pin, an axial spacing of at least 6mm is provided for cost-effective production.

The transmission device comprises a lubricating device, wherein the associated compensating wheel pin has a blind hole or a longitudinal bore closed on one side in a mounting-related manner in order to lubricate the rotatably mounted compensating wheels or spur gears of the spur gear differential and of the multi-stage planetary gear set in a targeted manner. Preferably, an oil pan is inserted into the end face of the compensating wheel pin of the spur gear differential. Via an oil sump, which is also referred to as a guide plate and preferably connects all the planet pins all around, in the operating state oil or oil mist is contained in the transmission device due to centrifugal forces, is subsequently guided into the longitudinal bore and from there is supplied to the bearing device via the radial bores of the planet pins.

The planet pin associated with the multi-stage planetary gear set preferably forms a partition wall centrally in the longitudinal bore to form a blind bore, so that the incoming lubricating oil can then flow via the radial bores to the axially offset bearings of the spur gears.

Preferably, in order to manufacture the teeth of the multi-stage planetary gear set and/or the spur gear differential, strong scraping teeth are suitable. The power scraping tooth is a method for continuous cutting for manufacturing a tooth portion. The production process combines roll milling and impact caused by continuous rolling by axial feed and enables the production of inner and outer teeth. The proposed high-force scraper tooth enables a high cross-axis angle to be achieved at a large distance, so that tool wear and thus costs can be reduced. In order to achieve a cost-effective production overall, the teeth of the multi-stage planetary gear set are preferably arranged axially at a distance of at least 6mm from one another.

The transmission device according to the invention, which is of compact design and comprises a spur gear differential and a multi-stage planetary gear set, is preferably suitable for a drive train of an electric drive unit of a motor vehicle. For example, it is suitable to couple the transmission device to an electric motor to form a so-called E-axle. The E-axle is a solution for electric or hybrid applications for purely electric vehicles. In the case of an E-axle, the components, such as the motor, the axle and the transmission, are combined to form a structural unit, which are used separately in a conventional manner.

Drawings

The invention is described in detail below on the basis of embodiments shown in the three drawings. The invention is not, however, limited to the embodiments shown. The figures show:

FIG. 1 shows a longitudinal cross section of a transmission arrangement constructed in accordance with the present invention including a spur gear differential and a multi-stage planetary gear set;

FIG. 2 illustrates a partial three-dimensional view of a spur gear differential and a multi-stage planetary gear set of the transmission arrangement according to FIG. 1;

FIG. 3 shows a front view of the planetary gear sets of the spur gear differential and the gears of the multi-stage planetary gear set;

FIG. 4 shows a detail view of a spur gear differential through a transmission arrangement.

Detailed Description

The following description of the drawings of embodiments applies to a better understanding of the invention. Identical components are provided with the same reference numerals here.

The construction and arrangement of the individual components of the transmission device 1 according to the invention according to a preferred embodiment is depicted in fig. 1, wherein not all components of the transmission device 1 are shown in fig. 1. The transmission device 1, which is associated for example with a drive train (not shown) of an electric drive of a motor vehicle, is divided into a multi-stage planetary gear set 2 and a spur gear differential 3. In a multi-stage planetary gear set 2, which is also referred to as a transmission section or a reduction stage, the drive torque introduced by, for example, an E-motor (not shown) is converted or reduced from a high input speed to a low output speed. The output torque achieved is then distributed via the spur gear differential 3 to its output shafts connected to the drive wheels of the motor vehicle. For the multi-stage planetary gear set 2 and the spur gear differential 3, a planetary gear carrier 4 is provided, which is inserted into a housing 5 of the transmission device 1.

The planet carrier 4 is rotatably mounted on the drive side via a meshing engagement, which is formed for example as a floating bearing 34, between the input sun gear 39, which surrounds the output shaft 15, and the large planet gears 17. The carrier 4 is supported on the driven side via a fixed bearing 36. For this purpose, deep-groove ball bearings are provided, which are inserted between a receptacle 37 of the transmission housing 5 of the transmission device 1 and a cylindrical, axially projecting shoulder 38 of the differential cover 12, which is connected in a rotationally rigid manner to the planet carrier 4.

The spur gear differential 3, as shown in fig. 2, comprises two planetary gear sets 6, 7 with differently dimensioned compensating wheels, namely a wide compensating wheel 8 and a narrow compensating wheel 9, which are each rotatably mounted on associated compensating wheel pins 10, 11, which are inserted in a rotationally fixed manner into associated bores of the planet carrier 4 and of the differential cover 12. Radially on the inside, the compensating

wheels

8, 9 are in engagement with a

sun wheel

13, 14, respectively, wherein each

sun wheel

13, 14 is connected in a rotationally fixed manner to an

output shaft

15, 16.

The multi-stage planetary gearset 2 comprises a gearing, two

spur gears

17, 18 each axially offset, having an oblique gearing and connected to one another, also referred to as planet gears, which are in engagement with further gears (not shown) being rotatably mounted on a planet gear bolt 21 via rolling

bearings

19, 20.

Rolling bearings

19, 20 are preferably needle rings (KZK). In order to achieve cost-effective production, two

spur gears

17, 18 of different dimensions, which are offset from one another, are arranged at an axial distance of 6mm or more. Furthermore, the multi-stage planetary gear set 2 or its planetary gear pegs 21 in the installed state overlaps the sun gears 13, 14 and thus the meshing plane of the spur gear differential 3. With a view to the axially compact design of the transmission device 1, the engagement plane of the sun gear 13 of the spur gear differential 3 is arranged axially close to the planet gear carrier 4. In order to achieve the smallest possible axial distance, a recess 33 for the sun gear 13 is introduced locally in the guide support of the planet gear carrier 4.

The permanent positional fixing of the planet gear bolt 21 of the multi-stage planetary gear set 2 is carried out by means of crimping 22, 23 at the two flexible ends of the planet gear bolt 21. The clamping

parts

22, 23 are advantageously arranged distributed over the circumference of the planet gear bolt 21, so that the planet gear bolt 21 is connected to the differential cover 12 or the planet gear carrier 4 in a non-positive and/or positive manner and is rotationally fixed and fixedly secured. For lubricating the rolling

bearings

19, 20 of the spur gears 17, 18 of the multi-stage planetary gear set 2, blind bores 24 are introduced into the planetary gear bolt 21, into which the lubricating oil flows from the side oriented toward the output shaft 16 in the operating state 1 and via the radial bores 25 of the planetary gear bolt 21 into the annular space 26 axially delimited by the rolling

bearings

19, 20.

Fig. 2 and 3 illustrate the arrangement or mounting position of the planetary gear sets 6, 7 of the spur gear differential 3 and the spur gears 17, 18 of the multi-stage planetary gear set 2, which form the gearing, also referred to as double planetary gears, in different views, in order to achieve a compact transmission device 1 in the axial direction. In fig. 2, the planet wheel pegs 21 of the multi-stage planetary gear set 2, which are guided through the meshing plane of the spur gear differential 3, run at a radial distance from the

sun wheels

13, 14 of the spur gear differential 3.

In the detail section of the transmission device 1 according to fig. 4, the installation position of the compensating wheel pin 10 and the lubrication of the compensating

wheels

8, 9 of the spur gear differential 3 are shown in particular. In the mounted state, the compensating wheel stud 10 is inserted into a blind hole 27 of the planet carrier 4 and is fixed axially on the opposite side at a radially inward edge 28 of the differential cover 12. In order to selectively apply lubricating oil to the bearing 29 of the compensating wheel 8, which is designed as a plain bearing, an oil sump 31 is inserted into the longitudinal bore 30 of the compensating wheel pin 10 on the end side. The lubricant contained by the oil pan 31 is guided into the longitudinal bore 30, which is then supplied to the bearing arrangement 29 via the radial bores 32 of the planet gear pegs 10.

Description of the reference numerals

1 Transmission device

2-stage planetary gear set

3 spur gear differential

4 planetary gear carrier

5 casing

6 planetary gear set

7 planetary gear set

8 compensating wheel (Wide)

9 compensating wheel (narrow)

10 compensation wheel bolt

11 compensating wheel bolt

12 differential cover

13 sun gear

14 sun gear

15 output shaft

16 output shaft

17 spur gear

18 spur gear

19 rolling bearing

20 rolling bearing

21 planetary gear bolt

22 crimping part

23 crimping section

24 blind hole

25 radial hole

26 annular space

27 blind hole

28 edge

29 support device

30 longitudinal hole

31 oil pan

32 radial holes

33 recess

34 floating bearing

35 running toothing

36 fixed bearing

37 accommodating part

38 shoulder

39 input sun gear

The spacing of the S spur gears.

Claims

1. A transmission device for a motor vehicle, comprising a multi-stage planetary gear set (2) and a spur gear differential (3) which are connected via a common planet carrier (4) and which have a first and a second planetary gear set (6, 7) which mesh with one another in pairs, wherein each planetary gear set (6, 7) comprises a sun gear (13, 14) which is rotationally fixedly connected to an output shaft (15, 16) of the spur gear differential (3), a torque which is introduced via an input shaft into a transmission device (1) which is integrated in a housing (5) being transmitted from the multi-stage planetary gear set (2) into the spur gear differential (3) and subsequently onto the output shafts (15, 16) for transmission to driven wheels, wherein the plane of mesh of the multi-stage planetary gear set (2) and at least one of the spur gear differentials (3) are too large The male wheels (13, 14) are radially overlapped,

it is characterized in that the preparation method is characterized in that,

the compensating wheel pins (10, 11) of the multi-stage planetary gear set (2) are guided at a radial distance from the sun wheels (13, 14) through the meshing plane of the spur gear differential (3) and fix the differential cover (12) radially and axially on the end side, and the planet carrier (4) is supported in the housing (4) via a floating bearing (34) which is obtained by the tooth engagement of the input sun wheel (39) of the multi-stage planetary gear set (2) and the spur gear (17) forming a double planetary gear and on the opposite side by means of the differential cover (12) via a fixed bearing (36).

2. A transmission arrangement according to any one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the sun gear (13) of the spur gear differential (3) is arranged at a small axial distance from the planet carrier (4) in the installed state, said planet carrier having a recess (33) in each case in the region of the compensating wheel bolts (10, 11).

3. A transmission arrangement according to any one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the outer enveloping circle of the spur gear differential (3) is designed to be smaller than the inner diameter of the gear ring.

4. A transmission arrangement according to any one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the compensating wheel bolts (10, 11) of the spur gear differential (3) are fixed in the mounted state in a form-fitting manner at least axially via the component geometries of the differential cover (12) and of the planet carrier (4).

5. A transmission arrangement according to any one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the planet gear pins (21) of the multi-stage planetary gear set (2) are fixed in position at both ends by means of a crimp (22, 23) with the planet gear carrier (4) or the differential cover (12).

6. A transmission arrangement according to any one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

spur gears (17, 18) of the multi-stage planetary gear set (2) are rotatably mounted on the planetary gear pin (21) via rolling bearings (19, 20).

7. A transmission arrangement according to any one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

in order to lubricate the bearing (29) of the compensating wheels (8, 9) of the spur gear differential (3), an oil sump (31) is inserted into the longitudinal bore (30) of the compensating wheel pins (10, 11) at the end.

8. A transmission arrangement according to any one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

for lubricating rolling bearings (19, 20) of spur gears (17, 18) of the multi-stage planetary gear set (2), the planetary gear pin (21) has a blind bore (24) and a radial bore (25).

9. A transmission arrangement according to any one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

in order to produce the toothing of the compensating wheels (8, 9) of the spur gear differential (3) and/or of the spur gears (17, 18) of the multi-stage planetary gear set (2), powerful scraping teeth are provided.

10. A transmission arrangement according to any one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the transmission device (1) is used in a powertrain of an E-axle.