DE102019121079B3 - Compact gear arrangement with stepped planetary set and spur gear differential - Google Patents

Abstract

The invention relates to a gear arrangement (1) for a motor vehicle, comprising a stepped planetary set (2) and a spur gear differential (3) connected via a common planetary carrier (4), which has a first and a second planetary set (6, 7), which are connected to one another in pairs are toothed, each planetary gear set (6, 7) including a sun gear (13, 14), which is connected in a rotationally fixed manner to an output shaft (15, 16) of the spur gear differential (3), torques introduced into the transmission arrangement (1) via an input shaft from the stepped planetary set (2) are transferred to the spur gear differential (3) and then to the output shafts (15, 16) and thus to driven vehicle wheels, with a toothing plane of the stepped planetary set (2) at least one sun gear (13, 14) of the spur gear (3 ) overlaps radially, with the differential gear pin (10, 11) of the stepped planetary set (2) through a toothing plane of the spur gear differential (3) with a ra dialen distance to the sun gears (13, 14) are guided and at the end a differential cover (12) fix radially and axially and the planet carrier (4) via a floating bearing (34), which is formed from a meshing of an input sun (39) and double planetary spur gears (17) of the stepped planetary set (2) results and is mutually supported by means of the differential cover (12) via a fixed bearing (36) in the housing (4).

Description

Transmission arrangement for a motor vehicle, comprising a stepped planetary set and a spur gear differential connected via a common planet carrier, according to the features of the preamble of claim 1.

The DE 10 2015 214 031 A1 shows a transmission arrangement for a motor vehicle, which comprises a transmission input stage and a differential connected to it via a common planet carrier. The differential, constructed as a spur gear differential, has two planetary sets, the planetary gears of which are toothed with separate sun gears. Furthermore, the two planetary sets of the differential are geared to one another in pairs. The transmission input stage has a drive sun that meshes with a first planetary gear set that is connected to the second planetary gear set in a rotationally fixed manner.

Out EP 2 821 672 A1 a gear arrangement assigned to an electric drive unit is known, comprising a rotor shaft as an input shaft and a differential gear and a planetary gear set, also called a gear input stage, whose sun gear is assigned to the input shaft. The differential gear, designed as a spur gear differential, includes planet gears as differential gears and sun gears as output gears, with an output shaft being assigned to each sun gear. A torque introduced via the input shaft is introduced into the spur gear differential via the stepped planetary set and from there it is transferred to the output shafts and then to the driven vehicle wheels. The input shaft forms a hollow shaft through which one of the output shafts is guided.

The DE 10 2012 208 797 A1 shows a gear combination of a differential gear and an additional planetary stage, the differential gear and the planetary stage having a common planetary carrier composed of several partial planetary carriers in a rotationally fixed manner, a central partial planetary carrier arranged between two partial planetary carriers having holes for receiving planetary gear bearing bolts, with a circular, one of the surface region surrounding the holes and arranged concentrically therewith is incorporated deeply into the material of the central partial planetary carrier.

The DE 10 2011 004 696 A1 Fig. 10 shows a vehicle power transmission device and, more particularly, technology for holding a spring washer fitted and attached to an input shaft in a spring washer recess to prevent slipping of a sun gear of a speed reducer fitted to the input shaft.

The DE 10 2013 225 519 A1 shows a planetary gear, in particular for a motor vehicle, with an input shaft forming a sun gear, with a planet carrier that carries a first set of planet gears and a second set of planet gears, with a first ring gear, which is assigned to the first set of planet gears, with a second ring gear, which is assigned to the second set of planetary gears, with a first locking means, by means of which the first ring gear can be locked, and with a second locking means, by means of which the second ring gear can be locked.

The invention is based on the object of creating a gear arrangement for a drive device which is compact at least in the axial direction and which can be easily installed and implemented at low cost.

This object is achieved by a gear arrangement with the features of claim 1. Preferred and / or advantageous embodiments of the invention emerge from the subclaims, the following description and the attached figures.

According to the invention it is provided that at least one planetary gear pin of the stepped planetary set is or are arranged by a toothing plane of the spur gear at a radial distance from its sun gears and the differential pinion continues to fix a differential cover radially and axially at the end facing away from the stepped planetary. To support the planet carrier, it is provided that it is supported on the drive side of the gear arrangement via the running teeth of the large planet gears as a floating bearing and mutually by means of the differential cover via a fixed bearing in the housing of the gear arrangement.

Due to the concept according to the invention, which includes a radial expansion of the spur gear differential, an axially compact spur gear differential can advantageously be implemented, which at the same time has a positive effect on the required installation space of the entire transmission arrangement. Due to the spur gear differential which is expanded in the radial direction, an overlap occurs at least between the stepped planetary sets and a toothing plane of the spur gear differential. To implement this solution, the planetary gear bolt is axially extended from the stepped planetary set to such an extent that it enables the differential cover to be guided and fixed. The compact concept according to the invention advantageously leads to a desired smaller deformation of the planet carrier, which has a positive effect on the torsional stiffness of the gear assembly.

In addition, this compact design according to the invention enables alternative, cost-effective manufacturing methods such as cold forming processes, for example deep drawing, stamping or extrusion, for individual components of the gear arrangement, which ensure overall improved rigidity even with reduced wall thicknesses.

The mounting of the planet carrier according to the invention includes a floating bearing on the drive side, which results from the meshing engagement of the large double planets with the input sun. On the output side, the differential cover, which is non-rotatably connected to the planetary carrier, is preferably mounted in the gear housing of the gear arrangement via a fixed bearing designed as a deep groove ball bearing.

According to an advantageous embodiment, which underlines the axially compact design of the gear arrangement, according to the invention a sun gear of the spur gear differential is placed close to the planet carrier. In order to achieve the smallest possible axial spacing, a recess is made locally in the guide support structure of the planet carrier near the differential pin, which allows the sun gear to rotate freely.

A preferred structural design of the spur gear differential provides for the outer envelope circle of the spur gear differential to be designed to be smaller than the tip circle of an internal toothing of the associated ring gear. This measure results in a simplified assembly sequence, since there is no need to join the ring gear before assembling the spur gear differential over the planet gears.

According to the invention, the pinion pin of the spur gear differential is axially fixed in a form-fitting manner via the component geometries of the differential cover and the planet carrier in the installed state. The differential gear bolt is preferably inserted with one end side into a blind hole in the planet carrier and with the other end side fitted in a hole in the differential cover and supported on a radially inwardly directed rim of the differential cover. An additional form-fitting and / or material-fitting anti-rotation device can be dispensed with for reasons of cost.

The planet gear bolts of the stepped planetary sets are permanently secured in position by means of caulking at both soft ends of the planet gear bolts. The caulking of the planetary gear pin creates a backlash-free fastening to the differential cover and the planetary carrier, which does not require any additional interference fit of the pin in the planetary carrier.
The caulking results in a permanent connection that can withstand high mechanical requirements, such as vibrations that occur when the gear assembly is in operation.

The gear arrangement includes a lubrication device, with the associated pinion pin or a blind hole or a longitudinal hole closed on one side for installation reasons for targeted lubrication of the rotatably mounted differential gears or spur gears of the spur gear differential and the stepped planetary set. An oil pan is preferably inserted at the end of the differential gear pin of the spur gear. In the operating state, oil or oil mist is absorbed by centrifugal forces within the transmission arrangement via the oil pan, which can also be referred to as a baffle plate and preferably circumferentially connects all planetary gear bolts, then fed into the longitudinal bore and from there fed to the bearing via radial bores in the planetary gear bolt.

The planetary gear bolt assigned to the stepped planetary set preferably forms a partition wall in the middle of the longitudinal bore to form a blind bore so that lubricating oil entering can then flow through radial bores to the axially offset bearings of the spur gears.

Skiving is preferably suitable for producing the toothing of the stepped planetary set and / or the spur gear differential. Skiving is a continuous cutting process for the production of gears. This manufacturing process combines hobbing and shaping through continuous rolling with axial feed and enables the production of internal and external gears. The envisaged power skiving enables a higher cross-axis angle at a greater distance, whereby the tool wear and thus the costs can be reduced. To achieve an overall cost-effective production, the toothings of the stepped planetary set are preferably arranged axially at a distance of at least 6 mm from one another.

The compactly constructed gear arrangement according to the invention, including a spur gear differential and a stepped planetary set, is preferably suitable for the drive train of an electric drive unit of a motor vehicle. For example, it is advisable to couple the gear arrangement to an electric motor in order to form a so-called E-axis. The e-axle is a solution for the electric drive of purely electric vehicles or for hybrid applications. In the case of the e-axle, components such as the motor, axle and gearbox, which are used separately in a conventional design, are combined into one structural unit.

• 1: in einem Längsschnitt eine erfindungsgemäß aufgebaute, ein Stirnraddifferential sowie einen Stufenplanetensatz einschließende Getriebeanordnung;
• 2: in einer dreidimensionalen Ansicht einen Ausschnitt von einem Stirnraddifferential und einem Stufenplanetensatz der Getriebeanordnung gemäß 1;
• 3: in einer Vorderansicht die Planetensätze von dem Stirnraddifferential sowie die Zahnräder von dem Stufenplanetensatz;
• 4: einen Detailschnitt durch das Stirnraddifferential der Getriebeanordnung.

The invention is described in more detail below using an exemplary embodiment shown in three figures. However, the invention is not restricted to the exemplary embodiment shown. It shows:

• 1 : in a longitudinal section a gear arrangement constructed according to the invention and including a spur gear differential and a stepped planetary set;
• 2 : in a three-dimensional view a section of a spur gear differential and a stepped planetary set of the gear arrangement according to 1 ;
• 3 : in a front view, the planetary sets of the spur gear differential and the gears of the stepped planetary set;
• 4th : a detail section through the spur gear differential of the gear assembly.

The following description of the figures of an exemplary embodiment is intended to provide a better understanding of the invention. The same components are provided with the same reference numerals.

In the 1 is a transmission arrangement according to the invention 1 according to a preferred embodiment shown in terms of its structure and the arrangement of individual components, wherein in the 1 not all components of the gear assembly 1 are shown. The transmission arrangement assigned, for example, to a drive train (not shown) of an electric drive of a motor vehicle 1 is divided into a stepped planetary set 2 as well as a spur gear differential 3 . In the stepped planetary set also known as the gear ratio section or reduction stage 2 For example, a drive torque introduced by an electric motor (not shown) is translated or reduced from a high input speed to a low output speed. The converted output torque is then transmitted via the spur gear differential 3 distributed on their output shafts connected to the drive wheels of the motor vehicle. For the stepped planetary set 2 as well as the spur gear differential 3 is a planet carrier 4th provided in a housing 5 the gear arrangement 1 is used.

The planet carrier 4th is on the drive side via, for example, a floating bearing 34 executed interlocking engagement between the entrance sun 39 showing the output shaft 15th enclosing, and the large planetary gears 17th rotatably mounted. The bearing of the planet carrier on the output side 4th takes place via a fixed bearing 36 . For this purpose, a deep groove ball bearing is provided, which is between a receptacle 37 of the gearbox 5 the gear arrangement 1 and a cylindrical, axially protruding extension 38 of the differential cover 12 is used, the torsionally rigid with the planet carrier 4th connected is.

The spur gear differential 3 includes as in 2 shown two planetary sets 6th , 7th with differently dimensioned balance gears, a wide balance wheel 8th and a narrow balance wheel 9 , each on an associated pinion pin 10 , 11 are rotatably mounted, which rotatably in associated bores of the planet carrier 4th as well as a differential cover 12 are used. The differential gears are located radially on the inside 8th , 9 each with a sun gear 13 , 14th toothed, each sun gear 13 , 14th rotationally fixed with an output shaft 15th , 16 connected is.

The stepped planetary set 2 includes transmission gears, with two axially offset, helical and interconnected spur gears, also called planet gears 17th , 18th about rolling bearings 19th , 20th rotatable on a planet gear bolt 21st are stored, which are in engagement with further gears (not shown). As a roller bearing 19th , 20th needle roller and cage assemblies (KZK) are preferred. To achieve cost-effective production, the two differently dimensioned spur gears are offset from one another 17th , 18th arranged at an axial distance of ≥ 6 mm. The stepped planetary set also overlaps 2 or its planet gear pin 21st the sun gears in the installed state 13 , 14th and consequently a gear plane of the spur gear differential 3 . The axially compact design of the gear assembly 1 The toothing plane of the sun gear is underlined 13 of the spur gear differential 3 axially close to the planet carrier 4th placed. In order to achieve the smallest possible axial distance, is in the guide support structure of the planet carrier 4th locally a recess 33 for the sun gear 13 brought in.

Permanently secure the position of the planet gear bolts 21st from the step planetary set 2 takes place by means of caulking 22nd , 23 at both soft ends of the pinion pin 21st . The caulking are advantageous 22nd , 23 over the circumference of the planet gear bolt 21st arranged distributed, whereby the planet gear pin 21st non-positive and / or form-fitting with the differential cover 12 or the planet carrier 4th is connected and secured in a rotational and fixed position. For lubrication of the rolling bearings 19th , 20th of the spur gears 17th , 18th from the step planetary set 2 is in the planet gear bolt 21st a blind hole 24 introduced into the operating state 1 from the to the output shaft 16 directed side lubricating oil flows in and through radial bores 25th of the planet gear bolt 21st in one axial of the rolling bearings 19th , 20th limited annulus 26th entry.

The 2 and the 3 illustrate the arrangement or installation positions of the planetary gear sets in different views 6th , 7th of the spur gear differential 3 as well as the gear teeth forming, also called double planetary gears 17th , 18th of the stepped planetary set 2 to create a gear arrangement that is compact in the axial direction 1 . In the 2 is a through the gear plane of the spur gear differential 3 guided planetary pin 21st from the step planetary set 2 , which is at a radial distance from the sun gears 13 , 14th of the spur gear differential 3 runs.

In the detailed section of the gear assembly 1 according to 4th is in particular the installation position of the pinion gear bolt 10 as well as the lubrication of the differential gears 8th , 9 from the spur gear differential 3 shown. The balance wheel bolt is in the installed state 10 into a blind hole 27 of the planet carrier 4th fitted and mutually axially on a radially inwardly directed rim 28 of the differential cover 12 fixed. For the targeted application of lubricating oil to the bearings designed as plain bearings 29 of the balance wheel 8th is at the end in the longitudinal bore 30th of the differential pin 10 an oil pan 31 used. From the oil pan 31 Lubricating oil absorbed is fed into the longitudinal bore 30th guided, which then via radial holes 32 of the planet gear bolt 10 of storage 29 is fed.

List of reference symbols

1

Gear arrangement

2

Step Planet Set

3

Spur gear differential

4th

Planet carrier

5

casing

6

Planetary set

7th

Planetary set

8th

Balance gear (wide)

9

Balance gear (narrow)

10

Differential pin

11

Differential pin

12

Differential cover

13

Sun gear

14th

Sun gear

15th

Output shaft

16

Output shaft

17th

Spur gear

18th

Spur gear

19th

roller bearing

20th

roller bearing

21st

Planet gear bolts

22nd

Caulking

23

Caulking

24

Blind hole

25th

Radial bore

26th

Annulus

27

Blind hole

28

Board

29

storage

30th

Longitudinal bore

31

Oil pan

32

Radial bore

33

Recess

34

Floating bearing

35

Running gear

36

Fixed bearing

37

admission

38

approach

39

Input sun gear

S.

Distance between the spur gears

Claims (10)

Transmission arrangement (1) for a motor vehicle, comprising a stepped planetary set (2) and a spur gear differential (3) which is connected via a common planetary carrier (4) and has a first and a second planetary set (6, 7) which are geared to one another in pairs, wherein each planetary gear set (6, 7) includes a sun gear (13, 14) which is connected in a rotationally fixed manner to an output shaft (15, 16) of the spur gear differential (3), via an input shaft to the gear arrangement (1) integrated in a housing (5) ) Introduced torques are transmitted from the stepped planetary set (2) to the spur gear differential (3) and then to the output shafts (15, 16) and thus to driven vehicle wheels, characterized in that at least one planetary gear pin (21) of the stepped planetary set (2) by a The toothing plane of the spur gear differential (3) protrudes and is or are arranged at a radial distance from the sun gears (13, 14) and the compensation Calibration wheel bolts (10, 11) at the end facing away from the stepped planets (17, 18) fix a differential cover (12) radially and axially, the planet carrier (4) via a floating bearing (34), which is made up of a tooth engagement of an input sun ( 39) and double planetary spur gears (17, 18) of the stepped planetary set (2) results as well is mounted in the housing (5) by means of the differential cover (12) via a fixed bearing (36). Gear arrangement (1) according to Claim 1 characterized in that a sun gear (13, 14) of the spur gear differential (3) is placed in the installed state at a small axial distance from the planet carrier (4), which for this purpose has a recess (33) locally in the area of the differential gear bolts (10, 11) . Gear arrangement (1) according to one of the preceding claims, characterized in that an outer enveloping circle of the spur gear differential (3) is designed to be smaller than an inner diameter of an associated ring gear. Gear arrangement (1) according to one of the preceding claims, characterized in that the differential gear bolts (10, 11) of the spur gear differential (3) are positively fixed in the installed state via the component geometries of the differential cover (12) and the planetary carrier (4) at least axially. Gear arrangement (1) according to one of the preceding claims, characterized in that the planet gear bolts (21) of the stepped planetary sets (2) are fixed in position at both ends by means of caulking (22, 23) with the planet carrier (4) or the differential cover (12). Gear arrangement (1) according to one of the preceding claims, characterized in that the spur gears (17, 18) of the stepped planetary sets (2) are rotatably mounted on the planetary gear pin (21) via roller bearings (19, 20). Gear arrangement (1) according to one of the preceding claims, characterized in that for the lubrication of a bearing (29) of the differential gears (8, 9) of the spur gear differential (3) at the end in a longitudinal bore (30) of the differential gear bolts (10, 11) an oil pan ( 31) is inserted. Gear arrangement (1) according to one of the preceding claims, characterized in that for the lubrication of the roller bearings (19, 20) of the spur gears (17, 18) of the stepped planetary set (2), the planet gear bolts (21) have a blind hole (24) and radial bores (25) exhibit. Gear arrangement (1) according to one of the preceding claims, characterized in that a skiving is provided to produce the toothing of the differential gears (8, 9) of the spur gear differential (3) and / or the spur gears (17, 18) of the stepped planetary set (2). Drive train of an electric axle with a gear arrangement (1) according to one of the preceding claims.

Images