DE102021121893A1 - Planet carrier, planetary gear and electric final drive train - Google Patents

Abstract

The invention relates to a planetary gear carrier (60) for accommodating a plurality of rotatably mounted planetary gears (70) within a planetary gear (40), the planetary gears (70) rotating within the planetary gear carrier (60) about a first sun gear (50) of the planetary gear ( 40), wherein the planet carrier (60) has a first radially running end face and a second, axially spaced, second end face (62) running parallel to the first end face (61), which are spaced apart from one another by a plurality of circumferentially distributed axial webs (63). , bearing points (64) for the planet gears (70) being formed in the end faces (61,62), the planet gear carrier (60) being formed from two sheet metal sections (65,66) which are essentially the same part.

Description

The present invention relates to a planetary gear carrier for accommodating a plurality of rotatably mounted planetary gears within a planetary gear, the planetary gears moving within the planetary gear carrier in rotation about a first sun gear of the planetary gear, the planetary gear carrier having a first radially running end face and a second, axially spaced, parallel to the first end face running second end face, which are spaced apart from each other by a plurality of circumferentially distributed axial webs, bearing points for the planet gears being formed in the end faces. The invention relates to a planetary gear and an electric final drive train.

Electric motors are increasingly being used to drive motor vehicles in order to create alternatives to internal combustion engines that require fossil fuels. Significant efforts have already been made to improve the suitability for everyday use of electric drives and also to be able to offer users the driving comfort they are accustomed to.

A detailed description of an electric drive can be found in an article in the ATZ magazine, volume 113, 05/2011, pages 360-365 by Erik Schneider, Frank Fickl, Bernd Cebulski and Jens Liebold with the title: Highly integrative and flexible electric drive unit for electric Vehicles, which is probably the closest state of the art. This article describes a drive unit for an axle of a vehicle, which includes an electric motor that is arranged concentrically and coaxially with a bevel gear differential, with a switchable 2-speed planetary gear set being arranged in the power train between the electric motor and the bevel gear differential, which is also is positioned coaxially to the electric motor or the bevel gear differential or spur gear differential. The drive unit is very compact and allows a good compromise between climbing ability, acceleration and energy consumption due to the switchable 2-speed planetary gear set. Such drive units are also referred to as e-axles or electrically operable drive train.

From the DE 10 2010 048 837 A1 such a drive device with at least one electric motor and at least one planetary differential that can be driven by a rotor of the electric motor is known, the planetary differential having at least one planetary carrier that is operatively connected to a rotor of the electric motor, first planetary gears and second planetary gears that are rotatably mounted on the planetary carrier, and a first sun gear and a second sun gear, each of which is operatively connected to an output shaft of the planetary differential. The first planetary gears mesh with the first sun gear and each of the second planetary gears meshes with the second sun gear and with one of the first planetary gears. Furthermore, the sun gears are arranged coaxially with an axis of rotation of the rotor.

In the DE 10 2016 216 802 A1 another drive device for a motor vehicle is described with a drive machine, which is operatively connected via a drive shaft to a transmission device, comprising a harmonic drive and a differential gear.

It is known in principle to use stepped planetary gears with such planetary gears for E-axes, which have planetary gears with different diameters. In these concepts, for example, three or four stepped planetary gears each mesh with a drive sun and a ring gear fixed to the housing. The stepped planetary gears have a small-diameter planetary gear with a small toothing that meshes with the ring gear and on a second, axially offset plane a larger-diameter planetary gear with a large toothing that meshes with the drive sun. The planetary gears of the stepped planetary gears can, for example, be welded, pressed and also positively connected to the planetary shaft of a planetary gear. This is for example from the DE102016223098B4 or DE102011079695A1 known.

In particular, the planetary gears installed in such electric axles are very demanding in terms of production and assembly and are correspondingly expensive to manufacture and assemble, so that there is a fundamentally ongoing need to simplify production technology of such gear arrangements with a high level of operational reliability required. A further requirement is to design the planetary gears to be particularly compact, since the space available is generally limited.

It is therefore the object of the invention to reduce or completely eliminate the problems known from the prior art and to provide a planetary gear carrier that can be produced inexpensively. It is also the object of the invention to provide a planetary gear for electric axle drive trains that is both compact and inexpensive to produce.

This object is achieved by a planet gear carrier for accommodating a plurality of rotatably mounted planet gears within one Planetary gear, wherein the planetary gears move within the planetary gear carrier in rotation about a first sun gear of the planetary gear, wherein the planetary gear carrier has a first radially running end face and a second, axially spaced, second end face running parallel to the first end face, which are separated from one another by a plurality of circumferentially distributed axial webs are spaced apart, bearing points for the planetary gears being formed in the end faces, the planetary gear carrier being formed from two sheet metal sections which are essentially the same part.

As a result, a planetary gear carrier that can be produced particularly cost-effectively can be provided, which in particular can be formed without metal-cutting production processes.

An electric final drive train of a motor vehicle includes an electric machine and a transmission arrangement, the electric machine and the transmission arrangement forming a structural unit.

In particular, it can be provided that the electric machine and the transmission arrangement are arranged in a common drive train housing. Alternatively, it would of course also be possible for the electrical machine to have a motor housing and the transmission to have a transmission housing, in which case the structural unit can then be effected by fixing the transmission arrangement in relation to the electrical machine. This structural unit is sometimes also referred to as the E-axis.

The electrical machine is intended in particular for use within an electrically operable drive train of a motor vehicle. In particular, the electrical machine is dimensioned in such a way that vehicle speeds of more than 50 km/h, preferably more than 80 km/h and in particular more than 100 km/h can be achieved. The electric motor particularly preferably has an output of more than 30 kW, preferably more than 50 kW and in particular more than 70 kW. Furthermore, it is preferred that the electrical machine provides speeds greater than 5,000 rpm, particularly preferably greater than 10,000 rpm, very particularly preferably greater than 12,500 rpm.

The gear arrangement of the electric axle drive train can be coupled in particular to the electric machine, which is designed to generate a drive torque for the motor vehicle. The drive torque is particularly preferably a main drive torque, so that the motor vehicle is driven exclusively by the drive torque.

The gear arrangement can have a planetary gear and/or a differential gear. A differential gear is a planetary gear with one input and two outputs. It usually has the function of driving two vehicle wheels of a motor vehicle in such a way that they can turn at different speeds in curves, but with the same propulsive force.

According to an advantageous embodiment of the invention, it can be provided that the first end face and the second end face have an essentially triangular outer contour. In principle, it is also possible for the first and second end faces to have a polygonal outer contour, such as square, pentagonal, hexagonal, etc.. The number of polygons particularly preferably corresponds to the number of planetary gears in the planetary gear carrier.

According to a further preferred further development of the invention, it can also be provided that the axial webs each have a contact section pointing radially inwards.

Furthermore, according to a likewise advantageous embodiment of the invention, provision can be made for peripherally adjacent contact sections to rest against one another.

According to a further particularly preferred embodiment of the invention, it can be provided that the circumferentially adjacent contact sections are fixed to one another by means of a rivet connection.

Furthermore, the invention can also be further developed such that the first end face and the second end face have fastening openings through which the contact sections pass.

In a likewise preferred embodiment variant of the invention, it can also be provided that the contact sections are fixed in the fastening openings by caulking. This means that welding can be dispensed with.

It can also be advantageous to further develop the invention in such a way that the number of axial webs formed monolithically on an end face corresponds to the number of planetary gears accommodated in the planetary gear carrier.

The object of the invention is also achieved by a planetary gear, in particular for an electrically operable axle drive train Motor vehicle comprising a planet carrier according to any one of claims 1-8.

Finally, the object of the invention can also be achieved by an electrically operable final drive train of a motor vehicle, comprising an electric machine with a rotor that is rotatably mounted relative to a stator, and a gear arrangement, the electric machine and the gear arrangement forming a structural unit, and the rotor is connected to the transmission arrangement in a torque-transmitting manner, the transmission arrangement comprising a planetary gear with a first sun gear and a plurality of stepped planet gears which mesh with the first sun gear and are rotatably mounted in a planet gear carrier and which rotate about the first sun gear, and a coaxial to the first sun gear arranged ring gear, wherein the planet carrier is formed according to any one of claims 1-8.

The invention will be explained in more detail below with reference to figures without restricting the general inventive idea.

• 1 zwei Blechschnitte eines Planetenradträgers in perspektivischer Ansicht,
• 2 ein Planetenradträger mit zwei Blechschnitten in jeiner Exposionsdarstellung,
• 3 zwei Blechschnitte eines Planetenradträgers in drei verschiedenen Fertigungszuständen in jeweils perspektivischer Ansicht,
• 4 einen bestückten Planetenradträger in einer Querschnittsdarstellung,
• 5 einen Planetenradträger mit Planetenrädern in einer Explosionsdarstellung,
• 6 ein Planetengetriebe in einem schematischen Schaltbild,
• 7 ein Achsantriebsstrang eines Kraftfahrzeugs in einer schematischen Blockschaltansicht.

It shows:

• 1 two sheet metal sections of a planet carrier in a perspective view,
• 2 a planet carrier with two sheet metal sections in each exploded view,
• 3 two sheet metal sections of a planet carrier in three different production stages, each in a perspective view,
• 4 an equipped planet carrier in a cross-sectional view,
• 5 a planet carrier with planet gears in an exploded view,
• 6 a planetary gear in a schematic circuit diagram,
• 7 an axle drive train of a motor vehicle in a schematic block circuit view.

The 2-5 show a planetary gear carrier 60 for receiving a plurality of rotatably mounted planetary gears 70 within a planetary gear 40, as exemplified in FIG 6 is sketched. The planetary gears 70 move within the planetary gear carrier 60 in rotation about a first sun gear 50 of the planetary gear 40.

The planet gear carrier 60 has a first radially running end face and a second, axially spaced, second end face 62 running parallel to the first end face 61, which are spaced apart from one another by a plurality of axial webs 63 distributed around the circumference. Bearing points 64 for the planet gears 70 are formed as circular openings in the end faces 61,62.

As in particular from the 1 is clearly visible, the planetary gear carrier 60 is formed from two sheet metal sections 65, 66 which are essentially the same part. In the embodiment shown, the first end face 61 and the second end face 62 have an essentially triangular outer contour.

The axial webs 63 each have a contact section 67 pointing radially inwards. How particularly good from the 3 As can be seen, these adjacent contact sections 67 rest against one another on the circumference. In order to form the planet carrier 60 from the sheet metal sections 65,66, the sheet metal sections 65,66 have corresponding fold lines around which the axial webs 63 and plant sections 67 are designed to be plastically pivotable. The axial webs 63 are thereby pivoted by about 90 ° to a face 61.62 and the Anlageabschnitte 68 also by about 90 ° to the axial webs 63, so that in the 2 configuration shown.

The number of axial webs 63 formed monolithically on an end face 61, 62 corresponds to the number of planetary gears 70 accommodated in the planetary gear carrier 60; in the example shown, three planetary gears 70 are provided in the planetary gear carrier 60 and correspondingly three axial webs 63 per sheet metal section 65,66. This also goes well from the exploded view of the 5 out.

The claw-like sheet metal cuts 65.66 from the 2 are then put together what's in the 3 is shown. The first end face 61 and the second end face 62 have fastening openings 68 through which the contact sections 67 pass when the sheet metal sections 65, 66 are assembled. The contact sections 67 are then fixed in the fastening openings 68 by caulking. Like in the 4 is shown, the peripherally adjacent contact sections 67 can also be fixed in relation to one another by means of a rivet connection 69 .

The planet carrier 60 is particularly suitable for use in a planetary gear 40, as exemplified in FIG 6 is shown. The planetary gear 40, which is configured in particular for an electrically operable final drive train 1 of a motor vehicle 2, comprising a planetary gear carrier 60, as it is from the 3-5 is known.

The planetary gear 40 can preferably be used in an electrically operable final drive train 1 a motor vehicle 2 are used. The final drive train 1 comprises an electric machine 3 with a rotor which is mounted such that it can rotate relative to a stator 9, and a gear arrangement, with the electric machine 3 and the gear arrangement forming a structural unit. The rotor 10 is connected to the transmission arrangement in a torque-transmitting manner, with the transmission arrangement comprising a planetary gear 40 with a first sun gear 50 and a plurality of planet gears 70 which mesh with the first sun gear 50 and are rotatably mounted in a planet gear carrier 60 and which rotate about the first sun gear 50 move, as well as a ring gear 80 arranged coaxially to the first sun gear 50. The planet gear carrier 60 corresponds to that in FIGS 3-5 shown planet carrier 60.

The invention is not limited to the embodiments shown in the figures. The foregoing description is therefore not to be considered as limiting but as illustrative. The following patent claims are to be understood in such a way that a mentioned feature is present in at least one embodiment of the invention. This does not exclude the presence of other features. If the patent claims and the above description define 'first' and 'second' feature, this designation serves to distinguish between two similar features without establishing a ranking.

Reference List

1

final drive train

2

motor vehicle

3

electric machine

40

planetary gear

50

sun gear

60

planet carrier

61

face

62

face

63

axial webs

64

storage locations

65

sheet metal cutting

66

sheet metal cutting

67

investment section

68

mounting holes

69

rivet connection

70

planet gears

80

ring gear

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 102010048837 A1 [0004]
• DE 102016216802 A1 [0005]
• DE 102016223098 B4 [0006]
• DE 102011079695 A1 [0006]

Claims (9)

Planetary gear carrier (60) for accommodating a plurality of rotatably mounted planetary gears (70) within a planetary gear (40), the planetary gears (70) rotating within the planetary gear carrier (60) about a first sun gear (50) of the planetary gear (40), wherein the planet gear carrier (60) has a first radially running end face and a second, axially spaced, second end face (62) running parallel to the first end face (61), which are spaced apart from one another by a plurality of circumferentially distributed axial webs (63), wherein in the Faces (61,62) bearing points (64) for the planetary gears (70) are formed, characterized in that the planetary gear carrier (60) is formed from two substantially identical sheet metal sections (65,66). Planet carrier (60) after claim 1 , characterized in that the first end face (61) and the second end face (62) have a substantially triangular outer contour. Planetary wheel carrier (60) according to one of the preceding claims, characterized in that the axial webs (63) each have a radially inwardly pointing contact section (67). Planet carrier (60) after claim 3 , characterized in that peripherally adjacent contact sections (67) abut one another. Planet carrier (60) according to any of the preceding claims 3 - 4 , characterized in that the circumferentially adjacent contact sections (67) are fixed to one another by means of a rivet connection (69). a. characterized in that the first end face (61) and the second end face (62) have fastening openings (68) through which the contact sections (67) pass. Planet carrier (60) after claim 5 , characterized in that the contact sections (67) are fixed in the fastening openings (68) by caulking. Planetary gear carrier (60) according to one of the preceding claims, characterized in that the number of axial webs (63) monolithically constructed on an end face (61, 62) corresponds to the number of planetary gears (70) accommodated in the planetary gear carrier (60). Planetary gear (40), in particular for an electrically operable final drive train (1) of a motor vehicle (2), comprising a planet carrier (60) according to one of the preceding claims. Electrically operable final drive train (1) of a motor vehicle (2), comprising an electric machine (3) with a rotor which is rotatably mounted relative to a stator, and a gear arrangement, the electric machine (3) and the gear arrangement forming a structural unit, and the Rotor is connected to the transmission arrangement in a torque-transmitting manner, the transmission arrangement comprising a planetary gear (40) with a first sun wheel (50) and a plurality of stepped planet wheels (70) which mesh with the first sun wheel (50) and are rotatably mounted in a planet wheel carrier (60). Which move in rotation about the first sun gear (50), and a coaxial to the first sun gear (50) arranged ring gear (80), wherein the planet carrier (60) according to one of Claims 1 - 8th is trained.

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