CN107791834B

CN107791834B - Drive device for a motor vehicle

Info

Publication number: CN107791834B
Application number: CN201710762118.1A
Authority: CN
Inventors: R.彼得森; J.莫克尔
Original assignee: Volkswagen AG
Current assignee: Volkswagen AG
Priority date: 2016-08-30
Filing date: 2017-08-30
Publication date: 2020-11-27
Anticipated expiration: 2037-08-30
Also published as: DE102016216315A1; CN107791834A

Abstract

The invention relates to a drive for a motor vehicle, comprising a transmission device, the output shaft of which is connected to a planetary differential having a ring gear, a sun gear and a planet carrier as its second output shaft, two sets of first and second planet gears being rotatably arranged on the planet carrier, the first planet gears meshing with the ring gear and the second planet gears, the second planet gears meshing with the first planet gears and the sun gear, the sun gear being supported by a first of two axle flange shafts which are coaxial with respect to the central axis of the differential and axially spaced from one another, the second axle flange shaft being connected to the planet carrier. The invention is characterized in that the planet carrier (208) supports a first bypass spur gear (216) which meshes with a first bypass pinion (216) fixed to a parallel shaft (220) arranged parallel to the central axis (222) of the differential, the parallel shaft (220) extending below the transmission device (100) extending between the two axle flange shafts (214,230) and supporting a second bypass pinion (224) which meshes with a second bypass spur gear fixed to the second axle flange shaft.

Description

Drive device for a motor vehicle

Technical Field

The invention relates to a drive device for a motor vehicle, comprising a transmission device, the transmission output shaft of which is connected to a differential with two differential output shafts which are coaxial relative to the central axis of the differential and which are connected to axle flange shafts which are axially spaced apart from one another, wherein at least one gear stage is included in at least one connection between an output shaft and the respective axle flange shaft.

Background

Such a drive is known from DE 2010004228 a 1. This document discloses a bevel gear differential arranged coaxially within an electric motor. The axle flange shafts are arranged radially offset with respect to the differential output shaft and are each connected to the latter via a gear stage. This embodiment does not allow an inline installation of the transmission device, which is represented here by an electric machine, in a motor vehicle. The term "transmission device" is to be understood further in the context of the present description and also includes, in particular, a pure transmission as well as embodiments comprising an integrated transmission unit and drive unit, for example an electric machine.

From DE 102014209038 a1 a drive is known, which comprises a transversely oriented transmission device in a motor vehicle, which is connected to the outer face teeth of a planetary differential via a double gear stage realized on an intermediate shaft. The sun shaft carrying the sun gear of the planetary differential transitions to or is identical to the axle flange shaft on the right. The planet carrier of the planetary gear differential transitions to or is identical to the axle flange shaft on the left side. The two axle flange shafts are thus coaxial with respect to the (imaginary) differential central axis, i.e. with respect to the differential rotational axis about which the sun gear, the planet carrier and the ring gear rotate during operation. The two axle flange shafts are spaced slightly apart from one another in the axial direction, i.e. at a slight distance from one another, which separates their ends at the sun gear or the planet carrier.

The differential central axis is parallel to a transmission central axis of the transmission device. The transmission device is disclosed in the patent document as a manual transmission, in which a torque converter and an internal combustion engine are functionally connected to the manual transmission.

This solution does not offer the possibility of an in-line installation of the drive device and the transmission device in the motor vehicle. In particular, it is necessary for the transmission components to extend into the region which is occupied in the known embodiment by the axle flange shaft in a transmission device of complex construction with its own electric machine. In the case of mutually perpendicular rotational axes of the differential and the transmission device, it is also not possible to achieve a coaxial penetration, for example by means of a complex stepped hollow shaft.

It is known from EP1510365a1 to allow the axle flange shafts, which are directed coaxially with respect to the central axis of the differential, to end up in a wheel gear mechanism, which (not disclosed in detail) is adapted to displace the axis of rotation of the wheels above the central axis of the differential, in order to sink the vehicle bottom.

Disclosure of Invention

The object of the invention is to develop such a drive with a transmission device suitable for in-line installation in a motor vehicle.

The above-mentioned object is achieved by a drive device for a motor vehicle, in which a first output shaft of a differential is identical to a first axle flange shaft, a second output shaft of the differential carries a first bypass spur gear, which meshes with a first bypass pinion, which is fastened to parallel shafts arranged parallel to the central axis of the differential, and which extend below a transmission device projecting between two axle flange shafts and carry a second bypass pinion, which meshes with a second bypass spur gear fastened to the second axle flange shaft.

The invention is based on the idea that the axle flange shaft is connected asymmetrically to the differential. When the first axle-flange shaft is identical to the first differential output shaft, the second axle-flange shaft is coupled via two spur gear stages and a parallel shaft, so that it is not of continuous design, although it is arranged coaxially with respect to the differential central axis. This results in a free space which is virtually penetrated by the central axis of the differential and into which a transmission device oriented perpendicularly to the central axis of the differential can project. The transmission device is bypassed by parallel shafts which, in the installed state in the motor vehicle, preferably extend below the transmission device.

In a particularly preferred embodiment, it is provided that the differential is a planetary gear differential having a ring gear, a sun gear and a planet carrier as its second output shaft, on which planet carrier two sets of first and second planet gears are arranged so as to be rotatable, wherein the first planet gear meshes with the ring gear on the one hand and with the second planet gear on the other hand, and the second planet gear meshes with the first planet gear on the one hand and with the sun gear on the other hand, and wherein the first axle flange shaft carries the sun gear and the planet carrier carries the first bypass spur gear. In other words, the first axle flange shaft is designed as a sun shaft supporting the sun gear, the second axle flange shaft is clearly separated from the differential in the axial direction, and the second axle flange shaft must be arranged coaxially with respect to the first axle flange shaft, wherein the connection to the planet carrier is not designed coaxially with the differential central axis, but rather by means of parallel shafts. The parallel shafts are connected at their first ends to the planet carrier via a first gear stage. The planet carrier in particular supports a first bypass spur gear which meshes with a corresponding first bypass pinion on the parallel shaft. The second bypass pinion gear meshes with a corresponding second bypass spur gear on the second axle flange shaft, returning to the level of the differential central axis through the second bypass pinion gear on the other end of the parallel shaft. The advantage of the design of the differential as a planetary differential is the particularly compact design in the direction of the central axis of the differential.

The mutually perpendicular central axes of the transmission device and the differential do not need to be at the same height in the final mounted state. Especially in the case of transmission devices with a large diameter, this can lead to the parallel shafts being displaced too far downwards, which can be unduly impaired by the ground clearance at the bottom of the motor vehicle. In a preferred embodiment, it is therefore provided that the transmission central axis is arranged at a distance from the differential central axis, although perpendicular thereto. In other words, the transmission device projects with only a lower section into the free space formed by the bypass gear stage and the parallel shaft.

The differential is always functionally connected downstream of the transmission device, as is known to those skilled in the art. However, this does not necessarily mean a spatial arrangement of two elements. In particular, it is possible for the transmission device to be farther in the direction of its transmission center axis than the differential. And the transmission output shaft is mounted at a great axial (with reference to the transmission device) or radial (with reference to the differential) distance with respect to the differential. In practice, however, this often happens because the position of the differential is fixed as an important reference point for the chassis design, so that complex and high-performance transmission arrangements, especially in the form of hybrid drive transmission arrangements, can extend far towards the middle of the vehicle. In a further development of the invention, it is therefore provided that the transmission output shaft is connected to a first end of a coupling shaft, which is arranged parallel to the transmission device and at the level of the central axis of the differential, and which carries a bevel gear on its second end, which meshes with an external toothing of the ring gear, preferably in the form of disk-shaped teeth. In other words, a "return" of the torque at the transmission output onto the planetary differential is achieved. The coupling shaft required here can be designed particularly short and therefore less susceptible to vibrations if it supports a bevel gear on its differential-side end, which is engaged centrally with the ring gear of the planetary differential, which ring gear is designed externally as a ring gear. On the input side, the coupling shaft can be connected to the transmission output shaft in different ways, for example via spur gear stages. Of course, bevel gear-disk toothing is also conceivable here.

Advantageously, the two bypass spur gears on the one hand and the two bypass pinion gears on the other hand each have the same number of teeth. This means that the two gear ratios achieved are exactly balanced with respect to one another on the bypass path, so that the planet carrier of the differential rotates at exactly the same rotational speed as the second bypass pinion on the axle flange shaft. In this case, the bypass pinion is significantly smaller in diameter than the bypass spur gear in view of the ground clearance.

It has been found to be particularly advantageous to design a planetary differential with a fixed carrier ratio of +2 with a fixed transmission ratio of (standby ü bersetzenung) + 2. A positive gear ratio is required for achieving the same rotational direction of the axle flange shafts. The transmission ratio value 2 ensures (in unloaded operation) an even distribution of the torque on the two axle flange shafts.

In a preferred further development of the invention, it is provided that the pairs of teeth of the first bypass spur gear and the first bypass pinion on the one hand and the pairs of teeth of the second bypass spur gear and the second bypass pinion on the other hand have respective tooth flanks which are opposite one another. The resulting axial forces acting on the parallel shafts thereby cancel each other out. This greatly simplifies the support of the parallel shafts. What is particularly needed is only one radial support parallel to the shaft. This is preferably done at both ends of the parallel axes. This means that the parallel shafts are provided with radial bearings, in particular roller bearings, at each of their ends. Such a bearing will essentially only withstand radial forces. As mentioned above, the axial forces acting on the parallel shafts are not axial forces, since they are offset by the opposing helical teeth of the bypass gear stage.

Since the diameter is preferably different between the bypass spur gear and the bypass pinion, there will be higher rotational speeds on the parallel shafts. The parallel axes are therefore susceptible to radial vibrations. In order to avoid radial vibrations or to reduce them to an acceptable extent, it is provided in a further development of the invention that the parallel shafts are also supported in the middle, in particular radially. Needle bearings can be used for this purpose, which are particularly advantageous in terms of radial installation space.

Drawings

Other features and advantages of the present invention will be apparent from the following detailed description and the accompanying drawings. In the drawings:

figure 1 shows a front cut-away view cut through a differential/cut through a cross section of a transmission device of a drive device according to the invention,

figure 2 shows a cross section of the differential of figure 1 taken along the cut line II-II,

fig. 3 shows a partially cut-away view of the drive according to the invention, with the internal structure hidden.

The same reference numbers in the drawings identify the same or similar elements.

Detailed Description

Fig. 1 shows a sectional view through an embodiment of a drive device 10 according to the invention, wherein the sectional plane corresponds to a cross section through a transmission device 100 oriented longitudinally in a motor vehicle and to a main section through a differential 200 arranged perpendicularly thereto.

The transmission arrangement 100 comprises an electric machine with a stator 102 and a rotor 104, within which a mechanical transmission 106 is arranged, the details of which are not important in the context of this description.

On the right side of the transmission device 100, a differential 200 is arranged, the differential 200 being configured as a planetary gear differential. Planetary differential 200 includes a ring gear 202, which ring gear 202 supports, in addition to its inner teeth 204, outer teeth 206 in the form of a disk gear. The outer teeth 206 are coupled to an output shaft of the transmission device 100 in a manner to be described further below. The torque distributed by differential 200 is thus directed through outer teeth 206 of ring gear 202.

The planetary differential 200 also includes a planet carrier 208 that supports two sets of

planet gears

210a, 210 b. Fig. 2 shows a cross section through the differential 200 along section line II-II in fig. 1, in particular in fig. 2, the first planet gears 210a meshing with the internal teeth 204 of the ring gear 202 and with the second planet gears 210 b. The second planet gears also mesh with the sun gear 212 of the planetary differential 200. Sun gear 212 is fixed to a first axle flange shaft 214 (on the right).

According to the invention, the planet carrier 208 supports a first bypass spur gear 216, the first bypass spur gear 216 being fixedly positioned with a first bypass pinion 218 on a first end (on the right) of a parallel shaft 220. The parallel shafts 220 extend parallel to the differential central axis 222 and (in the installed state) below the transmission device 100. The parallel shaft 220 supports a second bypass pinion 224 on a second (left) end thereof, which meshes with a second bypass spur gear 228. Spur gear 228 is fixed to a (left) second axle flange shaft 230. In this way, a portion of the torque introduced into the differential 200 is guided to the second axle flange shaft 230 while spatially bypassing the transmission device 200, wherein a free space is created between the axle flange shafts 214,230, into which the transmission device 100 projects. The formation of this free space thus enables a longitudinal arrangement of the transmission device 100.

The bypass spur gears 216, 228 and the bypass pinions 218, 224 have helical teeth, wherein the tooth ramps are designed such that the axial forces respectively generated and acting on the parallel shafts 220 cancel each other out. In this way, a purely radial support of the parallel axes is achieved. For this purpose, roller bearings 232 are respectively associated with the two ends of the parallel shaft 220. The parallel shafts 220 are again supported radially in the middle by means of needle bearings 234. Radial vibrations of the rapidly rotating parallel shaft 220 are damped or reduced by the needle bearing 234.

Fig. 3 shows the connection of the differential 200 to the transmission device 100 in a partially cut-away and partially hidden view. In the transmission device 100, only the stator 102 and the rotor 104 of the electric machine and the transmission output shaft 108 are shown, to which an output pinion 110 is fixed. The output pinion 110 is connected to an input pinion 302 of the coupling shaft 300 through an intermediate pinion 112. The coupling shaft 300 supports, at its differential-side end, an output-side bevel gear 304, which meshes with the external toothing of the ring gear 202 of the differential 200 in the form of a disk gear.

The embodiments discussed in the specific description and shown in the drawings are, of course, merely illustrative examples of the invention. The present description teaches those skilled in the art the possibility of designing from a wide variety of variations. Those skilled in the art can adjust the details of the transmission device 100 as the situation requires, among other things.

List of reference numerals

10 drive device

100 transmission device

102 stator

104 rotor

106 speed changer

108 output shaft of speed changer

110 output pinion

112 intermediate pinion

114 central axis of the transmission

200 planetary gear differential mechanism

202 ring gear

204 internal teeth of a ring gear

206 outer teeth of ring gear

208 planet carrier

210a, b planet

212 sun gear

214 first axle flanged shaft

216 first bypass spur gear

218 first bypass pinion

220 parallel axis

222 differential central axis

224 second bypass pinion

228 second bypass spur gear

230 second axle flange shaft

232 roller bearing

234 needle roller bearing

300 coupling shaft

302 input pinion of coupling shaft

304 bevel gear coupling shaft

Claims

1. A drive arrangement for a motor vehicle, comprising a transmission arrangement (100), the transmission output shaft (108) of which transmission arrangement (100) is connected to a differential (200) with two differential output shafts (214, 208) which are coaxial relative to a differential central axis (222) and which are connected to axle flange shafts (214,230) which are axially spaced apart from one another, wherein at least one gear stage (216, 218) is included in at least one connection between an output shaft (208) and the respective axle flange shaft (230),

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

the first output shaft of the differential (200) is identical to the first axle flange shaft (214), the second output shaft of the differential (200) supports a first bypass spur gear (216) which meshes with a first bypass pinion (218) which is fixed on a parallel shaft (220) arranged parallel to the differential central axis (222), and the parallel shaft (220) extends below the transmission device (100) projecting between the two axle flange shafts (214,230) and supports a second bypass pinion (224) which meshes with a second bypass spur gear (228) fixed on the second axle flange shaft (230).

2. The drive device as set forth in claim 1,

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

the differential (200) is a planetary gear differential having a ring gear (202), a sun gear (212) and a planet carrier (208) as a second output shaft of the planetary gear differential, on which planet carrier two sets of first and second planet wheels (210a, b) are arranged rotatably, wherein the first planet wheel (210a) meshes on the one hand with the ring gear (202) and on the other hand with the second planet wheel (210b), which planet wheel (210b) meshes on the one hand with the first planet wheel (210a) and on the other hand with the sun gear (212), and wherein a first axle flange shaft (214) supports the sun gear (212) and the planet carrier (208) supports a first bypass spur gear (216).

3. The drive device as set forth in claim 2,

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

the transmission central axis (114) of the transmission device (100) is perpendicular to the differential central axis (222) and is arranged at a distance from the differential central axis (222).

4. The drive device as set forth in claim 3,

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

the transmission output shaft (108) is connected to a first end of a coupling shaft (300) which is arranged parallel to the transmission device (100) and at the level of the differential central axis (222), the coupling shaft (300) carrying, at its second end, a bevel gear (304) which meshes with the outer toothing (206) of the ring gear (202) which is designed as a disk toothing.

5. The drive device as set forth in claim 2,

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

the first bypass spur gear and the second bypass spur gear have the same number of teeth as each other on the one hand, and the first bypass pinion and the second bypass pinion have the same number of teeth as each other on the other hand.

6. The drive device as set forth in claim 5,

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

the fixed gear ratio of the planetary gear differential (200) is + 2.

7. The drive device as set forth in claim 2,

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

the pairs of teeth of the first bypass spur gear (216) and the first bypass pinion (218), on the one hand, and of the second bypass spur gear (228) and the second bypass pinion (224), on the other hand, have corresponding tooth flanks opposite one another, so that the resulting axial forces acting on the parallel shafts (220) cancel one another out.

8. The drive device as set forth in claim 7,

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

the parallel shafts (220) are radially supported on both ends.

9. The drive device as set forth in claim 8,

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

the parallel shafts (220) are radially supported at both ends by roller bearings (232).

10. The drive device as set forth in claim 1,

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

the parallel shafts (220) are supported radially in the middle.

11. The drive device as set forth in claim 10,

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

the parallel shafts (220) are supported radially in the middle by needle bearings (234).