GB2598192A

GB2598192A - Drive Module

Info

Publication number: GB2598192A
Application number: GB2109303.4A
Authority: GB
Inventors: Hölscher Hagen; Schulz Achim; Avery Gary; Spenglar Gerhard; Reichle Tobias
Original assignee: Dr Ing HCF Porsche AG
Current assignee: Dr Ing HCF Porsche AG
Priority date: 2020-07-02
Filing date: 2021-06-28
Publication date: 2022-02-23
Anticipated expiration: 2041-06-28
Also published as: BR102021013063A2; GB2598192B; CN113879109A; GB202109303D0; DE102020117438A1

Abstract

A drive module 1, suitable for a motor vehicle 2, with a transmission 6 arranged between an electric motor 4 and a wheel carrier 5. The transmission 6 has an intermediate shaft having first 7 and second 8 intermediate shaft gearwheels. The electric motor 4 meshes with the first intermediate shaft gearwheel 7 via a drive pinion 11, and the second intermediate shaft gearwheel 8 meshes with an output gearwheel 13. The electric motor 4 is arranged on a housing cover 15, and a hollow spindle 28 is partially mounted on the housing cover 15, with the housing cover 15 being screwed to the wheel carrier housing 16. The output gearwheel 13 has a journal 17 with a thread 18, via which a wheel hub 19 is screwed by an axial nut 20; and a wheel bearing 22 is arranged between the wheel carrier housing 16, the wheel hub 19, and the output gearwheel 13.

Description

Drive module The present invention relates to a drive module for a motor vehicle with an electric motor and a wheel carrier according to the preamble of claim 1.

DE 10 2016 007 496 Al discloses a drive module of the type in question for a motor vehicle with an electric motor and with a wheel carrier for mounting a wheel of the motor vehicle. It is provided here that the wheel carrier is mounted on a machine housing of the electric motor by means of at least one transverse link and acts on io one side on the wheel carrier and on the other side is coupled to a machine housing. This is intended to enable an improved ride comfort owing to a smaller unsprung mass.

DE 10 2010 023 982 Al discloses an axle for a motor vehicle with a transmission device comprising at least two interacting transmission elements, and with an electric motor. A wheel suspension is also provided which comprises at least one wheel hub, which can be driven by the electric motor via the transmission device, and a link element for guiding a wheel of the motor vehicle, wherein the wheel suspension has at least one wheel hub carrier element which is connected to the link element and has, at least in regions, a receiving space in which at least one of the transmission elements is accommodated. This is intended in particular to improve the available construction space conditions.

EP 1 961 602 Al discloses a further drive module for a motor vehicle with an electric 25 motor and a wheel carrier, wherein a coupling is provided between a wheel hub and the electric motor.

EP 2 075 175 B1 discloses a drive unit for a transport vehicle for town traffic, said drive unit having an electric motor which is coupled to a driven wheel via a 30 transmission.

EP 2 737 612 B1 discloses a drive module for a motor vehicle with an electric motor and a planetary transmission.

Disadvantages of the drive modules known from the prior art include the fact that they do not have a transmission between an electric motor and a wheel hub or -if such a transmission is present -they are comparatively complicated and of a large size and, as a result, can be produced only with complexity and expensively.

io The present invention is therefore concerned with the problem of specifying, for a drive module of the type in question, an improved or at least an alternative embodiment that in particular overcomes the disadvantages known from the prior art.

is The invention seeks to overcome or ameliorate the problem by the subject matter of independent claim 1 or provide a useful alternative. Advantageous embodiments of the subject matter of the dependent claims.

The present invention is based on the general concept of providing a drive module which is of a comparatively compact size and which comprises a wheel carrier and also a transmission and an electric motor. Division of the wheel carrier into a wheel carrier housing and a housing cover which is screwed thereto permits an arrangement of the electric motor, the transmission of the intermediate shaft, and the wheel carrier with the output gearwheel, in a manner particularly optimized in terms of construction space, wherein at the same time not only is a compact and simple design, but also a high degree of rigidity possible. According to an aspect of the invention, a transmission with an intermediate shaft which is formed from two intermediate shaft gearwheels is between the electric motor and wheel carrier which is divided into two parts. The electric motor meshes here with the first intermediate shaft gearwheel via a drive pinion, while the second intermediate shaft gearwheel meshes with an output gearwheel. The output gearwheel has a journal with a thread, via which a wheel hub are screwed by means of an axle nut. The output gearwheel and the journal are preferably formed integrally here. Also provided is a housing cover on which the electric motor is arranged and to which the intermediate spindle of the intermediate shaft is partially fastened. The housing cover is screwed to the wheel carrier housing, wherein a wheel bearing is arranged at the same time between the wheel carrier housing and the wheel hub and the output gearwheel. The output gearwheel is thus designed in such a manner that, with the aid of the axle nut and the wheel hub, it simultaneously transmits the necessary prestress to the wheel bearing and braces an inner running ring, optionally in a divided design thereof, therebetween. With the drive module according to an aspect of the invention, it is thus possible for the first time to provide a drive module which is optimized in terms of construction space and is of an extremely compact size and in which both the electric motor and the transmission and the wheel bearing are arranged in an extremely compact manner in/on a wheel carrier consisting of the wheel carrier housing and a closing housing cover The wheel hub and the output gearwheel are expediently connected in a torque-transmitting manner via a splined connection. The journal of the output gearwheel is provided with an outer toothing which meshes with an inner toothing of the wheel hub and thus permits transmission of torque. Such a splined connection permits compensation of axial assembly tolerances and also permits high torque transmission capability. Such a splined connection can be designed, for example, in accordance with DIN5480.

In an advantageous development of the solution according to the invention, the wheel bearing is in the form of a two-row ball bearing with a divided inner running ring, an outer running ring and balls arranged in between, wherein the inner running ring is clamped between the wheel hub and the output gearwheel. The outer ring of the wheel bearing is prestressed and fixed, for example, via a fastening plate. For assembly of the wheel bearing, the latter is first of all pressed with the outer running ring into the wheel carrier housing and braced by means of a fastening plate. The wheel hub is subsequently pressed into the inner running ring of the wheel bearing, and the journal of the output gearwheel is pushed from the opposite side into the wheel hub such that it engages annularly in a complementary manner in the wheel hub. Subsequently, in turn, the axle nut is screwed onto the thread of the journal and the wheel hub is thereby braced against the output gearwheel. The inner running ring of the wheel bearing is clamped and fixed here between the shoulders of the wheel hub and the output gearwheel. The output gearwheel is thus centered in relation to the wheel carrier housing via the wheel bearing and not via the splined connection described in the previous paragraph.

io In an advantageous development of the solution according to the invention, the intermediate shaft consisting of two gearwheels which are connected to each other via a torque-transmitting connection is in the form of a hollow shaft and is mounted on a hollow spindle, wherein a screw which is guided through the wheel carrier housing and the hollow spindle and is screwed into the housing cover is provided, via which screw the hollow spindle and indirectly therefore also the intermediate shaft in the form of a hollow shaft is fixed. Such an embodiment affords the great advantage that the above-mentioned screw can be used not only to fix the hollow spindle on the wheel carrier housing, but at the same time also the housing cover on the wheel carrier housing, and therefore the screw simultaneously carries out two functions.

The intermediate shaft is expediently mounted on the hollow spindle via at least one ball bearing and an optionally two-row needle bearing. Axial mounting of the intermediate shaft is possible via the ball bearing, while the needle bearings are pure radial bearings. The ball bearing for mounting the intermediate shaft can be arranged here, for example, below or within the first intermediate shaft gearwheel and can thereby be accommodated in an optimized manner in terms of construction space.

A contact surface between the wheel carrier housing and the housing cover is expediently designed as a flat surface. It is thereby possible to permit sealing between the housing cover and the wheel carrier housing by means of a simple, highly effective and cost-effective seal, such as, for example, a rubber-metal seal, which affords the great advantage of obtaining a comparatively high coefficient of friction via the above-mentioned seal and of thereby reliably preventing undesirable relative movements between the housing cover and the wheel carrier housing.

The wheel carrier housing and the housing cover expediently house the transmission. The wheel carrier housing, which receives the wheel bearing, and the housing cover thus form a common housing, the wheel carrier, for both of the wheel bearing and of the transmission, said wheel carrier being able to accommodate axle io links and spring and damping components, the housing having merely two housing parts, as a result of which not only can the diversity of parts be reduced but at the same time so too can an outlay on assembly. The reduced number of parts also enables bearing and logistic costs to be reduced.

In a further advantageous embodiment of the solution according to the invention, a supporting bearing is provided which mounts the output gearwheel on the housing cover. By means of the supporting bearing, the output gearwheel, which is simultaneously connected to the wheel hub for rotation therewith via, for example, a splined profile, can thus be designed as a multi-part bearing. Accordingly, the output gearwheel can be mounted in relation to the wheel carrier housing via the wheel bearing and in relation to the housing cover via the supporting bearing, thus making it possible in particular to reliably prevent tilting of a wheel axle. This enables a very high camber rate to be achieved since the wheel axle is supported at an axial distance via the wheel bearing and the supporting bearing. In addition, the inner tooth forces are additionally also supported by the supporting bearing.

In a further advantageous embodiment of the solution according to the invention, the drive module is in the form of a premanufactured assembly. This affords the great advantage of being able to premanufacture the complete drive module and of supplying the latter in a premanufactured state to an assembly line for electric or hybrid vehicle, as a result of which the final assembly in the region of the assembly line is significantly simplified and accelerated. In particular, individual preassembly processes can thus also be outsourced. for example to a supplier.

The present invention is furthermore based on the general concept of equipping a motor vehicle, for example an electric or hybrid vehicle, with one or more such drive modules. It is thereby possible to equip such an electric vehicle with, for example, four such drive modules, as a result of which a four-wheel-drive electric vehicle can be produced comparatively simply. Purely theoretically, of course, merely the arrangement of two such drive modules on a front or rear axle of such an electric or hybrid vehicle is also possible, as a result of which in particular a cost-effective io electric vehicle with a reduced requirement for construction space in the region of the drive module can be created. In principle, the drive module according to the invention is also conceivable as a retrofit solution, i.e. is suitable for vehicles with an internal combustion engine which, by retrofitting with the drive module according to the invention, become a hybrid vehicle.

Further important features and advantages of the invention emerge from the dependent claims, from the drawings and from the associated description of the figures with reference to the drawings.

It goes without saying that the features mentioned above and those which have yet to be explained below can be used not only in the respectively stated combination, but also in other combinations or on their own without departing from the scope of the present invention.

Preferred exemplary embodiments of the invention are illustrated in the drawings and will be explained in more detail in the description below, wherein the same reference signs refer to identical or similar or functionally identical components.

In the drawings, in each case schematically, fig. 1 shows a sectional illustration through a drive module according to an embodiment of the invention for a motor vehicle, fig. 2 shows a view of a drive module according to an embodiment of the invention, fig. 3 shows an illustration as in fig. 2, but with a transparent wheel carrier housing and housing cover, fig. 4 shows a view similar to fig. 2, but from an opposite direction, io fig. 5 shows an illustration as in fig. 4, but with a transparent housing cover and electric motor, fig. 6 shows an installation situation of the drive module according to an embodiment of the invention on a motor vehicle according to the invention.

According to figs 1 to 5, a drive module 1 according to an embodiment of the invention for a motor vehicle 2 likewise according to an embodiment of the invention, for example an electric vehicle 3, has an electric motor 4 and a wheel carrier 5 consisting of the wheel carrier housing 16 and the housing cover 15. According to the invention, a transmission 6 with an intermediate shaft 12, consisting of the first intermediate shaft gearwheel 7 and a second intermediate shaft gearwheel 8, is between the electric motor 4 and the wheel carrier 5. The electric motor 4 has, in a known manner, a stator 9 and a rotor 10, wherein a drive shaft of the rotor 10 carries a drive pinion 11. In the mounted state, said drive pinion 11 meshes with the first intermediate shaft gearwheel 7 of the intermediate shaft 12. The second intermediate shaft gearwheel 8, in turn, meshes with a, for example, two-part output gearwheel 13, and therefore the transmission 6 is in the form of a two-stage transmission.

The drive pinion 11 and the first intermediate shaft gearwheel 7 can each have a helical toothing formed in a complementary manner with respect to one another. This is advantageous for compensating for axial forces. In an analogous manner, the output gearwheel 13 and the second intermediate shaft gearwheel Scan also have a complementary helical toothing.

Also provided is the wheel carrier 5 which consists of a wheel carrier housing 16 and a housing cover 15 screwed thereto. The intermediate shaft 12 is indirectly mounted partially, as is the electric motor 4, on the housing cover 15, and receives the supporting bearing 35 of the output gearwheel 13. According to this embodiment of the invention, the output gearwheel 13 has a journal 17 with a thread 18 via which a wheel hub 19 is screwed and thus fixed by means of an axle nut 20. The output gearwheel 13 and the journal 17 are preferably integral. The brake disk 38 and the wheel of a motor vehicle wheel are subsequently screwed to the wheel hub 19.

According to this embodiment of the invention, a wheel bearing 22 is additionally also arranged between the wheel carrier housing 16 and the wheel hub 19 or the output gearwheel 13, said wheel bearing being able to be braced by means of the axle nut 20. The output gearwheel 13 therefore simultaneously is the journal 17 and serves for bracing the wheel bearing 22 (in particular the inner running ring/rings). The outer running ring 24 of the wheel bearing 22 is braced, for example, via a fastening plate which is fixed to the wheel carrier housing 16 via screws; alternatively, a flange design of the outer running ring 24 is likewise possible.

The design according to this embodiment of the invention of the wheel carrier 5 or in general of the drive module 1 makes it possible to provide a drive module 1 of a particularly compact size, wherein the wheel carrier housing 16 and the housing cover 15 not only house the output gearwheel 13 and the wheel bearing 22, but in addition also the transmission 6. The wheel bearing 22 serves here not only for the mounting of the wheel hub 19, but at the same time also for the mounting of the output gearwheel 13, as a result of which separate bearings can be dispensed with.

The wheel bearing 22 here is in the form of a ball bearing and can have one or more inner running rings 23, one or two outer running rings 24, and rolling bodies 25 or balls which are arranged in between and can be held, for example, in a ball carrier cage. The inner running ring 23 and the outer running ring 24 serve here merely as a running surface. In the case illustrated, the wheel bearing 22 has two parallel rows of balls and thereby not only permits particularly smooth mounting of the wheel hub 19 and of the output gearwheel 13, but at the same time also a certain support of a wheel axle 26.

Looking further in particular at fig. 1, it can be seen that the intermediate shaft 12 consisting of two gearwheels 7, 8 which are connected to each other via a torque-transmitting connection is in the form of a hollow shaft and is mounted on a sleeve-like hollow spindle 28, wherein a screw 29 which is guided through the wheel carrier housing 16 and the hollow spindle 28 and is screwed into the housing cover 15 is provided, via which the hollow spindle 28 is fixed. The screw 29 takes on two functions simultaneously here, namely firstly the fixing of the hollow spindle 28, and thereby the mounting of the intermediate shaft 12, and secondly the fixing of the housing cover 15 to the wheel carrier housing 16.

The intermediate shaft 12 is mounted on the hollow spindle 28 via a ball bearing 30 and an optionally two-row needle bearing 31, wherein the ball bearing 30 takes on both a radial mounting and an axial mounting of the first intermediate shaft gearwheel 7 and of the second intermediate shaft gearwheel 8, which both together form the intermediate shaft 12. The needle bearing 31 takes on exclusively a radial bearing function here. The ball bearing 30 is preferably arranged within or below the first intermediate shaft gearwheel 7 and thereby in a manner extremely optimized in terms of construction space. The ball bearing 30 is fixed to the first intermediate shaft gearwheel 7 of intermediate shaft 12 via a fixing element 32, for example a snap ring. The intermediate shaft 12 consisting of the first intermediate shaft gearwheel 7 and the second intermediate shaft gearwheel 8 can be formed in one part here.

A contact surface 33 between the housing cover 15 and the wheel carrier housing 16 is preferably of flat design, which permits comparatively simple sealing with the aid of a rubber-metal seal 34. This makes it possible to achieve the great advantage of preventing relative movements between the housing cover 15 and the wheel carrier housing 16 with the aid of a relatively high coefficient of friction of the rubber-metal seal 34.

The wheel carrier housing 16 and the housing cover 15 house the transmission 6, as 3.0 a result of which separate housing parts can be dispensed with. This also reduces the multiplicity of parts, which in turn contributes to reducing bearing and logistic costs. In addition, the wheel carrier housing 16 is formed by hollow casting, which leads to a comparatively stiff property.

Expediently, a supporting bearing 35 can additionally also be provided which mounts the output gearwheel 13 on the housing cover 15. By means of the fixed connection between the output gearwheel 13 and the wheel hub 19, it is thus possible to mount the output gearwheel 13 both in relation to the wheel carrier housing 16 via the wheel bearing 22 and in relation to the housing cover 15 via the supporting bearing 35, as a result of which in particular tilting of the wheel axle 26 can be avoided. A comparatively high camber rate can thereby be achieved.

In a further advantageous embodiment of the drive module 1 according to the invention, the latter is designed as a premanufactured assembly, which affords the great advantage of premanufacturing said drive module in a preassembly process and of supplying same in the premanufactured state to an assembly line, as a result of which in particular final assembly of the motor vehicle 2 or of the electric vehicle 3 can be positively influenced.

Also looking at fig. 6, it can be seen that the drive module 1 with the electric motor 4 and wheel carrier 5 and also transmission 6 can be arranged in a manner optimized in terms of construction space, in particular with respect to a position between the axle links (36, 37) and the spring and damping components. A brake disk 38 is also placed here onto the wheel hub 19.

Claims

Patent claims 1 A drive module for a motor vehicle with an electric motor and a wheel carrier, wherein - a transmission with an intermediate shaft and a first intermediate shaft gearwheel, which is arranged thereon, and with a second intermediate shaft gearwheel is arranged between the electric motor and the wheel carrier, - the electric motor meshes with the first intermediate shaft gearwheel via a drive pinion, and the second intermediate shaft gearwheel meshes with an output gearwheel, - a housing cover is provided on which the electric motor is arranged and the intermediate shaft is indirectly mounted, - the output gearwheel has a journal with a thread, via which a wheel hub is screwed by means of an axial nut, and -a housing cover which is screwed to the wheel carrier housing is provided, wherein a wheel bearing is arranged between the wheel carrier housing and the wheel hub and the output gearwheel.
2 The drive module as claimed in claim 1, wherein the wheel bearing is in the form of a ball bearing with an inner running ring, an outer running ring and rolling bodies arranged in between, wherein the inner running ring is clamped between the wheel hub and the output gearwheel.
3. The drive module as claimed in claim 1 or 2, wherein the wheel hub and the output gearwheel are connected in a torque-transmitting manner via a splined connection.
4 The drive module as claimed in any one of claims 1 to 3, wherein the intermediate shaft is in the form of a hollow shaft and is mounted on a hollow spindle, wherein a screw which is guided through the wheel carrier housing and the hollow spindle and is screwed into the housing cover is provided, via which screw the hollow spindle is fixed. 5. 6. 9.
The drive module as claimed in claim 4, wherein the intermediate shaft is mounted on the hollow spindle via a ball bearing and a needle bearing.
The drive module as claimed in any one of claims 1 to 5, a contact surface between the wheel carrier housing and the housing cover is designed as a flat surface.
The drive module as claimed in any one of claims 1 to 6, wherein the wheel carrier housing and the housing cover house the transmission.
The drive module as claimed in any one of claims 1 to 7, wherein a supporting bearing is provided which mounts the output gearwheel on the housing cover.
The drive module as claimed in any one of the preceding claims, wherein the drive module is in the form of a premanufactured assembly.
10. The drive module as claimed in any one of the preceding claims, wherein the transmission is sealed with respect to the wheel bearing side via a radial shaft sealing ring on the output gearwheel, said radial shaft sealing ring being mounted in the wheel carrier housing and running on the output gearwheel.
11 The drive module according to claim 2, or any claim dependent thereon, wherein the inner running ring is divided.
12. The drive module according to claim 2, or any claim dependent thereon, wherein the outer running ring is undivided.
13.A motor vehicle with at least one drive module as claimed in any one of the preceding claims.
14.A motor vehicle as claimed in claim 13, the motor vehicle being an electric or hybrid vehicle.