DE102023118565A1 - Geared motor with improved fastening of a stator housing - Google Patents

Abstract

A geared motor (1) with a gearbox (2) and an electric motor (3, 3') connected to it is specified. A stator (13) of the electric motor (3, 3') is frictionally connected to a gearbox housing (4) of the gearbox (2). The motor housing (12) comprises a front housing part (15) arranged on the front side of the stator (13) and a stator housing (16) surrounding the stator (13), the stator housing (16) connecting the gearbox housing (4) and the front housing part (15). The stator housing (16) has axial play (B1, B2) with the gearbox housing (4) and/or the front housing part (15). A vehicle (23) with such a geared motor (1) is also specified.

Description

TECHNICAL FIELD

The invention relates to a geared motor which has a gearbox and an electric motor connected thereto. The gearbox comprises a gearbox housing, and the electric motor comprises a motor housing, a stator arranged in the motor housing and a rotor arranged rotatably in the stator, wherein the rotor is coupled to an input of the gearbox. In addition, the stator is non-positively connected to the gearbox housing. The motor housing comprises a front housing part arranged on the front side of the stator and a stator housing surrounding the stator, wherein the stator housing connects the gearbox housing and the front housing part. The invention further relates to a vehicle with such a geared motor, which is intended to drive the vehicle.

STATE OF THE ART

A geared motor and a vehicle of the type mentioned above are basically known from the state of the art. The problem is that a conventional fastening of the stator housing can lead to thermal stresses due to unequal thermal expansion of the components of the electric motor if different materials are used to build an electric motor. In addition, acting forces can cause deformations, which cause stresses in the stator housing. In these cases, the stator housing must therefore generally have relatively thick walls and be stable, which has a negative impact on material consumption and weight.

DISCLOSURE OF THE INVENTION

An object of the invention is therefore to provide an improved gear motor and an improved vehicle with such a gear motor.

In particular, the material consumption for the stator housing and the weight of the stator housing should be reduced.

• - wobei das Getriebe ein Getriebegehäuse umfasst,
• - wobei der Elektromotor ein Motorgehäuse, einem im Motorgehäuse angeordneten Stator und einen im Stator drehbar angeordneten Rotor umfasst,
• - wobei der Rotor mit einem Eingang des Getriebes gekoppelt ist,
• - wobei der Stator mit dem Getriebegehäuse kraftschlüssig verbunden ist,
• - wobei das Motorgehäuse ein am Stator stirnseitig angeordnetes Stirngehäuseteil und ein den Stator umgebendes Statorgehäuse umfasst,
• - wobei das Statorgehäuse das Getriebegehäuse und das Stirngehäuseteil verbindet und
• - wobei das Statorgehäuse Axialspiel zum Getriebegehäuse und/oder Stirngehäuseteil aufweist.

The object of the invention is achieved with a geared motor which comprises a gearbox and an electric motor connected thereto,

• - wherein the transmission comprises a transmission housing,
• - wherein the electric motor comprises a motor housing, a stator arranged in the motor housing and a rotor rotatably arranged in the stator,
• - wherein the rotor is coupled to an input of the gearbox,
• - whereby the stator is force-locked to the gearbox housing,
• - wherein the motor housing comprises a front housing part arranged on the front side of the stator and a stator housing surrounding the stator,
• - the stator housing connects the gear housing and the front housing part and
• - wherein the stator housing has axial play to the gearbox housing and/or front housing part.

In particular, the stator can be screwed to the gearbox housing. For this purpose, the stator can have through holes running parallel to the rotor axis, through which screws or threaded rods can be guided and thus firmly connect the stator to the gearbox housing. The stator can be attached to the gearbox housing indirectly using the front housing part. In this design variant, the stator lies between the front housing part and the gearbox housing and is clamped when the front housing part is screwed on.

However, it is also conceivable that the stator and front housing part are attached separately, in particular screwed together. For example, the stator can be attached to the gearbox housing and the front housing part to the stator, for example with the help of separate screws.

The same applies to the stator housing as to the stator. This can also be attached in one step when attaching the front housing part.

However, a separate fastening of the stator housing to the front housing part and/or to the gearbox housing, for example with separate screws, is also conceivable in principle.

It is also conceivable that the stator is non-positively connected to the gearbox housing in a way other than with screws, for example via a press connection.

Furthermore, the object of the invention is achieved by a vehicle with a geared motor of the above-mentioned type, which is intended to drive the vehicle.

With the help of the proposed measures, thermal expansion of the stator housing as well as deformations caused by acting forces can be compensated well, resulting in resulting stresses are avoided and the stator housing can therefore be made very thin. This has a positive effect on the material consumption for the stator housing and the weight of the stator housing and is particularly advantageous when the stator housing is not load-bearing.

The front housing part can have a shoulder on a side facing the stator, which serves as a radial (and possibly form-fitting) support surface for the stator housing, but also secures it axially. The shoulder is long enough to accommodate an optional seal, which makes this design particularly suitable for oil-cooled geared motors.

Further advantageous embodiments and developments of the invention emerge from the subclaims and from the description in conjunction with the figures.

It is advantageous if the stator housing is flangeless and in particular is designed as a generally hollow cylindrical body. This makes it very easy to manufacture the stator housing. For example, the stator housing can be manufactured by extrusion, by 3D printing or as a longitudinally welded tube. Extrusion and 3D printing are particularly suitable if the stator housing is made of plastic, with (plastic) extrusion enabling particularly efficient manufacturing. If the stator housing is made of plastic, it is not only efficient to manufacture, but also particularly light. Longitudinal welded tubes can be manufactured by bending a sheet material and then welding it. Above all, but not only, this manufacturing method is suitable for the manufacture of stator housings made of metal. In particular, the proposed measures also enable the length of the stator housing to be easily adapted to different types of electric motors. To do this, a tube with the profile of the stator housing can be produced in a first step and the stator housing can be produced by cutting the tube to length in a second step. For example, tubes several meters long can be manufactured and then cut to length according to the length of the stator housing.

In one embodiment of the geared motor, the stator housing can have a circular, oval, polygonal or star- or gear-like profile in cross-section. In particular, when using a polygonal profile, the screws for fastening the stator to the gear housing can be arranged in the corners of the polygon and thus in particular outside the stator, so that the magnetic field in the stator is not influenced by the screws. Furthermore, this can save electrical sheet metal and thus also save costs and weight. In principle, the screws for fastening the stator to the gear housing can also run inside the stator. As an alternative to the screws, threaded rods that are integrally or detachably connected to the gear housing can also be used to fasten the stator housing to the gear housing.

It is advantageous if the stator housing is at least partially transparent. This allows a view into the interior of the electrical machine and makes it easy to check that it is functioning correctly. The stator housing can be completely transparent or partially transparent, the latter including both viewing windows in an otherwise opaque stator housing and stator housings that are made entirely from translucent materials.

In particular, it is advantageous in the above context if the stator housing is manufactured by means of coextrusion, whereby a first plastic is opaque and a second plastic is at least partially transparent. In this way, a partially transparent stator housing can be manufactured particularly efficiently.

It is advantageous if the stator housing is sealed to the gearbox housing and/or the front housing part. This prevents moisture and dirt from penetrating the interior of the electric motor, and also prevents lubricants and coolants from escaping.

In this context, it is particularly advantageous if the stator housing is radially sealed to the gearbox housing and/or the front housing part. In particular, the seal is then independent of the length of the stator housing, which means that it can be manufactured with large tolerances. In principle, however, an axial seal of the stator housing to the gearbox housing and/or the front housing part is also possible.

For cooling and possibly also lubrication, the geared motor can be equipped with a liquid cooling system, whereby the stator housing is in contact with a cooling liquid. For this purpose, the geared motor can have a coolant line, which serves to cool and possibly lubricate the electric motor and optionally also the gearbox. The coolant line can be For example, it can be connected to an external oil circuit, which can also have an oil cooler. In this context, it is particularly advantageous if the stator housing is at least partially transparent, as this makes it easy to check that the cooling/lubrication is working correctly.

In general, the proposed measures are particularly advantageous when the electric motor is mounted axially on the gearbox and when the gearbox is designed as a T.

The above embodiments and developments of the invention can be combined in any way.

SHORT DESCRIPTION OF THE CHARACTERS

• 1 einen beispielhaften im Längsschnitt dargestellten Getriebemotor;
• 2 einen Querschnitt durch einen Elektromotor mit polygonförmigem Statorgehäuse und
• 3 ein schematisch dargestelltes Kraftfahrzeug mit einem elektrischen Antrieb der vorgeschlagenen Art.

Embodiments of the invention are shown by way of example in the attached schematic figures. They show:

• 1 an exemplary gear motor shown in longitudinal section;
• 2 a cross-section through an electric motor with a polygonal stator housing and
• 3 a schematically illustrated motor vehicle with an electric drive of the proposed type.

DETAILED DESCRIPTION OF THE INVENTION

To begin with, it should be noted that identical parts in the different embodiments are provided with identical reference symbols or identical component designations, possibly with different indices. The disclosure of a component contained in the description can be transferred analogously to another component with the same reference symbol or identical component designation. The position information chosen in the description, such as "top", "bottom", "back", "front", "side" and so on, also refer to the figure directly described and shown and, if the position changes, are to be transferred analogously to the new position.

1 shows a longitudinal section through an exemplary gear motor 1, which comprises a gearbox 2 and an electric motor 3 connected thereto.

The transmission 2 comprises a transmission housing 4, a plurality of (rolling) bearings 5 arranged in the transmission housing 4 and an output shaft 6 rotatably mounted therein and an intermediate shaft 7 rotatably mounted therein. The transmission 2 further comprises a first pinion 8, a first gear 9 engaging therewith, a second pinion 10 and a second gear 11 engaging therewith. The first gear 9 and the second pinion 10 are mounted on the intermediate shaft 7, the second gear 11 on the output shaft 6.

The electric motor 3 comprises a motor housing 12, a stator 13 arranged in the motor housing 12 and a rotor 14 arranged in the stator 13 so as to be rotatable about the rotor axis A. The motor housing 12 has a front housing part 15 arranged on the front side of the stator 13 and a stator housing 16 surrounding the stator 13, the stator housing 16 connecting the gear housing 4 and the front housing part 15. In this example, the stator 13 is screwed to the gear housing 4 using screws 17. In the specific example, the front housing part 15 is also screwed to the stator 13 using screws 17 or, strictly speaking, the stator 13 is clamped between the front housing part 15 and the gear housing 4.

However, it is also conceivable that the stator 13 is connected to the gear housing 4 in another way, for example via separate screws or a press connection.

The proposed measures make it possible in particular for the stator housing 16 to be designed to be non-load-bearing. However, this is not a mandatory feature and the front housing part 15 could also be attached in a different way, or the stator housing 16 could be a load-bearing component.

The stator 13 can have a stator laminated core with a plurality of stator laminates (not shown in detail) and stator magnets or stator windings arranged therein. Similarly, the rotor 14 can have a rotor laminated core with a plurality of rotor laminates (not shown in detail) and rotor magnets or rotor windings arranged therein.

The rotor 14 is mounted on the rotor shaft 18, which is rotatably mounted in the stator 13 with the aid of one of the bearings 5 and with the aid of the (rolling) bearing 19. In this example, the rotor shaft 18 also forms the input shaft of the gearbox 2, on which the first pinion 8 is mounted. In principle, however, two separate but coupled shafts could also be provided for the gearbox 2 and the electric motor 3. In both cases, the rotor 14 is coupled to an input of the gearbox 2. The rotor 14 is also motion-coupled to the output shaft 6 of the gearbox 2 via the pinions 8, 10 and the gears 9, 11. This means that a rotational movement of the rotor 14 is transmitted (in this case at a reduced speed) to the output shaft 6. The Output shaft 6 is in the 1 coaxially to the rotor shaft 18. However, this is not a mandatory requirement, and the output shaft 6 and the rotor shaft 18 could also have a different position relative to one another.

Finally, the gear motor 1 comprises two optional seals 20, 21, with which the stator housing 16 is sealed against the front housing part 15 of the electric motor 3 and against the gear housing 4, respectively. Specifically, in this example, the stator housing 16 is radially sealed against the gear housing 4 and the front housing part 15. In principle, however, an axial seal instead of the radial seal would also be conceivable.

In the embodiment shown, the stator housing 16 has axial play B1, B2 with respect to the gear housing 4 and the front housing part 15. However, it is also conceivable that the stator housing 16 has axial play B1, B2 only with respect to the gear housing 4 or only with respect to the front housing part 15. Advantageously, thermal expansion of the stator housing 16 and deformations due to acting forces can be compensated for well in this way, whereby resulting stresses are avoided and the stator housing 16 can therefore be designed to be very thin. This is particularly advantageous if the stator housing 16 is not load-bearing.

In this example, the stator housing 16 is designed without a flange, which makes it easy to manufacture. In particular, the stator housing 16 can be designed as a generally hollow cylindrical body, which further simplifies its manufacture. For example, the stator housing 16 can be manufactured by means of extrusion, by means of 3D printing or as a longitudinally welded tube. In particular, the stator housing 16 can also be made of plastic. In a particularly advantageous variant, the stator housing 16 is manufactured by means of plastic extrusion.

• - Herstellen eines Zwischenprodukts für ein Statorgehäuse 16, wobei das Statorgehäuse 16 Teil des Motorgehäuses 12 ist, in Form eines allgemein hohlzylindrischen Körpers, der im Querschnitt das gleiche Profil aufweist wie das Statorgehäuse 16, der jedoch länger ist als das Statorgehäuse 16 (insbesondere mehr als zweimal so lange),
• - Herstellen des Statorgehäuses 16 durch Ablängen des Zwischenprodukts,
• - Bereitstellen des Getriebes 2 mit dem Getriebegehäuse 4,
• - Bereitstellen des Stators 13, des Rotors 14 sowie des Stirngehäuseteils 15, das ebenfalls Teil des Motorgehäuses 12 ist,
• - Kraftschlüssiges Verbinden des Stators 13 mit dem Getriebegehäuse 4 (z.B. über eine Verschraubung oder eine Pressverbindung),
• - Koppeln des Rotors 14 mit dem Eingang des Getriebes 2 und
• - Montage des Motorgehäuses 12, wobei das Stirngehäuseteil 15 am Stator 13 stirnseitig angeordnet wird und wobei das Statorgehäuse 16 den Stator 13 umgibt und das Getriebegehäuse 4 und das Stirngehäuseteil 15 verbindet.

A method for producing a geared motor 1 can now comprise the following steps:

• - producing an intermediate product for a stator housing 16, the stator housing 16 being part of the motor housing 12, in the form of a generally hollow cylindrical body which has the same profile in cross section as the stator housing 16, but which is longer than the stator housing 16 (in particular more than twice as long),
• - producing the stator housing 16 by cutting the intermediate product to length,
• - Providing the gearbox 2 with the gearbox housing 4,
• - Providing the stator 13, the rotor 14 and the front housing part 15, which is also part of the motor housing 12,
• - Force-locking connection of the stator 13 with the gear housing 4 (e.g. via a screw connection or a press connection),
• - Coupling the rotor 14 with the input of the gearbox 2 and
• - Assembly of the motor housing 12, wherein the front housing part 15 is arranged on the front side of the stator 13 and wherein the stator housing 16 surrounds the stator 13 and connects the gear housing 4 and the front housing part 15.

• 1) Aufsetzen des Stators 13 auf das Getriebegehäuse 4,
• 2) Einsetzen des Rotors 14 in den Stator 13,
• 3) Überstülpen des Statorgehäuses 16 über den Stator 13,
• 4) Anbringen des Stirngehäuseteils 15 und
• 5) Verschrauben des Stators 13 und des Stirngehäuseteils 15 mit dem Getriebegehäuse 4.

After manufacturing the stator housing 16, providing the gear 2 with the gear housing 4 and providing the stator 13, the rotor 14 and the front housing part 15, the following steps in particular can be carried out in the order given:

• 1) Place the stator 13 on the gear housing 4,
• 2) Inserting the rotor 14 into the stator 13,
• 3) Slipping the stator housing 16 over the stator 13,
• 4) Attach the front housing part 15 and
• 5) Screw the stator 13 and the front housing part 15 to the gear housing 4.

In particular, the proposed measures enable the length of the stator housing 16 to be easily adapted to different types of electric motors 3. To this end, in a first step, a tubular intermediate product with the profile of the later stator housing 16 is produced, and in a second step, the stator housing 16 is produced by cutting the tube to length. The intermediate product can in particular have a length of several meters. The intermediate product for the stator housing 16 can also be produced by extrusion, by 3D printing or as a longitudinally welded tube. In particular, the intermediate product can be made of plastic. In a particularly advantageous variant, the intermediate product can be produced by plastic extrusion.

The stator housing 16 can also be at least partially transparent to allow a view into the interior of the electric motor 3. For example, the stator housing 16 can be produced by means of coextrusion, wherein a first plastic is opaque and a second plastic is at least partially transparent.

Finally, in the example shown, the geared motor 1 comprises an optional and symbolically represented coolant line 22, with the aid of which both the gear 2 and the electric motor 3 are cooled and lubricated. The coolant line 22 can, for example, be connected to an external oil circuit, which can also have an oil cooler. In the example shown, the geared motor 1 is therefore equipped with liquid cooling, with the stator housing 16 being in contact with a coolant. In this context, it is particularly advantageous if the stator housing 16 is at least partially transparent, since in this way the correct functioning of the cooling/lubrication can be easily checked.

In the electric motor 3, the screws 17 are guided through the stator 13. However, this is not the only conceivable possibility. It is also conceivable that the screws 17 are guided outside the stator 13. 2 shows a cross-section through an example electric motor 3'. The hexagonal profile of the stator housing 16 can also be seen from the cross-section, with a screw 17 arranged in each corner of the profile. Other polygonal profiles, circular profiles, oval profiles and star- or gear-like profiles are of course also conceivable, particularly depending on the number and position of the screws. As an alternative to the screws 17, threaded rods that are integrally or detachably connected to the gear housing 4 can also be used to fasten the stator housing 16 to the gear housing 4.

The 3 finally shows the gear motor 1 installed in a vehicle 23. The vehicle 23 has two axles, one of which is driven. Specifically, the gear motor 1 is connected to the half-axles 24 of the rear axle. Finally, the driven wheels 25 are mounted on the half-axles 24. The gear motor 1 and the half-axles 24 are thus part of the drive train of the vehicle 23. The vehicle 23 is driven at least partially or temporarily by the gear motor 1. This means that the gear motor 1 can serve to drive the vehicle 23 alone or, for example, be provided in conjunction with an internal combustion engine (hybrid drive). In the 3 In the example shown, the gear motor 1 is installed parallel to the axis. However, this is not mandatory; the gear motor 1 could also be installed in a different position. Furthermore, the (sole) drive of the rear axle is purely an example, and the gear motor 1 could also drive only the front axle or all wheels 25.

Finally, it is noted that the scope of protection is determined by the patent claims. However, the description and the drawings must be used to interpret the claims. The features contained in the figures can be exchanged and combined with one another as desired. In particular, it is also noted that the devices shown can in reality also comprise more or fewer components than shown. In some cases, the devices shown or their components can also be shown not to scale and/or enlarged and/or reduced.

list of reference symbols

1

gear motor

2

transmission

3, 3'

electric motor

4

gearbox housing

5

(rolling) bearings

6

output shaft

7

intermediate shaft

8

first pinion

9

first gear

10

second pinion

11

second gear

12

engine housing

13

stator

14

rotor

15

front housing part

16

stator housing

17

screw

18

rotor shaft

19

(rolling) bearings

20

seal

21

seal

22

coolant line

23

vehicle

24

semi-axis

25

wheel

A

rotor axis

B1, B2

axial play

Claims (13)

Geared motor (1) comprising a gearbox (2) and an electric motor (3, 3') connected thereto, - wherein the gearbox (2) comprises a gearbox housing (4), - wherein the electric motor (3, 3') comprises a motor housing (12), a stator (13) arranged in the motor housing (12) and a rotor (14) rotatably arranged in the stator (13), - wherein the rotor (14) is coupled to an input of the gearbox (2), - wherein the stator (13) is non-positively connected to the gearbox housing (4), - wherein the motor housing (12) comprises a front housing part (15) arranged on the front side of the stator (13) and a stator housing (16) surrounding the stator (13), and - wherein the stator housing (16) connects the gearbox housing (4) and the front housing part (15), characterized in that - the stator housing (16) has axial play (B1, B2) with respect to the gearbox housing (4) and/or front housing part (15). Gear motor (1) after claim 1 , characterized in that the stator housing (16) is designed without a flange. Gear motor (1) after claim 1 or 2 , characterized in that the stator housing (16) is designed as a generally hollow cylindrical body. Gear motor (1) according to one of the Claims 1 until 3 , characterized in that the stator housing (16) has a circular, oval, polygonal or star- or gear-like profile in cross section. Gear motor (1) according to one of the Claims 1 until 4 , characterized in that the stator housing (16) is made of plastic. Gear motor (1) according to one of the Claims 1 until 5 , characterized in that the stator housing (16) is manufactured by extrusion, by 3D printing or as a longitudinally welded tube. Gear motor (1) according to one of the Claims 1 until 6 , characterized in that the stator housing (16) is at least partially transparent. Gear motor (1) after claim 7 , characterized in that the stator housing (16) is produced by means of coextrusion, wherein a first plastic is opaque and a second plastic is at least partially transparent. Gear motor (1) according to one of the Claims 1 until 8 , characterized in that the stator housing (16) is sealed to the gear housing (4) and/or to the front housing part (15). Gear motor (1) after claim 9 , characterized in that the stator housing (16) is radially sealed to the gear housing (4) and/or to the front housing part (15). Gear motor (1) according to one of the Claims 1 until 10 , characterized in that the stator housing (16) is non-load-bearing. Gear motor (1) according to one of the Claims 1 until 11 , characterized in that the geared motor (1) is equipped with a liquid cooling system and the stator housing (16) is in contact with a cooling liquid. Vehicle (23) with a geared motor (1) according to one of the Claims 1 until 12 which is intended to drive the vehicle (23).

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