DE102012202460A1 - Electromotive gear device with one-piece housing - Google Patents

Abstract

The invention has for its object to propose an electromotive transmission device, which is easily manufactured and at the same time promises high reliability. This object is achieved by an electromotive transmission device 1 for providing a drive torque for a vehicle, comprising an electric motor 26 for generating the drive torque, with a transmission 18 for converting the drive torque, with a motor housing section 12, in which the electric motor 26 is arranged with a Transmission housing section 13, in which the transmission 18 is arranged, with a cooling circuit, wherein the motor housing section 12 forms part of an engine cooling section 20 for cooling the electric motor 26 and the gear housing section 13 forms part of a transmission cooling section 11 for cooling the transmission 18, wherein the motor housing section 12 and the gear housing portion 13 are integrally formed as a common housing 6.

Description

The invention relates to an electromotive transmission device for providing a drive torque for a vehicle having an electric motor for generating the drive torque, with a transmission for converting the drive torque, with a motor housing section in which the electric motor is arranged with a transmission housing section in which the transmission is arranged and a cooling circuit, wherein the motor housing portion forms part of an engine cooling portion for cooling the electric motor and the gear housing portion forms part of a transmission cooling portion for cooling the transmission.

Electromotive transmission devices, such as electric axles, hybrid transmissions, etc., have been used in addition to, or in replacement of, internal combustion engines for providing drive torque to vehicles. Such electromotive transmission devices usually have at least one electric motor and at least one transmission, wherein the torque of the electric motor is converted in the transmission, and is used instead of a driving torque of an internal combustion engine or in addition to this for driving the vehicle.

For example, the document discloses DE 609 235 53 T2 a drive device with a liquid-cooled electric motor and a planetary gear and is probably the closest prior art. The electric motor is arranged in a housing, on the front side of a bearing plate is screwed, which also forms a receiving space for the planetary gear. In the housing cooling channels are introduced, which serve to cool the stator of the electric motor and form a cooling jacket. A cooling circuit is designed so that a coolant is passed through the cooling jacket of the housing and is subsequently directed into the bearing plate. The ring gear of the planetary gear in the bearing plate together with the bearing plate a pumping device for the coolant, so that the coolant is conveyed during a rotation of the ring gear through the pumping device and is circulated in the cooling circuit. The housing and the bearing plate each have interfaces, so that the coolant can pass from the housing to the bearing plate.

Field of the invention

The invention has for its object to propose an electromotive transmission device, which is easily manufactured and at the same time promises high reliability.

This object is achieved by an electromotive transmission device with the features of claim 1. Preferred or advantageous embodiments of the invention will become apparent from the dependent claims, the following description and the accompanying drawings.

In the context of the invention, an electromotive transmission device is proposed which is suitable and / or designed for providing a drive torque for a vehicle. The drive torque may be a main torque such that the electromotive transmission device drives the vehicle without additional motors, it may be a partial torque, wherein the vehicle is driven by a plurality of motors and may be an auxiliary torque, the Drive torque is superimposed on a main drive torque of another motor. The electromotive transmission device is designed in particular as an electrical axle for driving one or two wheels or as part of a hybrid transmission. The vehicle is designed in particular as a passenger car, truck, bus, etc.

The electromotive transmission device includes an electric motor that generates the drive torque. Furthermore, the electromotive transmission device comprises a transmission which converts the drive torque. Implementation may be a translation, reduction, distribution or combination of torques. In particular, the transmission can be designed as a planetary gear, in particular as a differential planetary gear or as a translation planetary gear. The transmission may also represent only a portion of a larger transmission system.

The electromotive transmission device comprises a motor housing section in which the electric motor is arranged, and a gear housing section in which the transmission is arranged.

For cooling the electromotive transmission device or its components, a cooling circuit is provided, wherein the motor housing section forms part of an engine cooling section for cooling the electric motor and the gear housing section forms part of a transmission cooling section for cooling the transmission. In the engine cooling section and / or in the transmission cooling section guide structures for guiding a coolant or portions thereof are arranged. These guide structures can be designed, for example, as cooling channels, bores, etc. The guide structures are formed by the motor housing portion and / or the gear housing portion or at least formed. Especially During operation, the coolant immediately contacts the motor housing section and the gearbox housing section in the region of the engine cooling section or the gearbox cooling section.

In the context of the invention, it is proposed that the motor housing section and the gear housing section are integrally formed as a common housing. In one piece means in particular that the two sections are made of a common semi-finished or that these two sections are urgeformt together and coherently.

The advantage of the invention is the fact that the cooling of the electromotive transmission device by the one-piece design of the motor housing portion and the gear housing portion has a higher reliability because z. B. on the large-scale sealing areas, as these are known for example in the cited prior art, can be dispensed with.

Further, the assembly of the electromotive transmission apparatus is simplified because the motor housing portion and the gear housing portion no longer need to be adjusted to each other, but are formed as a part and can be mounted.

In a preferred embodiment of the invention, the motor housing portion and the gear housing portion are formed as a common housing as a sleeve portion through which a shaft is guided, wherein the electric motor and the transmission are arranged coaxially with the shaft. In this embodiment, on the one hand, the electromotive transmission device can be made very compact and on the other hand, the motor housing section and the gear housing section can be manufactured in a simple manner as a common sleeve section. Due to the configuration as a sleeve portion of this example, in a primitive manufacturing process, for example by die casting, in a simple manner to demould from the tool. In particular, the electric motor and the transmission are arranged in the direction of extension of the shaft successively or next to one another.

In a further development of the invention, the electromotive transmission device on an intermediate bearing plate, which separates a receiving space in the motor housing portion for receiving the electric motor of a receiving space in the gear housing portion for receiving the transmission. The intermediate bearing plate is screwed, for example, to the housing, in particular to the sleeve section. The intermediate bearing plate particularly preferably carries a bearing device which serves for mounting a rotor of the electric motor. In addition to the bearing of the rotor, the intermediate bearing plate for sealing the two receiving spaces to each other, so that in the gear housing section, the transmission can be arranged in an oil bath, whereas the electric motor has a grease lubrication or is formed dry.

In a preferred embodiment of the invention, the sleeve portion is completed on both sides with an outer bearing plate, which are particularly preferably fixed to the housing. Thus, the sleeve portion becomes a carrier of two or even three Lageschilden, namely the two outer bearing shields and the intermediate bearing plate.

Preferably, both outer bearing plates support the shaft. Optionally, this is an outer bearing plate for mounting the rotor. Due to the proposed structural design, the electromotive transmission device is particularly easy to assemble, since the bearing plates can be easily attached to the sleeve portion.

In a preferred structural realization of the invention, the engine cooling section comprises a cooling jacket, which preferably completely surrounds the electric motor in the direction of rotation. In particular, a cooling ring is arranged in the motor housing section, which extends in the extension direction of the shaft and which is mounted on the stator of the electric motor. Particularly preferably, the cooling ring extends over at least 50%, preferably at least 70% and in particular over at least 90% of the length of the stator in the extension direction of the shaft. Particularly preferably, webs or grooves are introduced on the radial outer side of the cooling ring, which define the guide structures for the coolant. By contrast, the motor housing section has a radially inwardly directed hollow cylindrical surface, which together with the cooling ring or the webs or grooves form the guide structures, so that the coolant runs along the hollow cylindrical surface. It is particularly advantageous in this realization that the coolant contacts the motor housing section directly and over a large area, so that heat can be dissipated from the coolant via the motor housing section by means of heat conduction.

In a preferred embodiment of the invention, the transmission cooling section has an oil cooling region, which cools an oil, in particular a lubricating oil, of the transmission. The oil cooling area is thus formed as a heat exchanger, which takes heat from the oil of the transmission and passes it on to the cooling circuit.

Particularly preferably, the gear housing section has an oil sump, which is arranged in the installed position at the lowest point of the gear housing section, wherein the oil cooling area is thermally coupled to the oil sump. In particular, the oil cooling region and the oil sump are arranged adjacent to one another and separated from each other only via a web or a wall of the gearbox housing section.

It is particularly preferred if the oil sump is enclosed by the oil cooling area or the gearbox cooling area in a U-shaped manner. Considering a support plane for the electromotive transmission device, the U-shaped configuration is aligned parallel to this support plane. On the one hand, the U-shaped configuration ensures that the thermal coupling between the oil cooling area and the oil sump is very good. On the other hand, it is ensured by the remaining leg of the "U" that there is sufficient space for a discharge of the oil from the oil sump.

In a particularly preferred structural embodiment, the electromotive transmission device has a separate or additional connection device as a further component, which allows a fluidic connection between the engine cooling section and the transmission cooling section. In particular, the coolant is discharged to the engine cooling section from the common housing, passed through the connecting device and then re-introduced into the transmission cooling section. This embodiment makes it possible to form the common housing comparatively simple and to implement the fluidic connection via the connecting device, which can be used as interfaces between connecting device and engine cooling section or transmission cooling section conventional coupling elements whose reliability and tightness have long been proven. For example, the connecting device may be formed as a hose which can be screwed on one side in the transmission cooling section, in particular in the transmission housing section and on the other hand in the engine cooling section, in particular the motor housing section.

By achieved with the cooling reduction of the oil temperature and the coolant temperature, it is possible to interpret the conventional cooling, so the cooling unit of the vehicle, with a lower power or retrieve less power. Depending on the driving condition of the vehicle, the power reduction contributes to a range extension, since less energy is taken from the energy store. In hybrid vehicles, it contributes directly to CO2 reduction.

Further advantages, effects and features of the invention will become apparent from the following description of a preferred embodiment of the invention and the accompanying figures. Showing:

1 a schematic side view of an electrical axis as an embodiment of the invention;

2 a side view on the other side of the electrical axis in the 1 ;

3 a longitudinal section through the electrical axis with graphically partially suppressed components;

4 an isometric view with graphically partially suppressed components;

5 a bottom view of the electrical axis of the preceding figures.

The 1 shows an electrical axis 1 for driving a vehicle as an embodiment of the invention. The electrical axis 1 has a wave 2 on, which is designed as a so-called "thru-axle" and which serves, one from the electrical axis 1 transmitted drive torque to not shown wheels of the vehicle to transmit. The wave 2 rotates about a main axis of rotation 3 and protrudes with respect to the axial extent of the main axis of rotation 3 on both sides.

The main body of the electrical axis 1 is cylindrical and has at its end on one side a supply flange 4 and on the other side an outer bearing shield 5 on. Between the supply flange 4 and the outer end shield 5 is a housing 6 arranged, which integrally as a sleeve portion between the supply flange 4 and the outer end shield 5 extends. In the presentation in the 1 is also an oil line 8th shown with a concealed oil sump 9 fluidically connected.

The 2 shows the electrical axis 1 in a side view from the other side, unlike the page in the 1 a coolant line 10 it can be seen which, on the one hand, in the housing 6 and on the other hand in a transmission cooling section 11 opens, which will be described later in detail.

The 3 shows a longitudinal section through the main axis of rotation 3 the electrical axis 1 , From this representation it can be seen that the housing 6 in a motor housing section 12 and a transmission housing section 13 divides. Motor housing portion 12 and gear housing section 13 are - as can be seen from the hatching - as the housing 6 integrally connected to each other, ie produced from a common semi-finished or produced in a common original molding process. As already described, the housing is 6 on the side of the gear housing section 13 with the outer end shield 5 completed, on the opposite side is the motor housing section 12 within the supply flange 4 with another outer bearing plate 14 completed, indirectly via the flange 4 or directly on the housing 6 is fixed. Between the motor housing section 12 and the transmission housing section 13 is an intermediate bearing plate 15 arranged. Through the intermediate bearing plate 15 become two separate and liquid-separated receiving spaces in the housing 6 educated.

In the motor housing section 12 or in the receiving space is an only schematically illustrated electric motor 26 arranged, which is a stator 16 and a rotor 17 includes. The rotor 17 is on the intermediate bearing plate 15 and the outer end shield 14 rotatably mounted. In the gear housing section 13 is a likewise only schematically illustrated transmission gear 18 arranged, which is preferably formed as a planetary gear, and which via a hollow shaft 19 with the rotor 17 of the electric motor 26 is coupled, the drive torque from the electric motor 26 converts and the wave 2 drives. The wave 2 is on the other hand in the outer bearing plates 5 and 14 stored. the transmission gear 18 in the transmission housing section 13 is lubricated by an oil, especially by a lubricating oil. Bottom side, the oil accumulates due to gravity in the oil sump 9 ,

The electric motor 26 is by means of a cooling jacket 20 cooled, which together through a cooling ring 21 and the motor housing section 12 is formed. The cooling ring 21 extends in the axial direction to the main axis of rotation 3 over at least 80% of the stator 16 and has webs extending in the direction of rotation 22 on which better in the 4 can be seen, which is an isometric representation of the electrical axis 1 with graphically suppressed areas. The bridges 22 form together with the inner, hollow cylindrical surface of the motor housing section 12 cooling channels 24 as guide structures for a coolant, which in the direction of rotation about the main axis of rotation 3 in the cooling jacket 20 meandering. The coolant, eg, water or a water-glycol mixture, is supplied via a coolant inlet 23 in the area of the supply flange 4 introduced, then runs over the cooling channels 24 revolving around the electric motor 26 and occurs - as in the 2 can be recognized again - by a coolant outlet 25 out of the case 6 out, and then over the coolant line 10 in the transmission cooling section 11 transferred.

The 5 shows a bottom view of the electrical axis 1 in which it can be seen that the coolant from the coolant line 10 in the transmission cooling section 11 is performed and at a coolant outlet 27 exits again. The course of the coolant in the transmission cooling section is illustrated by arrows. The transmission cooling section 11 For example, in the bottom view, a coolant guide has a U-shaped profile, wherein the coolant is introduced at a free leg end of the U, is deflected twice, and leaves the transmission cooling section at the other free leg end of the U again. In the area encompassed by the U-shaped course is the oil sump 9 arranged.

As can be seen from the presentation in the 3 can be seen, the oil sump points 9 a collection area 28 and a drainage area 29 on, with the collection area 28 in the section shown a raised floor to the receiving space in the transmission housing section 13 forms and the drainage area 29 again arranged deeper offset. The oil passes through a collection port 30 , Starting from the receiving space of the gear housing section 13 over the collection area 28 in the drainage area 29 , The transmission cooling section 11 is by a simple wall of the collection area 28 separated, so that a good thermal coupling between the oil and the coolant is achieved. In addition, the drainage area 29 arranged within the U, so that also a good thermal coupling between oil in the drainage area 29 and the coolant in the transmission cooling section 11 given is.

The oil sump 9 is as a molded bulge in the receiving space of the gear housing portion 13 educated. From the oil sump 9 leads the oil line 8th path. The transmission cooling section 11 is also from the base material of the gear housing section 13 molded, wherein transmission cooling section 11 and oil sump 9 only separated by a single wall.

The fluidic connection between the cooling jacket 20 and the transmission cooling section 11 via the coolant line 10 , which by means of a simple and robust screw on both the coolant outlet 25 and at the transmission cooling section 11 is fixed.

Through the one-piece housing 6 and the sturdy separate coolant line 10 The cooling circuit can be constructed simple and robust with few components and a small number of sealing surfaces, so that the assembly is simplified and the performance is robust and prone to interference.

LIST OF REFERENCE NUMBERS

1

 axis

2

 wave

3

 Main axis of rotation

4

 Versorgungsflansch

5

 end shield

6

 casing

7

 empty

8th

 oil line

9

 oil sump

10

 Coolant line

11

 Transmission cooling section

12

 Motor housing portion

13

 Transmission case portion

14

 outer bearing plate

15

 Between end shield

16

 stator

17

 rotor

18

 up gear

19

 hollow shaft

20

 cooling jacket

21

 cooling ring

22

 Stege

23

 Coolant inlet

24

 cooling channels

25

 coolant outlet

26

 electric motor

27

 Coolant outlet

28

 collecting area

29

 drain area

30

 collection port

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been 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.

Cited patent literature

• DE 60923553 T2 [0003]

Claims (10)

Electromotive gear device ( 1 ) for providing a drive torque for a vehicle, with an electric motor ( 26 ) for generating the drive torque, with a transmission ( 18 ) for the implementation of the drive torque, with a motor housing section ( 12 ), in which the electric motor ( 26 ) is arranged, with a transmission housing section ( 13 ), in which the transmission ( 18 ) is arranged, with a cooling circuit, wherein the motor housing section ( 12 ) a part of an engine cooling section ( 20 ) for cooling the electric motor ( 26 ) and the gear housing section ( 13 ) a part of a transmission cooling section ( 11 ) for cooling the transmission ( 18 ), characterized in that the motor housing section ( 12 ) and the gear housing section ( 13 ) as a common housing ( 6 ) are integrally formed. Electromotive gear device ( 1 ) according to claim 1, characterized in that the motor housing section ( 12 ) and the gear housing section ( 13 ) together form a sleeve section through which a shaft ( 2 ), the electric motor ( 26 ) and the transmission ( 18 ) are arranged coaxially with the shaft. Electromotive gear device ( 1 ) according to claim 2, characterized in that the sleeve portion on both sides with an outer bearing plate ( 5 . 14 ) is completed. Electromotive gear device ( 1 ) according to claim 2 or 3, characterized in that in the sleeve section an intermediate bearing plate ( 15 ) is arranged, which a receiving space in the motor housing section ( 12 ) from a receiving space in the gear housing section ( 13 ) separates. Electromotive gear device ( 1 ) according to any one of the preceding claims, characterized in that the engine cooling section comprises a cooling jacket ( 20 ) comprising the electric motor ( 26 ) encloses. Electromotive gear device ( 1 ) according to claim 5, characterized in that in the motor housing section ( 12 ) a cooling ring ( 21 ) is arranged, which together with the motor housing section ( 12 ) the cooling jacket ( 20 ). Electromotive gear device ( 1 ) according to one of the preceding claims, characterized in that the transmission cooling section ( 11 ) comprises an oil cooling section, which is an oil of the transmission ( 18 ) cools. Electromotive gear device ( 1 ) according to claim 7, characterized in that the oil cooling region of the transmission cooling section ( 11 ) with an oil sump ( 9 ) of the transmission ( 18 ) is thermally coupled. Electromotive gear device ( 1 ) according to claim 8, characterized in that the oil sump ( 9 ) from the transmission cooling section ( 11 ) is enclosed in a U-shape. Electromotive gear device ( 1 ) according to one of the preceding claims, characterized by a connecting device ( 10 ), which a fluidic connection between the engine cooling section ( 20 ) and the transmission cooling section ( 11 ).

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