Patent ID: 12249898

BRIEF DESCRIPTION OF THE FIGURES

FIG.1shows a drive device for a vehicle axle of a two-track vehicle. The drive device has an electric machine which, when installed transversely, is arranged axially parallel to the flange shafts3guided to the vehicle wheels. A stator4with a rotor5interacting therewith is arranged in a stator housing2of the electric machine. The rotor shaft6is rotatably mounted in bearing openings on axially opposite housing walls8,9of the stator housing2. The rotor shaft6of the electric machine is connected in a rotationally fixed manner to a transmission input shaft17of a transmission19, for example via a spline. InFIG.1, the transmission19is realized as a two-stage spur gear that drives an axle differential20. InFIG.1, the axle differential20is positioned outside a transmission housing21for reasons of clarity. In fact, the axle differential20can be positioned within the transmission housing21together with the two-stage spur gear.

InFIG.1, the stator4has a plurality of stator windings, of which only two stator windings21are roughly indicated inFIG.1. Each stator winding21has a winding head on both axial sides, which projects into a winding head space27. Each winding head space27is integrated into an electric machine hydraulic circuit E described later, with the help of which the respective winding head space27can be supplied with coolant in order to cool the winding heads of the stator4. In each of the winding head spaces27, a coolant/air mixture moves in a vortex flow around the rotor shaft5, which rotates at high speed.

As shown inFIG.1, the electric machine hydraulic circuit E has a coolant tank35, which is connected to a suction pump37via a suction line. A pressure line leads from the suction pump37to coolant supply lines41,43. By means of the supply line41, coolant is fed into a radially outer circumferential annular gap45. From there, the coolant is guided via radially outer stator channels47to a further annular gap49in the right winding head space27. The two annular gaps45,47are separated from the respective winding head space27via splash rings44. Each of the splash rings44has nozzles46distributed in the circumferential direction, via which coolant (i.e. oil) can be injected into the respective winding head space27.

By means of the supply line43, coolant is guided through the rotor shaft6and passed via a flow connection51into radially inner stator channels53into the right winding head space27. In addition, coolant is projected radially outwards towards the winding heads starting from the flow connection51and starting from the right mouth opening of the radially inner stator channels53.

The two winding head spaces27are separated from one another in a substantially coolant-tight manner in the interior of the stator housing via the stator/rotor arrangement. In order to provide a flow connection between the winding head spaces27, two sloshing channels54,55(FIG.2) are provided, which extend on the outside of the stator housing in the axial direction over the entire axial length of the stator housing. To reduce the total height htot, each of the two sloshing channels54,55is arranged offset from a rotor axis vertical plane V inFIG.2with a transverse offset Δx. In this way, the stator housing height h1partially overlaps with the slosh channel height h2in the electric machine vertical direction z by an overlap amount Δz. The total height htotis therefore reduced by the overlap amount Δz.

InFIG.1, the transmission19is flanged to the left stator housing axial side. An interior of the transmission19and a transmission sump56formed on the transmission bottom are integrated into a transmission hydraulic circuit G. In the transmission hydraulic circuit G, the coolant draining from transmission components collects at a transmission-side suction point A1. The transmission-side suction point A1is connected via a return line67to a transmission return pump58, which returns coolant into the coolant tank35. In addition, a coolant passage60is formed in the housing end wall8of the stator housing2close to the transmission. This connects the winding head space27close to the transmission with the transmission sump56. The coolant passage60is positioned in vertical alignment with the rotor axis R inFIG.1or2. In addition, the rear sloshing channel55in the direction of travel FR is in direct fluidic connection with the transmission sump56via a channel opening61(FIG.2), while the front sloshing channel54relative to the direction of travel FR has no direct connection to the transmission sump56. The two slosh channels54,55are also connected to the winding head space27near the transmission at coolant passages48,50inFIG.2.

As already mentioned, inFIG.1the electric machine is installed transversely parallel to the vehicle axle. InFIG.1, the transmission-side suction point A1is positioned on the left side of the vehicle, while a transmission-remote suction point A2is positioned on the right side of the vehicle. When the vehicle curves to the left, the coolant is displaced via the sloshing channels54,55towards the right suction point A2due to centrifugal force. In contrast, when the vehicle curves to the right, the coolant is displaced via the sloshing channels54,55towards the left suction point A1due to centrifugal force. Therefore, when cornering, the coolant can be reliably returned to the coolant tank35either via the left suction point A1or via the right suction point A2.

On the stator housing axial side remote from the transmission, a transverse channel65is formed on the stator housing base inFIG.4, into which the two slosh channels54,55and the later described return line66open. The transverse channel65establishes a flow connection between the two slosh channels54,55and the winding head space27remote from the transmission. For this purpose, the transverse channel65is connected to the winding head space27remote from the transmission at a coolant passage69. A sieve element64can also be inserted into the transverse channel65, which element filters the coolant flowing through.

InFIG.1, the suction pump37, the transmission return pump58and an electric machine return pump71are components of a multiple pump (combination pump). With such a multiple pump, the individual pumps are driven by a common drive shaft. The common drive shaft is in turn connected to an electric motor that acts as a drive. InFIG.1, all pumps37,58,71are positioned on the left axial side of the stator housing in a space-saving manner. The suction point A2arranged on the stator housing axial side remote from the pump is connected to the electric machine return pump71via the return line66. The return line66is aligned axially parallel to the two sloshing channels54,55in the figures. The stator housing2can preferably be realized as a cast part, on which both the two sloshing channels54,55and the return line66are formed in one piece using the same material.

In order to ensure reliable coolant circulation in different driving operating states, i.e. while cornering and/or uphill driving, it is preferred if the two suction points A1, A2are positioned in a diagonal arrangement with respect to the rotor axis vertical plane V. For this purpose, the transmission-side suction point A1and the channel opening61of the rear slosh channel55as viewed in the direction of travel FR are arranged at the rear and on the left side of the vehicle with respect to the rotor axis vertical plane (FIG.2). In contrast, the suction point A2remote from the transmission (i.e. the mouth opening of the return line66remote from the transmission) is positioned on the right side of the vehicle and at the front in the direction of travel FR (i.e. with respect to the rotor axis vertical plane V) (FIGS.1and4).

LIST OF REFERENCE NUMERALS

2stator housing3flange shafts4stator5rotor6rotor shaft8,9housing walls17transmission input shaft19transmission21stator windings27winding head space35coolant tank37suction pump41,43coolant supply lines44coolant spray rings45annular gap46nozzles47radially outer stator channels48coolant passages49annular gap50coolant passages51flow connection53radially inner stator channels54,55slosh channels56transmission sump58transmission return pump59electric machine return pump60coolant passage61channel opening63transmission interior64sieve element65transverse channel66return line67return line69coolant passage71electric machine return pumpV rotor axis vertical plane54,55slosh channelsR rotor axish1stator housing heighth2sloshing channel heighthtottotal heightΔz overlap amountΔx transverse offsetE electric machine hydraulic circuitG transmission hydraulic circuitA1transmission-side suction pointA2transmission-remote suction pointR rotor axisV rotor axis vertical planeZ tooth meshing point