Patent Publication Number: US-2022239196-A1

Title: Electromotive transmission device

Description:
This application is a national stage completion of PCT/EP2020/065145 filed Jun. 2, 2020 which claims priority from German Application Serial No. 10 2019 208 034.0 filed Jun. 2, 2019. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to an electromotive transmission device for a vehicle, having an electric motor having a stator winding and a rotor, a drive shaft being drivable in rotation by the input shaft of the electric motor via a transmission, wherein the transmission is arranged coaxially with the input shaft, and the electric motor and the transmission are arranged in a housing which is closed at least on the transmission side by a radial end wall, and wherein the stator winding can be cooled by a cooling device. 
     BACKGROUND OF THE INVENTION 
     In such an electromotive transmission device, it is known to surround the stator coil, which is located on the outside, with a spiral channel through which there flows a coolant which absorbs the heat of the stator coil and transports it away. Owing to the spiral channel, the diameter of the housing is increased considerably, so that a large installation space is required for the electromotive transmission device. 
     SUMMARY OF THE INVENTION 
     The object of the invention is to provide an electromotive transmission device of the type mentioned at the beginning which is of simple construction and requires a smaller installation space. 
     This object is achieved according to the invention in that the transmission has an annular carrier component which, abutting the inner side of the radial end wall, is connected to this end wall, wherein there is arranged in the end wall and/or in the annular carrier component a radially circumferential annular channel to which a pressurized oil is supplied, having a plurality of spray outlets arranged distributed around the circumference of the annular channel or a radially circumferential slot-like spray outlet, which are arranged in the annular carrier component and start from the annular channel, wherein the spray jets or the spray jet of the spray outlets are directed at the stator winding and/or at the rotor. 
     As a result of this simply constructed configuration, no substantial installation space is required for the cooling device, since the components thereof are integrated in already existing components of the electromotive transmission device. 
     Since the stator winding is cooled not indirectly, as in the prior art, but directly, a very high power density of the electric motor is achieved. 
     Spray jets can preferably be directed by the spray outlets at an end winding of the stator winding. 
     For greater distribution of the oil and thus an increased cooling action, the spray outlets can have impact plate nozzles by which the spray jets are directed at the stator winding and/or at the rotor. 
     The rotor preferably comprises a rotor winding. 
     The impact plate nozzles preferably generate a cooling oil fan, that is to say a fan-shaped distribution of the spray jets. 
     In a simple configuration, the spray outlets can be formed in the annular carrier component. 
     If the annular channel is formed between the end wall and the annular carrier component, the annular channel can be formed in a simple manner by the carrier component or by the end wall of the annular channel by covering an annular groove in the end wall or in the carrier component. 
     The carrier component can be a planetary carrier of a planetary transmission. 
     In order to generate the pressure of the oil in the annular channel, the annular channel can be supplied with the oil by a pump. 
     The oil can be the transmission oil of a lubrication circuit, so that a separate coolant is not required. 
     For this purpose, there is preferably arranged in the lower region of the housing a drain leading to an oil sump, via which drain the oil can drain off. 
     The electromotive transmission device can be able to be operated either in motor mode or in generator mode or both in motor mode and in generator mode. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       An exemplary embodiment of the invention is illustrated in the drawing and will be described in greater detail hereinbelow. In the drawings: 
         FIG. 1  shows a detail, in longitudinal section, of an electromotive transmission device 
         FIG. 2  shows a side view of a second exemplary embodiment of an electromotive transmission device without the radial end wall. 
     
    
    
     DETAIL DESCRIPTION OF THE INVENTION 
     The electromotive transmission device illustrated in the figures for a vehicle, in particular for a tractor, has in a housing  1  an electric motor  2  and, coaxially therewith, a planetary transmission  3 . 
     The electric motor  2  has a rotor  4  having a rotor winding  5  and a stator  6  having a stator winding  7 . An end winding  8  of the stator winding  7  faces the planetary transmission  3 . 
     The planetary transmission  3  has an annular planetary carrier  9  which has, uniformly distributed over its circumference, for example three radially outwardly directed lugs, at which it is axially connected by means of screws  10  to a radial end wall  11  of the housing  1 . 
     An input shaft  12  of the electric motor  2  is connected to an internal gear  15 . A sun gear  13  of the planetary transmission  3  is connected in a rotationally fixed manner to a rotor  4  and engages into four planet gears  14  which are rotatably mounted on the planetary carrier  9  and in turn engage into the internal gear  15  surrounding the planet gears  14 , which internal gear in turn has an output shaft, not shown. 
     The end wall  11  has on its inner side a radially circumferential, coaxially protruding ring  16 , the end face of which facing the electric motor  2  is formed with an axially and radially inwardly open annular groove  17 . The annular groove  17  is covered axially and radially inwardly by the planetary carrier  9 , so that an annular channel  18  is formed. 
     Starting from the annular channel  18 , spray outlets  19  are formed in the planetary carrier  9  in such a manner that they are distributed evenly in a radially circumferential manner, which spray outlets are directed at the windings of the electric motor  2 . 
     In  FIGS. 1 and 2 , simple spray outlets  19  are arranged on the planetary carrier  9 , while in the exemplary embodiment of  FIG. 3  the spray outlets  19  are provided with impact nozzles  21 . 
     The annular channel  18  can be supplied by a pump, not shown, with pressurized oil, which in the exemplary embodiment of  FIGS. 1 and 2  strikes the end winding of the stator winding  7  via the spray outlets  19  as a spray jet. 
     In the exemplary embodiment of  FIG. 3 , the oil passing through the spray outlets  19  is deflected by the impact nozzles  21  as a spray jet onto the end winding  8  of the stator winding  7 . 
     The oil striking the end winding  8  of the stator winding  7  cools the stator winding  7 , which heats up during operation, and then runs, for example, via a drain, not shown, arranged in the lower region of the housing  1  to an oil sump, in which it can cool for reuse. 
     This device can be operated in motor mode and/or in generator mode. 
     REFERENCE NUMERALS 
     
         
           1  housing 
           2  electric motor 
           3  planetary transmission 
           4  rotor 
           5  rotor winding 
           6  stator 
           7  stator winding 
           8  end winding 
           9  planetary carrier 
           10  screws 
           11  end wall 
           12  input shaft 
           13  sun gear 
           14  planet gears 
           15  internal gear 
           16  ring 
           17  annular groove 
           18  annular channel 
           19  spray outlets 
           21  impact nozzles