EP-4736296-A1 - STATOR, ELECTRICAL MACHINE AND ELECTRICAL DRIVETRAIN

Abstract

The invention relates to a stator (1) for an electrical machine (2), in particular for an electrical machine (2) within a drivetrain (3) of a motor vehicle (4), the stator comprising a stator body (5) having a multiplicity of stator teeth (6) arranged in circumferentially distributed fashion and stator slots (7) formed between the stator teeth (6) and extending through the stator body (5) in the axial direction, wherein electrical conductors (8) of a stator winding (9) are arranged in the stator slots (7) and emerge from an end face of the stator body (5) and at least form a winding head (10), wherein a cooling fluid (11) can be applied to the winding head (10) during operation of the electrical machine (2) and flows through the stator slots (7), and the stator body (5) has an upper half (12) and a lower half (13) when viewed in the direction of gravity, and a fluid-conducting ring (15) is located on the cylindrical ring-type winding head (10).

Inventors

• Gramann, Patrick
• Kirstein, Nils

Assignees

• Schaeffler Technologies AG & Co. KG

Dates

Publication Date

20260506

Application Date

20240517

Claims (10)

1. 1 . Stator (1) for an electrical machine (2), in particular for an electrical machine (2) within a drive train (3) of a motor vehicle (4), comprising a stator body (5) with a plurality of stator teeth (6) arranged distributed around the circumference and stator slots (7) formed between the stator teeth (6) and extending in the axial direction through the stator body (5), wherein electrical conductors (8) of a stator winding (9) are arranged in the stator slots (7), which emerge from the front side of the stator body (5) at least to form a winding head (10), wherein the winding head (10) can be acted upon by a cooling fluid (11) flowing through the stator slots (7) during operation of the electrical machine (2), and the stator body (5) has an upper half (12) and a lower half (13) viewed in the direction of gravity, characterized in that a fluid guide ring (15) is positioned on the cylindrical ring-like winding head (10). which has a first cylinder ring section-like fluid guide section (16), the outer diameter (17) of which is smaller than the inner diameter (18) of the winding head (10) and which has an axial overlap with the winding head (10) and which further extends in the circumferential direction of the fluid guide ring (15) at least through the upper half (12) of the stator body (5), wherein the fluid guide ring (15) further has a second cylinder ring section-like fluid guide section (19), the inner diameter (20) is larger than the outer diameter (21) of the winding head (10) and which has an axial overlap with the winding head (10) and which further extends in the circumferential direction of the fluid guide ring (15) at least in sections through the lower half (13) of the stator body (5) and has a first fluid passage opening (22) from which cooling fluid (11) can flow out under the effect of gravity.
2. 2. Stator (1) according to claim 1, characterized in that a radially outwardly extending, ring-section-like first wall section (23) is formed on the first fluid guide section (16).
3. 3. Stator (1) according to claim 1 or 2, characterized in that a radially inwardly extending, ring-section-like second wall section (24) is formed on the second fluid guide section (19).
4. 4. Stator (1) according to claim 2, characterized in that a second fluid passage opening (25) is formed on the first wall section (23), via which the cooling fluid (11) can be supplied to a rolling bearing (27) via a fluid path (26).
5. 5. Stator (1) according to claim 4, characterized in that the fluid path (26) is formed in a bearing plate (28) which carries the rolling bearing (27).
6. 6. Stator (1) according to one of the preceding claims, characterized in that a further fluid passage opening (29, 30) is formed on both sides of the first fluid passage opening (22) in the circumferential direction, wherein the flow cross section of the first fluid passage opening (22) is larger than the flow cross sections of the fluid passage openings (29, 30) adjacent in the circumferential direction.
7. 7. Stator (1) according to one of the preceding claims, characterized in that the first fluid guide section (16), the second fluid guide section (19), the first wall section (23) and the second wall section (24) are formed in one piece, in particular monolithically.
8. 8. Stator (1) according to one of the preceding claims, characterized in that the fluid guide ring (15) is formed from a plastic.
9. 9. Electrical machine (2) comprising a stator (1) according to one of the preceding claims and a rotor (34) rotatably mounted relative to the stator (1).
10. 10. Electric drive train (3) of a motor vehicle (4) comprising an electric machine (2) according to claim 9.

Description

stator, electric machine and electric drive train The present invention relates to a stator for an electrical machine, in particular for an electrical machine within a drive train of a motor vehicle, comprising a stator body with a plurality of stator teeth arranged in a circumferentially distributed manner and stator slots formed between the stator teeth and extending in the axial direction through the stator body, wherein electrical conductors of a stator winding are arranged in the stator slots, which emerge from the front side of the stator body at least to form a winding head, wherein the winding head can be acted upon by a cooling fluid flowing through the stator slots during operation of the electrical machine, and the stator body has an upper half and a lower half as viewed in the direction of gravity. The invention further relates to an electrical machine and an electrical drive train. Electric motors are increasingly being used to power motor vehicles in order to create alternatives to combustion engines that require fossil fuels. Considerable efforts have already been made to improve the everyday suitability of electric drives and to offer users the driving comfort they are used to. A detailed description of an electric drive can be found in an article in the magazine ATZ 113th year, 05/2011, pages 360-365 by Erik Schneider, Frank Fickl, Bernd Cebulski and Jens Liebold with the title: Highly integrated and flexible electric drive unit for electric vehicles. This article describes a drive unit for an axle of a vehicle, which includes an electric motor that is arranged concentrically and coaxially to a bevel gear differential, with a switchable 2-speed planetary gear set arranged in the power train between the electric motor and the bevel gear differential, which is also positioned coaxially to the electric motor or the bevel gear differential or spur gear differential. The drive unit is very compact and, thanks to the switchable 2-speed planetary gear set, allows a good compromise between climbing ability, Acceleration and energy consumption. Such drive units are also referred to as e-axles or electrically operated drive trains. In addition to purely electrically operated drive trains, hybrid drive trains are also known. Such drive trains in a hybrid vehicle usually comprise a combination of an internal combustion engine and an electric motor, and enable - for example in urban areas - purely electric operation while at the same time providing sufficient range and availability, especially for cross-country journeys. In certain operating situations, it is also possible to drive the vehicle simultaneously using the internal combustion engine and the electric motor. When developing the electrical machines intended for e-axles or hybrid modules, there is a continuing need to increase their power density, so that the cooling of the electrical machines required for this is becoming increasingly important. Due to the necessary cooling performance, hydraulic fluids such as cooling oils have become the standard in most concepts for removing heat from the thermally stressed areas of an electrical machine. Jacket cooling and winding head cooling are known from the state of the art for cooling electrical machines using hydraulic fluids. While jacket cooling transfers the heat generated on the outer surface of the stator laminated core into a cooling circuit, with winding head cooling the heat is transferred directly to the fluid at the conductors outside the stator laminated core in the area of the winding heads. Further improvements are offered by separately designed cooling channels, which are introduced both into the laminated core of the stator (see e.g. EP3157138 A1 ) and into the slot in addition to the conductors (see e.g. Markus Schiefer: Indirect winding cooling of highly utilized permanent magnet synchronous machines with tooth coil winding, dissertation, Karlsruhe Institute of Technology (KIT), 2017). Concepts are also known in which hydraulic fluid flows directly around the windings in order to increase the power density. Improved cooling with direct contact between hydraulic fluid and conductor in the slot is already known in principle from the state of the art. For example, DE102015013018 A1 describes a solution for electrical machines with single-tooth windings, in which the fluid flows directly around the windings that are wound around the teeth. In this context, so-called direct slot cooling and winding head cooling systems have become known, which can achieve very effective cooling of the electrical conductors by directly flushing a liquid cooling medium in the slots and good heat dissipation from the winding heads by applying the cooling medium to the winding heads. In this case, it is usually necessary to enclose the corresponding winding heads to guide the cooling medium. In the case of stators with direct slot cooling and a non-encapsulated winding head, uniform cooling of the winding h