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DE-102024132647-A1 - Rotor for an electric machine, method for manufacturing such a rotor and electric machine with such a rotor

DE102024132647A1DE 102024132647 A1DE102024132647 A1DE 102024132647A1DE-102024132647-A1

Abstract

The present invention relates to a rotor (1) for an electric machine (2) with a rotor body (5) extending along a longitudinal central axis (3) and arranged on a rotor shaft (4) of the rotor (1), the rotor body (5) having opposing axial end faces (6), at least one of which is associated with a winding carrier (7), on the front face (8) of the winding carrier, facing away from the rotor body (5), winding heads (9) of a rotor winding (10) of the rotor (1) are arranged. Crucially, first cooling tunnels (11) through which a first coolant flow (13) is provided on the front face (8) of the winding carrier (7), and second cooling tunnels (12) through which a second coolant flow (14) is provided within the winding heads (9). The invention further relates to a method for manufacturing such a rotor (1) and to an electric machine (2) comprising such a rotor (1).

Inventors

  • Robert Lepper
  • Rainer Leutenmaier
  • Leonard Lorenz
  • Claudia Meitert
  • Holger Oechslen
  • Michael Rehermann
  • Christoph Schmülling

Assignees

  • MAHLE INTERNATIONAL GMBH

Dates

Publication Date
20260513
Application Date
20241108

Claims (12)

  1. Rotor (1) for an electric machine (2) - with a rotor body (5) extending along a longitudinal central axis (3) and arranged on a rotor shaft (4) of the rotor (1) with opposing axial end faces (6), at least one of which a winding carrier (7) is assigned, on the front face (8) of which winding heads (9) of a rotor winding (10) of the rotor (1) are arranged, characterized in that - on the front face (8) of the winding carrier (7) first cooling tunnels (11) through which a first coolant flow (13) of coolant are provided, - within the winding heads (9) second cooling tunnels (12) through which a second coolant flow (14) of coolant are provided.
  2. Rotor (1) after Claim 1 , characterized in that - the first cooling tunnels (11) extend radially at least in sections, and/or - the second cooling tunnels (12) extend radially at least in sections.
  3. Rotor (1) after Claim 1 or 2 , characterized in that - the first cooling tunnels (11) are designed as axially open slots (16) arranged on the front side (8) of the winding carrier (7), which are at least partially covered on their open sides (17) by the winding heads (9).
  4. Rotor (1) according to one of the preceding claims, characterized in that - the second cooling tunnels (12) of winding layers (40, 41) of a respective winding head (9) are through openings (18).
  5. Rotor (1) according to the Claims 3 and 4 , characterized in that - the winding carrier (7) has on its front side (8) winding receptacles (19) for the winding heads (9), each having a radially oriented receiving base (20) with a base surface (21) pointing away from the rotor body (5), a first support leg (22) projecting beyond the base surface (21) and arranged radially outside the receiving base (20) with a support surface (23) oriented radially inwards and a second support leg (24) projecting beyond the base surface (21) and arranged radially inside the receiving base (20) with an inner leg surface (25) oriented radially outwards.
  6. Rotor (1) after Claim 5 , characterized in that - the winding heads (9) are received in the winding receptacles (19) such that they are supported or wound on first surface sections (26) of the base surfaces (21) and on the support surfaces (23) of the first support legs (22), and the base surfaces (21) have radially inner second surface sections (27) not covered by the winding heads (9), - wherein the winding heads (9) have inner surfaces (28) facing the inner leg surfaces (25) which have obliquely designed side regions (29) with respect to the longitudinal center axis (3), - wherein the first cooling tunnels (11) have first inlet openings (30) for letting in the cooling liquid, which are arranged on the second surface sections (27) of the base surfaces (21), - wherein the second cooling tunnels (12) have second inlet openings (31) for letting in the cooling liquid, which are arranged on the side regions (29) of the inner sides (28) of the winding heads (9) are arranged.
  7. Rotor (1) after Claim 6 , characterized in that - the inner leg surfaces (25) of the second support legs (24) and the inner surfaces (28) of the winding heads (9) form between them collecting funnels (32) for collecting and introducing coolant into the first inlet openings (30) and the second inlet openings (31).
  8. Rotor (1) according to one of the preceding claims in conjunction with Claim 5 , characterized in that - the rotor (1) has at least one balancing disk (33) arranged on the rotor shaft (4), which has an annular wall (34) aligned coaxially with respect to the longitudinal center axis (3), which is arranged radially outside on the first support legs (22) of the winding receptacles (19) and surrounds the first support legs (22) externally, - the first support legs (22) and the annular wall (34) of the balancing disk (33) are radially penetrated by first outlet openings (35) and by second outlet openings (36) arranged at an axial distance from the first outlet openings (35), - wherein the first outlet openings (35) are fluidically connected to the first cooling tunnels (11) and have first outlet openings (37) arranged radially outside on the balancing disk (33) for radially venting the cooling fluid, - wherein the second Outlet openings (36) are fluidically connected to the second cooling tunnels (12) and have second outlet openings (38) arranged radially outside on the balancing disc (33) for radially venting the coolant.
  9. Rotor (1) according to one of the preceding claims, characterized in that - the rotor (1) has winding pins (39) for generating the second cooling tunnels (12) which are arranged in pairs and at a distance from each other within the winding heads (9) and/or within the second cooling tunnels (12).
  10. Method for manufacturing a rotor (1), in particular the rotor (1) according to one of the preceding Claims 1 until 9 , comprising a rotor body (5) extending along a longitudinal central axis (3) and arranged on a rotor shaft (4) of the rotor (1), with mutually opposing axial end faces (6), wherein at least one of the axial end faces (6) is associated with a winding carrier (7) having a front face (8) facing away from the rotor body (5), comprising the following steps: a) forming axially open slots (16) on the front face (8) of the winding carrier (7), b) generating the rotor winding (10) of the rotor (1) by winding an electrically conductive conductor layer by layer onto the rotor (1), 1) wherein at least one single winding layer (40) of the rotor winding (10) is wound onto the rotor (1) so that the slots (16) arranged on the front face (8) of the winding carrier (7) are at least partially separated at their open sides (17) by the at least one single 1) the winding layer (40) are covered, thereby forming first cooling tunnels (11) through which coolant can flow, 2) wherein winding pins (39) are provided to generate second cooling tunnels (12) and are arranged in pairs at a distance from each other on the at least one single winding layer (40), 3) wherein at least one further winding layer (41) of the rotor winding (10) is then wound onto the winding pins (39), wherein the winding pins (39) and the winding layers (40, 41) define through-openings (18) between them, so that second cooling tunnels (12) through which coolant can flow are formed.
  11. Electric machine (2) comprising a rotor (1) which according to one of the Claims 1 until 9 trained or according to Claim 10 is manufactured.
  12. Electric machine (2) according to Claim 11 , characterized by , - a stator (42) with a stator winding (43), - wherein the first outlet openings (37) of the first outlet through-holes (35) and/or the second outlet openings (38) of the second outlet through-holes (36) of the rotor (1) which is rotatable relative to the stator (42) and the stator winding (43) of the stator (42) of the electric machine (2) are arranged radially opposite each other, so that in the intended operation of the electric machine (2) cooling fluid can be sprayed through the first cooling tunnels (11) and the first outlet through-holes (35) as well as through the second cooling tunnels (12) and the second outlet through-holes (36) via the first outlet openings (37) and the second outlet openings (38) onto the stator winding (43) of the stator (42).

Description

The present invention relates to a rotor for an electric machine according to the preamble of claim 1. The invention further relates to a method for manufacturing such a rotor and to an electric machine with such a rotor. A rotor of the type mentioned at the beginning is, for example, from the printed document DE 10 2021 212 152 A1 known. In the intended operation of the aforementioned rotor, current flows through its rotor winding to generate a magnetic rotor field. This causes it to heat up considerably, particularly in the area of its winding heads, which is undesirable due to the risk of overheating and subsequent rotor damage. To reliably keep the temperature of the rotor winding and its winding heads below a critical limit of approximately 180°C, the rotor is typically continuously sprayed with a cooling fluid (so-called direct cooling) using a suitable cooling device, which dissipates the heat from the rotor. The problem is that, despite direct cooling, the waste heat from the winding heads accumulates in areas far from the surface, within the winding heads, which the experts involved also refer to as "hotspots", causing the aforementioned limit temperature to be reached and possibly exceeded first in these areas. The object of the invention is therefore to provide an improved or at least an alternative embodiment of a rotor for an electric machine. In particular, it is intended to demonstrate how the cooling of the winding heads of said rotor can be improved. Furthermore, a method for manufacturing such a rotor and an improved electric machine are to be provided. In the present invention, these problems are solved in particular by the subject matter of the independent claims. Advantageous embodiments are the subject matter of the dependent claims and the description. The first problem mentioned at the outset is solved by a rotor for an electric machine with a rotor body extending along a longitudinal central axis and arranged on a rotor shaft. The rotor body has two opposing axial end faces, at least one of which is associated with a winding carrier. On the front face of this carrier, facing away from the rotor body, are the winding heads of a rotor winding. Improved cooling of the winding heads can be achieved by providing, on the front face of the winding carrier, first cooling tunnels through which a coolant flow passes, and, within the winding heads, second cooling tunnels through which a second coolant flow passes. Thus, each winding head of the rotor winding has two separate cooling tunnels through which coolant flows, allowing waste heat to be efficiently dissipated from the inner areas (i.e., from the aforementioned hotspots) of the winding heads compared to conventional direct cooling. This has the advantage that the cooling of the rotor winding or the winding heads of the rotor winding is significantly improved. The rotor body of the rotor can advantageously be formed from one or more stacks of laminations consisting of individual metallic sheet metal disks stacked on top of each other in the longitudinal center axis. It may also be provided that the winding support is arranged on the rotor shaft and/or on the rotor body. In particular, the winding support may be fixed to the rotor shaft and/or on the rotor body in a rotationally fixed manner. The winding support may, for example, be ring-shaped. In particular, it may be formed by a ring-shaped plate. This plate may have two opposing large sides, one of which forms the front of the winding support and the other forming the rear of the winding support facing the rotor body. Due to its favorable thermal conductivity, the winding support can preferably be made of a metallic material, but it is not limited to such a material. For example, the winding support could alternatively be made of a composite material. The coolant in question can be, in particular, an oil or an oil mixture. The terms "axial" and "radial" used herein are conveniently defined as referring to the longitudinal center axis of the rotor. Furthermore, the expressions used below, such as "radial inside" and "radial outside," also refer to the longitudinal center axis of the rotor. Furthermore, it can be provided that the first cooling tunnels and/or the second cooling tunnels run radially, at least in sections. In other words, the first cooling tunnels and/or the second cooling tunnels are radially aligned. This will The purpose is to ensure that the first and/or second cooling tunnels are radially permeable to coolant during normal rotor operation. This has the advantage that the centrifugal forces acting on the coolant during normal rotor operation can be utilized to accelerate the coolant from the radial inside to the radial outside through the first and/or second cooling tunnels. This allows the coolant to be efficiently transported through the first and/or second cooling tunnels, enabling the rapid dissipation of waste heat from the winding heads. Advantageously, the firs