COOLING CHANNEL FOR A WINDING OVERHANG OF A STATOR, AND STATOR COMPRISING A COOLING CHANNEL OF THIS TYPE

Abstract

The invention relates to a cooling channel for a winding head of an electric machine, where the cooling channel is formed to be annular for guiding a cooling fluid with at least one inflow and at least one outflow and for being arranged around the winding head. With the aim of an improved sealing property, the cooling channel comprises an axially movable pressing member which is arranged such that a cooling fluid can flow onto the pressing member and a pressing force against the cooling channel can be generated.

Claims

1. Cooling channel for a winding head of an electric machine, where said cooling channel is formed to be annular for guiding a cooling fluid with at least one inflow and at least one outflow and for being arranged around said winding head, wherein said cooling channel comprises an axially movable pressing member which is arranged such that a cooling fluid can flow onto said pressing member and a pressing force can be generated against said cooling channel.

2. Cooling channel according to claim 1, wherein said inflow or said outflow are configured as an annular gap, where said inflow and said outflow are separated from one another by said pressing member as an annular ceiling section of said cooling channel.

3. Cooling channel according to claim 1, wherein said cooling channel comprises a plurality of partition walls and at least some of said plurality of partition walls are arranged ray-like and form radial partition walls.

4. Cooling channel according to claim 1, wherein at least some of said plurality of partition walls comprise insulation rings arranged concentrically and parallel to one another.

5. Cooling channel according to claim 1, wherein said cooling channel is formed to be multi-part.

6. Cooling channel according to claim 5, wherein said cooling channel comprises a sealing mat as the base component and a stator cooling housing as the outer side wall.

7. Cooling channel according to claim 5, wherein said pressing member, as an outer part of said cooling channel, is configured to be moved toward an oppositely disposed outer part of said cooling channel such that connecting regions between wall parts of said cooling channel are compressed more.

8. Stator, in particular for an electric motor, with a plurality of rod conductors, where said stator comprises at least one cooling channel according to one of the preceding claims and said partition walls are arranged between at least some of said rod conductors.

9. Stator according to claim 8, wherein said stator comprises a plurality of connecting webs corresponding to said rod conductors.

10. Electric machine comprising a cooling channel according to claim 1.

11. Method for (axially) attaching and sealing a cooling channel, where said cooling channel (viewed axially) has a walled upper side and underside, wherein said wall of said cooling channel is supported mechanically on one side and fluidically on the other side.

12. Cooling channel according to claim 1, wherein said inflow and said outflow are configured as an annular gap, where said inflow and said outflow are separated from one another by said pressing member as an annular ceiling section of said cooling channel.

13. Cooling channel according to claim 12, wherein said cooling channel comprises a plurality of partition walls and at least some of said plurality of partition walls are arranged ray-like and form radial partition walls.

14. Cooling channel according to claim 13,

Description

[0036] The figures described below relate to preferred embodiments of the cooling channel according to the invention and of the stator according to the invention, where these figures do not serve as a restriction but essentially to illustrate the invention. Elements from different figures but with the same reference symbols are identical; therefore, the description of one element from one figure is also valid for elements with the same designation or the same number from other figures, where

[0037] FIG. 1 shows a cross-sectional view onto an electric machine;

[0038] FIG. 2 shows a cross-sectional view through a cooling channel according to a preferred embodiment;

[0039] FIG. 3 shows an exploded view of a stator according to the invention with two winding heads and cooling channels;

[0040] FIG. 4 shows a stator with a cooling channel according to the present invention and with fluid flows and pressing forces drawn in; and

[0041] FIG. 5 shows a longitudinal sectional view through an upper part of a stator, in particular its winding head with a cooling channel according to the invention, where fluid flows and pressing forces have been drawn in.

[0042] FIG. 1 shows a cross-sectional view of an electric machine 10 with a stator 1 and a rotor 13 arranged within the stator. Stator 1, in particular laminated stator core 2, is hollow-cylindrical and comprises a respective annular cooling channel 11 and 12 at each end. Cooling channels 11, 12 are connected to a fluid reservoir (not shown) for cooling winding heads 3, 4 formed or arranged in the cooling channels by way of a fluid (see arrows, one pointing inwardly and one pointing outwardly. Rotor 13 is formed by a rotor shaft 14 and a laminated rotor core 15, where the rotor can comprise, for example, permanent magnets, a short-circuit cage, or a current-excited winding, depending on the configuration. Electric machine 10 (and therefore stator 1 and rotor 13) is configured to be rotationally symmetrical about axis of rotation 23.

[0043] FIG. 2 shows a greatly simplified cross-sectional view through a cooling channel 11 or 12 according to a preferred embodiment which is arranged on and attached to a laminated stator core 2 of a stator 1, where the embodiment is explained using a composite winding by way of example. Instead of the composite winding, however, other winding types such as pull-in windings, concentrated windings, or composite windings without interconnection webs (known for example made of Flairpin windings) with correspondingly configured winding heads are also possible.

[0044] The cylindrical laminated stator core 2 comprise a plurality of elongate notches or slots in which a plurality of rod conductors (not shown) is arranged in parallel and concentric about axis of rotation 23. Stator 1 itself is formed in a housing, in particular in a fluid housing 48 with a cylindrical outer wall 50 and an annular cover 51. Cooling channel 11 substantially comprises a cover unit or cover 21 with an inner ring 22 or a cylindrical inner wall 22 as well as an annular sealing mat 45. Cover 21 there functions as a pressing member that presses downwardly with a corresponding external pressure or inner ring 22 as well as vertical partition walls (not shown) of cover 21 against sealing mat 45 and thereby improves the sealing property of the cooling channel. The sealing mat is formed integrally and is preferably made of elastic and/or compressible material. In combination with fluid housing 48 and laminated stator core 2, cover 21 forms a first annular chamber 16 and a second annular chamber 17 of the cooling channel. The interconnection webs (not shown) of the winding head are arranged in the annular chamber 16 and interconnected with the rod conductors. In addition, first annular chamber 16 is fluidly accessible only via annular gap inflow 25 and annular gap outflow 26. First annular chamber 16 is formed by outer wall 50, inner ring 22, cover 21, and sealing mat 45. Sealing mat 45 serves as a base/wall for first chamber 16 or for the cooling channel and comprises openings or recesses through which the rod conductors can project from laminated stator core 2 into first chamber 16. In addition, sealing mat 45 seals laminated stator core 2 against the cooling channel. Second annular chamber 17 is defined and formed by cover 21, outer wall 50, and cover 51 and is arranged above first annular chamber 16. Two chambers 16 and 17 are connected to one another via annular gap inflow 25. Furthermore, an inflow opening 27 is formed in the cover through which a fluid can flow from the outside into second chamber 17. The filled arrows on cover 21 describe the pressing forces. The arrows that are not filled show the fluid flow from the outside into second chamber 17, then into first chamber 16, and subsequently to the exterior.

[0045] FIG. 3 shows an exploded view of a stator 1 according to the invention with a winding composed of rod conductors and interconnection webs which form two annular or cylindrical winding heads 3 and 4 and cooling channels. Stator 1 is equipped with a laminated core 2, in the slots or slot region 29 of which formed on the inside rod conductors 6 and 6a are arranged concentrically about axis of rotation 23. Winding head 3 is arranged on one side for connecting rod conductors 6 and 6a at one end to respective interconnection webs 9. Other winding head 4 is arranged on the other side of laminated core 2 and differs from first winding head 3 in that it comprises an additional interconnection plane 7 with phase connection(s) 8. First winding head 3 therefore comprises four interconnection planes 5 and second winding head 4 comprises four interconnection planes 5 and an interconnection plane 7 with phase connection(s) 8. Both winding heads 3 and 4 are arranged one above the other with a sealing mat 45, an adapter piece 47, four interconnection planes 5 with corresponding interconnection webs 9, or with three groups of interconnection webs 40 composed of five interconnection webs 9. Each interconnection plane 5 or 7 is arranged in its own insulation ring 32 which comprises corresponding slots or partition walls in which interconnection webs 9 are arranged and held. Interconnection webs 9 are arc-shaped rod conductors with rod conductors which additionally extend radially to the axis of the stator and the function of which is to electrically connect rod conductors 6 in pairs. Rod conductors 6 and 6a are connected to one another according to a predetermined pattern, for which reason the distance or the number of interconnection webs 9 between rod conductors 6 and 6a connected in pairs is predetermined. A cover element 21 is provided as the termination of stator 1 and comprises an inner ring 22 and perpendicularly arranged radial partition walls 31. Interconnection planes 5 and 7 are all arranged perpendicular to axis of rotation 23 of stator 1, whereas rod conductors 6 are arranged parallel to this axis. Axis of rotation 23 describes the axis of a rotor (not shown) that can be inserted into stator 1 and at the same time serves to describe and relate to each other the geometric properties of the elements of stator 1, such as laminated stator core 2, rod conductor 6, interconnection planes 5, etc.

[0046] FIG. 4 shows a perspective view of a stator 1 similar to FIG. 3 with a cooling channel according to the present invention and with fluid flows drawn in (see arrows that are not filled) and pressure forces (see filled arrows). Stator 1 is configured with a cooling housing 20 and cooling ribs or a winding 44, respectively. Cover unit 21 with inner ring 22 can be seen on the upper side and, in combination with outer ring 28 of cooling housing 20, form annular gap inflow 25 and annular gap outflow 26.

[0047] FIG. 5 shows a longitudinal sectional view through an upper part of a stator 1 similar to FIGS. 3 and 4, in particular its winding head with a cooling channel according to the invention, where fluid flows are shown on the right-hand side of the figure. Stator 1 is equipped with a cooling housing 20 and a fluid housing 48. Fluid housing 48 has a cylindrical outer wall 50 and an annular cover 51. Outer wall 50 abuts directly against cooling housing 20. Cover 51 is attached to outer wall 50 and comprises one or more openings 27 for a fluid inflow and an opening for a fluid outflow. Cover 51 can also be configured as a bearing shield for supporting a rotor or a rotor bearing. Fluid inflow 27 is directed towards cover unit 21 and presses it by way of a fluid flow downwardly or onto laminated stator core 2. Cover unit 21 is formed to be movable relative to cover 51 in the axial direction. Disposed between cover unit 21 and cover 51 is a sealing device 55, in the present example an O-ring, which seals annular gap 17 against the interior of the stator or fluid outlet 26, respectively. Laminated stator core 2 with rod conductors 6 and 6a, as well as the winding head with various interconnection webs 9, insulation rings 32 of cover unit 21 with inner ring 22, and annular gaps formed as a result for inflow and outflow 25 and 26 are clearly visible in the enlarged cross-section along the longitudinal axis or axis of rotation 23 of stator 1. Webs 9 and conductors 6, 6a are attached, in particular welded, to one another at contact points 33. First annular chamber 16 and second annular chamber 17 arranged thereabove are separated from one another by cover unit 21 and connected to one another by inflow 25.

[0048] In particular the plurality of stacked insulation rings 32 can be pressed against one another and sealed against one another by way of pressurized cover unit 21 in a simple manner at their contact points or surfaces.

LIST OF REFERENCE CHARACTERS

[0049] 1 stator [0050] 2 laminated stator core [0051] 3 winding head side A [0052] 4 winding head side B [0053] 5 interconnection plane [0054] 6 rod conductor [0055] 6a rod conductor [0056] 7 interconnection plane with phase connection [0057] 8 phase connection [0058] 9 interconnection webs/end connectors [0059] 10 electric machine [0060] 11 cooling channel for winding head side A [0061] 12 cooling channel for winding head side B [0062] 13 rotor [0063] 14 rotor shaft [0064] 15 laminated rotor core [0065] 16 first annular chamber of the cooling channel [0066] 17 second annular chamber of the cooling channel [0067] 20 cooling housing/sleeve [0068] 21 cover [0069] 22 inner ring [0070] 23 axis of rotation [0071] 25 annular gap inflow [0072] 26 annular gap outflow [0073] 27 inflow opening of the fluid housing [0074] 28 outer ring [0075] 29 slots [0076] 31 partition wall, vertical [0077] 32 partition wall, horizontal or insulating ring/washer [0078] 33 contact/welding of rod conductors to interconnection web [0079] 40 group of interconnection web [0080] 44 turns/cooling ribs [0081] 45 sealing mat [0082] 47 adapter piece/ring [0083] 48 fluid housing [0084] 50 outer wall of the fluid housing [0085] 51 cover of the fluid housing [0086] 55 sealant