Covering device with double steel plates for rotor

Abstract

The invention relates to a covering device (5) for a rotor (1) of a separately excited machine for covering a winding head of a rotor winding of the rotor, comprising: a first covering element (6) having a metal, formed, deep-drawn first covering sheet (7) for covering the winding head, the first cover plate has a plurality of plate curvatures (8) arranged distributed in the circumferential direction, which form a shell-like recess for partially receiving the winding head on the lower side of the first cover plate facing the winding head and form a projection (10) on the upper side (9) of the first cover plate,-a second cover element (12), the invention relates to a cover for a motor vehicle, comprising a metal, rotationally symmetrical second cover sheet (13), by means of which a disc-shaped cover is formed, said cover being arranged so as to overlap the upper side of the first cover sheet in the axial direction, said cover sheets being mechanically connected and forming a cavity between the upper side of the first cover sheet and the second cover sheet.

Description

Technical Field

[0001] This invention relates to a covering device for the rotor of a separately excited motor, which covers the rotor windings of the rotor arranged at the end of the rotor body. The invention also relates to a rotor. Background Technology

[0002] In the present context, there is interest in separately excited or electrically excited motors used in electrified motor vehicles, such as electric or hybrid vehicles. Such machines typically have a fixed stator and a rotor supported in a manner rotatable about the stator. The rotor has energized rotor windings held by a rotor body, such as a rotor lamination assembly. In a salient-pole configuration, the winding conductors of the rotor windings are wound around salient poles and thus locally arranged in axial slots within the rotor body. The winding sections of the rotor windings, guided at the end sides of the rotor body, form axially extending winding heads at the end sides. Furthermore, the rotor typically has a covering device that axially covers the rotor body to cover and enclose the winding heads. This covering device can also be used to cool the winding heads. To optimize cooling efficiency, the distance between the winding heads and the covering device should be as small as possible to reduce thermal resistance.

[0003] To address this, DE102022111413A1 proposes equipping the rotor with at least one end-side member, which is arranged on the rotor body at the end, axially and outwardly covering the rotor windings, and whose geometry corresponds to the outer contour of the rotor windings on its side facing the rotor base. The end-side member is here constructed as a die casting, particularly an aluminum die casting, for stability reasons. However, such a die casting is costly and expensive to manufacture. Summary of the Invention

[0004] The objective of this invention is to provide a cost-effective, stable, and highly efficient cooling shielding device for the rotor of a separately excited motor.

[0005] According to the present invention, the task is accomplished by a covering device having the features according to the respective independent claims and a rotor. Advantageous embodiments of the invention are the technical solutions described in the dependent claims, the specification, and the drawings.

[0006] The covering device for a rotor of a separately excited motor according to the present invention is used to cover the winding head of the rotor windings arranged at the end side of the rotor body. The covering device includes a first covering element having a metal, shaped, deep-drawn first covering plate for covering the winding head, the first covering plate having a plurality of plate arches arranged circumferentially. These plate arches form shell-shaped recesses on the underside of the covering plate facing the winding head for at least partially receiving the winding head and form bulges on the upper side of the first covering plate. Furthermore, the covering device includes a second covering element having a metal, rotationally symmetrical second covering plate, through which a disk-shaped cover is formed, axially overlapping the upper side of the first covering plate. The covering plates are mechanically connected and form a cavity between the upper side of the first covering plate and the second covering plate.

[0007] The rotor for a separately excited motor according to the invention comprises: a rotor body; a rotor winding held by the rotor body and forming a winding head at opposite end sides of the rotor body; and at least one covering device according to the invention, which is arranged overlapping one end side of the rotor body to cover the associated winding head and is mechanically connected to the rotor body. In particular, the rotor body includes two covering devices according to the invention, which are arranged axially on both sides of the rotor body. The rotor body is particularly constructed as a lamination assembly of axially stacked sheet metal. The rotor body is particularly manufactured in a salient pole configuration and has an annular rotor yoke, with the rotor shaft passing through the rotor yoke. The rotor shaft is connected to the rotor body in a manner that prevents relative rotation. Salient poles are distributed on the rotor yoke in the circumferential direction, each having a pole tooth extending radially from the rotor yoke and particularly parallel to its sides, and a pole shoe radially adjacent to the pole tooth and tangentially or laterally protruding on the pole tooth. A slot is formed between two adjacent pole teeth, extending axially through the rotor body between the two end sides. A pole gap is formed between two adjacent pole shoes, the tangential width of which is smaller than the tangential width of the corresponding slot, and the pole gap forms an entry opening to the corresponding slot.

[0008] The slot contains axial winding sections of the rotor winding. At the end sides, winding sections of the rotor winding are arranged to form winding heads. The rotor windings particularly have wire-shaped winding conductors wound around pole teeth in multiple layers and turns. Since the winding heads are subjected to high mechanical loads due to rotation during motor operation, a corresponding star disk is specifically arranged abuttingly on the corresponding end side and thus between the rotor body and the corresponding winding head to support the winding head. Furthermore, the star disk serves as electrical insulation between the winding conductors and the rotor body.

[0009] Furthermore, the winding head is covered or encapsulated by a covering device. Each covering device is multi-piece and has two covering elements arranged axially overlapping each other. Each covering element has a covering plate, preferably made of steel. Additionally, each covering element may have a guide passage for a rotor shaft that is non-rotatably connected to the rotor body, the guide passage being configured as a through opening in the respective covering plate. The through opening may be configured as a hole centrally located in the respective covering plate, the hole being formed, for example, by punching from a steel plate.

[0010] The first cover plate is arranged adjacent to the winding head. Here, the cover plate has a profile formed by cost-effective deep drawing, the profile following the surface orientation of the end side of the rotor body equipped with the winding head. For this purpose, an arched portion is introduced during the deep drawing of the first cover plate, the arched portion forming a shell-like recess or depression on its lower side. The recess is a cavity that opens at least towards the end side on the lower side, wherein each recess receives a winding head. Through the recess, the distance between the surface of the winding head and the lower side of the cover plate is substantially constant, and can be particularly small to reduce the thermal resistance between the winding head and the cover device. The arched portion forms a bulge or protrusion on the upper side of the first cover plate, opposite to the lower side in the axial direction, due to the bulge or protrusion, the surface of the first cover plate is not rotationally symmetrical. Therefore, the upper side of the first cover plate is not a rotating surface.

[0011] To prevent this rotationally asymmetrical surface from causing eddy currents on the end face of the rotating rotor during motor operation (which reduces motor efficiency), the upper side of the first cover plate is covered by a second cover element to form a cavity. The second cover plate is constructed as a rotationally symmetrical, plate-shaped cover. For example, the first cover plate may have an axially extending flange region that protrudes axially relative to the raised portion, and the cover abuts against the circular edge of the flange region to close the cavity. Thus, the resulting cavity is axially bounded by the upper side of the first cover plate and therefore the lower side of the cover, and radially outwardly bounded by the flange region of the first cover plate. Therefore, the covering device has a double-walled closed plate.

[0012] The mechanical connection of the cover elements results in a cover device with exceptionally high mechanical stability, comparable to that of die-cast components. For example, the cover elements can have connection regions for mechanically connecting the cover elements, these regions being constructed as screw holes arranged aligned with each other in the cover plate. Screws can be guided through these screw holes, via which the cover plate is mechanically connected. The second cover plate can also be deep-drawn. Therefore, for example, a circumferential groove or annular groove can be constructed in the upper side of the cover, and the screw holes can be located in the groove or annular groove, such that the screw heads are recessed when the cover element is screwed on and therefore do not protrude from the cover. Furthermore, the cover device can be screwed onto a corresponding star-shaped disk for mechanical connection with the rotor body.

[0013] Particularly preferably, the covering device has an annular outer cover element that extends from the edge of the cover toward the end side and radially surrounds the first covering element. Therefore, in the arrangement of the outer cover elements, the first covering plate forms an inner covering plate or inner covering plate, and the second covering plate forms an outer covering plate or outer covering plate. The outer cover element can, for example, be constructed as a cylindrical stahl bandage. For example, the outer cover element can close a recess that is also radially open. Furthermore, the outer cover element can radially surround and stabilize a corresponding star-shaped disk by means that the axially extending, radially outwardly arranged top of the star-shaped disk is supported on the inner surface of the outer cover element.

[0014] Advantageously, the cavity is configured as a cooling channel for guiding a cooling medium designed to cool the winding head. The cooling medium can be guided close to the winding head via a first cover plate arranged at a small distance from it, thus absorbing and discharging residual heat from the winding head. The cooling medium can be, for example, configured as a cooling liquid in the form of oil. For example, the cover device can have an inlet region and an outlet region, the inlet region being aligned with a cooling medium discharge opening in the rotor shaft of the rotor that guides the cooling medium, and the outlet region for radially discharging the cooling medium guided in the cavity. The outlet opening can be, for example, configured as a slit in the cover. For this purpose, the rotor shaft can be configured as a hollow shaft for guiding the cooling medium and has a cooling medium discharge opening in its wall for discharging the cooling medium into the cavity of the at least one cover device. Here, the cooling medium can be transported solely by centrifugal force from the radially inner inlet region to the radially outer outlet region by the rotation of the rotor. By discharging the cooling medium radially, the cooling medium can be thrown onto the stator winding heads surrounding the rotor due to rotation and thus additionally serve to cool the stator winding heads in an advantageous manner.

[0015] Furthermore, the first cover element may have a collection area for collecting the cooling medium, the collection area being constructed as a groove (Sicken) in the upper side of the first cover plate. The groove collects the cooling medium in an area of ​​the winding head at the point of potential overheating before it is discharged through the outlet opening due to centrifugal force. The grooves may be arranged circumferentially on the upper side. For example, one groove may be arranged between each of two adjacent protrusions. This ensures particularly reliable cooling of the rotor winding head.

[0016] The embodiments and advantages proposed regarding the covering device according to the invention are correspondingly applicable to the rotor according to the invention.

[0017] Other features of the invention are derived from the claims, the drawings, and the description of the drawings. The features and combinations thereof mentioned in the foregoing description, and those mentioned in the following description of the drawings and / or shown separately in the drawings, can be used not only in the corresponding combinations, but also in other combinations or alone. Attached Figure Description

[0018] The invention will now be explained in more detail with reference to preferred embodiments and the accompanying drawings. In the drawings:

[0019] Figure 1 A schematic perspective view of a rotor with a covering device is shown; and

[0020] Figure 2 A schematic perspective view showing the rotor and the first covering element of the covering device. Detailed Implementation

[0021] In the accompanying drawings, identical and functionally identical elements are given the same reference numerals.

[0022] Figure 1 A rotor 1 for a separately excited motor is shown, which can be used, for example, as a drive machine for an electrified motor vehicle. The rotor 1 is configured as an inner rotor and can be rotatably supported within a hollow cylindrical stator of the motor. The rotor 1 has a rotor body 2. The rotor body 2 has slots for receiving rotor windings of the rotor 1, which are not visible here, wherein the slots are closed by slot closing elements 3 or cover slides. A rotor shaft 4 is guided through the rotor body 2, which is configured as a hollow shaft and designed to guide cooling medium axially through the rotor body 2. Furthermore, the rotor 1 has two covering devices 5, which are arranged overlapping the rotor body 2 at their ends and designed to surround the winding heads of the rotor windings.

[0023] As in Figure 2As shown, each covering device 5 has a first covering element 6, which has a first covering plate 7 formed by three-dimensional deep drawing. The covering plate 7 is made of steel plate and has a plate arch 8 formed by deep drawing. The plate arch 8 forms a recess for receiving the winding head on the lower side of the first covering plate 7, which is not visible here. On the upper side 9 of the first covering plate 7, the plate arch 8 forms a ridge 10. In addition, a groove 11 is formed here on the upper side 9 between the two ridges 10. Here, a flange region 21 with the annular edge 22 of the first covering plate 7 is constructed in such a way that it protrudes axially at the ridge 10.

[0024] The second cover element 12 is arranged overlapping the upper side 9 of the first cover plate 7. The second cover element has a second cover plate 13, which is also made of steel plate and forms a rotationally symmetrical, plate-shaped cover. The cover 13 can be placed on the edge 22, for example. Here, an outer cover element 14 made of steel hoops radially surrounds the assembly head and extends axially from the end side of the rotor body 2 to the second cover plate 13. By constructing the cover plates 7 and 13 as steel plates, the necessary strength is met with low material requirements and is significantly more advantageous in manufacturing. Furthermore, the expected cooling performance is equivalent to that of a conventional die-cast aluminum cover.

[0025] The cover elements 6 and 12 are mechanically connected by screws 15, which additionally fix the cover device 5 to the rotor body 2. For this purpose, the cover elements 6 and 12 have fixing areas formed by screw holes arranged aligned with each other in the respective cover plates 7 and 13. The upper side 16 of the cover 13 has grooves 17 or slots, for example formed by deep drawing, in which screw holes for countersunk placement of the screws 15 are arranged. Furthermore, the two cover plates 7 and 13 have filling openings 18 arranged aligned with each other for casting material used to pour the rotor 1. Additionally, the cover device 5 has a guide passage 19 for the rotor shaft 4, formed by through openings 20 arranged aligned with each other in the cover plates 7 and 13.

[0026] The mechanically connected shielding elements 6 and 12 constitute a shielding device 5 with substantially rotationally symmetrical surfaces that reduce eddy currents. Furthermore, the shielding elements 6 and 12 enclose cavities that form cooling channels for the cooling medium used to cool the winding heads. Therefore, the cooling medium supplied by the rotor shaft 4, which is constructed as a hollow shaft, can be collected between the shielding plates 7 and 13 to fully utilize the cooling potential of the shielding device 5. Here, the cooling medium is not carried away from the end side by the ambient air in the motor chamber when the rotor 1 rotates and can be evenly distributed on the upper side 9 of the first shielding plate 7, thus better drawing heat away from the first shielding plate 7. Furthermore, the cooling medium can be collected through the grooves 11 in the first shielding plate 7 to further maximize cooling power before the cooling medium is thrown out through, for example, an outlet arranged in the second shielding plate 13.

Claims

1. Covering device (5) for a rotor (1) of a separately excited electrical machine for covering a winding head of a rotor winding of the rotor (1) arranged at an end side of a rotor body (2) of the rotor (1), the covering device having: - a first covering element (6) having a metallic, profiled, deep-drawn first covering sheet (7) for covering the winding head, the first covering sheet having a plurality of sheet arches (8) arranged distributed in a circumferential direction, wherein - a first covering element (6) having a metallic, rotationally symmetrical first covering sheet (7) which constitutes a disc-shaped cover arranged axially overlapping an underside of the winding head, - a second covering element (12) having a metallic, rotationally symmetrical second covering sheet (13) which constitutes a disc-shaped cover arranged axially overlapping an upper side (9) of the first covering sheet (7), - wherein the covering sheets (7, 13) are mechanically connected and form a cavity between the upper side (9) of the first covering sheet (7) and the second covering sheet (13).

2. Covering device (5) according to claim 1, characterized in that The covering sheets (7, 13) are made of a steel sheet.

3. Covering device (5) according to claim 1 or 2, characterized in that The covering device (5) has an annular housing element (14) which is configured extending in the direction of the respective end side from an edge of the cover (13) and which radially surrounds the first covering element (6).

4. Covering device (5) according to any one of the preceding claims, characterized in that The first covering sheet (7) has a flange region (21) extending axially which projects axially with respect to the elevation (10), the cover (13) resting on the flange region to close the cavity.

5. Covering device (5) according to any one of the preceding claims, characterized in that The cavity is configured as a cooling channel for a cooling medium which is configured for cooling the winding head.

6. Covering device (5) according to claim 5, characterized in that The covering device (5) has an inlet region which is arranged in alignment with a cooling medium discharge opening in a rotor shaft (4) of the rotor (1) for guiding a cooling medium and an outlet region for radially discharging the cooling medium guided in the cavity.

7. Covering device (5) according to claim 5 or 6, characterized in that The first covering element (6) has a collection region for collecting a cooling medium which is configured as a recess (11) in the upper side (9) of the first covering sheet (7).

8. Covering device (5) according to any one of the preceding claims, characterized in that The covering elements have a connection region for mechanically connecting the covering elements which is configured as screw holes arranged in alignment with one another in the covering sheets.

9. Rotor (1) of a separately excited electrical machine, the rotor having: - a rotor body (2), - a rotor winding held by the rotor body (2) and constituting a winding head at opposite end sides of the rotor body (2); and - at least one covering device (5) according to any one of the preceding claims arranged overlapping one of the end sides of the rotor body (2) to cover the associated winding head and mechanically connected with the rotor body (2).

10. The rotor (1) according to claim 8, characterized in that The rotor (1) has a rotor shaft (4) which runs through the rotor body (2) and the at least one cover device (5) in the axial direction and is connected to the rotor body (2) in a rotationally fixed manner, the rotor shaft (4) being configured as a hollow shaft for conducting a cooling medium and having a discharge opening for discharging the cooling medium into a cavity of the at least one cover device (5). The rotor (1) has a rotor shaft (4) which runs through the rotor body (2) and the at least one cover device (5) in the axial direction and is connected to the rotor body (2) in a rotationally fixed manner, the rotor shaft (4) being configured as a hollow shaft for conducting a cooling medium and having a discharge opening for discharging the cooling medium into a cavity of the at least one cover device (5). The rotor (1) has a rotor shaft (4) which runs through the rotor body (2) and the at least one cover device (5) in the axial direction and is connected to the rotor body (2) in a rotationally fixed manner, the rotor shaft (4) being configured as a hollow shaft for conducting a cooling

Images