ROTOR PARA MÁQUINA ELÉTRICA

Abstract

rotor for electric machine. The invention relates to a rotor for an electric machine, having a laminated core (1) with slots in which lower bars (3) and upper bars (4) are arranged, which extend in the axial direction (5) beyond the laminated core (1) to form an extended winding head, wherein a lower bar (3) of one slot is connected to an upper bar (4) of another slot in the winding head and the lower bars (3) and the upper bars (4) cross axially outside the laminated core (1) in a top view at the crossing points (8) and gaps (9) remain between the crossing points (8), wherein a support device is provided having a retaining body (10) arranged radially within the winding head and at least one U-shaped fastener (11) with two rods (12) and a connecting piece (13),wherein the U-shaped fastener (11) is connected both to the retaining body (10) and to an upper bar (4) to radially support the upper bar (4) by means of the retaining body (10). In order to ensure robust stabilization of the winding head even when there is only a small distance between the gaps (9), the invention provides that the rods (12) project through two gaps (9) which are connected to different upper bars (4).

Description

1 / 24 Descriptive Report of the Invention Patent for ROTOR FOR ELECTRIC MACHINE.

[001] The invention relates to a rotor for an electric machine, having a laminated core with slots in which lower and upper bars are arranged, which extend in the axial direction beyond the laminated core to form a winding head, wherein, respectively, a lower bar of one slot is connected to an upper bar of another slot in the winding head and the lower and upper bars cross axially outside the laminated core in a plan view at the crossing points and gaps remain between the crossing points, wherein a support device is provided having a retaining body arranged radially within the winding head and at least one U-shaped clamp with two rods and a connecting piece, the U-shaped clamp being connected both to the retaining body and to an upper bar to radially support the upper rod by means of the retaining body.

[002] Rotors of the type mentioned are known in the state of the art, which are used, for example, in asynchronous machines in reversible hydroelectric plants, asynchronous machines are used both as a motor and as a generator.

[003] During operation, centrifugal forces act on the rotor and, in particular, on the upper and lower bars due to the rotor's rotation around a rotor axis. The upper and lower bars are generally supported against these centrifugal forces in the laminated core area by slot wedges. Outside the laminated core, in the winding head, this is not possible, which is why US Patent No. 5,606,212 A, in particular, discloses a support device having a U-shaped clamp, which has a U-shaped clamp that is mounted by a Petition 870230061400, dated 07 / 13 / 2023, page 8 / 59 2 / 24 side radially inside the end winding on a rotating ring disc and on the other side encompasses an upper bar and a lower bar to support this upper bar and the lower bar against the centrifugal forces acting during operation. The rods of this U-shaped fastener are guided through two adjacent openings in the laminated rotor core, so that the U-shaped fastener projects from an interior of the rotor winding head to a radial exterior of the rotor winding head.

[004] Depending on the specific requirements of an electric machine, the number of pole pairs, the diameter and length of the rotor winding head, and the dimensions of the upper and lower bars and the angle at which the upper bars are in the final winding area to the lower bars may vary. It has been demonstrated that, with the design proposed in US Patent No. 5,606,212, unacceptably high mechanical loads act on the retaining body, the U-shaped retainer, and / or the lower bars in some rotors. Particularly in the case of rotors in which the gaps in the winding head are close together, the known configuration of Patent No. 5,606,212 leads to particularly narrow and therefore highly stressed ring discs, in which deviations caused by manufacturing tolerances may cause permissible mechanical limit values ​​to be exceeded.

[005] This is where the invention comes in. The objective of the invention is to specify a rotor of the type mentioned in the introduction, in which the winding head can be robustly stabilized, even if there are gaps in the winding head particularly close to each other.

[006] This objective is achieved by a rotor of the type mentioned in which the rods project through two openings that are contiguous to different upper rods. Petition 870230061400, dated 07 / 13 / 2023, p. 9 / 59 3 / 24

[007] The inventors recognized that, with an appropriate design, a retaining body, which is usually designed as a circumferential ring, can be used with a larger cross-section, thereby reducing mechanical loads. Thus, in prior art devices, the U-shaped fastener rods always project between directly adjacent gaps, which thus constrain the same upper bar, so that a U-shaped fastener always encloses only one upper bar.

[008] In the rotor design according to the invention, the rods thus protrude through two gaps, which are usually separated from each other by at least one more gap, and the U-shaped holder thus normally encompasses at least two upper rods. This achieves a greater distance between the rods, which generally enclose the retaining body within the winding head and are connected to it in a manner fitted in the radial direction.

[009] The U-shaped fastener rods generally extend exclusively in the radial direction. The connecting piece, which preferably connects the U-shaped fastener radially to the outside of the rotor winding head, generally extends approximately parallel to an axial direction or parallel to the rotor axis. Correspondingly, an axial extension of the retaining body or a retaining ring generally corresponds essentially to an axial extension of the connecting piece.

[0010] The terms axial direction, radial direction and circumferential direction are to be understood here in the sense of a cylindrical coordinate system, the axial direction coinciding with an axis of the rotor, around which the rotor is rotatably arranged in a stator during normal operation, or being parallel to this axis of the rotor.

[0011] Crossing points are here designated as points where an upper bar and a lower bar intersect in the region of Petition 870230061400, dated 07 / 13 / 2023, page 10 / 59 4 / 24 winding head in a plan view or when viewed along the radial direction, the upper bar being arranged at a greater radial distance from the rotor axis than the lower bar. Gaps are positions in which neither a lower bar nor an upper bar is arranged when viewed in the appropriate direction, so that unimpeded passage of a U-shaped fastener from an interior of the rotor winding head to an exterior of the rotor winding head is possible along the radial direction.

[0012] With a corresponding design, the connecting piece generally encompasses at least two crossing points, so that at least two upper bars and two lower bars are kinematically coupled or connected in positive union and / or frictional union to the support device in the radial direction by a U-shaped fastener.

[0013] By means of a correspondingly enlarged cross-section of the retaining body, the design according to the invention can also be used in rotors in which the gaps in the rotor winding head are very close to each other, for example, because the upper and lower bars are very narrow and / or the upper and lower bars intersect at an angle of almost 90°, especially since a length of the connecting piece and therefore an axial extension of the retaining body is not defined by a distance between two adjacent gaps, but the axial extension of the retaining body can also be a multiple of a distance between two adjacent gaps.

[0014] In addition, the surface pressure of the upper and lower bars is reduced.

[0015] Furthermore, a corresponding rotor can be produced with a reduced number of U-shaped fasteners, especially since a U-shaped fastener with a design Petition 870230061400, dated 07 / 13 / 2023, p. 11 / 59 The 5 / 24 corresponding system can encompass and stabilize multiple upper and lower bars.

[0016] The retaining body preferably has an axial extension that corresponds to a multiple, in particular twice, of the distance between two gaps in the rotor winding head, which gaps are located along a circumferential direction in the same circumferential position, i.e., they are spaced only axially from each other. With correspondingly large dimensions of the retaining body, the deviations caused by manufacturing tolerances also have less effect on the mechanical stresses in the retaining body, so it is easy to manufacture.

[0017] In principle, the U-shaped fastener can be installed in any desired manner to connect the retaining body to the upper bar, so that the winding head is supported in the corresponding area by the U-shaped fastener on the retaining body and thus radially stabilized. The connecting piece can therefore, in principle, also be arranged radially inside the rotor winding head and connected to the retaining body.

[0018] However, it is preferably provided that the connecting piece is arranged radially outside the upper bars and is connected to at least two upper bars. As a result, a simple yet robust structure is obtained in an area between the rotor winding head and the stator winding head.

[0019] Naturally, the connecting piece can also encompass more than two top bars, for example, three or four top bars.

[0020] Furthermore, the U-shaped fastener can, in principle, be connected to the retaining body in any way, for example, Petition 870230061400, dated 07 / 13 / 2023, page 12 / 59 6 / 24 screwed into the retaining body or similar.

[0021] However, it is preferably provided that the retaining body is ring-shaped and the rods project to an inner diameter of the retaining body, in particular to reduce pressure peaks. A radial force transmitted through the U-shaped fastener to an interior of the winding head is then preferably applied to the retaining body through the inner diameter of the retaining body or an inner cylindrical surface.

[0022] A locking element is preferably provided that is removablely connected to the rods. The U-shaped fastener can be attached to the retaining body and the winding head by means of this locking element.

[0023] The retaining body is generally connected to the U-shaped fastener by means of the locking element. The U-shaped fastener preferably rests radially inside the retaining body, so that the centrifugal forces transmitted from the connecting piece to the rods, which act on the rotor winding head and are absorbed by the U-shaped fastener, are transmitted through the locking element to an inner diameter of the retaining body, preferably ring-shaped, generally via surface contact, in order to avoid pressure peaks.

[0024] Thus, a radial force is normally transmitted from the upper bars to the connecting piece, from the connecting piece to the rods, from the rods to the locking element and, finally, from the locking element to the retaining body, usually on an inner diameter of the retaining body.

[0025] It has been proven that the locking element has radial through holes through which the rods project, in which fastening elements, in particular nuts, downstream of the rods and the locking element are provided, which fasten the locking element to the rods. Petition 870230061400, dated 07 / 13 / 2023, page 13 / 59 7 / 24 This ensures easy assembly. A preset tightening torque for the nuts can be used to introduce a defined preload on the rods, so that the rotor winding head can be pressed against the retaining body by a preset force.

[0026] Especially to equalize the effects of settling and / or creep in the area of ​​the U-shaped fastener, it is preferable to provide that spring elements, in particular disc springs or helical disc springs, are arranged between the fastening elements and the locking element, which are preferably pre-tensioned with a predefined pre-tensioning force. The settling effects that occur during operation over a long period of time can be easily compensated for in this way, so that a predefined pre-tension can also be maintained for a long period of time. Manual tightening of the nuts after a break-in phase is no longer necessary. At the same time, undesirably high pre-tensions on the rods are avoided during the break-in phase.

[0027] Spring elements can be formed by a series and / or parallel combination of individual springs, in particular individual cup springs.

[0028] In addition, spring elements can also be designed as helical springs made of flat wire that are screwed together, so-called helical disc springs. Compared to a stack of disc springs, a longer service life is obtained. Furthermore, assembly is simplified compared to a stack of disc springs, especially since the use of a helical disc spring with a corresponding length can achieve a characteristic equivalent to several disc springs or a stack of disc springs, so that the number of components is reduced. Petition 870230061400, dated 07 / 13 / 2023, p. 14 / 59 8 / 24

[0029] Normally, spring elements are brought to a predefined pretension during assembly in order to compensate for the effects of settling by correspondingly relaxing the spring elements during operation. A defined pretension can be achieved, for example, by a sleeve or a steel sleeve, which is arranged parallel to a stack of disc springs or on a helical plate spring, in particular it is arranged on the stack of disc springs or on the helical plate spring, and serves as a stop for a nut, with which the disc springs or the helical disc spring can be tensioned. The nut can thus only be tightened to a position defined by a position of the stop or a length of the sleeve, so that a maximum deformation and thus a pretension of the spring element can be clearly defined.

[0030] Thus, a defined inclination can be achieved mostly without the use of a hydraulic clamping cylinder, for which there is often not enough space available.

[0031] Particularly preferentially, the pre-tensioning is selected in such a way that the rotor winding head, i.e., the upper and lower bars, only lift from the retaining body above a nominal speed. Thus, even with a comparatively large number of start-stop cycles, a low tension amplitude is achieved in an area of ​​the U-shaped fastener threads, through which the nuts are connected to the U-shaped fastener. In case of failure, the machine may go beyond the nominal speed to the loss of load speed or runaway speed. In such cases, the stop acts as an overload protection for the spring.

[0032] Furthermore, in the case of particularly high speeds with the stop, unacceptably large deformations of the winding head can be avoided. Petition 870230061400, dated 07 / 13 / 2023, page 15 / 59 9 / 24

[0033] The rods of the U-shaped fastener are generally under high mechanical stress, especially because the centrifugal forces of the rotor winding head act upon them. Therefore, it has proven useful for the rods to have wires, which are preferably formed by wire lamination. As a result, the fastening elements, which can be designed in particular as nuts, can be robustly arranged in the U-shaped fastener.

[0034] It has been proven that the U-shaped fastener is made of an austenitic material, in particular an austenitic steel. On the one hand, this is advantageous due to the prevailing magnetic field in the rotor winding head. On the other hand, an austenitic material has also proven to be very advantageous for a corresponding application with regard to mechanical properties.

[0035] In order to guarantee robust support of the rotor winding head even at high speeds, it is preferable to provide that the U-shaped clamp be made of a cold-worked metal, in particular a cold-drawn steel.

[0036] It is advantageous to provide that the retaining body is made of a ferritic material, in particular a ferritic steel, or is formed from such a material. As a result, the mechanical requirements can be met in a particularly reliable manner.

[0037] It is particularly preferred for this purpose that the retaining body be a fine-grained steel, in particular S460, or a tempered fine-grained steel, in particular S550Q.

[0038] To ensure particularly low magnetic losses in the winding head area, it is preferred that the retaining body have a ferritic inner part and a non-magnetic outer part, consisting in particular of aluminum, a fiber composite material or a hard fabric, for example epoxy resin hard glass fabric (EPGC). The retaining body may have, for example, a ring Petition 870230061400, dated 07 / 13 / 2023, page 16 / 59 10 / 24 inner ferritic ring and a non-magnetic outer ring, which may consist, for example, of aluminum, a fiber composite material or a hard fabric, for example EPGC. The inner ring and the outer ring may also be movable relative to each other. In this case, the outer ring may be rigidly coupled to the lower bars in the axial direction and the inner ring may be rigidly coupled to the laminated core in the axial direction. It may also be provided that a contact surface between the inner ring and the outer ring is made of a material with a particularly low coefficient of friction to minimize wear.

[0039] A particularly robust design is achieved when the retaining body is rigidly connected to the laminated core in the axial direction. For this purpose, the retaining body can be connected, for example, by means of screws to a pressure plate, which in turn is rigidly connected to the laminated core.

[0040] To prevent centrifugal forces acting on the winding head from causing additional mechanical stresses in the laminated core, it is preferred to provide that the retaining body be connected to the laminated core so that it can move in the radial direction, in particular by means of a radial guide. This ensures that centrifugal forces in the winding head area lead only to deformation of the winding head and the retaining body, but not to radial deformation of the laminated core, especially since the retaining body is decoupled from the laminated core in the radial direction. The guide may have, for example, grooves in the retaining body or in the pressure plate and corresponding guide pins in the pressure plate or in the retaining body.

[0041] It is preferably provided that a component rigidly connected to the laminated core of the rotor, in particular a pressure plate, has first guide means running in the radial direction, in particular radial grooves, and the retaining body has second Petition 870230061400, dated 07 / 13 / 2023, p. 17 / 59 11 / 24 corresponding guide means, in particular guide pins, which engage with the first guide means, so that the retaining body can be moved in the radial direction by the cooperating guide means and is rigidly connected to the laminated core in the circumferential direction.

[0042] Depending on the dimensions of the rotor winding head, a single retaining body, usually circumferential, may in principle be sufficient, which is generally coupled to the rotor winding head in the radial direction by means of U-shaped fasteners arranged distributed along a circumference. Particularly in the case of very large winding heads, it is preferable to provide several retaining bodies, in particular three, in the axial direction, which are kinematically coupled in the circumferential direction by means of radial guides and can be moved relative to each other in the radial direction, wherein the radial guide means are preferably formed by radial slots and corresponding guide pins, which fit into the radial slots.Thus, the individual retaining bodies can be supported in the axial and circumferential directions against each other or against the laminated rotor core, and yet can be moved relative to each other in the radial direction. This is particularly advantageous because the rotor end winding can have a greater radial deformation at an axial end than in the area near a laminated core.

[0043] For a robust axial connection of the retaining bodies to the rotor core, it has proven useful for the retaining bodies to be axially connected to the pressure plate by bolts, wherein the bolts extend continuously from an axially external retaining body to the pressure plate and are, in particular, under a defined pre-tension. However, to ensure radial mobility between the individual retaining bodies, the bolts can be guided, for example, through holes in the retaining bodies that are larger than Petition 870230061400, dated 07 / 13 / 2023, p. 18 / 59 12 / 24 screws.

[0044] Electric machines with rotor cores are frequently manufactured in such a way that the rotor core is shrunk into a rotor body, wherein openings extending in the axial direction may be provided in the rotor body for ventilation of the laminated rotor core from within. The shrinking of the laminated rotor core thus leads to a deformation of the laminated rotor core, which corresponds to the openings or arms into which the laminated rotor core is shrunk.

[0045] To ensure particularly reliable orientation of the retaining body in the radial direction, even when the rotor is formed with a shrink fit, and to prevent movement of the retaining body relative to the laminated rotor core in the circumferential direction, a design has proven advantageous, in which the rotor has a rotor body with arms arranged along a circumferential direction and openings arranged between the arms through which cooling air can be supplied to the laminated rotor core, in which the laminated core is shrunk into the rotor body, in which the first guide means, which extend radially, are arranged along a circumferential direction in positions corresponding to the positions of the arms in the area of ​​a pressure plate and / or with positions halfway between the corresponding arms in the area of ​​the pressure plate.Thus, the pressure plate or the rotor's laminated core is only radially deformed in these positions when it is retracted, and there is no regional torsion in these areas. As a result, the guides would become curved, and their proper functioning would no longer be guaranteed under all operating conditions. These positions in the middle of the arms and in the middle between the arms can therefore also be called torsion-free areas.

[0046] The bars are generally oriented approximately parallel to the axial direction. In addition, the fastener rods are shaped Petition 870230061400, dated 07 / 13 / 2023, page 19 / 59 13 / 24 of Us are generally oriented approximately in the radial direction. As a result, the members are essentially subjected only to tensile stresses and, in particular, bending and torsional stress in the members is essentially avoided.

[0047] Depending on the size of the winding head, it may be foreseen that a plurality of U-shaped fasteners will be distributed along a circumferential direction. In the circumferential direction, the U-shaped fasteners are generally positioned in a regularly distributed manner along the entire circumference of the rotor winding head.

[0048] Depending on the size of the winding head, it may also be advantageous if several U-shaped clamps are provided in the axial direction. The U-shaped clamps are therefore preferably distributed over the rotor winding head, both in the circumferential and axial directions, in order to stabilize the rotor winding head uniformly in various positions by means of the internal retaining body.

[0049] It is generally provided that the retaining body encloses the rotor shaft and is in particular in the form of a plate, preferably in the form of a ring, particularly preferably as an annular disc. The centrifugal forces acting on the retaining body can then be particularly well absorbed, resulting in good stabilization of the winding head.

[0050] As mentioned, it may be advantageous if the U-shaped retainer rods are under pre-tensioning, so that the retaining body is pressed against one or more lower bars of the rotor winding head. During operation, the upper and lower bars of the rotor winding head, which generally consist of copper or contain copper and therefore also expand in the axial direction, heat up. As explained, the body of Petition 870230061400, dated 07 / 13 / 2023, page 20 / 59 14 / 24 The retaining element can be rigidly axially connected to the laminated core, in particular by means of screws, and can be subjected to axial expansion that deviates from the winding head, particularly to a lesser extent. In order to avoid damage during relative movement between the retaining element and the lower bars in the axial direction, as well as thermal stresses, it is preferably provided that a sliding device is disposed between the retaining element and the lower bars, which has on at least one side a surface formed by a material with a low coefficient of friction, in particular by a Teflon-Carbon plate. The sliding device is also advantageously designed as a component that surrounds the rotor shaft.

[0051] Advantageously, the sliding device is rigidly connected to the lower bars and movable axially to the retaining body. The sliding device generally slides with that surface which is formed by a material with a low coefficient of friction on the retaining body or a component rigidly connected to it.

[0052] The sliding device preferably has a sliding layer formed from a material with a low coefficient of friction, in particular a Teflon-carbon plate with a radial height of 1 mm to 20 mm, in particular 2 mm to 10 mm.

[0053] It may also be advantageous if the sliding device has a layer formed from a paramagnetic material, in particular aluminum or a hard glass fabric of epoxy resin, in which holes penetrating the layer in the axial direction are preferably provided. Ventilation of the rotor winding head can also be improved in this area through the holes. The layer generally extends completely around the rotor axis in the circumferential direction and thus separates the retaining body, which may consist of a ferromagnetic material or have such a material, from the lower bars. Petition 870230061400, dated 07 / 13 / 2023, p. 21 / 59 15 / 24 across the entire circumference.

[0054] To avoid leakage currents, it may be advantageous for the sliding device to have a metal layer separated from the lower bars by an insulating layer rigidly connected to the metal layer, the insulating layer having, in particular, an epoxy resin fiberglass fabric.

[0055] This insulating layer also allows the sliding device to be supported on the lower bars.

[0056] Other features, advantages and effects of the invention result from the embodiments shown below. Shown in the drawings to which reference is made:

[0057] Figures 1 and 2 show details of a rotor according to the invention;

[0058] Figure 3 shows a U-shaped fastener;

[0059] Figure 4 shows part of a rotor;

[0060] Figure 5 shows an additional detail of a rotor;

[0061] Figure 6 shows a detail of a sliding device;

[0062] Figure 7 shows another detail of a rotor in an exploded view;

[0063] Figure 8 is a plan view of a rotor;

[0064] Figure 9 shows a detail of another rotor;

[0065] Figures 10 and 11 show a detail of another rotor.

[0066] Figures 1 to 3 show a region of a winding head of a rotor according to the invention, showing part of a laminated core 1 together with a pressure plate 30 disposed at the end of the laminated core 1. As can be seen, the rotor has 4 upper bars and 3 lower bars, which are arranged in slots 2 in the laminated core 1 and are connected outside the laminated core 1, whereby, as in such machines, which can be conceived as asynchronous machines, a lower bar 3 of a slot Petition 870230061400, dated 07 / 13 / 2023, page 22 / 59 16 / 24 is generally always connected to an upper bar 4 of another slot 2, in this case by bar connectors 29 arranged axially at the ends of the upper bars 4 and lower bars 3.

[0067] While the upper bars 4 and lower bars 3 in the laminated core area extend only in the axial direction 5 here, the upper bars 4 and lower bars 3 also extend axially outside the laminated core 1 or in the winding head area along a circumferential direction 7 to create a connection between an upper bar 4 and a lower bar 3 with two slots 2 spaced in the circumferential direction 7. In the embodiment shown, the upper bars 4 extend at an angle of approximately 45° relative to the rotor axis 23 or in the axial direction 5, which is parallel to the rotor axis 23, in the circumferential direction 7, while the lower bars 3 extend approximately opposite at an angle of approximately -45° relative to the rotor axis 23 in the circumferential direction 7.

[0068] As can be seen in Figure 2, the upper bars 4 cross the lower bars 3 at an angle of approximately 90° at the crossing points 8. 6 gaps remain between the crossing points 8 in the top view shown in Figure 2 or when viewed in the radial direction 9. Through some of these openings 9, the rods 12 of the U-shaped fastener 11 protrude, which radially support the winding head, insofar as a connecting piece 13 connecting the rods 12 of the U-shaped fastener 11 spans two upper bars 4 on the outside, as shown, and thus radially couples them to a retaining body 10 disposed inside the winding head. One of these U-shaped fasteners 11, together with a spacer 28, is hidden in Figure 2, so that it can be seen that each of the U-shaped fasteners 11 overlaps two upper bars 4 and two bars Petition 870230061400, dated 07 / 13 / 2023, page 23 / 59 17 / 24 lower 3 and a gap 9 positioned between them.

[0069] For radial U-shaped fastener of U-shaped fastener 11, a locking element 15 is provided radially inside the winding head on the rods 12 of each U-shaped fastener 11, which has two through holes through which the rods 12 project and whose locking element 15 rests against an inner diameter 14 of the retaining body 10, which is here designed in the form of a ring, to mechanically couple the retaining body 10 to the upper rods 4 through the locking element 15 and the U-shaped fastener 11. The locking element 15 is fastened to the rods 12 by nuts 16.

[0070] The connecting pieces 13 are mechanically coupled to the upper bars 4, which pass through them, here indirectly through a spacer 28, which serves to avoid pressure peaks on the upper bars 4. Thus, a radial rigidity of the winding head is increased by the U-shaped fastener 11, which connects the annular retaining body 10 to the upper bars 4 and indirectly through the upper bars 4 also to the lower bars 3, which is why the U-shaped fastener 11 together with the retaining body 10 form U-shaped fastening devices for the winding head.

[0071] In the embodiment shown, three retaining bodies 10 are arranged in the axial direction 5 and three rows of U-shaped fasteners 11 are also provided accordingly along the axial direction 5, each row having U-shaped fasteners 11 distributed in a circumferential direction 7. The connecting pieces 13 of the U-shaped fastener 11 extend here in the axial direction 5. As shown, the connecting pieces 13 respectively span two upper bars 4 here, so that the rods 12 of the U-shaped fastener 11 are arranged in gaps 9 that join to Petition 870230061400, dated 07 / 13 / 2023, page 24 / 59 18 / 24 different top bars 4. Obviously, U-shaped fasteners 11 can also span more than two top bars 4 or more than one gap 9.

[0072] As a result, despite the crossing angle of the upper bars 4 and lower bars 3 of approximately 90°, which here in connection with comparatively narrow upper bars 4 and lower bars 3 leads to a small axial spacing of the gaps 9, a large spacing of the rods 31 is obtained between the rods 12 of the U-shaped fastener 11. This corresponds to at least twice the distance between two axially adjacent gaps 9.

[0073] The rods 12 extend as shown here exclusively in the radial direction 6, in order to achieve a tensile load essentially exclusive to the rods 12. The retaining body 10 is arranged between two rods 12 of a U-shaped fastener 11, and this is why a large rod spacing 31 results in a correspondingly large retaining body 10, which can absorb corresponding forces.

[0074] The three retaining bodies 10 arranged in different axial positions are designed here as circumferential rings and can thus prevent inadmissible deformations of the rotor winding head due to coupling through the U-shaped fastener 11 or absorb centrifugal forces that occur. For this purpose, the rods 12 of the U-shaped fastener 11 are radially coupled inside the retaining bodies 10 through a locking element 15.

[0075] The terms axial direction 5, radial direction 6 and circumferential direction 7 should be understood here in the sense of a cylindrical coordinate system, wherein the axial direction 5 coincides with a rotor axis 23, around which the rotor is rotatably arranged in a stator during normal operation or is parallel to this rotor axis 23. Consequently, the circumferential direction 7 corresponds to a Petition 870230061400, dated 07 / 13 / 2023, page 25 / 59 19 / 24 direction of rotation along which the rotor rotates in the stator during normal operation.

[0076] Figure 3 shows a U-shaped clamp 11 of a corresponding support device in detail, which here has the shape of a U. As can be seen, the U-shaped clamp 11 has two approximately parallel rods 12 that are connected by a connecting piece 13 aligned perpendicularly to the rods 12. The threads are generally arranged at the ends of the rods 12 so that the fastening element 15 can be fixed to the U-shaped clamp 11 by means of two nuts 16. The threads are preferably produced by thread cylinder or thread roll, in order to ensure high strength also in the thread area. The U-shaped clamp 11 is generally formed from a cold-drawn austenitic steel, whereby favorable magnetic properties are achieved for use in the winding head area and, at the same time, high strength.

[0077] Between the rods 12 of the winding head, the retaining body, preferably ring-shaped, 10 is generally disposed within the winding head, for which reason an axial extension of the retaining body 10, not shown in Figure 3, which can be designed as a ring retainer, for example, and a cross-section thereof through a rod spacing 31 can be defined. In the design of a corresponding rotor according to the invention, a comparatively large rod spacing 31 is achieved even with gaps 9 situated close to each other, especially since the rods 12 project through gaps 9 that join different upper bars 4 and lower bars 3, so that between the gaps 9 through which the rods 12 project, at least one other gap 9 is generally disposed, which is traversed by the connecting piece 13. Petition 870230061400, dated 07 / 13 / 2023, p. 26 / 59 20 / 24

[0078] Figure 4 shows a rotor in an isometric view. As can be seen, the rotor has a rotor body with arms 21 that are distributed around a rotor shaft 23 and between which are positioned openings 22. Air can be transported to an inner radius of the laminated core through these openings 22 to ventilate or cool it. The laminated core 1 is compressed into the arms 21 of the rotor body to form a stable connection between the laminated core 1 and the rotor body.

[0079] Figure 5 shows a detail of a rotor in an additional view. The retaining bodies 10 are generally connected in an essentially rigid manner to the rotor's laminated core in the axial direction 5 by means of screws (not shown). The lower rods 3 and the upper rods 4 are subject to heating and therefore thermal expansion during operation, which causes relative movement in the axial direction 5 between the lower rods 3 and the upper rods 4 on the one hand and the retaining bodies 10 on the other hand. To prevent this relative movement from leading to damage, particularly to the insulation of the lower rods 3, sliding devices 24 are arranged between the retaining bodies 10 and the lower rods 3.

[0080] Figure 6 shows a detail of such a sliding device 24 which can be rigidly connected to the lower bars 3. The sliding device 24 has a surface on the radially inner side which is formed of a material with a low coefficient of friction, usually a Teflon-carbon plate 25 which can support the retaining body 10. This Teflon-carbon plate 25 thus allows a relative low-friction movement between the lower bars 3, with which the sliding device 24 is usually coupled in the axial direction 5, and the corresponding adjacent retaining body 10.

[0081] The retaining body 10 usually has a magnetic material or may consist of fine-grained steel or similar. To minimize the Petition 870230061400, dated 07 / 13 / 2023, p. 27 / 59 21 / 24 magnetic losses in the winding head area, it is preferably provided that the sliding device 24 has a layer 26 which is formed of a paramagnetic material, in particular aluminum or hard glass fabric of epoxy resin. This layer 26 thus ensures a spacing between the magnetic retaining body 10 or a magnetic part of the retaining body 10 and the lower bars 3. To prevent leakage currents, an insulating layer 27 is disposed on the outside of the sliding device 24, which may consist, for example, of hard glass fabric of epoxy resin. If the layer 26 consists of an insulating material, the insulating layer 27 may also be formed in one piece with the layer 26 and may consist, for example, of hard glass fabric of epoxy resin.

[0082] Fine grain steel can thus form an inner ring of the retaining body 10, while the layer 26 made of aluminum or the sliding device can form an outer ring, the outer ring ensuring a distance between the lower bars 3 and the inner ring and at the same time supporting the inner ring in the radial direction connecting the lower bars 3.

[0083] Figure 7 shows an exploded view of three retaining bodies 10 and part of the laminated core 1. Each of the retaining bodies 10 has guide pins 19 and radial grooves 18, which extend along the radial direction 6, so that radial guides are provided and the individual retaining bodies 10 can be moved radially relative to each other due to the radial guides, but are kinematically coupled to each other in the circumferential direction 7. Corresponding radial grooves 18 are also provided on the pressure plate 30, not shown here, so that the retaining bodies 10 can also be moved radially relative to the pressure plate 30, but are connected in positive union to the pressure plate 30 in the circumferential direction 7. In the axial direction 5, the bodies of Petition 870230061400, dated 07 / 13 / 2023, page 28 / 59 22 / 24 retaining 10 are, as explained, generally rigidly coupled to the laminated core 1 by means of screws (not shown), it being possible that these screws extend from the pressure plate 30 to a more external axial retaining body 10.

[0084] Figure 8 shows a top view of the rotor, the torsion-free areas 20 of the rotor are indicated schematically by dashed and dotted lines, along which the radial guide devices, usually radial grooves 18 and corresponding guide pins 19 are arranged. These torsion-free areas 20 of the laminated core 1 and the pressure plate 30 are arranged in positions in the middle of the rotor body arms 21 and in the middle between these arms 21. By arranging the radial guides, which may be formed by grooves 2 and corresponding guide pins 19 or similar, torsion of the guides when the retractable adjustment is partially opened or closed during operation is easily avoided, especially since the rotor laminated core and the rotor pressure plate 30 are only radially deformed in these areas.

[0085] Figure 9 shows a detail of another embodiment, in which a radially internal end of support devices is illustrated. Here too, a locking element 15 is radially provided inside the U-shaped fastener 11, by means of which the U-shaped fastener 11 is closed and coupled to the retaining body 10. Here too, the rods 12 of the U-shaped fastener 11 are guided through the locking element 15, and nuts 16 are screwed onto the ends of the rods 12 to fix the locking element 15 to the U-shaped fastener 11. Furthermore, between the nuts 16 and the locking elements 15, spring elements designed as disc springs 17 are provided, with three disc springs 17 positioned in series between the nuts 16 and the locking element 15. As a result, a predefined pre-tensioning can be Petition 870230061400, dated 07 / 13 / 2023, page 29 / 59 23 / 24 introduced into rods 12, which can be held in place by means of spring elements even during the settling process. As a result, readjustment of nuts 16 after rotor operation can be avoided.

[0086] Figures 10 and 11 show another example of a detailed embodiment, again showing a radially internal end of a support device. Here too, the rods 12 of the U-shaped fastener 11 are guided through the fastening element 15, and the nuts 16 are screwed onto the ends of the rods 12 to secure the fastening element 15 to the U-shaped fastener 11. In addition, spring elements are also provided here, connecting the U-shaped fasteners 11 to the fastening element 15 via the nuts 16, additional steel washers 33 being disposed here between the spring elements and the nuts 16. Figure 10 shows the detail in isometric view, while Figure 11 shows a sectional view.

[0087] As can be seen in Figure 11, the spring elements, which are here conceived as helical disc springs 34, are arranged concentrically to the U-shaped fasteners 11, and a sleeve 35 is arranged parallel to the helical disc springs 34, here inside the helical disc springs 34, which is used as a stop. By means of the sleeve 35, the spring elements can thus be easily pre-tensioned to a defined deformation or a defined pre-tension, in which deformation of the helical disc springs 34 the steel discs 33 rest against the sleeves 35 respectively. The selected pre-tension thus defines the dimensions of the sleeves 35 together with the spring elements and can be selected, for example, so that the winding head is reliably prevented from lifting from the support device up to the machine's rated speed. If the speed exceeds the rated speed, the Petition 870230061400, dated 07 / 13 / 2023, page 30 / 59 24 / 24 which can occur in case of failure, for example, the 35 sleeves reliably prevent damage to the spring elements, especially since the 35 sleeves, which act as a stop, prevent excessive and inadmissible deformation of the spring elements.

[0088] Figures 10 and 11 also show an anti-rotation lock for the nuts 16, which is positively connected to both nuts 16 to prevent the nuts 16 from being unintentionally loosened during operation. In the embodiment shown, both the anti-rotation lock 32 and the support device are made of EPGC, although other materials are also possible.

[0089] A rotor according to the invention allows the stiffening of winding heads in corresponding machines in a robust manner, even when a gap distance 9 in the winding head area is very small due to the design. Corresponding machines can be used in particular in reversible hydroelectric power plants. Petition 870230061400, dated 07 / 13 / 2023, page 31 / 59

Claims

1 / 5 CLAIMS 1. Rotor for electric machine, having a laminated core (1) with slots (2) in which lower bars (3) and upper bars (4) are arranged, which extend in the axial direction (5) beyond the laminated core (1) to form a winding head extension, with a lower bar (3) of one slot (2) being connected to an upper bar (4) of another slot (2) in the winding head and the lower bars (3) and the upper bars (4) intersecting axially outside the laminated core (1) in a plan view at the crossing points (8) and gaps (9) remaining between the crossing points (8), wherein a support device is provided having a retaining body (10) radially arranged inside the winding head and at least one U-shaped fastener (11) with two rods (12) and a connecting piece (13),wherein the U-shaped fastener (11) is connected both to the retaining body (10) and to an upper bar (4) to radially support the upper bar (4) by means of the retaining body (10), characterized in that the rods (12) project through two openings (9) adjacent to different upper bars (4).

2. Rotor, according to claim 1, characterized in that the connecting piece (13) is radially arranged outside the upper bars (4) and is connected to at least two upper bars (4).

3. Rotor, according to either of claims 1 or 2, characterized in that the retaining body (10) is designed in an annular shape and the rods (12) project to an inner diameter (14) of the retaining body (10).

4. Rotor, according to any one of claims 1 to 3, characterized in that a detachable closing element (15) is provided with the connected rods (12). Petition 870230061400, dated 13 / 07 / 2023, p. 32 / 59 2 / 5 5. Rotor, according to claim 4, characterized in that the retaining body (10) is connected to the U-shaped fastener (11) through the locking element (15).

6. Rotor, according to any one of claims 4 or 5, characterized in that the closing element (15) has radial through holes through which the rods (12) protrude, wherein fastening elements, in particular nuts (16), are provided downstream of the rods (12) and the closing element (15), which fasten the closing element (15) to the rods (12).

7. Rotor, according to claim 6, characterized in that spring elements, in particular disc springs (17), are arranged between the fastening elements and the locking element (15), which are preferably pre-tensioned with a predefined pre-tensioning force.

8. Rotor, according to any one of claims 1 to 7, characterized in that the rods (12) have threads that are preferably formed by thread rolling.

9. Rotor, according to any one of claims 1 to 8, characterized in that the U-shaped fastener (11) is formed from an austenitic material.

10. Rotor, according to any one of claims 1 to 9, characterized in that the U-shaped fastener (11) is formed from a cold-machined metal, in particular a cold-drawn steel.

11. Rotor, according to any one of claims 1 to 10, characterized in that the retaining body (10) is made of a ferritic material, in particular a ferritic steel, or is formed from such a material.

12. Rotor, according to any one of claims 1 to 11, characterized in that the retaining body (10) is made of fine-grained steel. Petition 870230061400, dated 13 / 07 / 2023, page 33 / 59 3 / 5 13. Rotor, according to any one of claims 1 to 12, characterized in that the retaining body (10) has a ferritic inner part and a non-magnetic outer part, consisting mainly of aluminum, a fiber composite material or a hard fabric, for example glass hard fabric and epoxy resin.

14. Rotor, according to any one of claims 1 to 13, characterized in that the retaining body (10) is rigidly connected to the laminated core (1) in the axial direction (5).

15. Rotor, according to any one of claims 1 to 14, characterized in that the retaining body (10) is connected to the laminated core (1) so that it can move in the radial direction (6), in particular by means of a radial guide.

16. Rotor, according to any one of claims 1 to 15, characterized in that a component rigidly connected to the laminated core of the rotor, in particular a pressure plate (30), has first guide means, in particular radial grooves (18), which extend in the radial direction (6) and the retaining body (10) corresponding to the second guide means, in particular guide pins (19), which engage in the first guide means, so that the retaining body (10) can be moved in the radial direction (6) by the interactive guide means and is rigidly connected to the laminated core (1) in the circumferential direction (7).

17. Rotor, according to claim 16, characterized in that several, in particular three, retaining bodies (10) are provided in the axial direction (5), which are kinematically coupled through radial guide means in the circumferential direction (7) and can be moved relative to each other in the radial direction (6), wherein the radial guide means are preferably formed by radial grooves (18) and corresponding guide pins (19) that fit into the radial grooves (18).

18. Rotor, according to claim 17, characterized in that the retaining bodies (10) are axially connected to the pressure plate (30) by screws, the screws extending continuously from an axially external retaining body (10) to the pressure plate (30), and in particular under a defined pre-tensioning.

19. Rotor, according to any one of claims 16 to 18, characterized in that the rotor has a rotor body with arms (21) distributed along a circumferential direction (7) and openings (22) disposed between the arms (21) through which cooling air can be fed to the laminated rotor core, wherein the laminated core (1) is shrunk into the rotor body, wherein the first guide means, which extend radially, are disposed along a circumferential direction (7) in positions that correspond to the positions of the arms (21) in the area of ​​a pressure plate (30) and / or correspond to positions in the middle between the arms (21) in the area of ​​the pressure plate (30).

20. Rotor, according to any one of claims 1 to 19, characterized in that the ribs (13) are oriented approximately parallel to the axial direction (5).

21. Rotor, according to any one of claims 1 to 20, characterized in that several U-shaped fasteners (11) are distributed along a circumferential direction (7).

22. Rotor, according to any one of claims 1 to 21, characterized in that several U-shaped fasteners (11) are provided in the axial direction (5).

23. Rotor, according to any one of claims 1 to 22, characterized in that the retaining body (10) encloses a rotor shaft (23) and is specially designed in the form of a plate. Petition 870230061400, dated 13 / 07 / 2023, p. 35 / 59 5 / 5 24. Rotor, according to any one of claims 1 to 23, characterized in that a sliding device (24) is disposed between the retaining body (10) and the lower bars (3), which has a surface on at least one side that is formed by a material with a low coefficient of friction, in particular by a Teflon-carbon plate (25).

25. Rotor, according to claim 24, characterized in that the sliding device (24) is rigidly connected to the lower bars (3) and is movably axially connected to the retaining body (10).

26. Rotor, according to any one of claims 24 or 25, characterized in that the sliding device (24) has a sliding layer formed of a material with a low coefficient of friction, in particular a Teflon-carbon plate (25) with a radial height of 1 mm to 20 mm, in particular 2 mm to 10 mm.

27. Rotor, according to any one of claims 24 to 26, characterized in that the sliding device (24) has a layer (26) that is formed of a paramagnetic material, in particular aluminum or a hard glass fabric of epoxy resin, in which holes penetrating the layer (26) in the axial direction (5) are preferably provided.

28. Rotor, according to any one of claims 24 to 27, characterized in that the sliding device (24) has a metal layer (26) which is separated from the lower bars (3) by an insulating layer (27) rigidly connected to the metal layer (26), wherein the insulating layer (27) has, in particular, hard glass fabric of epoxy resin. Petition 870230061400, dated 13 / 07 / 2023, p. 36 / 59

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