Rotor

Abstract

The invention relates to a rotor (1) for an electrical machine. The rotor (1) has a shaft (2), a rotor core (3), and two end caps (4). The end caps (4) have a plurality of radially outwardly directed winding head supports (7), each with a radially outer outer wall (8). The outer wall (8) has an outer surface (8b) that is inclined radially inward. The invention also relates to an electrical machine with the rotor (1) and a stator.

Description

[0001] The invention relates to a rotor for an electrical machine, in particular for a separately excited synchronous machine for a vehicle, according to the preamble of claim 1. The invention also relates to the electrical machine, in particular a separately excited synchronous machine, with the rotor.

[0002] An electrical machine, in particular a separately excited synchronous machine, typically comprises a rotor and a stator, with the rotor being accommodated coaxially in the stator so as to be rotatable about a rotational axis. The rotor comprises a shaft and a rotor core fixedly mounted on the shaft. Furthermore, the rotor typically has two end caps and several windings carried by the end caps. The end caps are star-shaped and comprise several winding head supports evenly distributed around the rotational axis, on which the windings or winding heads of the windings are then arranged. The respective winding head support is usually U-shaped to hold the windings. The end caps can be made of different materials, such as plastic or metal.

[0003] Under load—for example, at high rotor speeds and / or at high circumferential speeds—a high centrifugal force acts on the respective winding head carrier due to its high mass. Under the effect of this centrifugal force, the windings on the winding head carrier shift radially outward, which leads to a larger outer radius of the windings and further amplifies the effect. In addition, the wire of the respective winding is subjected to an additional tangential force. This tangential force must be absorbed by a potting compound or other components of the rotor to prevent the windings from failing under load.

[0004] EP 2 594 009 A1 discloses a rotor for an electrical machine. The rotor comprises an end cap with a winding head support, which is radially supported outwardly by a support ring. This prevents deformation of the winding head support and sliding of the windings from the winding head support under load.

[0005] The object of the invention is therefore to provide an improved or at least alternative embodiment for a rotor of the generic type, in which the described disadvantages are overcome. The object of the invention is also to provide an electrical machine with such a rotor.

[0006] This object is achieved according to the invention by the subject matter of the independent claims. Advantageous embodiments are the subject matter of the dependent claims.

[0007] The present invention is based on the general idea of ​​forming at least one radially outer side part of the winding head carrier on its outer surface inclined relative to the axis of rotation in order to achieve the desired axial force ratios and thereby compensate in advance for bending of the winding head carrier under the effect of centrifugal force.

[0008] The rotor according to the invention is provided or designed for an electrical machine, in particular a separately excited synchronous machine for a vehicle. The rotor has a shaft rotatable about a rotational axis and a rotor core with two opposite axial longitudinal ends. The rotor core is connected to the shaft in a rotationally fixed manner. In addition, the rotor has two star-shaped end caps with several radially outwardly directed winding head supports for supporting windings of the rotor. The end caps are fixed to the axial longitudinal ends of the rotor core. Each end cap has a base surface oriented transversely to the rotational axis (radially), and the respective winding head support has a radially outward outer wall. The outer wall protrudes from the base surface of the end cap in a direction opposite to the rotor core and has a radially outward outer surface.According to the invention, the outer surface of the outer wall is inclined away from the rotor core and obliquely inward, at least in some regions. The outer surface can be inclined away from the rotor core and radially / obliquely inward over the entire axially defined height of the outer wall or at least over more than 50%, preferably over more than 75%, of the axially defined height of the outer wall. The outer wall of the respective winding head carrier can, in particular, be inclined such that an outer radius of the end cap on the outer wall of the respective winding head carrier always remains smaller than an outer radius of the rotor core under the effect of the centrifugal force on the rotor.

[0009] In the context of the present invention, the terms “axial” and “radial” and “circumferential” and “tangential” always refer to the axis of rotation of the shaft. The term “axial” is used synonymously with the formulation “in a direction axial with respect to the axis of rotation” and / or “in a direction aligned along the axis of rotation”. The term “radial” is used synonymously with the formulation “in a direction radial with respect to the axis of rotation”. The term “circumferential” is used synonymously with the formulation “in a direction circumferential to the axis of rotation”. The term “tangential” is used synonymously with the formulation “tangential to a line circumferential to the axis of rotation”.

[0010] Under load - such as at high rotor speeds and / or at high circumferential speeds of the rotor - a high centrifugal force acts on the respective winding head carrier due to the high mass. Under the effect of the centrifugal force, the windings on the winding head carrier shift radially outwards and, due to the high mass of the respective winding, the outer wall of the respective winding head carrier bends radially outwards. The outer surface of the outer wall of the respective winding head carrier is inclined radially / obliquely inwards, whereby even when the outer wall is deformed radially outwards, the outer radius of the end cap remains smaller than the outer radius of the rotor core. This advantageously prevents contact between the rotor and the stator in the area of ​​the end caps.In other words, the increase in the outer radius of the end caps under the effect of centrifugal force on the rotor can be compensated in advance by inclining the outer surface of the outer wall of the respective winding head support. The deformation or upward bending of the outer wall of the respective winding head support can therefore be permitted and planned for during the design of the end cap. This eliminates the need for other conventional aids, such as a support ring enclosing the winding head support from the outside. The inclined outer surface of the outer wall allows the space required by the rotor yoke to be utilized.

[0011] The respective end cap can, for example, be formed from a non-ferromagnetic material, preferably from metal and / or plastic, or from a ferromagnetic material, such as metal.

[0012] The outer surface of the outer wall can be inclined towards the axis of rotation, in particular along a direction axially opposite to the rotor core. The outer surface can have an angle greater than zero to the axis of rotation, at least in some regions—i.e., over the entire axially defined height of the outer wall or at least over more than 50%, preferably over more than 75%, of the axially defined height of the outer wall. The angle can be, in particular, between 5° and 20°, preferably between 10° and 15°. The outer surface can have a constant angle to the axis of rotation, or alternatively a changing angle to the axis of rotation, at least in some regions along its axial profile—i.e., over the entire axial profile or at least over more than 50%, preferably over more than 75%, of the axial profile. The end cap can have a continuously changing outer radius on the outer wall.The outer radius of the end cap can always decrease, especially away from the rotor core.

[0013] An axial profile of the outer surface of the outer wall of the respective winding head support can, for example, be represented by a straight line, a continuous curve, or a parabola, at least in some regions—i.e., over the entire axially defined height of the outer wall or at least over more than 50%, preferably over more than 75%, of the axially defined height of the outer wall. An axial profile of the outer surface of the outer wall of the respective winding head support can be shaped such that, under the effect of centrifugal force on the rotor, the axial profile is represented by a straight line, at least in some regions—i.e., over the entire axially defined height of the outer wall or at least over more than 50%, preferably over more than 75%, of the axially defined height of the outer wall.In other words, the axial profile can be shaped such that an axial profile of the outer surface, originally represented by a curve, becomes straight under the action of the centrifugal force on the rotor within a defined rotor speed range. This allows even an outer radius of the end cap that originally deviates along the axial profile of the outer surface to remain constant under the action of the centrifugal force on the rotor within a defined rotor speed range. The defined rotor speed range can, for example, be between 8,000 and 9,000 revolutions per minute.

[0014] The respective end cap and / or the respective winding head support of the respective end cap and / or the outer wall of the respective winding head support can be shaped such that an angle formed between the respective outer wall and the rotation axis can decrease under the effect of the centrifugal force on the rotor. In other words, the deformation or bending of the outer wall of the respective winding head support can already be permitted and planned for when the end cap is designed. The respective end cap and / or the respective winding head support of the respective end cap and / or the outer wall of the respective winding head support can be shaped such that an angle formed between the outer wall and the rotation axis under the effect of the centrifugal force on the rotor is zero in a defined rotor speed range. The defined rotor speed range can, for example, be in a range between 8,000 and 9,000 revolutions per minute.As already described above, the angle can in particular be between 5° and 20°, preferably between 10° and 15°.

[0015] The respective end cap and / or the respective winding head support of the respective end cap and / or the outer wall of the respective winding head support can be shaped such that the outer wall of the respective winding head support can bend radially outward under the effect of the centrifugal force on the rotor. The outer wall of the respective winding head support can be deformed radially outward under the effect of the centrifugal force on the rotor. This can be achieved, for example, by correctly selecting the material of the respective end cap and / or by correctly selecting the thickness of the outer wall of the respective winding head support and / or by correctly selecting the axial profile of the outer wall of the respective winding support.

[0016] The respective end cap can be shaped such that the ends of the outer walls of the respective winding head supports opposite the rotor core are free. The respective end cap can be shaped such that the outer walls of the respective winding head supports can be freely moved radially outwards under the action of the centrifugal force on the rotor. The respective end cap can be shaped such that the outer walls of the respective winding head supports can be freely deformed under the action of the centrifugal force on the rotor. In other words, the respective end cap can be shaped such that deformation or bending of the outer wall of the respective winding head support is not prevented. In particular, no support ring can be provided to surround the respective winding head support from the outside. This can also prevent problems caused by eddy currents generated in the support ring.The increase in the outer radius of the end caps over the outer radius of the rotor core caused by the effect of centrifugal force can be prevented solely by the inclination of the outer surface of the outer wall of the respective winding head support.

[0017] In a further embodiment of the rotor, it can be provided that the outer wall of the respective winding head carrier has a radially inward inner surface. In other words, the inner surface is arranged facing away from the outer surface of the outer wall and / or facing the rotor axis of the shaft. The inner surface of the outer wall is inclined axially away from the rotor core and radially inward. The inner surface can be inclined away from the rotor core and radially inward over the entire axially defined height of the outer wall or at least over more than 50%, preferably over more than 75%, of the axially defined height of the outer wall. The inner surface of the outer wall can in particular be inclined towards the axis of rotation in a direction axially opposite to the rotor core.In other words, the inner surface can have an angle greater than zero to the axis of rotation at least in some regions - i.e., over the entire axially defined height of the outer wall or at least over more than 50%, preferably over more than 75%, of the axially defined height of the outer wall. The angle can be, in particular, between 5° and 20°, preferably between 10° and 15°. The inner surface can have a constant angle to the axis of rotation at least in some regions along its axial profile - i.e., over the entire axially defined height of the outer wall or at least over more than 50%, preferably over more than 75%, of the axially defined height of the outer wall. An axial profile of the inner surface can be represented by a straight line at least in some regions - i.e., over the entire axially defined height of the outer wall or at least over more than 50%, preferably over more than 75%, of the axially defined height of the outer wall.

[0018] Due to the inclined inner surface of the outer wall, the winding can be wound using a conventional machine with only minimal additional effort in the movement sequence due to the winding heads not being fully accessible axially. Due to the inclined inner surface of the outer wall, the winding is located on a smaller radius for a constant outer radius of the end cap and, due to a lower peripheral speed, also experiences a smaller centrifugal force. Furthermore, an additional tangential force in a tangentially outward direction experienced by the wire of the respective winding is no longer directed outwards and, depending on the design of the inner surface of the outer wall, can even disappear completely. This can further stabilize the winding.

[0019] In a further embodiment of the rotor, it can be provided that the respective winding head carrier has an inner wall that is located radially inward with respect to the outer wall and projects from the base surface of the end cap opposite the rotor core. The inner wall can have an inner surface facing the outer wall, and the inner surface can be inclined away from the rotor core and radially inward. The inner surface can be inclined away from the rotor core and radially inward over the entire axially defined height of the inner wall or at least over more than 50%, preferably over more than 75%, of the axially defined height of the inner wall. In other words, the inner surface can have an angle greater than zero to the axis of rotation, at least in some regions - i.e. over the entire axially defined height of the inner wall or at least over more than 50%, preferably over more than 75%, of the axially defined height of the inner wall.The angle can be, in particular, between 5° and 20°, preferably between 10° and 15°. The inner surface can have a constant angle to the axis of rotation at least in some areas along its axial profile—that is, over the entire axially defined height of the inner wall or at least over more than 50%, preferably over more than 75%, of the axially defined height of the inner wall. An axial profile of the inner surface can be represented by a straight line at least in some areas—that is, over the entire axially defined height of the inner wall or at least over more than 50%, preferably over more than 75%, of the axially defined height of the inner wall.

[0020] Various options are conceivable for the design of the respective winding head supports.

[0021] The outer surface of the outer wall and / or the inner surface of the outer wall and / or the inner surface of the inner wall can be aligned at least in some regions - i.e. over the entire axially defined height of the outer wall / inner wall or at least over more than 50%, preferably over more than 75%, of the axially defined height of the outer wall / inner wall - at a same angle greater than zero or each at a different angle greater than zero to the axis of rotation. The outer surface of the outer wall and / or the inner surface of the outer wall and / or the inner surface of the inner wall can be aligned non-parallel or parallel to one another, at least in some regions - i.e. over the entire axially defined height of the outer wall / inner wall or at least over more than 50%, preferably over more than 75%, of the axially defined height of the outer wall / inner wall.A radially defined thickness of the outer wall and / or a radially defined distance between the inner surface of the outer wall and the inner surface of the inner wall can change or be identical along the axis of rotation at least in regions - i.e. over the entire axially defined height of the outer wall / inner wall or at least over more than 50%, preferably over more than 75%, of the axially defined height of the outer wall / inner wall.

[0022] The invention also relates to an electrical machine, in particular a separately excited synchronous machine for a vehicle. The electrical machine comprises a rotor described above, a stator, and a housing. The rotor is coaxial and rotatable within the stator, and the stator is coaxial and non-rotatably received within the housing. To avoid repetition, reference is made to the above explanations at this point.

[0023] Further important features and advantages of the invention emerge from the subclaims, from the drawings and from the associated description of the figures with reference to the drawings.

[0024] It is understood that the features mentioned above and those to be explained below can be used not only in the combination specified in each case, but also in other combinations or on their own, without departing from the scope of the present invention.

[0025] Preferred embodiments of the invention are illustrated in the drawings and are explained in more detail in the following description, wherein the same reference numerals refer to the same or similar or functionally identical components.

[0026] They show, schematically Fig. 1 a sectional view of a rotor according to the prior art without the effect of centrifugal force; Fig. 2 a sectional view of the rotor according to the prior art under the action of centrifugal force; Fig. 3 a sectional view of a winding head carrier of the rotor according to the prior art under the action of centrifugal force; Fig. 4 a sectional view of a rotor according to the invention without the effect of centrifugal force; Fig. 5 a plan view of a rotor stack of the rotor according to the invention.

[0027] Fig. 1 shows a sectional view of a rotor 1' according to the prior art without the effect of centrifugal force or without load or in the rest state. In Fig. Figure 2 shows the rotor 1' according to the prior art under the action of centrifugal force, under load, or while rotating. The rotor 1' has a shaft 2' with a rotation axis RA', a rotor core 3' fixedly mounted on the shaft 2', and two end caps 4'. The end caps 4' are aligned transversely to the rotation axis RA' and are fixed to both axially opposite longitudinal ends 5' of the rotor core 3'.

[0028] The respective end cap 4' is star-shaped and has a base surface 6' and several - for example, exactly six - winding head supports 7'. The respective winding head support 7' is directed radially outwards and also has a radially outer wall 8' and a radially inner wall 9', both of which protrude from the base surface 6'. The winding head support 7' is thus partially formed by the outer wall 8', partially by the base surface 6', and partially by the inner wall 9'. The outer wall 8' has an inner surface 8a' facing the rotation axis RA' and an outer surface 8b' facing away from the rotation axis RA', and the inner wall 9' has an inner surface 9a' facing the outer wall 8'. Windings of the rotor 1' are wound on the winding head support 7', or winding heads 10' of the windings are arranged.

[0029] Without load, no centrifugal force acts on the respective winding head carrier 7'. Referring to Fig. 1, the inner surface 8a' and the outer surface 8b' of the outer wall 8' and the inner surface 9a' of the inner wall 9' are aligned perpendicular to the base surface 6' of the respective end cap 6' or parallel to the rotation axis RA'. An outer radius R_END' of the end cap 4' is equal to or smaller than an outer radius R_ROT' of the rotor core 3'.

[0030] Under load - such as at a high speed of the rotor 1' and at a high circumferential speed of the rotor 1' - a high centrifugal force acts on the respective winding head carrier 7' due to the high mass of the winding heads 10'. Referring to Fig. 2, the outer wall 8' and the inner wall 9' then deform or bend outward. As a result, the outer radius R_END' of the end cap 4' becomes larger than the outer radius R_ROT' of the rotor core 3'. To avoid this, a support ring—not shown here—is conventionally arranged around the winding head supports 7' of the end caps 3'. The support ring holds the outer wall 8' from the outside and prevents an increase in the outer radius R_END'.

[0031] Fig. Figure 3 shows a sectional view of the winding head support 7' of the rotor 1' according to the prior art under the effect of centrifugal force. As in Fig. It can be seen that under the action of the centrifugal force on the rotor 1', the coil head carriers 7' and the coil heads 10' move radially outwards. As a result, the coil heads 10' are arranged at a larger outer radius R_END' and thus amplify this effect, since higher circumferential speeds prevail at the larger outer radius R_END'. In addition, a total force F_RES acts on the wire of the coil heads 10', which is composed of a normal force F_N and an additional tangential force F_T in a tangentially outward direction. Therefore, the tangential force F_T must conventionally be intercepted by a potting or other components in order to avoid failure of the winding under load.

[0032] Fig. Figure 4 shows a sectional view of a rotor 1 according to the invention without the effect of centrifugal force, without load, or in the rest state. The rotor 1 here has a shaft 2 with a rotation axis RA, a rotor package 3 firmly seated on the shaft 2, and two end caps 4. The end caps 4 are oriented transversely to the rotation axis RA and are fixed to both axially opposite longitudinal ends 5 of the rotor package 3. Each end cap 4 is star-shaped and has a base surface 6 and several - for example, exactly six - winding head carriers 7. Each winding head carrier 7 is directed radially outwards and has a radially outer outer wall 8 and a radially inner inner wall 9, both of which project from the base surface 6. The winding head carrier 7 is thus shaped approximately U-shaped in sections by the outer wall 8, in sections by the base surface 6, and in sections by the inner wall 9.The outer wall 8 has a radially inner inner surface 8a and a radially outer outer surface 8b, and the inner wall 9 has an inner surface 9a facing the outer wall 8. Windings are wound on the winding head carrier 7, or winding heads 10 of the windings are arranged.

[0033] The outer surface 8b of the outer wall 8 is directed or inclined away from the rotor core 3 and radially inward. In this exemplary embodiment, the inner surface 8a of the outer wall 8 and the inner surface 9a of the inner wall 9 are also directed away from the rotor core 3 and radially inward. This is intended to mean inclined inward at an angle to the rotor axis RA. Without load, the outer surface 8b and the inner surface 8a of the outer wall 8 and the inner surface 9a of the inner wall 9 therefore have an angle greater than zero to the axis of rotation. Under the effect of centrifugal force, the outer wall 8 and the inner wall 9 can bend or deform outward. An increase in an outer radius R_END can be compensated for by the inclination of the outer surface 8b of the outer wall 8, so that the outer radius R_END always remains smaller than an outer radius R_ROT of the rotor core 3. This can advantageously prevent a collision of the rotor 1 with a stator.In addition, the conventional support ring is no longer necessary.

[0034] In Fig. 4, the outer surface 8b of the outer wall 8 and the inner surface 8a of the outer wall 8 and the inner surface 9a of the inner wall 9 each have an axial profile in the form of a straight line. It is conceivable that the axial profile of the outer surface 8b of the outer wall 8 and / or the inner surface 8a of the outer wall 8 and / or the inner surface 9a of the inner wall 9 is depicted by a curve and / or by a parabola. Fig. 4, an axial profile of the outer surface 8b of the outer wall 8 and the inner surface 8a of the outer wall 8 and the inner surface 9a of the inner wall 9 is identical over the entire axially defined height of the outer wall 3 and the inner wall 9, respectively. It is conceivable that an axial profile of the outer surface 8b of the outer wall 8 and / or the inner surface 8a of the outer wall 8 and / or the inner surface 9a of the inner wall 9 is only identical over more than 50%, preferably only over more than 75%, of the axially defined height of the outer wall 8 and the inner wall 9, respectively, and otherwise deviates therefrom. In other words, an axial profile of the outer surface 8b of the outer wall 8 and / or the inner surface 8a of the outer wall 8 and / or the inner surface 9a of the inner wall 9 can be represented by a combination of a straight line and / or a continuous curve and / or a parabola.

[0035] Fig.Figure 5 shows a top view of the rotor core 3 of the rotor 1 according to the invention. As can be seen particularly clearly here, the rotor core 3 is star-shaped and has six radially outwardly directed sections 11. These six radially outwardly directed sections 11 correspond in the rotor 1 to the winding head supports 7 of the respective end caps 4. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] EP 2 594 009 A1

[0004]

Claims

[1] Rotor (1) for an electrical machine, in particular for a separately excited synchronous machine for a vehicle, - wherein the rotor (1) has a shaft (2) rotatable about a rotation axis (RA) and a rotor package (3), - wherein the rotor core (3) is connected to the shaft (2) in a rotationally fixed manner and has two opposite axial longitudinal ends (5), - wherein the rotor (1) has two star-shaped end caps (4) with a plurality of radially outwardly directed winding head supports (7) for supporting windings of the rotor (1), - wherein the end caps (4) are fixed to the axial longitudinal ends (5) of the rotor core (3), - wherein the respective end cap (4) has a base surface (6) aligned transversely to the axis of rotation (RA) and the respective winding head carrier (7) has a radially outer outer wall (8), - wherein the outer wall (8) protrudes from the base surface (6) of the end cap (4) opposite the rotor core (3) and has a radially outer outer surface (8b), characterized by that the outer surface (8b) of the outer wall (8) is inclined axially away from the rotor core (3) and radially inwards. [2] Rotor (1) according to claim 1, characterized by that the outer wall (8) of the respective winding head carrier (7) is inclined in such a way that an outer radius (R_END) of the end cap (4) on the outer wall (8b) of the respective winding head carrier (7) is always smaller than an outer radius (R_ROT) of the rotor core (3) under the effect of the centrifugal force on the rotor (1). [3] Rotor (1) according to claim 1 or 2, characterized by , - that an axial profile of the outer surface (8b) of the outer wall (8) of the respective winding head carrier (7) is represented at least in some areas by a straight line or by a continuous curve or by a parabola, and / or - that an axial profile of the outer surface (8b) of the outer wall (8) of the respective winding head carrier (7) is shaped such that the axial profile is at least partially represented by a straight line under the effect of the centrifugal force on the rotor (1) in a defined speed range of the rotor (1). [4] Rotor (1) according to one of the preceding claims, characterized by , - that the respective end cap (4) and / or the respective winding head carrier (7) of the respective end cap (4) and / or the outer wall (8) of the respective winding head carrier (7) are shaped such that an angle formed between the outer surface (8b) of the respective outer wall (8) and the rotation axis (RA) can decrease under the effect of the centrifugal force on the rotor (1), and / or - that the respective end cap (4) and / or the respective winding head carrier (7) of the respective end cap (4) and / or the outer wall (8) of the respective winding head carrier (7) are shaped such that an angle formed between the outer surface (8b) of the respective outer wall (8) and the axis of rotation (RA) under the action of the centrifugal force on the rotor (1) is equal to zero in a defined speed range of the rotor. [5] Rotor (1) according to one of the preceding claims, characterized by , - that the respective end cap (4) and / or the respective winding head carrier (7) of the respective end cap (4) and / or the outer wall (8) of the respective winding head carrier (7) are shaped in such a way that the outer wall (8) of the respective winding head carrier (7) can bend radially outwards under the effect of the centrifugal force on the rotor (1), and / or - that the outer wall (8) of the respective winding head carrier (7) can be deformed radially outwards under the effect of the centrifugal force on the rotor (1). [6] Rotor (1) according to one of the preceding claims, characterized by , - that the respective end cap (4) is shaped in such a way that the ends of the outer walls (8) of the respective winding head supports (7) opposite the rotor core (3) are free, and / or - that the respective end cap (4) is shaped such that the outer walls (8) of the respective winding head supports (7) are freely movable radially outwards under the effect of the centrifugal force on the rotor (1), and / or - that the respective end cap (4) is shaped such that the outer walls (8) of the respective winding head supports (7) are freely deformable under the action of the centrifugal force on the rotor (1). [7] Rotor (1) according to one of the preceding claims, characterized by , - that the outer wall (8) of the respective winding head carrier (7) has a radially inner inner surface (8a), and - that the inner surface (8a) of the outer wall (8) is inclined axially away from the rotor core (3) and radially inwards. [8] Rotor (1) according to one of the preceding claims, characterized by , - that the respective winding head carrier (7) has an inner wall (9) which is radially inward relative to the outer wall (8) and projects from the base surface (6) of the end cap (4) in the opposite direction to the rotor core (3), and - that the inner wall (9) has an inner surface (9a) facing the outer wall (8) and the inner surface (9a) is inclined away from the rotor core (3) and radially inwards. [9] Rotor (1) according to one of the preceding claims, characterized by , - that the outer surface (8b) of the outer wall (8) and / or the inner surface (8a) of the outer wall (8) and / or the inner surface (9a) of the inner wall (9) are at least partially aligned at a different angle to the axis of rotation (RA), and / or - that the outer surface (8b) of the outer wall (8) and / or the inner surface (8a) of the outer wall (8) and / or the inner surface (9a) of the inner wall (9) are not aligned parallel to one another, at least in some areas. [10] Rotor (1) according to one of the preceding claims, characterized by that a radially defined thickness of the outer wall (8) and / or a radially defined distance between the inner surface (8a) of the outer wall (8) and the inner surface (9a) of the inner wall (9) change at least in regions along the axis of rotation (RA). [11] Rotor (1) according to one of the preceding claims, characterized by , - that the outer surface (8b) of the outer wall (8) and / or the inner surface (8a) of the outer wall (8) and / or the inner surface (9a) of the inner wall (9) are aligned at least in some areas at an equal angle greater than zero to the axis of rotation (RA), and / or - that the outer surface (8b) of the outer wall (8) and / or the inner surface (8a) of the outer wall (8) and / or the inner surface (9a) of the inner wall (9) are aligned parallel to one another at least in some areas. [12] Rotor (1) according to one of the preceding claims, characterized by that a radially defined thickness of the outer wall (8) and / or a radially defined distance between the inner surface (8a) of the outer wall (8) and the inner surface (9a) of the inner wall (9) along the axis of rotation (RA) are at least partially identical. [13] Electrical machine, in particular a separately excited synchronous machine for a vehicle, - wherein the electric machine comprises a rotor (1) according to one of the preceding claims, a stator and a housing, - wherein the rotor (1) is coaxially and rotatably received in the stator and the stator is coaxially and rotationally fixedly received in the housing.

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