Rotor for an electric machine, motor vehicle and method for manufacturing a rotor

Abstract

The invention relates to a rotor (10) for an electrical machine, which is designed to rotate in operation about an axis of rotation (16) which extends in an axial direction (A), the rotor comprising: a rotor lamination pack (14) comprising a plurality of rotor laminations which abut against one another in the axial direction (A); at least one sleeve (24) which extends in the axial direction (A) through an opening (22) of the rotor lamination pack (14) and which, with its outer wall, abuts in a circumferential manner against a wall of the rotor lamination pack (14) which delimits the opening (22); at least one tension anchor (26) which is inserted in the axial direction (A) through the sleeve (24) and which tension-tightens the rotor laminations against one another in the axial direction (A), the tension anchor (26) together with the sleeve (24) defining at least one cooling channel (36) which extends in the axial direction (A) within the sleeve (24), which extends in the axial direction (A) through the rotor lamination pack (14), and which can be flowed through by a cooling fluid.

Description

Technical Field

[0001] The present invention relates to a rotor for an electric motor, a motor vehicle, and a method for manufacturing the rotor. Background Technology

[0002] A modular system is known from DE102018215734A1 for manufacturing different structural schemes of rotors for motor vehicles. This modular system includes a rotor shaft spanning the structural schemes and lamination assemblies that can be mounted on and tortuously connected to the rotor shaft. The modular system includes at least one tensioning device separately from the rotor shaft and the lamination assemblies, by means of which the lamination layers of the lamination assemblies, arranged sequentially in the axial direction of the rotor shaft, can be tensioned to each other in the axial direction of the rotor shaft. The tensioning device includes at least two tension plates spaced apart from each other in the axial direction and at least one tension anchor connected to each tension plate and capable of being subjected to tension. A cooling channel is also provided, which is directly defined by the lamination assemblies and / or at least partially defined by the tensioning device, particularly by the tension anchor. Summary of the Invention

[0003] The objective of this invention is to provide a solution that allows for particularly reliable tensioning of multiple rotor laminations rotating from a lamination group, while simultaneously allowing for particularly efficient cooling of the lamination group.

[0004] The task described herein is solved by the subject matter of each independent claim. Other possible solutions to the invention are disclosed in the dependent claims, the specification, and the drawings. Features, advantages, and possible solutions set forth in the scope of the specification with respect to one of the subject matter of each independent claim can be at least similarly regarded as features, advantages, and possible solutions of the corresponding subject matter of the other independent claims, as well as features, advantages, and possible solutions of any possible combination of the subject matter of the independent claims (where necessary, in combination with one or more dependent claims).

[0005] This invention relates to a rotor for an electric motor, particularly a traction motor for a motor vehicle. The rotor is configured to rotate about an axis of rotation extending in the axial direction during operation. Specifically, the rotor is configured to rotate relative to the stator of the motor about the axis of rotation during motion. The motor is particularly a radial-flow motor. The rotor includes a rotor lamination assembly comprising a plurality of rotor laminations abutting each other in the axial direction. This means that the individual rotor laminations are stacked on top of each other in the axial direction and thus form the rotor lamination assembly. The rotor also includes at least one sleeve extending in the axial direction through an opening in the rotor lamination assembly and abutting its outer wall on the circumferential side against the wall of the rotor lamination assembly defining the opening. This means that the opening of the rotor lamination assembly is lined by the sleeve along its entire length extending in the axial direction. In particular, the sleeve is made of aluminum, thus enabling particularly good heat transfer between the sleeve and the stator lamination assembly. The rotor also includes at least one tension anchor inserted in the axial direction through the sleeve and tensioning the individual rotor laminations together in the axial direction. The tension anchor can be inserted into the sleeve, particularly with a radial clearance relative to the sleeve, thus allowing for particularly simple and effortless insertion. By applying pressure to the sleeve axially, especially when tensioning the rotor laminations of the rotor lamination assembly, the tension anchor can press the sleeve against the wall defining the opening of the rotor lamination assembly. This means that when the rotor laminations of the rotor lamination assembly are tensioned by means of the tension anchor, the tensioning sleeve is subjected to pressure in the axial direction, particularly compression, thus increasing the radial diameter of the sleeve. Due to the increased diameter of the sleeve extending in the radial direction, a reliable fit of the sleeve against the wall defining the opening of the rotor lamination assembly can be ensured. The radial direction of the sleeve is perpendicular to the axial direction of the rotor. The tension anchor may include a tensioning bolt and a nut tensioned at the free end of the tensioning bolt, or alternatively, a screw with nuts screwed onto respective ends of the screw. By screwing at least one nut onto the free end of the tension bolt or the mating end of the screw, the corresponding outermost rotor laminations of the rotor lamination assembly along the axial direction can be pressed against each other in the axial direction. Therefore, all the rotor laminations of the rotor lamination assembly arranged between these outermost rotor laminations are pressed against each other in the axial direction.

[0006] The tension anchor, together with the sleeve, defines at least one cooling channel extending within the sleeve, which extends axially through the rotor lamination assembly and is traversable by cooling fluid. By means of the cooling fluid flowing through the cooling channel, heat transferred from the rotor lamination assembly via the sleeve can be discharged, thus allowing for particularly good cooling of the rotor lamination assembly. Because both the tension anchor and the extending cooling channel are located within the opening of the rotor lamination assembly, particularly effective cooling of the rotor lamination assembly can be achieved in the region of the tension anchor, particularly reliable tensioning of the rotor laminations can be achieved by means of the tension anchor, and a particularly large fill weight of the rotor lamination assembly can be achieved, as only a volume specified by the opening is required for both cooling and tensioning. Furthermore, the sleeve allows for particularly good heat transfer from the lamination assembly to the cooling fluid flowing in the cooling channel. Additionally, the insertion of the sleeve into the opening of the rotor lamination assembly reliably prevents rotation of the rotor laminations relative to each other about the rotor's axis of rotation. Therefore, it is possible to define the cross-section of the cooling channel along its entire length extending in the axial direction by a sleeve and / or tension anchors. The sleeve effectively prevents the undesirable narrowing of the cooling channel's cross-section due to the relative rotation of adjacent rotor laminations about the axis of rotation in the stacking direction.

[0007] In one extended embodiment of the invention, the rotor is specified to have a hollow rotor shaft on which the rotor laminations are torsionally supported. Furthermore, the rotor includes two tension plates, each disposed on an end side of the rotor laminations. This means that the two tension plates abut against the opposing end sides of the rotor laminations. Therefore, the rotor laminations are positioned axially between the two tension plates. The two tension plates are secured to their respective end sides of the rotor laminations by means of at least one tension anchor. At least one tension plate has at least one cooling fluid supply channel through which cooling fluid discharged from the hollow rotor shaft via an opening in the rotor shaft can be guided radially. Specifically, the tension anchor is inserted through a corresponding tension opening of each tension plate and grips the wall defining the corresponding tension opening of each tension plate from behind. This means that the tension anchor abuts against the corresponding outer side of each tension plate opposite to the rotor laminations, inserts through the tension opening of each tension plate, and extends through the opening of the rotor laminations. Because the tension anchors grip the tension openings of each tensioning plate from the outside and from behind, each tensioning plate is pressed from the outside onto the rotor lamination assembly, particularly onto the corresponding end sides, with each tensioning plate abutting against said end sides. Specifically, it is stipulated that the sleeve does not extend through the tension openings of each tensioning plate, but only through the openings of the rotor lamination assembly. The at least one cooling fluid supply channel in the at least one tensioning plate extends at least partially in the radial direction, thus allowing cooling fluid flowing radially from the rotor shaft opening via the rotor shaft to be guided to the cooling channel by means of the cooling fluid supply channel. Therefore, each tensioning plate, on the one hand, allows the corresponding end faces of the rotor lamination assembly to be loaded with a particularly uniform force acting in the axial direction, and thus allows for particularly uniform mutual pressing of the rotor laminations of the rotor lamination assembly, and further allows for reliable guidance of cooling fluid from the hollow rotor shaft to the at least one cooling channel.

[0008] In this relationship, it can be specifically stipulated that at least one of the tensioning plates has a cooling fluid outlet channel, through which cooling fluid discharged from the cooling channel can be radially outwardly drawn from the cooling channel. Thus, the cooling fluid outlet channel is used to draw cooling fluid out of the cooling channel after it has flowed through it. For example, the cooling fluid outlet channel can be configured to throw the cooling fluid received from the cooling channel toward the stator of the motor during operation, so that the stator can be cooled by means of the cooling fluid after the rotor laminations have been cooled. Therefore, the motor can be cooled particularly effectively by means of the cooling fluid. Thus, each tensioning plate allows for reliable guidance of cooling fluid from the hollow rotor shaft to the cooling channel and reliable guidance of cooling fluid away from the cooling channel via the at least one cooling fluid outlet channel, especially reliable guidance from the rotor shaft.

[0009] In another possible embodiment of the invention, the rotor has an annular channel extending around the tension anchor in the circumferential direction and fluidly connected to the cooling channel. Therefore, cooling fluid to be supplied to the cooling channel can be collected before supplying to the cooling channel, or cooling fluid discharged from the cooling channel can be collected before being drawn out of the cooling channel. The annular channel can be provided, in particular, through a notch in the tension anchor surrounding its circumference. In this case, the annular channel is defined at least partially by the notch in the tension anchor and partially by one of the tension plates. Depending on whether the annular channel is upstream or downstream of the cooling channel, it is configured to collect cooling fluid to be supplied to the cooling channel before supplying, or to collect cooling fluid flowing out of the cooling channel after flowing out. Therefore, the annular channel allows for reliable and particularly low-leakage supply of cooling fluid to or from the cooling channel at the transition between the cooling channel and the cooling fluid outlet channel, or at the transition between the cooling channel and the cooling fluid supply channel.

[0010] In another possible embodiment of the invention, the sleeve and the opening in the rotor lamination assembly have corresponding cross-sections, the corresponding shapes of which differ from those of annulus and circle. For example, the sleeve and the opening may have a trapezoidal or triangular shape with rounded corners, or a fan shape, around their outer circumferences. This corresponding construction of the sleeve's cross-section and the opening's cross-section ensures a reliable fit of the sleeve's entire outer circumference against the wall defining the opening in the rotor lamination assembly. If the sleeve has a cross-section different from an annulus shape and the opening has a cross-section different from a circle, the sleeve is locked in the opening to prevent rotation about the axial direction. The risk of the sleeve rotating about the axial direction in the opening is therefore particularly small. Furthermore, the cross-sections of the opening and the sleeve can be selected according to the predetermined cross-section to be achieved for the cooling channel. In other words, the cross-sections of the sleeve and the opening can be selected according to the cooling requirements to be achieved for the cooling channel. Therefore, particularly effective cooling of the rotor lamination assembly can be achieved by means of the cooling fluid flowing through the cooling channel.

[0011] In another possible embodiment of the invention, the tension anchor has a centering section in at least one length region along the axial direction, in which the tension anchor abuts against the inner side of the sleeve at multiple locations. Because the tension anchor abuts against the inner side of the sleeve at these multiple locations, the relative position between the tension anchor and the sleeve is precisely defined. Therefore, it can be ensured that the cooling channel defined by the tension anchor and / or the sleeve precisely has a predetermined cross-section.

[0012] In this relationship, it can be specifically stipulated that the tension anchor has a plurality of axially extending ribs in the centering section, the ribs being distributed circumferentially around the tension anchor in the centering section, and the ribs abutting against the inner side of the sleeve. The plurality of axially extending ribs allows, on the one hand, the tension anchor to be constructed with particularly low weight in the centering section, because the tension anchor does not abut against the inner side of the sleeve over its entire circumference, but only against the inner side of the sleeve via the ribs. Furthermore, as long as the ribs extend axially in their longitudinal direction, the ribs can open in the corresponding area between the inner side of the sleeve and the tension anchor, allowing cooling fluid to flow axially between the sleeve and the tension anchor in the same area. In other words, the tension anchor has corresponding recesses between adjacent ribs in the circumferential direction of the tension anchor, the recesses extending across the entire axial length of the centering section and allowing cooling fluid to flow through them. Therefore, it is permissible for the tension anchor to be centered relative to the sleeve in the centering section by direct contact with the sleeve, and simultaneously, due to the recesses between the corresponding ribs, the cooling fluid can flow in the axial direction through the centering section of the tension anchor in the axial direction, or in other words, in the axial direction, in such a way that the cooling fluid flows through the corresponding recesses of the tension anchor between the adjacent ribs in the circumferential direction.

[0013] In another possible embodiment of the invention, the tension anchor may have a surrounding flange in the centering section, the flange abutting against the inner side of the sleeve. Additionally, the flange has at least one through-hole extending in the axial direction, through which cooling fluid can flow to or from the at least one cooling channel. In particular, fluid connection between the cooling channel and a cooling fluid supply or outlet channel is provided via the at least one through-hole extending in the longitudinal direction. Therefore, reliable and precise centering of the tension anchor relative to the sleeve is allowed via the centering section, and further, it is ensured that cooling fluid can flow into or out of the cooling channel.

[0014] The present invention also relates to a motor vehicle including a traction motor. The traction motor is configured to drive the motor vehicle by means of electrical energy. The traction motor includes a stator and a rotor rotatable relative to the stator about a rotational axis, as already described in the section on the rotor of the present invention. Because the rotor has cooling channels extending axially through the rotor laminations, the rotor laminations can be cooled particularly effectively by means of cooling fluid through the cooling channels, thus enabling the traction motor to operate particularly efficiently. Therefore, the motor vehicle can also be driven particularly efficiently by means of the traction motor.

[0015] The present invention also relates to a method for manufacturing a rotor, as described in relation to the rotor according to the invention. In this method, a sleeve is inserted with a gap in the axial direction into an associated opening of a rotor lamination assembly. A tension anchor is then inserted through the sleeve in the axial direction. The rotor lamination assembly is then tensioned by means of the tension anchor, wherein the sleeve is axially pressure-loaded by the tension anchor, thus pressing its outer wall against the wall defining the opening of the rotor lamination assembly, and thus against the rotor lamination assembly. The rotor lamination assembly may have multiple openings, which may be distributed, particularly around the axis of rotation of the rotor, on the rotor laminations. Specifically, it is specified that one sleeve and one tension anchor are inserted into each of these openings in the rotor lamination assembly. Therefore, multiple cooling channels extending in the axial direction can be provided in the rotor lamination assembly. Furthermore, the multiple tension anchors allow for particularly reliable and uniform compression of the rotor laminations in the rotor lamination assembly. When the sleeve is inserted into the corresponding opening of the rotor lamination assembly, there is a radial clearance between the sleeve and the opening. Therefore, the sleeve can be inserted into the corresponding opening of the rotor lamination assembly particularly easily in the axial direction. The clamping of the sleeve in the corresponding opening is achieved by tension anchors, which simultaneously press the rotor laminations together in the axial direction and apply forces to their respective axial ends along the axial direction, compressing the sleeve in the axial direction. Thus, the sleeve abuts against the wall of the rotor lamination assembly defining the opening on its outer circumferential side, thereby achieving particularly good heat transfer from the rotor lamination assembly to the sleeve. Therefore, particularly efficient heat dissipation can be achieved from the rotor lamination assembly through the sleeve to the cooling fluid flowing through the cooling channels.

[0016] Other features of the invention can be obtained from the claims, the drawings, and the description taken in conjunction with the drawings. Features and combinations of features mentioned above in the specification, as well as features and combinations of features shown separately in the description taken in conjunction with the drawings and / or in the drawings, may be applied not only in the correspondingly described combinations, but also in other combinations, or may be applied separately, without departing from the scope of the invention. Attached Figure Description

[0017] The attached figure is the only one ( Figure 1 The diagram shows a partial schematic cross-sectional view of the rotor of a traction motor used in motor vehicles. Detailed Implementation

[0018] exist Figure 1The image shows a rotor 10 for a traction motor used in a motor vehicle. The rotor 10 currently includes a rotor shaft 12 and a rotor lamination assembly 14 torsionally supported on the rotor shaft 12. The rotor 10 is rotatable during operation about a rotation axis 16 extending in an axial direction A. The rotor lamination assembly 14 includes a plurality of rotor laminations stacked on top of each other in the axial direction A. The rotor 10 currently also includes two tension plates 18 disposed on opposing end sides 20 of the rotor laminations 14. In the current specification, each tension plate 18 is also torsionally supported on the rotor shaft 12. The rotor lamination assembly 14 currently has a plurality of openings 22 extending in the axial direction A. In each of these openings 22, a sleeve 24 is inserted in the axial direction A. The corresponding sleeve 24 is currently hollow cylindrical. In the current specification, the sleeve 24 is configured as a tube made of aluminum with a diameter of 10 mm.

[0019] The rotor 10 currently has multiple tension anchors 26. Currently, one tension anchor 26 is inserted into each sleeve 24 in the axial direction A, specifically through the correspondingly associated sleeve 24. Currently, each tension anchor 26 includes a tension bolt 28 and a nut 30. The nut 30 is screwed onto the free end of the tension bolt 28. The tension anchor 26 is inserted through a corresponding tension opening 32 of each tensioning plate 18, thus the bolt head 34 of the tension bolt 28 is positioned on the outer side of the associated tensioning plate 18 opposite to the rotor lamination assembly 14. Additionally, the nut 30 assigned to this tension bolt 28 is positioned on the outer side of another tension bolt 18 in the axial direction A, opposite to the rotor lamination assembly 14. If the nut 30 is now further tightened onto the free end of the tension bolt 28, the tension plates 18 are pressed against each other in the axial direction by means of the bolt head 34 and the nut 30, thus pressing the rotor lamination assembly 14 disposed between the tension plates 18 in the axial direction A. Therefore, each tension anchor 26 allows the rotor laminations of the rotor lamination assembly 14 to be pressed together in the axial direction A by the tension plates 18. Each tension plate 18 allows the force applied by the tension anchor 26 in the axial direction A to be distributed over a particularly large area and therefore evenly across each end side 20 of the rotor lamination assembly 14. Instead of the corresponding tension anchor 26 having the construction of bolt 28 and nut 30, each tension anchor 26 may have a threaded rod, on which a nut 30 is screwed. Currently, the tension bolt 28 and nut 30 each have M5 threads.

[0020] To allow for particularly effective cooling of the rotor lamination assembly 14, cooling fluid is provided in the corresponding openings 22 of the rotor lamination assembly 14. For this purpose, corresponding tension anchors 26, together with correspondingly associated sleeves 24, define cooling channels 36 extending in the axial direction A. These cooling channels 36, extending in the corresponding openings 22, extend through the rotor lamination assembly 14 in the axial direction A and are configured for the flow of cooled fluid. Currently, the corresponding cooling channels 36 are defined on the outer circumferential side by the sleeves 24. Since the tension anchors 26 extend through the correspondingly associated sleeves 24 in the axial direction A, the corresponding cooling channels 36 have an annular cross-section at least along the axial direction A in one length region. Therefore, cooling fluid is guided along the inner side of the corresponding sleeves 24 in these cooling channels 36, thus each sleeve 24 can be cooled particularly effectively by means of the cooling fluid. Since the corresponding sleeves 24 are made of aluminum, particularly effective heat dissipation of the rotor lamination assembly 14 is achieved via each sleeve 24. Each sleeve 24 rests its outer surface against the wall of the corresponding associated opening 22 of the rotor lamination assembly 14 around its entire circumference.

[0021] The cooling fluid flows along the axial direction A in a predetermined flow direction within the respective cooling channels 36. The cooling fluid flows in a first flow direction 38 in at least one of the cooling channels 36 and in a second flow direction 40, opposite to the axial direction A and the first flow direction 38, in at least one of the second cooling channels 36. By utilizing the opposite flow directions 38 and 40 of the cooling fluid in the different cooling channels 36, particularly uniform cooling of the rotor lamination assembly 14 can be achieved by means of the cooling fluid flowing through each cooling channel 36.

[0022] In particular, the cooling channels 36 that are arranged directly adjacent to each other in the circumferential direction around the rotation axis 16 of the rotor 10 can each have different flow directions 38 and 40.

[0023] In the current configuration, cooling fluid is guided within a hollow rotor shaft 12. The hollow rotor shaft 12 currently has multiple rotor shaft openings 42 configured as radial holes, through which cooling fluid flowing within the hollow rotor shaft 12 can exit. To guide the cooling fluid exiting the rotor shaft 12 via the rotor shaft openings 42 to corresponding cooling channels 36, one of the tension plates 18 is provided with a cooling fluid supply channel 44 for each of the cooling channels 36. This cooling fluid supply channel 44 is fluidly connected at one end to the corresponding rotor shaft opening 42 of the rotor shaft 12 and at the other end to the corresponding cooling channel 36. Additionally, a cooling fluid outlet channel 46 is provided for each cooling channel 36, provided by one of the tension plates 18. The cooling fluid outlet channel 46 currently extends in the radial direction R along its longitudinal extension direction. The cooling fluid supply channel 44 currently extends in the radial direction R along its longitudinal extension direction. The radial direction R is perpendicular to the axial direction A. The cooling fluid outlet channel 46 is fluidly connected at one end to the associated cooling channel 36 and terminates at the other end in the environment of the rotor 10. Therefore, cooling fluid flowing from the associated cooling channel 36 can be drawn out from the cooling channel 36 and, in particular, guided into the environment of the rotor 10, especially thrown into the environment, via the cooling fluid outlet channel 46. Specifically, the cooling fluid flowing out from the cooling fluid outlet channel 46 can be thrown onto the stator of the traction motor having the rotor 10 due to the centrifugal force acting on it. Therefore, by means of the cooling fluid, after cooling the rotor 10, the stator can be additionally, at least partially, cooled.

[0024] To allow for a reliable fluid transition from the cooling fluid supply channel 44 to the associated cooling channel 36 and from the cooling channel 36 to the associated cooling fluid outlet channel 46, two annular channels 48 are provided for each cooling channel 36. The respective annular channels 48 extend circumferentially around the circumference of the tension anchor 26 assigned to that cooling channel 36. In this case, the respective annular channels 48 are located in the end regions of the tension anchor 26 that are opposite each other in the axial direction A. (As in...) Figure 1As can be seen, the corresponding annular channels 48 are defined in terms of their inner radius by the associated tension anchors 26 and in terms of their outer radius by one of the tension plates 18. Currently, each of the annular channels 48 is disposed in a corresponding tension plate among the respective tension plates 18. The profile of the corresponding annular channel 48 can be defined by a notch that surrounds the tension anchor 26 circumferentially. The corresponding cooling fluid supply channels 48 lead into one of the annular channels 48 respectively, so that the cooling fluid flowing out from the cooling fluid supply channels 44 can be collected in these annular channels 48 and guided to the associated cooling channels 36. The cooling fluid flowing out from the corresponding cooling channels 36 can be collected in the corresponding annular channels 48 disposed downstream of the cooling channels 36, and a cooling fluid outlet channel 46 can be provided for the corresponding cooling fluid outlet channel 46. The corresponding annular channel 48 ensures fluid connection between the cooling channel 36 and the correspondingly associated cooling fluid supply channel 44 and cooling fluid outlet channel 46, regardless of the rotational position of the tension anchor 26 about the longitudinal extension direction extending in the axial direction A of the tension anchor.

[0025] To ensure precise orientation of the tension anchor 26 relative to the sleeve 24, the tension anchor 26 has at least one centering section 50. Currently, the tension anchor 26 has two centering sections 50. Here, the first centering section 50 is located in the region of the first end of the cooling channel 36, and the second centering section 50 is located in the region of the second end of the cooling channel 36 opposite to the first end in the axial direction A. In each corresponding centering section 50, the tension anchor 26 abuts against the inner side of the sleeve 24 at multiple locations on its circumference. Therefore, the tension anchor 26 is precisely centered relative to the sleeve 24. The tension anchor 26 may have multiple ribs extending in the axial direction in each corresponding centering section 50, via which the tension anchor 26 abuts against the inner side of the sleeve 24. These ribs may be evenly distributed on the circumference of the tension anchor 26 in the corresponding centering sections 50. However, in the current specification, the tension anchor 26 has a surrounding flange 52 in each of the centering sections 50, the tension anchor 26 abutting against the inner side of the sleeve 24 via the flange. This flange 52 is currently traversed by at least one through-hole 54 extending in the axial direction A, through which cooling fluid can flow. Through this through-hole 54, cooling fluid can flow from an annular channel 48 located upstream of the cooling channel 36 into the cooling channel 36, or from the cooling channel 36 into an annular channel 48 located downstream of the cooling channel 36. In the current specification, the nut 30 of the corresponding tension anchor 26 is correspondingly provided with a surrounding flange 52 having the through-hole 54 at one end of the tension anchor 26. The surrounding flange 52 at the other end of the tension anchor 26 is currently provided by a tensioning bolt 28.

[0026] It is possible that the sleeve 24 and the opening 22 in the rotor lamination group 14 have corresponding cross sections, the shape of which is different from that of an annulus and a circle, and the cross sections of the sleeve 24 and the opening 22 correspond to each other.

[0027] The invention described is based on the understanding that during the cooling of the tension anchor 26 of the rotor 10, a heat transfer problem can occur from the tension anchor 26 to the rotor lamination assembly 14. This can be solved by dimensional coverage between the tension anchor 26 and the rotor lamination assembly 14. Dimensional coverage can be understood as the margin of the tension anchor 26 relative to the opening 22 of the rotor lamination assembly 14. However, this coverage can lead to increased costs during the installation of the rotor 10. Additionally, this coverage decreases when the tension anchor 26 is tensioned by lateral reduction, which may result in even worse heat transfer between the tension anchor 26 and the rotor lamination assembly 14. To overcome these drawbacks, in conjunction with... Figure 1 In the case of rotor 10 described in the relational specification, rotor 10 has sleeves 24 that are inserted into corresponding openings 22 of rotor lamination 14, and corresponding corresponding tension anchors 26 are inserted through said sleeves. When the corresponding tension bolts 28 of the tension anchors 26 are tightened, the outer diameter of the corresponding sleeves 24 increases because the sleeves 24 are subjected to pressure in the axial direction A by means of the tension anchors 26. By increasing the outer diameter of the corresponding sleeves 24, particularly good heat transfer between rotor lamination 14 and the corresponding sleeves 24 can be achieved. Because the increase in the outer diameter of the sleeves 24 is only achieved when the tension anchors 26 are tightened, the corresponding sleeves 24 can be inserted into the corresponding corresponding openings 22 of rotor lamination 14 in the axial direction A without margin and especially with clearance. Therefore, rotor 10 can be installed particularly easily.

[0028] List of reference numerals

[0029] 10 rotors

[0030] 12 Rotor Shaft

[0031] 14 Rotor lamination assembly

[0032] 16 Rotation axis

[0033] 18 tensioning plates

[0034] 20 end side

[0035] 22 Opening

[0036] 24 sleeve

[0037] 26 Tension anchors

[0038] 28 tension bolts

[0039] 30 nuts

[0040] 32 tension openings

[0041] 34 Bolt head

[0042] 36 Cooling Channels

[0043] 38 First flow direction

[0044] 40 Second flow direction

[0045] 42 Rotor shaft opening

[0046] 44 Cooling fluid supply channel

[0047] 46 Cooling fluid outlet channel

[0048] 48 Circular Channel

[0049] 50-point centering section

[0050] 52 Flange

[0051] 54 Through Hole

[0052] Axial direction

[0053] R radial direction

Claims

1. A rotor (10) for an electric motor, the rotor being configured to rotate in operation about a rotation axis (16) extending in an axial direction (A), the rotor comprising: The rotor lamination assembly (14) includes a plurality of rotor laminations that abut against each other in the axial direction (A); at least one sleeve (24) that extends in the axial direction (A) through an opening (22) of the rotor lamination assembly (14) and abuts against the wall of the rotor lamination assembly (14) defining the opening (22) on the circumferential side with its outer wall; At least one tension anchor (26) is inserted through a sleeve (24) in the axial direction (A) and tensions the rotor laminations together in the axial direction (A), wherein the tension anchor (26) together with the sleeve (24) defines at least one cooling channel (36) extending within the sleeve (24) in the axial direction (A) through the rotor lamination assembly (14) and the cooling channel is permeable to cooling fluid.

2. The rotor (10) according to claim 1, characterized in that, The rotor (10) has a hollow rotor shaft (12), the rotor lamination assembly (14) is torsionally supported on the rotor shaft, and the rotor includes two tension plates (18), which are respectively disposed on the end side of the rotor lamination assembly (14) and pressed onto the corresponding end side (20) of the rotor lamination assembly (14) by means of tension anchors (26). At least one of the tension plates (18) has at least one cooling fluid supply channel (44), through which cooling fluid discharged from the hollow rotor shaft (12) via the rotor shaft opening (42) can be guided in the radial direction (R) to the at least one cooling channel (36).

3. The rotor (10) according to claim 2, characterized in that, At least one of the tensioning plates (18) has a cooling fluid outlet channel (46) through which cooling fluid discharged from the cooling channel (36) can be radially outward from the cooling channel (36) via the cooling fluid outlet channel.

4. The rotor (10) according to any one of the preceding claims, characterized in that, An annular channel (48) is provided, which extends around the tension anchor (26) in the circumferential direction and is fluidly connected to the cooling channel (36), so that the cooling fluid to be supplied to the cooling channel (36) can be collected before being supplied to the cooling channel (36), or so that the cooling fluid discharged from the cooling channel (36) can be collected before being drawn out from the cooling channel (36).

5. The rotor (10) according to any one of the preceding claims, characterized in that, The sleeve (24) and the opening (22) in the rotor lamination group (14) have corresponding cross sections, the corresponding shapes of which are different from those of annulus and circle.

6. The rotor (10) according to any one of the preceding claims, characterized in that, The tension anchor (26) has a centering section (50) in at least one length region along the axial direction (A), and the tension anchor (26) abuts against the inside of the sleeve (24) at multiple locations in the centering section.

7. The rotor (10) according to claim 6, characterized in that, The tension anchor (26) has multiple axially extending ribs in the centering section (50), the ribs being distributed around the circumference of the tension anchor (26) in the centering section (50), and the ribs abutting against the inner side of the sleeve (24).

8. The rotor (10) according to claim 6 or 7, characterized in that, The tension anchor (26) has a surrounding flange (52) in the centering section (50), the flange abutting against the inside of the sleeve (24), and the flange has at least one through hole (54) extending in the axial direction (A), through which cooling fluid can flow to or out of the at least one cooling channel (36).

9. A motor vehicle comprising a traction motor, the traction motor comprising a stator and a rotor (10) rotatable relative to the stator about a rotation axis according to any of the preceding claims.

10. A method for manufacturing a rotor (10) according to any one of claims 1 to 8, wherein a sleeve (24) is inserted with a gap in the axial direction (A) into a corresponding opening (22) of a rotor lamination assembly (14), a tension anchor (26) is inserted through the sleeve (24) in the axial direction (A), and the rotor lamination assembly (14) is tensioned by means of the tension anchor (26), wherein, By means of tension anchor bolts (26), the sleeve (24) is loaded with pressure in the axial direction, so that the sleeve (24) is pressed against the wall of the rotor lamination assembly (14) defining the opening (22) with its outer wall and thus pressed against the rotor lamination assembly (14).

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