Rotor of an electric machine
Patent Information
- Application Number
- EP2023790328
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-11-09
- Filing Date
- 2023-10-17
- Publication Date
- 2025-09-17
AI Technical Summary
High pressures during rotation in the cooling path of a rotor in electrical machines cause mechanical stress on end disks, leading to potential leaks and increased mechanical load, which existing designs struggle to manage effectively.
The rotor sleeve applies an additional axial holding force to the end disk, with a tapered support surface on the end disk reducing pressure and eliminating the need for an adhesive connection, while a sealing structure ensures a tight connection between the sleeve and disk, enhancing sealing and reducing leakage.
This configuration increases the resilience of the press connection, minimizes leakage, and maintains effective cooling, allowing for efficient operation with reduced mechanical stress and improved sealing.
Smart Images
Figure 1.1
Abstract
Description
[0001] Description
[0002] title
[0003] Rotor of an electrical machine
[0004] State of the art
[0005] The invention is based on a rotor of an electrical machine according to the preamble of the main claim.
[0006] A rotor of an electrical machine, in particular a permanent magnet synchronous machine, is already known from DE102017129212 A1, having a rotor shaft rotatable about a rotor axis, having a rotor body arranged on the rotor shaft, which is designed in particular as a rotor laminated core, and having at least one end plate arranged on one of the two end faces of the rotor body, wherein the rotor body is enclosed by at least one rotor sleeve, in particular a fiber composite sleeve, wherein the rotor sleeve extends beyond the rotor body in the axial direction with respect to the rotor axis with a sleeve end section and rests with the sleeve end section under prestress against an annular bearing surface of the respective end plate, wherein a cooling path is formed in the rotor body, which cooling path is fluidly connected to a shaft cooling channel of the rotor shaft for cooling the rotor with a cooling fluid.
[0007] A disadvantage is that very high pressures arise in the cooling path during the rotation of the rotor, which act on the respective end plate in an axial direction away from the rotor body, placing significant mechanical stress on it. This can cause or exacerbate a leak between the rotor body and the end plate.
[0008] Advantages of the invention
[0009] The rotor of an electric machine according to the invention with the characterizing features of the main claim has the advantage that the rotor sleeve exerts an additional axial holding force on the respective end plate, so that the press connection between the rotor sleeve end section and the end plate can absorb higher axial compressive forces and thus has a higher load-bearing capacity. Furthermore, the axial pressing of the end plate against the rotor body reduces leakage gaps between the rotor body and the end plate, so that the press connection between the rotor sleeve end section and the end plate is subjected to less pressure. An adhesive connection between the rotor sleeve end section and the end plate can be dispensed with.
[0010] This is achieved according to the invention in that the support surface of the respective end plate tapers towards a side of the end plate facing away from the rotor body in the radial direction with respect to the rotor axis, in particular in a conical manner.
[0011] The measures listed in the subclaims enable advantageous further developments and improvements of the rotor of an electrical machine specified in the main claim.
[0012] It is particularly advantageous if the contact surface of the respective end plate is flush with the outer circumference of the rotor body at an end facing the rotor body. This achieves a seamless transition from the rotor core to the respective end plate, so that the rotor sleeve rests flatly and / or continuously against both the rotor core and the respective end plate.
[0013] It is very advantageous if a seal is provided between the contact surface of the respective end plate and the rotor sleeve, in particular a sealing structure on the contact surface or a separate sealing element between the contact surface of the respective end plate and the rotor sleeve. This creates a tight or quasi-tight connection between the contact surface of the respective end plate and the rotor sleeve, so that the cooling path formed in the rotor is particularly well sealed and little or no unintentional leakage from the cooling path occurs.
[0014] It is also advantageous if the respective end plate is a plastic plate, a composite plate or a metal plate.
[0015] In the case of a plastic disc, according to a first embodiment, channel sections of a cooling path for cooling the rotor can be cost-effectively integrated into the end disc. Furthermore, the plastic disc can insulate a ferromagnetic metal disc mounted on the plastic disc from the rotor body, so that the magnetic circuit in the rotor is not negatively affected. The plastic disc can be a separate element or, for example, molded onto the rotor body.
[0016] It is very advantageous if the composite disc comprises a plastic and a filler, particularly made of metal or a mineral, embedded in the plastic. In this way, the composite disc can form a balancing disc for subtractive balancing.
[0017] According to the first embodiment, the rotor sleeve can be a fiber composite sleeve wound directly onto the rotor with pretension, with a winding start or winding end of the fiber composite sleeve provided on the support surface of the respective end plate. In this way, the winding tensile force during winding of the fiber composite sleeve is divided into a radial and an axial component, which presses the end plate against the rotor body and thereby creates a high degree of tightness in the cooling path.
[0018] It is also advantageous if the support surface of the respective end plate according to the first embodiment is delimited at an end facing away from the rotor body by an annular collar that protrudes radially relative to the rotor axis relative to the support surface. In this way, the end of the support surface is clearly defined, so that the winding start or end for a fiber composite sleeve wound directly onto the rotor is more clearly defined.
[0019] It is also advantageous if a material-to-material bond is formed between the plastic of the rotor sleeve and the plastic of the respective composite or plastic disc. This makes it easy to create a tight connection between the rotor sleeve and the end disc.
[0020] Furthermore, it is advantageous if the rotor sleeve according to an alternative embodiment is a prefabricated fiber composite sleeve which is pushed or pressed onto the rotor in the axial direction and is prestressed in the assembled state.
[0021] It is also advantageous to provide two rotor sleeves that are pushed or pressed onto the rotor from different ends. The two rotor sleeves or rotor sleeve halves can be made thinner than a single rotor sleeve that is twice as long, because the pressing forces for a rotor sleeve increase linearly with the pressing length and are thus halved.
[0022] If the two rotor sleeve halves are pressed on at the same time, the assembly time for pressing the rotor sleeve halves on is shorter than with a single, double-length rotor sleeve.
[0023] It may also be advantageous if at least one connecting channel is formed in the respective end plate as part of the cooling path, which is fluidly connected radially inwardly via a shaft outlet to the shaft cooling channel and radially outwardly to cooling channels of the rotor body. This allows the cooling channels of the rotor body to be fluidly connected to the shaft cooling channel in a simple manner, thus achieving effective and efficient rotor cooling.
[0024] It is further advantageous if a disk holder for receiving a metallic balancing disk is formed on an end face of the respective end disk facing away from the rotor body, wherein the balancing disk arranged in the disk holder is pressed onto the rotor shaft with an inner circumference. In this way, the respective end disk is supported by the balancing disk in a radially inner region. This creates high rigidity and strength in the radially inner region of the end disk, enabling a high pressing force in the radially outer region on the bearing surface of the end disk.
[0025] The invention further relates to an electrical machine with a rotor according to the invention.
[0026] drawing
[0027] Embodiments of the invention are shown in simplified form in the drawing and explained in more detail in the following description.
[0028] They show:
[0029] Fig.l shows in section a rotor according to the invention of an electrical machine, Fig.2 shows a view of a detail A according to Fig.l according to a first
[0030] Embodiment, Fig.3 a view of the detail A according to Fig.l according to a second embodiment,
[0031] Fig.4 is a view of detail A of Fig.l according to a third embodiment and
[0032] Fig.5 a view of a detail B according to Fig.l.
[0033] Description of the embodiments
[0034] Fig.l shows a section through a rotor of an electrical machine according to the invention.
[0035] The rotor 1 according to the invention of an electrical machine 2, in particular a permanent magnet synchronous machine, comprises a rotor shaft 4 rotatable about a rotor axis 3, a rotor body 5 arranged on the rotor shaft 4, which is designed in particular as a rotor laminated core, and at least one end plate 6 arranged on one of the two end faces of the rotor body 5. The respective end plate 6 rests on the rotor body 5.
[0036] The rotor body 5 is enclosed by at least one prestressed rotor sleeve 7, in particular a fiber composite sleeve. The rotor sleeve 7 extends beyond the rotor body 5 in the axial direction with respect to the rotor axis 3 with a sleeve end section 7e, and rests with the prestressed sleeve end section 7e against an annular support surface 10 on the outer circumference of the respective end plate 6. A cooling path 8 is formed in the rotor body 5, which is fluidly connected to a shaft cooling channel 14 of the rotor shaft 4 for cooling the rotor 1 with a cooling fluid, in particular oil.
[0037] In the respective end plate 6, at least one connecting channel 15 is formed as part of the cooling path 8, which is fluidly connected radially inwardly via a shaft outlet 16 to the shaft cooling channel 14 and radially outwardly to in particular axial cooling channels 17 of the rotor body 5.
[0038] On an end face of the respective end plate 6 facing away from the rotor body 5, a balancing disc receptacle 20 can be formed, for example, in which a metallic balancing disc 21 is arranged for axially supporting the end plate 6. The balancing disc receptacle 20 of the end plate 6 has, for example, at least one centering shoulder 22, which is designed for the radial alignment of the end plate 6 relative to the outer circumference of the balancing disc 21 and forms the balancing disc receptacle 20.
[0039] The balancing disc 21 rests against the end disc 6, for example, with a contact surface, for axial support of the end disc 6. The balancing disc 21 is attached, in particular pressed, to the rotor shaft 4 for axial support of the end disc 6.
[0040] Fig.2 shows a view of a detail A according to Fig.1 according to a first embodiment.
[0041] According to the invention, it is provided that the support surface 10 of the respective end plate 6 tapers towards a side of the end plate 6 facing away from the rotor body 5 in the radial direction with respect to the rotor axis 3 at an angle a, in particular extends conically.
[0042] The support surface 10 of the respective end plate 6 is designed to be flush with the outer circumference of the rotor body 5 at an end facing the rotor body 5.
[0043] The respective end disc 6 can be a plastic disc, a composite disc, or a metal disc. A composite disc is understood to be a disc that comprises a plastic and a filler embedded in the plastic, in particular a metal or mineral.
[0044] The rotor sleeve 7 can, for example, be a fiber composite sleeve wound directly onto the rotor 1 with prestress, with a winding start or winding end of the fiber composite sleeve provided on the support surface 10 of the respective end plate 6. The fiber composite sleeve comprises a fiber winding, in particular made of glass fiber or carbon fiber, and a cured composite material for embedding the fiber winding.
[0045] The support surface 10 of the respective end plate 6 can be delimited at an end facing away from the rotor body 5 by an annular collar 11, which protrudes radially relative to the rotor axis 3 relative to the support surface 10. A material-to-material joint can be provided between a plastic of the rotor sleeve 7 and the plastic of the respective composite or plastic plate 6 to seal the connection.
[0046] Alternatively, the rotor sleeve 7 can be a prefabricated fiber composite sleeve that is pushed or pressed onto the rotor 1 in the axial direction relative to the rotor axis 3 and preloaded in the assembled state. The rotor sleeve 7 to be pushed on can have two radial layers, whereby the outer of the two radial layers can, for example, be reinforced for axial pushing or pressing.
[0047] Fig. 3 shows a view of detail A of Fig. 1 according to a second embodiment. Fig. 4 shows a view of detail A of Fig. 1 according to a third embodiment.
[0048] A seal can be provided between the support surface 10 of the respective end plate 6 and the rotor sleeve 7, for example a separate sealing element 12 between the support surface 10 of the respective end plate 6 and the rotor sleeve 7 according to Fig.3 or for example a particularly groove-shaped sealing structure 13 on the support surface 10 according to Fig.4.
[0049] Fig.5 shows a view of a detail B according to Fig.l.
[0050] In the case of an axially slidable rotor sleeve 7, it may be expedient to construct the rotor sleeve 7 in two pieces and to slide the two rotor sleeves or rotor sleeve halves 7.1, 7.2 onto the rotor 1 from different end faces. After assembly, the two rotor sleeves 7.1, 7.2 each rest with their prestressed sleeve end section 7e against the annular support surface 10 of the respective end plate 6.
Claims
Claims 1. Rotor (1) of an electrical machine (2), in particular a permanent magnet synchronous machine, with a rotor shaft (4) rotatable about a rotor axis (3), with a rotor body (5) arranged on the rotor shaft (4), which is designed in particular as a rotor laminated core, and with at least one end plate (6) arranged on one of the two end faces of the rotor body (5), wherein the rotor body (5) is enclosed by at least one rotor sleeve (7), in particular a fiber composite sleeve, wherein the rotor sleeve (7) extends beyond the rotor body (5) in the axial direction with respect to the rotor axis (3) with a sleeve end section (7e) and rests with the sleeve end section (7e) under prestress against an annular bearing surface (10) of the respective end plate (6), wherein a cooling path (8) is formed in the rotor body (5), which cooling path is connected to a shaft cooling channel (14) of the rotor shaft (4) is fluidly connected to cool the rotor (1) with a cooling fluid, characterized in that the support surface (10) of the respective end plate (6) extends to a rotor body (5) facing away from the end plate (6) in the radial direction with respect to the rotor axis (3), in particular it is conical.
2. Rotor according to claim 1, characterized in that the support surface (10) of the respective end plate (6) is designed to be flush with the outer circumference of the rotor body (5) at an end facing the rotor body (5).
3. Rotor according to one of the preceding claims, characterized in that a seal is provided between the support surface (10) of the respective end plate (6) and the rotor sleeve (7), in particular a sealing structure (13) on the support surface (10) or a separate sealing element (12) between the support surface (10) of the respective end plate (6) and the rotor sleeve (7).
4. Rotor according to one of the preceding claims, characterized in that the respective end disc (6) is a plastic disc, a composite disc or a metal disc.
5. Rotor according to claim 4, characterized in that the composite disc (6) comprises a plastic and a filler embedded in the plastic, in particular made of metal or a mineral.
6. Rotor according to one of the preceding claims, characterized in that the rotor sleeve (7) is a fiber composite sleeve wound with pretension directly onto the rotor (1), wherein a winding start or a winding end of the fiber composite sleeve (7) is provided on the support surface (10) of the respective end plate (6).
7. Rotor according to claim 6, characterized in that the support surface (10) of the respective end plate (6) is delimited at an end facing away from the rotor body (5) by an annular collar (11) which projects in the radial direction with respect to the rotor axis (3) relative to the support surface (10).
8. Rotor according to one of claims 6 or 7, characterized in that a material-locking joint is formed between a plastic of the rotor sleeve (7) and the plastic of the respective composite or plastic disc (6).
9. Rotor according to one of claims 1 to 5, characterized in that the rotor sleeve (7) is a prefabricated fiber composite sleeve which is pushed onto the rotor (1) in the axial direction and is prestressed in the assembled state.
10. Rotor according to one of the preceding claims, characterized in that two rotor sleeves (7) are provided, which are pushed onto the rotor (1) from different end faces.
11. Rotor according to one of the preceding claims, characterized in that a balancing disc receptacle (20) is formed on an end face of the respective end disc (6) facing away from the rotor body (5), in which balancing disc receptacle a metallic balancing disc (21) is arranged for axially supporting the end disc (6).
12. Rotor according to one of the preceding claims, characterized in that in the respective end plate (6) at least one connecting channel (15) is formed as part of the cooling path (8), which is fluidly connected radially inwardly via a shaft outlet (16) to the shaft cooling channel (14) and radially outwardly to cooling channels (17) of the rotor body (5). Electrical machine (2) with a rotor (1) according to one of the preceding claims.