Rotary electrical machine, system for attaching a fan to a rotary electrical machine and method for dismantling a fan

Abstract

The present invention relates to a rotary electrical machine comprising a fan (5) configured for coupling with an end (6) of the machine shaft, wherein the fan (5) comprises a main coupling part (8) having a substantially cylindrical profile with at least two axial slots (9) that extend over the entire longitudinal length of the cylindrical profile, forming at least two curved cross-section walls; each of the curved cross-section walls comprises a raised outer rim (10) arranged on an outer surface near the free end of the main coupling part (8); and the end (6) of the shaft comprises a cylindrical inner wall (14) with an enlarged diameter part (15), wherein the transition between a smaller diameter of the inner wall (14) and the enlarged diameter part (15) forms a circular stop (16) for axial locking of the raised rim (10).

Description

“ROTATION ELECTRIC MACHINE, FAN FIXING SYSTEM FOR A ROTATION ELECTRIC MACHINE AND METHOD FOR DISASSEMBLING A FAN” FIELD OF INVENTION

[0001] The present invention relates to a rotating electric machine and, more specifically, to a rotating electric machine comprising a fan that fits with one end of the machine shaft. BACKGROUND OF THE INVENTION

[0002] Rotating electrical machines are devices used to transform electrical energy into mechanical energy, in the case of motors, and vice versa, in the case of generators. They generally consist of four basic structures: the rotor, which is the rotating energized component; a static element called the stator, which is also energized; bearings that connect the static and rotating parts; and, finally, the housing, which acts as the enclosure and facilitates integration with other auxiliary systems.

[0003] Since the operation of electrical machines involves the generation of heat, the machines may also include ventilation systems, the purpose of which is to dissipate the heat generated by the machine, keeping its internal temperature within pre-established operating limits and preventing failures and malfunctions.

[0004] In the mechanical design of rotating electrical machines, different ventilation modes can be selected, such as self-ventilated machines (TEFC), non-ventilated machines (TENV / TEAO) and forced ventilation machines (TEBC).

[0005] Ventilation solutions that use polymeric fans mounted at the end of the machine shaft are known in the state of the art.

[0006] In this type of solution, the fastening is done by pressure with a fitting part of the fan being superimposed on the end of the machine shaft, allowing for simple assembly without the need for spare parts.

[0007] Although they present advantages associated with low complexity, such solutions can present some drawbacks.

[0008] One of these drawbacks is related to the construction of the Machine itself: Since the fan is attached to the outer surface of the machine shaft end, the shaft must have a longitudinal dimension large enough to allow for mounting. Furthermore, depending on the ventilation mode adopted, the shaft must be compatible with the mounting, requiring the use of dedicated shafts for each of the different ventilation types.

[0009] A second drawback is associated with the operation of the machine: the rotation of the machine's rotor can cause a centrifugal effect that leads to external radial bending of the fitting part and, consequently, to the detachment of the snap-fit ​​fittings from the fan.

[0010] Specific solutions for assembling and disassembling fans whose construction is complex, requiring additional fixing, locking and releasing parts or devices, are also known in the state of the art.

[0011] Document CN 113695888, for example, shows equipment for assembling and disassembling a fan on a centrifugal compressor. The disassembly and assembly equipment comprises a tube connection mechanism and a pulling mechanism, wherein the tube connection mechanism is attached to a fan shaft head via an adapter block.

[0012] Document US3061342 shows a device for removing and locking a fan, which comprises, in addition to other additional construction features for fixing, a threaded connection, a disc and a spring washer. OBJECTIVES OF THE INVENTION

[0013] It is an object of the present invention to provide a rotating electric machine that incorporates a simple and efficient solution for attaching a fan.

[0014] Another objective of the present invention is to provide a rotating electric machine whose fan fixing system allows for simple fixing and simple removal of the fan.

[0015] It is another objective of the present invention to provide a rotating electric machine whose fan fixing system allows fixing on the same axis regardless of the ventilation mode of the machine.

[0016] It is another object of the present invention to provide a machine rotating electric fan whose fan fixing system allows the use of a shaft with a smaller longitudinal extension, enabling more compact machine designs.

[0017] It is yet another objective of the present invention to provide a rotating electric machine whose fan fixing system allows the fan to be fixed securely and eliminates the risk of detachment caused by the centrifugal effect generated by the rotation of the rotor.

[0018] It is another objective of the present invention to provide a fan attachment system for a rotating electrical machine that allows simplified fan attachment and removal operations.

[0019] It is another objective of the present invention to provide a fan fixing system for a rotating electrical machine that allows the fan to be fixed securely and eliminates the risk of detachment caused by the centrifugal effect generated by the rotation of the rotor.

[0020] It is another object of the present invention to provide a fan attachment system for a rotating electrical machine that allows the use of a shaft of smaller longitudinal extension, enabling more compact machine designs. BRIEF DESCRIPTION OF THE INVENTION

[0021] The present invention relates to a rotating electrical machine of the type comprising a casing housing an active core with a rotor and a stator, the rotor being mounted on a shaft, and the machine further including a fastening system for a fan that fits with one end of the shaft.

[0022] In an alternative embodiment of the invention, the component to be fixed could be another rotating component, such as a dragline or flywheel.

[0023] In a preferred embodiment of the present invention, the fan comprises a main housing portion having a substantially cylindrical profile with at least two axial slots extending along the entire longitudinal extent of the cylindrical profile, forming at least two walls of curved cross-section. The at least two walls of curved cross-section comprise a raised outer edge disposed on an outer surface proximate to the free end of the main housing portion; and the shaft end comprises a cylindrical inner wall with a portion of enlarged diameter, in which the transition between a smaller diameter of the inner wall and the portion of elongated diameter forms a circular stop for axial locking of the protruding edge.

[0024] In one embodiment of the present invention, the substantially cylindrical profile comprises at least four axial slots forming four walls of curved cross-section, and each of the walls of curved cross-section comprises an inwardly facing flange portion comprising a portion facing radially inwardly toward an interior of the fan. In one embodiment of the invention, the radially inwardly facing portion is preferably a portion inclined radially inwardly toward the axis of rotation of the fan.

[0025] This feature allows the fan of the present invention to be removed from the shaft using a common pipe wrench.

[0026] The main fitting part may have, in an embodiment of the invention, a plurality of axial slots, forming a plurality of walls of curved cross-section.

[0027] The outer surface of the main fitting portion may further comprise at least one key comprising at least one shoulder cooperating with a corresponding slot in the inner wall of the shaft end. In one embodiment of the invention, each of the curved cross-section walls has, on its outer surface, a key.

[0028] In an alternative embodiment of the present invention, the raised edge is not formed at the end of the outer surface of the main fitting portion, but rather at a location remote from a free end of the main fitting portion; and the shaft end does not comprise an elongated diameter portion, but rather a cylindrical inner wall with at least one circular groove for receiving the raised outer edge. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present invention will be described below in more detail, with reference to the attached drawings, in which:

[0030] Figure 1 - is a simplified schematic view of the attachment of a fan to a rotating electrical machine in accordance with the state of the art;

[0031] Figure 2 is a perspective view of a fan for a rotating electric machine according to the present invention;

[0032] Figure 3 is a perspective view of a section of a shaft of a rotating electrical machine according to the present invention;

[0033] Figure 4 is a cross-sectional plan view of an embodiment of a fan attachment system for a rotating electric machine according to the present invention;

[0034] Figure 5 is a schematic cross-sectional view illustrating the fan removal operation in one embodiment of a fan attachment system for a rotating electric machine according to the present invention; and

[0035] Figure 6 is a cross-sectional plan view of an alternative embodiment of a fan attachment system for a rotating electric machine in accordance with the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0036] Figure 1 is a simplified schematic illustration of the attachment of a fan to a rotating electrical machine, in accordance with the prior art. A cross-sectional view shows a fan 1 fitted onto a shaft of the electrical machine.

[0037] As can be seen in this figure, fan 1 has a central fitting part 3 that receives the end 2 of the machine shaft. Therefore, for this type of fastening, it is absolutely necessary that the end 2 of the machine shaft extends beyond the rear cover T, so that there is enough space for the fitting of fan 1.

[0038] In this known solution, the central fitting portion 3 of the fan 1 comprises a cylindrical wall with a shoulder 4 for snap-fit ​​fitting that cooperates with a corresponding depression at the shaft end 2. During machine operation, the centrifugal effect generated by the rotor rotation can cause the cylindrical wall to flex radially outward, causing the snap-fit ​​fitting to detach.

[0039] Thus, although the fixing solution shown in Figure 1 is simple, it causes a limitation in the machine shaft design and is susceptible to the fan becoming detached.

[0040] Figures 2 to 4 show a preferred embodiment of a system of fixing the fan to the rotating electric machine according to the present invention. It should be understood that although Figures 2 to 4 show the preferred embodiment of the invention in which the component is a fan, in other embodiments the component could be another rotating component, such as a dragline or flywheel.

[0041] Thus, figure 2 shows a perspective view of the fan 5 according to an embodiment of the present invention, figure 3 shows, in cross-sectional section, the end 6 of a shaft according to an embodiment of the present invention, and figure 4 shows schematically the fit between the fan 5 and the end 6 of the shaft.

[0042] As shown in the figures, the fan 5 comprises a central fitting part 7 having a main fitting part of substantially cylindrical profile 8 with at least two axial slots 9, wherein each axial slot 9 extends longitudinally across the entire cylindrical profile 8. Thus, two broken walls of curved cross-section are formed, which gives the cylindrical profile 8 a radial resilience.

[0043] In the embodiment shown in Figure 2, the substantially cylindrical profile 8 comprises four axial slots 9, so that the cylindrical profile is formed by four walls of curved cross-section (in the embodiment of the figures, in a quarter circle). Naturally, the number of axial slots 9 could vary in other embodiments, forming a greater or lesser number of walls of curved cross-section.

[0044] In the embodiment illustrated in the figures, the four axial slots 9 are arranged equidistantly in the substantially cylindrical profile 8. However, in other embodiments, the four axial slots could be formed at unequal distances.

[0045] On the outer surface of the main fitting part 8 a raised edge 10 is formed. Thus, in the embodiment shown in the figures, each of the four curved cross-section walls has a raised outer edge 10. Preferably, the raised edge 10 is formed in a portion close to the free end of the main fitting part 8.

[0046] The outer surface of the main fitting part 8 may further comprise at least one projection 11 cooperating with a corresponding slot 12 on the inner surface of the shaft end 6, forming a key. In the illustrated embodiment, the outer surface of the main fitting part 8 comprises two projections 11 that cooperate with the slot 12.

[0047] From the end of the main fitting part 8 there projects an inwardly facing tab portion 13. In the embodiment shown in the figures, each of the curved cross-section walls has a corresponding inwardly facing tab portion 13.

[0048] As illustrated in Figures 3 to 5, the cylindrical inner wall 14 of the end 6 of the machine shaft has an enlarged diameter portion 15. Thus, the transition between the smaller diameter of the inner wall 14 and the elongated diameter portion 15 forms a circular stop 16 for axial locking of the protruding edge 10 of the main engagement portion 8.

[0049] Thus, the cooperation between the raised edge 10 and the circular stop 16 forms a snap-fit ​​type fit, in which the fit occurs by inserting the main fitting portion 8 internally to the shaft end 6. That is, by inserting the main fitting portion 8 internally to the shaft, the curved cross-section walls are flexed radially inwardly by the interaction between the raised edge 10 and the inner wall of the shaft end 6 until the raised edge 10 is received by the enlarged diameter portion 15. After the raised edge 10 is received in the enlarged diameter portion 15, the main fitting portion 8 remains axially locked inside the shaft end 6 by the interaction between the raised edge 10 and the circular stop 16.

[0050] The fan 5, which is preferably made of a polymeric material, further comprises a cylindrical hub portion 17 from which the main fitting portion 8 projects. The cylindrical hub portion 17 comprises two circular edge walls 18, 19 which rest against the outermost surface of the shaft end 6 when the main fitting portion 8 is fitted inside the shaft end 6.

[0051] It should be noted that the fan could be manufactured as a single piece or multiple segmented parts fastened together. In alternative embodiments of the invention, the fan could be made of another material, such as metal, or even a joint between a polymeric fan part and a metal fan part.

[0052] In one embodiment of the invention, the circular edge walls 18, 19 have a recess between them which can, if necessary, accommodate a sealing O-ring.

[0053] As mentioned previously and as best illustrated in Figures 4 and 5, an inwardly facing tab portion 13 projects from the end of the main fitting part 8. The tab portion 13 comprises an inwardly facing portion 13a toward the interior of the fan. In the embodiment shown in the figures, the radially inwardly facing portion 13a is preferably a portion inclined radially inwardly toward the axis of rotation of the fan.

[0054] Thus, in the embodiment shown in the figures, each of the curved cross-section walls has a corresponding inwardly facing flap portion 13 with a flap portion 13a radially inclined inwardly towards the axis of rotation of the fan.

[0055] As schematically illustrated in Figure 5, this feature of the main fitting part 8 makes it possible to use a tubular tool, such as a common pipe wrench C, to remove the fan 5 from the end of the shaft.

[0056] In the solution of the present invention, the pipe wrench C is inserted through the hub portion 17 of the fan so as to exert an axial force F on the radially inwardly inclined flap portions 13a, flexing the flap portions 13 radially inwardly and consequently flexing the curved cross-section walls radially inwardly, displacing the protruding edge 10 of the circular stop 16 and unlocking the fan 5. Once the axial locking is undone, the fan can be moved off the shaft without great effort.

[0057] Therefore, in the solution of the present invention, the fan is fitted internally to the shaft, which eliminates the need for a shaft end with a free external surface for fan attachment. This can both allow for a more compact machine design and allow this fan attachment solution to be used in machines that utilize different ventilation modes (different shaft designs).

[0058] The solution of the present invention also allows for simple fixing and the simple removal of the fan.

[0059] Fixing it to the inside of the shaft end also eliminates the risk of detachment caused by the centrifugal effect generated by the rotor rotation.

[0060] Figure 6 shows an alternative embodiment of the fastening system according to the present invention. Thus, the unchanged features in this embodiment will be described with the aid of the same reference numerals, while the changed features will use new numerals.

[0061] In this embodiment, the raised edge 100 is not formed at the end of the outer surface of the main engagement portion 8, but rather at a location spaced from the tab portion 13 by about 2 / 3 of the longitudinal (axial) dimension of the main engagement portion. Correspondingly, in this embodiment, the inner surface of the shaft end 6 does not have the diameter enlargement, but rather a circular groove 150 positioned to receive the raised edge 100.

[0062] This embodiment presents the same advantages associated with the embodiment of Figures 2 to 5, except for the possibility of using a pipe wrench to remove the fan. In this embodiment, the fan is removed by exerting an axial force against the shaft end until the edge 100 detaches from the circular groove 150.

[0063] Having described examples of embodiments of the present invention, it should be understood that the scope of the present invention encompasses other possible variations of the described inventive concept, being limited only by the content of the appended claims, including possible equivalents.

Claims

CLAIMS 1. A rotating electric machine of the type comprising a housing housing an active core with a rotor and a stator, the rotor being mounted on a shaft, and the machine further including a fan (5) configured to engage with an end (6) of the shaft, the machine being characterized in that: the fan (5) comprises a main engaging part (8) having a substantially cylindrical profile with at least two axial slots (9) extending over the entire longitudinal extent of the cylindrical profile, forming at least two walls of curved cross-section; each of the walls of curved cross-section comprises a raised outer edge (10) arranged on an outer surface close to the free end of the main engaging part (8);and the end (6) of the shaft comprises a cylindrical inner wall (14) with an enlarged diameter portion (15), wherein the transition between a smaller diameter of the inner wall (14) and the elongated diameter portion (15) forms a circular stop (16) for axial locking of the protruding edge (10).; Machine according to claim 1, characterized in that each of the curved cross-section walls comprises an inwardly facing flap portion (13) comprising an inwardly facing part (13a) towards an interior of the fan. Machine according to claim 2, characterized in that the inwardly facing portion (13a) comprises a radially inwardly inclined portion (13a) towards the geometric axis of rotation of the fan. Machine according to any one of claims 1 to 3, characterized in that an outer surface of the main fitting part (8) comprises at least one shoulder (11) which cooperates with a corresponding slot (12) in the inner wall (14) of the shaft end (6) to form a key.

5. A rotating electrical machine of the type comprising a housing housing an active core with a rotor and a stator, the rotor being mounted on a shaft, and the machine further including a fan (5) configured to engage with an end (6) of the shaft, the machine being characterized in that: the fan (5) comprises a main housing portion (8) having a substantially cylindrical profile with at least two axial slots (9) extending over the entire longitudinal extent of the cylindrical profile, forming at least two walls of curved cross-section; each of the walls of curved cross-section comprises a raised outer edge (100) disposed on an outer surface at a location remote from a free end of the main housing portion (8); and the end (6) of the shaft comprises a cylindrical inner wall (14) with at least one circular groove (150) for receiving the raised outer edge (100).

6. Fixing system for a fan (5) that is fitted to one end (6) of a shaft of a rotating electrical machine, the fixing system being characterized by: a main fitting part (8) provided on the fan (5), the main fitting part (8) having a substantially cylindrical profile with at least two axial slots (9) that extend over the entire longitudinal extension of the cylindrical profile, forming at least two walls of curved cross-section; each of the walls of curved cross-section comprising a raised outer edge (10) arranged on an outer surface close to the free end of the main fitting part (8);and a fitting portion formed internally to the end (6) of the shaft, the fitting portion being configured to receive the main fitting portion (8) and comprising a cylindrical inner wall (14) with an enlarged diameter portion (15), in which the transition between a smaller diameter of the inner wall (14) and the elongated diameter portion (15) forms a circular stop (16) for axial locking of the protruding edge (10).; 7. Fixation system according to claim 6, characterized in that each of the curved cross-section walls comprises an inwardly facing tab portion (13) comprising an inwardly facing part (13a) towards an interior of the fan.

8. Fixation system according to claim 7, characterized in that the inwardly facing part (13a) comprises a radially inwardly inclined part (13a) towards the geometric axis of rotation of the fan.

9. Fastening system according to any one of claims 6 to 8, characterized in that an outer surface of the main fitting part (8) comprises at least one shoulder (11) which cooperates with a corresponding slot (12) in the inner wall (14) of the shaft end to form a keyway.

10. Fixing system for a fan (5) that is fitted to one end (6) of a shaft of a rotating electrical machine, the fixing system being characterized by: a main fitting part (8) provided on the fan (5), to a main fitting part (8) comprising a substantially cylindrical profile with at least two axial slots (9) that extend over the entire longitudinal extent of the cylindrical profile, forming at least two walls of curved cross-section; each of the walls of curved cross-section comprising a raised outer edge (100) arranged on an outer surface at a location remote from a free end of the main fitting part (8);and a fitting portion formed internally to the end (6) of the shaft, the fitting portion being configured to receive the main fitting portion (8) and comprising a cylindrical inner wall (14) with at least one circular groove (150) for receiving the protruding outer edge (100).; 11. A method for disassembling a fan (5) that is fitted to an end (6) of a shaft of a rotating electrical machine, characterized in that the fan (5) has a hub portion (17) that is fixed to the end (6) of the shaft by a fastening system as defined in any one of claims 6 to 10, the method comprising: inserting a tubular tool through the hub portion (17) of the fan (5); and exerting axial force (F) on the inwardly facing flap portions (13) of the curved cross-section walls, flexing the inwardly facing flap portions (13) radially inwardly and displacing the protruding outer edge (10) of the circular stop (16) to unlock the fan (5); and displacing the fan (5) away from the end (6) of the shaft.

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