Decoupling device for a wave generator with a permanent magnet-equipped rotor

Abstract

Decoupling arrangement for a shaft generator with a permanent magnet-equipped rotor (4) and a solid stator housing (1), wherein the permanent magnet-equipped rotor (4) is attached to a drive shaft (11) of a ship by means of an adapter ring (8) and fastening bolts (10), characterized by that at least three radially distributed cantilever arms (12) are attached to the stand housing (1) on each stand end face, between cantilever arms (12) and inner surface (17) of the runner (4) at least one insert element (15) is arranged per cantilever arm (12) and Each cantilever arm (12) has at least one push-off opening (16) arranged.

Description

[0001] The invention relates to a decoupling device for a shaft generator without its own bearings, featuring a rotor equipped with permanent magnets. The rotor consists of a rotor body with permanent magnets screwed onto it. The rotor body is directly connected to the propeller shaft of a ship.

[0002] The use of shaft generators with permanent magnet rotors to supply the ship's electrical system with power is well-established in various applications and is steadily increasing. In these applications, the permanent magnet rotors are typically mounted directly on the main drive shaft. In the event of damage to the stator, the electrical distribution circuit, or the rotor itself, the shaft generator must be stopped relatively quickly, as the continued rotation of the permanent magnet rotor constantly induces a voltage in the stator. This significant voltage can lead to substantial damage, particularly overheating of the stator, potentially resulting in a fire. Therefore, it is essential to stop the drive shaft as quickly as possible.This standstill of the drive shaft should only occur for a short period, as the ship becomes unmaneuverable and drifts helplessly without steering if the drive shaft is not rotating. It is already known to decouple such permanent magnet-equipped rotors from the main drive shaft and reliably prevent further rotation by locking the rotor in place. Only when the rotor is locked and its connection to the main drive shaft is released can the shaft restart and be driven again. Since these are generally large electric shaft generators, a relatively long time may be required to lock the rotor. Therefore, the standstill time of the drive shaft must be minimized as much as possible.

[0003] In WO 2016 / 162 595 A1, EP 3 127 224 B1, an electric machine is described with a permanent magnet-equipped rotor and two successive, separate rotor sections, each with permanent magnets mounted on it, which generate a magnetic field with a specific pole pitch. The two-part rotor has a coupling system for each rotor section to connect these sections to the rotor shaft or to connect the two rotor sections. One rotor section is rotatable and lockable at an angle relative to the other rotor section, the angle corresponding exactly to the pole pitch, thus allowing the two rotor sections to be separated. This effectively eliminates the current flow. Consequently, the permanent magnets induce virtually no voltages in the stator windings, even if the rotor continues to rotate due to damage to the stator winding.

[0004] EP 3 681 019 A1 describes another device for separating a rotor equipped with permanent magnets from the shaft of a permanent magnet excited electric machine. A special drive system can selectively connect the shaft of an electric machine, consisting of a stator and rotor, to the rotor as needed, or disconnect it in the event of damage. This mechanical disconnection system is arranged between the rotor and the shaft such that the rotor can be axially displaced relative to the shaft within a specific range. The mechanical disconnection system is configured to mechanically connect the rotor to the shaft in a first state and to mechanically disconnect the rotor from the shaft in a second state, so that the rotor neither drives the shaft nor can the shaft set the rotor in rotation.

[0005] EP 3 624 309 A1 presents individual, specially shaped permanent magnet modules for a permanent magnet-equipped rotor. Each permanent magnet module consists of a base plate and a permanent magnet element mounted on the base plate. The base plate comprises a lower section and an upper section, which is positioned between the lower section and the permanent magnet element. The permanent magnet modules are arranged to form specific subgroups, with the permanent magnet modules of the different subgroups differing from each other in their positions relative to the lower sections of the base plates. This creates modules that can be axially aligned and circumferentially displaced as needed, provided the lower sections of these permanent magnet modules are aligned axially aligned and circumferentially offset.Thus, the permanent magnet elements of the permanent magnet modules can, for example, be arranged and moved in inclined rows on a surface of the rotor.

[0006] In a publication by the company "THE SWITCH," titled "The Switch Assembly Instructions DA 0229 PMM 1000 F00," the assembly process for an intermediate shaft in a small-scale generator with a permanent magnet rotor is described in detail. Furthermore, explanations are provided for installing the generator with a separate intermediate shaft into the ship. Finally, a description is given for disengaging the permanent magnet rotor from the ship's propeller shaft. This involves radially fixing the entire rotor in the housing using axially arranged bolts. The connection between the shaft and the permanent magnet rotor, created by a specially designed conical coupling, is then released.

[0007] A video produced by THE SWITCH, titled "Permanent Magnet Shaft Generator Commissioning," available online at "theswitch.com / download-center / videos," presents a stylized assembly process for a shaft generator. The video shows a section of the ship's propeller shaft being inserted into the stator of the shaft generator and fitted with a permanently excited rotor. The video then demonstrates connecting the shaft section to the rotor and securing the rotor. Finally, it shows the installation and alignment of the shaft generator with the propeller shaft within the ship.

[0008] CN 115 483 805 A describes an assembly method for a permanent magnet shaft generator, in which a permanent magnet-equipped rotor is secured with mounting bolts to reduce the magnetic attraction within the generator. For inspection, the propeller shaft and the intermediate shaft are successively suspended in the housing. This involves lifting the generator within the housing so that the stator can be removed using a support frame. Care is taken to ensure that the support frame does not come into contact with the rotor coil. After rotating and repositioning the main motor, repairs can be carried out. Both axial and radial ends of the stator body are each fitted with a spindle frame.During lifting, a steel wire rope is guided through a bolt hole in a rotor shaft flange and a lifting ring, thus fixing the rotor shaft and stator body during the lifting process and engaging eight T-shaped and L-shaped brackets without bolts. This allows all parts to move slightly back and forth, ensuring that the air gaps around the rotor coil and stator coil remain uniformly spaced.

[0009] The invention is based on the objective of creating a structurally simple decoupling arrangement for a large shaft generator with a permanent magnet-equipped rotor without its own bearings, which makes it possible in the event of damage to decouple a permanent magnet-equipped rotor from the drive shaft of, for example, a ship in a shorter time than before and to reliably and permanently mechanically fix the rotor in order to be able to switch off the shaft generator without energy.

[0010] The problem is solved according to the invention by the features of the preamble and the characterizing part of the first claim. Further advantageous embodiments are described in the dependent claims.

[0011] According to the invention, in the decoupling arrangement for a shaft generator with a permanent magnet-equipped rotor 4 and a solid stator housing 1, the permanent magnet-equipped rotor 4 is attached to a drive shaft 11, for example, of a ship, by means of an adapter ring 8 and suitable and appropriately dimensioned mounting bolts 10. At least three radially distributed cantilever arms 12 are attached to the stator housing 1 on each end face. Between the cantilever arms 12 and the inner surface 17 of the rotor 4, at least one specially dimensioned shim element 15 is arranged for each cantilever arm 12 in a manner that allows for easy removal. If required by the design, several subdivided shim elements 15 may also be arranged. At least one ejection opening 16 is arranged in each cantilever arm 12. Depending on the design, several ejection openings 16 may also be provided. The cantilever arms 12 are connected by means of a screw connection or...The support arms 12 are connected to the end faces of the support housing 1 by similarly functioning detachable connections. The cantilever arms 12 hold the runner 4 on the inner surface 17 of the runner body 5. Special shims 15 enable a positive fit between the individual cantilever arms 12 and the runner body 5. Ejection openings 16 are formed in the cantilever arms, which are preferably provided with an internal thread. These ejection threads in the cantilever arm 12 allow for the easy installation and removal of the shims 15 in a short time using suitable screws.

[0012] It is advantageous if, in the decoupling arrangement for a shaft generator with a permanent magnet-equipped rotor, the adapter ring 8 is designed in one, two, or more parts and is simultaneously designed in such a way that it can already be used as a mounting template. It then serves, in particular, as a drilling template for the drive shaft 11 of, for example, a ship.

[0013] In the simplest case, the decoupling arrangement for a wave generator with a permanent magnet-equipped rotor 4 has threaded openings 16 in each of which a release screw 18 can be inserted, i.e., typically screwed in, so that the rotor can be easily and quickly displaced radially and then axially and fixed in place by turning the release screws 18. However, several threaded release openings 16 can also be arranged, in which case several smaller release screws 18 can be used.

[0014] It is also possible that in the decoupling arrangement for a shaft generator with a permanent magnet-equipped rotor 4, additional recesses 21 for the flow of separately supplied cooling air are arranged in or on the adapter ring 8.

[0015] As a result of the novel decoupling arrangement, the rotor is precisely centered in the stator. A further advantage of this decoupling arrangement is that the permanent magnet-equipped rotor (usually with screwed-on permanent magnets) can be held securely centered to the stator lamination stack during transport and later during the assembly process. Another significant advantage is that, if required, the novel adapter ring 8 can be easily used as a mounting template for the drive shaft.

[0016] The invention will be explained in more detail below using an exemplary embodiment with reference to the figure. Fig. Figure 1 shows an arrangement according to the invention for fixing the runner. Fig. Figure 2 shows a possible embodiment of an adapter ring 8

[0017] In a preferred embodiment, eight L-shaped cantilever arms 12 are arranged and fastened in the decoupling arrangement, with four arranged radially distributed at 90 degrees on each end face of the stator 3. These eight cantilever arms 12 are designed to be mechanically stable enough to reliably absorb both the entire mass of the rotor 4 and the maximum magnetic forces exerted by the permanent magnets 7. The cantilever arms 12 are connected externally to the end faces of the stator housing 1 by means of one or more suitable screw connections or similar detachable connections. The cantilever arms 12 hold the rotor 4 on the inner surface 17 of the rotor body 5. Special shims 15 enable a positive fit between the individual cantilever arms 12 and the rotor body 5. Ejection openings 16, which are provided with an internal thread, are formed in the cantilever arms.The shims 15 can be easily installed and removed in just a few steps using suitable ejector screws 18 via these ejector threads in the cantilever arm 12. The shims 15 are removed during operation of the shaft generator.

[0018] If a fault occurs in the shaft generator or one of the downstream electrical systems during ship operation, the rotating rotor 4 must be slowed down and stopped as quickly as possible. This is done by stopping the relevant drive shaft 11. This stopping must only be for a relatively short time, as the ship is unmaneuverable without propulsion. During this time, the protective shields (not shown), which cover the motor's interior, must be immediately removed from the end faces of the stator housing 1. Using a turning device 9 of the drive shaft 11, the bores in the cantilever arms 12 are aligned with the bores in the rotor body by slightly rotating the drive shaft 11. The shims 15 are then inserted between the individual cantilever arms 12 and the inner surface 17 of the rotor body 5.The cantilever arms 12 and the rotor body 5 are then screwed together using the shims 15. Next, the fastening bolts 10 between the adapter ring 8 and the drive shaft 11 are removed, and the entire stator, with the rotor 4 firmly screwed to the stator housing 1, is moved axially along the shaft axis until the adapter ring 8 no longer rests on the centering rim of the drive shaft 11, has sufficient clearance, and any contact between the drive shaft 11 and the split adapter ring 8 is reliably prevented, even during subsequent rotation. The axial movement of the entire shaft generator relative to the drive shaft 11 can advantageously be achieved simply by means of additional set screws. The drive shaft 11 can then be started again. The adapter ring 8 is split and simultaneously serves as a drilling template for the mounting holes in the drive shaft 11.

[0019] In the Fig. Figure 2 shows a split adapter ring 8 according to the invention; however, the division is not shown in the figure. In this embodiment, eight bores 19 are arranged evenly spaced within the first partial circle for the passage of the fastening bolts 10, which connect the adapter ring 8 to the drive shaft 11. These serve simultaneously as a drilling template during assembly, since the drive shaft and the shaft generator are usually manufactured and supplied by different companies. This reliably prevents a potential error, because if the bores 19 for fastening to the drive shaft 11 do not align precisely with the bores of the drive shaft 11, significant financial damage can result.

[0020] A significant delay in assembly occurred until this error was rectified. Two rows of bores for the mounting bolts 20 of the adapter ring 8 to the rotor body 5 are arranged externally in two partial circles and radially distributed. An additional inner rotor ring is arranged inside the rotor body 5, which is preferably welded to the rotor body 5. The adapter ring 8 is arranged on the inner rotor ring. The mounting bolts 20 for attaching the split adapter ring 8 are smaller than the mounting bolts to the rotor shaft 11.In this embodiment, for effective cooling of the rotor body 5, additional recesses 21 for separately supplied cooling air are arranged on the outer circumference of the adapter ring 8 in this decoupling arrangement for a shaft generator with a permanent magnet-equipped rotor, thereby preventing excessive heating of the rotor body 5 and thus of the heat-sensitive permanent magnets.

[0021] In the event of damage, the invention can be used as a reliable and quickly deployable decoupling arrangement for a shaft generator with a permanent magnet-equipped rotor 4 on drive shafts 11, particularly for ships. Reference symbol list 1 stand housing 2 Stand plate package 3 Stand end 4 runners 5 runner bodies 6 runner mounting holes 7 permanent magnets 8 Adapter ring 9 Gymnastics apparatus 10 fastening bolts 11 Drive shaft 12 Cantilever arms (L-shaped) 13 Cantilever drilling 14 Cantilever bolt 15 Side dish element 16 Pressure opening 17 Inner mantle surface 18 Ejector screw 19 holes for mounting bolts to the drive shaft 20 holes for mounting bolts with the runner body 21 cutouts

Claims

[1] Decoupling arrangement for a shaft generator with a permanent magnet-equipped rotor (4) and a solid stator housing (1), wherein the permanent magnet-equipped rotor (4) is attached to a drive shaft (11) of a ship by means of an adapter ring (8) by means of fastening bolts (10), characterized by , that at least three radially distributed cantilever arms (12) are attached to the stand housing (1) on each stand end face, between cantilever arms (12) and inner surface (17) of the runner (4) at least one insert element (15) is arranged per cantilever arm (12) and Each cantilever arm (12) has at least one push-off opening (16) arranged. [2] Decoupling arrangement for a wave generator with a permanent magnet-equipped rotor (4) according to claim 1, characterized by , that the adapter ring (8) is designed as a one- or multi-part mounting template. [3] Decoupling arrangement for a wave generator with a permanent magnet-equipped rotor (4) according to claim 1, characterized by , that a thread is provided in each of the ejection openings (16) into which an ejection screw (18) can be arranged. [4] Decoupling arrangement for a wave generator with a permanent magnet-equipped rotor (4) according to claim 1, characterized by , that recesses (21) for the flow of supplied cooling air are arranged in or on the adapter ring (8).

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