Decoupling assembly for a wave generator with a rotor provided with permanent magnets

Abstract

The invention relates to a decoupling assembly for a wave generator with a rotor provided with permanent magnets. The object of the invention is to create a simple decoupling assembly which, in the event of damage, enables a rotor provided with permanent magnets to be quickly decoupled from the drive shaft of a ship and to reliably and permanently fix the rotor in place. According to the invention, the rotor (4) is secured to a drive shaft (11) by an adapter ring (8) using securing bolts (10). On the stator housing (1), at least three radially distributed cantilever arms (12) are secured per stator end side. One insert element (15) per cantilever arm (12) is arranged between the cantilever arms (12) and the inner casing surface (17) of the rotor (4). At least one forcing opening (16) is arranged in each cantilever arm (12). The cantilever arms (12) are connected to the stator end sides of the stator housing (1) by means of a screw connection. The cantilever arms (12) hold the rotor (4) on the inner casing surface (17) of the rotor body (5). Special insert elements (15) allow for an interlocking connection between the individual cantilever arms (12) and the rotor body (5). Forcing openings (16) are formed in the cantilever arms, which are provided with an internal thread. Via these forcing threads in the cantilever arm (12), the insert elements (15) can be easily installed and removed in just a few steps with an appropriate screwing action.

Description

[0001] Decoupling arrangement for a wave generator with a permanent magnet rotor

[0002] The invention relates to a decoupling device for a shaft generator without its own bearings and with a permanent magnet-equipped rotor. The rotor consists of a rotor body with permanent magnets screwed onto it. The rotor body is directly connected to the drive shaft of a ship.

[0003] The use of shaft generators with permanent magnets (i.e., permanent magnet-equipped rotors) to supply the on-board electrical system with electrical power on ships is known from various applications and continues to grow. The permanent magnet-equipped rotors are usually located directly on the main drive train. In the event of damage to the stator and / or the electrical distribution circuit and / or the rotor itself, the shaft generator must be stopped relatively quickly, as the continued rotation of the permanent magnet-equipped rotor constantly induces a voltage in the stator. This considerable voltage can cause significant damage and, in particular, overheating of the stator and even fire. Therefore, it is necessary to stop the drive shaft as quickly as possible.This standstill of the drive shaft should only occur for a short period of time, as the ship is unable to maneuver and drifts rudderlessly in the water without the drive shaft 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. Only when the rotor is locked and its connection to the main drive shaft is released can the shaft start up again and continue to be driven. Since these are usually large electrical wave generators, a relatively long time may be required to lock the rotor. The downtime of the drive shaft must therefore be minimized as much as possible.

[0004] WO 2016 / 162595 EP 3 127 224 B1 describes an electrical machine with a rotor equipped with permanent magnets and two consecutive, separate rotor sections on which permanent magnets are arranged, which generate a magnetic field with a specific pole pitch. The two-part rotor has a coupling system for each rotor section for connecting these rotor sections to the rotor shaft or for connecting the two rotor sections. One rotor section is arranged so that it can be rotated and locked relative to the other rotor section by an angle, whereby the angle corresponds exactly to the pole pitch and therefore it is still possible to separate the two rotor sections from each other. In this case, the current flow linkages are essentially set to zero. As a result, the permanent magnets induce almost no voltages in the stator windings, even if the rotor continues to rotate due to damage to the stator winding.

[0005] EP 3 681 019 A1 describes another device for separating a rotor equipped with permanent magnets from the shaft of a permanent magnet-excited electrical machine. A special drive system can either connect the shaft of an electrical machine, which consists of a stator and rotor, to the rotor when required, or separate it when required in the event of damage. This mechanical separation system is arranged between the rotor and the shaft in such a way that the rotor can be axially displaced relative to the shaft within a specific range. The mechanical separation system is configured to mechanically connect the rotor to the shaft in a first state and to mechanically separate the rotor from the shaft in a second state, such that the rotor does not drive the shaft or that the rotor cannot be rotated by the shaft.

[0006] EP 3 624 309 A1 presents individual, specially shaped permanent magnet modules for a rotor equipped with permanent magnets. Each permanent magnet module consists of a base plate and a permanent magnet element fastened to the base plate. The base plate comprises a lower section and an upper section, which is arranged between the lower section and the permanent magnet element. The permanent magnet modules are arranged in such a way that they form special subgroups, whereby the permanent magnet modules of the different subgroups differ from one another in their positions relative to the upper sections of the base plates in relation to the lower sections of the base plates. This creates modules which can be displaced axially one after the other and circumferentially if necessary if the lower sections of these permanent magnet modules are aligned axially one after the other and offset in the circumferential direction.This means that the permanent magnet elements of the permanent magnet modules can be arranged and moved, for example, in diagonal rows on a surface of the rotor. A publication by “THE SWITCH” entitled “The Switch Assembly Instructions DA 0229 PMM 1000 F00” describes in detail the assembly process of an intermediate shaft in a smaller generator with a permanently excited rotor. It also provides explanations for installing the generator with a separate intermediate shaft in the ship. Finally, there is a description of how to decouple the permanently excited rotor from the ship's shaft. The entire rotor is radially secured in the housing using axially arranged bolts. This loosens the connection between the shaft and the permanently excited rotor, which is created by a specially designed cone coupling.

[0007] A video created by THE SWITCH entitled "Permanent Magnet Shaft Generator Commissioning," available online at "theswitch.com / download-center / videos," presents a stylized assembly process for a shaft generator. In this video, a portion of the ship's shaft is inserted into the stator of a shaft generator and mounted with a permanently excited rotor fixed within it. The video then shows how the ship's shaft section is connected to the rotor and how to remove the rotor's locking mechanism. Finally, the video shows the installation and alignment of the shaft generator with respect to the drive shaft within a ship.

[0008] The invention is based on the object of creating a structurally simple decoupling arrangement for a large wave generator with a permanent magnet-equipped rotor without its own bearings, which makes it possible to decouple a permanent magnet-equipped rotor from the drive shaft of a ship, for example, in the event of damage in a shorter time than before and to reliably and permanently mechanically fix the rotor in order to be able to switch off the power to the wave generator.

[0009] The object is achieved according to the invention with the features of the preamble and the characterizing part of the first patent claim. Further advantageous embodiments are described in the subclaims. According to the invention, in the decoupling arrangement for a wave generator with a permanent magnet-equipped rotor 4 and a solid stator housing 1, the permanent magnet-equipped rotor 4 is fastened to a drive shaft 11, for example, of a ship, by means of an adapter ring 8 using suitable and appropriately dimensioned fastening bolts 10. At least three radially distributed cantilever arms 12 are fastened to each stator end face on the stator housing 1. Between the cantilever arms 12 and the inner surface 17 of the rotor 4, at least one specially dimensioned shim element 15 for each cantilever arm 12 is arranged for easy removal. If necessary, several subdivided shim elements 15 can also be arranged depending on the design.At least one pressure opening 16 is arranged in each cantilever arm 12.

[0010] Depending on the design, several forcing openings 16 can also be provided. The cantilever arms 12 are connected to the stator end faces of the stator housing 1 by means of a screw connection or similarly acting detachable connections. The cantilever arms 12 hold the rotor 4 on the inner surface 17 of the rotor body 5. Special shim elements 15 enable a positive connection between the individual cantilever arms 12 and the rotor body 5. Forcing openings 16 are formed in the cantilever arms, which are preferably provided with an internal thread. These forcing threads in the cantilever arm 12 allow for simple installation and removal of the shim elements 15 within a short time and in just a few steps using suitable screws.

[0011] It is advantageous if, in the decoupling arrangement for a wave generator with a permanent magnet rotor, the adapter ring 8 is designed in one, two, or multiple parts and, at the same time, is constructed in such a way that it can already be used as an assembly template. It then serves, in particular, as a drilling template for the drive shaft 11 of, for example, a ship.

[0012] In the simplest case, in the decoupling arrangement for a wave generator with a rotor 4 equipped with a permanent magnet, a thread is introduced into each of the forcing openings 16, into each of which a forcing screw 18 can be arranged, i.e. can generally be screwed, so that the rotor can be easily and with little effort first radially and then axially displaced and fixed by turning the forcing screws 18. However, several threaded forcing openings 16 can also be arranged, in which case several smaller forcing screws 18 can be used. It is also possible for additional recesses 21 to be arranged in or on the adapter ring 8 for the flow of separately supplied cooling air in the decoupling arrangement for a wave generator with a rotor 4 equipped with a permanent magnet.

[0013] As a result, the innovative decoupling arrangement secures the rotor precisely centrally in the stator. Another advantageous feature of the decoupling arrangement is that the permanent magnet-equipped rotor (usually with screwed-on permanent magnets) can be firmly locked centrally to the stator core during transport and later during the assembly process. Another major advantage is that, if necessary, the innovative adapter ring 8 can be easily used as an assembly template for the drive shaft.

[0014] The invention will be explained in more detail below in an embodiment with reference to the figure.

[0015] Fig. 1 shows an arrangement according to the invention for fixing the rotor. Fig. 2 shows a possible embodiment of an adapter ring 8

[0016] In a preferred embodiment, eight L-shaped cantilever arms 12 are arranged and fastened in the decoupling arrangement, with four being arranged on each stator end face 3, radially distributed by 90 degrees. These eight cantilever arms 12 are designed to be mechanically stable enough to safely 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 stator end faces of the stator housing 1 by means of one or more suitable screw connections or similarly acting detachable connections. The cantilever arms 12 hold the rotor 4 on the inner surface 17 of the rotor body 5. Special shim elements 15 enable a positive connection between the individual cantilever arms 12 and the rotor body 5. Press-off openings 16, which are provided with an internal thread, are formed in the cantilever arms.These forcing threads in the cantilever arm 12 allow for easy installation and removal of the shim elements 15 in just a few steps using suitable forcing screws 18. The shim elements 15 are removed while the shaft generator is in operation. If damage occurs to 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 may only occur for a relatively short time, as the ship is unable to maneuver without propulsion. During this time, so-called protective shields (not shown), which cover the interior of the motor, must be removed immediately from the front sides of the stator housing 1.By means of a turning device 9 of the drive shaft 11, the holes in the cantilever arms 12 are aligned with the holes in the rotor body by slightly twisting the drive shaft 11. The shim elements 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 shim elements 15. The fastening bolts 10 between the adapter ring 8 and the drive shaft 11 are now 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 edge of the drive shaft 11, has sufficient clearance and any contact between the drive shaft 11 and the split adapter ring 8 is reliably excluded, even during its subsequent rotation.The axial displacement of the entire wave generator relative to the drive shaft 11 can advantageously be achieved simply by using additional forcing screws. The drive shaft 11 can then be re-engaged. The adapter ring 8 is split and also serves as a drilling template for the mounting holes in the drive shaft 11.

[0017] Figure 2 depicts a split adapter ring 8 according to the invention; however, the pitch is not shown in the figure. Evenly distributed within the first pitch circle, in this embodiment, eight holes 19 are arranged for the passage of the fastening bolts 10, which connect the adapter ring 8 to the drive shaft 11. These also serve as a drilling template during assembly, since the drive shaft and the wave generator are generally manufactured and supplied by different manufacturers. This reliably prevents the possibility of errors, because if the holes 19 for fastening to the drive shaft 11 are not exactly aligned with the holes in the drive shaft 11, this would result in significant financial loss and considerable delays during assembly until this error can be rectified.Arranged on the outside in two partial circles and radially distributed, there are two rows of holes for the fastening bolts 20 of the adapter ring 8 to the rotor body 5. An additional rotor inner 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 rotor inner ring. The fastening bolts 20 for fastening the split adapter ring 8 are smaller than the fastening bolts to the rotor shaft 11. For effective cooling of the rotor body 5, in this embodiment, additional recesses 21 for separately supplied cooling air to flow through are arranged on the outside of the circumference of the adapter ring 8 in this decoupling arrangement for a wave generator with a rotor equipped with permanent magnets on the adapter ring 8, whereby excessive heating of the rotor body 5 and thus of the permanent magnets, which are sensitive to heating, is prevented.

[0018] In the event of damage, the invention can be used as a reliable and quickly deployable decoupling arrangement for a wave generator with a permanent magnet rotor 4 on drive shafts 11, in particular for ships.

[0019] List of reference symbols

[0020] 1 stand housing

[0021] 2 stator cores

[0022] 3 Post end

[0023] 4 runners

[0024] 5 rotor bodies

[0025] 6 rotor mounting hole

[0026] 7 permanent magnets

[0027] 8 adapter ring

[0028] 9 Gymnastic equipment

[0029] 10 fastening bolts

[0030] 11 Drive shaft

[0031] 12 cantilever arm (L-shaped)

[0032] 13 Cantilever hole

[0033] 14 Cantilever screw

[0034] 15 Side dish element

[0035] 16 Pressure release opening

[0036] 17 Inner jacket surface

[0037] 18 Forcing screw

[0038] 19 Hole for fastening bolt with the drive shaft

[0039] 20 holes for fastening bolts to the rotor body

[0040] 21 recesses

Claims

Patent claims:

1. Decoupling arrangement for a wave generator with a rotor (4) equipped with permanent magnets and a solid stator housing (1), wherein the rotor (4) equipped with permanent magnets is fastened to a drive shaft (11) of a ship with an adapter ring (8) by means of fastening bolts (10), characterized in that at least three radially distributed cantilever arms (12) are fastened to each stator end face on the stator housing (1), at least one shim element (15) is arranged for each cantilever arm (12) between the cantilever arms (12) and the inner casing surface (17) of the rotor (4), and at least one pressure-releasing opening (16) is arranged in each cantilever arm (12).

2. Decoupling arrangement for a wave generator with a permanent magnet equipped rotor (4) according to claim 1, characterized in that the adapter ring (8) is designed as a one-part or multi-part assembly template.

3. Decoupling arrangement for a wave generator with a permanent magnet equipped rotor (4) according to claim 1, characterized in that a thread is introduced into each of the forcing openings (16), in which a forcing screw (18) can be arranged.

4. Decoupling arrangement for a wave generator with a permanent magnet equipped rotor (4) according to claim 1, characterized in that recesses (21) for the flow through of supplied cooling air are arranged in or on the adapter ring (8).

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