TECHNICAL FIELD
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Embodiments of the present disclosure relate to a cycloidal marine propulsion system. Further embodiments relate to a method for accessing a seal arranged between the rotor element and the rotating wheel of a cycloidal marine propulsion system.
BACKGROUND
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Cycloidal marine propulsion systems provide an efficient way to propel marine vessels. Further, cycloidal marine propulsion systems allow for an improved maneuverability of marine vessels. In cycloidal marine propulsion systems, a rotating wheel with rotatable blades attached to the rotating wheel provides thrust. A direction and amount of the thrust may be controlled via a rotating speed of the rotating wheel and via a pitch of the rotatable blades.
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Within the cycloidal marine propulsion system, part of the cycloidal marine propulsion system is arranged within a vessel interior while another part of the cycloidal marine propulsion system is exposed to sea water. A seal is arranged between a static part and a rotating part and ensures that sea water cannot enter the vessel interior and particularly that sea water cannot come into contact with a rotor element of the cycloidal marine propulsion system that is configured to receive a torque for rotating the rotating wheel. Typically, an overall lifetime of the cycloidal marine propulsion system exceeds a lifetime of the seal considerably. Replacing the seal is typically associated with dismounting the rotating wheel of the cycloidal marine propulsion system and is typically performed in a dry dock. However, such a procedure for accessing the seal is costly and time-consuming.
DISCLOSURE OF THE INVENTION
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In the view of the foregoing, the present disclosure is directed to a cycloidal marine propulsion system and a method for accessing of a seal arranged between the rotor element and the rotating wheel of a cycloidal marine propulsion system.
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According to an aspect of the present disclosure, a cycloidal marine propulsion system with a rotating wheel for receiving a plurality of blades, a rotor element configured to receive a torque for rotating the rotating wheel, and an adapter ring is provided. The rotor element comprises a rotor of an electric motor or a gear ring. The adapter ring is separably connected to the rotor element and separably connected to the rotating wheel.
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According to another aspect of the present disclosure, a method for accessing a seal arranged between the rotor element and the rotating wheel of a cycloidal marine propulsion system according to any of the embodiments described herein is provided. The method comprises locking a position of the rotor element; locking a position of the rotating wheel; and accessing the seal.
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According to another aspect of the present disclosure, a rotating wheel locking unit configured for locking the rotating wheel is provided. The rotating wheel locking unit engages a vessel-facing plane of the rotating wheel substantially perpendicular to the rotation axis of the rotating wheel.
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According to some embodiments, the cycloidal marine propulsion system is configured to propel a marine vessel. In particular, the marine vessel may comprise a cycloidal marine propulsion system according to embodiments described herein. The marine vessel comprises seagoing or inland marine vessels. In particular, the marine vessel comprises ships and boats. In some embodiments, the marine vessel comprises ferries, in particular single- and double-ended ferries, cruise ships, water buses, yachts. In some embodiments, the marine vessel comprises offshore energy vessels, in particular service operation vessels (SOVs), cable laying vessels (CLVs), foundation installation vessels (FIVs), offshore construction (OCVs) and support vessels (OSVs), platform supply vessels (PSVs), and anchor-handling tug supply vessels (AHTS). In some embodiments, the marine vessel comprises research and survey vessels or other special purpose vessels. According to some embodiments, the marine vessel comprises merchant ships, in particular for transporting goods.
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The marine vessel comprises a hull. According to some embodiments, the rotating wheel is attached to the hull of the marine vessel, in particular at the bottom of the hull. In some embodiments, the hull comprises a recess. In particular, the recess of the hull is configured for receiving the rotating wheel of the cycloidal marine propulsion system. The rotating wheel typically rotates with respect to the hull of the marine vessel. Typically, the hull defines a vessel interior and a vessel exterior. Space confined by the hull and configured to be isolated from sea water may be defined as the vessel interior. Space outside the hull, and in particular the sea, may be defined as the vessel exterior. Typically, the vessel interior is substantially free of sea water and substantially dry.
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A plurality of electrically driven rotating blades are attached to the rotating wheel. In particular, two, three, four, five, six or more rotating blades may be attached to the rotating wheel. The rotating blades are rotatable with respect to the rotating wheel. In particular, the rotating blades are individually rotatable with respect to the rotating wheel. In other words, each of the plurality of rotating blades can be controlled individually, in particular the pitch of each of the rotating blades can be controlled individually. For each of the rotating blades, the rotating wheel comprises a rotating blade electric motor driving the respective rotating blade. In some embodiments, the pitch of the plurality of rotating blades may be adjusted with no angular restriction. In particular, the plurality of rotating blades may be rotatable by at least 360°. The rotating wheel comprises a plurality of recesses to receive the plurality of electrically driven rotating blades.
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The cycloidal marine propulsion system comprises a rotor element. The rotor element is configured to receive a torque for rotating the rotating wheel. The rotor element is typically arranged in the vessel interior. Typically, the rotor element comprises a rotor of an electric motor or a gear ring. In particular, the cycloidal marine propulsion system may comprise an electric motor driving the cycloidal marine propulsion system and the electric motor comprising a rotor and a stator. The stator is typically fixed in the vessel interior and the rotor is mechanically connected with the rotating wheel to receive and transmit the torque for rotating the rotating wheel. In some embodiments, the rotor element may comprise a gear ring. The gear ring may be mechanically driven by a shaft being driven by an engine of the marine vessel. Typically, the engine of the marine vessel comprises a combustion engine and/or an electric motor.
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The cycloidal marine propulsion system further comprises an adapter ring separably connected to the rotor element and separably connected to the rotating wheel. An element being separably connected to another element may in particular comprise a connection by a screw connection or bolt connection. Typically, elements being separably connected can be separated and reassembled without damage to the elements connected.
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Typically, the adapter ring and the rotor element are arranged such that the adapter ring can be separated from the rotor element in a direction of a vessel interior facing side of the cycloidal marine propulsion system. Typically, the adapter ring may be separated from the rotor element substantially parallel to a rotation axis of the rotating wheel. For a cycloidal marine propulsion system being installed in a marine vessel, the adapter ring may be separated from the rotor element by lifting the adapter ring towards the vessel interior.
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In typical embodiments, the adapter ring connects the rotor element and the rotating wheel. In particular, the adapter ring is configured to carry at least part of the weight of the rotor element, and typically to carry the entire weight of the rotor element. The adapter ring typically transmits a torque of the rotor element to the rotating wheel. Typically, the adapter ring is substantially rotational symmetric along the rotation axis of the rotating wheel and/or along the rotation axis of the rotor element. The adapter ring typically comprises a first section of the adapter ring configured to contact the rotating wheel and a second section of the adapter ring configured to contact a rotating wheel bearing. In typical embodiments, the first section of the adapter ring and the second section of the adapter ring are each circular and the second section is arranged radially inside the first section.
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The adapter ring typically comprises an outer bolt circle for connecting the rotor element with the adapter ring and an inner bolt circle for connecting the rotating wheel with the adapter ring. The inner bolt circle is typically closer to the rotational axis of the rotating wheel than the outer bolt circle. Typically, the outer bolt circle and inner bold circle are substantially rotational symmetric, in particular n-fold rational symmetric, with n being a natural number exceeding 2, exemplarily with n being the number of screw holes in the outer bolt circle or in the inner bolt circle. In typical embodiments, the outer bolt circle comprises at least 8, at least 16, at least 24, at least 48 or at least 72 screw holes. In typical embodiments, the inner bolt circle comprises at least 8, at least 16, at least 24, at least 48 or at least 72 screw holes. Typically, each of the screw holes of the inner bolt circle and/or of the outer bolt circle has a diameter of at least 2 cm, at least 5 cm or at least 10 cm. In typical embodiments, each of the screw holes of the inner bolt circle and/or of the outer bolt circle has a diameter of at least 2 cm and of at most 5 cm.
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In typical embodiments, the orientation of the inner bolt circle is substantially parallel to the rotation axis of the rotating wheel. In typical embodiments, the orientation of the outer bolt circle is substantially parallel to the rotation axis of the rotating wheel. The orientation of the inner bolt circle and of the outer bolt circle may be defined along a symmetry axis of the respective bolt circle. In some embodiments, the orientation of the inner bolt circle and of the outer bolt circle may be defined along an axis of the screw holes of the respective circles; in other words, the screw holes of the inner bolt circle and/or of the outer bolt circle may be substantially parallel to the rotation axis of the rotating wheel. Two axes may be considered as substantially parallel for an angle between both axis not exceeding 2°, not exceeding 5°, or not exceeding 10°.
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Typically, the inner bolt circle and/or the outer bolt circle are accessible from a vessel interior facing side of the adapter ring in a mounted state of the cycloidal marine propulsion system. In particular, for a cycloidal marine propulsion system being mounted in the marine vessel, the inner bolt circle and/or the outer bolt circle are accessible from the vessel interior. Exemplarily, the cycloidal marine propulsion system may comprise a maintenance hatch on a vessel interior facing surface of the cycloidal marine propulsion system allowing a technician to access the adapter ring and particularly the inner bolt circle and/or the outer bolt circle. Typically, the cycloidal marine propulsion system may be configured to allow the technician to enter the rotating wheel, particularly in a central space of the rotating wheel. In typical embodiments, the inner bolt circle and/or the outer bolt circle may be opened from the vessel interior facing side of the adapter ring.
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In typical embodiments, the cycloidal marine propulsion system comprises a seal, in particular a main seal, arranged between the rotor element and the rotating wheel. The seal is typically configured to separate a vessel interior part of the cycloidal marine propulsion system and a vessel exterior part of the cycloidal marine propulsion system. In particular, the seal is configured to avoid water entering the vessel interior part of the cycloidal marine propulsion system from the vessel exterior. In typical embodiments, the seal is made of a rubber material or a plastic material, exemplarily polyurethane (PU, PUR), PTFE, or PEEK.
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Typically, the seal is accessible by lifting the adapter ring along the rotation axis of the rotating wheel without lifting the rotor element. In particular, no movement, and in particular no vertical movement or lifting, of the rotor element is required to access the seal. Particularly, no lifting of the rotor element along the rotation axis of the rotating wheel is required. Typically, the adapter ring is lifted by at least 200 mm, at least 300 mm, at least 350 mm or at least 400 mm. In some embodiments, the adapter ring is lifted by at most 0.5 m or at most 1 m. Avoiding a movement of the rotor element to access the seal may advantageously reduce the weight of components to be moved during an accessing of the seal and particular during a seal replacement. Thereby, technical tools required for accessing or replacing the seal may be simplified; exemplarily, a means of lifting, particularly a crane, may require considerably less lifting force.
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In some embodiments, the adapter ring may comprise a plurality of adapter lifting rings. The plurality of adapter lifting rings is typically configured to carry the weight of the adapter ring when being lifted. The plurality of adapter lifting rings may be permanently attached to the adapter ring. Typically, the plurality of adapter lifting rings may be inserted in and/or attached to the inner bolt circle or the outer bolt circle or between the inner bolt circle and the outer bolt circle. In some embodiments, the plurality of adapter lifting rings may be attached on a, particularly cylindrical, surface inside the inner bolt circle or on a, particularly cylindrical, surface outside the outer bolt circle. The adapter ring may be lifted to an upper, in other words vessel interior facing, surface of the cycloidal marine propulsion system. In some embodiments, the maintenance hatch of the cycloidal marine propulsion system may have a diameter substantially the same as the adapter ring diameter or exceeding the adapter ring diameter. The adapter ring may be lifted at a position of the maintenance hatch and may be locked in a position of a maintenance hatch cover. In some embodiments, the adapter ring may be locked in a lifted position using a maintenance hatch bolt circle. In particular, an adapter ring locking element may connect the outer bolt circle of the adapter ring and the maintenance hatch bolt circle.
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Subsequent to lifting the adapter ring, a main bearing outer bolt circle is exposed and accessible, particularly from the vessel interior. The main bearing of the rotating wheel typically comprises the main bearing outer bolt circle and a main bearing inner bolt circle. The main bearing inner bolt circle typically overlaps with the inner bolt circle of the adapter ring. In particular, when the cycloidal marine propulsion system is completely assembled, the screw holes of the main bearing inner bolt circle and of the inner bolt circle of the adapter ring typically overlap. Thus, the adapter ring may be connected to the rotating wheel via the inner bolt circle of the adapter ring.
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The main bearing inner bolt circle typically is configured for connecting a main bearing of the rotating wheel to the rotating wheel. The main bearing outer bolt circle typically is configured for connecting a main bearing outer ring to a main bearing housing arranged on a static side of cycloidal propulsion unit. The main bearing typically supports the rotating wheel in the vessel hull. Typically, the main bearing comprises the main bearing housing. In some embodiments, the main bearing, and particularly the main bearing housing, is configured to be liftable along a rotation axis of the rotating wheel, particularly in the direction of the vehicle interior. The main bearing, and particularly the main bearing housing, may comprise a plurality of bearing lifting rings. The plurality of bearing lifting rings may be permanently attached to the main bearing, and particularly to the main bearing inner ring and/or to the main bearing outer ring.
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The main bearing may be lifted up to the adapter ring. Typically, and particularly after lifting the main bearing, the main bearing may be locked to an upper position. In particular, the main bearing may be connected or locked to the adapter ring. In effect, the main bearing may exemplarily be supported by the maintenance hatch bolt circle. Typically, the main bearing is locked to the upper position via stud bolts or threaded bolts and nuts. Exemplarily, the main bearing is connected to the adapter ring via the inner bolt circle. A plurality of stud bolts and/or threaded bolts is inserted into a plurality of the screw holes. On each end of the plurality of stud bolts and/or threaded bolts, a nut is attached and fastened.
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In some embodiments, the main bearing may comprise at least one bearing locking screw thread on a vessel-facing side of the main bearing, and particularly of the main bearing inner ring or of the main bearing outer ring. The adapter plate may comprise a bearing access bolt ring, particularly configured to access the at least one bearing locking screw thread. Typically, the bearing access bolt ring and the at least one bearing locking screw thread are at least partially overlapping. In some embodiments, the bearing access bolt ring is arranged radially between the inner bolt ring and the outer bolt ring. To lock the main bearing in the upper position, a bearing locking screw may be inserted from the vessel interior. In some embodiments, a screw, a stud bolt or a threaded bolt may be inserted into the at least one locking screw thread and a nut may be attached and fastened. The main bearing may be locked to the upper position either via the inner bolt circle or via the at least one locking screw thread. In some embodiments, the main bearing may be locked both via the inner bolt circle and the at least one locking screw thread, exemplarily to ensure redundancy.
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In some embodiments, a clamp ring is arranged between the seal and the main bearing. Prior to accessing the seal, the clamp ring is typically lifted towards the vessel interior and particularly attached to the main bearing. The clamp ring may be attached to the main bearing via a clamp locking bolt ring. Typically, the main bearing housing and the adapter plate each comprise the clamp locking bolt ring to lock the clamp ring. Typically, the clamp ring comprises at least one clamp ring screw thread. A screw, a stud bolt or a threaded bolt may be inserted into the at least one clamp ring screw thread and a nut may be attached and fastened.
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The exposed seal may be accessed subsequent to the clamp ring being lifted. In particular, the exposed seal may be accessed from the vessel interior. In typical embodiments, a technician can access the cycloidal marine propulsion system via the maintenance hatch from the vessel interior. In particular, the technician can typically climb into the cycloidal marine propulsion system and access the seal directly without any additional tools. Typically, the seal may be removed, and optionally inspected. In some embodiments, after removal of the seal, a sealing housing and a seal liner, particularly made from a cobalt-chromium alloy, from a chrome steel, exemplarily a martensitic stainless steel, or from a ceramic, may be inspected and potentially maintained or replaced. In some embodiments, the seal may be lifted by at least 200 mm, at least 300 mm or at least 350 mm and/or by at most 400 mm, at most 500 mm or at most 600 mm.
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Subsequent to the seal being removed, a new seal is typically installed. Typically, the new seal is inserted into the cycloidal marine propulsion system in a plurality of seal parts, or with an opening. Typically, installing the new seal comprises a bonding of the new seal within the cycloidal marine propulsion system. In other words, the seal is bonded on site. Bonding the seal on side may advantageously allow to avoid disassembling and subsequent reassembling of cables and pipes in the interior of the cycloidal marine propulsion system.
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In some embodiments, in particular alternatively to a seal bonding at site, cables and pipes arranged from a central portion of the cycloidal marine propulsion system towards a water facing side of the seal or the bottom part of the cycloidal marine propulsion system, exemplarily towards sensors or blades of the cycloidal marine propulsion system, may be removed or disconnected. This may advantageously allow to install the new seal without a bonding step.
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Typically, after positioning and installing the new seal, the seal may be tested, in particular pressure tested. To test the new seal, the clamp ring is typically reinstalled by lowering the clamp ring onto the new seal. Testing whether the new seal is set properly prior to reinstalling the main bearing advantageously allows to check the sealing before installing the main bearing, therefore particularly reducing unnecessary work in case a leaking seal is noticed during testing.
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Typically, after installing the new seal, the cycloidal marine propulsion system is re-assembled. In particular, the cycloidal marine propulsion system is reassembled in a reverse order. Typically, the clamp ring is loosened from the main bearing, in particular by disassembling the nuts. Subsequently, the main bearing may be disconnected from the adapter ring, particularly by removing the plurality of stud bolts and/or threaded bolts and the nuts. After the main bearing has been arranged in position, the adapter ring may be reassembled. In particular, the adapter ring locking element may be removed and the adapter ring may be re-positioned on the main bearing and the rotor element. Typically, the adapter ring is re-connected to the rotor element and the rotating wheel; in particular via the outer bolt circle and the inner bolt circle. With the cycloidal marine propulsion system being reassembled, the maintenance hatch of the cycloidal marine propulsion system may be closed.
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Accessing a seal between the rotor element and the rotating wheel of a cycloidal marine propulsion system via the vessel interior, as exemplarily described above, and particularly using a cycloidal marine propulsion system with an adapter ring advantageously allows to access and particularly to replace the seal while the marine vessel is in water. Particularly, a dry dock is not required.
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In some embodiments, prior to accessing the seal, a position of the rotor element is being locked. In particular, the position of the rotor may be locked using at least one rotor element locking mechanism. Typically, the rotor element locking mechanism comprises at least one rotor transportation locking piece. Locking the position of the rotor element may particularly comprise blocking a rotational degree of freedom of the rotor element. Typically, a radial position and/or an axial position of the rotor is locked. In some embodiments, the rotor element locking mechanism comprises a plurality of rotor transportation locking pieces. In particular, the rotor element locking mechanism comprises at least one rotor transportation locking piece for each dimension or degree of freedom of the rotor element to be locked. In typical embodiments, the rotor element locking mechanism comprises at least two rotor transportation locking pieces and preferably at least three rotor transportation locking pieces. Typically, the rotor transportation locking piece may comprise a bolt, a screw, or a locking pin. Typically, the rotor transportation locking piece comprises a thread, particularly embedded on a rotor element side of the cycloidal marine propulsion system. In some embodiments, the rotor transportation locking piece comprises a plurality of bolts, screws, locking pins or threads. Typically, a plurality of locking bolts are passing through a top cover of the cycloidal marine propulsion system and are typically configured to carry the weight of the rotor element. Typically, a plurality of rotor transportation locking pieces are being employed. The rotor transportation locking piece may be applied from an outside of the cycloidal marine propulsion system and particularly from the vessel interior. The rotor transportation locking piece is configured to mechanically connect a fixed portion of the cycloidal marine propulsion system and the rotor element. Typically, the rotor transportation locking piece is arranged to lock the position of the rotor element in a defined position. In particular, the rotor element may be locked in a position where parts of the rotor element, exemplarily openings in the rotor element, are overlapping structures, and particularly fixed, non-rotating structures, of the cycloidal marine propulsion system, exemplarily at least one opening for accessing the rotor element from a vessel interior.
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In some embodiments, the rotor element locking mechanism comprises a locking sensor for sensing whether the rotor element is locked. The locking sensor may be connected to a lock of the maintenance hatch or of hatches for accessing components of the cycloidal marine propulsion system, particularly for ensuring that the rotor element is locked before an access to the interior of the cycloidal marine propulsion system is enabled. The rotor element locking mechanism may advantageously allow a safe access to the cycloidal marine propulsion system.
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In some embodiments, the cycloidal marine propulsion system comprises a rotating wheel locking unit configured for locking the rotating wheel. In particular, the rotating wheel locking unit is configured to carry at least 50%, at least 70% or at least 90% of a weight of the rotating wheel. Particularly, the rotating wheel locking unit is configured to carry the entire weight of the rotating wheel. Typically, the rotating wheel locking unit engages a vessel-facing plane of the rotating wheel substantially perpendicular to the rotation axis of the rotating wheel. Typically, the rotating wheel locking unit comprises a plurality of subunits, particularly at least 2, at least 3, at least 5 or at least 8 subunits. Particularly, the subunits of the rotating wheel locking unit may be arranged substantially equally-spaced in a radial direction. In other words, the subunits may be evenly arranged. In some embodiments, positions of the subunits may be arranged with a radial symmetry about the rotation axis, particularly an n-fold radial symmetry.
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In some embodiments, the rotating wheel locking unit engages the vessel-facing plane of the rotating wheel at a radial distance to the rotation axis larger than a radial distance of a rotating wheel bearing to the rotation axis and smaller than an outer radius of the rotating wheel. In other words, the rotating wheel locking unit engages the vessel-facing plane of the rotating wheel radially between the rotating wheel bearing and the outer radius of the rotating wheel.
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Typically, the rotating wheel locking unit, and particularly each subunit, comprises a lifting screw thread in the rotating wheel. An axis of the screw thread is typically substantially parallel to the rotation axis of the rotating wheel. In particular, the axis of the screw thread has an angle of at most 2°, at most 5° or at most 10° with respect to the rotation axis. Typically, the rotating wheel locking unit comprises at least 3, at least 5 or at least 8 lifting screw threads, and particularly exactly 3 lifting screw threads. Typically, each subunit comprises at least one lifting screw thread. The rotating wheel may be locked using the rotating wheel locking unit. In particular, lifting screws may be inserted in the lifting screw threads. The lifting screws may be supported from a vessel facing side of the cycloidal marine propulsion system, particularly with the lifting screws passing through the rotor element. In some embodiments, the lifting screws may be supported from an upper (or vessel facing) end of a shaft in which the rotating wheel is arranged. In some embodiments, the rotating wheel locking unit may engage the rotating wheel from a side end of the shaft, particularly from a wall of the shaft substantially parallel to the rotation axis of the rotating wheel.
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In some embodiments, a rotating wheel locking unit lifting ring may be inserted in the lifting screw thread and the rotating wheel may be supported by a lifting belt, a round sling or a lifting chain.
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In some embodiments, the rotating wheel locking unit comprises an opening for engaging the rotating wheel locking unit from a vessel interior facing side of the cycloidal marine propulsion system through the rotor element. In particular, the opening may extend at least 20 cm in a first direction perpendicular to the rotation axis of the rotating wheel and at least 20 cm in a second direction perpendicular to the rotation axis of the rotating wheel and perpendicular to the first direction. Thereby, accessing the rotating wheel locking unit with tools may be enabled advantageously.
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Typically, the cycloidal wheel propulsion system comprises a water tight hatch for inserting and/or mounting the rotating wheel locking unit from a vessel interior facing side of the cycloidal marine propulsion system. In particular, the water tight hatch is arranged substantially at a radial position of rotating blades of the cycloidal marine propulsion system. The water tight hatch is typically arranged on a water-facing side of the rotor element. In some embodiments, the water tight hatch may also be opened to access and/or maintain the cycloidal marine propulsion system and particularly blades of the cycloidal marine propulsion system.
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In some embodiments, prior to locking the rotating wheel, and particularly to inserting and/or mounting the rotating wheel locking unit, water has to be removed from the vicinity of the cycloidal marine propulsion system. In particular, prior to opening the water tight hatches, preparations have to be taken to avoid water flowing into the cycloidal marine propulsion system. In some embodiments and for some marine vessels, the marine vessel may be trimmed such that no water is present between the upper end of the shaft and the rotating wheel. In some embodiments, an inflatable annular seal may be installed to seal the cycloidal marine propulsion system against sea water. In particular, a diver may install the inflatable annular seal or another type of temporary seal at a sea side facing end of the cycloidal marine propulsion system between the hull of the marine vessel and the rotating wheel. The inflatable annular seal, which may also be described as tubular sealing, is pressurized with air to close and to seal the gap between the hull and the rotating wheel. Installing the inflatable annular seal may comprise removing flow cover plates and cleaning at least part of the surface of the cycloidal marine propulsion system. Subsequently to installing the inflatable annular seal, a drain plug and a breathing plug may be opened and the space between the hull and the cycloidal marine propulsion system may be emptied from water.
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A method of accessing a seal arranged between the rotor element and the rotating wheel of a cycloidal marine propulsion system, and particularly the cycloidal marine propulsion system according any of the embodiments described herein, comprises locking a position of the rotor element; locking a position of the rotating wheel; and accessing the seal. The position of the rotor element may particularly be locked using the rotor element locking mechanism described herein. The position of the rotating wheel may particularly be locked using the rotating wheel locking unit described herein.
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In some embodiments, the method of accessing a seal further comprises lifting the adapter ring and a rotating wheel bearing along the rotation axis of the rotating wheel in a direction of a vessel interior facing side of the cycloidal marine propulsion system such that the seal is exposed. Thereby, the seal may be accessed from the vessel interior. Ship yard infrastructure is not required, which may allow savings in both time and costs. The method may advantageously be conducted offshore, particularly in calm weather conditions.
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In some embodiments, the method of accessing a seal further comprises removing the rotating wheel along the rotation axis of the rotating wheel in a direction opposite to a vessel interior facing side of the cycloidal marine propulsion system such that the seal is exposed. Accessing the seal by removing the rotating wheel in a direction opposite to the vessel interior may require using a dry dock or similar ship yard infrastructure. However, particularly for marine vessels being in a dry dock for further maintenance, accessing the seal by removing the rotating wheel in a direction opposite to the vessel interior may be more efficient.
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Embodiments of the present disclosure provide cycloidal marine propulsion systems with an improved accessibility of an interior of the cycloidal marine propulsion system. In particular, accessing a seal arranged between the rotor element and the rotating wheel of the cycloidal marine propulsion system may be facilitated. The interior of the cycloidal marine propulsion system may be accessed and exemplarily the seal may be assessed and/or replaced without the need for ship yard infrastructure such as a dry dock. The interior of the cycloidal marine propulsion system may be accessed by lifting select elements of the cycloidal marine propulsion system with only a limited weight. Overall, the cycloidal marine propulsion systems and methods for accessing a seal arranged between the rotor element and the rotating wheel of the cycloidal marine propulsion system described herein allow to reduce maintenance cost and time.
BRIEF DESCRIPTION OF THE DRAWINGS
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The accompanying drawings relate to embodiments of the disclosure and are described in the following:
- Fig. 1
- schematically illustrates a cycloidal marine propulsion system according to the embodiments described herein;
- Fig.2
- schematically illustrates a detail of the cycloidal marine propulsion system of Fig. 1;
- Fig.3a
- schematically illustrates a cycloidal marine propulsion system with a rotating wheel locking unit according to the embodiments described herein;
- Fig.3b
- schematically illustrates a cycloidal marine propulsion system with a rotating wheel being locked using the rotating wheel locking unit according to Fig. 3a;
- Fig.4
- schematically illustrates the cycloidal marine propulsion system of Fig. 1 with an adapter ring being lifted;
- Fig. 5
- schematically illustrates a method for accessing a seal arranged between a rotor element and a rotating wheel of a cycloidal marine propulsion system according to embodiments described herein.
DETAILED DESCRIPTION OF EMBODIMENTS
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Reference will now be made in detail to the various embodiments of the disclosure, one or more examples of which are illustrated in the figures. Generally, only the differences with respect to individual embodiments are described. Each example is provided by way of explanation of the disclosure and is not meant as a limitation of the disclosure. Further, features illustrated or described as part of one embodiment can be used on or in conjunction with other embodiments to yield a further embodiment. It is intended that the description includes such modifications and variations. In the figures, elements may be depicted with exaggerated dimensions to improve the comprehensibility of the detailed description of embodiments. In particular, relations of lengths and widths of components shown may be distorted. Further, some elements may be depicted with enlarged dimensions while other elements in the same figure are depicted, relatively, with reduced dimensions.
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Fig. 1 schematically illustrates a cycloidal marine propulsion system 100 according to embodiments described herein. The cycloidal marine propulsion system 100 comprises a rotating wheel 20 for receiving a plurality of blades 30a, 30b, 30c. In Fig. 1, only three blades 30a, 30b, 30c are visible. In Fig. 1, the blades 30a, 30b, 30c are only partly shown, with their lower end not being shown. The cycloidal marine propulsion system 100 further comprises a rotor element 40 configured to receive a torque for rotating the rotating wheel 20. In the embodiment of Fig. 1, the rotor element 40 is a rotor of an electric motor. The rotor element 40 comprises rotor poles 41. The electric motor of the cycloidal marine propulsion system 100 comprises the rotor element 40 with the rotor poles 41 and a stator 42. The cycloidal marine propulsion system 100 further comprises an adapter ring 10. The adapter ring 10 is separably connected to the rotor element 40 and the adapter ring 10 is separably connected to the rotating wheel 20. The rotating wheel 20 of the cycloidal marine propulsion system 100 is configured to rotate about a rotation axis 50. The cycloidal marine propulsion system 100, and particularly the adapter ring 10, is rotationally symmetric with respect to the rotation axis 50.
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The adapter ring 10 and the rotor element 40 are arranged such that the adapter ring 10 can be separated from the rotor element 40 in a direction of a vessel interior facing side of the cycloidal marine propulsion system 100. In Fig. 1-4, the vessel interior is arranged on the upper end of the respective figure and a water (or sea floor) facing end of the cycloidal marine propulsion system 100 is arranged on a lower end of the respective figure. The adapter ring 10 and the rotor element 40 are arranged such that the adapter ring 10 can be separated from the rotor element 40 substantially parallel to the rotation axis 50. In particular, the adapter ring 10 can be lifted towards the vessel interior. The cycloidal marine propulsion system 100 comprises a seal 1. The seal 1 is configured to seal an interior facing side of the cycloidal marine propulsion system 100 against an exterior facing side of the cycloidal marine propulsion system 100, and in particular against sea water. The seal 1 is arranged between the rotor element 40 and the rotating wheel 20. The seal 1 can be accessed by lifting the adapter ring 10 and the main bearing 22 along the rotation axis 50 without lifting the rotor element 40. In other words, for accessing the seal 1, the rotor element 40 can remain in its place. For accessing the seal 1, the rotating wheel 20 can remain in its place.
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The cycloidal marine propulsion system 100 comprises a rotating wheel bearing 22. The rotating wheel bearing 22 supports the rotating wheel 20. The rotating wheel bearing 22 allows a rotation of the rotating wheel with respect to a hull of a marine vessel propelled by the cycloidal marine propulsion system 100. The rotating wheel bearing 22 is arranged between the adapter ring 10 and the rotating wheel 20. In particular, the rotating wheel bearing 22 is arranged below the adapter ring 10.
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The cycloidal marine propulsion system 100 comprises a maintenance hatch 15 on the vessel interior facing side of the cycloidal marine propulsion system 100. The maintenance hatch 15 is configured to allow a service technician to enter the cycloidal marine propulsion system 100. The maintenance hatch 15 is typically configured to allow access of a technician and/or tools, exemplarily of cranes or lifting devices, into cycloidal marine propulsion system 100. Exemplarily, the adapter ring 10 or the rotating wheel bearing 22 may be accessed.
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In Fig. 2, a detail of the cycloidal marine propulsion system 100, as depicted in Fig. 1, is shown. The section of the cycloidal marine propulsion system 100 shown in Fig. 2 is highlighted in Fig. 1 as "A". In particular, Fig. 2 shows the adapter ring 10 in more detail. The adapter ring 10 connects the rotor element 40 and the rotating wheel 20. The adapter ring 10 comprises an outer bolt circle 12 and an inner bolt circle 13. The outer bolt circle 12 is arranged at a larger distance to the rotation axis 50 than the inner bolt circle 13. The outer bolt circle 12 is configured to connect the rotor element 40 with the adapter ring 10. In particular, a section of the adapter ring 10 overlays a section of the rotor element 40. In the cross-sectional view as provided in the Fig. 1-4, a step-like contour of the adapter ring 10 can be seen. In particular, a lower surface of the adapter ring 10 comprises a first surface for contacting and/or connecting the rotating wheel 20 and a second surface for contacting and/or connecting the rotor element 40. The second surface is closer to the vessel interior than the first surface. The inner bolt circle 13 is configured to connect the adapter ring 10 with the rotating wheel 20. A screw or bolt inserted into the inner bolt circle 13 or outer bolt circle 12 provides a mechanical connection to the rotating wheel 20 or the rotor element 40, respectively.
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Fig. 3a schematically illustrates a cycloidal marine propulsion system with a rotating wheel locking unit 300. In Fig. 3a, a similar section of the cycloidal marine propulsion system 100 as shown in Fig. 2 and as marked in Fig. 1 by "A", is depicted. The rotating wheel locking unit 300 is configured for locking the rotating wheel 20. The rotating wheel locking unit 300 can support the weight of the rotating wheel 20. The rotating wheel locking unit 300 engages a vessel-facing plane 310 of the rotating wheel 20 at a lifting point 311. The vessel-facing plane 310 is substantially perpendicular to the rotation axis 50 of the rotating wheel 20. The wheel locking unit 300 comprises a lifting screw thread 320 in the rotating wheel 20 and particularly in the vessel-facing plane 310 of the rotating wheel 20. The rotating wheel locking unit 300 engages the vessel-facing plane 310 of the rotating wheel 20 at a radial distance to the rotation axis 50 larger than a radial distance of a rotating wheel bearing 22 to the rotation axis 50 and smaller than an outer radius of the rotating wheel 20. Particularly, the lifting screw thread 320 is arranged radially between the outer radius of the rotating wheel 20 and the rotating wheel bearing 22. The lifting screw thread 320 is arranged substantially parallel to the rotation axis 50 of the rotating wheel 20.
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The rotating wheel locking unit 300 comprises an opening 315 for engaging the rotating wheel locking unit 300 from a vessel interior facing side of the cycloidal marine propulsion system 100. The opening 315 at least partially overlaps the lifting screw thread 320 horizontally. Typically, the rotor element 40 comprises at least one, and preferably three or more, rotor element opening 340 that at least partially overlaps with the opening 315. The rotor element opening 340 is configured to provide access to the water tight hatch 325 and the lifting point 311 from the opening 315 through the rotor element 40. The rotating wheel locking unit 300 comprises a water tight hatch 325 for inserting and/or mounting the rotating wheel locking unit 300 from a vessel interior facing side of the cycloidal marine propulsion system 100. Typically, the rotating wheel locking unit 300 comprises three or more water tight hatches 325, with only one water tight hatch 325 being shown in Fig. 3a. The water tight hatch 325 at least partially overlaps with the opening 315. The water tight hatch 325 at least partially overlaps with the rotor element opening 340.
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In Fig. 3b, the rotating wheel locking unit 300 of Fig. 3a is used for locking the rotating wheel 20. In Fig. 3b, the water tight hatch has been removed and a lifting screw 324 engages the vessel-facing plane 310 of the rotating wheel 20 at the lifting point 311. Particularly, the lifting screw 324 is screwed into the lifting screw thread 320.
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In Fig. 4, the adapter ring 10 of the cycloidal marine propulsion system 100 has been lifted. The rotating wheel bearing 22 is exposed and accessible. The adapter ring 10 is attached to a vessel interior facing side of the cycloidal marine propulsion system 100, in particular to a housing of the cycloidal marine propulsion system 100. In particular, an adapter ring locking element 410 connects the adapter ring 10, particularly via the outer bolt circle 12 to the housing of the cycloidal marine propulsion system 100. In Fig.4, the main bearing 22 is accessible and can be dismounted from inside the cycloidal marine propulsion system 100 and can be lifted against adapter ring 10. Once the main bearing 22 is lifted against the adapter ring 10, the seal 1 may be accessed and be replaced from inside the cycloidal marine propulsion system 100.
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In Fig. 5, a method 500 for accessing a seal arranged between a rotor element and a rotating wheel of a cycloidal marine propulsion system is shown. The method 500 comprises locking a position of the rotor element 510, locking a position of the rotating wheel 520, and accessing the seal 530.