Gyroscopic stabilizer assembly

Abstract

The present disclosure relates to a gyrostabilizer assembly (1) for a marine vessel, comprising: a housing (13) defining a chamber (12) for supporting an at least partial vacuum; a flywheel (33) mounted within the chamber (12) for rotation under partial vacuum about an axis of rotation (Z); a flywheel shaft (34) on which the flywheel (33) is mounted in the housing (13) so as to rotate the flywheel (33) about an axis of rotation (Z), the flywheel shaft (34) being rotatably supported by a first swivel bearing (21) at one end region of the shaft (34) and a second swivel bearing (31) at the opposite end region of the shaft (34); and a lubrication system (10) comprising a lubricant circuit (71, 79, 50, 51) for circulating liquid lubricant (O) from a lubricant sump or reservoir tank (70) to the first bearing (21) and the second bearing (31). A reservoir tank (70) is arranged in or on the housing (13) to collect lubricant from the bearings (21, 31) under the action of gravity, and the first bearing (21) and the second bearing (31) are arranged in the housing (13) to operate under partial vacuum. The lubrication system (10) comprises a rotating disk pump (60) disposed in the sump or reservoir tank (70) and coupled to and driven by the flywheel shaft (34) for circulating lubricant to the first bearing (21) and the second bearing (31) via a lubricant circuit. The present disclosure also relates to a vehicle, in particular a vessel, comprising the gyrostabilizer assembly (1).

Description

Technical Field

[0001] The present disclosure relates to a gyro stabilizer assembly, and more particularly to a gyro stabilizer assembly having an improved bearing lubrication system.

[0002] The gyro stabilizer assembly of the present disclosure is generally designed for use on a ship, and it will be convenient to describe it in this exemplary context. However, it should be understood that the gyro stabilizer assembly of the present disclosure is not limited to this particular application and can be designed for many other applications, such as other fixed and floating structures, other vehicles, lifting systems, and / or camera mounts. Background Art

[0003] The discussion of background art in this specification, including reference to any document, should in no way be regarded as an admission that such background art is known in Australia or any other country or forms part of the common general knowledge in the art.

[0004] The structure and operation of marine gyro stabilizer assemblies are generally well understood, and these devices are increasingly being adopted in commercial and recreational ships. A gyro stabilizer assembly typically includes a rotating flywheel mounted in a gimbal frame that allows rotational freedom, and the gimbal frame is rigidly mounted within the ship. The particular way in which the flywheel is constrained in rotational motion allows the angular momentum of the rotating flywheel to combine with the precession oscillations of the flywheel to produce a large torque that varies over time to directly counteract the dynamic roll motion of the ship caused by wind and / or waves. In the absence of any intervention, the ship roll motion combines with the flywheel angular momentum to cause an oscillatory precession motion. This then combines with the angular momentum to produce a stabilizing torque that directly resists the undesired rotational motion of the ship (e.g., the wave-induced roll motion). By arranging the gimbal in a particular way, a roll stabilization device is produced using the physics of naturally occurring gyroscopic dynamics, which therefore does not require further intervention to operate. An example of a marine gyro stabilizer assembly is described in the applicant's Australian Patent Application No. AU 2017216483A1, the content of which is incorporated herein by reference in its entirety.

[0005] Due to the high speed of the outer edge of the flywheel in the gyro stabilizer, the gimbal frame typically includes a chamber that surrounds the flywheel, and the chamber is evacuated so that the flywheel can rotate within a vacuum. This reduces the aerodynamic drag on the flywheel, thereby reducing the power required to maintain the flywheel speed (rpm). It also reduces the heat generated on the rotating flywheel rim by air resistance, which in turn improves efficiency. The rotary bearings used to position and hold the flywheel about the axis of rotation are subject to high loads and high rotational speeds, which also generate heat and noise. The rotary bearings and the rotary motor are typically located within the vacuum chamber to avoid problems associated with sealing the vacuum chamber where the rotating shaft exits the vacuum chamber. However, locating the rotary bearings inside the vacuum chamber can make it difficult to lubricate and cool these bearings. Cooling the interior of the rotary bearings and the flywheel shaft can be particularly difficult because these rotary bearings and flywheel shafts are rotating and are not easily cooled by contact with a coolant jacket.

[0006] The co-pending Australian patent application AU 2017216483A1 describes an arrangement having an oil lubrication system for lubricating and cooling the bearings, with which the flow rate of the oil flowing to the bearings can be selected to provide lubrication and exchange the heat generated by the bearings into the oil. The oil lubrication system is ideal for reducing noise, extending the bearing life, and the ability to dissipate heat from the interior of the bearings. In this system, the oil is drawn from an oil sump by one or more scavenge pumps. To allow the scavenge pumps to operate, this arrangement isolates the upper bearing chamber and the lower bearing chamber from the vacuum chamber, which encloses the flywheel through a rotary shaft seal on the flywheel shaft. One seal is located below the upper bearing chamber and another seal is located above the lower bearing chamber, and the upper bearing chamber and the lower bearing chamber are connected together by a discharge pipeline therebetween. With this arrangement, the flywheel can rotate at a sufficiently low pressure in a partial vacuum or near-vacuum state such that the air resistance is significantly reduced or eliminated, while the bearing housings (which are connected by a manifold such that they operate at the same pressure) can operate at a sufficiently high pressure so that the scavenge pumps can effectively pump the oil to the rotary bearings.

[0007] However, a disadvantage of the arrangement described in AU 2017216483A1 is that it requires a dual vacuum pressure management system for the vacuum chamber and the bearing chamber, and the rotary shaft seal components are subject to rotational resistance from the high contact surface speed, which results in wear and the associated costs of maintenance and / or subsequent replacement, as well as the need for higher power to maintain the desired flywheel speed (rpm).

[0008] To address these issues, the present applicant has developed a new gyro stabilizer device that does not require a rotary shaft seal that separates or isolates the working pressure of the rotary bearing from the flywheel chamber. An example of such a gyro stabilizer assembly is described in the applicant's international patent application PCT / AU2021 / 050197, published as WO 2021 / 174315A1, the content of which is incorporated herein by reference in its entirety. The advantage of this new arrangement is that it does not require a dual vacuum pressure management system and simplifies the arrangement by reducing the number of components and potential failure points, making the gyro stabilizer assembly more reliable and robust. However, it has been found that bearing lubrication problems, particularly lubricating oil circulation problems, can typically be encountered when the working pressure of the flywheel chamber is a rough vacuum of about 0.1 bar or less (absolute pressure). Unless otherwise stated, the pressure values presented herein are absolute pressure values.

[0009] Accordingly, it is desirable to provide a new gyro stabilizer device that substantially overcomes or ameliorates one or more of the above disadvantages. In this regard, it is desirable to provide a new gyro stabilizer assembly having a lubrication system that can reliably lubricate and cool the bearings when operating in a rough vacuum or partial vacuum. Summary of the Invention

[0010] According to a broad aspect, the present disclosure provides a gyro stabilizer assembly comprising:

[0011] a housing that defines a chamber for supporting a working pressure;

[0012] a flywheel mounted within the chamber for rotation about a rotational axis under the working pressure;

[0013] a flywheel shaft on which the flywheel is mounted within the housing, the flywheel shaft being supported by a first rotary bearing and a second rotary bearing located at opposite end regions of the flywheel shaft to enable the flywheel to rotate about the rotational axis, wherein the first rotary bearing and the second rotary bearing are arranged within the housing for use under the working pressure; and

[0014] a bearing lubrication system including a lubricant circuit for circulating a liquid lubricant from a lubricant reservoir or sump to the first rotary bearing and the second rotary bearing, the lubricant reservoir or sump being positioned or arranged to collect the liquid lubricant from the first rotary bearing and the second rotary bearing under the influence of gravity, wherein the bearing lubrication system includes a pump disposed within the reservoir or sump, the pump being coupled to the flywheel shaft and driven by the flywheel shaft to circulate the lubricant within the lubricant circuit.

[0015] In one embodiment, the pump includes a rotary disk pump, which is a centrifugal pump having an impeller that includes at least one substantially flat disk, preferably two (or more) substantially flat disks, which are mounted relative to each other in a spaced-apart, generally parallel arrangement. The impeller typically has no guide vanes and, when rotated, utilizes the principles of boundary layer and viscous drag to push a liquid lubricant (e.g., oil) along a lubricant circuit from a reservoir or sump. Since the impeller of the rotary disk pump is preferably designed without guide vanes, it can rotate at extremely high speeds in a substantially laminar flow of the lubricant without generating significant vibration or cavitation. The rotary disk pump is preferably a closed rotary disk pump. It preferably includes a first solid (such as flat or planar) disk, which is mounted to at least a second axially aligned (such as flat or planar) annular disk in a uniformly spaced relationship, and the outer diameter of the annular disk is substantially the same as the outer diameter of the first disk. The central opening in the annular disk is a central flow path or channel that allows oil to enter the impeller and the space between the disks. The pump or "pump assembly" in the reservoir or sump can be considered a "return pump" for returning the lubricant from the sump to the lubricant circuit.

[0016] In an embodiment of the present disclosure, the rotary disk pump includes a plurality of axially aligned annular disks, preferably having substantially the same outer diameter as the first disk. The plurality of annular disks can be mounted in a stacked array above the first disk, preferably spaced apart from each other and / or from the first disk substantially uniformly. The central opening in each annular disk is ideally also substantially uniform and again is a central flow path or channel that allows oil to enter the impeller and the space between each disk. For example, the impeller can include two, three, four, or five annular disks mounted in a stacked array in combination with a solid disk. In the case of a combination of a plurality of annular disks and (at least) one solid disk, the head generated by the pump and the efficiency of the pump can be significantly increased compared to a single annular disk. However, once the number of disks exceeds five, the increase in head and efficiency tends to become smaller. It is desirable to set the number of disks in the impeller in the range of two to eight, preferably five. The radial width of each flat or planar annular disk is preferably in the range of about 20% to about 40% of the outer diameter of the disk. Accordingly, the diameter of the central hole in the annular disk is preferably in the range of about 20% to about 60% of the outer diameter of the disk. More preferably, the radial width of each annular disk is in the range of about 25% to about 30% of the outer diameter of the disk. Accordingly, the diameter of the central hole in the annular disk will be more preferably in the range of about 40% to about 50% of the outer diameter of the disk. The thickness of each disk is preferably in the range of about 0.5% to about 2% of the outer diameter of the disk.

[0017] In an embodiment of the present disclosure, the spacing between each disk of the impeller is preferably in the range of 0.2 mm to 5.0 mm, more preferably in the range of 0.2 mm to 2.0 mm, and even more preferably in the range of 0.2 mm to 1.5 mm; particularly preferably 0.5 mm. The thickness of each disk is preferably in the range of 0.5 mm to 2.0 mm, where the outer diameter of the disk is preferably in the range of about 100 mm to about 200 mm, more preferably in the range of about 100 mm to about 150 mm, for example, a diameter of about 120 mm. The distance between the uppermost disk of the impeller and the top housing plate of the housing is in the range of 0.05 mm to 0.2 mm. The pins or bolts interconnecting the impeller disks preferably have an elliptical cross-sectional profile (such as a 1:2 ratio), thus presenting a low-resistance profile in the direction of impeller rotation (i.e., having a shorter elliptical dimension parallel to the disk radius).

[0018] In one embodiment, the impeller of the rotary disk pump is directly coupled to the flywheel shaft to rotate therewith (i.e., without a gear arrangement). In this way, the impeller of the pump can rotate with the gyroscope flywheel shaft at a speed in the range of about 3,000 rpm to about 10,000 rpm. Due to the low hydrodynamic resistance of the impeller, the pump does not require a transmission, and the high rotational speed does not result in excessive wear in the lubricant or any significant cavitation effect.

[0019] In this way, the gyro stabilizer assembly of the present disclosure can utilize a simpler structural arrangement without the situation where a rotary shaft seal separates or isolates the rotary bearing from the working pressure of the flywheel cavity, as described in WO 2021 / 174315A1, and still achieve effective lubrication and cooling of the gyro stabilizer rotary bearing through the lubricant, which is evacuated and pumped under a rough vacuum working pressure in the range of less than 0.5 bar, preferably less than 0.2 bar, and more preferably in the range of about 1 mbar to 100 mbar (absolute pressure). The rotary disk pump can largely avoid the cavitation problem under the rough vacuum pressure present in the vacuum chamber and is also effective under the "splash" inlet conditions at the pump, which may occur in a heavily "precessing" vacuum chamber.

[0020] In one embodiment, either or both of the first rotary bearing and the second rotary bearing include a lubricant labyrinth seal, such as disposed therearound or thereabout. In this regard, the labyrinth seal of the first (upper) rotary bearing is desirably for preventing lubricant (oil) that has been applied to and has flowed through the first bearing from flowing towards the flywheel. (If the oil is dragged along the chamber wall by the rotating flywheel, power will be wasted). The labyrinth seal of the second (lower) rotary bearing is desirably for keeping lubricant (oil) that has been applied to and has flowed through the bearing away from the thrust bearing, which typically has its own supply of cooling oil. The lubricant labyrinth seal redirects the cooling lubricant to a reservoir or sump through a passage designed therefor. The reservoir or sump is configured and arranged in or on the housing such that the lubricant supplied, circulated, and / or delivered to the first rotary bearing and the second rotary bearing can be discharged from each respective bearing to return to the sump under gravity. In this regard, it should be understood that the liquid lubricant is typically an oil, such as a synthetic oil. In this regard, the lubricating oil preferably has a vapor pressure of less than 40 mbar at 80 °C.

[0021] It should be understood that the term "rotary bearing" as used throughout this document is understood to refer to a bearing designed to mount or support a flywheel shaft for rotation (preferably freely) about a rotational axis. Thus, the term "rotary bearing" will be understood to be a rotary bearing and will include a range of rotary bearing designs, including hydrodynamic bearings and rolling element bearings.

[0022] In one embodiment, the first rotary bearing and the second rotary bearing are configured as rolling element bearings; for example, the inner race of the rolling elements is rigidly attached to the flywheel shaft to rotate with the shaft, and the outer race is rigidly fixed relative to the housing. In an alternative embodiment, the first rotary bearing and the second rotary bearing can be configured as sliding bearings; for example, hydrodynamic sliding bearings.

[0023] In one embodiment, the operating pressure is at least partially a vacuum such that the chamber in which the flywheel is mounted forms a vacuum chamber. This reduces the aerodynamic drag on the flywheel, thereby reducing the power required to maintain the flywheel speed (rpm), while reducing the heat generated on the rotating flywheel by air resistance. In this way, the entire vacuum chamber in the gyro stabilizer assembly forms a single chamber operating at a vacuum pressure. As described above, the operating pressure is preferably less than or equal to about 0.2 bar, preferably in the range of 1 to 100 mbar.

[0024] In one embodiment, the lubricant circuit through which lubricant is circulated from a reservoir or sump to a bearing and then back to the reservoir or sump preferably includes an additional pump outside the housing and the vacuum chamber as a start-up, shut-down, and / or "boost" pump. This external pump may be referred to as a "supply pump" and is preferably a diffuser pump or a positive displacement pump and is preferably magnetically coupled to a brushless motor.

[0025] In one embodiment, the bearing lubrication system includes at least one lubricant delivery outlet, particularly a lubricant injection outlet, for directing or injecting oil lubricant to each of the first and second bearings. Thus, the bearing lubrication system may have an "oil injection" system. The flow rate of the oil is desirably selected to provide or allow an optimal exchange of heat generated at the bearing with the oil. Injecting the oil via the injection outlet ensures that the oil can be directed at the inner race of each bearing and / or the rolling or sliding elements therein to provide effective cooling to these components. Accordingly, the pump or "pump means" provided in the sump for delivering the lubricant (i.e., oil) from the sump to the first and second rotating bearings is preferably designed such that it can start up and deliver the necessary pressure to drive the oil at the required speed through the oil delivery outlet. In this regard, the pump or "pump means" may include a single pump stage or more than one pump stage. By carefully selecting or designing the pump means to deliver the required pressure and flow rate, the arrangement and sizing of the pump means can meet the requirements for circulating the oil through one or more filters and / or one or more heat exchangers in the oil circuit and then through the oil delivery outlet.

[0026] As described above, the lubrication system may also form a cooling system for the rotating bearings. Thus, the liquid lubricant (i.e., oil) typically acts as a coolant to carry heat away from the first and second rotating bearings. To this end, the lubricant circuit of the bearing lubrication system may include one or more heat exchangers for removing heat from the oil before it is delivered to the first and second rotating bearings. In this regard, the walls of the oil labyrinth seal may form a radiator or heat exchanger for the oil. Alternatively or additionally, when the oil returns to the sump under the action of gravity and / or is circulated from the sump to the rotating bearings, the walls of the flywheel housing and / or the walls of the reservoir or sump may form a radiator or heat exchanger for the oil, optionally via a cooling medium provided in those walls of the housing or sump (e.g., a water jacket), and / or optionally via fin elements formed in the walls. Then, this heat may be discharged as heated cooling water (e.g., discharged overboard). It should be noted that degassing of the oil is not required in the gyro stabilizer assembly of the present disclosure because the air concentration in the oil is particularly low at an absolute pressure of 1 - 30 mbar. This is beneficial as it simplifies the oil handling in the lubrication circuit and helps ensure that the delivery outlet provides a directed jet with sufficient speed to break through the boundary layer, thereby providing the necessary mixing and heat transfer. However, the oil is typically filtered before being re-injected.

[0027] In one embodiment, the lubricant circuit includes an accumulator for storing oil and maintaining oil pressure to buffer fluctuations in the oil pressure from the pump. Thus, the accumulator can support the injection pressure in the case of oil splashing at the pump and / or for a period of time when there may be no oil supply at the pump inlet of the sump pump, e.g., when the gyro stabilizer may be stuck for an extended period (e.g., 2 minutes) at a high precession angle (e.g., 70°) during a U-turn of a ship. The accumulator is preferably a bladder or piston accumulator. The oil pressure maintained by the accumulator in the lubricant circuit is preferably in the range of about 1.2 bar to about 3.2 bar. A check valve (non-return valve) is preferably located upstream of the accumulator to prevent backpressure from the accumulator from being applied to the sump or reservoir.

[0028] For the gyro assembly of the present disclosure, both the horizontal and vertical directions of the flywheel shaft are considered, and both directions pose challenges to lubrication in delivering a lubricant (e.g., oil) to the respective rotary bearings and then recovering the lubricant for reuse.

[0029] In a preferred embodiment, the flywheel shaft is mounted in the housing in a generally vertical orientation and rotates about a generally vertical axis of rotation. Thus, the first bearing and the second bearing respectively form an upper rotary bearing and a lower rotary bearing. In such a configuration, the gyro assembly of the present disclosure generally includes an additional lower rotary bearing (i.e., a third rotary bearing) as a thrust bearing to provide axial support for the flywheel and the flywheel shaft. The vertical flywheel shaft orientation is preferred because it allows the housing to be set as a pendulum with a natural stable point close to vertical. This means that no additional mechanism is required to ensure that the precession angle of the gyro assembly remains "centered" at mid-stroke. Thus, the oil returning from the upper and lower bearings is directed to a common reservoir or sump at the vacuum chamber and the lower region or base of the housing. Then, the oil in the reservoir / sump is recovered and (re)circulated by a rotary disk pump located in the reservoir / sump.

[0030] In an embodiment, the pump or "pump arrangement" in the sump or reservoir of the bearing lubrication system includes a two-stage pump arrangement to increase the pump outlet pressure. In such a pump arrangement, the rotary disk pump preferably constitutes the first stage, and the second stage preferably includes a centrifugal pump with guide vanes / vane.

[0031] In one embodiment, the gyro stabilizer assembly includes an electric motor for driving a flywheel to rotate about a rotational axis. In one embodiment, the rotating electric motor is mounted indoors. In an alternative embodiment, the rotating electric motor is mounted outdoors and is coupled to the flywheel shaft via an isolated magnetic coupling or a sealed shaft connection. The magnetic coupling is preferred to avoid the need for a rotating shaft seal. If a shaft connection to a rotating electric motor mounted outdoors is required, a rotating shaft seal will again be needed. However, the advantage here is that this arrangement is decoupled from large radial movement (runout) of the flywheel shaft, whereby the runout makes it difficult to seal effectively. In addition, the shaft connecting the rotating electric motor to the flywheel shaft only needs to transmit a relatively small rotational torque and can therefore have a relatively small diameter. This in turn limits the speed of the sealing contact surface (a reduced circumference at a given rpm results in a lower speed), which significantly extends the possible rpm before the sealing capacity becomes limited and reduces the rotational drag of the seal. In contrast, in the current arrangement, the rotating shaft seal is provided on the flywheel shaft, which must withstand the full gyroscopic torque that is completely reversed in each rpm cycle. As a result, the shaft diameter and circumference are much larger, resulting in a higher contact surface speed, higher wear, and the technical challenge of extending the seal life.

[0032] According to another aspect, the present disclosure provides a gyro stabilizer assembly for a marine vessel, comprising: a housing that defines a chamber for supporting at least a partial vacuum; a flywheel mounted within the chamber for rotating about a rotational axis under the partial vacuum; a flywheel shaft on which the flywheel is supported or mounted within the housing to rotate the flywheel about the rotational axis, the flywheel shaft being rotatably supported by a first rotary bearing located at one end region of the shaft and a second rotary bearing located at an opposite end region of the shaft; and a bearing lubrication system configured to supply lubricant from a lubricant reservoir to the rotary bearings via a lubricant circuit. The first rotary bearing and the second rotary bearing are arranged within the housing or operate under a partial vacuum (e.g., if a vacuum is only applied during use). The lubrication system includes a rotary disk pump in the reservoir for pumping or circulating the lubricant via the lubricant circuit.

[0033] In one embodiment of the gyro stabilizer assembly of the present disclosure, the rotary disk pump in the reservoir is coupled to and driven by the flywheel shaft. However, alternatively, the rotary disk pump can be separated from the flywheel shaft (i.e., not coupled to the flywheel shaft) and driven by a separate electric motor. As described above, the rotary disk pump is a centrifugal pump with an impeller that includes at least one substantially flat disk, and desirably two (or more) substantially flat disks that are mounted relative to each other in a spaced-apart, substantially parallel manner. The impeller typically has no guide vanes and can rotate at high speed with the lubricant being substantially laminar and without generating significant vibration or cavitation. The rotary disk pump is preferably an enclosed rotary disk pump. It preferably includes a first solid flat disk that is mounted to a second axially aligned annular flat disk in a uniformly spaced relationship, and the outer diameter of the annular flat disk is substantially the same as the outer diameter of the first disk.

[0034] As described above, since the structure and operation of a marine gyro stabilizer are generally well understood, this specification is not intended to provide a detailed description of all components of the gyro stabilizer assembly, such as the flywheel, flywheel shaft, gimbal bearings, etc. Instead, this specification directs the skilled reader to other publications for a description or explanation of those components.

[0035] According to another aspect, the present disclosure provides a marine vessel, such as a ship, that includes or incorporates the gyro stabilizer assembly of the present disclosure according to any of the above embodiments. The gyro stabilizer assembly is typically fixedly secured to the hull of the marine vessel, such as near the keel.

[0036] According to another aspect, the present disclosure provides a lifting system, such as for use with a crane, that includes the gyro stabilizer assembly of the present disclosure according to any of the above embodiments. In this case, the gyro stabilizer assembly is designed or adapted to be suspended on the lifting system together with a load to dampen or suppress undesired oscillatory rotation of the suspended load, such as oscillatory rotation caused by gusts of wind. Desirably, at least one gyro stabilizer assembly is provided for and / or along each axis that requires stabilization.

[0037] It should be understood that the term "gyro stabilizer assembly" as used throughout this document is understood to refer to a gyro stabilizer device or gyro stabilizer unit that can be incorporated or mounted in a vehicle such as a marine vessel, or incorporated or mounted in some other device that is subject to undesired rotational motion, such as roll motion caused by waves, in order to counteract and / or reduce such undesired motion. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] To more fully understand the present invention and its advantages, exemplary embodiments of the present invention are explained in more detail below with reference to the accompanying drawings, in which like reference numerals represent like parts, and in which:

[0039] Figure 1 is a schematic view of a gyro stabilizer assembly according to a preferred embodiment;

[0040] Figure 2 is a schematic perspective view of an impeller of a rotary disk pump of a reservoir or storage tank for the gyro stabilizer assembly in this embodiment;

[0041] Figure 3 is a schematic cross-sectional side view of an impeller of a rotary disk pump disposed in a reservoir or storage tank in the gyro stabilizer assembly;

[0042] Figure 4 is a graph showing the pump efficiency and outlet head or pressure of the rotary disk pump varying with the number of disks in the impeller;

[0043] Figure 5 is a schematic cross-sectional view of a hull of a ship including a gyro stabilizer assembly according to an embodiment of the present disclosure; and

[0044] Figure 6 is a schematic view of a lifting system including a gyro stabilizer assembly according to an embodiment of the present disclosure.

[0045] The accompanying drawings are included to provide a further understanding of the present invention, and are incorporated into and constitute a part of this specification. The accompanying drawings illustrate specific embodiments of the present invention and, together with the specification, are used to explain the principles of the present invention. Other embodiments of the present invention and many attendant advantages will be readily understood as they become better understood by reference to the following detailed description.

[0046] It should be understood that common and / or well-understood elements that may be useful or necessary in commercially viable embodiments need not be depicted in order to facilitate a more abstract view of the embodiments. Additionally, it will be noted that the elements of the accompanying drawings are not necessarily shown to scale relative to each other. It will also be understood that certain acts or steps in method embodiments may be described or depicted in a particular order of occurrence, and those skilled in the art will understand that such specificity of order is not actually required. Detailed Description

[0047] Referring to the accompanying drawings Figure 1, schematically shows a gyro stabilizer assembly 1 according to a preferred embodiment. The gyro stabilizer assembly 1 includes a housing 13 and a flywheel 33. The housing 13 encloses a chamber 12 for supporting a partial vacuum V (e.g., in the range of about 1 to 100 mbar) as the working pressure. The flywheel 33 is integral with or fixed to a substantially vertically oriented flywheel shaft 34 mounted within the vacuum chamber 12 for rotation about a substantially vertical spin axis or rotational axis Z under the working pressure. The flywheel shaft 34, on which the flywheel 33 is fixed and supported, is mounted in the housing 13 via an upper rotary bearing 21 and a lower rotary bearing 31 (also referred to as a "rotary bearing") and via a lower thrust bearing 32. The upper rotary bearing 21 and the lower rotary bearing 31 are located at opposite end regions of the shaft 34 for enabling the flywheel 33 to rotate about the rotational axis Z. The flywheel 33 may be integral with the shaft 34 or may be attached to the shaft 34. In this embodiment, the upper bearing 21 and the lower bearing 31 are in the form of rolling element bearings having rolling elements (e.g., steel balls or rollers) that are held between an inner race and an outer race and are movable between the inner race and the outer race. The inner race is firmly fixed to the shaft 34, and the outer race is firmly fixed to the housing 13. The substantially perpendicular orientation of the flywheel shaft 34 and the rotational axis Z allows the housing 13 to be set or mounted as a pendulum about a substantially horizontal axis, where the natural stable point is close to vertical. Thus, no mechanism is required to ensure that the precession angle of the gyroscope assembly 1 remains centered about the mid-stroke. The gyroscope assembly 1 includes an electric drive motor or spin motor 52 for driving the rotation of the flywheel 33 about the rotational axis Z, and the electric motor 52 is mounted on the housing 13 and operatively coupled to the flywheel shaft 34 via a magnetic coupling 53.

[0048] The gyro stabilizer assembly 1 further includes a lubrication system 8 (oil-based) for the upper rotary bearing 21 and the lower rotary bearing 31. The lubrication system 8 is configured to circulate oil O from a reservoir or sump 70 to each of the bearings 21, 31. The lubrication system 8 includes an oil circuit 9, which includes a series of interconnected pipelines or conduits 71, 79, 50, 51, 58, 59, 65 through which the oil O is circulated from the reservoir or sump 70 to the respective rotary / thrust bearings 21, 31, 32 and then back to the sump 70. To this end, the pipelines or conduits 71, 79, 50, 51, 65 of the oil circuit 9 can be (i.e., partially) outside the housing 13 and (partially) within the housing 13, through which the oil O is conveyed or supplied from the sump 70 to each rotary or thrust bearing 21, 31, 32. The upper rotary bearing 21 and the lower rotary bearing 31 are constructed and arranged within the housing 13 such that the oil O circulated or conveyed to the rotary bearings 21, 31 can be discharged from each respective bearing 21, 31 to return to the reservoir or sump 70 under the action of gravity. In this regard, the lubrication system 8 includes at least one pump 60 in the reservoir or sump or oil sump 70, which is coupled to and driven by the flywheel shaft 34 for circulating the lubricant O via the oil circuit 9 to the first rotary bearing 21 and the second rotary bearing 31. The pump 60 includes a rotary disk pump, which is a centrifugal pump having an impeller 6, as Figure 3 and Figure 4as shown. The impeller 6 includes two substantially flat disks 6a, 6b, one disk 6a having a generally solid circular shape and the other disk 6b having a generally circular or annular shape, coaxially mounted relative to each other in a spaced-apart, generally parallel arrangement by threaded rods, bolts or other fasteners 7, with a spacing between the disks of about 0.5 mm. These threaded rods or bolts 7 interconnecting the disks 6a, 6b of the impeller 6 have an elliptical cross-sectional profile (such as a ratio of 1:2), with a low resistance profile in the direction of rotation of the impeller 6 (i.e., having a shorter elliptical dimension parallel to the disk radius). The flat annular disk 6b has a central hole 5 for allowing oil to enter the space between the disks 6a, 6b and has an outer diameter substantially the same as that of the solid disk 6a. The radial width w of the annular disk 6b is about 25% of the outer diameter of the disk (120 mm). Thus, the diameter of the central hole 5 of the annular disk is about 50% of the outer diameter of the disk 6b. The thickness t of each disk 6a, 6b is preferably in the range of about 0.5 mm to 2.0 mm. The impeller 6 has no guide vanes and, when rotating, uses the principles of boundary layer and viscous drag to push the oil O from the reservoir or sump 70 along the lubricant circuit 9. Since the impeller 6 of the rotary disk pump 60 is designed without guide vanes, it can rotate at high speed in a substantially laminar flow of the lubricant and does not produce significant vibrations or cavitation. In this way, the impeller 6 of the rotary disk pump 60 can rotate with the gyroscope flywheel shaft 34 at a speed in the range of about 3,000 revolutions per minute to about 10,000 revolutions per minute. Due to the low hydrodynamic resistance of the impeller 6, the pump 60 does not require a transmission, and the high rotational speed does not produce any significant cavitation effect in the oil.

[0049] Referring to the accompanying drawings Figure 4 , it should be noted that the pump 60 can have an impeller 6 having a plurality of axially aligned annular disks 6b located above the solid disk 6a in a stacked array and evenly spaced from each other and from the solid disk 6a. The central openings 5 in each annular disk 6b are substantially uniform and again allow the oil O to enter the impeller 6 and into the central channel of the space between each disk 6a, 6b. For example, the impeller can include two, three, four or five annular disks 6b, which are mounted in a stacked array in combination with the solid disk 6a. As Figure 4 shown, by increasing the number of rotating disks 6a, 6b, the head generated by the pump 60 and its efficiency can be significantly increased, although this increase tends to become smaller once the number of disks exceeds five. Figure 4 shows the disk pump efficiency and head of synthetic (polyalphaolefin) oil O at a flow rate of 7 l / min at 80 °C, where the computational fluid dynamics (CFD) results are calculated for a pump inlet pressure of 30 mbar, a disk diameter of 120 mm and a shaft speed of 4800 rpm.

[0050] Therefore, the rotary disk pump 60 is operated to circulate or transport oil from the reservoir 70 to the upper bearing 21 and the lower bearing 31. The vertical orientation of the axis of rotation Z means that the oil O supplied to the upper bearing 21 and the lower bearing 31 is naturally guided to the sump or reservoir 70 by gravity. That is, the sump or reservoir 70 is located at the base of the housing 13 below the vacuum chamber 12 to collect oil from the upper rotary bearing 21, the lower rotary bearing 31, and the thrust bearing 32 via the return lines or passages 58, 59, 68 under the action of gravity, where the bearings 21, 31, 32 are disposed in the housing 13 at the operating pressure V. In this way, the vacuum chamber 12 is a single chamber operating at a pressure V. This not only reduces the aerodynamic drag on the flywheel 33, thereby reducing the power required to maintain the flywheel speed (rpm) and the heat generated by air resistance on the rotating flywheel 33, but also provides a simpler design of the gyro stabilizer assembly 1, where no rotary shaft seal is required to isolate the upper rotary bearing 21 and the lower rotary bearing 31 from the operating pressure V of the flywheel chamber 12. This simpler configuration of the gyro stabilizer assembly 1 in turn can facilitate the production of the gyro stabilizer assembly 1 on a smaller scale.

[0051] Reference Figure 1, the lubricant circuit 9 includes another pump 75 outside the housing 13 and the vacuum chamber 12, which is arranged to start, stop and boost the pump. In this way, before the flywheel 33 and the flywheel shaft 34 have started to operate (i.e., before the rotary disc pump 60 operates), this other pump 75 can be used to generate oil pressure in the lubricant circuit 9. This pump 75 can also be operated to increase the oil pressure in the pipelines or conduits 71, 79, 50, 51 to improve the oil delivery to the bearings 21, 31 when the rotary disc pump 60 is operating. This external pump 75 can be, for example, a vane centrifugal pump, and it can be magnetically coupled to a brushless motor. Oil flows from the pump 75 through the check valve 77 and through the filter 38 in the oil circuit 9, where the oil O flows to the oil cooler 39 via the pipeline 79. The oil cooler 39 is shown as two heat exchanger units 40, 41 in series, where the coolant is supplied or flows in through the pipeline or conduit 42 and flows out through the pipeline or conduit 44. The oil leaves the cooler 39 and flows to the oil accumulator 36, which stores the oil O and maintains the oil pressure to buffer the oil pressure fluctuations from the pumps 60, 75. The oil pressure maintained by the oil accumulator in the oil circuit 9 is preferably in the range of about 1.5 bar to about 3 bar (absolute pressure). The check valve (i.e., one-way valve) 77 located upstream of the oil accumulator 36 prevents the back pressure from the oil accumulator 36 from being applied to the reservoir or storage tank 70. Therefore, for the case of oil splashing at the pump 60 and / or when there may be no oil supply at the inlet of the reservoir pump 60 for a period of time, for example, when the gyro stabilizer 1 experiences an extended time at a high precession angle (e.g., about 70°) during a U-turn of the ship, the oil accumulator 36 can support the oil injection pressure at the bearings 21, 31, 32. The oil accumulator 36 is preferably a bladder type or piston type oil accumulator. Downstream of the oil accumulator 36, the oil flow splits between the pipeline 50 leading to the upper rotary bearing 21 and the pipeline 51 leading to the lower rotary bearing 31, and also splits to the thrust bearing 32. It will be noted that the oil accumulator 36 can be located anywhere along the oil circuit 9 between the pump 75 and the split in the pipelines to the two pipelines 50, 51.

[0052] The oil lubrication system 8 includes one or more oil injection outlets 54, 64, 67 at each of the upper rotary bearing 21, the lower rotary bearing 31, and the thrust bearing 32 for directing or injecting oil O via an oil passage 9. The flow rate of the oil is selected to provide the required exchange of heat generated at the bearings 21, 31, 32 into the oil. Thus, the oil lubrication system 8 also forms a cooling system for the bearings 21, 31, 32, where the oil serves as a coolant to carry heat away from the bearings. In particular, the oil injection via the oil injection outlets 54, 64 ensures that the oil O is directed at the rolling elements in the rotary bearings 21, 31 at a sufficient speed and pressure such that the oil O mixes with the boundary layer oil for effective lubrication and cooling effects. To this end, the oil passage 9 includes heat exchangers 40, 41 for removing heat from the oil O before it is delivered to the upper bearing 21 and the lower bearing 31. In this regard, when the oil returns to the reservoir 70 under the action of gravity, the wall 72 of the reservoir or the reservoir 70 can form or serve as a heat exchanger for the oil O, optionally via a cooling medium (e.g., in the form of a water jacket) provided in the wall 72 and / or via fin elements (not shown) formed in the wall. As noted above, the oil passage 9 includes at least one filter 38 for filtering the oil O before the oil O is injected again at the oil injection outlets 54, 64, 67.

[0053] Further referring to the Figure 1 drawings, it can be seen that oil labyrinth seals 55, 62 are provided around the upper bearing 21 and the lower bearing 31 to prevent the oil O applied to the bearings 21, 31 from flowing to where it should not flow, such as towards the flywheel 33 or the thrust bearing 32, and the oil O is cooled separately via a line 65 and a nozzle 67. These oil labyrinth seals 55, 62 direct the oil flow to the reservoir or the reservoir 70 via return lines or pipes 58, 59, 68. As described above, the reservoir or the reservoir 70 is arranged in or on the housing such that the oil supplied, circulated, or delivered to the first rotary bearing 21, the second rotary bearing 31, and the thrust bearing 32 is discharged from each respective bearing 21, 31 via the corresponding oil labyrinth seals 55, 62 to return to the reservoir 70 under the action of gravity. The ideal oil is a synthetic oil with a vapor pressure of less than 40 mbar at 80 °C.

[0054] The following tests were conducted using a rotary disk pump operating in a rough vacuum alone or in combination with a booster pump with guide vanes:

[0055] Test 1: The rotary disk pump 60 was operated at 4800 rpm in a rough vacuum. The rotary disk pump (without guide vanes / without blades) has been tested for pumping up to 6.7 l / min of synthetic polyalphaolefin oil, with an absolute inlet pressure of 32 mbar, an outlet pressure of 1.3 bar, and an oil temperature of 65 °C.

[0056] Test 2: The rotary disc pump 60 operates at 4800 rpm in rough vacuum, in combination with a diffuser booster pump or supply pump 75. The enclosed rotary disc pump is connected in series with the diffuser booster pump during the test and pumps up to 11.8 l / min of synthetic (polyalphaolefin) oil at an absolute inlet pressure of 37 mbar. For an oil temperature of 74 °C, an absolute pressure of 1.1 bar is delivered at the outlet of the rotary disc pump and an absolute pressure of 3.2 bar is delivered at the outlet of the diffuser pump.

[0057] Test 3: The rotary disc pump 60 operates at 3000 rpm in rough vacuum, in combination with a diffuser booster pump 75. The enclosed rotary disc pump is connected in series with the diffuser booster pump during the test and pumps up to 9.5 l / min of synthetic (polyalphaolefin) oil at an absolute inlet pressure of 14 mbar. For an oil temperature of 69 °C, an absolute pressure of 0.6 bar is delivered at the outlet of the rotary disc pump and an absolute pressure of 3.1 bar is delivered at the outlet of the diffuser pump.

[0058] Test 4: The rotary disc pump 60 operates at 4800 rpm at low pressure and in combination with a diffuser booster pump 75 (mixed flow air - oil). The enclosed rotary disc pump is connected in series with the diffuser booster pump during the test and pumps up to 11.7 l / min of synthetic (polyalphaolefin) oil at an absolute inlet pressure of 332 mbar and for an oil temperature of 70 °C, an absolute pressure of 1.0 bar is delivered at the outlet of the rotary disc pump and an absolute pressure of 3.1 bar is delivered at the outlet of the diffuser pump.

[0059] Advantages of the rotary disc pump include: it can run dry without damage, it can be operated at higher temperatures, it benefits from fluids of higher viscosities; it produces substantially laminar flow with little cavitation in a vacuum; it requires little maintenance; its production cost is low; it has a low height profile; it does not require a running - in period; it can pump gas - liquid mixtures; it is suitable for operation at high rotational speeds; and it does not interfere with the operation of starting the pump.

[0060] Referring to the attached drawings Figure 5 , there is shown a ship S, such as a steamer, a yacht or a boat, which includes a gyro stabilizer assembly 1 according to an embodiment of the present disclosure above. The gyro stabilizer assembly 1 is firmly fixed to the hull H of the ship S adjacent to the keel K.

[0061] Referring to the attached drawings Figure 6 , there is shown a lifting system, such as a crane C, which includes a gyro stabilizer assembly 1 according to an embodiment of the present disclosure as described above. In this case, the gyro stabilizer assembly 1 is designed to be suspended from the lifting system and is used to damp or suppress unwanted oscillatory rotations of a suspended load L, such as caused by gusts of wind, during a lifting operation. The gyro stabilizer assembly 1 is provided for and / or mounted along each axis that requires stabilization.

[0062] Although specific embodiments of the present invention have been shown and described herein, those of ordinary skill in the art will understand that there are various alternative and / or equivalent implementations. It should be understood that each exemplary embodiment is merely an example and is not intended to limit the scope, applicability, or configuration in any way. On the contrary, the foregoing summary and detailed description will provide those skilled in the art with a convenient roadmap for implementing at least one exemplary embodiment, and it should be understood that various changes can be made to the functions and arrangements of the elements described in the exemplary embodiments without departing from the scope set forth in the appended claims and their legal equivalents. Generally, this application is intended to cover any adaptation or variation of the specific embodiments discussed herein.

[0063] Generally, this disclosure is intended to cover any and all adaptations or variations of the specific embodiments discussed herein. For example, those skilled in the art will readily understand that the gyro stabilizer assembly 1 and system of this disclosure are not limited to being made of any specific materials described in the specific embodiments. On the contrary, those skilled in the art will understand that there is a range of suitable materials, and those skilled in the art can easily select a suitable material based on the known mechanical properties of the materials that make them suitable for this disclosure. Since this disclosure relates to engineering technologies from multiple disciplines, it can be expected that the conceptually "person skilled in the art" can include a group or team of multiple individuals with technical expertise and / or qualifications in one or more fields or disciplines including mechanical engineering, ocean engineering, and hydraulic engineering.

[0064] It should also be understood that, unless the context otherwise requires, the terms "comprising", "including", "containing", "having", "has" and their variants used in this document are intended to be understood in an inclusive (i.e., non-exclusive) sense, such that the processes, methods, apparatuses, devices or systems described herein are not limited to the features, integers, components, elements or steps recited, but may include other features, integers, components, elements or steps not expressly listed and / or inherent to such processes, methods, apparatuses, devices or systems. Further, unless expressly stated otherwise, the terms "a" and "an" used herein are intended to be understood to mean one or more. Additionally, the terms "first", "second", "third", etc. are used only as labels and are not intended to impose any numerical requirements on their objects or to establish any ranking of the importance of their objects. Further, references to positional terms (such as "below" and "above") used in the above description will be in the context of the embodiments depicted in the drawings and should not be construed as limiting the present invention to the literal interpretation of the term, but as understood by those skilled in the art in the appropriate context.

[0065] Reference numeral

[0066] 1 Gyro stabilizer assembly

[0067] 5 Central hole

[0068] 6 Impeller

[0069] 6a Solid flat disk

[0070] 6b Annular or ring-shaped disk

[0071] 7 Rod, bolt or fastener

[0072] 8 Lubrication system

[0073] 9 Oil passage

[0074] 12 Vacuum chamber

[0075] 13 Housing

[0076] 21 Upper bearing

[0077] 31 Lower bearing

[0078] 32 Thrust bearing

[0079] 33 Flywheel

[0080] 34 Flywheel shaft

[0081] 36 Oil accumulator

[0082] 38 Filter

[0083] 39 Oil cooler

[0084] 40 Heat exchanger

[0085] 41 Heat exchanger

[0086] 42 Coolant supply pipeline

[0087] 44 Coolant supply pipeline

[0088] 50 Oil supply pipeline

[0089] 51 Oil supply pipeline

[0090] 52 Motor

[0091] 53 Magnetic coupling

[0092] 54 Oil injection outlet

[0093] 55 Oil labyrinth seal

[0094] 58 Lubricant return channel

[0095] 59 Lubricant return channel

[0096] 60 Pump device

[0097] 62 Oil labyrinth seal

[0098] 64 Oil injection outlet

[0099] 65 Oil supply pipeline

[0100] 67 Oil injection outlet

[0101] 68 Lubricant return pipeline or channel

[0102] 70 Storage tank or reservoir

[0103] 71 Oil supply pipeline

[0104] 72 Wall of storage tank / reservoir

[0105] 75 Positive displacement pump

[0106] 77 Check valve

[0107] 79 Oil supply pipeline

[0108] Axis of rotation or spin axis of Z - axis

[0109] V Partial vacuum

[0110] O Lubricant / oil

[0111] w Radial width of annular disc

[0112] t Thickness of annular disc

[0113] S Sea - going ship or vessel

[0114] H Hull

[0115] K Keel

[0116] C Hoisting system or crane

[0117] L Load

Claims

1. A gyro stabilizer assembly, comprising: a housing that defines a chamber for supporting a working pressure; a flywheel mounted within the chamber for rotation about a rotational axis under the working pressure; a flywheel shaft on which the flywheel is mounted in the housing, the flywheel shaft being supported by a first rotary bearing and a second rotary bearing located at opposite end regions of the shaft to enable the flywheel to rotate about the rotational axis, wherein the first rotary bearing and the second rotary bearing are disposed in the housing under the working pressure or are used under the working pressure; and a bearing lubrication system including a lubricant circuit for circulating a liquid lubricant from a lubricant reservoir or sump to the first rotary bearing and the second rotary bearing, the lubricant reservoir or sump being positioned or arranged to collect the liquid lubricant from the first rotary bearing and the second rotary bearing under the action of gravity, wherein the bearing lubrication system includes a rotary disk pump in the reservoir or sump, the rotary disk pump being coupled to or driven by the flywheel shaft for circulating the lubricant via the lubricant circuit to the first bearing and the second bearing.

2. The gyro stabilizer assembly according to claim 1, wherein, The impeller of the rotary disk pump rotates via the flywheel shaft at a speed in the range of about 3,000 rpm to about 10,000 rpm, preferably 5,000 rpm to 10,000 rpm.

3. The gyro stabilizer assembly according to claim 1 or 2, wherein, The rotary disk pump is disposed within the reservoir or sump and is immersed in the lubricant.

4. The gyro stabilizer assembly according to any one of claims 1 to 3, wherein, The impeller of the rotary disk pump includes at least two substantially flat or planar disks mounted in an axially aligned and generally parallel arrangement relative to each other, wherein the at least two substantially flat or planar disks preferably include a first solid disk and a second annular disk, the second annular disk having an outer diameter substantially the same as that of the first disk.

5. The gyro stabilizer assembly according to any one of claims 1 to 4, wherein, The rotary disk pump coupled to or driven by the flywheel shaft constitutes a first stage of a two-stage pump arrangement provided in the reservoir or sump, and wherein a centrifugal pump having an impeller with guide vanes constitutes a second stage.

6. The gyro stabilizer assembly according to any one of claims 1 to 5, wherein, The liquid lubricant is an oil, such as a synthetic oil, and wherein the oil preferably has a vapor pressure of less than 40 mbar at 80 °C.

7. The gyro stabilizer assembly according to any one of claims 1 to 6, wherein, The lubricant circuit external to the housing includes an accumulator for storing the liquid lubricant and maintaining the pressure of the lubricant.

8. The gyro stabilizer assembly according to any one of claims 1 to 7, wherein, The lubricant circuit includes a positive displacement pump external to the housing chamber as a start-up, shut-down, and boost pump, the lubricant being circulated via the lubricant circuit from the reservoir or sump to the bearings and back, wherein the external pump is preferably a vane pump and is preferably magnetically coupled to a brushless motor.

9. The gyro stabilizer assembly according to any one of claims 1 to 8, wherein, The first rotary bearing and the second rotary bearing have a lubricant labyrinth seal around them to prevent the lubricant applied to the first rotary bearing and the second rotary bearing from flowing onto the flywheel; wherein the lubricant labyrinth seal is adapted to redirect the lubricant to the reservoir or sump via a passage.

10. The gyro stabilizer assembly according to any one of claims 1 to 9, wherein, The lubrication system includes a lubricant delivery outlet, in particular an injection outlet, for the targeted delivery or injection of lubricant at each of the first and second rotary bearings.

11. The gyro stabilizer assembly according to any one of claims 1 to 10, wherein, The first and second bearings are configured and arranged within the housing such that lubricant circulated to the first and second bearings is discharged from each respective bearing to return under gravity to the sump or reservoir.

12. The gyro stabilizer assembly according to any one of claims 1 to 11, wherein, The flywheel shaft is mounted within the housing in a substantially vertical orientation for rotation about a substantially vertical axis of rotation, wherein the first and second bearings respectively include an upper rotary bearing and a lower rotary bearing.

13. A gyro stabilizer assembly according to any one of claims 1 to 12, comprising an electric motor for driving the flywheel to rotate about the axis of rotation, wherein the electric motor is mounted external to the housing chamber and is coupled to the flywheel shaft via a magnetic coupling.

14. The gyro stabilizer assembly according to any one of claims 1 to 13, wherein, The operating pressure is a partial vacuum or a rough vacuum, preferably in the range of about 1 mbar to 100 mbar absolute pressure, such that the chamber in which the flywheel is mounted forms a vacuum chamber.

15. A gyro stabilizer assembly for a ship, comprising: a housing defining a chamber for supporting at least a partial vacuum; a flywheel mounted within the chamber for rotation about an axis of rotation under the partial vacuum; a flywheel shaft on which the flywheel is mounted in the housing for rotation of the flywheel about the axis of rotation, the flywheel shaft being rotatably supported by a first bearing located at one end region of the shaft and a second bearing located at the opposite end region of the shaft, wherein the first and second bearings are arranged in the housing for operation under the local vacuum; and a bearing lubrication system configured to supply oil from an oil reservoir to the first and second bearings via an oil line, the oil reservoir being arranged in or on the housing to collect oil from the first and second bearings under gravity, wherein the lubrication system includes a rotary disc pump for pumping or circulating oil via the oil line.

16. The gyro stabilizer assembly according to claim 15, wherein, The rotary disc pump in the oil reservoir is coupled to and driven by the flywheel shaft.

17. The gyro stabilizer assembly according to claim 15, wherein, The rotary disc pump is separate from the flywheel shaft and is driven by an electric motor.

18. The gyro stabilizer assembly according to any one of claims 15 to 17, wherein, The rotary disc pump includes two substantially flat discs mounted relative to each other in a spaced-apart, generally parallel arrangement, preferably including a first solid flat disc and a second axially aligned annular flat disc having the same outer diameter as the first disc.

19. A ship, in particular a boat or motor yacht, comprising a gyro stabilizer assembly according to any one of claims 1 to 18, wherein the gyro stabilizer assembly is fixed to the hull of the ship.

20. A lifting system, comprising a gyro stabilizer assembly according to any one of claims 1 to 18, wherein the gyro stabilizer assembly is designed to be suspended on the lifting system together with a load.

21. A gyro stabilizer assembly, comprising: a housing defining a chamber for supporting an operating pressure; A flywheel, the flywheel being installed indoors for rotating about a rotation axis under the working pressure; A flywheel shaft, the flywheel being mounted on the flywheel shaft in the housing, the flywheel shaft being supported by a first rotary bearing and a second rotary bearing located at opposite end regions of the shaft to enable the flywheel to rotate about the rotation axis, wherein the first rotary bearing and the second rotary bearing are arranged in the housing under the working pressure or are used under the working pressure; and A bearing lubrication system, the bearing lubrication system including a lubricant circuit for circulating a liquid lubricant from a lubricant reservoir or storage tank to the first rotary bearing and the second rotary bearing, the lubricant reservoir or storage tank being positioned or arranged to collect the liquid lubricant from the first rotary bearing and the second rotary bearing under the action of gravity, wherein the bearing lubrication system includes a pump device provided in the reservoir or storage tank, the pump device being coupled to the flywheel shaft and driven by the flywheel shaft for circulating the lubricant via the lubricant circuit to the first bearing and the second bearing.

22. The gyro stabilizer assembly according to claim 21, wherein, The pump device in the reservoir or storage tank includes a rotary disc pump, and wherein the impeller of the rotary disc pump is rotated by the flywheel shaft at a speed in the range of about 3,000 rpm to about 10,000 rpm, preferably 5,000 rpm to 10,000 rpm.

23. The gyro stabilizer assembly according to claim 22, wherein, The rotary disc pump is arranged in the reservoir or storage tank and is immersed in the lubricant.

24. The gyro stabilizer assembly according to any one of claims 21 to 23, wherein the pump device provided in the reservoir or storage tank includes a two-stage pump arrangement, wherein the rotary disc pump coupled to the flywheel shaft and driven by the flywheel shaft constitutes the first stage, and wherein a centrifugal pump having an impeller with guide vanes constitutes the second stage.

25. The gyro stabilizer assembly according to any one of claims 1 to 4, wherein the liquid lubricant is an oil, such as a synthetic oil, and wherein the oil preferably has a vapor pressure of less than 40 mbar at 80 °C.

26. The gyro stabilizer assembly according to any one of claims 22 to 25, wherein, The impeller includes a plurality of discs, the plurality of discs being mounted in an axially aligned and substantially parallel arrangement relative to each other.

27. The gyro stabilizer assembly according to any one of claims 22 to 26, wherein, The outer diameter of each disc of the impeller is in the range of about 100 mm to about 200 mm.

28. The gyro stabilizer assembly according to any one of claims 22 to 27, wherein, The radial width of each annular disc is in the range of about 20% to about 40% of the outer diameter of the annular disc.

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