Gyro Stabilizer Assembly

Abstract

The present disclosure relates to a gyro stabilizer assembly (1). The gyro stabilizer assembly (1) includes a housing (13) defining a chamber (12) for maintaining at least a partial vacuum, a flywheel (11) mounted within the chamber (12) to enable rotation about a spin axis (20) under the partial vacuum, a flywheel shaft (19) on which the flywheel (11) is mounted within the housing (13), and a bearing lubrication system (8). The flywheel shaft (19) is supported by a first spin bearing (21) and a second spin bearing (31) disposed at opposite end regions of the flywheel shaft (19) to rotate the flywheel (11) about the spin axis (20). The first spin bearing (21) and the second spin bearing (31) are disposed within the housing (12). The first spin bearing chamber (22) houses the first spin bearing (21) and is separated from the flywheel chamber (12) by a first shaft seal, and the second spin bearing chamber (24) houses the second spin bearing (31) and is separated from the flywheel chamber (12) by a second shaft seal. The bearing lubrication system (8) includes a lubricant circuit (9) for circulating lubricant to the first spin bearing (21) and the second spin bearing (31) from a reservoir or recovery chamber located at or adjacent to the second spin bearing (31). The lubricant circuit (9), located external to the housing (13), includes an oil accumulator for storing lubricant and maintaining the lubricant pressure, preferably between 1.7 bar and 3.7 bar.

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 gyrostabilizer assembly of the present disclosure is typically designed for use on marine vessels and will be conveniently described in this exemplary context. However, the gyrostabilizer assembly of the present disclosure is not limited to that particular application and may be designed for use in many other applications, such as other fixed and floating structures, other vehicles, hoisting systems, and / or camera mounts. [Background technology]

[0003] The discussion of background art in this specification, including reference to any document, should in no way be taken as an acknowledgement that such background art is well known art or forms part of the general knowledge in the field in Australia or anywhere else.

[0004] The structure and operation of marine gyrostabilizer assemblies are generally very well understood, and these devices are increasingly being adopted on commercial and recreational vessels. A gyrostabilizer assembly typically consists of a rotating flywheel mounted on a gimbal frame, which is rigidly mounted within the vessel. The specific manner in which the flywheel is constrained from rotational motion allows the angular momentum of the rotating flywheel to combine with the precession of the flywheel to generate a large, time-varying torque to directly counteract the vessel's dynamic rolling motion caused by wind and / or waves. Without any intervention, the vessel's rolling motion combines with the angular momentum of the flywheel to cause precession. This, in turn, combines with the angular momentum to produce a stabilizing torque that directly counteracts undesirable rotational motion of the vessel (e.g., wave-induced rolling). By positioning the gimbal in a specific manner, a roll stabilizing device is created that utilizes the naturally occurring physics of gyrodynamics and requires no further intervention to function. An example of a marine gyrostabiliser assembly is described in the applicant's Australian patent application no. AU2017-216483A1, the contents of which are incorporated herein in their entirety by direct reference.

[0005] Because the outer rim of a gyroscopic stabilizer flywheel rotates at high speeds, gimbal frames often consist of a chamber surrounding the flywheel that is evacuated to allow the flywheel to rotate in a vacuum. This reduces air resistance on the flywheel, reducing the power required to maintain the flywheel's rotational speed (rpm). It also reduces heat generated by air resistance on the rotating flywheel rim, improving efficiency. The spin bearings used to position and hold the flywheel around its spin axis are subjected to both high loads and high rotational speeds, which also generate heat and noise. Spin bearings and spin motors are typically placed in a vacuum chamber, avoiding the problems associated with sealing the vacuum chamber where the spin axis exits. However, having the spin bearing inside a vacuum chamber makes lubrication and cooling of the bearings difficult. In particular, the spin bearings and flywheel shaft are rotating, making it difficult to cool them by contacting a coolant jacket.

[0006] Pending Australian Patent Application AU2017-216483A1 describes an arrangement with an oil lubrication system for lubricating and cooling bearings, in which the oil flow rate to the bearings can be selected to provide both lubrication and heat exchange with the oil. Oil lubrication systems are desirable for noise reduction, longer bearing life, and heat removal within the bearings. In this system, oil is drawn from a reservoir or recovery chamber by one or more scavenge pumps. To operate the scavenge pumps, rotary shaft seals on the flywheel shaft separate the upper and lower bearing chambers from a vacuum chamber surrounding the flywheel. One seal is located below the upper bearing chamber and the other above the lower bearing chamber, and the upper and lower bearing chambers are connected by a drain line between them. This arrangement allows the flywheel to rotate in a partial or near-vacuum condition, at a pressure low enough that air resistance is substantially reduced or eliminated. Meanwhile, the bearing chambers (which are manifolded to operate at the same pressure) can operate at a pressure high enough for the scavenge pump to effectively pump oil to the spin bearings. Summary of the Invention [Problem to be solved by the invention]

[0007] It would be desirable to provide a new or improved gyrostabilizer arrangement utilizing a manifolded bearing housing isolated from the vacuum chamber and having a lubrication system that can reliably lubricate and cool the spin bearings within the manifold. [Means for solving the problem]

[0008] According to one broad aspect, the present disclosure provides a gyroscopic stabilizer assembly. The gyroscopic stabilizer assembly includes a housing defining a flywheel chamber for holding an operating pressure, a flywheel mounted in the flywheel chamber to enable rotation about a spin axis under the operating pressure, a flywheel shaft on which the flywheel is mounted within the flywheel chamber, a first spin bearing chamber containing a first spin bearing and separated from the flywheel chamber by a first shaft seal, a second spin bearing chamber containing a second spin bearing and separated from the flywheel chamber by a second shaft seal, and a bearing lubrication system. The flywheel shaft is supported by first and second spin bearings disposed at opposing end regions of the flywheel shaft. The bearing lubrication system includes a lubricant circuit for circulating lubricant from a reservoir or recovery chamber disposed in or adjacent to the second spin bearing chamber to the first and second spin bearings to collect lubricant under gravity from the first and second spin bearings. A pump is provided within the reservoir or recovery chamber. The pump is coupled to and driven by the flywheel shaft to circulate the lubricant in the lubricant circuit to the first spin bearing and the second spin bearing.

[0009] In one embodiment of the present disclosure, the pressure in each of the first and second spin bearing chambers is equal to or greater than the operating pressure in the flywheel chamber. In this regard, the pressure in each of the first and second spin bearing chambers is preferably between atmospheric pressure and the operating pressure, but is preferably equal to or greater than about 0.2 bar, more preferably equal to or greater than about 0.4 bar. Thus, the first and second shaft seals serve to isolate the first and second spin bearing chambers from the operating pressure in the flywheel chamber.

[0010] This is a type of centrifugal pump having an impeller consisting of at least one substantially flat or plain disk, preferably two (or more) substantially flat disks mounted generally parallel and spaced apart from one another. The impeller is typically vaneless and, as it rotates, uses the principles of boundary layer and viscous drag to force a liquid lubricant (e.g., oil) along a lubricant circuit from a reservoir or collection chamber. The vaneless design of the impeller of a rotary disc pump allows for the pump to rotate at high speeds with substantially laminar flow of the lubricant without generating significant vibration or cavitation. The rotary disc pump is preferably a hermetic rotary disc pump. It preferably includes a first solid flat disk mounted in a uniformly spaced relationship to at least one second, axially aligned, annular flat disk, preferably of substantially the same outer diameter as the first disk. A central opening in the annular disk allows for central flow or passage of oil through the impeller and into the space between the disks. This "pump means" in the reservoir or recovery chamber may be referred to as a "return pump" for returning lubricating oil from the reservoir to the lubricating oil circuit.

[0011] In one embodiment of the present disclosure, a rotary disc pump includes a plurality of axially aligned annular discs, preferably having substantially the same outer diameter as the first disc. The plurality of annular discs may be mounted in a stacked array above the first disc, preferably spaced substantially uniformly from one another and / or from the first disc. The central opening of each annular disc is preferably substantially uniform, again allowing for central flow or passage of oil into the impeller and into the spaces between each disc. For example, the impeller may include two, three, four, or five annular discs mounted in a stacked array in combination with (at least) one solid disc. By combining multiple annular discs with a solid disc, the pressure head generated by the pump and the efficiency of the pump can be substantially improved compared to a single annular disc. However, the improvement in pressure head and efficiency tends to decrease when the number of discs exceeds five. Desirably, the number of discs provided in the impeller ranges from two to eight, and preferably five. Each flat or planar annular disc preferably has a radial width ranging from about 20% to about 40% of the outer diameter of the disc. Thus, the central opening of the annular disc preferably has a diameter in the range of about 20% to about 60% of the outer diameter of the disc. More preferably, the radial width of each annular disc is in the range of about 25% to about 30% of the outer diameter of the disc. Thus, the central opening of the annular disc more preferably has a diameter in the range of about 40% to about 50% of the outer diameter of the disc. Each disc preferably has a thickness in the range of about 0.5% to about 2% of the outer diameter of the disc.

[0012] 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, even more preferably in the range of 0.2 mm to 1.5 mm, and particularly preferably 0.5 mm. The thickness of each disk is preferably in the range of 0.5 mm to 3 mm, and the outer diameter of the disk is preferably in the range of about 100 mm to about 300 mm, more preferably in the range of about 100 mm to about 200 mm, for example, a diameter of about 120 mm. The distance between the top (annular) disk of the impeller and the upper casing plate of the housing is in the range of 0.05 mm to 0.2 mm. The pins or bolts interconnecting the disks of the impeller preferably have an elliptical cross-sectional shape (e.g., a 1:2 ratio) so as to present a low profile in the direction of rotation of the impeller (i.e., with the short elliptical dimension parallel to the radius of the disk).

[0013] In one embodiment, the rotary disk pump's impeller is directly coupled to the flywheel shaft for rotation (i.e., there are no gears). In this manner, the pump's impeller can rotate with the gyroscopic flywheel shaft at speeds ranging from about 3,000 rpm to about 10,000 rpm. Because the impeller's hydrodynamic resistance is low, the pump does not require gears, and high rotational speeds do not lead to excessive wear or significant cavitation effects in the lubricating oil.

[0014] In one embodiment, the first and second spin bearings have lubricant labyrinths around them. The labyrinth of the (upper) first spin bearing is applied to that bearing and acts to prevent lubricant (oil) flowing through that bearing from flowing onto the flywheel. If the oil were dragged along the chamber wall by the rotating flywheel, this would waste power. The labyrinth of the (lower) second spin bearing is applied to that bearing and acts to prevent lubricant (oil) flowing through that bearing from reaching the thrust bearing, which requires a cooling oil supply. The lubricant labyrinth directs the cooling lubricant to a reservoir or recovery chamber through a passage designed for this purpose. The reservoir or recovery chamber is configured and arranged within or on the housing so that the lubricant supplied, circulated, or provided to the first and second spin bearings is drained from the respective bearings to return to the reservoir or recovery chamber under gravity. In this regard, it is 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 at 80°C of less than 40 mbar.

[0015] The term "spin bearing" as used throughout this document means a bearing designed to mount or support a flywheel shaft for rotation, preferably free rotation, about a spin axis. As such, the term "spin bearing" is understood to refer to a rotational bearing and includes a range of rotational bearing designs such as hydrodynamic bearings and rolling bearings.

[0016] For example, the inner race for the rolling elements may be rigidly attached to the flywheel shaft for rotation therewith, while the outer race may be rigidly fixed relative to the housing. In an alternative embodiment, the first and second spin bearings may be configured as plain bearings, e.g., plain hydrodynamic bearings.

[0017] In one embodiment, the operating pressure is at least a partial vacuum, such that the chamber in which the flywheel is mounted forms a vacuum chamber. This reduces air resistance against the flywheel, reducing the power required to maintain the flywheel's rotational speed (rpm) and reducing the heat generated by air resistance against the rotating flywheel. The operating pressure is preferably about 0.5 bar or less, more preferably 0.2 bar or less, and even more preferably in the range of about 1 to 100 mbar (absolute). Pressure values ​​given herein are absolute pressure values ​​unless otherwise specified.

[0018] In an embodiment, the lubrication oil circuit, in which lubrication oil is circulated from a reservoir or collection chamber to the bearings and then back to the reservoir or collection chamber, preferably includes an additional pump external to the housing and flywheel chamber as a start, stop, and "pressure boost" pump. This external pump may be called a "feed pump" or "boost pump" and is preferably a vane or positive displacement pump, preferably magnetically coupled to a brushless electric motor.

[0019] In one embodiment, the bearing lubrication system includes at least one lubricant outlet, particularly a lubricant injection port, for targeted delivery or injection of oil lubricant in each of the first and second spin bearings. Thus, the bearing lubrication system can have an "oil jet" system. The oil flow rate is preferably selected to exchange heat generated in the bearings with the oil. Injection of oil through the injection port ensures that the oil is directed toward the inner race of each bearing and / or the rolling or sliding elements therein, providing effective cooling for these components. Therefore, pump means provided in the reservoir for delivering lubricant (i.e., oil) from the reservoir to the first and second spin bearings are designed to prime and deliver the pressure required to drive the oil through the oil outlet port at the required speed. In this regard, the "pump means" may consist of a single pump stage or multiple pump stages. By carefully selecting the pumping means to provide the required pressure and flow rate, the pumping means can be arranged and sized to meet the requirements for circulating oil through one or more filters and / or one or more heat exchangers in the oil circuit and then through the oil delivery outlet.

[0020] As mentioned above, the lubrication system can also form a cooling system for the spin bearings. In this way, the liquid lubricant (i.e., oil) typically acts as a coolant, carrying heat away from the first and second spin bearings. To this end, the lubrication oil circuit of the bearing lubrication system can include one or more heat exchangers for removing heat from the oil before it is supplied to the first and second spin bearings. A flow path or conduit for transporting the lubricating oil along the lubrication circuit is preferably at least partially, and optionally completely, integrated into or contained within the flywheel casing or housing. Furthermore, a channel or conduit for transporting a coolant for cooling the lubricating oil is also preferably integrated into or contained within the flywheel casing or housing to form a cooling jacket. From this perspective, the walls of the oil labyrinth can form a heat sink or heat exchanger for the oil. Alternatively or additionally, the walls of the flywheel housing and / or the walls of the reservoir or recovery chamber can form a heat sink or heat exchanger for the oil as it returns under gravity to the reservoir and / or is circulated from the reservoir to the spin bearings, optionally via a cooling medium provided in those walls of the housing or reservoir (e.g., a water jacket) and / or optionally via fin elements formed in the walls. This heat can then be rejected (e.g., overboard) as heated cooling water.

[0021] In one embodiment, the lubrication oil circuit includes an oil accumulator for storing oil and maintaining oil pressure to mitigate fluctuations in oil pressure from the pump. The oil accumulator can therefore support injection pressure during periods of oil splashing at the pump and / or periods when there may be no oil supply from the pump inlet to the pump, such as when the gyrostabilizer is stuck at a high precession angle (e.g., 70°) for a long period (e.g., 2 minutes) during a vessel U-turn. The oil accumulator is preferably a bladder-type or piston-type oil accumulator. The oil pressure maintained by the oil accumulator in the lubrication oil circuit is preferably in the range of approximately 1.7 bar to approximately 3.7 bar (absolute pressure). A non-return valve (check valve) is preferably located upstream of the oil accumulator to prevent back pressure from the accumulator from being applied to the reservoir.

[0022] The gyroscope assembly of the present disclosure contemplates both horizontal and vertical orientations of the flywheel shaft, each of which presents challenges for lubrication in terms of getting lubricant (e.g., oil) to the respective spin bearings and then recovering the lubricant for reapplication.

[0023] In a preferred embodiment, the flywheel shaft is mounted in a generally vertical orientation within the housing so as to rotate about a generally vertical spin axis. Thus, the first and second spin bearings form the upper and lower spin bearings, respectively. In such a configuration, the gyroscope assembly of the present disclosure typically includes an additional lower spin bearing (i.e., a third spin bearing) as a thrust bearing to axially support the flywheel and flywheel shaft. A vertical flywheel shaft orientation is preferred because it allows the housing to be configured as a pendulum with a natural stable point near the vertical. This means that no extra mechanism is required to ensure that the precession angle of the gyroscope assembly remains "centered" around the mid-stroke. Oil returning from the upper and lower bearings is directed to a common reservoir located below the second spin bearing chamber, in the lower region or bottom of the housing. The oil in the reservoir is scavenged and (re)circulated by a rotary disc pump located within the reservoir.

[0024] In one embodiment, the pump or "pump means" in the reservoir or recovery chamber of the bearing lubrication system includes a two-stage pump arrangement for increasing the pump outlet pressure, where a rotary disc pump forms the first stage and the second stage is preferably formed by a vane pump or vaned centrifugal pump.

[0025] In one embodiment, the gyrostabilizer assembly includes an electric motor for driving rotation of the flywheel about the spin axis. In one embodiment, the spin motor is mounted within the chamber. In an alternative embodiment, the spin motor is mounted outside the chamber and coupled to the flywheel shaft via either an insulated magnetic coupling or a sealed shaft connection. A magnetic coupling is preferred to avoid the need for a rotary shaft seal. If a shaft connection to the spin motor mounted outside the chamber is required, a rotary shaft seal would still be required. However, the advantage here is that this arrangement isolates the flywheel shaft from the large radial motion (runout) that would make effective sealing difficult. Furthermore, the shaft connecting the spin motor to the flywheel shaft can be relatively small in diameter because it only needs to transmit a relatively small spin torque. This limits the speed of the seal interface (smaller circumferences at a given RPM reduce speed), significantly extending the possible RPMs before seal capacity is reached and reducing the rotational resistance of the seal. In contrast, in current arrangements, the rotary shaft seal is located on the flywheel shaft, which must withstand the full gyroscopic torque, which fully reverses with each rotational speed cycle. The shaft diameter and circumference are therefore much larger, leading to higher contact surface speeds, higher wear, and technical challenges related to extending seal life.

[0026] According to another aspect, the present disclosure provides a gyroscopic stabilizer assembly comprising: a housing defining a flywheel chamber for holding an operating pressure; a flywheel mounted in the flywheel chamber to enable rotation about a spin axis under the operating pressure; a flywheel shaft on which the flywheel is mounted within the flywheel chamber; a first spin bearing chamber containing a first spin bearing and separated from the flywheel chamber by a first shaft seal; a second spin bearing chamber containing a second spin bearing and separated from the flywheel chamber by a second shaft seal; and a bearing lubrication system. The flywheel shaft is supported by first and second spin bearings disposed at opposing end regions of the flywheel shaft. The bearing lubrication system includes a lubricant circuit for circulating lubricant from a reservoir or recovery chamber disposed at or adjacent to the second spin bearing to the first and second spin bearings. A lubricant circuit provided outside the housing includes an oil accumulator for storing lubricant and maintaining the pressure of the lubricant. The pressure is preferably between 1.7 bar and 3.7 bar.

[0027] In an embodiment of the gyrostabilizer assembly of the present disclosure, the rotary disc pump in the reservoir is coupled to and driven by the flywheel shaft. However, alternatively, the rotary disc pump may be separate from (i.e., not coupled to) the flywheel shaft and driven by a separate electric motor. As explained above, a rotary disc pump is a type of centrifugal pump having an impeller with at least one substantially flat disc, preferably two (or more) substantially flat discs mounted generally parallel and spaced apart from each other. The impeller is typically vaneless and can rotate at high speeds with substantially laminar flow of lubricating oil without generating significant vibration or cavitation. The rotary disc pump is preferably a sealed rotary disc pump and preferably includes a solid, flat first disc and an axially aligned, annular, flat second disc having the same outer diameter as the first disc.

[0028] As noted above, the structure and operation of gyrostabilizers is generally very well understood, and therefore this specification does not aim to provide a detailed description of all of the components of a gyrostabilizer assembly, such as the flywheel, flywheel shaft, gimbal bearing, etc. Rather, this specification directs those skilled in the art to other publications for descriptions or explanations of those components.

[0029] According to another aspect, the present disclosure provides a marine vessel, such as a boat, including or incorporating a gyrostabilizer assembly of the present disclosure according to any one of the above-described embodiments. The gyrostabilizer assembly is typically fixedly secured to the hull of the vessel, for example adjacent the keel.

[0030] According to a further aspect, the present disclosure provides a hoisting system, e.g., for use with a crane, including a gyroscopic stabilizer assembly of the present disclosure according to any of the above-described embodiments. In this context, the gyroscopic stabilizer assembly is designed or adapted to be suspended from the hoisting system together with a load and operates to damp or suppress undesirable oscillatory rotation of the load when suspended during a hoisting operation, e.g., caused by wind gusts. Preferably, at least one gyroscopic stabilizer assembly is provided for and / or mounted along each axis of stabilization required.

[0031] The term "gyrostabilizer assembly" as used throughout this document refers to a gyrostabilizer device or gyrostabilizer unit that may be incorporated into or installed on a vehicle, such as a watercraft, or other device that is subject to undesirable rotational motion (such as rolling motion due to waves) to counteract and / or reduce such undesirable motion. [Brief explanation of the drawings]

[0032] For a more complete understanding of the present invention and its advantages, exemplary embodiments thereof will be described in more detail in the following description taken in conjunction with the accompanying drawings, in which: [Figure 1] FIG. 2 is a schematic partial cross-sectional view of a vacuum chamber assembly in a gyrostabilizer assembly according to a preferred embodiment. [Figure 2] FIG. 1 is a schematic perspective view of a gyrostabilizer assembly according to a preferred embodiment. [Figure 3] FIG. 1 is a schematic perspective view of an impeller of a rotary disc pump for a reservoir or recovery chamber of a gyrostabilizer assembly according to an embodiment. [Figure 4] FIG. 1 is a schematic cross-sectional side view of an impeller of a rotary disc pump provided in a reservoir or recovery chamber of a gyrostabilizer assembly. [Figure 5]1 is a chart showing the change in pump efficiency and outlet head or pressure of a rotary disc pump with the change in the number of discs in the impeller. [Figure 6] FIG. 1 is a schematic cross-sectional view of a hull of a vessel including a gyro stabilizer assembly according to an embodiment of the present disclosure. [Figure 7] FIG. 1 is a schematic perspective view of a hoisting system including a gyrostabilizer assembly according to an embodiment of the present disclosure.

[0033] The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate certain embodiments of the invention and, together with the description, serve to explain the principles of the invention. Other embodiments of the invention and many of the attendant advantages will be readily appreciated by reference to the following detailed description.

[0034] It will be understood that common and / or well-understood elements that may be useful or necessary in commercially feasible embodiments have not necessarily been depicted in order to facilitate a more abstract view of the embodiments. Additionally, it should be noted that elements in the figures are not necessarily drawn to scale relative to each other. Also, while certain acts or steps in method embodiments may be described or depicted in a particular order of occurrence, those skilled in the art will understand that such specificity with respect to order is not actually required. DETAILED DESCRIPTION OF THE INVENTION

[0035] Referring to FIG. 1, a gyrostabilizer assembly 1 with a vacuum chamber assembly 10 according to a preferred embodiment of the present disclosure is schematically illustrated. The gyrostabilizer assembly 1 includes a housing 13 enclosing a flywheel chamber 12 for supporting a partial vacuum V (e.g., in the range of approximately 1 to 100 mbar) as an operating pressure. A flywheel 11 is housed within the flywheel chamber or vacuum chamber 12 formed within the housing 13. The housing is rotatably mounted on a precession bearing stub 14 fixed to the housing 13. A precession bearing 15 is mounted on the stub shaft 14, which defines a precession axis. Rotation of the vacuum chamber assembly 10 about the precession axis is controlled by a precession control device, such as a damper or actuator, as known in the art. The precession bearing stub 14 also includes a precession damper or actuator mount 16. The flywheel 11 is mounted on a flywheel shaft 19, which may be fixed to the flywheel shaft 19 or, as shown, may be integrally formed with the flywheel shaft 19. The flywheel shaft 19 is positioned relative to the housing 13 by an upper spin bearing 21 and a lower spin bearing 31 so that the flywheel 11 can rotate relative to the housing 13 about a spin axis 20 driven by a spin motor.

[0036] In this embodiment, the upper and lower bearings 21, 31 are in the form of rolling element bearings having movable rolling elements (e.g., steel balls or rollers) held between an inner race rigidly fixed to the shaft 11 and an outer race rigidly fixed to the housing 13. The generally vertical orientation of the flywheel shaft 11 and spin axis 20 allows the housing 13 to be installed or mounted as a pendulum about a generally horizontal axis with a natural stability point near vertical. As a result, no mechanism is required to ensure that the precession angle of the gyroscope assembly 1 remains centered around the mid-stroke. The upper spin bearing 21 is located within the upper spin bearing chamber 22. Similarly, the lower spin bearing 31 is located within the lower spin bearing chamber 24. Gyrostabilizers in which the flywheel shaft 34 is nominally vertical (i.e., oscillates, for example, up to ±70 degrees on either side of vertical during use) typically have not been provided with a circulating oil lubrication system because, as mentioned above, the shaft seals provided between the vacuum chamber 12 and the spin bearing chambers 22, 24 have had leakage problems due to the high surface speeds and large runout. The current arrangement of the oil circuit within the gyrostabilizer assembly 1, described in detail below, is leak-tight. However, oil that may leak from the bearing chambers 22, 24 into the flywheel chamber 12 can be purged by returning it to the oil circuit.

[0037] Referring to FIG. 2, the gyrostabilizer assembly 1 includes an oil-based lubrication system for the upper and lower spin bearings 21, 31, configured to circulate oil O from an oil reservoir or recovery chamber 70 to each of the spin bearings 21, 31. FIG. 2 also shows a lubrication system 8 or oil circuit 9 that provides lubrication and cooling to the upper spin bearing 21, the first lower spin bearing 31, and the second lower spin bearing 32. The second lower spin bearing 32 may be a bearing type suitable for large thrust loads to support a flywheel (omitted from FIG. 1 for clarity). Also shown in FIG. 2 are seals 33, 34 between the bearing chambers 22, 24 and the flywheel chamber 12. These seals ensure that the bearing chambers are at a different pressure than the vacuum chamber, preventing the free inflow of lubricant into the vacuum chamber 12. In this regard, the first and second bearing chambers 22, 24 are preferably at a pressure ranging from approximately 0.3 bar to 1 bar, more preferably 0.4 bar to 0.6 bar (absolute). There are two primary advantages to having the bearing chambers 22, 24 at a different pressure than the vacuum chamber. First, pumping oil out of the vacuum chamber is less likely due to, for example, cavitation. Second, the pressure differential between the vacuum chamber 12 and each spin bearing chamber 22, 24 can aid in energizing the seals 33, 34. The seals 33, 34 are disposed around the flywheel shaft 19 and may be any suitable rotary shaft seals. An electric drive motor, or spin motor 52, for driving rotation of the flywheel 11 and shaft 19 about the spin axis 20 is mounted in the housing 13 and operatively coupled to the flywheel shaft 19 via a magnetic coupling 53.

[0038] Thus, the lubrication system 8 includes an oil circuit 9 consisting of a series of interconnected lines or conduits 71, 79, 50, 51, 58, 59, 65. Through this circuit, oil O is pumped or circulated from a reservoir or recovery chamber 70 to each of the spin bearings 21, 31, 32 and then returned to the reservoir 70. Thus, the lines or conduits 71, 79, 50, 51, 65 of the oil circuit 9 may be both (partially) external and (partially) internal to the housing 13, through which the oil O is pumped or supplied from the oil reservoir 70 to each of the spin bearings 21, 31, 32. The upper and lower spin bearings 21, 31 are constructed and arranged within the housing 13 such that the oil O circulated or supplied to the spin bearings 21, 31 flows out of the respective bearings 21, 31 to return to the reservoir 70 under gravity. In this regard, the lubrication system 8 includes at least one pump 60 coupled to and driven by the flywheel shaft 34 within a reservoir or recovery chamber 70. The pump 60 is coupled to and driven by the flywheel shaft 34 to circulate the lubricating oil O through the oil circuit 9 to the first and second spin bearings 21, 31. As shown in FIGS. 3 and 4, the pump 60 is a rotary disc pump, a type of centrifugal pump, equipped with an impeller 6. The impeller 6 includes two substantially flat discs 6a, 6b. One disc 6a is generally solid and circular, while the other disc 6b is generally annular or ring-shaped. The discs 6a, 6b are mounted coaxially and generally parallel to each other at a distance from each other by threaded stems, bolts, or other fasteners 7, with the discs spaced apart by approximately 0.5 mm. These stems or bolts 7 interconnecting the discs 6a, 6b of the impeller 6 have an elliptical cross-sectional shape (e.g., a 1:2 ratio) for a low profile in the direction of rotation of the impeller 6 (i.e., for having a short elliptical dimension parallel to the disc radius).

[0039] The annular disc 6b has a central opening 5 for oil passage into the space between the discs 6a and 6b and has substantially the same outer diameter as the solid circular disc 6a. The radial width w of the annular disc 6b is approximately 25% of the disc's outer diameter (120 mm). Therefore, the central opening 5 of the annular disc has a diameter approximately 50% of the outer diameter of the disc 6b. The thickness t of each disc 6a and 6b is preferably in the range of approximately 0.5 mm to 2.0 mm. The impeller 6 is vaneless and, as it rotates, uses the principles of boundary layer and viscous drag to push oil O from the reservoir or recovery chamber 70 along the lubricating oil circuit 9. Because the impeller 6 of the rotary disc pump 60 is vaneless, it can rotate at high speeds while maintaining a substantially laminar flow of the lubricating oil, without generating significant vibration or cavitation. In this way, the impeller 6 of the rotary disc pump 60 can rotate at speeds ranging from approximately 3,000 rpm to approximately 10,000 rpm together with the gyroscopic flywheel shaft 34. Because the impeller 6 has low hydrodynamic resistance, the pump 60 does not require gears, and its high rotational speed does not cause significant cavitation effects in the oil. The rotary disc pump 60 operates to circulate or supply oil from a reservoir 70 to the upper and lower bearings 21, 31. Because the spin axis 20 is vertically oriented, the oil O supplied to the upper and lower bearings 21, 31 is guided by gravity to the reservoir or recovery chamber 70. That is, the reservoir or recovery chamber 70 is located at the bottom of the housing 13 below the lower bearing chamber 24 to recover oil through return lines or channels 58, 59, 68 from the upper and lower spin bearings 21, 31 and thrust bearing 32 under gravity.

[0040] Referring to FIG. 5, a pump 60 can have an impeller 6 having multiple axially aligned annular discs 6b stacked above a solid disc 6a. The impeller 6 can include multiple axially aligned annular discs 6b spaced uniformly above the solid disc 6a, both from each other and from the solid disc 6a. The central opening 5 of each annular disc 6b is substantially uniform, again allowing for central passage of oil O into the impeller 6 and into the spaces between each disc 6a, 6b. For example, the impeller can include two, three, four, or five annular discs 6b mounted in a stacked arrangement in combination with a solid disc 6a. As can be seen in FIG. 4, increasing the number of rotating discs 6a, 6b can significantly improve the pressure head generated by the pump 60 as well as its efficiency, although improvements tend to diminish when the number of discs exceeds five. Figure 4 shows the disc pump efficiency and pressure head when synthetic (polyalphaolefin) oil O is used at 80°C, with a flow rate of 7 liters / min, a disc diameter of 120 mm, and a shaft speed of 4800 rpm.

[0041] Returning to FIG. 2 , the lubricating oil circuit 9 includes an additional pump 75 external to the housing 13 and vacuum chamber 12, which serves as a start-up, stop-down, and boost pump. This additional pump 75 can thus be employed to generate oil pressure in the lubricating oil circuit 9 before the flywheel 33 and flywheel shaft 34 begin operating (i.e., before the rotary disc pump 60 is activated). This pump 75 can also be operated to boost oil pressure in the lines or conduits 71, 79, 50, and 51 when the rotary disc pump 60 is operating, to improve oil supply to the bearings 21 and 31. This external pump 75 may be, for example, a vaned centrifugal pump magnetically coupled to a brushless electric motor. From the pump 75, oil flows through a check valve 77 and a filter 38 through the oil circuit 9, and oil O flows through a conduit 79 to the oil cooler 39. The oil cooler 39 is shown as two heat exchangers 40, 41 connected in series, with cooling water supplied or flowing in through line or conduit 42 and flowing out through line or conduit 44. Oil exits the cooler 39 and flows to the oil accumulator 36, which stores the oil and maintains oil pressure to buffer fluctuations in oil pressure 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 1.7 bar to about 3.7 bar (absolute). A check valve (i.e., check valve) 77 located upstream of the oil accumulator 36 prevents back pressure from the accumulator 36 from acting on the reservoir or recovery chamber 70. Thus, the oil accumulator 36 can support the oil spurting pressure at the bearings 21, 31 due to oil splash conditions at the pump 60 and / or when the oil supply may be absent for a period of time at the inlet to the pump 60, for example, when the gyrostabilizer 1 experiences an extended period at a high precession angle (e.g., 70°) during a U-turn of the vessel. The oil accumulator 36 is preferably a bladder-type or piston-type oil accumulator.Downstream of the accumulator 36, the oil flow is divided between the conduit 50 to the upper spin bearing 21 and the conduit 51 to the upper spin bearing 21. Downstream of the accumulator 36, the oil flow is divided between the conduit 50 to the upper spin bearing 21 and the conduit 51 to the lower spin bearing 31 and the thrust bearing 32. It should be noted that the oil accumulator 36 can be located anywhere along the oil circuit 9 between the pump 75 and the branch of the oil line to the two conduits 50, 51.

[0042] The oil lubrication system 8 includes oil injection ports 54, 64, 67 at each of the upper and lower spin bearings 21, 31 and the thrust bearing 32 for targeted delivery or injection of oil O through the oil circuit 9. The oil flow rate is selected to achieve the desired exchange of heat generated in the bearings 21, 31, 32 with the oil. Thus, the oil lubrication system 8 also forms a cooling system for the bearings 21, 31, 32, with the oil acting as a coolant to remove heat from the bearings. In particular, the oil injection ports 54, 64 ensure that the oil O is applied to the inner rings of each of the rotation bearings 21, 31 and / or the rolling or sliding elements therein with sufficient velocity and pressure to mix with the boundary layer oil for effective lubrication and cooling. To this end, the oil circuit 9 includes heat exchangers 40, 41 for removing heat from the oil before it is delivered to the upper and lower bearings 21, 31. In this regard, the walls 72 of the reservoir or recovery chamber 70 may form or function as a heat exchanger for the oil O as it returns under gravity to the reservoir 70, optionally via a cooling medium provided in the walls 72 (e.g., in the form of a water jacket) and / or via fin elements (not shown) formed in the walls. The oil circuit 9 also includes at least one filter 38 for filtering the oil O before re-ejection at the outlets 54, 64, 67.

[0043] 2, it can be seen that the upper and lower bearings 21, 31 are provided with oil labyrinths 55, 62 around them to prevent oil O applied to the bearings 21, 31 from flowing to places where it should not, such as onto the flywheel 33 or onto the thrust bearing 32, which is cooled separately via line 65 and injection nozzle 67. These oil labyrinths 55, 62 direct the flow of oil via return lines or channels 58, 59, 68 to a reservoir or recovery chamber 70. As mentioned above, the reservoir or recovery chamber 70 is located within or on the housing so that oil supplied, circulated, or pumped to the first and second spin bearings 21, 31 and the thrust bearing 32 flows out of the respective bearings 21, 31, 32 through the respective oil labyrinths 55, 62 and returns to the reservoir 70 under gravity. The oil is preferably a synthetic oil with a vapor pressure of less than 40 mbar at 80°C.

[0044] The oil reservoir or recovery chamber 70 also functions as an oil degassing device but can also provide other functions, such as precipitating contaminants and / or passively cooling the oil. Oil drawn into the vacuum chamber 12 through the upper or lower shaft seals 33, 34 accumulates at the bottom of the vacuum chamber and collects in the oil scavenge cavity 80. However, pumping oil from the vacuum chamber's oil scavenge cavity 80 can again be difficult due to cavitation. A pump arrangement 81 utilizes the pressure differential between the vacuum chamber 12, the oil recovery chamber 60 (and spin bearing chambers 22, 24), and the atmosphere to pump oil from the vacuum chamber's oil scavenge cavity 80 to the oil recovery chamber 70. An upper valve 82, which can be a switchable one-way valve or a lockout valve, selectively connects the vacuum chamber's oil scavenge cavity 80 to a lubricant oil recovery (LOR) tank 83. A lower valve 84 selectively allows the LOR tank 83 to be connected to the oil recovery chamber 60 via an oil return conduit 88. Thus, the LOR tank 83 is normally switched open to the vacuum chamber 12 (i.e., at working pressure) for better oil recovery.

[0045] Advantages of the rotating disc pump 60 include the ability to run dry without damage, high temperature operation, ability to handle high viscosity fluids, virtually cavitation-free laminar flow, little maintenance, low manufacturing costs, low height, no break-in period required, ability to pump gas-liquid mixtures, suitable for high speed operation, and not interfering with the operation of the starting pump.

[0046] 6, there is shown a vessel S, such as a ship, yacht, or boat, including a gyrostabilizer assembly 1 according to the embodiment of the present disclosure described above. The gyrostabilizer assembly 1 is securely fixed to the hull H of the vessel S adjacent the keel K.

[0047] Referring to Figure 7, there is shown a hoisting system, such as a crane C, having a gyro stabilizer assembly 1 according to an embodiment of the present disclosure as described above. In this context, the gyro stabilizer assembly 1 is designed to be suspended from the hoisting system and operates to damp or suppress undesirable oscillatory rotations of a suspended cargo L, caused by, for example, wind gusts, during hoisting operations. A gyro stabilizer assembly 1 is provided for and / or mounted along each axis of stabilization required.

[0048] While specific embodiments of the present invention have been illustrated and described herein, it will be recognized by those skilled in the art that various alternative and / or equivalent embodiments exist. It should be understood that each exemplary embodiment is merely an example and is not intended to limit the scope, applicability, or configuration of the present invention in any way. Rather, the foregoing summary and detailed description will provide those skilled in the art with a convenient road map for implementing at least one exemplary embodiment. It will be understood that various changes can be made in the function and arrangement of elements described in the exemplary embodiments without departing from the scope as defined by the appended claims and their legal equivalents. In general, this application is intended to cover any adaptations or variations of the specific embodiments discussed herein.

[0049] In general, the present disclosure is intended to cover any adaptations or variations of the specific embodiments discussed herein. As an example, those skilled in the art will readily understand that the gyrostabilizer assembly 1 and systems of the present disclosure are not limited to being made from any particular material described in the specific embodiments. Rather, those skilled in the art will understand that a range of suitable materials exists, and they can readily select an appropriate material based on the known mechanical properties of that material that are suitable for use in the present disclosure. Because the present disclosure involves many fields of engineering, it is expected that the intended "person skilled in the art" will consist of a group or team of individuals with technical expertise and / or qualifications in one or more fields or disciplines, including mechanical engineering, marine engineering, and hydraulic engineering.

[0050] It is also understood that, as used herein, the terms “comprise,” “comprising,” “include,” “including,” “contain,” “containing,” “have,” “having,” and variations thereof, are intended to be understood in an inclusive (i.e., non-exclusive) sense unless the context indicates otherwise. Any process, method, device, apparatus, or system described herein is understood in a non-exclusive sense such that it is not limited to the described features, integers, portions, elements, or steps, but may include other features, integers, portions, elements, or steps not expressly described and / or inherent in such process, method, device, apparatus, or system. Furthermore, the indefinite articles “a” and “an,” as used herein, are intended to be understood to mean one or more unless expressly stated otherwise. Furthermore, the terms “first,” “second,” “third,” etc., are used merely as labels and are not intended to impose numerical requirements on the importance of their objects or to establish an order of importance. Additionally, references to positional terms such as "lower" and "upper" used in the above description should be taken in the context of the illustrated embodiments and should not be taken as limiting the invention to the literal interpretation of the terms, but rather as would be understood by one of ordinary skill in the art in the appropriate context. [Explanation of symbols]

[0051] 1 Gyro Stabilizer Assembly 5 Central opening 6 impeller 6a Flat solid disc 6b Annular or ring-shaped disc 7 Stems, bolts or fasteners 8 Oil Lubrication System 9 Oil Circuit 11 Flywheel 12 Vacuum chamber 13. Housing 14 Stub 15 Precession bearing 19 Flywheel shaft 20 Spin Axis 21 Upper bearing 31 Lower bearing 32 Thrust bearing 33 Upper shaft seal 34 Lower shaft seal 36 Oil accumulator 38 filters 39 Oil cooler 40 Heat exchanger 41 Heat exchanger 42 Cooling water supply line 44 Cooling water supply line 50 Oil supply line 51 Oil supply line 52 Electric Motor 53 Magnetic Coupling 54 Oil outlet 55 Oil Labyrinth 58 Oil return line 59 Oil return line 60 Pump 62 Oil Labyrinth 64 Oil outlet 65 Oil supply line 67 Oil outlet 68 Oil return line 70 Reservoir or Collection Chamber 71 Oil supply line 72 Reservoir or collection chamber wall 75 positive displacement pump 77 Check valve 79 Oil supply line V partial vacuum O Lubricating oil / oil W is the radial width of the annular disc t is the thickness of the annular disc S ship H Hull K Keel C. Hoisting equipment or crane L cargo

Claims

1. a housing defining a flywheel chamber for holding an operating pressure; a flywheel mounted within the flywheel chamber for rotation about a spin axis under operating pressure; a flywheel shaft having a flywheel mounted within the flywheel chamber; a first spin bearing chamber containing a first spin bearing and separated from the flywheel chamber by a first shaft seal; a second spin bearing chamber containing a second spin bearing and separated from the flywheel chamber by a second shaft seal; a bearing lubrication system; Equipped with the flywheel shaft is supported by a first spin bearing and a second spin bearing disposed at opposing end regions of the flywheel shaft; the bearing lubrication system includes a lubricant circuit for circulating lubricant to the first spin bearing and the second spin bearing from a reservoir or recovery chamber disposed in or adjacent to the second spin bearing chamber so as to collect lubricant under gravity from the first spin bearing and the second spin bearing; a pump is provided within said reservoir or collection chamber; the pump is coupled to the flywheel shaft and driven by the flywheel shaft to circulate the lubricant in the lubricant circuit to the first spin bearing and the second spin bearing.

2. the pump provided in the reservoir comprises a rotary disc pump, such as a hermetic rotary disc pump; 2. The gyrostabilizer assembly of claim 1, wherein the pump impeller is rotated by the flywheel shaft at a speed ranging from about 3,000 rpm to about 10,000 rpm, preferably from 5,000 rpm to 10,000 rpm.

3. 3. The gyrostabilizer assembly of claim 1, wherein the pump is disposed in a reservoir or collection chamber submerged in the lubricant.

4. the pump impeller includes at least two flat disks mounted in an axially aligned and generally parallel arrangement with respect to one another; 4. A gyrostabilizer assembly according to claim 1, wherein the two flat discs preferably comprise a first solid disc and a second annular disc having substantially the same outer diameter as the first disc.

5. The pump whether it is a generator rotor pump, vaned centrifugal pump, vane pump or positive displacement pump; or It consists of a two-stage pump, a rotary disc pump coupled to and driven by the flywheel shaft forming a first stage of the two-stage pump; 5. A gyrostabiliser assembly according to claim 1, wherein a vaned centrifugal pump forms the second stage of the two-stage pump.

6. the lubricant is an oil such as a synthetic oil, 6. A gyrostabiliser assembly according to any one of claims 1 to 5, wherein the oil preferably has a vapour pressure of less than 40 mbar at 80°C.

7. a lubricant circuit provided external to the housing, the lubricant circuit including an oil accumulator for storing lubricant and maintaining the pressure of the lubricant; 7. A gyrostabiliser assembly according to any one of claims 1 to 6, wherein the pressure is preferably between 1.2 bar and 3.2 bar.

8. the lubricant circuit includes a positive displacement pump external to the housing that circulates the lubricant from the reservoir or recovery chamber to the bearings and back, the positive displacement pump serving as a start, stop and boost pump; 8. A gyrostabiliser assembly according to any one of claims 1 to 7, wherein the positive displacement pump is preferably a vane pump, preferably magnetically coupled to a brushless electric motor.

9. the first spin bearing and the second spin bearing are provided with lubricant labyrinths around their peripheries to prevent lubricant supplied to the first spin bearing and the second spin bearing from flowing into the flywheel; 9. The gyrostabilizer assembly according to claim 1, wherein the lubricant labyrinth redirects the lubricant so that it flows through a flow path to the reservoir or recovery chamber.

10. 10. The gyrostabilizer assembly according to claim 1, wherein the bearing lubrication system includes lubricant outlets, in particular injection ports, for targeted release or injection of lubricant at each of the first spin bearing and the second spin bearing.

11. 11. The gyrostabilizer assembly according to claim 1, wherein the first spin bearing and the second spin bearing are constructed and arranged within the housing such that lubricant circulated through the first spin bearing and the second spin bearing flows out of each of the first spin bearing and the second spin bearing to return to the reservoir or recovery chamber under gravity.

12. the flywheel shaft is vertically mounted within the housing for rotation about a vertical spin axis; 12. The gyro stabilizer assembly of claim 1, wherein the first spin bearing and the second spin bearing comprise an upper spin bearing and a lower spin bearing, respectively.

13. an electric motor for driving rotation of the flywheel about the spin axis; 13. A gyro stabilizer assembly according to claim 1, wherein the electric motor is mounted on the outside of the housing and is coupled to the flywheel shaft via a magnetic coupling.

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

15. a housing defining a flywheel chamber for holding an operating pressure; a flywheel mounted within the flywheel chamber for rotation about a spin axis under operating pressure; a flywheel shaft having a flywheel mounted within the flywheel chamber; a first spin bearing chamber containing a first spin bearing and separated from the flywheel chamber by a first shaft seal; a second spin bearing chamber containing a second spin bearing and separated from the flywheel chamber by a second shaft seal; a bearing lubrication system; Equipped with the flywheel shaft is supported by a first spin bearing and a second spin bearing disposed at opposing end regions of the flywheel shaft; the bearing lubrication system includes a lubricant circuit for circulating lubricant to the first spin bearing and the second spin bearing from a reservoir or recovery chamber located at or adjacent to the second spin bearing; a lubricant circuit provided external to the housing, the lubricant circuit including an oil accumulator for storing lubricant and maintaining the pressure of the lubricant; The gyrostabilizer assembly is characterized in that the pressure is preferably equal to or greater than 1.7 bar and equal to or less than 3.7 bar.

16. a pump is provided within said reservoir or collection chamber; 16. The gyro stabilizer assembly of claim 15, wherein the pump is coupled to and driven by the flywheel shaft to circulate the lubricant in the lubricant circuit to the first spin bearing and the second spin bearing.

17. a pump is provided within said reservoir or collection chamber; the pump is coupled to and driven by the flywheel shaft to circulate the lubricant in the lubricant circuit to the first spin bearing and the second spin bearing; or 16. The gyro stabilizer assembly of claim 15, wherein the pump is separate from the flywheel shaft and driven by an electric motor to circulate the lubricant in the lubricant circuit to the first spin bearing and the second spin bearing.

18. the pump comprises an impeller; 18. A gyrostabilizer assembly as described in any one of claims 16 to 17, wherein the impeller includes at least two flat discs mounted in a generally parallel arrangement, preferably a first solid flat disc and a second annular flat disc axially aligned with the first disc and having the same outer diameter.

19. The gyroscopic stabilizer assembly of claim 18, wherein said impeller includes a plurality of disks mounted in an axially aligned, generally parallel arrangement relative to one another.

20. 20. The gyrostabilizer assembly according to claim 18 or 19, wherein the outer diameter of each disk of the impeller is within the range of about 100 mm to about 200 mm.

21. 21. A gyrostabilizer assembly according to claim 18, wherein the radial width of each annular disc is within the range of about 20% to about 40% of the outer diameter of the annular disc.

22. A watercraft, in particular a boat or motor yacht, comprising a gyro stabilizer assembly according to any one of claims 1 to 21, the gyro stabilizer assembly being fixed to the hull of the vessel.

23. A hoisting device comprising a gyro stabilizer assembly according to any one of claims 1 to 21, wherein the gyro stabilizer assembly is adapted to be suspended together with cargo.

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