Gyro Stabilizer Assembly

Abstract

The present invention relates to a gyrostabilizer assembly (1) for a marine vessel, comprising a housing (2) defining a chamber (3) for maintaining at least a partial vacuum, a flywheel (4) mounted in the chamber (3) for rotation about a spin axis (Z) under partial vacuum, a flywheel shaft (5) on which the flywheel (4) is supported and mounted in the housing for rotation of the flywheel about the spin axis (Z) and rotatably supported by a first spin bearing (6) arranged in one end region of the shaft (5) and a second spin bearing (7) arranged in an opposite end region of the shaft (5), and a lubrication system (8) configured to supply lubricant from a lubricant reservoir (9) to the spin bearings (6, 7). The reservoir (9) is arranged in or on the housing (2) and withdraws lubricant from the spin bearings (6, 7) under gravity, the first and second spin bearings (6, 7) being arranged in the housing (2) for operation under partial vacuum. The present invention also relates to a vehicle, in particular a watercraft, comprising the gyrostabilizer assembly (1).

Description

[Technical Field]

[0001] The present invention relates to a gyro stabilizer assembly, and more particularly to a lubrication system for bearings of a gyro stabilizer assembly.

[0002] The gyrostabilizer assemblies of the present invention are typically designed for use on marine vessels, and it will be convenient to describe the invention in this exemplary context. However, it will be understood that the gyrostabilizer assemblies of the present invention are not limited to such particular embodiments and may be designed for use in many other applications, such as other fixed and floating structures, other vehicles, and / or camera mounts. [Background technology]

[0003] The following discussion of background herein should in no way be taken as an admission that such background is prior art or that such background is well known or forms part of the common general knowledge in the field in Australia or elsewhere.

[0004] The structure and operation of gyroscopic stabilizer assemblies for marine vessels are generally well understood, and these devices are increasingly being adopted on commercial and recreational vessels. Gyroscopic stabilizer assemblies typically include a rotating flywheel mounted on a gimbal frame that allows two of three rotational degrees of freedom, with the frame rigidly mounted within the vessel. Due to the specific manner in which the flywheel is constrained in rotational motion, the angular momentum of the rotating flywheel, combined with the precessional oscillation of the flywheel, can generate a large, time-varying torque that directly opposes the dynamic rolling motion of the vessel caused by wind and / or waves. The rolling motion of the vessel, by default, couples with the angular momentum of the flywheel, causing an oscillating precession. This, in turn, combines with the angular momentum to generate a stabilizing torque that directly opposes undesirable rotational motion of the vessel (such as wave-induced rolling motion). By configuring the gimbal in a specific manner, a roll stabilization device is created that utilizes the naturally occurring physics of gyrodynamics, requiring no further intervention to function. An example of a gyro stabilizer assembly for a watercraft is described in the applicant's co-pending Australian patent application AU2017216483A1, the contents of which are incorporated herein by direct reference in their entirety.

[0005] Due to the high speed of the outer rim of a gyrostabilizer flywheel, gimbal frames often include a chamber surrounding the flywheel that is evacuated to allow the flywheel to rotate within 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, improving efficiency. Spin bearings used to position and support the flywheel around its axis of rotation are subjected to both high loads and high rotational speeds, generating heat and noise. Spin bearings and spin motors are typically placed within a vacuum chamber to avoid problems associated with sealing the vacuum chamber where the spin shaft exits. However, having spin bearings within a vacuum chamber can make bearing lubrication and cooling difficult. Cooling the interior of the spin bearings and flying wheel shaft can be particularly challenging because they rotate and cannot be easily cooled by contact with a coolant jacket.

[0006] Co-pending Australian patent application AU2017216483A1 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 oil replacement of heat generated by the bearings. Oil lubrication systems are desirable because they reduce noise, extend bearing life, and remove heat from the bearing's interior. In this system, oil is pumped from a sump by one or more scavenge pumps, in an arrangement similar to the "drive sump" pump arrangement in racing cars. To operate the scavenge pumps, a rotating shaft seal on the flywheel shaft separates the upper and lower bearing chambers from the vacuum chamber surrounding the flywheel. One seal is located below the upper bearing chamber and another seal is located above the lower bearing chamber, and the upper and lower bearing chambers are manifolded together by a drain line between them. This configuration allows the flywheel to rotate at a pressure low enough that air resistance is greatly reduced or eliminated in a partial or near vacuum, while the bearing housing (to which it is integrated to operate at the same pressure) operates at a pressure high enough for the scavenge pump to effectively supply oil to the spin bearing.

[0007] However, the configuration described in AU2017216483A1 has the disadvantage that it requires a dual vacuum pressure management system for the vacuum chamber and the bearing chamber, and the rotating shaft seal components are subject to rotational resistance due to high contact surface speeds, which leads to wear and costs associated with maintenance and / or subsequent replacement, as well as higher power requirements to maintain the desired flywheel rpm.

[0008] It would therefore be desirable to provide a novel gyrostabilizer arrangement that substantially overcomes or ameliorates one or more of the above-mentioned disadvantages. In this regard, it would be desirable to provide a novel, simpler gyrostabilizer arrangement that employs an oil lubrication system to lubricate and cool the bearings. Summary of the Invention

[0009] According to one broad aspect, the present invention provides a method for manufacturing a semiconductor device comprising: a housing defining a chamber for maintaining an operating pressure; a flywheel mounted within the chamber that rotates about a spin axis under operating pressure; a flywheel shaft on which a flywheel is supported and which is mounted within the housing by first and second spin bearings disposed at opposite end regions of the shaft for rotation of the flywheel about a spin axis; a lubrication system for the first and second spin bearings configured to supply or circulate lubricant from a reservoir to the first and second spin bearings; A gyro stabilizer assembly is provided. The lubricant reservoir is disposed within or on the housing and recovers lubricant from the first and second spin bearings under gravity. The first and second spin bearings are disposed within the housing for use / operation under operating pressure or under operating pressure (e.g., when operating pressure is applied only during use).

[0010] Thus, the present invention provides a significantly simpler configuration or structure of a gyrostabilizer assembly in which a rotary shaft seal is not required to separate or isolate the spin bearing from the operating pressure of the flywheel chamber. This has the advantage of eliminating the need for a dual vacuum pressure management system, simplifying the configuration by reducing the number of components and the likelihood of failure, thereby improving the reliability and robustness of the gyrostabilizer assembly. In particular, this configuration eliminates the need for a rotary shaft seal, which is prone to wear, saving the time and expense of maintaining and / or replacing the seal. Because shaft seals typically generate significant rotational resistance, the new configuration also reduces the power required to maintain the flywheel's rpm and removes the limitations on flywheel rpm imposed by the shaft seal's ability to withstand high contact surface speeds.

[0011] In a preferred embodiment, the first and second spin bearings are constructed and arranged within the housing such that lubricant supplied, circulated, or pumped to the first and second bearings is discharged from the respective bearings to return to the reservoir under gravity. In this regard, it will be understood that the lubricant is a liquid under operating pressures and temperatures. The lubricant typically comprises an oil, such as a synthetic oil.

[0012] The term "spin bearing" as used throughout this document will be understood as a reference to a bearing designed to mount or support a flywheel shaft for rotation, preferably free rotation, about a spin axis. The term "spin bearing" will therefore be understood as a rotation bearing and will be understood to include a variety of rotation bearing designs, including hydrodynamic bearings and rolling bearings.

[0013] In a preferred embodiment, the first and second spin bearings are configured as rolling bearings, for example, with an inner ring of the rolling bearing rigidly attached to the flywheel shaft and rotating with the shaft, and an outer ring rigidly fixed to the housing. Alternatively, the first and second spin bearings may be configured as plain bearings, for example, plain fluid bearings.

[0014] In a preferred embodiment, the operating pressure is at least a partial vacuum so that the chamber in which the flywheel is mounted forms a vacuum chamber. Placing the chamber containing the flywheel and bearings in at least a partial vacuum (e.g., less than 0.5 bar, preferably less than 0.25 bar) is preferred because it reduces the aerodynamic drag of the flywheel, reducing the power required to maintain the flywheel's rpm while also reducing the heat generated by air resistance on the rotating flywheel. In this way, all of the vacuum chambers within the gyrostabilizer assembly form a single chamber operating at one vacuum pressure. The vacuum pressure must be low enough to significantly reduce or eliminate air resistance and the resulting heat generation. Testing and experience have shown that the operating pressure should preferably be approximately 0.2 bar or less.

[0015] In a preferred embodiment, the lubrication system includes a lubricant circuit in which lubricant is circulated from a reservoir to the bearings and then returned to the reservoir. In this regard, the lubrication system includes at least one pump that circulates lubricant from the reservoir to the first and second spin bearings. The at least one pump is preferably in the form of a positive displacement pump, and the pump is desirably configured so that the lubricant in the reservoir provides a positive pressure head at the pump inlet. To this end, the pump may be positioned to be submerged in the lubricant in the reservoir. Alternatively, the pump may be positioned in or on a housing, with the pump inlet in fluid communication with the reservoir at a level spaced below the level of the lubricant held in the reservoir. This configuration significantly simplifies the lubrication system known from co-pending application AU2017216483A1. That is, rather than employing both a sump or recovery tank for degassing the lubricant (e.g., oil) and a separate reservoir for the degassed oil from the sump, along with both an oil return pump for returning the oil from the sump to the reservoir and a feed pump for supplying oil from the reservoir to the spin bearings, the inventive arrangement can eliminate the need for a separate tank for degassing the oil prior to the inlet of the feed pump, and therefore the need for a separate return pump. That is, the oil degassing is preferably performed in a reservoir that also forms the oil sump or recovery tank. That is, the reservoir may function as a settling tank for oil contaminants, a degassing tank, and a cooling tank.

[0016] In a preferred embodiment, the lubrication system includes lubricant supply outlets, specifically lubricant injection ports, that supply or inject lubricant targeted at each of the first and second bearings. Therefore, the lubrication system may include an "oil jet" system. The oil flow rate is preferably selected to provide both lubrication and heat exchange with the oil generated in the bearings. Injecting oil through the injection ports allows the oil to strike the rolling or sliding elements of the spin bearings with sufficient velocity and pressure to mix with the oil in the boundary layer, providing effective lubrication and cooling. Therefore, the pump for supplying lubricant (i.e., oil) from the reservoir to the first and second spin bearings is designed to prime and provide the backpressure necessary to drive the oil through the oil supply outlet at the required velocity. By carefully selecting a pump that provides the required pressure and flow rate, the pump can be positioned and sized to 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 supply outlet.

[0017] In a preferred embodiment, the lubrication system may form a cooling system for the spin bearings. In particular, the oil may act as a coolant to carry heat away from the first and second bearings. For this purpose, the oil circuit preferably includes one or more heat exchangers for removing heat from the oil before it is supplied to the first and second spin bearings. In this regard, the housing wall may form a heat exchanger for the oil when it returns to the reservoir under gravity and / or when it is circulated from the reservoir to the spin bearings, optionally with a cooling medium provided in the housing wall (e.g., a water jacket) and / or with fin elements formed on the wall. This heat can be discharged (e.g., overboard) as heated cooling water. Degassing the lubricant (oil) at the time of supply to the bearings is beneficial because it ensures that the supply port functions to provide a directional jet with sufficient velocity to penetrate the boundary layer for necessary mixing and improves heat transfer through the heat exchanger. Oil typically needs to be filtered before being re-injected.

[0018] The gyroscope assembly of the present invention contemplates both horizontal and vertical orientations of the flywheel shaft, each of which presents lubrication challenges in terms of supplying lubricant (e.g., oil) to each spin bearing and recovering and reapplying the lubricant.

[0019] In a preferred embodiment, the flywheel shaft is mounted in a generally vertical orientation within the housing so that it rotates about a generally vertical spin axis. The first and second bearings thus form the upper and lower spin bearings, respectively. A vertical flywheel shaft is preferred because it allows the housing to be configured as a pendulum with a natural stable point near the vertical. This eliminates the need for an extra mechanism to ensure that the precession angle of the gyroscope assembly remains "centered" near the middle of its stroke. Oil returning from the upper and lower bearings is directed to a common reservoir or sump in the lower region or base of the housing below the vacuum chamber. The oil in the reservoir may be scavenged and then circulated by at least one pump located in or adjacent to the reservoir.

[0020] In a preferred embodiment, the lubrication system includes two or more outlet ports from the reservoir, located at different positions and in fluid communication with the pump inlet, to ensure lubrication of the spin bearings regardless of the operating position of the gyroscope assembly. That is, the outlets from the reservoir can be positioned so that the lubricating oil is always effectively pumped or circulated, even if the oil in the reservoir shifts as the gyroscope assembly swings or moves (e.g., as a pendulum) during operation. For example, if the housing swings or rotates ±70 degrees during operation, the oil in the reservoir may leave one outlet port. By providing two or more outlet ports in different positions (e.g., on different sides of the reservoir) and communicating them with the pump inlet, at least one outlet port from the reservoir is always flooded, ensuring effective oil circulation.

[0021] In a preferred embodiment, the gyroscope assembly includes a member, such as a disk-shaped member, firmly or rigidly attached to the flywheel shaft for rotation therewith and positioned below the upper spin bearing to receive oil that falls from the upper spin bearing under gravity. This member is therefore designed to distribute the oil radially outward onto the inner wall of the housing surrounding the flywheel chamber and return it to the reservoir under gravity. In this regard, the high speed rotation of the disk member, which rotates with the flywheel shaft, accelerates the oil radially outward by centrifugal force, reaching the inner wall of the housing and causing it to fall under gravity into the reservoir. Alternatively, or in addition, the flywheel may include one or more channels extending through the flywheel, e.g., near the shaft, that define channels for collecting oil that falls from the upper spin bearing under gravity and directing it back to the reservoir. Due to the need for rotational stability of the flywheel, it is desirable for the multiple channel flow paths to be identical and symmetrically arranged about the spin axis. However, due to the high stresses imposed on the flywheel, such channels may be impractical in some cases. Without channels through the disk member and / or flywheel, lubricating oil from the upper spin bearing would flow directly down onto the flywheel, over the outer rim of the flywheel, and radially outward into the housing wall and into an oil reservoir at the base of the housing.

[0022] In a preferred embodiment, the gyroscope assembly includes a spin motor for driving the 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 chaff via either a magnetically sealed coupling or a shaft connection. If a shaft connection is required for a spin motor mounted outside the chamber, it also requires a rotary shaft seal. However, the advantage of this approach is that the shaft connecting the spin motor to the flywheel shaft only needs to transmit a relatively small torque and can therefore be of a relatively small diameter. This limits the speed of the seal's contact surface (reducing circumference at a given rotational speed reduces speed), greatly expanding the number of rotations possible before the seal capacity is reached and reducing the seal's rotational resistance. In contrast, current rotary shaft seals are located on the flywheel shaft, which must withstand the gyroscopic torque that fully reverses with each rotational speed cycle. This results in a very large shaft diameter and circumference, which increases the contact surface speed and wear, creating technical challenges in extending seal life.

[0023] According to another aspect, the present invention provides a gyroscopic stabilizer assembly for a marine vessel, the assembly comprising: a housing defining a chamber for maintaining at least a partial vacuum; a flywheel mounted within the chamber and configured to rotate about a spin axis under the partial vacuum; a flywheel shaft on which the flywheel is supported and mounted within the housing for rotation of the flywheel about the spin axis, the flywheel shaft being rotatably supported by a first rotary bearing disposed at one end region of the shaft and a second rotary bearing disposed at the opposite end region of the shaft; and a lubrication system configured to supply lubricant from a lubricant reservoir to the rotary bearings. The reservoir is disposed within or on the housing and recovers lubricant from the bearings under gravity. The first and second rotary bearings are disposed within the housing for use / operation under partial vacuum or under partial vacuum (e.g., when a vacuum is applied only during use).

[0024] As noted above, because the structure and operation of marine gyro stabilizers are generally fairly well understood, this specification does not aim to provide a detailed description of all of the components of a gyro stabilizer 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.

[0025] According to another aspect, the present invention provides a watercraft, such as a boat, including or incorporating an inventive gyro stabilizer assembly according to any of the above embodiments.

[0026] The term "gyrostabilizer assembly" as used throughout this specification will be understood to refer to a gyrostabilizer assembly device or gyrostabilizer unit that may be incorporated into or installed on a vehicle such as a watercraft, or any other device that is subject to undesirable rotational motion (such as rolling motion due to waves), to counteract and / or reduce such undesirable motion.

[0027] For a more complete understanding of the present invention and its advantages, exemplary embodiments of the invention will be described in more detail in the following description with reference to the accompanying drawings, in which like reference numerals designate like parts and in which: [Brief explanation of the drawings]

[0028] [Figure 1] FIG. 1 is a schematic cross-sectional side view of a gyrostabilizer assembly according to a preferred embodiment of the present invention. [Figure 2] FIG. 2 is a schematic cross-sectional side view of a gyrostabilizer assembly according to another preferred embodiment of the present invention. [Figure 3] FIG. 3 is a schematic cross-sectional side view of a gyrostabilizer assembly according to a further preferred embodiment of the present invention. [Figure 4] FIG. 4 is a schematic side cross-sectional view of a gyrostabilizer assembly according to yet another preferred embodiment of the present invention. [Figure 5] FIG. 5 is a schematic cross-sectional side view of a gyrostabilizer assembly according to yet another preferred embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0029] 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 and many of the attendant advantages of the invention will be readily appreciated as the same become better understood by reference to the following detailed description.

[0030] 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 to promote 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.

[0031] Referring to Figure 1 of the drawings, a gyrostabilizer assembly 1 according to a preferred embodiment is shown. The gyrostabilizer assembly 1 includes a housing 2 defining a vacuum chamber 3 for maintaining an operating pressure of a partial vacuum V (e.g., about 0.2 bar or less), and a flywheel 4 integral with or fixed to a generally vertically oriented flywheel shaft 5 mounted within the vacuum chamber 3 for rotation about a generally vertical spin or rotation axis Z under the operating pressure. The flywheel shaft 5, to which the flywheel 4 is fixed and supported, is attached to the housing 2 via upper and lower rotation bearings 6, 7 (also referred to as "spin bearings") located at opposite end regions of the shaft 5 for rotation of the flywheel 4 about the spin axis Z. In this embodiment, the upper and lower bearings 6, 7 are in the form of rolling bearings in which rolling elements (e.g., steel balls) are held and movable between an inner ring fixed firmly to the shaft 5 and an outer ring fixed firmly to the housing 2. The vertical orientation of the flywheel shaft 5 and spin axis Z allows the housing 2 to be set up or mounted as a pendulum about pivot axis X with a natural stability point near vertical. As a result, no mechanism is required to keep the precession angle of the gyroscope assembly 1 centered near the middle of its mid-stroke. The gyroscope assembly 1 includes an electric drive motor or spin motor (not shown) mounted in or on the housing 2 for driving the rotation of the flywheel 4 about spin axis Z.

[0032] The gyrostabilizer assembly 1 further includes a lubrication system 8 (oil-based) for the bearings 6,7 configured to circulate oil O from an oil reservoir 9 to each of the upper and lower bearings 6,7. The lubrication system 8 provides an oil circuit 10 through which the oil O is circulated from the oil reservoir 9 to each of the spin bearings 6,7 and then returned to the reservoir 9. The oil circuit 10 may include lines or conduits both internal and / or external to the housing 2, through which the oil O is pumped or supplied from the oil reservoir 9 to each of the bearings 6,7. The upper and lower bearings 6,7 are configured and arranged within the housing 2 such that the oil O circulated or pumped to the bearings 6,7 is drained from the respective bearings 6,7 to return to the reservoir 9 under gravity. In this regard, the lubrication system 8 includes at least one pump 11 for circulating or pumping oil from the reservoir 9 to the upper and lower bearings 6,7. At least one pump 11 is a positive displacement pump, such as a gear pump, and is arranged so that oil O in reservoir 9 provides a positive pressure head at pump inlet 12. To this end, the pump is disposed in or on housing 2, with pump inlet 12 in fluid communication with reservoir 9 at a level spaced below the level L of oil held in reservoir 9. The vertical orientation of spin axis Z means that oil O returning from upper and lower bearings 6, 7 is directed to a common reservoir 9 (or sump). Reservoir 9 is disposed at base 13 of housing 2 below vacuum chamber 3, so that upper and lower bearings 6, 7 provided within housing 2 recover oil under operating pressure V by gravity via return lines or conduits 14 from the bearings 6, 7. Thus, vacuum chamber 3 is a single chamber operating at a single pressure V. This not only reduces the aerodynamic drag on the flywheel 4, reducing both the power required to maintain the flywheel rotation speed (rpm) and the heat generated by air resistance against the rotating flywheel 4, but also results in a gyrostabilizer assembly 1 with a simpler configuration, in which no rotating shaft seals are required to isolate the upper and lower spin bearings 6, 7 from the operating pressure V of the flywheel chamber 3.

[0033] 1, it will be seen that the flywheel 4 has a channel 15 extending through the flywheel 4 adjacent the shaft 5 which provides a flow path for collecting oil that falls from the upper spin bearing 6 under gravity and directing it back to the reservoir 9. Without such a channel 15 extending through the flywheel 4, the lubricating oil from the upper spin bearing 6 would fall directly onto the flywheel 4 and, under centrifugal action, flow radially outward over the outer rim of the flywheel and into the oil reservoir 9 in the base 13 of the housing 2.

[0034] The oil lubrication system 8 includes oil injection ports 16 that target or inject oil into each of the upper and lower spin bearings 6, 7 via at least one pump 11. The oil flow rate is selected to provide both lubrication and the exchange of heat generated in the bearings 6, 7 with the oil. Thus, the oil lubrication system 8 also forms a cooling system for the spin bearings 6, 7, with the oil acting as a coolant to carry heat away from the bearings. In particular, the injection of oil via the injection ports 16 ensures that the oil is directed at the rolling elements of the bearings 6, 7 with sufficient velocity and pressure to mix with the oil in the boundary layer and provide effective lubrication and cooling. To this end, the oil circuit 10 typically includes a heat exchanger that removes heat from the oil before it is delivered to the upper and lower bearings 6, 7. In this regard, the wall 17 of the housing 2 surrounding the chamber 3, against whose inner surface the oil is "thrown" by the centrifugal action of the flywheel 4, may optionally form or act as a heat exchanger for the oil O as it returns under gravity to the reservoir 9, via a cooling medium provided in the wall 17 (e.g. in the manner of a water jacket) and / or fin elements (not shown) formed in the wall 17. The oil circuit 10 also typically includes one or more filters (not shown) for filtering the oil before it is re-injected at the outlets 16.

[0035] Referring to FIG. 2 of the drawings, a gyrostabilizer assembly 1 according to another preferred embodiment is shown. This embodiment has most of the same features as the gyrostabilizer assembly 1 shown in FIG. 1. However, in this embodiment, the channel 15 penetrating the flywheel 4 is not provided, thereby ensuring greater rotational stability of the flywheel 4. Instead, a disk member 18 is rigidly attached to the flywheel shaft 5 for rotation therewith, above the flywheel 4 but below the upper spin bearing 6, to receive oil that flows down from the upper bearing 6 under gravity. In this manner, the disk member 18 distributes ("flys") the oil radially outward to the inner wall 17 of the housing 2 surrounding the flywheel chamber 3, and operates to return the oil to the reservoir 9 under the action of gravity. In this regard, the high rotational speed of the disk member 18 rotating with the flywheel shaft 5 causes the oil to be accelerated radially outward by centrifugal force, reach the inside of the wall 17 of the housing 2, and flow down under gravity into the reservoir 9.

[0036] Referring now to FIG. 3 of the drawings, a further preferred embodiment of the gyrostabilizer assembly 1 is shown. This embodiment has most of the same features as the gyrostabilizer assembly 1 shown in FIG. 2, but does not include a disk-shaped member 18 for distributing oil radially outward toward the wall 17 surrounding the flywheel chamber 3. Instead, in this case, the flywheel 4 itself acts to "fly" the oil O toward the wall 17. Another difference from the second embodiment of FIG. 2 is the fact that, instead of rolling bearings, the upper and lower rolling bearings 6, 7 are provided as plain hydrodynamic bearings. These bearings are simpler in construction than rolling bearings and typically offer greater durability at lower resistance costs. Oil is supplied to the upper and lower plain hydrodynamic spin bearings via lines or conduits in the oil circuit 10, as in the embodiments of FIGS. 1 and 2.

[0037] Referring to Figure 4 of the drawings, yet another preferred embodiment of the gyro stabilizer assembly 1 is shown. This embodiment differs from the embodiment shown in Figure 3 in that the flywheel 4 has a substantially uniform cross-section (i.e., there is no reduced thickness adjacent the flywheel shaft 5). This configuration facilitates a heavier flywheel 4 for a given diameter, which increases angular momentum at the expense of reduced efficiency. This is useful when the gyro stabilizer assembly 1 is size-constrained (i.e., has a diameter constraint), such as when it is incorporated into an outboard motor. This configuration also prevents oil from collecting on the upper side of the flywheel when the gyro stabilizer assembly 1 is not operating (i.e., is stopped).

[0038] Finally, referring now to FIG. 5 of the drawings, a gyrostabilizer assembly 1 according to yet another preferred embodiment is shown. This embodiment differs from the embodiment shown in FIG. 2 in that the flywheel shaft 5 does not have disk members 18 and is hollow or has a central channel 19 for receiving lubricating oil O from the oil circuit 10 to cool the inner rings of the upper and lower bearings 6, 7. In this regard, as described with reference to FIG. 1, the upper and lower spin bearings 6, 7 in this embodiment are rolling bearings in which rolling elements (e.g., steel balls) are held and movable between an inner ring firmly fixed to the shaft 5 and an outer ring firmly fixed to the housing. Therefore, oil circulating through the central channel 19 of the flywheel shaft 5, for example via the injection ports 16, can act to cool the inner rings firmly fixed to the shaft 5.

[0039] While specific embodiments of the present invention have been illustrated and described herein, those skilled in the art will recognize 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 be limiting in any way in scope, applicability, or configuration. 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, and it will be understood that various changes can be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope as defined in 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.

[0040] It will also be understood that, as used herein, the terms "comprise," "comprising," "include," "including," "contain," "containing," "have," and "having," and variations thereof, unless the context dictates otherwise, are intended to be understood in an inclusive (i.e., non-exclusive) sense such that the processes, methods, devices, apparatuses, or systems described herein are not limited to the described features, wholes, parts, elements, or steps, but may include other features, wholes, parts, elements, or steps that are not expressly described and / or that are inherent in such processes, methods, devices, apparatuses, or systems. Furthermore, the terms "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 or establish an order of importance on their objects. Additionally, references to positional terms such as "lower" and "upper" used in the above description are to be taken in the context of the illustrated embodiments and not 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]

[0041] 1 Gyro Stabilizer Assembly 2. Housing 3. Vacuum chamber 4 Flywheel 5 Flywheel shaft 6 Upper bearing 7 Lower bearing 8 Lubrication System 9 Reservoir 10 Oil circuit 11 Pump 12 Pump inlet 13 Housing base 14 Return line or conduit 15 channels 16 Nozzle 17 Housing Wall 18 Disk-shaped member 19 Channel in the shaft Z shaft rotation or spin axis V partial vacuum X Pivot Axis O Oil L Reservoir oil level

Claims

1. A housing defining a chamber for maintaining an operating pressure of less than 0.5 bar; a flywheel mounted within the chamber that rotates about a spin axis under the operating pressure; a flywheel shaft on which the flywheel is supported and mounted within the housing by first and second spin bearings located at opposite end regions of the flywheel shaft for rotation of the flywheel about the spin axis; a lubrication system for the first and second spin bearings configured to supply lubricant from a reservoir to the first and second spin bearings; Equipped with the reservoir is disposed within or on the housing so as to be at an operating pressure in use, and recovers the lubricant from the first and second spin bearings under gravity; the first and second spin bearings are disposed within the housing to receive the operating pressure; the lubrication system includes a jet of lubricant provided for each of the first and second spin bearings, the jet of lubricant being aimed at the first and second spin bearings.

2. the lubrication system includes at least one pump for circulating the lubricant to the first and second spin bearings; The gyro stabilizer assembly of claim 1 , wherein the at least one pump is configured such that the lubricant in the reservoir provides a pressure head at an inlet of the pump.

3. 3. The gyrostabilizer assembly of claim 2, wherein the pump is positioned so as to be submerged in the lubricant in the reservoir, or the pump is positioned in or on the housing with the inlet of the pump in fluid communication with the reservoir at a level spaced below the level of the lubricant held in the reservoir.

4. 4. The gyrostabilizer assembly according to claim 2, wherein the pump is a positive displacement pump.

5. Each of the first and second spin bearings includes a rolling element or a sliding element; 5. The gyrostabilizer assembly according to claim 1, wherein each injection port is configured to supply or inject lubricant directly toward the rolling elements or the sliding elements in each of the first and second spin bearings.

6. 6. The gyrostabilizer assembly according to claim 1, wherein the first and second spin bearings are constructed and arranged within the housing such that lubricant circulated through the first and second spin bearings is discharged from the respective spin bearings and returned to the reservoir under gravity.

7. the flywheel shaft is mounted in a generally vertical orientation within the housing for rotation about a generally vertical spin axis; 7. The gyro stabilizer assembly according to claim 1, wherein the first and second bearings comprise an upper spin bearing and a lower spin bearing, respectively.

8. 8. The gyro stabilizer assembly of claim 7, further comprising a disk-shaped member rigidly attached to the flywheel shaft for rotation therewith, positioned below the upper spin bearing to receive lubricant that drains from the upper spin bearing, and distributing the lubricant radially outward onto an inner wall of the housing surrounding the chamber for return under gravity to the reservoir.

9. 9. A gyrostabilizer assembly according to any one of claims 1 to 8, wherein the housing wall forms a heat exchanger for the lubricant as it returns to the reservoir under gravity, optionally by means of a cooling medium provided in the wall and / or optionally by means of fin elements formed in the wall.

10. 10. A gyrostabilizer assembly according to claim 1, further comprising a spin motor for driving rotation of the flywheel about the spin axis, the spin motor being mounted within the chamber.

11. 10. A gyrostabilizer assembly as described in any one of claims 1 to 9, further comprising a spin motor for driving rotation of the flywheel about the spin axis, the spin motor being mounted outside the chamber and coupled to the flywheel shaft by either a magnetically sealed coupling or a shaft connection.

12. 12. A gyrostabilizer assembly according to any preceding claim, wherein the operating pressure is a partial vacuum such that the chamber in which the flywheel is mounted forms a vacuum chamber.

13. 13. The gyrostabilizer assembly according to claim 1, wherein the lubricant is liquid under operating pressure and temperature and comprises a synthetic oil.

14. a housing defining a chamber for maintaining at least a partial vacuum; a flywheel mounted within the chamber that rotates about a spin axis under a partial vacuum; a flywheel shaft on which the flywheel is supported and mounted within the housing for rotation of the flywheel about a spin axis, the flywheel shaft being rotatably supported by a first rotary bearing located at one end region of the flywheel shaft and a second rotary bearing located at an opposite end region of the flywheel shaft; a lubrication system configured to supply lubricant from a lubricant reservoir to the first and second rotary bearings; Equipped with the lubricant reservoir is disposed within or on the housing to operate under a partial vacuum and recover lubricant from the first and second rotary bearings under gravity; the first and second rotary bearings are disposed within the housing for operation under a partial vacuum; a lubrication system for supplying lubricant to the first and second rotary bearings through a nozzle provided for each of the first and second rotary bearings;

15. Each of the first and second rotary bearings includes a rolling element or a sliding element, 15. The gyrostabilizer assembly according to claim 14, wherein each injection port is configured to supply or inject lubricant directly to the rolling elements or the sliding elements in each of the first and second rotary bearings.

16. A watercraft, in particular a boat or motor yacht, comprising a gyrostabiliser assembly according to any one of claims 1 to 15.

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