Gyroscope for Anti-roll stabilizer and gyroscopic effect Anti-roll stabilizer

Abstract

A gyroscope (1) for an anti-roll stabilizer for a seacraft is described, comprising: a flywheel (3), mounted on a shaft (4) having a first end (41) and a second end (42) which is opposite to said first end (41) wherein the ends of the shaft (4) are supported by pairs of angular contact ball bearings arranged in tandem, with an overall "O" configuration, and an adjustable preload member (7) to axially push the outer rings (832, 842) of the angular contact ball bearings (83, 84) and thereby to preload all the bearings of the gyroscope (81, 82, 83, 84).

Description

[0001] GYROSCOPE FOR ANTI-ROLL STABILIZER AND GYROSCOPIC EFFECT ANTI-ROLL

[0002] STABILIZER

[0003] DESCRIPTION

[0004] Related applications

[0005] This application claims the priority of the Italian patent application 102023000027381, filed on December 20, 2023, and the Italian patent application 102023000027387, filed on December 20, 2023, the content of which is fully incorporated herein.

[0006] Technical Field

[0007] A gyroscope for an anti-roll stabilizer for a seacraft is described herein below.

[0008] A gyroscopic effect anti-roll stabilizer, of the two-degrees-of-freedom type, which comprises such gyroscope is also described.

[0009] Background art

[0010] Anti-roll stabilizers are devices used for reducing the rolling of seacrafts.

[0011] Gyroscopic effect anti-roll stabilizers are devices installed inside the hulls of the seacrafts, typically near the keel of the seacraft.

[0012] Gyroscopic effect anti-roll stabilizers exploit the physical principle of the gyroscope, whereby a rotating mass opposes an external force which attempts to deviate the initial rotational axis thereof.

[0013] The gyroscope of an anti-roll stabilizer comprises a flywheel mounted on a shaft, actuated by an electric motor, which is supported by rolling bearings (usually ball bearings).

[0014] Extremely briefly, the gyroscope, being able to oscillate with respect to two axes, creates an action of contrast to the oscillations whereto the seacraft is subjected and, in particular, to rolling.

[0015] WO2019224322 discloses a gyroscope for an anti-roll stabilizer for a seacraft, comprising a dismountable container housing a flywheel, which is attached to a shaft mounted between a first group of bearings and a second group of bearings.

[0016] An electric motor, of the type having an internal rotor and an external stator, is provided to rotate the shaft and thereby the flywheel.

[0017] The motor is positioned externally to the two groups of bearings.

[0018] W02022234080 discloses a gyroscope for an anti-roll stabilizer of a seacraft, comprising a dismountable container housing a flywheel, attached to a shaft mounted between a first group of bearings and a second group of bearings.

[0019] An electric motor, of the type having an external rotor and an internal stator, which is positioned in an intermediate positioned between the two groups of bearings, is provided to rotate the flywheel.

[0020] The currently known gyroscopic effect anti -roll stabilizers have some drawbacks.

[0021] For example, they are subject to frequent periodic operations for maintenance and replacement of the worn components, such as the rolling bearings. Summary

[0022] A gyroscope for an anti-roll stabilizer for a seacraft, which is able to at least partially overcome the problems of the prior art and in particular the above mentioned problems, is described.

[0023] In particular a gyroscope for an anti-roll stabilizer for a seacraft, which allows the operations for the maintenance and, in particular, the replacement of the bearings to be facilitated is described.

[0024] A further objective of the invention is to propose a solution that allows the costs of manufacturing gyroscopes for anti-roll stabilizers for a seacraft to be reduced.

[0025] These and other objectives are achieved by means of a gyroscope for an anti-roll stabilizer in accordance with the description and drawings.

[0026] Brief description of the drawings

[0027] A possible embodiment of a gyroscope for an anti-roil stabilizer tor a seacraft is described herein below with reference to the attached sheets of drawings in which:

[0028] Figure 1 is a schematic perspective view of a gyroscopic effect anti-roil stabilizer;

[0029] Figure 2 is a sectional view of a gyroscope;

[0030] Figure 3 is an enlarged view of a portion of the gyroscope in Figure 2 with respect to a first section plane;

[0031] Figure 4 is an enlarged view of the same portion of the gyroscope as in Figure 3 with respect to a second section plane;

[0032] Figure 5 is an enlarged longitudinal sectional view of another portion of the gyroscope in Figure 2;

[0033] Figure 6 is a hydraulic diagram relating to the preload of the gyroscope bearings;

[0034] Figure 7 is the same view as in Figure 2 and highlights the “O” configuration of the thrust axes of the bearings;

[0035] Figure 8 is an exploded view relating to the flywheel and the shaft of the gyroscope flywheel;

[0036] Figure 9 is a sectional view of a first detail of the gyroscope in Figure 2 with respect to a first plane; and

[0037] Figure 10 is a sectional view of a first detail of the gyroscope in Figure 2 with respect to a second plane;

[0038] Figure 11 is a sectional view of a second detail of the gyroscope in Figure 2;

[0039] Figure 12 is a sectional view of a third detail of the gyroscope in Figure 2;

[0040] Figure 13 is a sectional view of a fourth detail of the gyroscope in Figure 2;

[0041] Figure 14 is a longitudinal sectional view showing an alternative embodiment of a flywheel with a shaft;

[0042] Figure 15 is an enlarged longitudinal sectional view of a portion of a gyroscope according to an embodiment alternative to the one which is shown in Figure 5; and

[0043] Figure 16 is an enlarged view of another portion of a gyroscope according to an embodiment alternative to the one in Figure 4. Detailed description

[0044] With reference to die numbering adopted in the accompanying sheets of drawings, reference number 10 indicates, as a whole, a gyroscopic effect anti -roll stabilizer for a seacraft.

[0045] The anti-roll stabilizer 10 comprises a frame 11 and a gyroscope 1.

[0046] The gyroscope 1 comprises a dismountable container 2, for example a container having a substantially and / or essentially spherical shape, typically made of metal, for example an aluminium alloy.

[0047] The dismountable container 2 of the gyroscope 1 is mounted on a suspension 102 integral with the frame 11 and is adapted to oscillate about a first rotational axis Y (also known as the precession axis) parallel to the pitch axis of the hull of the seacraft which houses the anti -roll stabilizer 10.

[0048] A damper 103 is provided to dampen the oscillations of the container 2 of the gyroscope 1 about the first rotational axis Y.

[0049] In particular, the damper 103 can be a hydraulic damper with an adjustable damping coefficient (for example depending on the angular velocity coy of oscillation of the container 2 about the axis Y and / or other parameters such as the angular position of the container with respect to the frame 11 and the angular position of the stabiliser 10 with respect to the roll axis of the hull where the stabiliser 10 is located).

[0050] For example, the damper 103 may comprise four hydraulic pistons, two on each side.

[0051] The damper 103 may comprise one or more proportional valves (not shown) to adjust the oil flow into and out of the hydraulic pistons 103.

[0052] In the shown embodiment, the dismountable container 2 is an airtight container.

[0053] The gyroscope 1 may comprise a vacuum sensor, not shown, which is located in the container 2 so as to detect the pressure inside the container 2; furthermore, a vacuum pump (not shown) may be provided which is activated if the internal pressure of the container 2 exceeds a predetermined value.

[0054] In the shown embodiment, the dismountable container 2 comprises a first annular element 21 and a second annular element 22, which are symmetrically arranged with respect to a secant (equatorial) plane.

[0055] The first and second annular elements 21, 22 are connected to each other by means of reversible fastening elements, for example threaded elements such as screws and threaded holes.

[0056] In the shown example, the first and second annular elements 21, 22 are directly connected to each other.

[0057] In this embodiment, both annular elements 21, 22 are coupled rotoidally with the suspension 102.

[0058] In an alternative embodiment, not shown, the first and second annular elements 21, 22 can be connected to each other by means of an intermediate element which is adapted to be mounted on the suspension 102 so as to allow the container 2 to oscillate about the first axis Y.

[0059] The dismountable container 2 of the gyroscope 1 defines a chamber 20, approximately spherical, which houses a flywheel 3.

[0060] The flywheel 3 is mounted on a shaft 4 and is adapted to rotate about a second rotational axis X, orthogonal to the first axis Y. In the absence of the pitching movement, the second axis X, or rotational axis of the gyroscope flywheel, corresponds to the yaw axis of the hull of the seacraft.

[0061] The anti-roll stabilizer 10 and the gyroscope 1 are also subjected to oscillation with respect to a third axis Z, which is also orthogonal to the first axis Y, parallel to the pitch axis.

[0062] The shaft 4 of the flywheel 3 comprises a first end 41 and a second end 42, which is opposite to the first end 41.

[0063] A first bearing support member 5 is provided to support the first end 41 of the rotating shaft 4, and a second bearing support member 6 is provided to support the second end 42 of the rotating shaft 4.

[0064] The first and the second support member 5, 6 allow the shaft 4, and thereby the flywheel 3, to relatively rotate with respect to the container 2.

[0065] An electric motor 9 is provided to rotate the shaft 4 and thereby the flywheel 3.

[0066] In the shown example, the motor 9 is a radial flux motor, more precisely it is a motor with an internal rotor 91 and an external stator 92.

[0067] In the shown embodiment, the rotor 91 is connected to the first end 41 of the shaft 4 by means of a coupling 93.

[0068] Therefore, when the rotor 91 is rotated, it transmits motion to the shaft 4 and the flywheel 3.

[0069] In a possible embodiment, the electric motor 9 is positioned inside the container 2 but is located outside the space between the first and second support member 5, 6.

[0070] In the shown example, the dismountable container 2 also comprises a first cover or cap 23 (which covers the motor 9 and the first support member 5 of the shaft 4) and a second cover or cap 24, opposite to the first cover 23 (which covers the second support member 6 of the shaft 4).

[0071] In the shown example, the flywheel 3 is a circular crown flywheel and has a central hole 31 to allow a central part of the shaft 4 to be inserted.

[0072] In the exemplary embodiment, the central part of the shaft 4 has a flanged portion 40 designed to abut a seat 30, made in the flywheel 3.

[0073] In this embodiment, fastening elements are also provided to releasably connect the shaft 4 to the flywheel 3.

[0074] In particular, a plurality of screws is provided to tighten the flanged portion 40 of the shaft 4 to the seat 30 of the flywheel 3.

[0075] Again, a suitable conical flange 35 is provided on the side opposite to the seat 30 of the flywheel 3, which is coupled, by interference, to a portion 32, with reduced thickness, of the flywheel 3.

[0076] In an alternative embodiment, the flywheel 3 and the shaft 4 form a single body.

[0077] In the shown embodiment, the first support member 5 of the shaft 4 comprises: a first element, or external element 51, which is made integral with the first annular element 21 of the container 2, for example by means of reversible fastening elements; and first rolling bearings 81, 82, interposed between the external element 51 and the first end 41 of the shaft 4.

[0078] The external element, 51 and the first bearings 81, 82 are arranged coaxially to the axis X.

[0079] The first rolling bearings 81, 82 have outer rings 811, 821 which are made integral with the first element or external element 51 of the first support 5 and inner rings 812, 822 which are made integral with the first end 41 of the shaft 4.

[0080] The outer rings 811, 821 and the first element or external element 51 of the first support member 5 can be connected to each other by weak interference.

[0081] The inner rings 812, 822 and the first end 41 of the shaft 4 can be connected to each other by weak interference.

[0082] Similarly, the second support member 6 of the shaft 4 comprises: a first element, or external element 61, which is integral with the second annular element 22 of the container 2, and second rolling bearings 83, 84 which are interposed between the first element 61 and the second end 42 of the shaft 4.

[0083] The external element 61 and the second bearings 83, 84 are arranged coaxially to the axis X.

[0084] The second bearings 83, 84 have outer rings 831, 841 which are integral with the first element, or external element 61 of the second support member 6 and inner rings 832, 842 which are made integral with the second end 42 of the shaft 4.

[0085] The outer rings 831, 841 and the first element or external element 61 of the second support member 6 can be connected to each other by light interference.

[0086] The inner rings 832, 842 and the second end 42 of the shaft 4 can be connected to each other by light interference.

[0087] The bearings 81, 82 of the first support member 5 thus have outer rings 811, 821 which are made integral with the first annular element 21 of the container 2 and thereby act as stationary rings and inner rings 832, 842 which are made integral with the first end 41 of the shaft 4 and thereby act as rotating rings.

[0088] Similarly, the bearings 83, 84 of the second support member 6 have outer rings 831, 841 which are made integral with the second annular element 22 of the container 2 and thereby act as stationary rings and inner rings 832, 842 which are made integral with the second end 42 of the shaft 4 and thereby act as rotating rings.

[0089] As shown in the attached sheets of drawings, each one of the two ends 41, 42 of the shaft 4 has a shoulder to allow the bearings 81, 82 and 83, 84 to be correctly mounted.

[0090] In the shown example, the first element, or external element 51 of the first support member 5 comprises a recess 510, extending coaxially to the axis X, adapted to contain the first bearings 81, 82.

[0091] Similarly, the first element 61 of the second support member 6 comprises a recess 610, extending coaxially to the axis X, adapted to contain the second bearings 83, 84. In the shown example, a sleeve 512, for example a steel sleeve, is inserted in the internal surface of the recess 510 of the external element 51 of the first support member 5.

[0092] The outer rings 811, 821 of the first bearings 81, 82 are, therefore, coupled to the sleeve 512 which in turn is coupled to the external element 51.

[0093] This allows a sufficiently hard and resistant support surface to be created for supporting the bearings; in fact, the external element 51 is made of an aluminium alloy (to contain the overall weight of the gyroscope 1).

[0094] Similarly in the shown example, a sleeve 612, intended to be coupled to the outer rings 831, 841 of the second bearings 83, 84, is inserted in the internal surface of the recess 610 of the external element 61 of the second support member 6.

[0095] In a possible embodiment, the sleeve 612 is made of steel (while the external element 61 is made of an aluminium alloy).

[0096] In a first possible embodiment, the first bearings 81, 82 are made integral with the first end of the shaft 4 by putting the inner rings 812, 822 and 823, 824 directly on the opposite ends 41, 42 of the shaft 4.

[0097] In another possible embodiment, the first support member 5 of the shaft 4 further comprises a second element 52, or internal element, which is coaxial to the first element 51.

[0098] The second element 52 is integral with the first end 41 of the shaft 4 and the first bearings 81, 82 are interposed between the first element, or external element 51, and the second element or external element 52.

[0099] Similarly, even the second support member 6 also comprises a second element, or internal element 62, which is coaxial to the first element 61.

[0100] The second element 62 is integral with the second end 42 of the shaft 4, and the second bearings 83,84 are interposed between the first element, or external element 61, and the second element or external element 62 of the second support member 6.

[0101] In a possible embodiment, the second element 52 of the first support member 5 comprises a bush 52 on which the inner rings 812, 822 of the rolling bearings 81, 82 are mounted.

[0102] The bush 52 is in turn put on the first end 41 of the shaft 4.

[0103] In the shown embodiment, the first end 41 of the shaft 4 has a shoulder which ensures that the bush 52 and the first end 41 of the shaft 4 are correctly positioned in relation to each other.

[0104] In the shown embodiment, the external surface of the bush 52 has a shoulder which ensures that the first pair of bearings 81, 82 is correctly positioned.

[0105] In the shown example, the second element 62 of the second support member 6 comprises a bush 62 on which the inner rings 832, 842 of the rolling bearings 83, 84 are mounted.

[0106] The bush 62 is in turn mounted onto the second end 42 of the shaft 4.

[0107] In the shown embodiment, the second end 42 of the shaft 4 has a shoulder which ensures that the bush 62 and the second end 42 of the shaft 4 are correctly positioned in relation to each other.

[0108] In the shown embodiment, the external surface of the bush 62 has a shoulder which ensures that the second pair of bearings 83, 84 is correctly positioned. The bushes 52, 62 and the inner rings 812, 822; 832, 842 of the first and second bearings 81, 82; 83, 84 are made integral with the ends 41, 42 of the shaft 4, respectively, by means of locking brackets 53, 63 (for example having an annular shape), screwed to the opposite ends 41, 42 of the shaft 4, which press axially (along the axis X).

[0109] In this way, the bushes 52, 62 and the inner rings 812, 822, 832, 842 rotate together with the shaft 4.

[0110] In the shown example, the first element 51 of the first support member 5 comprises a flanged portion 511, coaxial to the axis X, which is interposed between the first annular element 21 and the first cover 23 and is fastened, by means of reversible fastening members, to the first annular element 21 of the container 2.

[0111] Similarly, the first element 61 of the second support member 6 comprises a flanged portion 611, coaxial to the axis X, which is interposed between the second annular element 22 and the second cover 24 and is fastened, by means of reversible fastening members, to the second annular element 22 of the container 2.

[0112] The flanged portion 511 of the first element 51 and the flanged portion 611 of the first element 61 help (together with the first and second annular elements 21, 22 and with the first and second covers 23, 24) to constituting the container 2 of the gyroscope 1.

[0113] This construction solution represents an undoubted advantage in terms of ease of construction and maintenance of the gyroscope.

[0114] In fact, the entire container 2 must not necessarily be removed to pull out and replace the bearings of one of the support members 5, 6, it being instead sufficient to remove, after removing the cover 23 (or the cover 24) the screws that hold the flanged part 511 (or the flanged part 611) fastened to the annular element 21 (or the annular element 22) and unscrew the crews of the locking brackets 54 (or 64) from the end 41 (or the end 42) of the shaft 4 and slide the entire support member 5 or 6 upwards.

[0115] This feature of the gyroscope is particularly advantageous.

[0116] In fact, the bearings of the gyroscopes of the anti -roll stabilizers are subject to heavy wear, as they must withstand very high axial and radial thrusts, and consequently they can be subject to frequent replacements.

[0117] In the shown example, the annular elements 21, 22, the covers 23 and 24 and the flanged portions 511, 611 are coupled together by means of gaskets (for example O-rings), so as to allow an airtight coupling.

[0118] In the shown example, a first forced liquid cooling device 87 to dissipate the heat generated by the rolling bearings 81, 82 of the first support device 5 of the shaft 4, and a second forced liquid cooling device 88, to dissipate the heat generated by the rolling bearings 83, 84 of the second support device 6 of the shaft 4 are provided.

[0119] For this purpose, the body of the external element 51 of the first support device 5 is passed through by at least one channel 871 for the passage of the cooling liquid.

[0120] The cooling liquid enters the channel 871 through an inflow opening 872 for the inflow of the cooling liquid and exits through an outflow opening 873. The openings 872, 873 are located on the external surface of the flanged portion 511 of the first element of the first support member.

[0121] Similarly, the body of the external element 61 of the second support device 6 of the shaft 4 is passed through by at least one channel 881 for the passage of the cooling liquid.

[0122] The cooling liquid enters the channel 881 through the inflow opening 882 for the inflow of the cooling liquid and exits through an outflow opening 883 (not shown).

[0123] The openings 882, 883 are located on the external surface of the flanged portion 611 of the first element of the second support member.

[0124] Therefore, the cooling liquid t supply ducts are made exclusively in the body of the external elements 51, 61 of the support members 5, 6.

[0125] To monitor the temperature of the bearings 81, 82; 83, 84, two probes (LI in Fig. 12 and Ml in Fig. 13) are provided which measure the temperature inside the first elements 51 and 61 of the support members 5, 6 near the external rings 811, 821; 831, 841 of the bearings.

[0126] The holes for inserting these probes (L2 in Fig. 12 and M2 in Fig. 13) can be made entirely in the flanged portion 511 and 611 of the support members 5, 6 and therefore without the need to provide for the presence of sealing members to maintain the vacuum conditions inside the sphere.

[0127] The solution described therefore does not require the need to drill the walls of the container to insert appropriate supply pipes for supplying the cooling liquid or to insert the temperature probes, thus avoiding the need to provide further additional gaskets or other special measures to maintain the airtightness of the container 2.

[0128] The cooling liquid can be, for example, a mixture of water and glycol.

[0129] In the example illustrated, the electric motor 9 is also cooled by a hydraulic circuit, which connects to the circuit already provided for cooling the bearings.

[0130] In the shown embodiment, the first rolling bearings 81, 82 comprise a pair of angular contact ball bearings 81, 82 arranged in tandem, that is to say with parallel load action lines, and the second bearings 83, 83 are angular contact ball bearings and are also arranged in tandem.

[0131] In the shown example, the first and second angular contact rolling bearings 81, 82; 83, 84 have the same contact angle.

[0132] More specifically, the first bearings 81, 82 are arranged in such a way that the axial thrust load is directed towards the first end 41 of the shaft 4 while the second bearings 83, 84 are arranged in such a way that the axial thrust load is directed towards the second end 42 of the shaft 4.

[0133] In the shown example, spacers 861, 862; 863, 864 are interposed between the paired rings of the bearings 81, 82 and 83, 84.

[0134] In other words, the first bearings 81, 82 and the second bearings 83, 84 are arranged in such a way that their thrust directions form an “O” configuration, that is to say with load lines diverging outwardly.

[0135] The tandem arrangement of the two pairs of bearings 81, 82; 83, 84 allows for a preload system to be provided for the bearings 81, 82 and the second bearings 83, 84. In the shown embodiment, a preload member 7 is provided (better described below) to axially preload the (stationary) outer rings 831, 841 of the angular contact ball bearings 83, 84 on the corresponding inner rings 832 and 842 of the second support 6.

[0136] The preload member 7 generates a force F having the same direction as the X axis and directed towards the end 42 of the shaft 4.

[0137] The preload action exerted by the preload member 7 is also transmitted to the bearings 81, 82 of the first support 5 through the shaft 4.

[0138] In particular, the preload action generated by the preload member 7 allows the bearings to be able to better absorb the axial and radial thrusts that are generated due to the oscillatory movement of the container 2 about the first axis Y (which oscillatory movement, due to the gyroscopic effect, is caused by the rolling of the seacraft when at sea).

[0139] In the shown embodiment, the preload member 7 is able to generate a variable load, during the operation of the gyroscope 1 depending on the operating conditions of the gyroscope 1.

[0140] In particular, the load generated by the preload member 7 can vary depending on the angular velocity coy with which the flywheel 2 oscillates about the first axis Y, due to the gyroscopic effect caused by the rolling of the seacraft on which the gyroscope is placed).

[0141] As better described below, the adjustment of the preload exerted on the bearings 81, 82, 83, 84 can also vary depending on one or more additional operating parameters such as the rotational speed of the gyroscope flywheel, the roll angle of the seacraft on which the gyroscope is placed and the angular roll velocity of the seacraft).

[0142] In the shown example, the preload member 7 comprises a piston 71 (for example a body with a generic annular shape such as a bush) which is able to slide along the axis X.

[0143] The piston 71 is therefore able to push against the outer rings 831, 841 of the angular contact ball bearings 83, 84 so as to subject the second bearings 83, 84 and, through the shaft 4, also the first bearings 81, 82 to the axial preload.

[0144] In the shown example, the piston 71 is substantially a hollow rotational solid.

[0145] As better explained below, a first force Fl, generated by at least one elastic element 72, which guarantees a minimum preload value, acts on the piston 71.

[0146] The at least one elastic element 72 allows, among other things, to guarantee a "constant" preload, even in the presence of the temperature variations that tend to thermally expand the elements involved.

[0147] In particular, the at least one elastic element 72 allows to guarantee a constant preload.

[0148] In the shown example, the first force Fl is generated by a plurality of helical springs 72, 72, ... , 72, circumferentially distributed about the axis X, which work under compression and provide the minimum desired preload value.

[0149] In the shown example, the piston 71 can be subjected, if required or deemed convenient, to a second force F2, synergic to the first force Fl, obtained by means of a hydraulic thrust. The hydraulic thrust that generates the second force F2 can be adjusted according to the working conditions of the gyroscope 1

[0150] For example, the value of the hydraulic thrust can be adjusted according to the angular velocity coy with which the flywheel 2 oscillates about the first axis Y, the angular velocity cox with which the flywheel rotates about the second axis X, the angular velocity coz with respect to the third axis Z and the inclination of the gyroscope 1 with respect to the third axis Z.

[0151] In this way, it is possible to adjust the preload applied to the bearings 81, 82; 83, 84 according to certain operating conditions and, in general, the radial and axial loads that they must withstand during the operation of the gyroscope 1 and thereby of the anti -roll stabilizer 10.

[0152] In other words, thanks to this feature, the axial preload generated by the preload member 7 can be adapted to the stresses to which the bearings 81, 82; 83, 84 are subjected, which stresses in turn depend on the sea conditions.

[0153] It is therefore possible to work with a low axial preload, so as to reduce the friction to which the bearings are subjected, for example during the start-up phase of the gyroscope (a phase that can last even more than one hour) or when the sea is calm, thus increasing the operating life of the rolling bearings 81, 82; 83, 84.

[0154] It is also possible to work with a high axial preload, to allow the bearings to resist the radial and axial thrusts generated by the mass of the flywheel during the oscillation of the container 2, which oscillation is caused by the rolling of the seacraft, which radial and axial thrusts are more or less large depending on the sea conditions.

[0155] In this way, the operating life of the bearings is increased, preventing them from always being subjected to a maximum preload condition.

[0156] In fact, it is not necessary to apply the full preload in every operating condition, because the preload can be kept lower, if allowed by the sea conditions

[0157] A high preload in fact means greater resistance to the axial and radial load but also greater mechanical wear and a shorter life of the bearings.

[0158] In other words, in the gyroscope described the preload of the bearings is adjustable, depending on the operating conditions of the gyroscope and, in particular, depending on the oscillation speed of the gyroscope about the first axis Y (that is to say the precession speed of the gyroscope flywheel following the roll to which the hull where the anti-roll stabilizer is housed is subjected).

[0159] In the shown example, the piston 71 is a single-acting piston that can be adjusted by introducing a pressurized fluid, for example a hydraulic oil, into a chamber 73 delimited by a portion of the surface of the first element 61 of the second support member 6 and a portion of the surface of the piston 71.

[0160] The chamber 73 is fed with a pressurized oil through a duct 771.

[0161] The duct 771 receives the oil through an opening 77.

[0162] In the shown example, the opening 77 is made on the flanged portion 661 of the first element, 61 of the second support member 6. This solution therefore does not require the need to drill the walls of the container to insert appropriate supply pipes for supplying the pressurized oil, thus avoiding the need to provide further additional gaskets or other special measures to maintain the airtightness of the container 2.

[0163] The opening 77 is hydraulically connected through an external pipe 75 with a hydraulic actuator 74 which is able to introduce a pressurized fluid, for example a hydraulic oil, into the chamber 73.

[0164] The hydraulic actuator 74 can be, for example, an external hydraulic piston pump, driven by a gearmotor unit 76, (the electric motor 761 and the planetary gearbox 762), which is in turn controlled by a regulator 78, for example an electronic regulator.

[0165] The hydraulic oil pressure is detected by a special sensor 79 which is positioned downstream of the hydraulic pump.

[0166] The hydraulic actuator 74 is able to adjust the intensity of the piston thrust on the rings of the outer rings 832, 842 of the angular contact ball bearings 83, 84 of the second support 6, thereby varying the axial preload of all the bearings of the gyroscope 1.

[0167] In the shown example, the electronic regulator 78 is interfaced to a first sensor 781 from which a first signal arrives which represents the angular position of the container 2 and the angular velocity coy with which the container 2 oscillates about the first axis Y (precession motion), a second sensor 782 from which the quantity cox is obtained, representing the angular velocity of the flywheel 2 around the second axis X (constant speed at steady state) and a third sensor 783, for example a Mems integrated inside the regulator, which provides the angle and its derivative with respect to the third axis Z).

[0168] In the shown embodiment, the regulator 78 therefore provides an output signal, to control the motor 761, according to the information indicated above and the operating state of the gyroscope (acceleration phase or constant speed operation phase).

[0169] The hydraulic actuator 74 can be kept deactivated until the angular velocity cox of the flywheel 3 reaches the steady state and the angular velocity coy of oscillation of the container 2 does not exceed a preset value.

[0170] In fact, it has been verified that this method of managing the preload of the rolling bearings allows to significantly extend their operating life.

[0171] In further embodiments, not shown, the hydraulic actuator 74 can generate a fair amount of pressure values, or continuously vary the pressure, depending on the operating conditions of the gyroscope 1.

[0172] In a further embodiment, the regulator 78 can comprise a feedback control to reduce the pressure variations due to the temperature variations in the pressurized liquid pumped into the chamber 73. Schedule of Reference Numerals

[0173]

Claims

CLAIMS1. A gyroscope for an anti -roll stabilizer for a seacraft (10), comprising a) a dismountable container (2), which defines a chamber (20), al) adapted to be mounted on a suspension (102) so as to able to oscillate about a first axis (Y); a2) comprising a first cover (23), a first annular element (21), a second annular element (22), and a second cover (24) distributed along a second axis (X) orthogonal to said first axis (Y), said first cover (23), said first annular element (21), said second annular element (22) and said second cover (24) being connected to each other by means of reversible fastening elements; b) a flywheel (3), placed inside said chamber (20) of said dismountable container (2), bl) said flywheel (3) being mounted on a shaft (4) and being adapted to rotate about a second axis (X), orthogonal to said first axis (Y), b2) said shaft (4) of said flywheel (3) having a first end (41) and a second end (42) which is opposite to said first end (41); c) a first support member (5) placed inside said dismountable container (2), to support said first end (41) of said shaft (4), cl) said first support member (5) comprising a first element (51), which is made integral with said first annular element (21) of the container (2) by means of reversible fastening means, and first rolling bearings (81, 82), interposed between said first element (51) and said first end (41) of said shaft (4); c2) said first rolling bearings (81, 82) having outer rings (811, 821) integral with said first element (51) of said first support member (5) and inner rings (812, 822) integral with said first end of said shaft (4); d) a second support member (6), placed inside said dismountable container (2), to support said second end (42) of said shaft (4), dl) said second support member (6) comprising a first element (61), integral with said second annular element (22) of the container (2), and second rolling bearings (83, 84) interposed between said first element (61) and said second end (412) of said shaft (4); d2) said second rolling bearings (83, 84) having outer rings (831, 841) integral with said first element (61) of said second support member (6) and inner rings (832, 842) integral with said second end (42) of said shaft (4); e) an electric motor (9), which is adapted to transmit a torque to said flywheel (3); characterized in thatsaid first element (51) of said first support member (5), comprises a flanged portion (511), which is interposed between said first annular element (21) and said first cover (23) and is fastened, by means of reversible fastening members, to the first annular element (21) of the container (2) and to said first cover (23) and in that said first element (61) of said second support member (6), comprises a flanged portion (611), which is interposed between said second annular element (22) and said second cover (24) and is fastened, by means of reversible fastening members, to the second annular element (22) of the container (2) and to said second cover (24).

2. The gyroscope (1), according to claim 1, wherein said first element (51) of said first support member (5) is passed through by at least one channel (87) for the passage of a cooling liquid and wherein said flanged portion (511) of said first element (51) of said first support member (5) comprises an inflow opening (872) and an outflow opening (873) of said cooling channel (87), and wherein said first element (61) of said second support member (5) is passed through by at least one channel (88) for the passage of a cooling liquid and wherein said flanged portion (611) of said first element (61) of said second support member (6) comprises an inflow opening (882) and an outflow opening (883) of said cooling channel (88).

3. The gyroscope (1), according to claim 2, wherein said flanged portions (511, 611) further comprise a blind hole in which a temperature probes is inserted.

4. The gyroscope, according to one of the preceding claims, comprising a preload member (7) to axially preload the outer rings (831, 841) of said second bearings (83, 84), said preload member (7) comprising a piston (71), able to slide along the axis (X), actuated by means of a hydraulic thrust, wherein the oil to adjust said piston (71) is introduced through a duct (771) having an opening (77) made on the flanged portion (611) of the first element (61) of the second support member (6).

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