Rotating structure for large-scale civilian applications, such as a telescope in an astronomical observatory, equipped with self-centering hydrostatic gliders

Abstract

Rotating structure (4) for civil applications, which has the following features: - a stationary section (8) and a movable section (12) which is rotatable about an axis of rotation (XX) and is equipped with means for its rotation about the axis of rotation (XX), - wherein the fixed section (8) and the movable section (12) are at least partially opposite in shape at a sliding surface (16) of the movable section (12), wherein the sliding surface (16) has a cylindrical, conical or toric shape with respect to the axis of rotation (XX), - wherein at least one self-centering hydrostatic slider (20) is arranged on the sliding surface (16), - wherein the at least one self-centering hydrostatic slider (20) comprises a fixed base (24) and a hydrostatic support (28) arranged between the base (24) and the sliding surface (16), - wherein the hydrostatic support (28) of the base (24) is associated via a double-acting piston (32) which has two opposing chambers (36, 40), - wherein the hydrostatic support (28) comprises a plate (48) facing directly towards the sliding surface (16), the plate (48) defining four pockets (52, 54, 56, 58) filled with pressurized oil and facing directly towards the sliding surface (16), from which they are separated by an intermediate space (60) filled with pressurized oil having a nominal height, the four pockets (52, 54, 56, 58) being in fluid communication in pairs opposite each other with the chambers (36, 40) of the double-acting piston (32) to cause the axial displacement of the double-acting piston (32) along an actuating axis (SS) when the nominal height of the intermediate space (60) and the oil pressure in the pockets (52, 54, 56, 58) change, thereby causing a rotation of the plate (48) of the hydrostatic support (28) is generated with respect to the sliding surface (16) to create the spaces (60) of the pockets (52, 54, 56,58) to bring to the nominal height and to equalize the pressure in the pockets (52, 54, 56, 58).

Description

SCOPE

[0001] The present invention relates to a rotating structure for large-scale civil applications, such as a telescope of an astronomical observatory, which is equipped with self-centering hydrostatic gliders. STATE OF THE ART

[0002] In particular, but not exclusively, the present invention is applicable to rotating structures with extremely high mass, even on the order of tens of thousands of tons, such as large telescopes, but generally to civil structures equipped with rotary movements about an axis.

[0003] In engineering, the production of rotary structures is known, which rotate on very thick round supports to support the rotational movement of the rotary structure and to limit deformations as much as possible.

[0004] These structures are set in rotation by means of drives that must enable extremely precise and controlled movements.

[0005] In particular, the control of the rotation of the rotating structure, for example the support structure of the telescope mirrors, must be precise, otherwise the alignments carried out with the telescope will not be reliable.

[0006] Given the high masses involved, the moving structures are naturally supported by hydrostatic gliders, which must prevent any contact between the mechanical sections moving relative to each other.

[0007] In fact, these hydrostatic gliders ensure the presence of a very thin film of oil between the sections that move relative to each other.

[0008] As is known, the amount of oil used by a hydrostatic glider to fulfill its hydrostatic support function varies with the cubic distance between the surfaces to be supported.

[0009] This means that the delivery rate increases approximately 1000-fold when the distance between the sections increases from 1 / 10 mm to 1 mm.

[0010] In small structures, this problem is circumvented, for example, by extremely precise assembly, and even if alignment errors have to be compensated for, the increase in flow rate remains acceptable and manageable due to the small overall dimensions.

[0011] The situation is quite different with large-scale structures, such as telescopes.

[0012] On the one hand, it is impossible to carry out precision pre-assembly, as the structures have a diameter of up to 40 m and necessarily have to be assembled on site, since such telescopes are placed in inaccessible locations and often at altitudes of several thousand meters.

[0013] Since no pre-assembly can be carried out and, given the absolute size of the structure, precise on-site assembly cannot be guaranteed, the solution with hydrostatic sliders would require very high fluid flow rates to compensate for the inevitable misalignments that would occur between the sections.

[0014] The problem becomes even more complicated when the structure is used in environments exposed to seismic phenomena, including those of considerable strength, as is often the case with large telescopes located in inaccessible and often mountainous places.

[0015] Furthermore, the problem becomes even more complicated with large structures that are subject to deformations due to their own weight during rotation, or with strong temperature fluctuations and shrinkage of the concrete from which the foundation and / or other sections of the rotating structure are made: As we have seen, these phenomena have a particularly large impact on large telescopes that are erected in inaccessible and often mountainous locations.

[0016] Therefore, the known solutions with hydrostatic gliders are not recommended for specific applications on large structures such as telescopes, as they would be difficult to develop and would cause disproportionately high operating and maintenance costs. PRESENTATION OF THE INVENTION

[0017] Therefore, it is necessary to overcome the aforementioned disadvantages and limitations of the known technology.

[0018] This need is met by a rotary structure for civil applications, equipped with self-centering hydrostatic sliders according to claim 1. DESCRIPTION OF THE FIGURES

[0019] Further features and advantages of the present invention will be better understood from the following description of its preferred and non-limiting embodiments, wherein: Fig. 1 shows a side view of a rotary structure for civil applications according to a possible embodiment of the present invention; Fig. 2 a side view of the enlarged detail II from Fig. 1 represents; Fig. 3-6 different side views, some in section, of components of the rotating structure for civilian applications Fig. 1 represent; Fig. Figure 7 shows a schematic side view of a self-centering hydrostatic glider according to an embodiment of the present invention; Fig. Figure 8 shows a schematic top view of a self-centering hydrostatic glider according to an embodiment of the present invention; Fig. 9 a sectional view of the self-centering hydrostatic glider made of Fig. 8 shows.

[0020] The elements or parts of elements that are common to the embodiments described below are identified by the same reference numerals. DETAILED DESCRIPTION

[0021] With reference to the figures mentioned above, figure 4 represents a rotating structure for civil applications according to the present invention.

[0022] First, for the purposes of the present invention, it is necessary to clarify that the term "rotational structure" is to be understood in a broad sense and refers to any structure that exhibits a relative rotational movement with respect to a base; this movement can be rotary and / or rototranslatory. In this case, the rotational movement can, for example, as described in more detail below, occur about a vertical axis, i.e., perpendicular to an overall support surface for the structure.

[0023] Furthermore, a rotational structure is also understood to be a structure that exhibits a relative rotational movement with respect to a partially enclosing shell. In this case, the rotational movement can, as described in more detail below, occur, for example, around a horizontal axis, i.e., parallel to the overall bearing surface of the structure.

[0024] Preferably, but not exclusively, this rotating structure 4 for civilian applications can include a dome for covering and / or mounting a telescope, but also a residential structure.

[0025] The rotary structure 4 for civil applications comprises a fixed section 8 and a movable section 12 which rotates about a rotary axis XX and is equipped with drive means for its rotation about the rotary axis XX.

[0026] The axis of rotation XX can be defined by one or more bearings or similar supports. The axis of rotation XX can be, for example, horizontal or vertical. A single rotating structure 4, such as a telescope, can comprise several fixed sections 8 and several movable sections 12 that rotate about different axes of rotation XX, which can, for example, be perpendicular to each other.

[0027] For example, in the case of a telescope, a first axis of rotation XX can be a vertical axis or an azimuth axis, while a second axis of rotation XX can be a horizontal axis or an altitude axis.

[0028] In other words, the same structure can comprise several fixed sections 8 and several movable sections 12 that rotate about different axes of rotation XX.

[0029] For example, the fixed section 8 and the movable section 12 are coaxial to the axis of rotation XX.

[0030] The drive means can be of various types; preferably they are electric motors with torque and / or current feedback control for moving the movable section 12 about the respective axis of rotation XX.

[0031] The fixed section 8 and the movable section 12 are at least partially offset from each other on a sliding surface 16 of the movable section 12, which has a cylindrical, conical or toric shape with respect to the axis of rotation XX.

[0032] Advantageously, at least one self-centering hydrostatic slider 20 is arranged on the sliding surface 16.

[0033] In particular, the at least one self-centering hydrostatic slider 20 comprises a fixed base 24 and a hydrostatic support 28 arranged between the base 24 and the movable section 12.

[0034] Furthermore, the hydrostatic support 28 is associated with the base 24 via a double-acting piston 32, which has two opposing chambers, for example a first chamber 36 and a second chamber 40, which are delimited by a cylinder 42 filled with pressurized oil. The first chamber 36 and the second chamber 40 are separated from each other by a partition 44, which prevents a hydrostatic connection between the chambers 36 and 40. The partition 44 can, for example, be provided with one or more seals.

[0035] The hydrostatic support 28 includes a plate 48 which is directly adjacent to the movable section 12.

[0036] In particular, the plate 48 defines four pockets 52, 54, 56, 58 (i.e., a first pocket 52, a second pocket 54, a third pocket 56, and a fourth pocket 58) filled with pressurized oil and directly facing the sliding surface 16, from which they are separated by a pressurized oil-filled space 60 of a nominal height. It should be specified that the nominal height of the space 60 must be measured along a radial direction RR that is perpendicular to and intersects the axis of rotation XX.

[0037] The four pockets 52, 54, 56, 58 are fluidically connected in pairs opposite each other to the chambers 36, 40 of the double-acting piston 32 in order to achieve an axial displacement of the double-acting piston 32 along an actuation axis SS when the nominal height of the gap 60 and the oil pressure in the pockets 52, 54, 56, 58 change, thereby generating a rotation of the plate 48 of the hydrostatic support 28 relative to the sliding surface 16 in order to bring the gaps 60 of the pockets 52, 54, 56, 58 to the nominal height and to equalize the pressure in the pockets 52, 54, 56, 58.

[0038] In other words, the oil pressure in the pockets 52, 54, 56, 58 depends on the height of each gap 60, i.e., on the distance of each pocket 52, 54, 56, 58 from the sliding surface 16. If these gaps 60 are equal, even if the movable section 12 and the fixed section 8 are not correctly aligned and coaxial with respect to the axis of rotation XX, the presence of the self-centering slider can still make the surfaces of the sliding surface 16 and the slider 48 parallel: In this way, the oil pressure is the same in the pockets 52, 54, 56, 58 as well as in the first chamber 36 and the second chamber 40 of the double-acting piston 32. Thanks to the equal pressure in chambers 36, 40, the double-acting piston is in equilibrium, does not move, and thus the correct alignment of the sliding surface 16 with respect to the plate 48 of the self-centering hydrostatic slider 20 is maintained.

[0039] However, should a misalignment occur between the sliding surface 16 and the plate 48 of the self-centering hydrostatic slider 20, a change in the gaps 60 between the sliding surface 16 and the pockets 52, 54, 56, 58 would result, leading to a corresponding change in oil pressure. This change in oil pressure would, as seen, be transmitted to the chambers 36, 40 of the double-acting piston 32, which would shift so that the movable section 12 would be correctly aligned with the fixed section 8 again.

[0040] According to one embodiment, the four pockets 52, 54, 56, 58 are arranged identically and symmetrically about a central axis CC, which is perpendicular to and intersects the axis of rotation XX, so that they are arranged in the form of a square. In particular, two pockets located at opposite ends of a diagonal of the square are fluidically connected to each other and to one of the opposite chambers 36, 40.

[0041] For example, the first pocket 52 and the fourth pocket 58 are fluidically connected to each other and to the second chamber 40 of the double-acting piston 32, while the second pocket 54 and the third pocket 56 are fluidically connected to each other and to the first chamber 36 of the double-acting piston 32.

[0042] Thanks to this hydrostatic cross-connection (i.e., along the diagonal of pockets 52, 54, 56, 58), an effective realignment effect can be achieved: In fact, a misalignment between the plate 48 of the self-centering hydrostatic glider 20 and the sliding surface 16 leads to an essentially identical change in the gap 60 at the pockets that are arranged diagonally, i.e., opposite the aforementioned central axis CC. Furthermore, due to the aforementioned misalignment between the plate 48 of the self-centering hydrostatic glider 20 and the sliding surface 16, an opposite change occurs between the gaps 60 of the pockets arranged on the two diagonals.In other words, the channels 60 of the second pocket 54 and the third pocket 56 are enlarged by an essentially identical amount, while at the same time the spaces 60 of the first pocket 52 and the fourth pocket 58 are reduced by an identical amount (which is opposite to the enlargement of the channels of the second pocket 54 and the third pocket 56). This arrangement therefore enables rapid self-centering or alignment of the plate 48 of the self-centering hydrostatic slider 20 with respect to the sliding surface 16.

[0043] According to one embodiment, the double-acting piston 32 terminates with a head 64 which is connected to a seat 68 of the base 24.

[0044] According to one embodiment, the seat 68 is bounded by a pair of inclined, mutually parallel planes 72, 76 which intersect the actuating axis SS in order to allow a transverse movement of the head 64 of the double-acting piston 32 along a transverse direction TT perpendicular to the actuating axis SS, corresponding to a displacement of the double-acting piston 32 along the actuating axis SS.

[0045] According to one embodiment, the double-acting piston 32 is offset from the said central axis CC by an eccentricity 80, which is perpendicular to and intersects the said actuating axis SS, so that the plate 48 rotates about the central axis CC after a displacement of the double-acting piston 32.

[0046] Preferably, the plate 48 of the hydrostatic support 28 is concave and opposite in shape to the sliding surface 16 of the movable section 12.

[0047] According to one embodiment, the fixed section 8 comprises a guide 84 which receives and supports a foot 88 of the hydrostatic support 28.

[0048] Preferably, an axial clearance 90 parallel to the axis of rotation XX and a radial clearance 94 with respect to the central axis CC are provided between the guide 84 and the foot 88 of the hydrostatic support 28, the latter being perpendicular to and intersecting the axis of rotation XX, and these clearances enable the hydrostatic support 28 to perform rotations about three axes: one parallel to the axis of rotation XX, one coinciding with the central axis CC, and one about the third axis orthogonal to the two previous ones.

[0049] Preferably, the guide 84 is a hydrostatic guide filled with pressurized fluid.

[0050] Preferably the guide 84 is provided with a seal 96 which seals against the base 88 of the hydrostatic support 28.

[0051] For example, the fixed base 24 of the at least one self-centering hydrostatic slider 20 is attached to the aforementioned guide 84.

[0052] As can be seen from the description, the structures according to the invention make it possible to overcome the disadvantages that occur in the known technology.

[0053] Advantageously, the described solution implements a rotary structure and, in particular, a zenith rotary system with self-centering, double-acting or double-functioning hydrostatic sliders.

[0054] The rotation system, for example the zenith rotation system, of the present invention exhibits a high axial stiffness of the sliders under operating conditions and a low axial stiffness of the sliders under seismic conditions, so that it can effectively withstand any seismic phenomena to which the structure might be exposed.

[0055] The rotation system, for example the zenith rotation system, of the present invention distributes the load evenly onto the various skids of each support, in particular each height support.

[0056] The rotation system, for example the zenith rotation system, of the present invention distributes the radial load evenly on the different skids of each height support.

[0057] The rotation system, for example the zenith rotation system, of the present invention has a mechanical compensation for load distribution.

[0058] In particular, the rotary system, for example the zenith rotary system, of the present invention has mechanical load distribution compensation devices that function both under operating conditions and under failure conditions of the hydraulic system.

[0059] The rotation system, for example the zenith rotation system, of the present invention is also designed for connection to temporary structures that can provide rigid and vertical support for the telescope and some flexibility in the horizontal plane, perpendicular to the vertical direction.

[0060] The rotation system, for example the zenith rotation system, of the present invention is designed in such a way as to avoid local load concentrations that could impair the functionality of the telescope.

[0061] The rotation system, for example the zenith rotation system, of the present invention is equipped with a hydrostatic compensation of a maximum of 3 hydrostatic sliders, each with a capacity of 75 tons.

[0062] The rotation system, for example the zenith rotation system, of the present invention makes it possible to mount the main structure in a stress-neutral state, without residual stresses caused by the assembly, which must be avoided because they can change the behavior of the structure during the azimuthal and zenithal rotations of the telescope mirrors in an unpredictable way.

[0063] The rotation system, for example the zenith rotation system, of the present invention makes it possible to avoid the introduction of stresses into the structure in the theoretical rest configuration by using temporary structures and by investigating special assembly techniques, and also allows the use of preloading of the screw connections before tightening, if this is necessary to achieve the load condition intended for a certain, not completely neutral geometry.

[0064] The rotation system, for example the zenith rotation system, of the present invention is applicable to next-generation telescopes with primary mirror diameters of nearly 40 m.

[0065] The rotation system, for example the zenith rotation system, of the present invention is designed to limit the thickness of the oil film of the hydrostatic sliding pieces in order to ensure high stiffness of the sliding piece and to limit the overall performance of the hydraulic system.

[0066] The rotation system, for example the zenith system, of the present invention is designed in such a way as to avoid mechanical grinding of the sliders on the cylindrical raceways.

[0067] The rotation system, for example the zenith system, of the present invention is designed to ensure the accuracy and smoothness of movement required for tracking celestial bodies with the mirrors of the telescope.

[0068] The rotation system, for example the zenith system, of the present invention is equipped with a passive device for aligning the radial sliders, which support and enable the rotation of the height structure.

[0069] The rotation system, for example the zenith system, of the present invention enables, by means of a double-acting cylinder which is hydrostatically connected to the pockets of the slider, the automatic realignment of the slider in the event of pressure changes of the oil film on the cylindrical sliding surface between the sections.

[0070] To meet specific requirements, a specialist can make numerous changes and variations to the solutions described above.

[0071] The scope of protection of the invention is defined by the following claims. Reference sign 4 Rotating structure for civilian applications 8 fixed section 12 movable section 16 Sliding surface 20 self-centering hydrostatic gliders 24 base 28 hydrostatic supports 32 double-acting pistons 36 first chamber 40 second chamber 42 cylinders 44 Partition wall 48 plate 52 first bag 54 second bag 56 third bag 58 fourth bag 60 space 64 heads 68 seats 72 inclined plane 76 inclined plane 80 eccentricity 84 Leadership 88 feet 90° axial play 94 radial play 96 Seal XX axis of rotation SS actuation axis CC central axis TT transverse direction RR Radial direction

Claims

[1] Rotating structure (4) for civilian applications, which has the following features: - a stationary section (8) and a movable section (12) which is rotatable about an axis of rotation (XX) and is equipped with means for its rotation about the axis of rotation (XX), - wherein the fixed section (8) and the movable section (12) are at least partially opposite in shape at a sliding surface (16) of the movable section (12), wherein the sliding surface (16) has a cylindrical, conical or toric shape with respect to the axis of rotation (XX), - wherein at least one self-centering hydrostatic slider (20) is arranged on the sliding surface (16), - wherein the at least one self-centering hydrostatic slider (20) comprises a fixed base (24) and a hydrostatic support (28) arranged between the base (24) and the sliding surface (16), - wherein the hydrostatic support (28) of the base (24) is associated via a double-acting piston (32) which has two opposing chambers (36, 40), - wherein the hydrostatic support (28) comprises a plate (48) facing directly towards the sliding surface (16), the plate (48) defining four pockets (52, 54, 56, 58) filled with pressurized oil and facing directly towards the sliding surface (16), from which they are separated by an intermediate space (60) filled with pressurized oil having a nominal height, the four pockets (52, 54, 56, 58) being in fluid communication in pairs opposite each other with the chambers (36, 40) of the double-acting piston (32) to cause the axial displacement of the double-acting piston (32) along an actuating axis (SS) when the nominal height of the intermediate space (60) and the oil pressure in the pockets (52, 54, 56, 58) change, thereby causing a rotation of the plate (48) of the hydrostatic support (28) is generated with respect to the sliding surface (16) to create the spaces (60) of the pockets (52, 54, 56,58) to bring to the nominal height and to equalize the pressure in the pockets (52, 54, 56, 58). [2] Rotating structure (4) for civil applications according to claim 1, wherein the four pockets (52, 54, 56, 58) are identical and arranged symmetrically to a central axis (CC) which is perpendicular to and intersects the axis of rotation (XX) such that they are arranged in the form of a square, and wherein two opposing pockets (52, 58; 54, 56) arranged along a diagonal of the square are fluidically connected to each other and to one of the opposing chambers (36, 40). [3] Rotating structure (4) for civil applications according to claim 1 or 2, wherein the double-acting piston (32) terminates with a head (64) connected to a seat (68) of the base (24), the seat (68) being bounded by inclined planes (72, 76) which are parallel to each other and intersect the actuating axis (SS), such that a rotation of the plate (48) about the central axis (CC) is achieved as a result of a displacement of the head (64) of the double-acting piston (32) along the actuating axis (SS). [4] Rotating structure (4) for civil applications according to claim 1, 2 or 3, wherein the double-acting piston (32) is offset from the central axis (CC) by an eccentricity (80) which is perpendicular to and intersects the actuating axis (SS) such that the plate (48) rotates about the central axis (CC) when the double-acting piston (32) moves. [5] Rotating structure (4) for civil applications according to any one of claims 1 to 4, wherein the fixed section (8) and the movable section (12) are coaxial with respect to the axis of rotation (XX). [6] Rotating structure (4) for civil applications according to any one of claims 1 to 5, wherein the plate (48) of the hydrostatic support (28) is concave and opposite to the sliding surface (16) of the movable section (12). [7] Rotating structure (4) for civil applications according to any one of claims 1 to 6, wherein the fixed section (8) comprises a guide (84) which receives and supports a foot (88) of the hydrostatic support (28). [8] Rotary structure (4) for civil applications according to claim 7, wherein an axial clearance (90) is provided between the guide (84) and the foot (88) of the hydrostatic support (28), parallel to the axis of rotation (XX), and a radial clearance (94) is provided with respect to a central axis (CC) that is perpendicular to and intersects the axis of rotation (XX). [9] Rotating structure (4) for civil applications according to claim 7 or 8, wherein the guide (84) is a hydrostatic guide filled with pressurized fluid. [10] Rotating structure (4) for civil applications according to claim 7, 8 or 9, wherein the guide (84) is provided with a seal (96) which seals against the base (88) of the hydrostatic support (28). [11] Rotating structure (4) for civil applications according to any one of claims 7 to 10, wherein the fixed base (24) of the at least one self-centering hydrostatic slider (20) is attached to the guide (84). [12] Rotating structure (4) for civil applications according to any one of claims 1 to 11, wherein the rotating structure (4) is a telescope and wherein the axis of rotation (XX) is a horizontal axis or a vertical axis. [13] Rotating structure (4) for civil applications according to any one of claims 1 to 11, wherein the rotating structure (4) is a telescope and the axis of rotation (XX) is a vertical axis or an azimuth axis.

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