A flexible side support structure for a mirror

Abstract

The application discloses a mirror flexible side support structure, which comprises a counterweight, a lever, a support, a flexible joint inner pressure ring, a flexible joint, a flexible joint outer pressure ring, a diaphragm outer pressure ring, a diaphragm inner pressure ring, a diaphragm, an invar block and a primary mirror. One end of the lever is connected with the counterweight, the other end of the lever is connected with a diaphragm seat through the diaphragm, the diaphragm seat is connected with the invar block, and the invar block is cemented on the primary mirror. The flexible joint serves as a lever fulcrum. The flexible joint comprises a flexible sheet one, a flexible sheet two, an inner ring, an inner pressure ring one, an inner pressure ring two, an outer ring, an outer pressure ring one and an outer pressure ring two. The flexible joint is used to replace a self-aligning ball bearing, and the diaphragm is used to replace a ball head structure and a sliding rod, so that the mirror has the characteristics of no friction and no gap, can stably provide a side support force and reduce the influence of temperature change on a mirror surface shape. Meanwhile, the mirror can reduce impact generated in the process of movement of the primary mirror from a horizontal working condition to a vertical working condition, ensure the surface shape precision of the primary mirror and be suitable for a telescope under complex working conditions with large temperature difference.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of precision instrument technology, and in particular to a flexible side support structure for a mirror. BACKGROUND

[0002] With the development of astronomy, higher requirements are put forward for telescopes, and the large aperture of the main mirror of the telescope has become one of the development trends. The main mirror, as the core component of the telescope, determines the light collecting ability and spatial resolution of the entire optical system, and directly affects the imaging quality of the telescope. However, as the aperture of the telescope increases, its mass also increases, and the mirror deformation also increases accordingly. Under complex working conditions, the temperature changes greatly, and the thermal deformation and thermal stress will affect the mirror surface shape of the telescope. In order to enable the telescope to work normally in complex and harsh environments, and to reduce the influence of external load on the mirror surface shape, the design and optimization of the support structure of the main mirror become one of the key technologies.

[0003] The general support of the main mirror of the telescope includes bottom support and side support. When the mirror barrel points to the zenith position, the bottom support bears the weight of the main mirror. When the mirror barrel points to the horizontal, the side support bears the weight of the main mirror. When the mirror barrel is between the two working states, the bottom support and the side support jointly bear the weight of the main mirror.

[0004] The side support is one of the key technologies for supporting the main mirror of a large telescope, and its performance directly affects the imaging quality of the telescope and even the safety of the main mirror. The commonly used side support methods include lever counterweight support, hydraulic / pneumatic support, mercury / steel belt support, and tangential rod support. The lever counterweight support adjusts the weight of the counterweight through the action of the lever to balance the weight of the main mirror, without the need for other automatic control system balance, reducing the complexity of the system, and can automatically adapt to the support requirements at different height angles.

[0005] However, in the existing lever counterweight support, there may be problems such as friction and clearance. Due to the existence of clearance, impact will be generated during the movement of the main mirror from horizontal to vertical working condition. Due to the existence of friction, the accuracy of the mirror support force will be reduced, thereby affecting the accuracy of the mirror surface shape. The traditional self-aligning ball bearing has sliding friction due to the rolling of the outer ring and the sliding of the inner ring. There is also sliding friction between the ball head structure and the slide rod. The use of flexible structure instead of self-aligning ball bearing, ball head structure and slide rod can realize small movement through the deformation of itself to reduce the influence of load and temperature change on the mirror surface shape, and has the advantages of no friction, no clearance and high stability, and is more suitable for mirror side support technology requiring high precision. SUMMARY

[0006] The purpose of the present application is to provide a flexible side support structure for a mirror, which has the characteristics of no friction, no clearance, simple structure and high stability. It can meet the working requirements of the main mirror under complex working conditions with large temperature difference.

[0007] In order to solve the technical problems of the present application, the technical solution is proposed: the mirror flexible side support structure is composed of a counterweight (1), a lever (2), a support (3), a flexible joint inner pressure ring (4), a flexible joint (5), a flexible joint outer pressure ring (6), a diaphragm seat (7), a diaphragm outer pressure ring (8), a diaphragm inner pressure ring (9), a diaphragm (10), an invar block (11), and a main mirror (12).

[0008] One end of the lever (2) is connected with the counterweight (1), and the other end of the lever (2) is connected with the diaphragm seat (7) through the diaphragm (10), the diaphragm seat (7) is connected with the invar block (11), and the invar block (11) is glued on the main mirror (12); the flexible joint (5) serves as the fulcrum of the lever (2).

[0009] The inner ring of the diaphragm (10) is fixed through the diaphragm inner pressure ring (9) and the lever (2), and the outer ring of the diaphragm (10) is fixed through the diaphragm seat (7) and the diaphragm outer pressure ring (8); the inner ring (503) of the flexible joint (5) is fixed through the lever (2) and the flexible joint inner pressure ring (4), and the outer ring (506) of the flexible joint (5) is fixed through the support (3) and the flexible joint outer pressure ring (6).

[0010] The flexible joint (5) includes a flexible sheet one (501), a flexible sheet two (502), an inner ring (503), an inner pressure ring one (504), an inner pressure ring two (505), an outer ring (506), an outer pressure ring one (507), and an outer pressure ring two (508).

[0011] The flexible sheet one (501) and the flexible sheet two (502) are the same in structure and size, are arranged in a cross form through four flexible sheets connected by a flexible sheet inner ring, and are obtained by twice bending of a flexible sheet three (13) at an angle θ relative to an xy plane.

[0012] Preferably, the flexible joint inner pressure ring (4) is in the shape of a circular ring, has a threaded hole at the center, and is threadedly connected with the lever (2); the flexible joint outer pressure ring (6) is in the shape of a stepped circular ring, can ensure that the contact surface is pressed tightly, has circular holes uniformly distributed on the circular ring, and is connected with the support (3) through the circular holes and the threaded holes.

[0013] The diaphragm inner pressure ring (9) is in the shape of a stepped circular ring; the diaphragm outer pressure ring (8) is in the shape of a circular ring and has circular holes uniformly distributed on the circular ring; the diaphragm (10) is in the shape of a circular ring and has circular holes uniformly distributed on the outer ring; the diaphragm seat (7) has two groups of annular threaded holes uniformly distributed thereon and has circular holes distributed on the bottom portion, and a screw is connected through the circular holes of the diaphragm outer pressure ring (8), the circular holes of the diaphragm (10), and one group of the threaded holes of the diaphragm seat (7); the screw is connected with the diaphragm cover through the other group of the threaded holes of the diaphragm seat (7).

[0014] Preferably, the main mirror (12) is glued with the invar block (11) which has a similar thermal expansion coefficient, so as to reduce the thermal stress of the main mirror (12).

[0015] Preferably, the membrane (10) used in the flexible side support structure of the mirror can eliminate friction and gap, and reduce the axial displacement of the main mirror (12) caused by the stress of the bottom support.

[0016] Preferably, the flexible joint (5) used in the flexible side support structure of the mirror can eliminate friction and gap, and improve the accuracy of the support force. The flexible joint (5) has axial and radial rigidity, and only has two rotation degrees of freedom around the x-axis and the y-axis.

[0017] Preferably, the membrane (10) and the flexible sheet one (501) and the flexible sheet two (502) in the flexible joint (5) are stacked in multiple pieces, so as to increase the flexibility.

[0018] Preferably, when the flexible sheet one (501) and the flexible sheet two (502) are arranged on both sides of the inner ring (503), four countersunk screws are arranged in a cross shape on both sides, and the initial angle of the countersunk screw on one side is 0°, and the initial angle of the countersunk screw on the other side is 45°.

[0019] Preferably, the raw material of the flexible joint (5) is titanium alloy material which has high strength and large flexibility.

[0020] Beneficial effects:

[0021] Since the traditional self-aligning ball bearing, ball head structure and slide bar have friction, the accuracy of the support force is reduced, thereby affecting the mirror surface precision. The flexible joint is used to replace the self-aligning ball bearing, and the membrane is used to replace the ball head structure and the slide bar, so that the flexible side support structure has the characteristics of no friction and no gap, can stably provide side support force, and reduce the influence of temperature change on the mirror surface. At the same time, the flexible side support structure can reduce the impact generated in the process of the main mirror moving from the horizontal to the vertical working condition, ensure the surface precision of the main mirror, and is suitable for telescopes under complex working conditions with large temperature difference.

[0022] Compared with the single-layer flexible joint structure without bending angle, the flexible joint structure can bear axial force, has large radial and axial rigidity, is located at the lever fulcrum position, and only has two rotation degrees of freedom around the x-axis and the y-axis. The flexible sheets can provide pulling force to the inner ring, thereby improving the ability of the flexible joint structure to bear radial load. The inner ring and the outer ring can bear axial load, thereby improving the ability of the flexible joint structure to bear axial load. The flexible joint structure plays a key role in reducing the temperature deformation difference of the mirror body and reducing the mechanical load at the support point caused by temperature. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1is the overall structure schematic diagram of the flexible side support structure of the reflecting mirror of the present application.

[0024] Figure 2 is the overall structure schematic diagram of the flexible joint of the present application.

[0025] Figure 3 is the sectional view of the flexible joint of the present application.

[0026] Figure 4 is the front view of the flexible sheet one in the flexible joint of the present application.

[0027] Figure 5 is the side view of the flexible sheet one in the flexible joint of the present application.

[0028] Figure 6 is the front view of the flexible sheet three of the present application.

[0029] Figure 7 is the front view of the diaphragm of the present application.

[0030] Figure 8 is the structure schematic diagram of the outer pressure ring of the flexible joint of the present application.

[0031] Figure 9 is the structure schematic diagram of the diaphragm seat of the present application.

[0032] Figure 10 is the structure schematic diagram of the inner pressure ring of the diaphragm of the present application.

[0033] Figure 11 is the structure schematic diagram of the installation positioning platform of the present application.

[0034] In the figure: 1, counterweight; 2, lever; 3, support; 4, inner pressure ring of flexible joint; 5, flexible joint; 6, outer pressure ring of flexible joint; 7, diaphragm seat; 8, outer pressure ring of diaphragm; 9, inner pressure ring of diaphragm; 10, diaphragm; 11, invar block; 12, main mirror; 13, flexible sheet three; 14, installation positioning platform; 501, flexible sheet one; 502, flexible sheet two; 503, inner ring; 504, inner pressure ring one; 505, inner pressure ring two; 506, outer ring; 507, outer pressure ring one; 508, outer pressure ring two. DETAILED DESCRIPTION

[0035] The present application will be further described in detail below in combination with the accompanying drawings.

[0036] Example 1

[0037] As Figure 1The mirror flexible side support structure is composed of a counterweight 1, a lever 2, a support 3, a flexible joint inner compression ring 4, a flexible joint 5, a flexible joint outer compression ring 6, a diaphragm seat 7, a diaphragm outer compression ring 8, a diaphragm inner compression ring 9, a diaphragm 10, a protective cover 11, an invar block 11 and a primary mirror 12.

[0038] In the embodiment, one end of the lever 2 is connected with the counterweight 1, the other end of the lever 2 is connected with the diaphragm seat 7 through the diaphragm 10, the diaphragm seat 7 is connected with the invar block 11, and the invar block 11 is cemented on the primary mirror 12. The flexible joint 5 is connected on the lever 2, and the flexible joint 5 is located at the position of the support point of the side support structure. The flexible joint inner compression ring 4 is in the shape of a circular ring, and the center is a threaded hole, which is threadedly connected with the lever 2. The flexible joint outer compression ring 6 is in the shape of a stepped circular ring, which can ensure that the contact surface is compressed tightly, and six circular holes are uniformly distributed on the circular ring, and the screw is connected through the circular hole and the threaded hole of the support 3.

[0039] The diaphragm inner compression ring 9 is in the shape of a stepped circular ring. The diaphragm outer compression ring 8 is in the shape of a circular ring, and six circular holes are uniformly distributed on the circular ring. The diaphragm 10 is in the shape of a circular ring, and six circular holes are uniformly distributed on the outer ring. Two groups of annular threaded holes are uniformly distributed on the diaphragm seat 7, and eight circular holes are distributed on the bottom of the diaphragm seat 7. The screw is connected through the circular hole of the diaphragm outer compression ring 8, the circular hole of the diaphragm 10 and one group of threaded holes of the diaphragm seat 7. The screw is connected with the diaphragm cover through the other group of threaded holes of the diaphragm seat 7.

[0040] In the embodiment, the length of the force arm on the lever 2 is adjusted, so that the support force provided by the side support balances the gravity of the primary mirror 12 distributed on the side support structure. In the embodiment, when the lens barrel points to the horizontal direction, the length of the force arm from the center of gravity of the primary mirror to the support point is 42 mm, and the total weight of the primary mirror is 939 kg. The total weight of the counterweight is 7 kg, and the length of the force arm from the center of gravity of the counterweight to the support point is 42 mm.

[0041]

[0042] In the embodiment, the inner ring of the diaphragm 10 is fixed through the diaphragm inner compression ring 9 and the lever 2, and the outer ring of the diaphragm 10 is fixed through the diaphragm seat 7 and the diaphragm outer compression ring 8.

[0043] In the embodiment, the inner ring 503 of the flexible joint 5 is fixed through the lever 2 and the flexible joint inner compression ring 4, and the outer ring 506 is fixed through the support 3 and the flexible joint outer compression ring 6.

[0044] In the embodiment, in order to reduce the thermal stress generated by the primary mirror 12, the invar block 11 with a thermal expansion coefficient close to that of the primary mirror 12 is cemented with the primary mirror 12.

[0045] In this embodiment, since the telescope support includes a bottom support and a side support, the bottom support is not a completely rigid structure, and the bottom support will deform during the movement of the telescope, thereby causing the mirror to produce axial displacement. In order to reduce the axial displacement and eliminate the friction, the flexible side support structure of the reflector uses a diaphragm 10 to replace the ball head structure and the sliding rod which exist friction. The diaphragm 10 is a circular ring, and the outer ring is uniformly distributed with six circular holes.

[0046] In this embodiment, in order to eliminate the friction and the gap, the flexible side support structure of the reflector uses a flexible joint 5 to replace the self-aligning ball bearing which exists friction. The optical performance of the telescope can be greatly improved.

[0047] The flexible joint 5 includes a flexible sheet one 501, a flexible sheet two 502, an inner ring 503, an inner pressure ring one 504, an inner pressure ring two 505, an outer ring 506, an outer pressure ring one 507, and an outer pressure ring two 508. The flexible joint 5 is rigid in axial and radial directions, and only has two rotational degrees of freedom around the x-axis and the y-axis. The inner ring 503 and the outer ring 506 can bear radial force and axial force.

[0048] In this embodiment, the diaphragm 10 and the flexible sheet one 501 and the flexible sheet two 502 in the flexible joint 5 adopt a multi-piece stacking mode for increasing flexibility. Four 0.025 mm flexible sheets are stacked together to become a 0.1 mm flexible sheet.

[0049] In this embodiment, the flexible sheet one 501 and the flexible sheet two 502 are the same in structure and size. The flexible sheet one 501 and the flexible sheet two 502 are each composed of four flexible sheets connected by a flexible sheet inner ring; the flexible sheet inner ring is annular, and a flexible sheet upper, a flexible sheet left, a flexible sheet lower, and a flexible sheet right are fixed in a cross form in the circumferential direction, and the included angle between adjacent two flexible sheets is 90 degrees; the flexible sheet one 501 and the flexible sheet two 502 are symmetrically arranged with the inner ring 503 as the center; the flexible sheet one 501 and the flexible sheet two 502 are obtained by twice bending of a flexible sheet three 13 at a certain angle θ relative to the xy plane, and form a planar middle protrusion. The center of the flexible sheet three 13 is composed of a circular ring, and eight circular holes are uniformly distributed in the annular direction of the circular ring, and the circular ring connects four groups of flexible sheets arranged in a cross form.

[0050] In this embodiment, the inner pressure ring one 504 and the inner pressure ring two 505 are the same in structure and size, and the outer pressure ring one 507 and the outer pressure ring two 508 are the same in structure and size, and are annular in shape.

[0051] The inner ring 503 is annular and uniformly distributed with eight threaded holes; the outer ring 506 is annular and uniformly distributed with eight threaded holes, the inner pressure ring one 504 and the inner pressure ring two 505 are annular and uniformly distributed with four countersunk holes; the outer pressure ring one 507 and the outer pressure ring two 508 are annular and uniformly distributed with eight countersunk holes; and the flexible sheet one 501 and the flexible sheet two 502 are annular and uniformly distributed with eight circular holes.

[0052] The inner pressure ring 504, the flexible sheet 501, the inner ring 503, the flexible sheet 502 and the inner pressure ring 505 are connected and positioned by the countersunk screws; the outer pressure ring 507, the flexible sheet 501, the outer ring 506, the flexible sheet 502 and the outer pressure ring 508 are connected and positioned by the countersunk screws.

[0053] When the flexible sheet 501 and the flexible sheet 502 are arranged on both sides of the inner ring 503 respectively, there are four countersunk screws on both sides, which are arranged in a cross form, and the initial angle of the countersunk screws on one side is 0°, and the initial angle of the countersunk screws on the other side is 45°.

[0054] In the embodiment, the flexible joint 5 is made of titanium alloy material which has large flexibility and high strength.

[0055] In the embodiment, the processing procedure of the flexible sheet 501 and the flexible sheet 502 is as follows: first, the flexible sheet 13 is processed by a machine tool, the center of the flexible sheet 13 is composed of a circular ring, there are eight circular holes uniformly distributed on the circular ring, and the circular ring is connected with four groups of flexible sheets arranged in a cross form. Then, the flexible sheet 501 and the flexible sheet 502 are obtained by twice bending at a certain angle θ with respect to the xy plane. The range of θ can be 10° to 30°, and in the embodiment, the angle value of θ is 15.8°.

[0056] In the embodiment, before the flexible joint 5 is installed, the surfaces of all parts are inspected and cleaned to ensure that the parts can be precisely fitted. When installing, the installation positioning platform 14 is prepared first, the center part of the installation positioning platform is composed of a stepped shaft, which is used for radial and axial positioning, and there are four circular holes uniformly distributed on the stepped shaft. There are eight circular holes uniformly distributed on the bottom of the installation positioning platform. The installation positioning platform has an outer ring, which is used for radial positioning.

[0057] The inner pressure ring 504 and the outer pressure ring 507 are placed in the installation positioning platform 14, the inner pressure ring 504 is radially positioned by the shaft of the installation positioning platform 14, and the outer pressure ring 507 is radially positioned by the outer ring of the installation positioning platform 14. Then, the flexible sheet 501, the inner ring 503, the outer ring 506, the flexible sheet 502, the inner pressure ring 505 and the outer pressure ring 508 are placed in sequence. Finally, the countersunk screws on the upper surface are installed, and the countersunk screws on the lower surface are installed through the holes in the bottom of the installation positioning platform 14, and the installation of the flexible joint 5 is completed.

[0058] Compared with the single-layer flexible joint structure without bending angle, the flexible joint structure can bear axial force and has large radial and axial stiffness.

[0059] The theoretical calculation of the radial stiffness of the two-degree-of-freedom flexible joint structure is as follows: the elastic modulus E of titanium alloy is 1.1×10 11Pa, the length of the flexible sheet L=15.58mm, the length of the flexible sheet in the xy plane projection is 15mm, the width b=4mm, the thickness t=0.1mm, first assume that the inner ring is displaced along the y direction Δy=0.01mm, the length of the flexible sheet is stretched flexibility the inner ring is subjected to a force along the y direction radial stiffness the radial stiffness obtained by simulation is close to the theoretical calculation result.

[0060] In the embodiment, due to insufficient assembly accuracy during installation, residual stress will be generated on the flexible side support structure of the reflector, and manual aging treatment needs to be performed on the parts to eliminate the residual stress and improve the accuracy.

Claims

1. A flexible side support structure for a reflector, characterized in that: The flexible side support structure of the reflector is composed of a counterweight (1), a lever (2), a support (3), a flexible joint inner pressure ring (4), a flexible joint (5), a flexible joint outer pressure ring (6), a diaphragm seat (7), a diaphragm outer pressure ring (8), a diaphragm inner pressure ring (9), a diaphragm (10), an Invar block (11), and a primary mirror (12). One end of the lever (2) is connected to the counterweight (1), and the other end of the lever (2) is connected to the diaphragm seat (7) through the diaphragm (10). The diaphragm seat (7) is connected to the Invar block (11), and the Invar block (11) is glued to the main mirror (12). The flexible joint (5) serves as the fulcrum of the lever (2). The inner ring of the diaphragm (10) is fixed by the inner pressure ring (9) and the lever (2), and the outer ring of the diaphragm (10) is fixed by the diaphragm seat (7) and the outer pressure ring (8); the inner ring (503) of the flexible joint (5) is fixed by the lever (2) and the inner pressure ring (4), and the outer ring (506) of the flexible joint (5) is fixed by the support (3) and the outer pressure ring (6); The flexible joint (5) includes flexible plate one (501), flexible plate two (502), inner ring (503), inner pressure ring one (504), inner pressure ring two (505), outer ring (506), outer pressure ring one (507) and outer pressure ring two (508); The flexible sheet one (501) and the flexible sheet two (502) have the same structure and size. They are composed of four flexible sheets arranged in a cross shape connected by the inner ring of the flexible sheet. They are all obtained by bending the flexible sheet three (13) twice at a certain angle θ relative to the xy plane. The flexible joint inner pressure ring (4) is in the shape of a ring with a threaded hole in the center, and is threadedly connected to the lever (2); the flexible joint outer pressure ring (6) is in the shape of a stepped ring, which can ensure that the contact surface is pressed tightly. The ring has evenly distributed round holes, and the screw is connected to the support (3) through the round holes. The inner pressure ring (9) of the diaphragm is a stepped ring shape; the outer pressure ring (8) of the diaphragm is a ring shape with evenly distributed round holes on the ring; the diaphragm (10) is a ring with evenly distributed round holes on the outer ring; the diaphragm seat (7) has two sets of annular threaded holes evenly distributed on it, and round holes are distributed at the bottom of the diaphragm seat (7). The screw is connected through the round holes of the outer pressure ring (8), the round holes of the diaphragm (10), and a set of threaded holes of the diaphragm seat (7); the screw is connected to the diaphragm cover through another set of threaded holes of the diaphragm seat (7). The flexible joint (5) used in the flexible side support structure of the reflector can eliminate friction and gaps and improve the accuracy of the support force; the flexible joint (5) is rigid in the axial and radial directions and has only two rotational degrees of freedom around the x-axis and y-axis; The flexible joint (5) is made of titanium alloy material with high flexibility and high strength.

2. The flexible side support structure for the reflector according to claim 1, characterized in that: By using an Invar block (11) with a thermal expansion coefficient close to that of the primary mirror (12) to bond with the primary mirror (12), the thermal stress generated by the primary mirror (12) can be reduced.

3. The flexible side support structure for the reflector according to claim 1, characterized in that: The diaphragm (10) used in the flexible side support structure of the mirror can eliminate friction and gaps, while reducing the axial displacement of the main mirror (12) caused by the stress on the bottom support.

4. The flexible side support structure for the reflector according to claim 1, characterized in that: The diaphragm (10) and the flexible joint (5) use multiple overlapping flexible sheet one (501) and flexible sheet two (502) to increase flexibility.

5. The flexible side support structure for the reflector according to claim 1, characterized in that: When the flexible sheet one (501) and the flexible sheet two (502) are respectively arranged on both sides of the inner ring (503), there are 4 countersunk screws on both sides arranged in a cross shape, and when the starting angle of the countersunk screw on one side is 0°, the starting angle of the countersunk screw on the other side is 45°.

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