Optical telescope primary mirror assembly and anti-backlash close-fitting method thereof

Abstract

The invention discloses an optical telescope primary mirror assembly and an anti-backlash close-fitting method thereof. The primary mirror assembly comprises a telescope primary mirror, a primary mirror mounting seat, a central mandrel, a pressing ring and a plurality of copper sheets. The primary mirror mounting seat is coaxially connected with the central mandrel through a screw and a positioning pin; the primary mirror of the telescope is embedded in the primary mirror mounting seat, and the central spindle penetrates through the central through hole of the primary mirror to finish coarse positioning of the primary mirror in the primary mirror mounting seat. A plurality of equal-thickness copper sheets are inserted into a circular gap between the central mandrel and the central through hole of the primary mirror at equal intervals, so that accurate positioning of the primary mirror in the primary mirror mounting seat is completed while the gap is eliminated. And a ball fastener is screwed into the threaded through hole in the side wall of the central mandrel, and the head of the fastener abuts against the corresponding copper sheet to realize interference fit. According to the design method, the assembled primary mirror assembly can be completely stable, the stress in all directions is uniform, the extrusion stress can be well conducted after the gravity posture is changed, and the good surface precision of the primary mirror is maintained.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of aerospace optical telescope manufacturing integration, and particularly relates to an optical telescope main mirror assembly and a gap-eliminating and tight-fitting method thereof. BACKGROUND

[0002] In the prior art, the main mirror is the most critical and usually the largest optical component in an optical telescope, and undertakes the task of collecting weak photons from a remote target and converging light, which directly determines the upper limit of the resolution capability of the telescope and the basic configuration of the entire optical-mechanical imaging system.

[0003] The main mirror is in a gravity attitude in its machining detection and combined support with structural members, and when the gravity direction changes relative to the attitude of the main mirror, extrusion stress is generated at different positions of the main mirror, so that the mirror surface is locally deformed slightly; and in order to ensure the imaging quality of the system, the main mirror reflecting surface of the mainstream telescope is generally designed as a standard hyperboloid or a high-order aspheric surface, and the machining precision requirement is at least 1 / 50 lambda RMS; slight deformation can easily lead to the surface type of the main mirror to be out of tolerance and the performance to be degraded.

[0004] A Chinese patent with the publication number CN105511050A discloses an elastic center support structure of a reflecting mirror, which comprises a center core shaft, a threaded nest, an M3 screw and a threaded pressing ring. The threaded nest is glued and fixed in the outer circumferential sink hole of the center core shaft, and the M3 screw is screwed into the threaded nest. The center core shaft is fixed on a mounting back plate, the elastic blades of the center core shaft are tightened by tightening the M3 screw, the outer circle size of the center core shaft is smaller than the inner hole of the reflecting mirror, the center core shaft is placed in the inner hole of the reflecting mirror, and the elastic blades of the center core shaft are expanded by loosening the M3 screw, so as to be tightly matched with the reflecting mirror in interference. The threaded pressing ring one and the threaded pressing ring two are screwed from the top of the center core shaft and are pressed against the step surface of the reflecting mirror.

[0005] The above patent sets a plurality of elastic blades fixed with the center core shaft on the outer circle of the center core shaft, and sets a screw threaded with the center core shaft. In the installation state, the elastic blades can be tightened by the screw, so that the main mirror can be smoothly sleeved on the outer circle of the center core shaft. Then the screw is screwed outward, so that the elastic blades in tension are released and reset, filling the gap between the center core shaft and the main mirror, so as to avoid the change of the position of the main mirror in the use process due to the existence of the gap.

[0006] However, the combination of the elastic blade and the center shaft in the above structure design requires high processing and manufacturing of the two and complex assembly; more importantly, the elastic force of the elastic blade is not stable enough to fix the spatial position of the primary mirror in the radial direction, firstly depending on the mass and service life of the elastic blade, and secondly the primary mirror is easily affected by vibration or impact to change the spatial position, and the relative position change of the optical element in the space telescope easily causes the imaging quality to be seriously reduced. SUMMARY

[0007] In order to make up for the shortcomings of the prior art, the optical telescope primary mirror assembly and the gap-eliminating tight fitting method thereof are provided to solve the technical problems of complex assembly, high difficulty and instability caused by ensuring the unchanged mirror surface when the primary mirror of the telescope is assembled.

[0008] To achieve the above object, the specific technical solutions of the present application are as follows: In a first aspect, an optical telescope primary mirror assembly includes a telescope primary mirror, a primary mirror mounting seat, a center shaft, a compression ring and multiple copper sheets. The primary mirror mounting seat is used to carry the telescope primary mirror and is connected with the external telescope optical machine frame.

[0009] The center shaft is fixed on the primary mirror mounting seat and is used to coarsely position the position of the telescope primary mirror in the primary mirror mounting seat.

[0010] The telescope primary mirror is embedded in the primary mirror mounting seat, and the center through hole is gap-fitted with the center shaft.

[0011] Each copper sheet is inserted in the gap between the center shaft and the telescope primary mirror in sequence. The center shaft is provided with multiple fasteners corresponding to each copper sheet. Each fastener is embedded in the side wall of the center shaft by relying on the thread rotation, and can move inward or outward along the tangential direction perpendicular to the outer wall of the center shaft during rotation.

[0012] The compression ring is sleeved on the top of the center shaft and is threadedly connected with the center shaft, and is used to fix the position of the telescope primary mirror on the primary mirror mounting seat along the optical axis direction.

[0013] Further, a one-side open mounting chamber is formed in the primary mirror mounting seat. The telescope primary mirror is embedded in the mounting chamber. The bottom surface of the mounting chamber is in close contact with the bottom of the telescope primary mirror.

[0014] Further, multiple rows of glue injection through holes are formed in the side wall of the primary mirror mounting seat and are distributed in a ring shape.

[0015] Further, an outwardly extending flange is arranged on the outer edge of the primary mirror mounting seat. A screw through hole is arranged on the flange and can be connected with the external telescope optical machine body.

[0016] Further, the telescope main mirror is a central rotationally symmetrical annular body. A central through hole is formed in the center of the telescope main mirror and matched with the central shaft. The central shaft passes through the central through hole and is fixedly connected with the main mirror mounting seat at the bottom.

[0017] Further, the central shaft is in a cylindrical structure and a regulating chamber is formed in the center. A plurality of rows of threaded through holes are arranged on the side wall of the central shaft. The threaded through holes in each row are evenly distributed in a ring shape at equal intervals along the side wall of the central shaft. Each fastener is threadedly fitted into the corresponding threaded through hole and the head portion passes through the threaded through hole and abuts against the copper sheet.

[0018] Further, the head portion of the fastener is in a circular ball head structure.

[0019] Further, the copper sheet is in an arc-shaped sheet structure, and the two side surfaces are divided into an inscribed surface and an circumscribed surface. The diameter of the arc of the inscribed surface is the same as the outer diameter of the central shaft, and the diameter of the arc of the circumscribed surface is the same as the inner diameter of the central through hole of the telescope main mirror.

[0020] Further, a limiting step surface matched with the compression ring is arranged on the telescope main mirror. The compression ring can be pressed against the limiting step surface when being screwed.

[0021] The second aspect is a gap-eliminating and tight-fitting method of an optical telescope main mirror assembly, and the specific steps are as follows: Step 1, fixing the central shaft in the mounting chamber of the main mirror mounting seat.

[0022] Step 2, embedding the telescope main mirror in the mounting chamber of the main mirror mounting seat. The central through hole of the telescope main mirror is sleeved on the outer circle of the central shaft, and the inner wall is gap-fitted with the outer wall of the central shaft.

[0023] Step 3, inserting a plurality of copper sheets between the outer wall of the central shaft and the inner wall of the central through hole of the telescope main mirror from top to bottom, and the copper sheets are distributed in a ring shape at equal intervals.

[0024] Step 4, screwing the fasteners into the threaded through holes on the central shaft. The outer ends of each fastener respectively abut against the corresponding copper sheet.

[0025] Step 5, screwing the compression ring on the top of the central shaft, and the outer circle edge forms a position limitation for the telescope main mirror.

[0026] Step 6, injecting the anti-loosening glue into the glue injection through hole of the main mirror mounting seat for bonding the side wall of the telescope main mirror and the inner wall of the main mirror mounting seat.

[0027] Compared with the prior art, the present application has the following advantages: Firstly, the method of using a circular arc copper sheet to eliminate the gap between the central mandrel and the main mirror central through hole does not have complex assembly links, only requires that the contact surface of each component is good in cylindricality and the wall surface is smooth, and is friendly to processing and manufacturing. Secondly, the method of using a threaded embedded rotating fastener can better control the jacking pressure of each fastener on the copper sheet, and through control of the rotation degree, the central through hole of the main mirror can be uniformly stressed and the radial position is stable. Finally, the combination of uniform stress of the central hole and adhesion of the outer wall enables the main mirror assembly to maintain a good surface shape after the gravity acting on different position points due to change of the posture. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a schematic diagram of the overall structure of the present application; Figure 2 is a schematic diagram of the structure of the main mirror mounting seat in the present application; Figure 3 is a schematic diagram of the structure of the main mirror of the telescope in the present application; Figure 4 is a schematic diagram of the structure of the central mandrel in the present application; Figure 5 is a schematic diagram of the relative position of the central mandrel and the main mirror of the telescope during installation in the present application; Figure 1 is a partial enlarged view of part A; Figure 6 is a schematic diagram of the structure of the copper sheet in the present application; Figure 7 is a schematic diagram of the structure of the pressing ring in the present application.

[0029] Reference signs: 1, main mirror of telescope; 1-1, central through hole; 1-2, optical surface; 1-3, fixed surface; 2, main mirror mounting seat; 2-1, positioning surface; 2-2, glue injection through hole; 2-3, flange; 3, central mandrel; 3-1, threaded through hole; 3-2, external thread; 4, copper sheet; 4-1, inner contact surface; 4-2, outer contact surface; 5, pressing ring; 5-1, internal thread. DETAILED DESCRIPTION

[0030] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "one end", "the other end", "outer side", "upper", "inner side", "horizontal", "coaxial", "central", "end", "length", "outer end" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0031] The present application will be further described below in conjunction with the drawings.

[0032] AsFigure 1 As shown in the drawings, an optical telescope primary mirror 1 assembly comprises a telescope primary mirror 1, a primary mirror mounting seat 2, a central core shaft 3, a pressing ring 5 and a plurality of copper sheets 4. The primary mirror mounting seat 2 is used to carry the telescope primary mirror 1 and is connected with the external telescope optical machine frame. The central core shaft 3 is fixed on the primary mirror mounting seat 2 and is used to coarsely position the position of the telescope primary mirror 1 in the primary mirror mounting seat 2.

[0033] The telescope primary mirror 1 is embedded on the primary mirror mounting seat 2 and is in clearance fit with the central core shaft 3. Each copper sheet 4 is inserted in the clearance between the central core shaft 3 and the telescope primary mirror 1 in sequence. A plurality of fasteners corresponding to each copper sheet 4 are arranged on the side wall of the central core shaft 3. Each fastener is embedded in the side wall of the central core shaft 3 by screwing and can move inward or outward along the tangential direction perpendicular to the outer wall of the central core shaft 3 during rotation. By screwing the fastener outward, the outer end of the fastener is pressed outward to tightly fit with the corresponding copper sheet 4 and the telescope primary mirror 1, so as to eliminate the small gap between the central core shaft 3 and the telescope primary mirror 1.

[0034] The pressing ring 5 is sleeved on the top of the central core shaft 3 and is in threaded fit with the central core shaft 3, which is used to fix the position of the telescope primary mirror 1 on the primary mirror mounting seat 2 along the optical axis direction.

[0035] As shown in the drawings, Figure 1 and Figure 2 The primary mirror mounting seat 2 is in the form of a basin body as a whole. The primary mirror mounting seat 2 is provided with a one-side open mounting chamber. The bottom surface of the mounting chamber forms a positioning surface 2-1 matched with the telescope primary mirror 1. The telescope primary mirror 1 is embedded in the mounting chamber and the bottom thereof is attached to the positioning surface 2-1. A plurality of rows of injection glue through holes 2-2 are arranged on the side wall of the primary mirror mounting seat 2 in the form of annular distribution with equal intervals. After the installation and gap elimination of the telescope primary mirror 1 are completed, the staff member injects the anti-loosening glue into the injection glue through holes, so as to further fix the telescope primary mirror 1 by bonding the side wall of the telescope primary mirror 1 and the inner wall of the primary mirror mounting seat 2.

[0036] Further, the outer edge of the primary mirror mounting seat 2 is provided with an outwardly extending flange 2-3. The flange 2-3 is provided with screw through holes connected with the external telescope optical machine body.

[0037] As shown in the drawings, Figure 3 The telescope primary mirror 1 is a central rotationally symmetrical annular body. The center of the telescope primary mirror 1 is provided with a central through hole 1-1 matched with the central core shaft 3. The central core shaft 3 passes through the central through hole 1-1 and the bottom thereof is fixedly connected with the primary mirror mounting seat 2.

[0038] Further, the two side surfaces of the main mirror 1 of the telescope are divided into the optical surface 1-2 on the front side and the fixed surface 1-3 on the back side. The surface shape of the optical surface 1-2 can adopt one of a parabolic surface, a hyperbolic surface, a high-order aspheric surface, a spherical surface, or a free-form surface. The fixed surface 1-3 is provided with lightened grooves to reduce the overall weight of the main body of the telescope.

[0039] As shown in Figure 4 and Figure 5 , the central core shaft 3 is in a cylindrical structure, and a regulating cavity is provided in the center, so that the staff has sufficient operating space to install the fastener on the central core shaft 3. The side wall of the central core shaft 3 is provided with a plurality of rows of threaded holes 3-1. Each row of threaded holes 3-1 is uniformly distributed along the side wall of the central core shaft 3 at equal intervals. Each fastener is respectively threadedly fitted into the corresponding threaded hole 3-1, and the head portion penetrates through the threaded hole 3-1 and abuts against the copper sheet 4. By pressing the copper sheet 4, the interference fit between the central core shaft 3 and the main mirror 1 of the telescope is realized.

[0040] In this embodiment, the fastener can adopt a standard type ball head screw or a self-designed ball head screw structure. The fastener is divided into a ball head portion at the outer end and a main body portion at the tail end. The ball head portion is in a whole circular ball head structure, and the main body portion is in a whole cylindrical structure.

[0041] Further, a connecting groove is provided at the top edge of the central core shaft 3. An outer thread 3-2 is provided on the side wall of the connecting groove and cooperates with the pressing ring 5. An inner thread 5-1 is provided on the inner wall of the pressing ring 5 and cooperates with the outer thread 3-2. The cooperation between the outer thread 3-2 and the inner thread 5-1 realizes the threaded cooperation between the pressing ring 5 and the central core shaft 3. The positioning step surface is used to limit the limit position of the downward rotation of the pressing ring 5, so as to avoid the pressing ring 5 from continuously rotating downward and exerting pressure on the main mirror 1 of the telescope, causing the deformation of the main mirror 1.

[0042] As shown in Figure 6 , the copper sheet 4 is in an arc-shaped sheet structure, and its two side surfaces are divided into an inner tangent surface 4-1 and an outer tangent surface 4-2. The diameter of the circular arc of the inner tangent surface 4-1 is the same as the outer diameter of the central core shaft 3, and the diameter of the circular arc of the outer tangent surface 4-2 is the same as the inner diameter of the central through hole 1-1 of the main mirror 1 of the telescope.

[0043] As shown in Figure 7 , the whole pressing ring 5 is in a ring structure. The main mirror 1 of the telescope is provided with a limiting step surface cooperating with the pressing ring 5. The pressing ring 5 can be pressed against the limiting step surface during the tightening, so as to fix the position of the main mirror 1 of the telescope on the main mirror mounting seat 2 along the optical axis direction.

[0044] In some embodiments, the telescope main mirror 1 is made of silicon carbide; the main mirror mounting seat 2, the center shaft 3 and the pressing ring 5 are made of titanium alloy; and the copper sheet 4 is made of red copper or oxygen-free copper.

[0045] The application also provides a method for eliminating the gap of the optical telescope main mirror 1 assembly, and the specific steps are as follows. Step 1, the center shaft 3 is installed in the installation cavity of the main mirror mounting seat 2, and is fixedly connected through screws and positioning pins.

[0046] Step 2, the telescope main mirror 1 is embedded in the installation cavity of the main mirror mounting seat 2. The center through hole 1-1 on the telescope main mirror 1 is sleeved on the outer ring of the center shaft 3, and the inner wall is gap-fitted with the outer wall of the center shaft 3.

[0047] Step 3, a plurality of copper sheets 4 are inserted from top to bottom between the outer wall of the center shaft 3 and the inner wall of the center through hole 1-1 of the telescope main mirror 1. Each copper sheet 4 is distributed in a ring shape at equal intervals, corresponding to the distribution position of each row of threaded holes 3-1 on the center shaft 3.

[0048] In this embodiment, before the copper sheet 4 is inserted, the staff member applies a layer of anti-loosening glue to the inner contact surface 4-1 of the copper sheet 4 and the center shaft 3, so as to prevent the position of the copper sheet 4 from being dislocated in the subsequent installation process.

[0049] Step 4, the ball head screw fastener is screwed into the threaded hole 3-1 on the center shaft 3. The ball head of the ball head screw passes through the threaded hole 3-1 and tightly presses the copper sheet 4, and the main body part extends into the threaded hole. At the same time, the tightening degree of each ball head screw is kept consistent to ensure that the extrusion force of the tightly pressed copper sheet 4 is consistent. Then, the anti-loosening glue is injected into the threaded hole 3-1 to prevent the ball head screw from loosening.

[0050] Step 5, the pressing ring 5 is screwed on the top of the center shaft 3, and the screwing is stopped when the pressing ring 5 is screwed down to contact the limiting step surface on the telescope main mirror 1. Then, the epoxy glue is applied to the contact position between the inner thread 5-1 of the pressing ring 5 and the outer thread 3-2 of the center shaft 3 to completely fix the pressing ring 5.

[0051] Step 6, the anti-loosening glue is injected at the glue injection hole 2-2 of the main mirror mounting seat 2 to bond the side wall of the telescope main mirror 1 and the inner wall of the main mirror mounting seat 2, so as to further fix the position of the telescope main mirror 1 in the mounting seat.

[0052] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit the present application; although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions recorded in the above embodiments can be modified, or some or all of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. An optical telescope primary mirror assembly comprising a telescope primary mirror, a primary mirror mount, a central spindle, a compression ring, characterized in that: It also includes multiple copper sheets; the main mirror mounting seat is used for carrying the telescope main mirror and connecting with the external telescope optical machine frame; The center mandrel is fixed on the main mirror mounting seat and used for roughly positioning the position of the telescope main mirror in the main mirror mounting seat; The telescope main mirror is embedded on the main mirror mounting seat, and the center through hole is gap-fitted with the center mandrel; Each copper sheet is inserted between the center mandrel and the telescope main mirror in sequence; the center mandrel is provided with multiple fasteners corresponding to each copper sheet; each fastener is embedded in the side wall of the center mandrel by rotating the thread and can move inward or outward along the tangent direction perpendicular to the outer wall of the center mandrel during rotation; The pressing ring is sleeved on the top of the center mandrel and is threadedly connected with the center mandrel, and is used for fixing the position of the telescope main mirror on the main mirror mounting seat along the optical axis direction.

2. An optical telescope primary mirror assembly according to claim 1, wherein: The main mirror mounting seat is provided with an open installation chamber on one side; the telescope main mirror is embedded in the installation chamber; the bottom surface of the installation chamber is in close contact with the bottom of the telescope main mirror.

3. An optical telescope primary mirror assembly according to claim 2, wherein: Multiple rows of injection glue through holes are arranged on the side wall of the main mirror mounting seat in equal intervals.

4. An optical telescope primary mirror assembly as claimed in claim 1, wherein: An outwardly extending flange is arranged on the outer edge of the main mirror mounting seat; a screw through hole is arranged on the flange and connected with the external telescope optical machine body.

5. An optical telescope primary mirror assembly as claimed in claim 3, wherein: The telescope main mirror is a central rotationally symmetrical annular body; the center of the telescope main mirror is provided with a center through hole matched with the center mandrel; the center mandrel passes through the center through hole and is fixedly connected with the main mirror mounting seat at the bottom.

6. An optical telescope primary mirror assembly as claimed in claim 1, wherein: The center mandrel is in a cylindrical structure and is provided with an adjusting chamber in the center; multiple rows of threaded through holes are arranged on the side wall of the center mandrel; each row of threaded through holes is arranged in equal intervals in a circular manner along the side wall of the center mandrel; each fastener is threadedly fitted with the corresponding threaded through hole and the head passes through the threaded through hole and abuts against the copper sheet.

7. An optical telescope primary mirror assembly as claimed in claim 1, wherein: The head of the fastener adopts a circular ball head structure.

8. An optical telescope primary mirror assembly as claimed in claim 5, wherein: The copper sheet is an arc-shaped sheet structure, and its two side surfaces are divided into an inscribed surface and an circumscribed surface; the diameter of the arc of the inscribed surface is the same as the outer diameter of the center mandrel; the diameter of the arc of the circumscribed surface is the same as the inner diameter of the center through hole of the telescope main mirror.

9. An optical telescope primary mirror assembly as claimed in claim 1, wherein: The telescope main mirror is provided with a limiting step surface matched with the pressing ring; the pressing ring can be pressed against the limiting step surface when being screwed.

10. The method of claim 5, wherein: The specific steps are as follows: Step 1, fix the center mandrel in the installation chamber of the main mirror mounting seat; Step 2, embed the telescope main mirror in the installation chamber of the main mirror mounting seat; the center through hole of the telescope main mirror is sleeved on the outer ring of the center mandrel, and the inner wall is gap-fitted with the outer wall of the center mandrel; Step 3, insert multiple copper sheets between the outer wall of the center mandrel and the inner wall of the center through hole of the telescope main mirror from top to bottom, and the copper sheets are arranged in equal intervals in a circular manner; Step 4, screw the fastener into the threaded through hole on the center mandrel; the outer end of each fastener abuts against the corresponding copper sheet; Step 5, screw the pressing ring on the top of the center mandrel, and the outer edge forms a position limitation for the telescope main mirror; Step 6, inject the anti-loosening glue into the glue injection through hole of the main mirror mounting seat, and use it to bond the side wall of the telescope main mirror and the inner wall of the main mirror mounting seat.

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