Coaxial Cassegrain reflective antenna with stable structure

Abstract

The utility model relates to a coaxial Cassegrain reflective antenna with a stable structure. The coaxial Cassegrain reflective antenna comprises a primary mirror, a primary mirror bracket, a secondary mirror, a secondary mirror bracket, a focusing pad and an antenna main supporting seat, a connecting surface is arranged at the bottom of the antenna main supporting seat, a through cylindrical groove is formed in the connecting surface, one end of the cylindrical groove is connected with a primary mirror bracket, the primary mirror is arranged in the primary mirror bracket, the other end of the cylindrical groove is connected with a secondary mirror bracket through a focusing pad, the secondary mirror is arranged in the secondary mirror bracket, and the focusing pad is arranged on the secondary mirror bracket. And the focal lengths of the primary mirror and the secondary mirror are coaxial. According to the utility model, the structure is stable, the deformation influence caused by a certain fastener structure is eliminated through the arrangement of the strip-shaped holes, and it is ensured that no large position error occurs between lenses; the focusing pad is used for correcting errors and guaranteeing the lens position accuracy; the thermal expansion coefficients of the materials of the primary mirror bracket and the secondary mirror bracket and the materials of the two lenses are similar, so that the relative positions of the lenses can be prevented from being changed due to expansion, and the accuracy is guaranteed.

Description

Technical Field

[0001] The utility model relates to a reflective antenna, in particular to a coaxial Cassegrain reflective antenna with stable structure. Background Art

[0002] In the field of aerospace technology, star-measuring devices based on the principle of Cassegrain optical system are widely used. Such Cassegrain optical systems have extremely high precision requirements, but the use environment is often very harsh, and they have to withstand large temperature changes and strong vibrations, which will cause changes in the relative positions and postures of the primary and secondary mirrors, reducing the precision of the optical system. The current main structures mainly have the following problems:

[0003] Due to the tightness of the fasteners and partial deformation of the lens bracket, stress deformation will occur, resulting in changes in the relative positions of the two lenses;

[0004] When the two lenses are installed, the lens focusing is inaccurate due to reasons such as the roughness of the casting and fasteners;

[0005] The difference in the thermal expansion coefficients between the bracket and the lens is relatively large, and the positions of the two lenses change due to temperature changes. Summary of the Invention

[0006] The purpose of the utility model is to overcome the above deficiencies and provide a coaxial Cassegrain reflective antenna with stable structure, so that the antenna has high accuracy during use and is not easily deformed by external environment.

[0007] According to the technical solution provided by the utility model, a coaxial Cassegrain reflective antenna with stable structure includes a primary mirror, a primary mirror bracket, a secondary mirror, a secondary mirror bracket, a focusing pad and an antenna main support seat; a connecting surface is arranged at the bottom of the antenna main support seat, a through cylindrical groove is arranged above the connecting surface, one end of the cylindrical groove is connected with the primary mirror bracket, the primary mirror is arranged in the primary mirror bracket, the other end of the cylindrical groove is connected with the secondary mirror bracket through the focusing pad, the secondary mirror is arranged in the secondary mirror bracket, and the focal lengths of the primary mirror and the secondary mirror are coaxial.

[0008] As a further improvement of the utility model, the primary mirror bracket is of annular structure, three first lifting lugs are evenly distributed on its outer side surface, bolt holes are arranged on the first lifting lugs for fixing with the antenna main support seat; a plurality of through circular holes are evenly distributed on the outer side surface of the primary mirror bracket.

[0009] As a further improvement of the utility model, a through first strip-shaped hole is arranged on the first lifting lug, and the position of the first strip-shaped hole is below the bolt hole.

[0010] As a further improvement of the present utility model, the secondary mirror bracket is of an annular structure, with three second lifting lugs evenly distributed on its outer side. Bolt holes are provided on the second lifting lugs for fixing to the main support seat of the antenna; an annular secondary mirror mounting groove is provided in the middle of the secondary mirror bracket, and the outer side of the secondary mirror mounting groove is connected to the inner side of the secondary mirror bracket through three connecting columns that are 120° to each other.

[0011] As a further improvement of the present utility model, a through hole is provided on the outer side surface of the secondary mirror mounting groove.

[0012] As a further improvement of the present utility model, a second strip-shaped hole is provided on the second lifting lug, and the position of the second strip-shaped hole is below the bolt hole.

[0013] As a further improvement of the present utility model, the focusing pad is of an annular structure, and a grinding layer is provided on the focusing pad, and the grinding layer is provided to protrude outside the annular structure.

[0014] As a further improvement of the present utility model, both the primary mirror bracket and the secondary mirror bracket are made of invar material.

[0015] The beneficial effects of the present utility model are as follows:

[0016] The structure of the present utility model is stable. Through the setting of the strip-shaped holes, the deformation influence brought by a certain fastener structure is eliminated, ensuring that there is no large position error between the lenses; the setting of the focusing pad is used to correct the error through the grinding process of the grinding layer when there is an error during installation, ensuring the position accuracy of the lenses; the primary mirror bracket and the secondary mirror bracket are made of invar, and the thermal expansion coefficient between its material and the materials of the two lenses is similar, which can prevent the relative position of the lenses from changing due to expansion, ensuring accuracy. Brief Description of the Drawings

[0017] Figure 1 is the overall structure schematic diagram of the present utility model.

[0018] Figure 2 is the schematic diagram of the primary mirror bracket of the present utility model.

[0019] Figure 3 is the schematic diagram of the secondary mirror bracket of the present utility model.

[0020] Figure 4 is the schematic diagram of the focusing pad of the present utility model.

[0021] Figure 5 is the schematic diagram of the main support seat of the antenna of the present utility model.

[0022] Description of reference numerals: 1, primary mirror; 2, primary mirror support; 3, secondary mirror; 4, secondary mirror support; 5, main antenna support base; 6, focusing pad; 21, first lifting lug; 22, circular hole; 41, second lifting lug; 42, secondary mirror mounting groove; 43, connecting column; 44, hole; 45, second strip-shaped hole; 51, grinding layer. Detailed implementation manners

[0023] The following will further describe the present utility model in combination with the embodiments in the drawings:

[0024] As shown in the figure, a coaxial Cassegrain reflector antenna with stable structure includes a primary mirror 1, a primary mirror support 2, a secondary mirror 3, a secondary mirror support 4, a focusing pad 6 and a main antenna support base 5; a connecting surface 51 is provided at the bottom of the main antenna support base 5, the connecting surface 51 is a smooth plane, and screw holes are provided thereon for connecting and fixing with other components. A through cylindrical groove 52 is provided above the connecting surface 51. One end of the cylindrical groove 52 is connected to the primary mirror support 2, the primary mirror 1 is arranged in the primary mirror support 2, the other end of the cylindrical groove 52 is connected to the secondary mirror support 4 through the focusing pad 6, the secondary mirror 3 is arranged in the secondary mirror support 4, and the focal lengths of the primary mirror 1 and the secondary mirror 3 are coaxial.

[0025] The primary mirror support 2 is of an annular structure, and three first lifting lugs 21 are evenly distributed on its outer side surface. Bolt holes are provided on the first lifting lugs 21 for fixing with the main antenna support base 5; a plurality of through circular holes 22 are evenly distributed on the outer side surface of the primary mirror support 2; a through first strip-shaped hole 23 is provided on the first lifting lug 21, and the position of the first strip-shaped hole 23 is below the bolt hole. The function of the first strip-shaped hole 23 is to eliminate certain stress influence and play a buffering role for the primary mirror support 2.

[0026] The secondary mirror support 4 is of an annular structure, and three second lifting lugs 41 are evenly distributed on its outer side. Bolt holes are provided on the second lifting lugs 41 for fixing with the main antenna support base 5; an annular secondary mirror mounting groove 42 is provided in the middle of the secondary mirror support 4. The outer side of the secondary mirror mounting groove 42 is connected to the inner side of the secondary mirror support 4 through three connecting columns 43 that are 120° to each other; a through hole 44 is provided on the outer side surface of the secondary mirror mounting groove 42; a second strip-shaped hole 45 is provided on the second lifting lug 41, and the position of the second strip-shaped hole 45 is below the bolt hole. The function of the second strip-shaped hole 45 is to eliminate certain stress influence and play a buffering role for the secondary mirror support 4.

[0027] The focusing pad 6 is of an annular structure, and a grinding layer 61 is provided on the focusing pad 6. The grinding layer 61 is provided to protrude outside the annular structure. During alignment, three grinding layers 61 are ground by a grinding device to adjust the coaxiality and focal length of the secondary mirror 3 and the primary mirror 1.

[0028] Both the primary mirror support 2 and the secondary mirror support 4 are made of invar material. The materials of the primary mirror 1 and the secondary mirror 3 are N-BK7. The thermal expansion coefficients of the invar material and the primary mirror 1 and the secondary mirror 3 are similar. This is mainly because the material additives of invar can be adjusted to make its thermal expansion coefficient similar to that between the two lenses, so as to prevent deformation between the lens and the support caused by temperature, thereby affecting the position of the lens.

[0029] The circular holes 22 and the holes 45 are both glue injection holes, which are respectively used to glue the primary mirror 1 and the secondary mirror 3 onto the support.

Claims

1. A coaxial Cassegrain reflective antenna with a stable structure, characterized in that: The invention comprises a primary mirror (1), a primary mirror bracket (2), a secondary mirror (3), a secondary mirror bracket (4), a focusing pad (6) and an antenna main support seat (5); the bottom of the antenna main support seat (5) is provided with a connecting surface (51), a penetrating cylindrical groove (52) is provided on the connecting surface (51), one end of the cylindrical groove (52) is connected to the primary mirror bracket (2), the primary mirror (1) is arranged in the primary mirror bracket (2), the other end of the cylindrical groove (52) is connected to the secondary mirror bracket (4) through the focusing pad (6), the secondary mirror (3) is arranged in the secondary mirror bracket (4), and the focal lengths of the primary mirror (1) and the secondary mirror (3) are coaxial.

2. A structurally stable coaxial Cassegrain reflective antenna as claimed in claim 1, characterized in that: The main mirror bracket (2) is an annular structure, and three first lifting ears (21) are evenly distributed on its outer side surface. The first lifting ears (21) are provided with bolt holes for fixing to the antenna main support seat (5); and a plurality of penetrating circular holes (22) are evenly distributed on the outer side surface of the main mirror bracket (2).

3. A structurally stable coaxial Cassegrain reflective antenna as claimed in claim 2, characterized in that: The first lifting ear (21) is provided with a penetrating first strip-shaped hole (23), and the first strip-shaped hole (23) is located below the bolt hole.

4. A structurally stable coaxial Cassegrain reflective antenna as claimed in claim 1, characterized in that: The secondary mirror bracket (4) is an annular structure, and three second lifting ears (41) are evenly distributed on its outer side, and the second lifting ears (41) are provided with bolt holes for fixing to the antenna main support seat (5); an annular secondary mirror mounting groove (42) is provided in the middle of the secondary mirror bracket (4), and the outer side of the secondary mirror mounting groove (42) is connected to the inner side of the secondary mirror bracket (4) through three connecting columns (43) that are 120 degrees to each other.

5. A structurally stable coaxial Cassegrain reflective antenna as claimed in claim 4, characterized in that: The outer side surface of the secondary mirror mounting groove (42) is provided with a through hole (44).

6. A structurally stable coaxial Cassegrain reflective antenna as claimed in claim 4, characterized in that: The second lifting ear (41) is provided with a second strip-shaped hole (45), and the second strip-shaped hole (45) is located below the bolt hole.

7. The structurally stable coaxial Cassegrain reflective antenna according to claim 1, characterized in that: The focusing pad (6) is an annular structure, and a grinding layer (61) is provided on the focusing pad (6), wherein the grinding layer (61) is arranged to protrude outside the annular structure.

8. The structurally stable coaxial Cassegrain reflective antenna according to claim 1, characterized in that: The primary mirror bracket (2) and the secondary mirror bracket (4) are both made of Invar material.

Images