Parabolic antenna device and method for manufacturing the same

Abstract

To provide a parabolic antenna device that can be easily assembled even without a center dividing body.SOLUTION: A parabolic antenna device includes a parabolic reflector 2 that is formed in a bowl shape and has a concave reflecting surface 12, and is formed with a through hole 14 in the center of the reflecting surface, an antenna base 3 arranged on the outer surface 13 side of the parabolic reflector and having a flat surface 31 orthogonal to the axial direction of the through hole, and a positioning insertion portion 4 fixed to the antenna base and formed into a column shape extending in a direction perpendicular to the flat surface and inserted into the through hole. The parabolic reflector includes a plurality of circumferentially divided bodies 20 arranged in the circumferential direction thereof and each having an inner edge surface 201 that constitutes a part of the inner circumferential surface 15 of the through hole in the circumferential direction. The positioning insertion portion has an outer circumferential surface 41 that faces the inner circumferential surface when inserted into the through hole. The antenna base includes a holding portion 34 that holds the plurality of circumferentially divided bodies.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a parabolic antenna device and a method for manufacturing a parabolic antenna device. [Background technology]

[0002] Parabolic antenna devices are used in weather radars, satellite communications, radio telescopes, and the like. Patent Document 1 discloses a parabolic antenna device including a bowl-shaped parabolic reflector and a radiator that radiates electromagnetic waves toward the inner surface of the parabolic reflector. In the parabolic antenna device of Patent Document 1, the parabolic reflector is configured by connecting a central segment disposed at the center of the parabolic reflector with a plurality of circumferential segments arranged around the central segment. In this configuration, the plurality of circumferential segments can be positioned relative to the central segment. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-134275 Summary of the Invention [Problem to be solved by the invention]

[0004] In parabolic antenna devices, it has been considered to construct a parabolic reflector without using a central divider in order to reduce the number of parts and manufacturing costs. However, if there is no central divider, it is difficult to assemble a parabolic antenna device including a parabolic reflector.

[0005] The present invention has been made in view of the above circumstances, and has as its object to provide a parabolic antenna device that can be easily assembled even without a central divided body, and a method for manufacturing the parabolic antenna device. [Means for solving the problem]

[0006] A parabolic antenna device according to one aspect of the present invention includes a parabolic reflector having a bowl-shaped, concave reflecting surface with a through hole formed at the center of the reflecting surface; an antenna base disposed on the outer surface of the parabolic reflector and having a flat surface perpendicular to the axial direction of the through hole; and a positioning insert fixed to the antenna base, formed in a columnar shape extending in a direction perpendicular to the flat surface, and inserted into the through hole. The parabolic reflector includes a plurality of circumferentially divided bodies arranged in the circumferential direction of the parabolic reflector, each having an inner edge surface that forms a portion of the circumferential direction of the inner circumferential surface of the through hole. The positioning insert has an outer peripheral surface that faces the inner circumferential surface when inserted into the through hole. The antenna base has a holder that holds the plurality of circumferentially divided bodies.

[0007] In the parabolic antenna device having the above configuration, the multiple circumferential divisions can be positioned using the flat surface of the antenna base and the positioning insertion portion as references, making it possible to easily assemble a parabolic antenna device that does not have a central division.

[0008] In the parabolic antenna device, the outer peripheral surface of the positioning insertion portion may be in contact with at least two inner edge surfaces of the plurality of circumferential division bodies arranged in the circumferential direction.

[0009] In the above configuration, even if the axis of the through hole of the parabolic reflector is not clear due to the presence of a step between the inner edge surfaces adjacent in the circumferential direction, the axis of the positioning insertion part inserted into the through hole can be set as the axis of the through hole (i.e., the axis of the parabolic reflector), thereby making the axis of the parabolic reflector clear.

[0010] In addition, the parabolic antenna device may further include a positioning pin that is formed in the holding portion and the circumferential divided body held by the holding portion, and is inserted into the positioning holes in both the holding portion and the circumferential divided body.

[0011] In the above configuration, even after the parabolic reflector is disassembled into multiple circumferentially divided bodies, the parabolic reflector can be easily assembled without aligning the relative positions of adjacent circumferentially divided bodies by passing the same positioning pin through the positioning holes of both the holding portion and the circumferentially divided bodies.

[0012] A method for manufacturing a parabolic antenna device according to one aspect of the present invention is a method for manufacturing the parabolic antenna device, comprising: a placing step of placing the antenna base on the flat mounting surface so that the flat surface is in surface contact with the flat mounting surface; and a holding step of holding the plurality of circumferential divided bodies in the holding portion of the antenna base so that the inner edge surfaces of the plurality of circumferential divided bodies each face the outer peripheral surface of the positioning insertion portion fixed to the antenna base.

[0013] In the above method, the plurality of circumferentially divided bodies can be easily positioned using the flat surface of the antenna base and the positioning inserts as references. Also, by performing the holding step with the antenna base placed on the mounting surface so that the flat surface of the antenna base is in surface contact with the mounting surface, the plurality of circumferentially divided bodies can be stably held on the antenna base. Therefore, a parabolic antenna device that does not have a central divided body can be easily assembled.

[0014] In the manufacturing method of the parabolic antenna device, the holding process may include a jig preparation process in which a plurality of circumferential divided bodies are held in a holding portion of an antenna base so that no steps occur on the reflecting surface between adjacent circumferential divided bodies and so that no steps occur on the edge between the inner surface of the through hole and the reflecting surface between adjacent circumferential divided bodies, and a positioning jig having a contact portion that contacts the edge around the entire circumference is prepared, and after the holding process and the jig preparation process, an axis adjustment process may be carried out in which the positioning jig is inserted into the through hole from the reflecting surface side and attached to the positioning insertion portion, so that the contact portion contacts the entire circumference of the edge and the axis of the positioning insertion portion is aligned with the axis of the positioning jig, which is centered on the contact portion.

[0015] According to the above method, the axis of the positioning insertion part can be made closer to the axis of the through hole at the edge of the reflecting surface or can be made to coincide with the axis of the through hole at the edge. In other words, the axis of the positioning insertion part, which is set as the axis of the through hole (axis of the parabolic reflector), can be set with higher accuracy. This allows the axis of the parabolic reflector to be set with higher accuracy. [Effects of the Invention]

[0016] According to the present invention, a parabolic antenna device that does not have a central divided body can be easily assembled. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a side view showing a parabolic antenna device according to an embodiment of the present invention; [Figure 2] FIG. 2 is a perspective view of the parabolic reflector of FIG. 1, viewed from the reflecting surface side. [Figure 3] FIG. 2 is a perspective view of the parabolic reflector of FIG. 1 as seen from its outer surface side. [Figure 4] FIG. 4 is a perspective view showing one circumferentially divided body that constitutes the parabolic reflecting mirror of FIGS. [Figure 5] FIG. 4 is an enlarged view of region V in FIG. 3. [Figure 6] FIG. 4 is a perspective view showing an antenna base and a positioning insert to be attached to the parabolic reflector of FIGS. [Figure 7] 7 is a cross-sectional view showing a base body and a positioning insertion portion of the antenna base of FIG. 6. [Figure 8] FIG. 8 is a cross-sectional view showing the antenna base and the positioning insert of FIGS. 6 and 7 attached to a parabolic reflector. [Figure 9] 10 is a view showing a state in which the positioning insertion portion is inserted into the through-hole of the parabolic reflector, as viewed from the reflecting surface side of the parabolic reflector. FIG. [Figure 10]10 is a cross-sectional view showing the relationship between two adjacent circumferential divided bodies and a holding portion of the antenna base. FIG. [Figure 11] 10 is a cross-sectional view showing the relationship between two adjacent circumferential divided bodies and a holding portion of the antenna base. FIG. [Figure 12] 10 is a cross-sectional view illustrating an axis adjusting step in a manufacturing method for a parabolic antenna device according to an embodiment of the present invention. FIG. [Figure 13] FIG. 13 is a perspective view showing the positioning jig of FIG. [Figure 14] FIG. 10 is a perspective view showing a state before the positioning jig is attached to the parabolic reflecting mirror and the positioning insertion portion in the axis adjustment step. DETAILED DESCRIPTION OF THE INVENTION

[0018] An embodiment of the present invention will be described below with reference to Figures 1 to 14. In this embodiment, the terms "match" and "substantially match" appear, but "match" and "substantially match" are not limited to a perfect match and may also include, for example, a slight deviation. 1 to 3, a parabolic antenna device 1 according to this embodiment includes a parabolic reflector 2, an antenna base 3, and a positioning insertion portion 4. The parabolic antenna device 1 further includes a radiator 5 and a plurality of stays 6.

[0019] The parabolic reflecting mirror 2 is formed in a bowl shape. The parabolic reflecting mirror 2 is formed in a circular shape in a plan view seen from its axial direction (X-axis direction). The inner surface 11 of the parabolic reflector 2 includes a concave reflecting surface 12. The reflecting surface 12 reflects the electromagnetic waves radiated from the radiator 5. In this embodiment, the inner surface 11 of the parabolic reflecting mirror 2 is composed only of the reflecting surface 12. In other words, the parabolic reflecting mirror 2 of this embodiment is a "rimless" reflecting mirror. Note that the inner surface 11 of the parabolic reflecting mirror 2 may further include a flat edge surface that is formed, for example, on the periphery of the reflecting surface 12 and faces in the same direction as the reflecting surface 12 in the axial direction of the parabolic reflecting mirror 2. In other words, the parabolic reflecting mirror 2 may be, for example, a "rimmed" reflecting mirror.

[0020] As shown in Figures 2 and 8, a through hole 14 is formed in the center of the reflecting surface 12 of the parabolic reflecting mirror 2. The through hole 14 penetrates from the reflecting surface 12 side of the parabolic reflecting mirror 2 to the outer surface 13 side. The center of the reflecting surface 12 is the center of the parabolic reflecting mirror 2, which is circular when viewed from the axial direction. The inner peripheral surface 15 of the through hole 14 is formed in a shape that is circular when viewed from the axial direction (see Figure 9). In this embodiment, the axis A1 of the through hole 14 may be considered to be the axis A1 of the parabolic reflecting mirror 2.

[0021] As shown in Figures 2 and 3, the parabolic reflecting mirror 2 has a plurality of circumferentially divided bodies 20 (four in the illustrated example) arranged in the circumferential direction. The circumferentially divided bodies 20 are formed in a fan shape when viewed from the axial direction of the parabolic reflecting mirror 2. As shown in Figures 8 and 9, each circumferentially divided body 20 has an inner edge surface 201 that forms a part of the circumferential direction of the inner circumferential surface 15 of the through hole 14 of the parabolic reflecting mirror 2. In this embodiment, if there is no step between the inner edge surfaces 201 of adjacent circumferentially divided bodies 20, the through hole 14 of the parabolic reflecting mirror 2 will have a circular shape when viewed from the axial direction. The material forming the circumferentially divided bodies 20 may be, for example, carbon fiber reinforced plastic (CFRP).

[0022] In the parabolic reflector 2 of this embodiment, when multiple circumferential segments 20 are combined so that there is no step between the reflecting surfaces 12 of adjacent circumferential segments 20, there is a possibility that a step will occur between the inner edge surfaces 201 of adjacent circumferential segments 20 due to manufacturing errors of the multiple circumferential segments 20 (see FIG. 9). The maximum value of the step that can occur between the inner edge surfaces 201 of adjacent circumferential segments 20 may be, for example, 0.1 mm or more and 1 mm or less.

[0023] As shown in FIGS. 3 and 4, each circumferentially divided body 20 of this embodiment has a curved plate portion 21, a connecting rib 22, an outer edge rib 23, and an inner edge rib 24. The curved plate portion 21 is formed in a fan shape and constitutes part of the circumferential direction of the inner surface 11 and the outer surface 13 of the parabolic reflector 2. The connecting ribs 22 protrude from both edges of the curved plate portion 21 in the circumferential direction towards the outer surface 13 of the curved plate portion 21 and extend in the radial direction of the curved plate portion 21 along the outer surface 13 of the curved plate portion 21. The connecting ribs 22 are provided to connect circumferentially adjacent circumferential divided bodies 20 to each other by screwing or the like. By overlapping the connecting ribs 22 of two circumferentially adjacent circumferential divided bodies 20 and fixing them by screwing or the like, these two circumferential divided bodies 20 are connected to each other.

[0024] The outer edge rib 23 protrudes from the outer edge of the curved plate portion 21 in the radial direction toward the outer surface 13 of the curved plate portion 21 and extends in the circumferential direction of the curved plate portion 21 along the outer surface 13 of the curved plate portion 21. The inner edge rib 24 protrudes from the inner edge of the curved plate portion 21 in the radial direction toward the outer surface 13 of the curved plate portion 21 and extends in the circumferential direction of the curved plate portion 21 along the outer surface 13 of the curved plate portion 21. As shown in Figures 4, 8, and 9, the inner edge rib 24 forms the inner edge surface 201 of the circumferential divided body 20 described above. In this way, since each circumferential divided body 20 has the inner edge rib 24, the length of the through hole 14 of the parabolic reflector 2 in the axial direction can be made long. The connecting ribs 22, the outer edge ribs 23 and the inner edge ribs 24 described above serve to improve the rigidity of the curved plate portion 21.

[0025] As shown in Figure 1, radiator 5 radiates electromagnetic waves toward reflecting surface 12 of parabolic reflecting mirror 2. Radiator 5 is arranged at a distance from reflecting surface 12 in the axial direction of parabolic reflecting mirror 2 by a plurality of stays 6, which will be described later. Specifically, radiator 5 is located on axis A1 of parabolic reflecting mirror 2, which passes through the center of reflecting surface 12.

[0026] Each stay 6 is arranged on the inner surface 11 side of the parabolic reflector 2 and extends radially from the periphery of the parabolic reflector 2 toward the inside of the parabolic reflector 2. Specifically, each stay 6 extends axially away from the parabolic reflector 2 as it moves from the periphery of the parabolic reflector 2 toward the inside of the parabolic reflector 2. The multiple stays 6 are arranged at intervals in the circumferential direction of the parabolic reflector 2. The multiple stays 6 are connected to each other at their tip ends 6A in the extension direction. The multiple stays 6 support the radiator 5 at their tip ends 6A in the extension direction. Specifically, the radiator 5 is fixed to the tip ends 6A of the multiple stays 6.

[0027] 3, 5, and 8, the antenna base 3 is disposed on the outer surface 13 side of the parabolic reflector 2. The antenna base 3 has a flat surface 31 that is perpendicular to the axial direction of the through hole 14 of the parabolic reflector 2. The antenna base 3 has a base main body 33 that includes the flat surface 31, and a holding portion 34 that is fixed to the base main body 33 and holds the multiple circumferentially divided bodies 20. 5 and 6, the base body 33 of this embodiment is formed in a flat plate shape. One surface of the base body 33 facing the plate thickness direction of the base body 33 is a flat surface 31.

[0028] The retaining portions 34 of this embodiment retain two circumferentially adjacent circumferential segments 20. A plurality of retaining portions 34 (four in FIG. 6 ) are fixed to the other surface 32 of the base main body 33, which faces away from the flat surface 31. Each retaining portion 34 has a pair of plate portions 35 spaced apart from each other. As shown in FIGS. 5 and 10 , the pair of plate portions 35 sandwich the connecting ribs 22 of the two circumferentially overlapping circumferential segments 20. Specifically, by using fastening bolts 38 inserted through the pair of plate portions 35 and the two connecting ribs 22 sandwiched between them, the two connecting ribs 22 are sandwiched between the pair of plate portions 35. In this way, the two circumferentially adjacent segments 20 are held by the retaining portions 34. 8, the multiple circumferential divided bodies 20 held by the holding portion 34 are located on the other surface 32 side of the base main body 33. In addition, the multiple circumferential divided bodies 20 are held by the holding portion 34 with a gap between them and the other surface 32 of the base main body 33.

[0029] As shown in FIG. 10 , the diameter of the insertion hole 28 of the connecting rib 22 through which the fastening bolt 38 passes is larger than the diameter of the fastening bolt 38. Therefore, when two circumferentially aligned circumferential segments 20 are held by the holding portion 34, the two circumferentially aligned segments 20 can be moved relative to each other within a predetermined range in a direction perpendicular to the direction in which the two connecting ribs 22 are aligned (i.e., in the radial or axial direction of the parabolic reflecting mirror 2). This makes it possible to adjust the relative positions of the two circumferentially aligned segments 20 when the holding portion 34 holds the two circumferentially aligned segments 20. Therefore, the relative positions of the two circumferentially aligned segments 20 can be adjusted so that a step occurring on the reflecting surface 12 of the parabolic reflecting mirror 2 or the inner circumferential surface 15 of the through hole 14 between two circumferentially adjacent segments 20 is reduced or eliminated. As mentioned above, the circumferential divided bodies 20 are held in the holding portion 34 at a distance from the base main body 33, so that the relative positions of the two circumferential divided bodies 20 can be easily adjusted.

[0030] As shown in FIG. 11 , positioning holes 36, 26 are formed in the pair of plate portions 35 of the holding portion 34 and the connecting ribs 22 of the two circumferentially adjacent circumferential segments 20, respectively. The positioning holes 36 of the pair of plate portions 35 and the positioning holes 26 of the two connecting ribs 22 have the same diameter. The parabolic antenna device 1 of this embodiment includes a positioning pin 7 inserted into both of the positioning holes 36, 26 of the pair of plate portions 35 and the two connecting ribs 22. The diameter of the positioning pin 7 is the same as the diameter of the positioning holes 26, 36. In FIG. 11 , the positioning pin 7 is formed by a bolt, but this is not limited to this. A plurality of positioning pins 7 may be inserted into the same pair of plate portions 35 and two connecting ribs 22.

[0031] When the positioning pin 7 is inserted through both the positioning holes 26, 36 of the pair of plate portions 35 and the connecting rib 22, it is possible to suppress or prevent the two circumferential divided bodies 20 including the two connecting ribs 22 from moving relatively in a direction perpendicular to the arrangement direction of these bodies (i.e., in the radial or axial direction of the parabolic reflecting mirror 2). In other words, it is possible to position the two circumferential divided bodies 20 adjacent to each other in the circumferential direction relative to each other.

[0032] As shown in Figures 6 to 8, the positioning insert 4 is fixed to the antenna base 3 and is formed in a columnar shape extending in a direction (X-axis direction) perpendicular to the flat surface 31 of the antenna base 3. The positioning insert 4 is inserted into the through hole 14 of the parabolic reflector 2. The positioning insert 4 inserted into the through hole 14 does not protrude toward the reflecting surface 12 of the parabolic reflector 2. The positioning insert 4 has an outer peripheral surface 41 that faces the inner peripheral surface 15 of the through hole 14 when inserted into the through hole 14. The shape of the positioning insert 4 as viewed from the axial direction corresponds to the shape of the through hole 14 as viewed from the axial direction. In this embodiment, the positioning insert 4 is formed in a circular shape as viewed from the axial direction (see Figures 6 and 9).

[0033] 9, the positioning insert 4 of this embodiment is formed so that its outer circumferential surface 41 contacts at least two of the inner edge surfaces 201 of the multiple circumferentially divided bodies 20 arranged in the circumferential direction. The outer circumferential surface 41 of the positioning insert 4 may contact three or more inner edge surfaces 201, or may contact all of the inner edge surfaces 201. In FIG. 9, the outer circumferential surface 41 of the positioning insert 4 contacts two inner edge surfaces 201 that are not adjacent in the circumferential direction, but it may also contact, for example, two inner edge surfaces 201 that are adjacent in the circumferential direction.

[0034] Furthermore, the diameter dimension of the positioning insertion portion 4 as viewed in the axial direction is set so that a gap is formed between the outer peripheral surface 41 of the positioning insertion portion 4 inserted into the through hole 14 and the inner peripheral surface 15 of the through hole 14. The size of the gap formed between the outer peripheral surface 41 of the positioning insertion portion 4 and the inner peripheral surface 15 of the through hole 14 is set according to a step (e.g., 0.1 mm to 1 mm) that occurs on the inner peripheral surface 15 of the through hole 14 in the circumferential direction. This allows the positioning insertion portion 4 to be inserted into the through hole 14 even if there is a step on the inner peripheral surface 15 of the through hole 14.

[0035] When the positioning insertion part 4 is inserted into the through hole 14, if there is a gap between the outer peripheral surface 41 of the positioning insertion part 4 and the inner peripheral surface 15 of the through hole 14, the axis A2 of the positioning insertion part 4 and the axis A1 of the through hole 14 may be tilted relative to each other. In response to this, by setting the lengths of the through hole 14 and the positioning insertion part 4 in the axial direction to be long, the tilt angle between the axis A2 of the positioning insertion part 4 and the axis A1 of the through hole 14 can be kept small. The lengths of the through hole 14 and the positioning insertion part 4 may be set so that the tilt angle is within 1 degree, for example.

[0036] As shown in FIG. 7 , the positioning insert 4 of this embodiment has a flange 42 that protrudes from the outer peripheral surface 41 at one end (base end) in the axial direction. The positioning insert 4 is inserted into the base body 33 from the flat surface 31 side (one surface side), and is positioned relative to the base body 33 when the flange 42 comes into contact with the flat surface 31. The positioning insert 4 is fixed to the base body 33 by screwing the flange 42 to the base body 33. Note that the positioning insert 4 may also be positioned relative to the base body 33 by, for example, inserting it into the base body 33 from the other surface 32 side of the base body 33. Any method may be used to fix the positioning insert 4 to the base body 33.

[0037] Furthermore, the positioning insertion portion 4 of this embodiment is formed with an insertion hole 43 recessed in the axial direction from the tip of the positioning insertion portion 4 extending from the base body 33. The insertion hole 43 is formed in order to attach a positioning jig 100 (see FIGS. 12 to 14) to the positioning insertion portion 4 in a manufacturing method of the parabolic antenna device 1, which will be described later. Although the insertion hole 43 in the illustrated example penetrates the positioning insertion portion 4 in the axial direction, it does not have to penetrate therethrough, for example.

[0038] Next, an example of a method for manufacturing the parabolic antenna device 1 according to this embodiment will be described. When manufacturing the parabolic antenna of this embodiment shown in Figures 1 to 11, a reflector assembly process is first carried out in which a plurality of circumferential segments 20 are connected to assemble the parabolic reflector 2. In the reflector assembly process, the connecting ribs 22 of two circumferentially adjacent segments 20 are screwed together so that the connecting ribs 22 are held in an overlapping state. The assembly of the parabolic reflector 2 at this stage is a temporary assembly that allows the adjacent circumferential segments 20 to move slightly relative to each other. Furthermore, as shown in Figures 6 and 7, the holding portion 34 is attached to the base main body 33 in advance to assemble the antenna base 3, and then an antenna base assembly process is carried out in which the positioning insertion portion 4 is attached to the antenna base 3. The order of the reflector assembly process and the antenna base assembly process does not particularly matter.

[0039] Next, as shown in Figures 6 and 12, a placement process is carried out in which the antenna base 3 is placed on a flat placement surface G (for example, the ground or a floor). In the placement process, the flat surface 31 of the antenna base 3 is brought into surface contact with the placement surface G. This allows the antenna base 3 and the positioning insertion part 4 to be stably positioned. When the antenna base 3 is placed on the placement surface G, the positioning insertion part 4 extends upward from the placement surface G. Furthermore, the axis A2 of the positioning insertion part 4 is perpendicular or nearly perpendicular to the placement surface G.

[0040] After the placing process, a holding process is carried out in which the multiple circumferential divided bodies 20 are held by the holding portions 34 of the antenna base 3. In the holding process, the inner edge surfaces 201 of the multiple circumferential divided bodies 20 are made to face the outer peripheral surfaces 41 of the positioning insertion portions 4 fixed to the antenna base 3. In this embodiment, before the holding step, the parabolic reflector 2 is assembled by connecting the multiple circumferential division bodies 20. Therefore, in the holding step, the positioning insertion parts 4 are inserted into the through holes 14 from the outer surface 13 side of the parabolic reflector 2, so that the inner edge surfaces 201 of the multiple circumferential division bodies 20 face the outer peripheral surfaces 41 of the positioning insertion parts 4 fixed to the antenna base 3.

[0041] 10 , in the holding step of this embodiment, fastening bolts 38 are used to sandwich the connecting ribs 22 of two circumferentially overlapping circumferentially divided bodies 20 between a pair of plate portions 35 of the holding portion 34. Here, the diameter of the insertion hole 28 of the connecting rib 22 through which the fastening bolt 38 passes is larger than the diameter of the fastening bolt 38. Therefore, with the two connecting ribs 22 sandwiched between the pair of plate portions 35, the two circumferentially divided bodies 20 can be moved relatively within a predetermined range in a direction perpendicular to the direction in which the two connecting ribs 22 are aligned (i.e., in the radial direction or axial direction of the parabolic reflecting mirror 2).

[0042] In the holding step, after sandwiching the two connecting ribs 22 between the pair of plate portions 35, the relative positions of the two circumferentially adjacent circumferential segments 20 are adjusted to hold the two circumferentially adjacent circumferential segments 20 so that no step is created on the reflecting surface 12 of the parabolic reflector 2 between the two circumferentially adjacent circumferential segments 20. Furthermore, the relative positions of the two circumferentially adjacent circumferential segments 20 are adjusted to hold the two circumferentially adjacent circumferential segments 20 so that no step is created on the edge 17 (see FIG. 14 ) between the inner circumferential surface 15 of the through hole 14 and the reflecting surface 12 between the two circumferentially adjacent circumferential segments 20. In the above-described position adjustment of the two circumferentially adjacent circumferential segments 20, it is acceptable for a step to be created on the inner circumferential surface 15 of the through hole 14 at a portion of the inner circumferential surface 15 of the through hole 14 that is distant from the reflecting surface 12 in the axial direction of the through hole 14.

[0043] In the state after the holding process described above, the inner edge surfaces 201 of all of the circumferential divided bodies 20 may be in contact with the outer peripheral surface 41 of the positioning insert portion 4, or only the inner edge surfaces 201 of some of the circumferential divided bodies 20 may be in contact with the outer peripheral surface 41 of the positioning insert portion 4. Also, the inner edge surfaces 201 of all of the circumferential divided bodies 20 do not have to be in contact with the outer peripheral surface 41 of the insert portion.

[0044] The manufacturing method of this embodiment further includes a jig preparation step of preparing a positioning jig 100 shown in Figures 12 to 14. The positioning jig 100 has a contact portion 101 that contacts an edge 17 between the inner peripheral surface 15 of the through hole 14 and the reflecting surface 12 over the entire circumference. The positioning jig 100 also has an insertion protrusion 102 that is inserted into the insertion hole 43 of the positioning insertion portion 4. In the positioning jig 100, the axis A3 of the contact portion 101 and the insertion protrusion 102 coincide. In the following description, the axis A3 of the contact portion 101 and the insertion protrusion 102 will be referred to as the axis A3 of the positioning jig 100.

[0045] The size and shape of the insertion protrusion 102 as viewed from the axial direction correspond to the insertion hole 43 of the positioning insertion portion 4. Therefore, when the insertion protrusion 102 is inserted into the insertion hole 43 of the positioning insertion portion 4, the axis A3 of the positioning jig 100 substantially coincides with the axis A2 of the positioning insertion portion 4. The relative order of the jig preparation step and the steps such as the placement step and holding step is not particularly important.

[0046] After the jig preparation step and the holding step, an axis adjustment step is carried out. In the axis adjustment step, as shown in Figures 12 and 14, the positioning jig 100 is inserted into the through-hole 14 from the reflecting surface 12 side of the parabolic reflecting mirror 2 and attached to the positioning insertion part 4. Then, the contact part 101 of the positioning jig 100 is brought into contact with the entire circumference of the edge 17. Furthermore, the insertion protrusion 102 of the positioning jig 100 is inserted into the insertion hole 43 of the positioning insertion part 4. As a result, the axis A2 of the positioning insertion part 4 approximately coincides with the axis A3 of the positioning jig 100.

[0047] In the axis adjustment step, the contact portion 101 of the positioning jig 100 comes into contact with the entire circumference of the edge 17, thereby making it possible to align the axis A3 of the positioning jig 100 with the axis A1 of the through hole 14 in the edge 17. Furthermore, the insertion protrusion 102 of the positioning jig 100 is inserted into the insertion hole 43 of the positioning insertion portion 4, making it possible to align the axis A2 of the positioning insertion portion 4 with the axis A3 of the positioning jig 100. This makes it possible to align the axis A2 of the positioning insertion portion 4 with the axis A1 of the through hole 14 (i.e., the axis A1 of the parabolic reflecting mirror 2).

[0048] After the above-described axis adjustment step, the relative positioning of the parabolic reflector 2, the antenna base 3, and the positioning insertion portion 4 has been completed. Therefore, after the axis adjustment step, for example, as shown in FIG. 11 , a pin insertion step may be carried out in which positioning pins 7 are inserted into positioning holes 26, 36 of a pair of plate portions 35 (holding portions 34) and two connecting ribs 22 (circumferentially divided bodies 20) sandwiched therebetween. This makes it possible to maintain the relative positions of the parabolic reflector 2, the antenna base 3, and the positioning insertion portion 4. Note that in the pin insertion step, positioning holes 26, 36 may be newly formed in the pair of plate portions 35 and the connecting ribs 22, and then the positioning pins 7 may be inserted into these positioning holes 26, 36. After the pin insertion step, the positioning jig 100 used in the axis adjustment step may be removed.

[0049] Finally, the manufacturing method of the parabolic antenna device 1 is completed by carrying out a radiator mounting process in which multiple stays 6 and radiators 5 shown in Figure 1 are mounted on the parabolic reflector 2. In the radiator mounting process, the radiator 5 may be positioned on the axis A1 of the parabolic reflector 2 using the positioning insertion part 4 inserted into the through hole 14 of the parabolic reflector 2. In addition, the positioning of the radiator 5 may be performed using, for example, the "radiator positioning jig" described in Patent Document 1.

[0050] In the above-described manufacturing method of the parabolic antenna device 1, if the axis adjustment step is not performed (the positioning jig 100 is not used), when adjusting the positions of circumferentially adjacent circumferential divided bodies 20 in the holding step, it may be acceptable for a step to occur in the edge 17 between two circumferentially adjacent circumferential divided bodies 20. Instead, for example, the position adjustment of adjacent circumferential divided bodies 20 may be performed so that the outer peripheral surface 41 of the positioning insertion portion 4 contacts two or more inner edge surfaces 201 of the inner edge surfaces 201 of the multiple circumferentially aligned circumferential divided bodies 20.

[0051] In the manufacturing method of the parabolic antenna device 1 described above, for example, the reflector assembly process may not be performed, and the parabolic reflector 2 may be assembled by holding multiple circumferentially divided bodies 20 in the holding portion 34 in the holding process.

[0052] The parabolic antenna device 1 of this embodiment manufactured as described above is, for example, a weather radar, and may further include a rotating base 9 on which the parabolic reflector 2 is attached, as illustrated in Fig. 1. The rotating base 9 rotates the parabolic reflector 2 about a vertical axis A4 (an axis extending up and down in Fig. 1) extending vertically and a horizontal axis A5 (an axis extending perpendicular to the plane of the paper in Fig. 1). This allows the parabolic reflector 2 to be oriented in various directions by the rotating base 9. The parabolic antenna device 1 of this embodiment is attached to the rotary table 9 with the flat surface 31 of the antenna base 3 facing the rotary table 9 as a reference.

[0053] As described above, the parabolic antenna device 1 of this embodiment includes the parabolic reflector 2, which is bowl-shaped and has a concave reflecting surface 12 with a through hole 14 formed at the center of the reflecting surface 12; the antenna base 3, which is disposed on the outer surface 13 of the parabolic reflector 2 and has a flat surface 31 perpendicular to the axial direction of the through hole 14; and the positioning insert 4, which is fixed to the antenna base 3, has a columnar shape extending in a direction perpendicular to the flat surface 31, and is inserted into the through hole 14. The parabolic reflector 2 includes a plurality of circumferentially arranged divided bodies 20, each having an inner edge surface 201 that forms a portion of the circumferential direction of the inner circumferential surface 15 of the through hole 14. The positioning insert 4 has an outer circumferential surface 41 that faces the inner circumferential surface 15 when inserted into the through hole 14. The antenna base 3 includes a holder 34 that holds the plurality of circumferentially divided bodies 20.

[0054] This allows the multiple circumferential divided bodies 20 to be positioned using the flat surface 31 of the antenna base 3 and the positioning insertion portion 4 as references. Specifically, the multiple circumferential divided bodies 20 can be easily positioned by holding the circumferential divided bodies 20 in the holding portion 34 of the antenna base 3 with the inner edge surface 201 of each circumferential divided body 20 facing the outer circumferential surface 41 of the positioning insertion portion 4. Therefore, the parabolic antenna device 1 that does not have a central divided body can be easily assembled.

[0055] Furthermore, in the parabolic antenna device 1 of this embodiment, the outer peripheral surface 41 of the positioning insertion portion 4 comes into contact with at least two of the inner peripheral surfaces 201 of the multiple circumferentially divided bodies 20 arranged in the circumferential direction. Therefore, even if the axis A1 of the through hole 14 of the parabolic reflector 2 is not clear due to a step between the inner peripheral surfaces 201 adjacent in the circumferential direction, the axis A2 of the positioning insertion portion 4 inserted into the through hole 14 can be set as the axis A1 of the through hole 14 (i.e., the axis A1 of the parabolic reflector 2). This makes it possible to clarify the axis A1 of the parabolic reflector 2.

[0056] Since the axis A1 of the parabolic reflector 2 is clearly defined, it becomes possible to use the positioning insert 4 to accurately position the radiator 5 on the axis A1 of the parabolic reflector 2. Furthermore, by clarifying the axis A1 of the parabolic reflector 2, when the parabolic reflector 2 is attached to the rotating table 9 using the flat surface 31 of the antenna base 3, the axis A1 of the parabolic reflector 2 can be made to intersect with the rotation axis (vertical axis A4, horizontal axis A5) of the rotating table 9 with certainty. In other words, it is possible to prevent the axis A1 of the parabolic reflector 2 from being misaligned with the rotation axis of the rotating table 9. This makes it possible to accurately grasp the orientation of the parabolic reflector 2 when it is rotated by the rotating table 9.

[0057] Furthermore, in the parabolic antenna device 1 of this embodiment, positioning holes 36, 26 are formed in the holding portion 34 and the circumferential divided body 20, and a positioning pin 7 is inserted through the positioning holes 36, 26 of both the holding portion 34 and the circumferential divided body 20. As a result, even after the parabolic reflector 2 has been disassembled into a plurality of circumferential divided bodies 20, by passing the same positioning pin 7 through the positioning holes 26, 36 of both the holding portion 34 and the circumferential divided body 20, the parabolic reflector 2 can be easily assembled without having to align the relative positions of circumferentially adjacent circumferential divided bodies 20.

[0058] Furthermore, in the manufacturing method of the parabolic antenna device 1 of this embodiment, the plurality of circumferential divided bodies 20 are held by the holding portions 34 in a state in which the antenna base 3 is placed on the mounting surface G so that the flat surface 31 of the antenna base 3 is in surface contact with the mounting surface G. This allows the plurality of circumferential divided bodies 20 to be stably held on the antenna base 3. Furthermore, in the holding step, after the antenna base 3 is placed as described above, the plurality of circumferential divided bodies 20 are held by the holding portions 34 of the antenna base 3 so that the inner edge surfaces 201 of the plurality of circumferential divided bodies 20 face the outer circumferential surfaces 41 of the positioning insertion portions 4 fixed to the antenna base 3. This allows the plurality of circumferential divided bodies 20 to be easily positioned using the flat surface 31 of the antenna base 3 and the positioning insertion portions 4 as references. Therefore, the parabolic antenna device 1 can be easily assembled.

[0059] Furthermore, in the manufacturing method of the parabolic antenna device 1 of this embodiment, in the holding step, the multiple circumferentially divided bodies 20 are held by the holding portion 34 of the antenna base 3 so that no steps are created on the reflecting surface 12 between circumferentially adjacent circumferentially divided bodies 20 and no steps are created on the edge 17 between the inner circumferential surface 15 of the through hole 14 and the reflecting surface 12 between circumferentially adjacent circumferentially divided bodies 20. Furthermore, in the axis adjustment step after the holding step, the positioning jig 100 is inserted into the through hole 14 from the reflecting surface 12 side and attached to the positioning insertion portion 4, and the contact portion 101 of the positioning jig 100 is brought into contact with the entire circumference of the edge 17, and the axis A2 of the positioning insertion portion 4 is aligned with the axis A3 of the positioning jig 100, which is centered on the contact portion 101. Therefore, in the axis adjustment step, the axis A2 of the positioning insertion part 4 can be brought closer to the axis A1 of the through hole 14 in the edge 17, or can be made to coincide with the axis A1 of the through hole 14 in the edge 17. In other words, the axis A2 of the positioning insertion part 4, which is set as the axis A1 of the through hole 14 (axis A1 of the parabolic reflecting mirror 2), can be set with higher accuracy. This allows the axis A1 of the parabolic reflecting mirror 2 to be set with higher accuracy.

[0060] Although the present invention has been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. [Explanation of symbols]

[0061] 1 Parabolic antenna device 2 Parabolic reflector 3 Antenna base 4 Positioning insertion part 7 Locating Pins 12 Reflective surface 13 Exterior 14 Through holes 15 Inner surface 20 Circumferential division body 201 Inner edge surface 26 Positioning hole 31 Flat surface 34 Holding part 36 Positioning hole 41 Outer surface 100 Positioning jig 101 Contact part G Placement surface

Claims

1. a parabolic reflector formed in a bowl shape and having a concave reflecting surface, with a through hole formed in the center of the reflecting surface; an antenna base disposed on an outer surface side of the parabolic reflector and having a flat surface perpendicular to the axial direction of the through hole; a positioning insertion portion that is fixed to the antenna base, is formed in a columnar shape extending in a direction perpendicular to the flat surface, and is inserted into the through hole; the parabolic reflector includes a plurality of circumferentially divided bodies arranged in a circumferential direction of the parabolic reflector, each having an inner edge surface that constitutes a part of the circumferential direction of the inner circumferential surface of the through hole, the positioning insertion portion has an outer circumferential surface that faces the inner circumferential surface when inserted into the through hole, The antenna base includes a holding portion that holds the plurality of circumferentially divided bodies.

2. 2. The parabolic antenna device according to claim 1, wherein the outer peripheral surface of the positioning insertion portion is in contact with inner edge surfaces of at least two of the inner edge surfaces of the plurality of circumferentially arranged divided bodies.

3. a positioning hole is formed in the holding portion and the circumferential divided body held by the holding portion; The parabolic antenna device according to claim 1 or 2, further comprising a positioning pin inserted into the positioning holes of both the holding portion and the circumferentially divided body.

4. A method for manufacturing the parabolic antenna device according to claim 1 or 2, comprising: a placing step of placing the antenna base on a flat placing surface so that the flat surface is in surface contact with the flat placing surface; A method for manufacturing a parabolic antenna device, comprising: a holding process for holding a plurality of circumferentially divided bodies in the holding portion of the antenna base so that the inner edge surfaces of the plurality of circumferentially divided bodies each face the outer peripheral surface of the positioning insertion portion fixed to the antenna base.

5. In the holding step, the plurality of circumferentially divided bodies are held by a holding portion of the antenna base so that no step is generated on the reflecting surface between the circumferentially adjacent circumferentially divided bodies and no step is generated on an edge between the inner circumferential surface of the through hole and the reflecting surface between the circumferentially adjacent circumferentially divided bodies, a jig preparation step of preparing a positioning jig having a contact portion that contacts the edge over the entire periphery; A method for manufacturing a parabolic antenna device as described in claim 4, wherein after the holding process and the jig preparation process, the positioning jig is inserted into the through hole from the reflecting surface side and attached to the positioning insertion portion, thereby bringing the contact portion into contact with the entire circumference of the edge and aligning the axis of the positioning insertion portion with the axis of the positioning jig centered on the contact portion.

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