Rotary joint

Abstract

This rotary joint is provided with: a stationary body which is disposed along an arc centered on a central axis and has a first split waveguide having a flat opening surface on one surface, a first waveguide having one end connected to one end of the first split waveguide via a first coupling part, and a second waveguide having one end connected to the other end of the first split waveguide via a second coupling part; and a rotating body that is disposed about the central axis along a circumference having the same diameter as the arc in which the first split waveguide is disposed, and that has an annular second split waveguide having a flat opening surface on one surface facing the opening surface of the first split waveguide. And a plurality of third waveguides which are disposed on the other surface of the second divided waveguide, which faces the one surface of the second divided waveguide, are spaced apart from each other, and are coupled to the second divided waveguide via directional couplers, the third waveguides being rotatable about the central axis with respect to the stationary body, and the third waveguides being disposed at positions where the opening surfaces of the third waveguides face each other. The second split waveguide and the first split waveguide constitute a waveguide.

Description

Technical Field

[0001] The present invention relates to a rotary joint having a stationary body and a rotating body and used for transmitting electromagnetic waves. Background Art

[0002] In a microwave communication system, Non-Patent Document 1 shows a rotary joint that forms a link between a fixed portion and a movable portion.

[0003] The rotary joint shown in non-patent document 1 is composed of three planar waveguide rings of the same diameter stacked on a coaxial axis, and the center ring is divided into two halves along the plane. The upper half of the center ring is brazed to the output ring, and the lower half is brazed to the input ring, and power is transmitted from the input ring to the output ring via the center ring.

[0004] Non-patent document 1: K.Rambabu and Jens Bornemann., "Compact Single-ChannelRotary Joint Using Ridged Waveguide Sections for Phase Adjustment" IEEETRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, VOL.51, NO.8, AUGUST.2003, pp.1982-1986 Summary of the invention

[0005] The rotary joint shown in Non-Patent Document 1 transmits power from the input ring to the output ring via the ring resonance mode of the center ring. Therefore, it operates only within the frequency range of the ring resonance of the center ring. The operating frequency band is narrow and there are problems in widening the frequency band.

[0006] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to obtain a rotary joint having a wide-band transmission characteristic.

[0007] The rotary joint involved in the present invention comprises: a stationary body, which is arranged along an arc with a central axis as the center, and has a first split waveguide having a flat opening surface on one side, a first waveguide whose one end is connected to one end of the first split waveguide via a first coupling portion, and a second waveguide whose one end is connected to the other end of the first split waveguide via a second coupling portion; and a rotating body, which is arranged along a circumference of the same diameter as the arc with the first split waveguide arranged as the center, and has an annular second split waveguide having a flat opening surface on one side opposite to the opening surface of the first split waveguide, and a plurality of third waveguides each arranged at a distance from each other on the other side of the second split waveguide opposite to the one side, and each connected to the second split waveguide via a directional coupler, the rotating body is freely rotatable relative to the stationary body with the central axis as the center, and the second split waveguide and the first split waveguide constitute a waveguide at the position where their opening surfaces face each other.

[0008] Effects of the Invention

[0009] According to the present invention, a rotary joint has a wide-band transmission characteristic. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 This is a schematic perspective view showing the rotary joint according to the first embodiment.

[0011] Figure 2 The stationary body in the rotary joint according to the first embodiment Figure 1 A11-A11 section view in.

[0012] Figure 3 The stationary body in the rotary joint according to the first embodiment Figure 1 A12-A12 section view in.

[0013] Figure 4 The stationary body in the rotary joint according to the first embodiment Figure 3 A13-A13 section view in.

[0014] Figure 5 The rotating body in the rotary joint according to the first embodiment Figure 1 A21-A21 section view in.

[0015] Figure 6 The rotating body in the rotary joint according to the first embodiment Figure 1 A22-A22 section view in.

[0016] Figure 7 The rotating body in the rotary joint according to the first embodiment Figure 6 A23-A23 section view in.

[0017] Figure 8 This is a diagram for explaining the operating principle of the rotary joint according to the first embodiment.

[0018] Fig. 9 This is a diagram for explaining the conveying path in Example 1 of the first position in the rotary joint according to the first embodiment.

[0019] Fig.10 This is a diagram for explaining the transmission path in Example 1 of the second position in the rotary joint according to the first embodiment.

[0020] Fig.11 This is a schematic perspective view showing a rotary joint according to the second embodiment.

[0021] Fig.12 The rotary body in the rotary joint according to the second embodiment Fig.11 A21-A21 section view in.

[0022] Fig.13 The rotary body in the rotary joint according to the second embodiment Fig.12 A23-A23 section view in.

[0023] Fig.14 This is a diagram for explaining the transmission path in Example 1 of the first position in the rotary joint according to the second embodiment.

[0024] Fig.15 This is a diagram for explaining the transmission path in Example 1 of the second position in the rotary joint according to the first embodiment. DETAILED DESCRIPTION

[0025] Implementation method 1.

[0026] according to Figures 1 to 10 The rotary joint according to the first embodiment will be described.

[0027] The rotary joint involved in the first embodiment is as follows Figure 1 As shown, there are a stationary body 10 and a rotating body 20 .

[0028] The stationary body 10 is an input-side transmission body that transmits a transmission signal from the transmission circuit 30 .

[0029] The rotating body 20 is an output-side transmission body that receives the transmission signal transmitted from the stationary body 10 and transmits the signal to the receiving circuits 41 and 42 .

[0030] The transmission signal is an electromagnetic wave signal generated by microwaves or light, and is hereinafter referred to as a transmission signal.

[0031] The rotating body 20 is disposed opposite to the stationary body 10 with the central axis O being coaxial therewith, and is rotatable about the central axis O.

[0032] The rotating body 20 can rotate relative to the stationary body 10 via a ball bearing (not shown) interposed in a gap between surfaces facing the stationary body 10 in the direction of the central axis O.

[0033] Furthermore, the stationary body 10 is used as the input-side conveying body and the rotating body 20 is used as the output-side conveying body. However, the stationary body 10 may be used as the output-side conveying body and the rotating body 20 may be used as the input-side conveying body.

[0034] In addition, the relationship between the stationary body 10 and the rotating body 20 only needs to be relative to each other, so both the stationary body 10 and the rotating body 20 can rotate, and for convenience, the stationary body 10 will be described.

[0035] Stationary body 10 Figure 1 and Figure 4 As shown, it includes a first split waveguide 11 , a first connecting portion 12A, a second connecting portion 12B, a first waveguide 13 , and a second waveguide 14 .

[0036] The first split waveguide 11 , the first connecting portion 12A, the second connecting portion 12B, the first waveguide 13 , and the second waveguide 14 form an annular shape centered on the central axis O, with the other end of the first waveguide 13 and the other end of the second waveguide 14 facing each other.

[0037] That is, the first waveguide 13 , the first coupling portion 12A, the first segmented waveguide 11 , the second coupling portion 12B, and the second waveguide 14 are arranged in a ring shape in one direction, in the clockwise direction in the first embodiment, in this order.

[0038] In the following description, the position direction is assumed to be the clockwise direction.

[0039] In Embodiment 1, a surface of stationary body 10 that is orthogonal to central axis O and faces rotating body 20 is referred to as one surface, a surface located opposite to one surface is referred to as another surface, a surface located on the inner periphery is referred to as an inner peripheral surface, and a surface located on the outer periphery is referred to as an outer peripheral surface.

[0040] The first division waveguide 11 is arranged along an arc centered on the central axis O, and has a flat opening surface 11A on one surface.

[0041] The cross-sectional shape of the first segmented waveguide 11 is as follows: Figure 2 As shown, it has a shape having three sides of a rectangle excluding the opening surface 11A.

[0042] That is, the first division waveguide 11 is formed of an arc-shaped metallic conductor having the other surface wall, the inner peripheral wall, and the outer peripheral wall.

[0043] The cross-sectional shape here refers to a cross-sectional shape in the direction along the central axis O, in other words, a cross-sectional shape on a plane passing through the central axis O and parallel to the central axis O.

[0044] In the following description, the cross-sectional shape of a waveguide tube and the cross-sectional shape of a waveguide also refer to the cross-sectional shape in the direction along the central axis O.

[0045] One end of the first waveguide 13 is connected to one end of the first division waveguide 11 via the first coupling portion 12A, and the other end is connected to a transmission circuit 30 that outputs a transmission signal.

[0046] The cross-sectional shape of the first waveguide 13 is as follows: Figure 3 As shown, it is a rectangle.

[0047] The first waveguide 13 is arranged along an arc centered on the central axis O, and is formed of an arc-shaped metallic conductor having one surface wall, another surface wall, an inner peripheral wall, and an outer peripheral wall.

[0048] The first waveguide 13 is cylindrical, and the interior thereof serves as a waveguide.

[0049] The cross-sectional shape of the waveguide in the first waveguide tube 13 is also a rectangle in which the length of the side a in the direction of the central axis O, that is, the side a parallel to the central axis O, is longer than the length of the side perpendicular to the central axis O.

[0050] The length of the side a in the direction of the central axis O in the cross-sectional shape of the waveguide in the first waveguide 13 is longer than half the wavelength of the wavelength of the transmission signal in the tube.

[0051] Furthermore, the first waveguide 13 has a shape along an arc centered on the central axis O, but may also be a straight line.

[0052] One end of the second waveguide 14 is connected to the other end of the first division waveguide 11 via the second coupling portion 12B, and the other end is connected to the terminal resistor 50 .

[0053] The other end of the second waveguide 14 may not be connected to the terminal resistor 50 but may be short-circuited.

[0054] The cross-sectional shape of the second waveguide 14 is a rectangle having the same size as that of the first waveguide 13 .

[0055] The second waveguide 14 is arranged along an arc centered on the central axis O, and is formed of an arc-shaped metallic cylindrical conductor having one surface wall, another surface wall, an inner peripheral wall, and an outer peripheral wall.

[0056] Furthermore, the second waveguide 14 has a shape along an arc centered on the central axis O, but may also be a straight line.

[0057] When the first split waveguide 11 is combined with the first waveguide 13 and the second waveguide 14 via the first combining portion 12A and the second combining portion 12B respectively, the other surface of the first split waveguide 11 is on the same plane as the other surface of the first waveguide 13 and the other surface of the second waveguide 14, and the opening surface of the first split waveguide 11 is on a plane that is shortened by the thickness of one surface wall of the first waveguide 13 compared with one surface of the first waveguide 13 and one surface of the second waveguide 14, or is on the same plane as one surface of the first waveguide 13 and one surface of the second waveguide 14.

[0058] The length of side b in the direction of the central axis O in the cross-sectional shape of the waveguide in the first divided waveguide tube 11, that is, the length of side b parallel to the central axis O, is 1 / 2 of the length of side a in the direction of the central axis O in the cross-sectional shape of the waveguide in the first waveguide tube 13.

[0059] In addition, 1 / 2 does not strictly mean 1 / 2, but 1 / 2 within the range allowed in design.

[0060] The thickness of the other wall in the first divided waveguide 11 is thicker than the thickness of the other wall in the first waveguide 13 , and the thickness of the inner and outer walls in the first divided waveguide 11 are the same as the thickness of the inner and outer walls in the first waveguide 13 .

[0061] Rotating body 20 Figure 1 and Figure 7 As shown, there is a second division waveguide 21 and a plurality of third waveguides 23A and 23B.

[0062] In the first embodiment, the surface of the rotating body 20 that is orthogonal to the central axis O and faces the stationary body 10 is called one surface, the surface located on the opposite side of the one surface is called the other surface, the surface located on the inner periphery is called the inner peripheral surface, and the surface located on the outer periphery is called the outer peripheral surface.

[0063] The second split waveguide 21 is as follows Figure 1 and Figure 7 As shown, it is arranged along a circle having the same diameter as the arc of the first split waveguide tube 11 centered on the central axis O, and has a flat opening surface 21A on one side that is opposite to the opening surface 11A of the first split waveguide tube 11, one side of the first waveguide tube 13 and one side of the second waveguide tube 14.

[0064] The cross-sectional shape of the second segmented waveguide 21 is as follows: Figure 5 As shown, it has a shape having three sides of a rectangle except for the opening surface 21A.

[0065] That is, the second division waveguide 21 is formed by a ring-shaped metallic conductor having the other surface wall, the inner peripheral wall, and the outer peripheral wall connected around one circumference.

[0066] The first division waveguide 11 and the second division waveguide 21 constitute a waveguide at a position where an opening surface 11A of the first division waveguide 11 and an opening surface 21A of the second division waveguide 21 face each other.

[0067] At a position where the opening surface 11A of the first divided waveguide tube and the opening surface 21A of the second divided waveguide tube 21 are opposite to each other, a choke structure is used to arrange the end surface of the outer wall of the first divided waveguide tube 11 and the end surface of the outer wall of the second divided waveguide tube 21, and the end surface of the inner wall of the first divided waveguide tube 11 and the end surface of the inner wall of the second divided waveguide tube 21 in close proximity, so that the electromagnetic field generated by the electromagnetic wave serving as the transmission signal will not leak.

[0068] In addition, the configuration may be performed in a state where the end face of the outer wall of the first divided waveguide tube 11 and the end face of the outer wall of the second divided waveguide tube 21, and the end face of the inner wall of the first divided waveguide tube 11 and the end face of the inner wall of the second divided waveguide tube 21 are in direct contact and electrically conductive.

[0069] The length of side c in the direction of the central axis O in the cross-sectional shape of the waveguide in the second divided waveguide tube 21, i.e., the side c parallel to the central axis O, is the same as the length of side b in the direction of the central axis O in the cross-sectional shape of the waveguide in the first divided waveguide tube 11.

[0070] That is, the cross-sectional shape of the waveguide in the waveguide tube formed by the first divided waveguide tube 11 and the second divided waveguide tube 21 is rectangular, and the side (b+c) in the cross-sectional shape of the waveguide in the direction of the central axis O is longer than the length of the side perpendicular to the central axis O, and is longer than 1 / 2 wavelength of the wavelength of the transmitted signal in the tube.

[0071] Furthermore, although the lengths of side b and side c are set to be the same, if the length of side (b+c) is longer than 1 / 2 wavelength of the wavelength of the transmission signal in the tube, the lengths of side b and side c can be set to different lengths.

[0072] However, the length of the side c is less than or equal to 1 / 2 wavelength of the wavelength of the transmission signal in the tube.

[0073] The second division waveguide 21 and the first waveguide 13 form a dummy waveguide at a position where an opening surface 21A of the second division waveguide 21 and a surface of the first waveguide 13 face each other.

[0074] The length of the side c in the direction of the central axis O in the cross-sectional shape of the pseudo waveguide formed by the second divided waveguide tube 21 and the first waveguide tube 13 is the same as the length of the side c in the direction of the central axis O in the cross-sectional shape of the waveguide in the second divided waveguide tube 21, and is less than or equal to 1 / 2 wavelength of the wavelength of the signal transmitted in the tube.

[0075] Therefore, the transmission signal is not transmitted to the dummy waveguide formed at the position where the opening surface 21A of the second division waveguide 21 and the one surface of the first waveguide 13 face each other.

[0076] When the first waveguide 13 is formed into a straight line, a dummy waveguide is formed at a position where one surface of the first waveguide 13 faces the opening surface 21A of the second split waveguide 21 at one end connected to the first coupling portion 12A.

[0077] The second division waveguide 21 and the second waveguide 14 constitute a dummy waveguide at a position where an opening surface 21A of the second division waveguide 21 and a surface of the second waveguide 14 face each other.

[0078] The length of the side c in the direction of the central axis O in the cross-sectional shape of the pseudo waveguide formed by the second divided waveguide tube 21 and the second waveguide tube 14 is the same as the length of the side c in the direction of the central axis O in the cross-sectional shape of the waveguide in the second divided waveguide tube 21, and is less than or equal to 1 / 2 wavelength of the wavelength of the signal transmitted in the tube.

[0079] Therefore, the transmission signal is not transmitted to the dummy waveguide formed at the position where the opening surface 21A of the second division waveguide 21 and the one surface of the second waveguide 14 face each other.

[0080] When the second waveguide 14 is linear, a dummy waveguide is formed at one end connected to the second coupling portion 12B at a position where one surface of the second waveguide 14 faces the opening surface 21A of the second split waveguide 21 .

[0081] The plurality of third waveguides 23A and 23B are respectively Figure 1 and Figure 7 As shown, on the other surface of the second division waveguide 21 opposite to the one surface, they are arranged at equal intervals with a gap between them, and are connected to the second division waveguide 21 via directional couplers 22A and 22B, respectively.

[0082] In the first embodiment, the plurality of third waveguides are the two third waveguides 23A and 23B. Hereinafter, the two third waveguides 23A and 23B will be described.

[0083] Furthermore, when there are three or more third waveguides, the three or more third waveguides also have the same structure.

[0084] The third waveguide 23A and the third waveguide 23B are arranged 180 degrees apart from each other along an arc centered on the central axis O. Figure 6 As shown in the cross-sectional shape of the third waveguide 23A, it is formed by an arc-shaped metallic conductor having another surface wall, an inner peripheral wall and an outer peripheral wall, and one surface wall is set as the other surface wall of the second divided waveguide 21.

[0085] The cross-sectional shape of the third waveguide 23A is as follows: Figure 6 Rectangle shown.

[0086] The cross-sectional shape of the waveguide in the third waveguide 23A is also a rectangle in which the length of the side d in the direction of the central axis O is longer than the length of the side perpendicular to the central axis O.

[0087] The length of the side d in the direction of the central axis O in the cross-sectional shape of the waveguide in the third waveguide 23A is longer than half the wavelength of the wavelength of the transmission signal in the tube.

[0088] The cross-sectional shape of the third waveguide 23B is also a rectangle of the same size as the cross-sectional shape of the third waveguide 23A.

[0089] The cross-sectional shape of the waveguide in the third waveguide 23B is also a rectangle in which the length of the side d in the direction of the central axis O is longer than the length of the side perpendicular to the central axis O.

[0090] The length of the side d in the direction of the central axis O in the cross-sectional shape of the waveguide in the third waveguide 23B is longer than half the wavelength of the in-tube wavelength of the transmission signal.

[0091] The two directional couplers 22A and 22B are arranged at positions separated by 180° on the other surface of the second division waveguide 21 .

[0092] The first directional coupler 22A and the second directional coupler 22B are each formed by one or more coupling holes formed on the other wall of the second division waveguide 21 , and transmit the transmission signal in one direction.

[0093] The third waveguide 23A is connected to the second division waveguide 21 via the first directional coupler 22A at one end, and is arranged to extend in one direction along the other surface of the second division waveguide 21 .

[0094] One end of the third waveguide 23A is terminated or short-circuited, and the other end is connected to the receiving circuit 41 .

[0095] The third waveguide 23B is connected to the second division waveguide 21 via the second directional coupler 22B at one end, and is arranged to extend in one direction along the other surface of the second division waveguide 21 .

[0096] One end of the third waveguide 23B is terminated or short-circuited, and the other end is connected to the receiving circuit 42 .

[0097] Next, regarding the operating principle and operation of the rotary joint involved in Embodiment 1, Figures 8 to 10 Provide explanation.

[0098] exist Figure 8 In the figure, as shown as X1 and X2, at the position where the opening surface 21A of the second split waveguide tube 21 and one surface of the second waveguide tube 14 are relative to each other, the length of the side c in the direction of the central axis O of the pseudo waveguide in the pseudo waveguide tube formed by the second split waveguide tube 21 and the second waveguide tube 14 is less than or equal to the length of 1 / 2 wavelength of the wavelength of the transmission signal in the tube, so the pseudo waveguide in the pseudo waveguide tube becomes cutoff for the transmission signal.

[0099] That is, the transmission signal is not transmitted in the pseudo waveguide in the pseudo waveguide formed by the second division waveguide 21 and the second waveguide 14 .

[0100] Similarly, in Figure 8 In the figure, at a position where the opening surface 21A of the second split waveguide tube 21 and a surface of the first waveguide tube 13 are relative to each other, the length of the side c in the direction of the central axis O in the pseudo waveguide formed by the second split waveguide tube 21 and the first waveguide tube 13 is less than or equal to the length of 1 / 2 wavelength of the wavelength of the transmission signal in the tube, so the pseudo waveguide in the pseudo waveguide tube becomes cutoff for the transmission signal.

[0101] That is, no Figure 8 In the transmission path in the direction of the arrow Y2 shown in the figure, the transmission signal is not transmitted in the dummy waveguide in the dummy waveguide formed by the second division waveguide 21 and the first waveguide 13 .

[0102] On the other hand, Figure 8 In the figure, as shown as X3 and X4, at the position where the opening surface 11A of the first split waveguide tube 11 and the opening surface 21A of the second split waveguide tube 21 are opposite to each other, the length of the side (b+c) in the direction of the central axis O in the waveguide formed by the first split waveguide tube 11 and the second split waveguide tube 21 is longer than 1 / 2 wavelength of the wavelength of the signal transmitted in the tube, so that the waveguide formed by the first split waveguide tube 11 and the second split waveguide tube 21 becomes a wavelength for transmitting the signal in the tube. Figure 8 The figure shows the transmission path that can be transmitted in the direction of the arrow Y1.

[0103] That is, although a transmission path is formed at a position where the opening surface 21A of the second split waveguide tube 21 is opposite to the opening surface 11A of the first split waveguide tube 11, and the transmission signal sent from the transmission circuit 30 can be transmitted in one direction through the waveguide of the waveguide tube formed by the first split waveguide tube 11 and the second split waveguide tube 21, since no transmission path is formed at positions where one side of the first waveguide tube 13 and one side of the second waveguide tube 14 are respectively opposite to each other, the transmission signal sent from the transmission circuit 30 becomes a one-way passage until the receiving circuit 41 or the receiving circuit 42.

[0104] Since the transmission signal transmitted from the transmission circuit 30 is transmitted to the reception circuit 41 or the reception circuit 42 in a one-way passage, there is no concern that a ring resonance mode is excited, and the transmission signal can be widened in bandwidth.

[0105] Currently, if Fig. 9 As shown, in Example 1 where the positional relationship between the stationary body 10 and the rotating body 20 is the first position, if a transmission signal is input from the transmission circuit 30 to the first waveguide tube 13, it is transmitted in the waveguide of the first waveguide tube 13 as shown by the arrows Y11 and Y12 in the figure, and as shown by the arrow Y13 in the figure, in the waveguide of the waveguide tube formed by the first split waveguide tube 11 and the second split waveguide tube 21 at positions where the opening surfaces 11A and 21A are relative to each other via the first coupling portion 12A, that is, in one direction in the transmission path, the transmission signal is transmitted clockwise as shown by the arrow Y14 in the figure in the first embodiment.

[0106] The transmission signal transmitted from the first coupling portion 12A to the transmission path is not transmitted through the pseudo waveguide formed by the second division waveguide 21 and the first waveguide 13 .

[0107] When the transmission signal transmitted in the transmission path reaches the second directional coupler 22B, the transmission signal is transmitted to the third waveguide 23B as shown by arrow Y15 in the figure, and is transmitted to the receiving circuit 42 as shown by arrows Y16 and Y17 in the figure, and is received by the receiving circuit 42.

[0108] The transmission signal transmitted in the transmission path as indicated by the arrow Y14 in the figure is not transmitted through the pseudo waveguide formed by the second division waveguide 21 and the second waveguide 14 .

[0109] The first position is a section in the rotating body 20 from the position where the second directional coupler 22B is located at the output end of the first coupling section 12A in the stationary body 10 to the position where the rotating body 20 is rotated 180 degrees in one direction.

[0110] The second position is a section from the position where the first directional coupler 22A is located at the output end of the first coupling section 12A in the stationary body 10 to the position where the rotating body 20 is rotated 180 degrees in one direction.

[0111] In addition, in order to facilitate Fig. 9 The position of Example 1 at the first position shown will be described, and the positional relationship between the stationary body 10 and the rotating body 20 is assumed to be 0°.

[0112] In summary, when the positional relationship between the stationary body 10 and the rotating body 20 of the rotary joint involved in embodiment 1 is the first position, a first transmission path is formed in which the transmission signal from the transmitting circuit 30 reaches the first connecting portion 12A (arrow Y13), the waveguide of the waveguide formed by the first split waveguide 11 and the second split waveguide 21 (arrow Y14), the second directional coupler 22B (arrow Y15), and the third waveguide 23B (arrow Y16 and arrow Y17).

[0113] At this time, the transmission signal transmitted in the first transmission path is unidirectional, and the ring resonance mode is not excited.

[0114] Next, it is assumed that, starting from Example 1 in which the positional relationship between the stationary body 10 and the rotating body 20 is at the first position, the rotating body 20 is rotated by 90° in one direction relative to the stationary body 10 .

[0115] This position is the position of Example 1 at the 2nd position. Fig.10 Shown.

[0116] like Fig.10 As shown, in Example 1 where the positional relationship between the stationary body 10 and the rotating body 20 is the second position, if a transmission signal is input from the transmission circuit 30 to the first waveguide tube 13, it is transmitted in the waveguide of the first waveguide tube 13 as shown by the arrows Y21 and Y22 in the figure, and as shown by the arrow Y23 in the figure, in the waveguide of the waveguide tube formed by the first split waveguide tube 11 and the second split waveguide tube 21 at the position where the opening surfaces 11A and 21A are relative to each other via the first coupling portion 12A, that is, the transmission signal is transmitted in one direction in the transmission path as shown by the arrow Y24 in the figure.

[0117] The transmission signal transmitted from the first coupling portion 12A to the transmission path is not transmitted through the pseudo waveguide formed by the second division waveguide 21 and the first waveguide 13 .

[0118] When the transmission signal transmitted in the transmission path reaches the first directional coupler 22A, the transmission signal is transmitted to the third waveguide 23A as shown by arrow Y25 in the figure, and is transmitted to the receiving circuit 41 as shown by arrows Y26 and Y27 in the figure, and is received by the receiving circuit 41.

[0119] The transmission signal transmitted in the transmission path as indicated by the arrow Y24 in the figure is not transmitted through the pseudo waveguide formed by the second division waveguide 21 and the second waveguide 14 .

[0120] In summary, when the positional relationship between the stationary body 10 and the rotating body 20 of the rotary joint involved in embodiment 1 is the second position, a second transmission path is formed in which the transmission signal from the transmitting circuit 30 reaches the first connecting portion 12A (arrow Y23), the waveguide of the waveguide formed by the first split waveguide 11 and the second split waveguide 21 (arrow Y24), the first directional coupler 22A (arrow Y25), and the third waveguide 23A (arrow Y26 and arrow Y27).

[0121] At this time, the transmission signal transmitted through the second transmission path is unidirectional, and the ring resonance mode is not excited.

[0122] In the above description, the situation in which the rotary joint involved in embodiment 1 transmits a sending signal in the first transmission path in Example 1 where the positional relationship between the stationary body 10 and the rotating body 20 is the first position, and the situation in which the sending signal is transmitted in the second transmission path in Example 1 where the positional relationship between the stationary body 10 and the rotating body 20 is the second position is described.

[0123] However, in the transition angle at which the rotating body 20 switches from the first conveying path to the second conveying path relative to the stationary body 10 , there are two conveying paths, namely the first conveying path and the second conveying path.

[0124] In summary, the positional relationship between the rotary joint involved in embodiment 1 and the stationary body 10 and the rotating body 20 corresponds to the ability to transmit the transmission signal from the transmitting circuit 30 to the receiving circuit 41, the receiving circuit 42, or the two receiving circuits 41 and 42 through three transmission paths, namely the first transmission path, the second transmission path, or the first transmission path and the second transmission path.

[0125] That is, the positional relationship of the rotating body 20 relative to the stationary body 10, that is, the rotation angle of the rotating body 20 can transmit the signal at the full rotation angle, control the positional relationship of the rotating body 20 relative to the stationary body 10, or switch the output from the receiving circuit 41 and the output from the receiving circuit 42 through a switch, thereby enabling the output from the receiving circuit 41 and the output from the receiving circuit 42 to be switched and output, or to be electrically synthesized and output.

[0126] Furthermore, the transmission signals transmitted through the first transmission path and the second transmission path are unidirectional and propagate in one direction, and the ring resonance mode is not excited.

[0127] As a result, the bandwidth of the transmitted signal can be widened.

[0128] In addition, the rotary joint involved in embodiment 1 sets the third waveguide to two, but when it is set to three, the three directional couplers are arranged at equal intervals, that is, at intervals of 120°, and the three third waveguides are respectively combined with the second split waveguide 21 through the corresponding directional couplers.

[0129] In this case, the positional relationship between the stationary body 10 and the rotating body 20 is in units of 120°, namely the first position, the second position, and the third position, and the rotary joint corresponds to the three third waveguides, respectively, to form the first transmission path, the second transmission path, and the third transmission path.

[0130] As described above, the rotary joint involved in the first embodiment includes: a stationary body 10, which has an arc-shaped first split waveguide 11 having a flat opening surface 11A on one side, and a first waveguide 13 whose one end is connected to one end of the first split waveguide 11 via a first connecting portion 12A; and a rotating body 20, which has an annular second split waveguide 21 having a flat opening surface 21A opposite to the opening surface 11A of the first split waveguide 11 on one side, and a plurality of third waveguides 23A, 23B, each of which is arranged on the other side of the second split waveguide 21 at intervals from each other and is connected to the second split waveguide 21 via directional couplers 22A, 22B. The rotating body 20 is freely rotatable relative to the stationary body 10 about the central axis O, and at the positions where the opening surfaces 11A and 21A are relative to each other, the second divided waveguide tube 21 and the first divided waveguide tube 11 form a waveguide tube, thereby forming a first transmission path formed by the first waveguide tube 13, the first joint 12A, the waveguide tube composed of the first divided waveguide tube 11 and the second divided waveguide tube 21, the directional coupler 22A and the third waveguide tube 23A, and a second transmission path formed by the first waveguide tube 13, the first joint 12A, the waveguide tube composed of the first divided waveguide tube 11 and the second divided waveguide tube 21, the directional coupler 22B and the third waveguide tube 23B.

[0131] The pseudo waveguide formed by the first waveguide 13 and the second divided waveguide 21 at a position where one side of the first waveguide 13 and the opening surface 21A of the second divided waveguide 21 are opposite to each other is set as a rectangle in which the length of the side parallel to the central axis O in the cross-sectional shape of the pseudo waveguide is less than or equal to 1 / 2 wavelength of the wavelength in the tube of the transmission signal; the pseudo waveguide formed by the second waveguide 14 and the second divided waveguide 21 at a position where one side of the second waveguide 14 and the opening surface 21A of the second divided waveguide 21 are opposite to each other is set as a rectangle in which the length of the side parallel to the central axis O in the cross-sectional shape of the pseudo waveguide is less than or equal to 1 / 2 wavelength of the wavelength in the tube of the transmission signal; therefore, the transmission signal is not transmitted to the pseudo waveguide, but is transmitted in one direction in the waveguide of the waveguide formed by the first divided waveguide 11 and the second divided waveguide 21 in a one-way manner.

[0132] As a result, the ring resonance mode is not excited, and the transmission signal can be widened in bandwidth.

[0133] Furthermore, since both the stationary body 10 and the rotating body 20 have a hollow portion in the center including the central axis O, various control lines can be routed in the hollow portion in the center.

[0134] Implementation method 2.

[0135] according to Figures 11 to 15 The rotary joint according to the second embodiment will be described.

[0136] In the rotary joint according to the first embodiment, the rotary body 20 has a plurality of third waveguides. In contrast, the rotary joint according to the second embodiment is different in that the rotary body 20 has one third waveguide, and the other points are the same.

[0137] exist Figures 11 to 15 in Figures 1 to 10 The same reference numerals as those in the drawings represent the same or corresponding parts.

[0138] The stationary body 10 is the same as the stationary body 10 in the rotary joint according to the first embodiment, and therefore the following description will focus on the rotary body 20 .

[0139] Rotating body 20 Fig.11 and Fig.13 As shown, there are a second split waveguide 21 and a third waveguide 23.

[0140] The second split waveguide 21 is as follows Fig.11 and Fig.13As shown, it is arranged along a circle having the same diameter as the arc of the first split waveguide tube 11 centered on the central axis O, and has a flat opening surface 21A on one side that is opposite to the opening surface 11A of the first split waveguide tube 11, one side of the first waveguide tube 13 and one side of the second waveguide tube 14.

[0141] The cross-sectional shape of the second segmented waveguide 21 is as follows: Fig.12 As shown, it has a shape having three sides of a rectangle except for the opening surface 21A.

[0142] That is, the second division waveguide 21 is formed by a ring-shaped metallic conductor having the other surface wall, the inner peripheral wall, and the outer peripheral wall connected around one circumference.

[0143] The first division waveguide 11 and the second division waveguide 21 constitute a waveguide at a position where an opening surface 11A of the first division waveguide 11 and an opening surface 21A of the second division waveguide 21 face each other.

[0144] At a position where the opening surface 11A of the first divided waveguide tube and the opening surface 21A of the second divided waveguide tube 21 are opposite to each other, a choke structure is used to arrange the end surface of the outer wall of the first divided waveguide tube 11 and the end surface of the outer wall of the second divided waveguide tube 21, and the end surface of the inner wall of the first divided waveguide tube 11 and the end surface of the inner wall of the second divided waveguide tube 21 in close proximity, so that the electromagnetic field generated by the electromagnetic wave serving as the transmission signal will not leak.

[0145] In addition, the configuration may be performed in a state where the end face of the outer wall of the first divided waveguide tube 11 and the end face of the outer wall of the second divided waveguide tube 21, and the end face of the inner wall of the first divided waveguide tube 11 and the end face of the inner wall of the second divided waveguide tube 21 are in direct contact and electrically conductive.

[0146] The length of the side c in the direction of the central axis O in the cross-sectional shape of the waveguide in the second divided waveguide 21 is the same as the length of the side b in the direction of the central axis O in the cross-sectional shape of the waveguide in the first divided waveguide 11 .

[0147] That is, the cross-sectional shape of the waveguide in the waveguide tube formed by the first divided waveguide tube 11 and the second divided waveguide tube 21 is rectangular, and the side (b+c) in the cross-sectional shape of the waveguide in the direction of the central axis O is longer than the length of the side perpendicular to the central axis O and longer than 1 / 2 wavelength of the wavelength of the transmitted signal in the tube.

[0148] Furthermore, although the lengths of side b and side c are set to be the same, if the length of side (b+c) is longer than 1 / 2 wavelength of the wavelength of the transmission signal in the tube, the lengths of side b and side c can be set to different lengths.

[0149] However, the length of the side c is less than or equal to 1 / 2 wavelength of the wavelength of the transmission signal in the tube.

[0150] The second division waveguide 21 and the first waveguide 13 form a dummy waveguide at a position where an opening surface 21A of the second division waveguide 21 and a surface of the first waveguide 13 face each other.

[0151] The length of the side c in the direction of the central axis O in the cross-sectional shape of the pseudo waveguide formed by the second divided waveguide tube 21 and the first waveguide tube 13 is the same as the length of the side c in the direction of the central axis O in the cross-sectional shape of the waveguide in the second divided waveguide tube 21, and is less than or equal to 1 / 2 wavelength of the wavelength of the signal transmitted in the tube.

[0152] Therefore, the transmission signal is not transmitted to the dummy waveguide formed at the position where the opening surface 21A of the second division waveguide 21 and the one surface of the first waveguide 13 face each other.

[0153] When the first waveguide 13 is formed into a straight line, a dummy waveguide is formed at a position where one surface of the first waveguide 13 faces the opening surface 21A of the second split waveguide 21 at one end connected to the first coupling portion 12A.

[0154] The second division waveguide 21 and the second waveguide 14 constitute a dummy waveguide at a position where an opening surface 21A of the second division waveguide 21 and a surface of the second waveguide 14 face each other.

[0155] The length of the side c in the direction of the central axis O in the cross-sectional shape of the pseudo waveguide formed by the second divided waveguide tube 21 and the second waveguide tube 14 is the same as the length of the side c in the direction of the central axis O in the cross-sectional shape of the waveguide in the second divided waveguide tube 21, and is less than or equal to 1 / 2 wavelength of the wavelength of the transmitted signal in the tube.

[0156] Therefore, the transmission signal is not transmitted to the dummy waveguide formed at the position where the opening surface 21A of the second division waveguide 21 and the one surface of the second waveguide 14 face each other.

[0157] When the second waveguide 14 is linear, a dummy waveguide is formed at one end connected to the second coupling portion 12B at a position where one surface of the second waveguide 14 faces the opening surface 21A of the second split waveguide 21 .

[0158] The third waveguide 23 is as follows Fig.11 and Fig.13As shown, the second split waveguide 21 is connected to the second split waveguide 21 via a plurality of directional couplers 22A and 22B which are arranged in an annular shape along the other surface of the second split waveguide 21 and are arranged at equal intervals along the circumference.

[0159] The third waveguide 23 is as shown in Fig.12 As shown in the cross-sectional shape in FIG, the second division waveguide 21 has another wall, an inner peripheral wall, and an outer peripheral wall, and one wall is formed by a ring-shaped metallic conductor serving as the other wall of the second division waveguide 21.

[0160] The cross-sectional shape of the third waveguide 23 is as follows: Fig.12 Rectangle shown.

[0161] The cross-sectional shape of the waveguide in the third waveguide tube 23 is also a rectangle in which the length of the side d in the direction of the central axis O is longer than the length of the side perpendicular to the central axis O.

[0162] The length of the side d in the direction of the central axis O in the cross-sectional shape of the waveguide in the third waveguide 23 is longer than half the wavelength of the in-tube wavelength of the transmission signal.

[0163] One end of the third waveguide 23 is connected to the receiving circuit 40 , and the other end is short-circuited or serves as a terminal 60 .

[0164] In the second embodiment, the plurality of directional couplers are two directional couplers 22A and 22B that are arranged 180 degrees apart from each other. The two directional couplers 22A and 22B will be described below.

[0165] One end of the third waveguide 23 connected to the receiving circuit 40 and the other end of the third waveguide 23 short-circuited or terminated 60 are arranged at a position between the first directional coupler 22A and the second directional coupler 22B.

[0166] Furthermore, when there are three or more directional couplers, the directional couplers have the same structure and are arranged at intervals of 120°.

[0167] Next, regarding the operation of the rotary joint according to Embodiment 2, Fig.14 and Fig.15 Provide explanation.

[0168] Currently, if Fig.14As shown, in Example 1 where the positional relationship between the stationary body 10 and the rotating body 20 is the first position, if a transmission signal is input from the transmission circuit 30 to the first waveguide tube 13, it is transmitted in the waveguide of the first waveguide tube 13 as shown by the arrows Y31 and Y32 in the figure, and as shown by the arrow Y33 in the figure, in the waveguide of the waveguide tube formed by the first split waveguide tube 11 and the second split waveguide tube 21 at positions where the opening surfaces 11A and 21A are relative to each other via the first coupling portion 12A, that is, in one direction in the transmission path, the transmission signal is transmitted clockwise as shown by the arrow Y34 in the figure in the second embodiment.

[0169] The transmission signal transmitted from the first coupling portion 12A to the transmission path is not transmitted through the pseudo waveguide formed by the second division waveguide 21 and the first waveguide 13 .

[0170] Therefore, the first directional coupler 22A located on the other surface of the first waveguide 13 does not transmit the transmission signal to the pseudo waveguide formed by the second division waveguide 21 and the first waveguide 13 , and therefore the first directional coupler 22A does not operate.

[0171] When the transmission signal transmitted in the transmission path reaches the second directional coupler 22B, the transmission signal is transmitted to the third waveguide 23 as shown by arrow Y35 in the figure, and is transmitted to the receiving circuit 40 as shown by arrows Y36 and Y37 in the figure, and is received by the receiving circuit 40.

[0172] The transmission signal transmitted in the transmission path as indicated by the arrow Y34 in the figure is not transmitted through the pseudo waveguide formed by the second division waveguide 21 and the second waveguide 14 .

[0173] The first position is a section in the rotating body 20 from the position where the second directional coupler 22B is located at the output end of the first coupling section 12A in the stationary body 10 to the position where the rotating body 20 is rotated 180 degrees in one direction.

[0174] The second position is a section from the position where the first directional coupler 22A is located at the output end of the first coupling section 12A in the stationary body 10 to the position where the rotating body 20 is rotated 180 degrees in one direction.

[0175] In addition, in order to facilitate Fig.14 The position of Example 1 at the first position shown will be described, and the positional relationship between the stationary body 10 and the rotating body 20 is set to 0°.

[0176] In summary, when the positional relationship between the stationary body 10 and the rotating body 20 of the rotary joint involved in embodiment 2 is the first position, a first transmission path is formed in which the transmission signal from the transmitting circuit 30 reaches the first connecting portion 12A (arrow Y33), the waveguide of the waveguide formed by the first split waveguide 11 and the second split waveguide 21 (arrow Y34), the second directional coupler 22B (arrow Y35), and the third waveguide 23 (arrow Y36 and arrow Y37).

[0177] At this time, the transmission signal transmitted in the first transmission path is unidirectional, and the ring resonance mode is not excited.

[0178] Next, it is assumed that, starting from Example 1 in which the positional relationship between the stationary body 10 and the rotating body 20 is at the first position, the rotating body 20 rotates by 135° in one direction relative to the stationary body 10 .

[0179] This position is the position of Example 1 at the 2nd position. Fig.15 Shown.

[0180] like Fig.15 As shown, in Example 1 where the positional relationship between the stationary body 10 and the rotating body 20 is at the second position, if a transmission signal is input from the transmission circuit 30 to the first waveguide tube 13, it is transmitted in the waveguide of the first waveguide tube 13 as shown by the arrows Y41 and Y42 in the figure, and as shown by the arrow Y43 in the figure, in the waveguide of the waveguide tube formed by the first split waveguide tube 11 and the second split waveguide tube 21 at positions where the opening surfaces 11A and 21A are relative to each other via the first coupling portion 12A, that is, the transmission signal is transmitted in one direction in the transmission path as shown by the arrow Y44 in the figure.

[0181] The transmission signal transmitted from the first coupling portion 12A to the transmission path is not transmitted through the pseudo waveguide formed by the second division waveguide 21 and the first waveguide 13 .

[0182] When the transmission signal transmitted in the transmission path reaches the first directional coupler 22A, the transmission signal is transmitted to the third waveguide 23 as shown by arrow Y45 in the figure, and is transmitted to the receiving circuit 40 as shown by arrows Y46 and Y47 in the figure, and is received by the receiving circuit 40.

[0183] The transmission signal transmitted in the transmission path as indicated by the arrow Y44 in the figure is not transmitted through the pseudo waveguide formed by the second division waveguide 21 and the second waveguide 14 .

[0184] In addition, the length of the side c in the direction of the central axis O in the pseudo waveguide formed by the second split waveguide 21 and the second waveguide 14 is less than or equal to the length of 1 / 2 wavelength of the wavelength of the transmitted signal in the tube. Therefore, the transmission signal transmitted to the third waveguide 23 on the second directional coupler 22B located on the other side of the second waveguide 14 is not affected by the second directional coupler 22B and passes directly.

[0185] In summary, the rotary joint involved in embodiment 2 forms a second transmission path in which the transmission signal from the transmitting circuit 30 reaches from the first waveguide tube 13 (arrows Y41 and Y42) to the first coupling portion 12A (arrow Y43), the waveguide of the waveguide tube formed by the first split waveguide tube 11 and the second split waveguide tube 21 (arrow Y44), the first directional coupler 22A (arrow Y45), and the third waveguide tube 23A (arrows Y46 and Y47) when the positional relationship between the stationary body 10 and the rotating body 20 is the second position.

[0186] At this time, the transmission signal transmitted through the second transmission path is unidirectional, and the ring resonance mode is not excited.

[0187] In the above description, it is explained that the rotary joint involved in embodiment 2 transmits the transmission signal in the first transmission path in Example 1 where the positional relationship between the stationary body 10 and the rotating body 20 is the first position, and transmits the transmission signal in the second transmission path in Example 1 where the positional relationship between the stationary body 10 and the rotating body 20 is the second position.

[0188] However, in the transition angle at which the rotating body 20 switches from the first conveying path to the second conveying path relative to the stationary body 10 , there are two conveying paths, namely the first conveying path and the second conveying path.

[0189] In summary, the rotary joint involved in embodiment 2 corresponds to the positional relationship between the stationary body 10 and the rotating body 20, and can transmit the transmission signal from the transmitting circuit 30 to the receiving circuit 40 through three transmission paths: the first transmission path, the second transmission path, or both the first transmission path and the second transmission path.

[0190] That is, the positional relationship of the rotating body 20 relative to the stationary body 10, that is, the rotation angle of the rotating body 20 is capable of transmitting the sending signal at the full rotation angle, and the positional relationship of the rotating body 20 relative to the stationary body 10 is controlled, thereby being able to switch to the first transmission path or the second transmission path to output the output from the receiving circuit 40, or to output by synthesizing the power of the two transmission paths, the first transmission path and the second transmission path.

[0191] Furthermore, the transmission signals transmitted through the first transmission path and the second transmission path are unidirectional and propagate in one direction, and the ring resonance mode is not excited.

[0192] As a result, the bandwidth of the transmitted signal can be widened.

[0193] Furthermore, the rotary joint according to the first embodiment has two directional couplers, but three directional couplers may be arranged at equal intervals, that is, at intervals of 120°, and the third waveguide 23 may be connected to the second split waveguide 21 via the directional couplers arranged at equal intervals.

[0194] In this case, the positional relationship between the stationary body 10 and the rotating body 20 is in units of 120°, namely the first position, the second position, and the third position, and the rotary joint and the three third waveguides respectively form the first transmission path, the second transmission path, and the third transmission path.

[0195] As described above, the rotary joint involved in the second embodiment includes: a stationary body 10, which has an arc-shaped first split waveguide 11 having a flat opening surface 11A on one side, and a first waveguide 13 whose one end is connected to one end of the first split waveguide 11 via a first connecting portion 12A; and a rotating body 20, which has an annular second split waveguide 21 having a flat opening surface 21A on one side opposite to the opening surface 11A of the first split waveguide 11, and a plurality of directional couplers 22A and 22B arranged along the circumference of the second split waveguide 21 at intervals from each other and connected to the second split waveguide 21 via a first connecting portion 12A. The rotating body 20 is freely rotatable relative to the stationary body 10 about the central axis O, and the second divided waveguide 21 and the first divided waveguide 11 form a waveguide at the position where the opening surfaces 11A and 21A are relative to each other, thereby forming a first transmission path formed by the first waveguide 13, the first connecting portion 12A, the waveguide composed of the first divided waveguide 11 and the second divided waveguide 21, the directional coupler 22A and the third waveguide 23, and a second transmission path formed by the first waveguide 13, the first connecting portion 12A, the waveguide composed of the first divided waveguide 11 and the second divided waveguide 21, the directional coupler 22B and the third waveguide 23.

[0196] The pseudo waveguide formed by the first waveguide 13 and the second divided waveguide 21 at a position where one side of the first waveguide 13 and the opening surface 21A of the second divided waveguide 21 are opposite to each other is set as a rectangle in which the length of the side parallel to the central axis O in the cross-sectional shape of the pseudo waveguide is less than or equal to 1 / 2 wavelength of the wavelength in the tube of the transmission signal; the pseudo waveguide formed by the second waveguide 14 and the second divided waveguide 21 at a position where one side of the second waveguide 14 and the opening surface 21A of the second divided waveguide 21 are opposite to each other is set as a rectangle in which the length of the side parallel to the central axis O in the cross-sectional shape of the pseudo waveguide is less than or equal to 1 / 2 wavelength of the wavelength in the tube of the transmission signal. Therefore, the transmission signal is not transmitted to the pseudo waveguide, but is transmitted in one direction in the waveguide of the waveguide formed by the first divided waveguide 11 and the second divided waveguide 21 in a unidirectional manner.

[0197] As a result, the ring resonance mode is not excited, and the transmission signal can be widened in bandwidth.

[0198] Furthermore, the present invention can be a free combination of the various embodiments, or arbitrary components of the various embodiments can be modified, or arbitrary components can be omitted in the various embodiments.

[0199] Industrial Applicability

[0200] The rotary joint according to the present invention is suitable for use in a communication system or a microwave communication system for controlling a hand portion of a robot arm.

[0201] Description of the label

[0202] 10 stationary body, 11 first split waveguide, 11A opening surface, 12A first connecting portion, 12B second connecting portion, 13 first waveguide, 14 second waveguide, 20 rotating body, 21 second split waveguide, 21A opening surface, 22A first directional coupler, 22B second directional coupler, 23, 23A, 23B third waveguide, 30 transmitting circuit, 40, 41, 42 receiving circuit, 50 terminal resistance or short circuit, 60 terminal resistance or short circuit.

Claims

1. A rotary joint, comprising: a stationary body, which is arranged along an arc centered on a central axis, and has a first split waveguide having a flat opening surface on one side, a first waveguide having one end connected to one end of the first split waveguide via a first connecting portion, and a second waveguide having one end connected to the other end of the first split waveguide via a second connecting portion; and A rotating body is arranged along a circle with the same diameter as the arc on which the first split waveguide tube is arranged, with the central axis as the center, and has an annular second split waveguide tube having a flat opening surface on one side opposite to the opening surface of the first split waveguide tube, and a plurality of third waveguide tubes each arranged at a distance from each other on the other side of the second split waveguide tube opposite to the one side, each of which is connected to the second split waveguide tube via a directional coupler, the rotating body being freely rotatable with respect to the stationary body with the central axis as the center, and the second split waveguide tube and the first split waveguide tube forming a waveguide tube at a position where their opening surfaces are opposite to each other.

2. The rotary joint according to claim 1, wherein: The plurality of third waveguides are two third waveguides, One of the two third waveguides is connected to the second split waveguide through one of the two directional couplers arranged at positions separated by 180 degrees on the other side of the second split waveguide, and is arranged to extend in one direction along the circumference of the second split waveguide. The other of the two third waveguides is coupled to the second division waveguide via the other of the two directional couplers, and is arranged to extend in one direction along the circumference of the second division waveguide.

3. The rotary joint according to claim 2, wherein: The other end of the first waveguide is connected to a transmission circuit for outputting a signal. The other end of the second waveguide is short-circuited or terminated. One end of one of the two third waveguides located on the side of the one directional coupler is short-circuited or terminated, and the other end extending in one direction from the one end is connected to the receiving circuit. One end of the other third waveguide of the two third waveguides, which is located on the other directional coupler side, is short-circuited or terminated, and the other end extending in one direction from the one end is connected to the receiving circuit.

4. The rotary joint according to claim 3, wherein: At a positional relationship between the stationary body and the rotating body of the first position, a signal input from the transmitting circuit to the first waveguide is transmitted through the first coupling portion in a waveguide composed of the first split waveguide and the second split waveguide at a position where the opening surfaces of the first waveguide are opposite to each other, thereby forming a transmission path that is transmitted from the one directional coupler to one of the two third waveguides and reaches the other end of one of the two third waveguides. When the positional relationship between the stationary body and the rotating body is the second position, the signal input from the transmitting circuit to the first waveguide is transmitted through the first coupling portion in the waveguide formed by the first split waveguide and the second split waveguide at a position relative to each other through their opening surfaces, thereby forming a transmission path that is transmitted from the other directional coupler to the other third waveguide of the two third waveguides and reaches the other end of the other third waveguide of the two third waveguides.

5. The rotary joint according to claim 3, wherein: A signal from a receiving circuit connected to the other end of one of the two third waveguides and a signal from a receiving circuit connected to the other end of the other of the two third waveguides are switched and output or are electrically combined and output.

6. The rotary joint according to any one of claims 1 to 5, wherein: It is a rectangle in which the length of the side in the direction of the central axis is longer than the length of the side perpendicular to the central axis in the cross-sectional shape along the direction of the central axis of the waveguide in the waveguide tube formed by the first divided waveguide tube and the second divided waveguide tube at positions relative to each other's opening surfaces.

7. The rotary joint according to claim 6, wherein: The length of the side in the central axis direction in the cross-sectional shape of the waveguide formed by the first divided waveguide and the second divided waveguide is longer than 1 / 2 wavelength of the wavelength of the signal transmitted in the tube.

8. The rotary joint according to any one of claims 1 to 5, wherein: The first waveguide is arranged along an arc centered on the central axis, with one side facing the opening surface of the second split waveguide. At a position where one surface of the first waveguide and the opening surface of the second split waveguide are opposite to each other, a cross-sectional shape of a pseudo waveguide in a pseudo waveguide formed by the first waveguide and the second split waveguide along the direction of the central axis is a rectangle whose side length in the direction of the central axis is less than or equal to 1 / 2 wavelength of a wavelength in the tube for transmitting a signal, The second waveguide is arranged along an arc centered on the central axis, with one side facing the opening surface of the second split waveguide. The cross-sectional shape along the direction of the central axis of the pseudo waveguide in the pseudo waveguide formed by the second waveguide and the second split waveguide at a position relative to one side of the second waveguide and the opening surface of the second split waveguide is a rectangle whose length in the direction of the central axis is less than or equal to 1 / 2 wavelength of the wavelength of the signal transmitted in the tube.

9. The rotary joint according to claim 6, wherein: The first waveguide is arranged along an arc centered on the central axis, with one side facing the opening surface of the second split waveguide. At a position where one surface of the first waveguide and the opening surface of the second split waveguide are opposite to each other, a cross-sectional shape of a pseudo waveguide in a pseudo waveguide formed by the first waveguide and the second split waveguide along the direction of the central axis is a rectangle whose side length in the direction of the central axis is less than or equal to 1 / 2 wavelength of a wavelength in the tube for transmitting a signal, The second waveguide is arranged along an arc centered on the central axis, with one side facing the opening surface of the second split waveguide. At a position where one surface of the second waveguide tube and the opening surface of the second split waveguide tube are relative to each other, the cross-sectional shape of the pseudo waveguide in the pseudo waveguide tube formed by the second waveguide tube and the second split waveguide tube along the central axis is a rectangle whose length in the direction of the central axis is less than or equal to 1 / 2 wavelength of the wavelength of the transmitted signal in the tube.

10. A rotary joint, comprising: a stationary body, which is arranged along an arc centered on a central axis, and has a first split waveguide having a flat opening surface on one side, a first waveguide having one end connected to one end of the first split waveguide via a first connecting portion, and a second waveguide having one end connected to the other end of the first split waveguide via a second connecting portion; and A rotating body, which is arranged along a circumference of a circle having the same diameter as the arc on which the first split waveguide tube is arranged, with the central axis as the center, and has an annular second split waveguide tube having a flat opening surface on one side opposite to the opening surface of the first split waveguide tube, and a third waveguide tube arranged along a circumference on the other side of the second split waveguide tube opposite to the one side, and connected to the second split waveguide tube via a plurality of directional couplers arranged at intervals from each other along the circumference of the second split waveguide tube, the rotating body being freely rotatable with respect to the stationary body with the central axis as the center, and the second split waveguide tube and the first split waveguide tube forming a waveguide tube at positions where their opening surfaces are opposite to each other.

11. The rotary joint according to claim 10, wherein: The plurality of directional couplers are two directional couplers arranged at positions separated by 180 degrees on the other surface of the second division waveguide.

12. The rotary joint according to claim 11, wherein: The other end of the first waveguide is connected to a transmission circuit for outputting a signal. The other end of the second waveguide is short-circuited or terminated. One end of the third waveguide is connected to the receiving circuit, and the other end is short-circuited or terminated.

13. The rotary joint according to claim 12, wherein: When the positional relationship between the stationary body and the rotating body is the first position, the signal input from the transmitting circuit to the first waveguide is transmitted through the first joint portion in the waveguide composed of the first split waveguide and the second split waveguide at the position where the opening surfaces of each other are opposite to each other, thereby forming a transmission path from the one directional coupler to one end of the third waveguide. When the positional relationship between the stationary body and the rotating body is the second position, the signal input from the transmitting circuit to the first waveguide is transmitted through the first coupling portion, in the waveguide formed by the first split waveguide and the second split waveguide at positions relative to each other through their opening surfaces, thereby forming a transmission path from the other directional coupler to one end of the third waveguide.

14. The rotary joint according to claim 12, wherein: A signal from a receiving circuit connected to one end of the third waveguide at the first position and a signal from a receiving circuit connected to one end of the third waveguide at the second position are switched and output or are electrically combined and output.

15. The rotary joint according to any one of claims 10 to 14, wherein: It is a rectangle in which the length of the side in the direction of the central axis is longer than the length of the side perpendicular to the central axis in the cross-sectional shape along the direction of the central axis of the waveguide in the waveguide tube formed by the first divided waveguide tube and the second divided waveguide tube at positions relative to each other's opening surfaces.

16. The rotary joint according to claim 15, wherein: The length of the side in the central axis direction in the cross-sectional shape of the waveguide formed by the first divided waveguide and the second divided waveguide is longer than half the wavelength of the in-tube wavelength of the transmission signal.

17. A rotary joint according to any one of claims 10 to 14, wherein: The first waveguide is arranged along an arc centered on the central axis, with one side facing the opening surface of the second split waveguide. At a position where one surface of the first waveguide and the opening surface of the second split waveguide are opposite, the cross-sectional shape of the pseudo waveguide in the pseudo waveguide formed by the first waveguide and the second split waveguide along the direction of the central axis is a rectangle whose side length in the direction of the central axis is less than or equal to 1 / 2 wavelength of the wavelength of the signal transmitted in the tube, The second waveguide is arranged along an arc centered on the central axis, with one side facing the opening surface of the second split waveguide. At a position where one side of the second waveguide tube and the opening surface of the second split waveguide tube are relative to each other, the cross-sectional shape of the pseudo waveguide in the pseudo waveguide tube formed by the second waveguide tube and the second split waveguide tube along the direction of the central axis is a rectangle whose length in the direction of the central axis is less than or equal to 1 / 2 wavelength of the wavelength of the transmitted signal in the tube.

18. The rotary joint according to claim 15, wherein: The first waveguide is arranged along an arc centered on the central axis, with one side facing the opening surface of the second split waveguide. At a position where one surface of the first waveguide and the opening surface of the second split waveguide are opposite, the cross-sectional shape of the pseudo waveguide in the pseudo waveguide formed by the first waveguide and the second split waveguide along the direction of the central axis is a rectangle whose side length in the direction of the central axis is less than or equal to 1 / 2 wavelength of the wavelength of the signal transmitted in the tube, The second waveguide is arranged along an arc centered on the central axis, with one side facing the opening surface of the second split waveguide. At a position where one side of the second waveguide tube and the opening surface of the second split waveguide tube are relative to each other, the cross-sectional shape of the pseudo waveguide in the pseudo waveguide tube formed by the second waveguide tube and the second split waveguide tube along the direction of the central axis is a rectangle whose length in the direction of the central axis is less than or equal to 1 / 2 wavelength of the wavelength in the tube of the transmitted signal.

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