Microwave rotary joint

Abstract

The application discloses a microwave rotary joint and relates to the technical field of high-power microwave, which comprises a base, a rotating part, a bellows and a fixed sealing part. The base is in a ring structure, and the left end of the base is used for fixed sealing connection with an input device. The rotating part is in a ring structure, coaxially arranged at the right end of the base and capable of rotating around its own axis, and the right end of the rotating part is used for fixed sealing connection with an output device. The rotating part and the base have a gap therebetween to form a choke groove. The bellows is coaxially sleeved outside the rotating part, and the left end of the bellows is sealingly connected with the right end of the base. At least part of the structure of the fixed sealing part is located between the bellows and the rotating part, so that rotating sealing connection is formed between the inner side wall of the bellows and the outer side wall of the rotating part. The rotary joint can reliably maintain a high-vacuum sealing environment inside a transmission channel in a rotating state, reduces the risk of air breakdown discharge, and meets the transmission requirements of a high-power microwave system.

Description

Technical Field

[0001] This invention relates to the field of high-power microwave technology, and in particular to a microwave rotary joint. Background Technology

[0002] High-power microwave technology is increasingly used in civilian fields such as industrial heating, medical irradiation, and large scientific facilities, placing higher demands on the flexibility of system layout and the adaptability of deployment. A typical high-power microwave system generally includes a pulse drive source, microwave generating devices, a microwave transmission link, and end-radiation devices. Among these, the pulse drive source and microwave generating devices usually contain heavy components, and the components are rigidly connected and generally fixed on a base platform, making it inconvenient to move with the end devices. Therefore, in engineering practice, a rotary joint is usually introduced into the microwave transmission link as an electromechanical coupling hub connecting the stationary and moving sections, enabling continuous and reliable transmission of microwave energy on both sides of the rotating interface.

[0003] For the rotary joints in the above application scenarios, the following requirements must be met simultaneously: First, the structure should be compact to avoid spatial interference with other components in the transmission link; second, in a stationary state, the input and output ports of the rotary joint should have high coaxial accuracy and ensure that high-power microwave energy can pass through the rotating interface with low reflection and low insertion loss; third, the support end-radiating device should be able to rotate continuously within a predetermined angle range, and the rotation speed should meet the dynamic response requirements of the target application.

[0004] However, microwave rotary joints in conventional communications typically do not prioritize high vacuum sealing in their design. They often employ ordinary sealing rings or clearance fits to achieve a seal between the rotating shaft and the base, resulting in limited vacuum retention within the transmission channel. Under high-power microwave transmission conditions, residual gas within the channel is highly susceptible to ionization and breakdown discharge under a strong electric field. This not only causes significant microwave energy loss but may also damage the transmission devices themselves. High-power microwave systems typically have stringent requirements for the vacuum level of the transmission channel (generally better than 10⁻⁶). -3 (Pa level), conventional sealing solutions for rotary joints are insufficient to meet this vacuum level requirement.

[0005] In summary, how to provide a rotating joint that can reliably maintain a high vacuum sealing environment inside the transmission channel while rotating and reduce transmission loss is a technical problem that urgently needs to be solved in current high-power microwave applications, and it is also one of the key bottlenecks restricting the further development of this technology towards practical engineering applications. Summary of the Invention

[0006] The purpose of this invention is to provide a microwave rotary joint to solve the technical problem of insufficient vacuum sealing performance of existing rotary joints under high-power microwave transmission conditions, thereby reliably maintaining a high vacuum environment inside the transmission channel and reducing the risk of internal breakdown and transmission loss. To achieve the above objective, this invention provides the following solution: This invention provides a microwave rotary joint, comprising a base, a rotating part, a bellows, and a fixed sealing part. The base has an annular structure, and its left end is used for a fixed and sealed connection with an input device. The rotating part has an annular structure and is coaxially disposed at the right end of the base. The rotating part is rotatable about its own axis, and its right end is used for a fixed and sealed connection with an output device. A gap exists between the left end of the rotating part and the right end of the base to form a choke groove. The left end of the bellows is sealed to the right end of the base, and the bellows is coaxially sleeved on a portion of the outer side of the rotating part. The fixed sealing part is sealed to the right end of the bellows and is coaxially sleeved on the outer side of the rotating part. At least a portion of the fixed sealing part is disposed between the bellows and the rotating part, so that the inner wall of the bellows and the outer wall of the rotating part are rotatably and sealed together.

[0007] In some embodiments, the fixed sealing part includes a sealing part and a plurality of fixing parts. The outer side of the sealing part is sealed to the right end of the bellows, and the inner side of the sealing part is rotatably sealed to a portion of the outer side wall of the rotating part. Each of the fixing parts is evenly distributed circumferentially along the outer side wall of the bellows. The left end of each fixing part is fixedly connected to the right end of the base, and the right end of each fixing part is fixedly connected to the outer side of the sealing part, so as to support the axial space of the bellows between the base and the outer side of the sealing part.

[0008] In some embodiments, the base is a conductor, and the base includes an annular cylindrical tube, a first flange edge, and a second flange edge; the first flange edge is fixedly disposed on the circumferential edge of the left end of the annular cylindrical tube for fixed and sealed connection with the input device; the second flange edge is fixedly disposed on the circumferential edge of the right end of the annular cylindrical tube for fixed connection with the left end of each of the fixing parts.

[0009] In some embodiments, the sealing part includes a sealing ring outer flange, a rotating sealing limiter, and a rotating sealing assembly. The right end of the fixed part is fixedly connected to the outer ring of the sealing ring outer flange, and the right end of the bellows abuts against the inner ring of the sealing ring outer flange. The rotating sealing limiter is fixedly disposed on the inner side wall of the sealing ring outer flange. The rotating sealing assembly is disposed between the inner side of the rotating sealing limiter and a portion of the outer side wall of the rotating part, so that the portion of the outer side wall of the rotating part is rotatably sealed to the rotating sealing limiter.

[0010] In some embodiments, a protruding end is fixedly provided on the inner side of the second flange edge of the base. The choke groove includes a gap between the protruding end and the left end of the rotating part, and a gap recessed to the left on the outer side of the protruding end on the base. The length of the choke groove in the axial direction of the base is 1 / 4 of the free space wavelength corresponding to the working frequency. The length of the choke groove in the radial direction of the base is 1 / 4 of the free space wavelength corresponding to the working frequency. The edge of the protruding end is provided with an arc-shaped chamfer.

[0011] In some embodiments, an annular first sealing groove coaxial with the base is formed on the right side of the second flange edge of the base. A first stepped structure is also provided inside the first sealing groove. A third stepped structure corresponding to the first stepped structure is provided on the left end face of the bellows. An annular second sealing groove coaxial with the base is formed on the left side of the outer flange of the sealing ring. A second stepped structure is also provided inside the second sealing groove. A fourth stepped structure corresponding to the second stepped structure is provided on the right end face of the bellows. The first and second sealing grooves are located within... All are equipped with sealing rings. The first stepped structure on the second flange of the base is sealed to the third stepped structure on the bellows. The left end face of the bellows presses against the sealing ring in the first sealing groove so that the left end face of the bellows abuts against the right side of the second flange of the base. The second stepped structure on the outer flange of the sealing ring is sealed to the fourth stepped structure on the bellows. The right end face of the bellows presses against the sealing ring in the second sealing groove so that the right end face of the bellows abuts against the left side of the outer flange of the sealing ring.

[0012] In some embodiments, the rotating sealing assembly includes, from left to right, a first ball bearing, a first sealing ring, a tapered metal sealing gasket, a second sealing ring, a metal sealing gasket, a sealing clamping flange, and a second ball bearing. A first annular protrusion is provided on the inner wall of the rotating sealing limiting member. An annular first mounting groove is formed on the inner wall of the rotating sealing limiting member to the left of the first annular protrusion. A first retaining ring is embedded in the first mounting groove. The first ball bearing is disposed between the first retaining ring and the first annular protrusion. The first sealing ring, the tapered metal sealing gasket, the second sealing ring, and the metal sealing gasket are all arranged from left to right on the right side of the annular protrusion, filling the gap between the inner side of the rotating sealing limiting member and the outer wall of the rotating part. A fifth stepped structure is also provided on the inner wall of the rotating sealing limiting member, and the inner diameter of the right side of the fifth stepped structure is larger than the inner diameter of the left side. The sealing clamping method... The flange has a sealing edge and a pressing edge arranged perpendicularly to each other. A sixth-step structure is provided at the connection between the sealing edge and the pressing edge of the sealing and pressing flange. The sealing edge of the sealing and pressing flange is fixedly connected to the rotating sealing limit member on the right side of the fifth-step structure. The pressing edge of the sealing and pressing flange presses against the first sealing ring, the conical metal sealing gasket, the second sealing ring, and the metal sealing flat gasket from the right side. The sixth-step structure of the sealing and pressing flange can seal and cooperate with the right side of the fifth-step structure on the inner side wall of the rotating sealing limit member. A seventh-step structure is provided on the outer side wall of the rotating part. The outer diameter of the rotating part on the right side of the seventh-step structure is smaller than the outer diameter on the left side. An annular second mounting groove is opened on the outer side wall of the rotating part on the right side of the seventh-step structure. A second retaining ring is embedded in the second mounting groove. The second ball bearing is disposed between the second retaining ring and the second annular protrusion.

[0013] In some embodiments, the fixed sealing part further includes a plurality of first gaskets and a plurality of second gaskets. Each first gasket is evenly distributed circumferentially along the outer side wall of the bellows. Each first gasket is fixedly connected to the second flange edge of the base to press the left end face of the bellows against the first sealing groove and the first stepped structure on the right side surface of the second flange edge of the base. Each second gasket is evenly distributed circumferentially along the outer side wall of the bellows. Each second gasket is fixedly connected to the outer flange of the sealing ring to press the right end face of the bellows against the second sealing groove and the second stepped structure on the left side surface of the outer flange of the sealing ring.

[0014] In some embodiments, the rotating part includes a rotating shaft, a first flange edge of the rotating part, and a second flange edge of the rotating part. The rotating shaft is hollow, and the rotating sealing assembly is disposed between the outer wall of the rotating shaft and the rotating sealing limiting member. The first flange edge of the rotating part is fixedly disposed on the circumferential edge of the left end of the rotating shaft. The second flange edge of the rotating part is fixedly disposed on the circumferential edge of the right end of the rotating shaft for fixed sealing connection with the output device.

[0015] In some embodiments, the first retaining ring and the second retaining ring are C-shaped retaining rings.

[0016] The present invention achieves the following technical effects compared to the prior art: This invention provides a microwave rotary joint. A base is fixed to an input device, and a ring-shaped rotating part is coaxially positioned on the right side of the base, forming a choke groove. The rotating part can rotate around its own axis and connect to an output device. A corrugated tube is fitted onto the outer part of the rotating part. The corrugated structure forms a continuous conductive metal channel, ensuring good electromagnetic compatibility during operation. Simultaneously, the corrugated tube covers the opening between the rotating part and the base, utilizing its flexible structure to accommodate the minute radial displacement generated during the rotation of the rotating part, avoiding sealing failure caused by rigid connections. The choke groove formed between the rotating part and the base utilizes the resonant short-circuit effect to form an equivalent electrical contact on the inner wall of the main transmission waveguide, thereby suppressing microwave leakage from the opening between the base and the rotating part. This ensures that microwave signals can be transmitted efficiently along the path of "input device—base—rotating part—output device" with low reflection and low insertion loss. Based on this, by setting at least a portion of the fixed sealing part between the bellows and the rotating part, a rotational sealing connection is formed between the inner wall of the bellows and the outer wall of the rotating part. While the rotating part rotates at high speed relative to the bellows, the gap between the two is reliably sealed, improving the overall sealing performance of the microwave signal transmission path. This allows the transmission channel to maintain a high vacuum environment, effectively reducing the risk of ionization and breakdown of residual gas in the channel under the action of a strong electric field and reducing transmission loss. This overcomes the defect in conventional communication fields where rotating joints cannot meet the vacuum requirements of high-power microwave systems due to insufficient sealing design. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a front view of a microwave rotary joint in some embodiments of the present invention; Figure 2 This is a cross-sectional view of a microwave rotating joint in some embodiments of the present invention; Figure 3 This is a schematic diagram of the base structure in some embodiments of the present invention; Figure 4 This is a cross-sectional view of the base structure in some embodiments of the present invention; Figure 5 This is a schematic diagram of the bellows and fixed sealing part in some embodiments of the present invention; Figure 6 This is a front view of the bellows and the fixed sealing part in some embodiments of the present invention; Figure 7 This is a cross-sectional view of the bellows and the fixed sealing part in some embodiments of the present invention; Figure 8 This is a schematic diagram of the structure of the outer flange of the sealing ring and the rotating sealing limit member in some embodiments of the present invention; Figure 9 This is a cross-sectional view of the outer flange of the sealing ring and the rotating sealing limit member in some embodiments of the present invention; Figure 10 This is a schematic diagram of the rotating part structure in some embodiments of the present invention; Figure 11 This is a cross-sectional view of the rotating part in some embodiments of the present invention; Figure 12 This is a cross-sectional view of a microwave rotating joint in some embodiments of the present invention; Figure 13 This is a diagram showing the internal electric field distribution of a microwave rotary joint in the C-band in some embodiments of the present invention. Figure 14 This is a schematic diagram illustrating the transmission efficiency and reflection performance of a microwave rotary joint in the C-band in some embodiments of the present invention.

[0019] In the diagram: 1-Base; 11-Annular cylindrical tube; 12-First flange edge of base; 121-Third sealing groove; 13-Second flange edge of base; 131-Protruding end; 132-First sealing groove; 133-First stepped structure; 2-Rotating part; 21-Seventh stepped structure; 22-Second mounting groove; 221-Second retaining ring; 23-Rotating shaft; 24-First flange edge of rotating part; 25-Second flange edge of rotating part; 3-Bellower; 31-Third stepped structure; 32-Fourth stepped structure; 4-Fixed sealing part; 41-Fixed part; 42-Outer flange of sealing ring; 421-Second sealing groove; 422- Second-step structure; 43-Rotational sealing limiter; 431-First annular protrusion; 432-First mounting groove; 4321-First retaining ring; 433-Fifth-step structure; 434-Fixed cover; 44-Rotational sealing assembly; 441-First ball bearing; 442-First sealing ring; 443-Conical metal sealing gasket; 444-Second sealing ring; 445-Metal sealing flat gasket; 446-Sealing compression flange; 4461-Sealing edge; 4462-Compression edge; 4463-Sixth-step structure; 447-Second ball bearing; 451-First pad; 452-Second pad; 5-Choke groove. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] The purpose of this invention is to provide a microwave rotary joint to solve the technical problem of insufficient vacuum sealing performance of rotary joints under high-power microwave transmission conditions in the prior art, so as to reliably maintain the high vacuum environment inside the transmission channel and reduce the risk of internal breakdown and transmission loss.

[0022] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] This invention provides a microwave rotary joint, such as Figures 1-13As shown, the device includes a base 1, a rotating part 2, a bellows 3, and a fixed sealing part 4. The base 1 has an annular structure, and its left end is used for a fixed and sealed connection with an input device. The rotating part 2 also has an annular structure and is coaxially disposed at the right end of the base 1. The rotating part 2 can rotate around its own axis, and its right end is used for a fixed and sealed connection with an output device. A gap exists between the left end of the rotating part 2 and the right end of the base 1 to form a choke groove 5. The left end of the bellows 3 is sealed to the right end of the base 1, and the bellows 3 is coaxially sleeved on a portion of the outer side of the rotating part 2. The fixed sealing part 4 is coaxially sleeved on a portion of the outer side of the rotating part 2, and at least a portion of the fixed sealing part 4 is disposed between the bellows 3 and the rotating part 2, so that the inner wall of the bellows 3 and the outer wall of the rotating part 2 are rotatably and sealed together. In microwave applications, by fixing the base 1 to the input device, and coaxially disposing the annular rotating part 2 on the right side of the base 1 and forming a choke groove 5 therewith, the rotating part 2 can rotate around its own axis and connect to the output device. A corrugated tube 3 is fitted onto the outer side of the rotating part 2. Its corrugated structure forms a continuous conductive metal channel, ensuring good electromagnetic compatibility during operation. Simultaneously, the corrugated tube 3 covers the opening between the rotating part 2 and the base 1, utilizing its flexible structure to accommodate the minute radial displacements generated during the rotation of the rotating part, preventing seal failure due to rigid connections. The choke groove formed between the rotating part 2 and the base 1 utilizes the resonant short-circuit effect to create an equivalent electrical contact on the inner wall of the main transmission waveguide, thereby suppressing microwave leakage from the opening between the base and the rotating part. This ensures that microwave signals can be efficiently transmitted along the path of "input device—base—rotating part—output device" with low reflection and low insertion loss. Based on this, by placing at least a portion of the fixed sealing part 4 between the bellows 3 and the rotating part 2, a rotational seal connection is formed between the inner wall of the bellows 3 and the outer wall of the rotating part 2. While the rotating part 2 rotates at high speed relative to the bellows 3, the gap between them is reliably sealed, improving the overall sealing performance of the microwave signal transmission path. This allows the transmission channel to maintain a high vacuum environment, effectively reducing the risk of ionization and breakdown of residual gas under a strong electric field and reducing transmission loss. This overcomes the deficiency of conventional communication fields where rotating joints, due to insufficient sealing design, cannot meet the vacuum requirements of high-power microwave systems. Specifically, the left end in the figure is the end closer to the input device, and the right end is the end closer to the output device. The input device is a microwave input structure relative to the microwave rotating joint, and the output device is also a microwave output structure relative to the microwave rotating joint. The input device specifically includes structures such as a microwave source, and the output device specifically includes structures such as a transmission feeder and a transmitting antenna.

[0024] In some embodiments, the fixed sealing part 4 includes a sealing part and a plurality of fixing parts 41. The outer side of the sealing part is sealed to the right end of the bellows 3, and the inner side of the sealing part is rotatably sealed to a portion of the outer wall of the rotating part 2, so that the inner wall of the bellows 3 and the outer wall of the rotating part 2 are rotatably sealed to each other, ensuring the sealing between the outer wall of the rotating part 2 and the inner wall of the bellows 3 while the rotating part 2 rotates around its own axis. Each fixing part 41 is evenly distributed circumferentially along the outer wall of the bellows 3. The left end of each fixing part 41 is fixedly connected to the right end of the base 1, and the right end of each fixing part 41 is fixedly connected to the outer side of the sealing part, so as to support the axial space of the bellows 3 between the base 1 and the outer side of the sealing part, thereby improving the axial stiffness of the bellows 3 and ensuring the stability of the rotating part 2 when it rotates at high speed around its own axis.

[0025] In some embodiments, the base 1 is a conductor. The base 1 includes an annular columnar tube 11, a first flange edge 12, and a second flange edge 13. The first flange edge 12 is fixedly disposed on the circumferential edge of the left end of the annular columnar tube 11 for fixed and sealed connection with the input device. The second flange edge 13 is fixedly disposed on the circumferential edge of the right end of the annular columnar tube 11 for fixed connection with the left end of the fixing part 41 and abutting against the left end of the bellows 3.

[0026] In some embodiments, the sealing part includes a sealing ring outer flange 42, a rotational sealing limit member 43, and a rotational sealing assembly 44. The rotational sealing limit member 43 is fixedly disposed on the inner side wall of the sealing ring outer flange 42. The rotational sealing assembly 44 is disposed between the inner side of the rotational sealing limit member 43 and a portion of the outer side wall of the rotating part 2, so that the portion of the outer side wall of the rotating part 2 and the rotational sealing limit member 43 are rotated and sealed together, ensuring a high vacuum degree in the microwave signal transmission channel between the rotating part 2 and the sealing part. By fixing the rotational sealing limit member 43 to the inner side wall of the sealing ring outer flange 42 and sleeved on the outer side of the rotational sealing assembly 44, the stability of the rotational sealing assembly 44 is ensured.

[0027] In some embodiments, a protruding end 131 is fixedly provided on the inner side of the second flange edge 13 of the base. The choke groove 5 includes a gap between the protruding end 131 and the left end of the rotating part 2, and a gap recessed to the left on the outer side of the protruding end 131 on the base 1. The length of the choke groove 5 in the axial direction of the base 1 is 1 / 4 of the free space wavelength corresponding to the working frequency. The length of the choke groove 5 in the radial direction of the base 1 is 1 / 4 of the free space wavelength corresponding to the working frequency. The edge of the protruding end 131 is provided with an arc-shaped chamfer. After the leaked microwave enters the choke groove 5, it is reflected at the bottom of the groove. The phase of the reflected wave at the groove opening gap is 180° different from the incident wave, forming a standing wave field to suppress microwave leakage. Furthermore, by opening the choke groove 5 on the right side of the second flange edge 13 of the base, that is, the groove depth direction is parallel to the axial direction of the base 1, the outer diameter of the second flange edge 13 of the base is reduced, making the structure of the base 1 more compact. It should be noted that the choke slot 5 in this application adopts a folded combination design of transmission lines with both radial and axial dimensions of 1 / 4 wavelength. This folds and distributes the traditional choke structure, which extends only in one direction, in both radial and axial directions, making the overall space occupied by the choke slot 5 more uniform in both directions. This effectively reduces the unidirectional occupancy of the choke structure on the axial length and radial dimension of the rotary joint, thus ensuring the overall compactness of the rotary joint and meeting the engineering requirement of avoiding spatial interference between the rotary joint and surrounding components in high-power microwave transmission systems. Furthermore, an electric field homogenization design is adopted at the interface of the two transmission lines. By setting a chamfer structure at this interface, the electric field smoothly transitions in the geometric abrupt region, avoiding excessive concentration of field strength at the interface and the formation of weak points for partial discharge. This effectively increases the upper limit of the power capacity of the rotary joint, enabling it to meet the stringent requirements of device power tolerance under high-power microwave transmission conditions, overcoming the technical limitation of conventional choke slot designs that restrict the overall power level of the system due to field strength concentration.

[0028] In some embodiments, the area where the projection of the left side of the second flange edge 13 of the base onto the axial cross section of the base 1 coincides with the area of ​​the first flange edge 12 of the base is recessed to the right to avoid the fasteners connecting the input device and the first flange edge 12 of the base, while shortening the distance between the first flange edge 12 and the second flange edge 13 of the base, making the structure of the base 1 more compact.

[0029] In some embodiments, an annular first sealing groove 132, coaxial with the base 1, is formed on the right side of the second flange edge 13 of the base. A first stepped structure 133 is also provided inside the first sealing groove 132. A third stepped structure 31, corresponding to the first stepped structure 133, is provided on the left end face of the bellows 3. An annular second sealing groove 421, coaxial with the base 1, is formed on the left side of the outer flange 42 of the sealing ring. A second stepped structure 422 is also provided inside the second sealing groove 421. A fourth stepped structure 32, corresponding to the second stepped structure 422, is provided on the right end face of the bellows 3. A sealing ring is provided in both the first sealing groove 132 and the second sealing groove 421. The first stepped structure 133 on the second flange edge 13 of the base is sealed to the third stepped structure 31 on the bellows 3, and the left end face of the bellows 3 presses against the sealing ring in the first sealing groove 132 so that the left end face of the bellows 3 abuts against the right side face of the second flange edge 13 of the base. The second stepped structure 422 on the outer flange 42 of the sealing ring is sealed to the fourth stepped structure 32 on the bellows 3, and the right end face of the bellows 3 presses against the sealing ring in the second sealing groove 421 so that the right end face of the bellows 3 abuts against the left side face of the outer flange 42 of the sealing ring, thereby ensuring the high vacuum of the microwave signal transmission channel between the bellows 3 and the base 1, and between the bellows 3 and the sealing part.

[0030] In some embodiments, the rotary sealing assembly 44 includes, from left to right, a first ball bearing 441, a first sealing ring 442, a tapered metal sealing gasket 443, a second sealing ring 444, a metal sealing flat gasket 445, a sealing clamping flange 446, and a second ball bearing 447. A first annular protrusion 431 is provided on the inner wall of the rotary sealing limiting member 43, and an annular first mounting groove 432 is formed on the inner wall of the rotary sealing limiting member 43 to the left of the first annular protrusion 431. A first retaining ring 4321 is embedded in the first mounting groove 432, and a first ball bearing 441 is disposed between the first retaining ring 4321 and the first annular protrusion 431; a first sealing ring 442, a conical metal sealing gasket 443, a second sealing ring 444, and a metal sealing flat gasket 445 are all disposed from left to right on the right side of the annular protrusion, and fill the gap between the inner side of the rotational sealing limit member 43 and the outer side wall of the rotating part 2; a fifth stepped structure 433 is also provided on the inner side wall of the rotational sealing limit member 43. Furthermore, the inner diameter on the right side of the fifth step structure 433 is larger than the inner diameter on the left side. The sealing and clamping flange 446 has a sealing edge 4461 and a clamping edge 4462 arranged perpendicularly to each other. There is a sixth step structure 4463 at the connection between the sealing edge 4461 and the clamping edge 4462 of the sealing and clamping flange 446. The sealing edge 4461 of the sealing and clamping flange 446 is fixedly connected to the rotating sealing limit member 43 located on the right side of the fifth step structure 433. The clamping edge 4462 of the sealing and clamping flange 446 is located on the right side. The first sealing ring 442, the conical metal sealing gasket 443, the second sealing ring 444, and the metal sealing flat gasket 445 are tightened. A seventh step structure 21 is provided on the outer wall of the rotating part 2. The outer diameter of the rotating part 2 on the right side of the seventh step structure 21 is smaller than the outer diameter on the left side. An annular second mounting groove 22 is opened on the right side of the seventh step structure 21. A second retaining ring 221 is embedded in the second mounting groove 22. A second ball bearing 447 is disposed between the second retaining ring 221 and the seventh step structure 21.

[0031] In some embodiments, a fixing cover 434 is also fixedly connected to the right end of the rotating sealing limit member 43 to limit the second ball bearing 447 together with the second retaining ring 221.

[0032] By using a first ball bearing 441 and a second ball bearing 447 positioned between the rotating sealing limit member 43 and the outer wall of the rotating part 2, a dual-bearing axis is achieved, ensuring that the base 1 and the rotating part 2 maintain excellent coaxial accuracy during high-speed rotation. It should be noted that by employing a dual-bearing support structure to achieve the rotation function of the rotating part 2, combined with the evenly distributed circumferential fixing parts 41, the coaxial accuracy between the input and output devices during rotation is guaranteed, while simultaneously improving the structural stability and service life of the rotating joint during operation. In particular, the bearing mounting position near the output device uses a bearing with a larger mating size, effectively enhancing the rotating joint's ability to withstand radial forces. Furthermore, this bearing mounting position adopts a quick-change design, allowing for individual bearing replacement without disassembling the entire rotating joint, significantly reducing the manpower and time costs of on-site maintenance and meeting the engineering requirements of high-power microwave systems for equipment maintainability and operational reliability.

[0033] A first sealing ring 442, a tapered metal sealing gasket 443, and a second sealing ring 444 are provided between the first ball bearing 441 and the second ball bearing 447 to achieve a three-stage seal between the rotational sealing limit member 43 and the outer wall of the rotating part 2. The sealing flange 446's pressing edge 4462 is pressed against the metal sealing gasket 445, causing the first sealing ring 442, the tapered metal sealing gasket 443, and the second sealing ring 444 located on the right side of the first annular protrusion 431 to undergo radial deformation, thus filling the gap between the rotational sealing limit member 43 and the outer wall of the rotating part 2. Furthermore, by providing a tapered metal sealing gasket 443 between the first sealing ring 442 and the second sealing ring 444, the tapered metal sealing gasket 443 has a trapezoidal cross-section. Compared to a rectangular cross-section metal sealing gasket, it provides better sealing when compressed by the first sealing rings 442 and 444 on both sides. This design forms a wedge-shaped support, making it less prone to extrusion failure even under the large axial clamping force of the sealing and clamping flange 446. Furthermore, when the sealing edge 4461 of the sealing and clamping flange 446 is fixedly connected to the rotating sealing limit member 42 at the right side of the fifth step structure 433, the fifth step structure 433 and the sixth step structure 4463 abut against each other, improving the sealing performance between the rotating sealing limit member 43 and the sealing and clamping flange 446. Furthermore, as the first sealing ring 442 or the second sealing ring 444 ages, the sealing and clamping flange 446 can be adjusted to the left, keeping the clamping edge 4462 of the sealing and clamping flange 446 in a tight state against the first sealing ring 442, the conical metal sealing gasket 443, the second sealing ring 444, and the metal sealing flat gasket 445, until the sixth step structure 4463 of the sealing and clamping flange 446 and the right side of the fifth step structure 433 on the inner wall of the rotating sealing limit member 43 are sealed together. It should be noted that by configuring a multi-redundant sealing structure consisting of sealing rings and sealing gaskets in the fixed sealing part 4, a combined sealing scheme ensures that the internal channel of the waveguide can maintain a stable high vacuum environment during high-speed rotation. This improves the reliability of vacuum maintenance and extends the maintenance-free cycle, overcoming the technical limitations of conventional communication fields where the vacuum sealing performance of rotating joints deteriorates rapidly under long-term operation, making it difficult to continuously meet the requirements of high-power microwave transmission. Compared with the existing magnetohydrodynamic sealing technology, the sealing form using a first sealing ring 442, a conical metal sealing gasket 443, a second sealing ring 444, a metal sealing flat gasket 445, and a sealing compression flange 446 is better able to adapt to the temperature changes of the rotating part 2 during high-speed rotation, avoiding sealing failure caused by drastic temperature differences. Furthermore, it can maintain the stability of the seal even when the base 1 is installed in a frequently vibrating environment, and is less prone to sealing failure due to magnetohydrodynamic leakage.

[0034] In some embodiments, the fixed sealing part 4 further includes a plurality of first gaskets 451 and a plurality of second gaskets 452. Each first gasket 451 is evenly distributed circumferentially along the outer side wall of the bellows 3. Each first gasket 451 is fixedly connected to the second flange edge 13 of the base to press the left end face of the bellows 3 against the first sealing groove 132 and the first stepped structure 133 on the right side surface of the second flange edge 13 of the base. Each second gasket 452 is evenly distributed circumferentially along the outer side wall of the bellows 3. Each second gasket 452 is fixedly connected to the outer flange 42 of the sealing ring to press the right end face of the bellows 3 against the second sealing groove 421 and the second stepped structure 422 on the left side surface of the outer flange 42 of the sealing ring, so as to ensure the high vacuum degree of the microwave signal transmission channel between the bellows 3 and the base 1, and between the bellows 3 and the sealing part.

[0035] In some embodiments, the rotating part 2 includes a rotating shaft 23, a first flange edge 24, and a second flange edge 25. The rotating shaft 23 is hollow, and the rotational sealing assembly 44 is disposed between the outer wall of the rotating shaft 23 and the rotational sealing limiting member 43. The first flange edge 24 is fixedly disposed on the circumferential edge of the left end of the rotating shaft 23, and the first flange edge 24 can prevent the rotating part 2 from coming out of the sealing part when rotating around its own axis. The second flange edge 25 is fixedly disposed on the circumferential edge of the right end of the rotating shaft 23 for fixed sealing connection with the output device.

[0036] In some embodiments, the first retaining ring 4321 and the second retaining ring 221 are C-shaped retaining rings, so as to facilitate the first retaining ring 4321 and the second retaining ring 221 being respectively fitted into the first mounting groove 432 and the second mounting groove 22.

[0037] In some embodiments, an annular third sealing groove 121 coaxial with the base 1 is provided on the left side of the first flange edge 12 of the base, which is used to fix and seal the connection with the input device to ensure the vacuum degree of the microwave signal transmission channel between the input device and the base 1.

[0038] Preferably, the annular cylindrical tube 11, the first flange edge 12, and the second flange edge 13 of the base 1 are integrally formed, and the outer flange 42 of the sealing ring and the rotating sealing limit member 43 of the sealing part are integrally formed. During installation, the following steps are included: The rotating sealing limit member 43 is sleeved on the outer side of the left end of the rotating shaft 23, and the first ball bearing 441 is sleeved from the left end between the rotating shaft 23 and the rotating sealing limit member 43 and set on the left side of the first annular protrusion 431. Then the first retaining ring 4321 is embedded in the first mounting groove 432 to limit the first ball bearing 441. Next, the first sealing ring 442, the conical metal sealing gasket 443, the second sealing ring 444, and the metal sealing flat gasket 445 are sequentially inserted from the right end between the rotating shaft 23 and the rotating sealing limit member 43, and positioned on the right side of the first annular protrusion 431. Then, the sealing edge 4461 of the sealing compression flange 446 is fixedly connected to the right side of the fifth step structure 433, so that the compression edge 4462 of the sealing compression flange 446 presses against the first sealing ring 442, the conical metal sealing gasket 443, the second sealing ring 444, and the metal sealing flat gasket 445. The second ball bearing 447 is inserted from the right end between the rotating shaft 23 and the rotating seal limiting member 43 and fitted into the right side of the seventh step structure 21. Then the second retaining ring 221 is inserted from the right end between the rotating shaft 23 and the rotating seal limiting member 43 and fitted into the second mounting groove 22 to limit the second ball bearing 447. The first flange edge 24 of the rotating part is installed from the left side of the rotating shaft 23 using an interference fit. Take the base 1, and install the O-ring seal in the first sealing groove 132 on the base 1 and the second sealing groove 421 on the outer flange 42 of the sealing ring. Place the bellows 3 between the second flange edge 13 of the base and the outer flange 42 of the sealing ring, and fix it to the second flange edge 13 of the base through the first pad 451 to press the left end face of the bellows 3 against the first sealing groove 132 and the first stepped structure 133. Fix it to the outer flange 42 of the sealing ring through the second pad 452 to press the right end face of the bellows 3 against the second sealing groove 421 and the second stepped structure 422. The left end of the fixing part 41 is fixedly connected to the second flange edge 13 of the base, and the right end is fixedly connected to the outer flange 42 of the sealing ring, so as to support the axial space between the base 1 and the outer side of the sealing part where the bellows 3 is provided. An O-ring is installed in the third sealing groove to fix and seal the first flange edge 12 of the base to the input device, and fix and seal the second flange edge 25 of the rotating part to the output device.

[0039] Taking a microwave rotary joint operating in the C-band as an example, the model of this embodiment is established and the parameters are set in the full-wave electromagnetic simulation software. The simulation results of the internal electric field distribution and reflection and transmission performance of the device are obtained.

[0040] like Figure 13 As shown, this is an example with input power. P in This is a diagram showing the internal electric field distribution at 0.5W. The left side shows the electric field distribution of the example, and the right side shows the electric field intensity diagram, including the maximum electric field intensity. E max The value is 362 V / m, taken as the breakdown threshold of metals in vacuum. E br=50 MV / m for evaluation, according to the formula P c = P in ( E br / E max The power capacity of the embodiment can be obtained by calculation using )^2. P c With a capacity exceeding 9.53GW, the device demonstrates excellent power handling capability.

[0041] like Figure 14 As shown, in this embodiment, the simulated transmission efficiency is better than 97.5% in the 4.02~4.97 GHz frequency band, and the reflection coefficient S11 remains less than -20dB, corresponding to a fractional bandwidth of 21.11%, demonstrating the device's good transmission performance and impedance matching characteristics.

[0042] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A microwave rotary joint, characterized in that: include The base has a ring-shaped structure, and the left end of the base is used for a fixed and sealed connection with the input device; The rotating part has a ring structure and is coaxially disposed at the right end of the base. The rotating part can rotate around its own axis. The right end of the rotating part is used for fixed and sealed connection with the output device. There is a gap between the left end of the rotating part and the right end of the base to form a choke groove. A bellows, the left end of which is sealed to the right end of the base, and the bellows is coaxially sleeved on the outer side of a portion of the rotating part; and A fixed sealing part is provided, which is sealed to the right end of the bellows. The fixed sealing part is coaxially sleeved on the outside of the rotating part. At least a portion of the fixed sealing part is disposed between the bellows and the rotating part, so that the inner wall of the bellows and the outer wall of the rotating part are rotatably sealed together.

2. The microwave rotary joint according to claim 1, characterized in that, The fixed sealing part includes: A sealing part, the outer side of which is sealingly connected to the right end of the bellows, and the inner side of which is rotatably sealingly connected to a portion of the outer wall of the rotating part; and Multiple fixing parts are provided, each of which is evenly distributed circumferentially along the outer side wall of the bellows. The left end of each fixing part is fixedly connected to the right end of the base, and the right end of each fixing part is fixedly connected to the outer side of the sealing part, so as to support the axial space of the bellows provided between the outer side of the base and the sealing part.

3. The microwave rotary joint according to claim 2, characterized in that, The base is a conductor, and the base includes: Annular cylindrical tube; A first flange edge of the base, the first flange edge of the base being fixedly disposed on the circumferential edge of the left end of the annular cylindrical tube, for a fixed and sealed connection with the input device; and The second flange edge of the base is fixedly disposed on the circumferential edge of the right end of the annular columnar tube and is used to fixally connect with the left end of each of the fixing parts.

4. The microwave rotary joint according to claim 3, characterized in that, The sealing part includes: The outer flange of the sealing ring has the right end of the fixing part fixedly connected to the outer ring of the outer flange of the sealing ring, and the right end of the bellows abuts against the inner ring of the outer flange of the sealing ring. A rotating sealing limiter, the rotating sealing limiter being fixedly disposed on the inner side wall of the outer flange of the sealing ring; and A rotary sealing assembly is disposed between the inner side of the rotary sealing limit member and a portion of the outer side wall of the rotating part, so that the portion of the outer side wall of the rotating part and the rotary sealing limit member are rotary sealed together.

5. The microwave rotary joint according to claim 4, characterized in that, A protruding end is fixedly provided on the inner side of the second flange edge of the base. The choke groove includes a gap between the protruding end and the left end of the rotating part, and a gap recessed to the left on the outer side of the protruding end on the base. The length of the choke groove in the axial direction of the base is 1 / 4 of the free space wavelength corresponding to the working frequency. The length of the choke groove in the radial direction of the base is 1 / 4 of the free space wavelength corresponding to the working frequency. The edge of the protruding end is provided with an arc-shaped chamfer.

6. The microwave rotary joint according to claim 4, characterized in that, An annular first sealing groove, coaxial with the base, is formed on the right side of the second flange edge of the base. A first stepped structure is also provided inside the first sealing groove. A third stepped structure, corresponding to the first stepped structure, is provided on the left end face of the bellows. An annular second sealing groove, coaxial with the base, is formed on the left side of the outer flange of the sealing ring. A second stepped structure is also provided inside the second sealing groove. A fourth stepped structure, corresponding to the second stepped structure, is provided on the right end face of the bellows. A sealing ring is provided in both the first and second sealing grooves. The sealing ring is formed by the first stepped structure on the second flange of the base sealing ring and the third stepped structure on the bellows sealing ring, with the left end face of the bellows pressing against the sealing ring in the first sealing groove, so that the left end face of the bellows abuts against the right side of the second flange of the base sealing ring sealing ring. The second stepped structure on the outer flange of the sealing ring sealing ring and the fourth stepped structure on the bellows sealing ring sealing ring, with the right end face of the bellows pressing against the sealing ring in the second sealing groove, so that the right end face of the bellows abuts against the left side of the outer flange of the sealing ring sealing ring sealing ring.

7. The microwave rotary joint according to claim 6, characterized in that, The rotary sealing assembly comprises, from left to right, the following components arranged sequentially: The first ball bearing has a first annular protrusion on the inner wall of the rotating sealing limit member, and an annular first mounting groove is formed on the inner wall of the rotating sealing limit member to the left of the first annular protrusion. A first retaining ring is embedded in the first mounting groove, and the first ball bearing is disposed between the first retaining ring and the first annular protrusion. A first sealing ring, a conical metal sealing gasket, a second sealing ring, and a metal sealing flat gasket are provided from left to right on the right side of the annular protrusion, and fill the gap between the inner side of the rotating sealing limit member and the outer side wall of the rotating part. The sealing and pressing flange has a fifth step structure on the inner wall of the rotating sealing limit member, and the inner diameter of the right side of the fifth step structure is larger than the inner diameter of the left side. The sealing and pressing flange has a sealing edge and a pressing edge arranged perpendicularly to each other. A sixth step structure is provided at the connection between the sealing edge and the pressing edge of the sealing and pressing flange. The sealing edge of the sealing and pressing flange is fixedly connected to the rotating sealing limit member at the right side of the fifth step structure. The pressing edge of the sealing and pressing flange presses against the first sealing ring, the conical metal sealing gasket, the second sealing ring and the metal sealing flat gasket from the right side. The sixth step structure of the sealing and pressing flange can seal and cooperate with the right side of the fifth step structure on the inner wall of the rotating sealing limit member. as well as The second ball bearing has a seventh-step structure on the outer wall of the rotating part. The outer diameter of the rotating part on the right side of the seventh-step structure is smaller than that on the left side. An annular second mounting groove is formed on the outer wall of the rotating part on the right side of the seventh-step structure. A second retaining ring is embedded in the second mounting groove. The second ball bearing is disposed between the second retaining ring and the second annular protrusion.

8. The microwave rotary joint according to claim 7, characterized in that, The fixed sealing part further includes: A plurality of first gaskets are evenly distributed circumferentially along the outer side wall of the bellows. Each first gasket is fixedly connected to the second flange edge of the base to press the left end face of the bellows against the first sealing groove and the first stepped structure on the right side surface of the second flange edge of the base; and Multiple second gaskets are evenly distributed circumferentially along the outer side wall of the bellows. Each second gasket is fixedly connected to the outer flange of the sealing ring to press the right end face of the bellows against the second sealing groove and the second stepped structure on the left side face of the outer flange of the sealing ring.

9. The microwave rotary joint according to claim 8, characterized in that, The rotating part includes: A rotating shaft, which is hollow, and all rotating sealing assemblies are disposed between the outer wall of the rotating shaft and the rotating sealing limiting member; The first flange edge of the rotating part is fixedly disposed on the circumferential edge of the left end of the rotating shaft; and The second flange edge of the rotating part is fixedly disposed on the circumferential edge of the right end of the rotating shaft and is used for a fixed and sealed connection with the output device.

10. The microwave rotary joint according to claim 7, characterized in that, The first retaining ring and the second retaining ring are C-shaped retaining rings.

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