JPS62246228A - Coaxial waveguide structure - Google Patents

Abstract

PURPOSE:To blow a cooling air directly to the surface of a dielectric airtight window plate, by delivering the cooling air through air holes furnished at the bottom of a ring-form adjustment groove close to the said window plate. CONSTITUTION:A cooling air is led in or exhausted through air holes 64, 76, and 84a formed at the bottom of a ring-form adjustment groove C close to a dielectric airtight window plate 34. Therefore, the cooling wind is blown to the surface of the dielectric airtight window plate 34 securely. Consequently, as well as the cooling function of the dielectric airtight window plate 34 is improved, a leakage of highfrequency waves through a cooling air inlet hole 83 and exhaust hole 98 can be restricted effectively.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a coaxial waveguide structure equipped with a dielectric hermetic window plate, which is applied to the output section of a microwave electron tube such as a Talistron. Regarding.

(Prior art) The structure of the output section of a microwave electron tube such as a klystron is a coaxial/rectangular waveguide conversion in which a coaxial waveguide is connected to the output center and a rectangular waveguide is connected to the tip of the coaxial waveguide. Some are equipped with a container. And at the tip of the coaxial waveguide structure,
An airtight window plate made of ceramic dielectric material called an airtight window is provided in a vacuum-tight manner.

An example of a schematic configuration of a straight beam type multi-air conditioning klystron having such a coaxial waveguide structure will be explained with reference to FIG.

The talistron main body includes an intermediate resonant cavity 11, a drift tube 12, an output cavity 13, and a collector section 14, which are part of the main body and are arranged in a vertical line along the tube axis. A waveguide structure constituting an output section is hermetically connected to a part of the cavity wall of the output cavity 13. This interaxial waveguide structure has an inner conductor 1G and an outer conductor 11, and the inner conductor 1
As shown by arrow Q at 6, cooling water is also circulated through the outer conductor (not shown). The diameter of both the inner and outer conductors is enlarged from the middle, and the inner conductor has a large diameter part 1.
8 and an outer conductor with a large diameter portion 19, and a dielectric airtight window plate 20 is vacuum-tightly joined between both conductors at these large diameter portions. Both conductors are divided in the axial direction on the part at divisions 8I118a and 19a which are inward from the position of the airtight window plate 20, and both conductors are arced at this part) 8f
8, etc., and are integrally connected electrically and vacuum-tightly. The tip of this coaxial waveguide structure is connected to a rectangular waveguide 21. That is, the tip flange portion of the large diameter outer conductor portion 19 is connected to the opening portion of the wide surface 22 of the rectangular waveguide 21,
Further, the tip end 18b of the large-diameter inner conductor portion 18 is electrically and mechanically connected to the opposing wide surface 24 of the rectangular waveguide via the doorknob-shaped extension portion 23. Note that the open flange 25 of the output waveguide is connected to an external load circuit.

(Problems to be Solved by the Invention) This type of coaxial waveguide structure, especially for ultra-high power applications, has a tR dielectric airtight window plate that has an airtight joint between the inside and outside and the atmosphere side of the airtight window plate, as described above. The structure is such that the surface is cooled from the outside. In order to prevent the dielectric airtight window plate from being destroyed by multipactor discharge, its inner surface is coated with a coating layer for preventing discharge. As described above, it is necessary to effectively cool the dielectric airtight window plate to maintain stable operation. Therefore, a structure is also known in which another dielectric plate is arranged close to the M electric airtight window plate at a distance, and cooling air is introduced and discharged between the dielectric plates.

However, the ventilation holes for introducing and discharging cooling air between both dielectric plates are usually formed as close to the window plate as possible so that the cooling air can be blown directly onto the surface of the airtight window plate. be. However, since annular cooling chambers for water cooling are provided on the inner and outer peripheries of the airtight window plate, forming ventilation holes there would make the structure extremely complicated.

If the ventilation holes are placed in a position that avoids this cooling chamber, the cooling air introduction and exhaust holes will be far away from the surface of the dielectric airtight window plate that is to be cooled, making it difficult for the cooling air to directly hit the surface of the airtight window plate. Become. Further, the cooling air introduction and exhaust holes may impair high frequency transmission characteristics, and there is also a risk that high frequency waves may leak to the outside.

An object of the present invention is to eliminate the above-mentioned disadvantages and to provide a coaxial waveguide structure configured so that cooling air can be blown directly onto the surface of a dielectric airtight window plate.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a thin cylinder of at least one of an inner conductor and an outer conductor that is hermetically joined to a dielectric airtight window plate, and a thin cylinder near the airtight window plate together with the conductor. Conductor cylindrical portions forming matching annular grooves for high frequency matching are provided at predetermined intervals to protrude toward the airtight window plate, and vent holes are provided in the inner part of the matching annular grooves. This is a coaxial waveguide structure configured to allow cooling air to be blown through the coaxial waveguide structure.

(Function) According to the present invention, cooling air is guided through the alignment annular groove provided close to the dielectric airtight plate and the ventilation hole formed in the inner part thereof, and Reliably sprays onto the surface. Therefore, even if an annular water-cooling chamber is provided on the atmosphere side of the inner or outer circumference of the thin cylinder, there is no restriction on the structure for introducing or discharging the cooling air. The cooling effect of the dielectric airtight plate is improved, and leakage of high frequency waves from the through holes for introducing and discharging cooling air can be effectively suppressed. This also allows the through holes for introducing and discharging cooling air to be relatively large in size, thereby making it possible to further increase the amount of cooling air introduced.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

Identical parts are designated by the same reference numerals.

An example in which the present invention is applied to a beam rectilinear multi-cavity klystron will be explained with reference to FIGS. 1 to 6.

An output rectangular waveguide structure carrier is vacuum-tightly connected to an output cavity of a klystron main body (not shown).

The waveguide structure carrier has an airtight window structure mosquito in a part thereof. That is, the ceramic vt? ! An airtight window plate 34 made of a body is vacuum-tightly joined. Further, a dielectric partition disk 35 is mechanically fitted and fixed near the airtight window plate 34 on the atmosphere side. The outer extension 36 of the inner conductor on the atmosphere side is electrically connected to a doorknob-shaped extension 37 formed of a thin conductive plate shaped into a bowl shape. This doorknob-like extension 37 is electrically and mechanically connected to one wide side 39 of the output rectangular waveguide 38 . The inner conductor extension part 36 is configured so that cooling water can be circulated therein as shown by arrow P. The tip 7 flange 40 of the large-diameter outer conductor portion 33 is connected to the other wide surface 41 of the rectangular waveguide through a hole therebetween. Inner conductor outward extension 31 on the vacuum fr4Wi side
a1 and outer conductor outward extension 32a are coupled to the output air conditioner as described above. Both conductors are configured so that cooling water can be circulated inside each conductor as shown by arrow Q. In this way, a converting section from a coaxial waveguide to a rectangular waveguide at the output section of the klystron is constructed.

Next, the structure of each part will be explained according to the preferred assembly order.

Inner and outer conductor outward extensions 31a constituting the coaxial waveguide structure
, 32a each have a bottomed cylindrical portion 4 with a large diameter inner conductor made of copper.
2, an outer conductor funnel-shaped portion 43 having a tapered inner surface, and an outer first alignment cylinder 44 having a large diameter portion of the outer conductor. The inner conductor bottomed cylindrical portion 42 has an inner first matching circle 1118B4.
5 and a three-stage recess 46.41.4 on the inside.
It has 8. A stepped reinforcing disk 49 made of a material with high mechanical strength such as stainless steel is fitted into the bottom portion 48 . The inner conductor bottomed cylindrical portion 42 also has a minute ventilation hole 50 in its side wall, and a female screw portion 51 for positioning bored in a part of the outer periphery. The first outer aligning cylinder 44 has an aligning cylindrical portion 52 at the tip, and a fixing flange 53 and an airtight sealing flange 54 made of thin stainless steel are joined to the outer periphery. Fixing flange 53
A plurality of tightening bolts 55 are inserted into the holder. A through hole 57 for inserting a positioning tool 56 is formed in a portion of the outer conductor funnel-shaped portion 43 and the cylinder 44 .

The ends of the structure of the outer extension portion of the inner and outer conductors are integrally fixed to the output cavity of the Talistron.

On the other hand, there is a concave airtight window structure having a dielectric airtight window plate 34.

is assembled separately as follows.

That is, a thin cylinder 61 is hermetically sealed to the outer peripheral surface of a dielectric airtight window plate 34 made of ceramic, and a cooling jacket cylinder 6 forms an annular cold W chamber 62 for water cooling on the outer periphery.
3 are joined. Cooling water can be introduced into and discharged from the outside into the annular cooling chamber 62 as shown by arrow R. Also, at the end of the cylinder 63 on the atmosphere side, there is ? ! @ 1i of micro ventilation holes 64! It is formed in an i-radial shape, and an airtight arrival flange 65 made of thin stainless steel is joined to the outer periphery of the end on the vacuum side. A plurality of female screw holes 63a are formed in the upper end surface of the cylindrical body 63, and a fixing ring 63b is fitted around the outer periphery and is secured to the bulge 63c. A thin cylinder 66 as an inner conductor is hermetically soldered to the inner peripheral surface of the center hole of the dielectric airtight window plate 34, and a ring for connecting the inner conductor is similarly formed on the inner periphery to form an annular cooling chamber 67 for water cooling. 68 and inner cylinder 69 are fixed. The inner conductor connecting ring 68 has an outer circumferential diameter Db that is slightly larger than the inner diameter dimension Da of the stepped inner circumferential wall 47a of the inner conductor bottomed cylindrical portion 42 in a component state. Further, this has a female threaded hole 70 in the center, and the opening thereof is vacuum-tightly closed by a thin airtight bulkhead plate 11 made of copper. In this way, the ring 68 constitutes a hermetically closed portion of the inner conductor section that is sealed to the dielectric hermetic window plate. As a result, the inner region of the outer conductor portion of the airtight window structure is vacuum-tightly closed by the dielectric airtight window plate 34 and the inner conductor connecting ring 68 having an airtight closing portion.

In the inner cylinder 69, a plurality of sets of through holes 72, 73 for circulating cooling water into the cooling chamber 61 are formed radially corresponding to both ends of the cooling chamber. Further, a second inner matching cylindrical member 75 made of copper and having an inner matching cylindrical portion 74 is connected to the upper end of the inner cylinder 69 .

The alignment cylindrical portion 74 surrounds the thin cylinder 66 at a predetermined interval, and has a distal end extending to the vicinity of the airtight window plate. Further, a plurality of ventilation holes 16 parallel to the axial direction are formed at the bottom thereof. Note that a coating layer (not shown) for preventing multipactors is applied to the inner surface of the dielectric airtight window plate 34.

As mentioned above, this airtight window structure can be assembled by itself. In this way, the airtight window structure, including the part of the dielectric airtight window plate that is airtightly joined between the inner and outer conductors, can be assembled independently from the tube body, making these airtight joints extremely reliable. A high bonding structure can be easily achieved.

In particular, the formation of airtight joints on the inner and outer peripheral surfaces of the dielectric airtight window plate and the application of the multipactor prevention coating layer can be easily made extremely reliable.

Now, the airtight window structure thus prepared is connected to the ends of the inner and outer conductor extensions extending from the output air conditioner in the following manner. That is, first, a small electric heating furnace 77 capable of local heating is placed over the inner conductor bottomed cylindrical portion 42 to locally heat the cylindrical portion. In addition, in order to maintain accurate concentric positions of the inner conductor and outer conductor, a positioning jig 56 is screwed between them.
Leave it at V. Then, while the cylindrical part 42 reaches a predetermined temperature and is thermally expanded, the electric heating furnace is immediately removed, and the airtight window structure is adjusted to match that of the inner conductor connecting ring 6.
Step inner circumferential wall 4 of cylindrical portion 42 thermally expanding the tip end of 8
Insert or press fit into 7a. Thereafter, when the inner conductor is cooled to room temperature, the connecting ring 68 and the cylindrical portion 42 of the inner conductor are mechanically and electrically coupled to each other in a tight fit state by shrink fitting. The joint portion resulting from this close fitting by shrink blowing is marked with a code length of -.

In this state, since the Ugetsu wearing flanges 54 and 65 on the outer conductor side conform to the gassho structure, their entire circumferences are hermetically welded by arc welding. Further, the fixing flanges 53.63b are tightened and fixed by bolts 55.

In this way, the outer conductor large diameter portions 33 are vacuum-tightly connected to each other, and the outer conductor cylinders 44 and 63 are electrically press-connected. After the two have been connected, the positioning jig 56 is removed,
The through hole 51 is vacuum-tightly sealed by a sealing member 78.

By assembling in this manner, the inner first matching cylinder portion 45 is positioned at a predetermined slight interval on the outer periphery of the thin cylinder 66 of the inner conductor joined to the dielectric airtight window plate 34. This inner first alignment cylindrical part 45, and a second alignment cylindrical part 74 on the atmosphere side that closely opposes this with an airtight window plate in between.
, and the conductor wall including the thin circle WiBB, together with an annular groove for matching on the outer conductor side described later, eliminates impedance discontinuity near the dielectric airtight window plate to obtain high frequency matching so that electromagnetic wave reflection does not occur. It constitutes an annular groove C for alignment. Both closely opposing alignment cylinders 45 and 74 also connect the thin-walled cylinder 66 and the airtight window plate 34 to the airtight soldered portion at the 'lS frequency i! It also acts as a shield from magnetic fields. The airtight soldered joint between the airtight window plate 34 and the thin cylinder 6G is located approximately inside this annular groove C, and almost no high frequency current flows therethrough, thereby protecting the joint. Further, since the joint portion connected by shrink fitting is also located at the inner part of the matching annular groove C, no high frequency current flows there, and the reliability of the mechanical and electrical connection is maintained high. In this way, the inner conductor is integrally connected to each other by shrink fitting and the outer conductor is subsequently welded.

Next, on the cooling jacket cylindrical body 63, a partition plate holding ring 80 having a second outer matching cylinder part 79 and forming a part of the outer conductor part is attached, and a fixing bolt 81 is inserted into the female screw hole 63a.
The connection is fixed by screwing into the

Then, on the inner step 80a of this ring 80 and the step 81175a of the inner second alignment cylindrical member 75 of the inner conductor,
The center hole 35a of the partition disk 35 made of a dielectric material with low high frequency loss such as Teflon (trade name) is fitted.

This partition wall disk 35 prevents the cooling air from escaping, and the airtight window plate 3
This is to ensure that the entire surface of the atmosphere side of the conductor 4 is fully touched, and to increase the mechanical holding strength of the inner conductor and outer conductor. On the surface of this partition disk 35, a circumference W482 for improving high-frequency withstand voltage is coaxially formed with I! Several holes are formed, and a relatively small through hole 83 for monitoring the airtight window plate is formed in a part. The seven outer matching cylindrical parts 52 and the thin-walled cylinder 61 constitute an annular matching groove C for high frequency matching near the dielectric airtight window plate, as described above. Both alignment cylindrical parts 79.5
2. Similarly, it acts to shield the airtight soldered joint between the thin cylinder 61 and the airtight window plate 34 from high frequency electromagnetic fields. As a result, the outer thin-walled cylinder 61 and each contact portion of the outer conductor are located inside this matching annular groove C, so that almost no high-frequency Wi current flows there, and high reliability of each joint is maintained. drooping

Furthermore, a refrigerant guide member 84 for guiding cooling water and cooling air is placed on the O-ring 8 on the inner second matching cylindrical member 75.
Connect via 5. This refrigerant guide member 84 has a substantially cylindrical shape, and has four through holes 848 for cooling water passages arranged in parallel in the axial direction, and four through holes 848 for cooling water passages radially at positions offset from the holes in the circumferential direction. Holes 84b are formed alternately. A cylinder 86 constituting the outwardly extending portion 36 of the inner conductor and a partition wall cylinder 87 for a refrigerant passage inside the cylinder 86 are soldered to this refrigerant guide member 84 . These cylinders have upper end flanges 88,89
are joined. The doorknob-shaped extension 37 is connected and fixed to the upper end flange 88 with bolts 90 . Furthermore, inside the hollow inner conductor part, a vibe 91a for guiding cold water,
91b is inserted into the center hole of the cylinder 69 and fixed liquid-tightly.

A vibe 92a for blowing cooling air is attached to the flange 89, and a hose 92b for introducing cooling water is attached to the inner guide pipe 91a.
However, a drainage hose 92c is further connected to the flange 89 and extends outside the waveguide. Note that these are pillars 9
3, it is mechanically held and fixed to the support plate 94.

In this way, during operation, the cooling water flows from the cooling water introduction hose 92b to the inner guide vibrator 91a, as shown by arrow P.
91b, and is introduced into the annular cooling chamber 67 of the inner conductor through one of the through holes 12 formed in the inner circle IPI 169. Then, it passes through the outer periphery of the vibrator from the other through hole 73, passes through the radial through hole 84b of the refrigerant guide member 84, and then enters both cylinders 8.
6.87 and drained from the drainage hose 92c. In this way, the cooling water can circulate and cool each part of the inner conductor.

In addition, as shown by the dotted arrow S, the cooling air is passed from the blowing vibrator 92a through the space between the vibrator 91a and the cylinder 87, and then through the axial ventilation hole 84a formed in the guide member 84 for the second alignment of the inner conductor. The air is sprayed from the ventilation hole 76 formed in the cylindrical member 15 through the alignment annular groove C to the atmospheric side surface of the airtight window plate 34. In addition, the cooling air flows through two dielectric disks 3.
Escape to the outside is almost suppressed by the cavity T defined by 4.35, and it advances toward the outer conductor side along the surface of the airtight window plate.

Then, it passes through the matching ring 1IIC on the outer conductor side and is discharged to the outside from the ventilation hole 64 formed in the inner part thereof. In this way, from the ventilation hole formed in the inner part of the matching annular groove C on the inner conductor side, the cold fJII is passed through this annular groove C.
! 1 can be sprayed onto the atmosphere side surface of the airtight window plate 34.

These ventilation holes 76 formed in the inner conductor part and the outer conductor part
．． 64 not only have dimensions that block IX frequencies, but also are located inside the matching annular groove, so as mentioned above, high frequency leakage from these vent holes to the outside is ensured. Deterred.

Furthermore, since these ventilation holes are formed at positions necessarily avoiding the annular cooling chambers 62, 61 of the inner and outer conductors, they do not interfere with the configuration of the cooling chambers. As in the actual example described above, if the cooling air is first blown around the inner circumference of the airtight window plate through the ventilation holes and annular groove on the inner conductor side, the area near the inner conductor of the airtight window plate will be relatively The high-frequency electric field is high and the temperature tends to rise particularly in this area, but this can be effectively cooled down.

Note that it is also sufficiently practical to introduce the cooling air through the ventilation hole on the outer conductor side and exhaust it through the ventilation hole on the inner conductor side.

Furthermore, the annular groove C1 cold W for alignment of the inner conductor and outer conductor
The chambers B2 and 67 and the ventilation holes 76 and 64 may be formed either inside or outside. That is, at least on the side where the annular cooling chamber for water cooling is formed on the atmosphere side of the thin-walled cylinder of the inner and outer conductors, an annular matching groove is formed, and a ventilation hole for introducing or discharging cooling air is provided in the inner part of the annular groove.

On the conductor side where the cooling chamber for water cooling is not installed, a ventilation hole may be formed near the airtight window plate or at a position separated from the airtight window plate.

In that case, the ventilation holes should have high frequency cross-sectional dimensions.

On the outer conductor side, a conductor is attached to the partition plate holding ring 80!
A flange 40 is connected and fixed by a bolt 96 via a 110 ring 95, and this 7 flange 40 is connected to a rectangular waveguide 38.
It is fixed integrally. The waveguide 38 is provided with a connection flange 97 for connection to an external load circuit.

In addition, a through hole 98 having a high frequency blocking size is provided in a part of the doorknob-shaped extension. Thereby, the temperature of the dielectric airtight window plate 34 or the presence or absence of high frequency arc discharge in the vicinity can be detected through the through hole 98 and the small through hole 83 formed in the dielectric partition disk 35. For that purpose, a sensor device 99 for concentration or arc detection, etc.
is the inner cavity r of the thin conductor plate that constitutes the doorknob-shaped extension.
/! It is stored in UU. Of course, the sensor device may be provided outside the waveguide, or may be attached and used only when monitoring is necessary.

The present invention can be applied not only to a high-frequency coupling section between a coaxial waveguide and a rectangular waveguide, but also to a wide variety of coaxial waveguide structures including an inner conductor, an outer conductor, and an airtight window structure. can.

[Effects of the Invention] As explained above, according to the present invention, cooling air is introduced or exhausted through the ventilation hole formed in the inner part of the matching annular groove adjacent to the dielectric airtight window plate. Therefore, the cold l1ll is reliably sprayed onto the surface of the dielectric airtight window plate. Therefore, the cooling effect of the dielectric airtight window plate is improved, and leakage of high frequency waves from the through holes for introducing and discharging cooling air can be effectively suppressed. Further, there is no hindrance to providing an annular cooling chamber for water cooling with an airtight window plate on at least one of the inner and outer conductors. Thereby, the airtight window plate can be water-cooled and air-cooled with a relatively simple structure. The present invention is particularly suitable for a circumferential waveguide structure for large continuous wave transmission such as IMW or more.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention, FIG. 2 is an exploded sectional view of its main parts, and FIG. 3 is a top view of its main parts.
4 is a cross-sectional view of the main parts, FIG. 5 is a perspective view of the main parts, and FIG. 6 is an enlarged sectional view of the main parts of the present invention.
FIG. 7 is a schematic diagram illustrating a conventional structure. Carrier... Circumferential waveguide structure, 31... Inner conductor, 32...
- Outer conductor, 34... Dielectric airtight window plate, 35... Dielectric partition plate,... Airtight window structure, 62゛, 67...
Cooling chamber for water cooling, C...Annular groove for matching, 74.19...
・Cylinder for alignment, 64.7G, 84a...Cooling air vent, S...Flow direction of cooling air. Applicant's agent Patent attorney Takehiko Suzue Figure 3 Figure 4

Claims (2)

[Claims] (1) A dielectric airtight window plate is vacuum-tightly sealed between each thin-walled cylinder of the inner conductor and outer conductor constituting the coaxial line, and a cooling chamber for water cooling is provided on the atmosphere side of at least one of the thin-walled cylinders. In a coaxial waveguide structure configured such that cooling air can be blown onto the surface of the dielectric airtight window plate, at least one of the inner conductor and the outer conductor joined to the airtight window plate is provided with the following: Conductor cylindrical parts that form an alignment annular groove together with the conductor thin cylinder are provided to protrude toward the airtight window plate at predetermined intervals, and are cooled through ventilation holes provided in the inner part of the alignment annular groove. A coaxial waveguide structure characterized by being configured to blow air. (2) A dielectric partition plate is placed between the inner conductor and the outer conductor on the atmosphere side at a distance from the dielectric airtight window plate, and an annular matching groove is formed between the dielectric airtight window plate and the partition plate. A coaxial waveguide according to claim 1, further comprising a body cylinder.