JPH0127548B2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field of the Invention The present invention relates to a device for changing the characteristics of a high frequency device such as a microwave band, and in particular a device for changing characteristics such as the resonant frequency characteristics or phase characteristics of a resonant cavity or waveguide. Regarding improvements.

Background Art and Problems For example, a high-frequency resonant cavity with variable resonance frequency is used in a linear klystron used in a microwave power amplification device, a high-frequency device such as a particle accelerator, or various other high-frequency devices. .
Various types of devices for changing the characteristics of high-frequency cavities are known, one of which is a device in which a tuner structure is connected to a high-frequency coupling hole formed in a part of the cavity wall and is cupped into the cavity. There is a known type in which the resonant characteristics of the cavity can be varied by moving a shaped conductor forward and backward. Furthermore, a plurality of phase characteristic variable conductors may be inserted into a part of the waveguide in order to change the phase of the transmitted wave. Furthermore, devices are also known in which a movable shorting plate is provided in the cavity or waveguide to change the characteristics thereof. The present invention relates to a characteristic variable device for such a high frequency device.

By the way, in cases where the operating frequency of the high-frequency device is very high, or in the case of a high-frequency cavity where the characteristics of the device are rarely changed once they have been adjusted, the frequency variable device can also be relatively small and have a simple structure. There are many cases. However, high-frequency power of several tens of kilowatts or more is supplied, the frequency is relatively low, and the characteristic variable range is wide. Therefore, the size of the cup-shaped conductor for characteristic variable and its movement range are large, and furthermore, in high vacuum. In the characteristic variable device of the high frequency device used, forced cooling of the movable cup-shaped conductor is particularly necessary.
Furthermore, the variable mechanism becomes large and the device as a whole becomes complicated. In order to cool the cup-shaped conductor and move it minutely and precisely, it is advantageous to have a structure in which a coolant is introduced and discharged through a movable shaft that supports the cup-shaped conductor. However, in this case, especially if the movable shaft is made hollow for water to pass through, the configuration of the drive mechanism for moving the shaft forward and backward is restricted.
For this reason, when the movable distance is relatively long, the mechanism to prevent lateral vibration of the movable axis becomes particularly complicated, and the outwardly projecting dimensions of the device become long, making it difficult to obtain compact and highly accurate characteristic variation. It becomes difficult.

Purpose of the Invention The present invention solves the above-mentioned disadvantages, and provides a compact and highly accurate characteristic variable device even when the device handles high-power high-frequency energy at a relatively low operating frequency. It is.

Summary of the Invention The present invention provides a movable main shaft that supports a variable characteristic body, that is, a tuner cup, in the form of a hollow rod so that a refrigerant can pass therethrough, and a support frame structure is provided along this movable main shaft, parallel to the side of this shaft. A movable rotary screw shaft is installed on the screw shaft, and the sliding nut screwed onto this screw shaft and the movable main shaft are integrally fixed with a connecting plate, whereby the movable main shaft can be moved forward and backward. be. In addition, a guide rod is provided on the opposite side of the screw shaft in parallel to the main shaft, and both sides of the connecting plate are supported by these screw shafts and guide rods while moving, thereby causing the movable main shaft to oscillate laterally. It is possible to make minute movements without any problems, and the tuner structure as a whole can be made relatively compact. Therefore, the present invention is particularly suitable for high-frequency equipment for high power use in which a refrigerant for cooling the tuner cup is introduced and discharged through the interior of the movable main shaft.

Embodiments of the Invention A configuration in which the present invention is implemented in a resonant cavity device for acceleration of a particle accelerator will be described below with reference to the drawings. Note that the same parts are represented by the same symbols.

In a particle accelerator, microwave energy is introduced from the outside into a resonant cavity for acceleration in order to increase the kinetic energy of charged particles such as electrons or protons.
That is, as shown schematically in FIG. 1, a hollow tube 2 has a hole 22 through which charged particles pass in the center of a cylindrical cavity wall 21 constituting an accelerating resonant cavity 20.
3 is provided, and microwaves in the 500 MHz band, for example, are supplied into the cavity 20 from an external waveguide 25 connected to an input coupling window 24 provided in a part of the cavity wall 21. . On the other hand, a tuner 27 coupled to the cavity 20 by a flange 26 is provided, and a cup-shaped frequency correction tuner cup 28 is provided.
is movably mounted within the cavity. The cup 28 is configured to be capable of piston movement as shown by an arrow 31 by a drive device 30 via a movable main shaft 29. The reference numeral 28a in the figure represents the position where the cup is pushed into the cavity.

During operation of this device, a high frequency current flows through the inner surface of the cavity wall 21, and due to the resulting power loss, the cavity wall expands thermally and the natural resonant frequency of the cavity changes. As a result, matching with the input high frequency becomes inappropriate, resulting in a decrease in efficiency and the like. In order to prevent this, a detector detects the change in the resonant frequency of the cavity, and the controller 33 processes the signal to control the driving device 30.
The tuner cup 28 is inserted into the cavity and the resonant frequency is automatically corrected. Therefore, the cup 28 of Chuyuna 27
is moved as shown by arrow 31 so that the resonant frequency of the cavity is always constant. The inside of the cavity 20 is maintained at an ultra-high vacuum of, for example, 10 ^-9 Torr during operation.
Therefore, the internal space 34 of the tuner 27 is also maintained at an ultra-high vacuum by the vacuum bellows 35. A part of the high frequency current flowing through the inner wall of the cavity is transferred to the outer cylinder 3 of the tuner 27 .
It also flows to the inner wall surface of 6. If this high-frequency current reaches and flows through the bellows 35 and the support part of the movable main shaft 29, each part of the bellows will generate heat, causing damage to the vacuum-tight joint, or damage to small gaps in the support part of the movable main shaft 29, as described below. There is a risk of high frequency discharge occurring in the roller bearings, etc. To prevent this, a cylindrical sliding contact structure 37 is attached to electrically short-circuit the outer cylinder 36 of the tuner 27 and the cylindrical cavity wall of the tuner cup 28. Further, the movable main shaft 29 is supported by the support frame structure 38 via a part of the drive mechanism. The cavity wall 21, the tube cup 28, the outer cylinder 36, etc. are made of metal with excellent electrical conductivity and thermal conductivity.
For example, it is made of copper.

Next, details of each part will be explained with reference to FIGS. 2 and 3.

A cylindrical wall 42 having a flange 26 at its tip protrudes and communicates with a tuner coupling hole 41 formed in a part of the resonant cavity wall 21, and a water-cooled cylindrical wall 44 having flanges 26 and 43 is further provided on the outside thereof. It is electrically and vacuum-tightly bonded and fixed. A cooling water jacket is provided on the outer periphery of the water-cooled cylindrical wall 44, and the cooling water is introduced and discharged through pipes 46 and 47. Both cylindrical walls 42 and 44 constitute an outer cylinder 36 of the tuner 27 . This outer cylinder 3
Inside of 6 and close to this, there is Chuna Cup 2.
8 are movably arranged. The cup 28 has a cylindrical shape with a bottom, and is mechanically held by being fixed to a movable main shaft 29 in the form of a hollow rod through an airtight sealing plate 48 at the center and middle portions of the bottom. Cooling water is poured into the hollow movable main shaft 29 in the direction indicated by the arrow l.
A thin water guide pipe for inflow and outflow is inserted as shown in FIG. Inside the bottom of the tube cup 28, a hollow cylindrical cooling water guide tube 51 is provided at a slight distance from the cup inner wall surface so that the cooling water flows along the cup inner wall surface. It is fixed liquid-tight. A water passage hole 52 for discharging cooling water is provided in the main shaft 29 near the sealing plate 48, so that the cooling water is discharged to the outside through the outer peripheral space of the pipe 49 as indicated by arrow l. . A support substrate 53 having a flange for attaching a tuner drive unit is electrically and vacuum-tightly joined to the flange 43 of the cylindrical wall 44 . This support substrate 53
A through hole through which the movable main shaft 29 passes is formed in the center, and a large number of elastic metal supports 54, 54, . Bolts 55, 55 in a circle
It is fixed by... Each elastic metal support 5
4, 54... are individually fixed to the ends of the conductor contacts 56, 56... made of metal blocks, and are attached to the skirt portion 2 of the tuner cup 28.
It is pressed into contact with the inner circumferential wall surface of 8b.

Therefore, on this surface side of the support substrate 53, at least three, for example four, roller bearings 57,
57 . . . are provided at equal intervals on the circumference, and the rollers 58, 58 . Further, on the other side of the support substrate 53, a vacuum is provided which covers the outer periphery of the movable main shaft and extends outward along the outer periphery of the movable main shaft, and whose end portion is vacuum-tightly sealed to the end outer peripheral wall of the movable main shaft 29. A bellows 35 is attached. In this way, the cavity 20 , the inner space 34 of the tuner 27 , and the inner space of the bellows 35 are maintained at a high vacuum. Therefore, the sliding short-circuit structure 37 and each roller bearing 57 and roller 58 are also located in a high vacuum. Further, a drive motor 59 is attached to the support substrate 53 and rotates a rotatable screw shaft 64 via a drive shaft 60, gears 61, 62, and a bearing 63. The screw shaft 64 has a thread cut on its outer periphery, and one end thereof is rotatably supported by a bearing provided on the support substrate 53 and the other end is a bearing 6 provided on the fixed plate 65.
3 and is integrally fixed to the gear 62. A sliding nut 66 is screwed onto this screw shaft 64, and a connecting plate 67 is fixed to this nut 66. The connecting plate 67 is fixed to the outer periphery of a joint 50 that is integrally connected to the movable main shaft 29, and its end is supported by a guide rod 68 for preventing lateral vibration via a pair of guide rollers 69, 69. has been done. In this way, the motor 59, drive shaft 60, gear 6
1 and 62, the screw shaft 64, the sliding nut 66, the connecting plate 67, and the guide roller 69 form a drive mechanism that moves the movable main shaft 29 back and forth in the lateral direction. The fixed plate 65 includes four fixed support rods 70, 70.
... is mechanically fixed to the support substrate 53, and the guide rod 68 is also bridged and fixed to the fixed plate 65 and the support substrate 53. In this way, the fixed support rods 70, 70, . Therefore, the bearing mechanism that supports the movable main shaft 29 includes a roller bearing, that is, an intermediate bearing structure that supports the intermediate portion of the movable main shaft 29, and a drive holding structure that supports the outer end of the movable main shaft and drives this main shaft, that is, the above-mentioned. The support frame structure 38 and a part of the drive mechanism. In other words, the main shaft is supported at two places, the middle part located in the vacuum region with the vacuum bellows in between, and the outer end part.

The tuner cup 28 of the tuner 27 is the cavity 20
You can advance and retreat as follows. That is, when the screw shaft 64 is rotated through the gear by the rotation of the motor 59, the sliding nut 66 screwed thereon moves in the lateral direction in the figure. Via the connecting plate 67 and the joint 50, which are integrally connected to this nut 66, the movable main shaft 29 can also be moved laterally together in the inner region of the support frame structure 38, so that the cup 28 fixed thereto can be moved in the cavity. Advance or retreat within 20 seconds. In particular, in this device, the movable main shaft 29 is supported at its outer end by a support frame structure 38 consisting of a fixed plate 65, a support rod 70, etc. via a connecting plate 67 and a screw shaft 64 as described above, and an intermediate portion is adapted to move while being supported by the support substrate 53 by rollers 58 and roller bearings 57. Therefore, the movable main shaft 29 and the tuner cup 28 fixed thereto can be moved forward and backward without causing any wobbling of the central shaft. The tuner cup 28 and the outer cylinder 36 are configured to have a small gap g of about 2 mm in the case of a cavity having a resonant frequency in the 500 MHz band, for example. If this gap g is too narrow, high-frequency discharge is likely to occur, and if it is too wide, the high-frequency current flowing in the direction of the drive short circuit structure 37 will become too large, so this gap g must always be maintained at the set dimension. In other words, if the tuner cup 28 shakes as it moves, the vibration itself causes the disadvantage that the resonant frequency characteristics of the cavity fluctuate, and also causes high-frequency discharge where the gap becomes narrow. There is a risk that this is not desirable. According to the above-described embodiments of the present invention, such inconveniences are reliably solved and the device operates stably.

In addition, the skirt portion 28b of the Chuna Cup 28
The sliding short-circuiting structure 37 that contacts the inner peripheral surface of is constructed as shown in FIGS. 4 and 5. That is, the support 54 is made of an elastic metal material with excellent conductivity such as phosphor bronze or beryllium copper.
is formed into an L-shape, and a generally rectangular parallelepiped, ie, block-shaped conductor contact body 56 is fixed to the tip thereof. This contact body 56 is mainly made of copper or silver with graphite mixed therein. Preferably, these metal powders are mixed, sintered, and formed into a block shape. Sliding contact surface 56
A is formed into an arc shape that fits the contact surface of the mating member, that is, the inner circumferential wall surface of the skirt portion 28b of the tuner cup in the above embodiment, so that surface contact is made over a wide area. Further, the elastic metal support 54 is bonded with a conductive adhesive 71 such as silver paste, and is fixed from behind with a bolt 72. As a result, a planar electrical connection between the contact body and the support body is obtained, and even if any one of them becomes overheated and the adhesive material 71 deteriorates, the block-shaped contact body 56 will not fall off. There is no risk and reliability is increased. In this way, a large number of elastic metal supports having the contact bodies 56 are arranged in a circle along the skirt portion 28b, and the L-shaped ends are arranged at a small interval from each other, that is, with a blocking dimension that prevents high frequency waves from leaking toward the bellows. , electrically and mechanically connected to the flange 53 by bolts.
The assembly is then performed so that the contact body 56 is always strongly pressed against the skirt portion 28b.

As shown in FIGS. 6 and 7, the movable main shaft 2 in the inner space of the skirt portion of the cup 28
A block-shaped conductor contact body 56 may be configured to be in contact with the outer circumferential surface of the conductor 9. In this case, bearing 5
7 and its roller 58, a support base 76 having a crank-shaped half cross section is fixed to the flange 53,
A plurality of elastic metal supports 5 are arranged in a circle on top of this.
Fix 4. This allows a relatively small number of supports 54 and contact bodies 56 to be constructed.

Of the bearing mechanisms that support the movable main shaft 29, the intermediate bearing assembly 80 that supports the intermediate portion thereof includes rotatable rollers 58, 58 that abut the outer periphery of the movable main shaft 29 at equal intervals, as shown in FIGS. 8 to 10. Four roller bearings 57, 57, . . . are fixed to the support substrate 53. Each roller 58, 58...
... has a circumferential surface formed into a concave surface 81 that fits the main shaft 29, and is supported by a roller shaft 82. Each of them is firmly pressed and fixed in the direction of the main axis by a set screw 83. These bearings do not use lubricants that cause so-called gas emissions. Note that the roller bearing may have a ball bearing, and in this case as well, no lubricant that causes gas release is used.

In this way, the movable main shaft 29 has at least three (four in the example shown in the figure), preferably about six, fixed to the support substrate in the vacuum area in the middle part and in the part where the high frequency current does not reach. It is supported by rollers so that it can move forward and backward in the axial direction.

Now, the outer end holding structure 85 that supports the outer end of the movable main shaft 29 and drives this main shaft is a support frame structure as shown in FIGS. 2, 3, 11, and 12. A rotary screw shaft 64 and a guide rod 68 are bridged between the fixed plate 65 and the support substrate 53, which constitute a part of the screw shaft, and a sliding nut 66 is screwed onto the screw shaft. It is constructed by a connecting plate 67. The connecting plate 67 is connected to the screw shaft 6 on one side with the main shaft 29 in between.
4, and a guide rod 68 via guide rollers 69, 69 on the opposite side. When the gears 61 and 62 that mesh with each other are rotated by the motor 59, the threaded shaft 64 that is integrated with the gear 62 rotates, and the threaded portion 6 formed therein rotates.
A sliding nut 66 which is screwed into the sliding nut 4a and a connecting plate 67 fixed to this nut are moved. Connecting plate 67
The movable main shaft 29, which is fixed to the connecting plate 67 via a joint 50, moves while being held from both sides by a screw shaft 64 and a guide rod 68, which are provided parallel to the connecting plate 29. It can be held and moved forward and backward in the axial direction without causing any friction. In this way, the movable main shaft is substantially held at two locations, the intermediate portion and the outer end portion, with the vacuum bellows in between, and is movable forward and backward by the drive mechanism. As the movable main shaft 29 moves, a joint 50 for introducing and discharging cooling water through the interior of the main shaft and a pipe for connecting an external water pipe also move laterally. The sliding nut, connecting plate, and joint portion are attached to the support frame structure 38.
The movable main shaft 29 reciprocates between the support substrate 53 and the fixed plate 65, so that the movable main shaft 29 does not protrude outward beyond the fixed plate.

In the above embodiment, the positions of the screw shaft 64 and guide rod 68 that support the connecting plate on both sides are set to the main shaft 29.
Although the main shaft 29 is provided at a symmetrical position, that is, at a 180 degree position, the main shaft 29 is not limited to this, and any position that supports the main shaft 29 from substantially both sides may be used. Alternatively, a plurality of guide rods may be provided, and the structure is such that these guide rods prevent horizontal vibration of the main shaft.

Further, the support substrate may have the same function as the above embodiment, and may be formed by integrally forming a part of the outer cylinder into a perforated lid shape. Furthermore, the support frame structure 38 is not limited to being composed of a plurality of support rods, but may be composed of a combination of plate-like bodies, and the gear may also be located inside the fixed plate. . Further, although the guide rod 68 may be omitted, it is more advantageous to provide this guide rod for more stable movement. The structure of this guide rod may be such that a groove is formed in the guide rod along the movable main shaft, and a roller or protrusion that slides by fitting into the groove is attached to the connecting plate.

Effects of the Invention As explained above, the present invention has the outer end of the movable main shaft for advancing and retracting the characteristic variable tuner cup.
The movable main shaft is moved via a connecting plate and a sliding nut by a drive rotary screw shaft arranged in parallel to the side of the movable main shaft in the inner part of the support frame structure, and the outer end of these movable main shafts, The range of movement of the connecting plate and the sliding nut is accommodated within the inner part of the support frame structure. This makes it possible to keep the device relatively compact and to increase the travel distance of the tuner cup, up to approximately the length of the support frame structure. Even if the movable nut is made into a hollow rod and the refrigerant for cooling the tuner cup is introduced into and discharged from the rod, reliable and stable driving can be achieved.

In addition, by configuring the connecting plate to be held and moved from both sides by a screw shaft and a guide rod,
It reliably prevents lateral vibration of the movable main shaft and enables highly accurate forward and backward movement.

Therefore, the present invention is particularly suitable for precise variable adjustment mechanisms such as resonant frequency characteristics and phase characteristics of high frequency devices such as resonant cavities and waveguides that handle ultra-high power high frequency energy, and is relatively compact and has a large stroke. can be varied.

[Brief explanation of drawings]

Fig. 1 is a schematic cross-sectional view showing one embodiment of the present invention, Fig. 2 is a sectional view of its main part, Fig. 3 is a side view thereof, Fig. 4 is a partial perspective view thereof, and Fig. 5 is its main part. 6 is a partial sectional view showing another embodiment, FIG. 7 is a partial perspective view thereof, FIG. 8 is a sectional view of a main part showing still another embodiment, and FIG. Side view, 1st
0 is a partial perspective view thereof, FIG. 11 is a cross-sectional view taken along line 11-11 in FIG. 3, and FIG. 12 is a cross-sectional view taken along line 12-12 in FIG. 20 ... Resonant cavity, 21... Cavity wall, 27 ...
Chuyuna, 28... Chuyuna Cap, 28b...
Skirt part of cup, 35... Vacuum bellows, 3
6...Outer cylinder, 37 ...Sliding short-circuit structure, 38...Support frame structure, 49...Water guide pipe, 50...Joint, 53...Support board, 80 ...Intermediate bearing structure, 85...Outside end holding structure, 57...roller bearing, 58...roller, 59...motor, 61,
62...Gear, 65...Fixing plate, 70...Support rod, 64...Screw shaft, 66...Sliding nut, 67
... Connecting plate, 68 ... Guide rod, 69 ... Guide roller.

Claims (1)

[Scope of Claims] 1: an outer cylinder protruding from a part of the wall of the high-frequency device; a tuner cup movably disposed through the inner side of the outer cylinder so as to change the characteristics of the device; a hollow rod-shaped movable main shaft fixed to the tuner cup to support the cup so as to be movable in the axial direction, the other end of which extends outward beyond the end of the outer cylinder; and an outer end of the movable main shaft. a cooling device installed to introduce and discharge a refrigerant from the main shaft through the main shaft to the tuner cup; a support substrate made of a conductor fixed to the end of the outer cylinder and having a through hole through which the movable main shaft passes; , one end is hermetically joined to the outer cylinder directly or via the support substrate, and the other end is extended along the movable main shaft and is airtightly attached to the outer peripheral wall near the outer end of the main shaft. a vacuum bellows, a bearing mechanism that supports the movable main shaft, and a support frame structure having one end fixed to the support substrate, the other end extending toward the outer end of the movable main shaft, and a fixing plate at the tip. and a drive mechanism that is attached to the support frame structure and moves the movable main shaft forward and backward in the axial direction by a drive motor, and the drive mechanism is located beside and parallel to the movable main shaft, and A rotating screw shaft supported by a support substrate and a support frame structure and rotated by a drive motor via gears, a sliding nut screwed onto this shaft, and an integral connection between this sliding nut and the movable main shaft. The sliding nut and the connecting plate are located between the supporting substrate and the fixed plate of the support frame structure and are configured to move integrally with the movable main shaft in the axial direction. A characteristic variable device for a high frequency device, characterized in that: 2. An outer cylinder protruding from a part of the wall of the high-frequency device, a tuner cup movably disposed through the inner side of the outer cylinder so as to vary the characteristics of the device, and one end fixed to the tuner cup and connected to the tuner cup. A hollow rod-shaped movable main shaft that supports the cup so as to be movable in the axial direction and whose other end extends outward from the end of the outer cylinder; a cooling device installed to introduce and discharge a refrigerant into the tuber cup; a support substrate made of a conductor that is fixed to the end of the outer cylinder and has a through hole through which the movable main shaft passes; a vacuum bellows hermetically joined to the outer cylinder via the support substrate, the other end of which extends along the movable main shaft and is airtightly attached to the outer peripheral wall near the outer end of the main shaft; a bearing mechanism that supports a main shaft; a support frame structure having one end fixed to the support substrate and the other end extending toward the outer end of the movable main shaft and having a fixing plate at the tip; and the support frame structure. a drive mechanism that is attached to the movable main shaft and moves the movable main shaft forward and backward in the axial direction by a drive motor, the drive mechanism is located beside and parallel to the movable main shaft, and is connected to the support substrate and the support frame structure. The rotary screw shaft is supported by a rotary screw shaft and rotated by a drive motor via a gear, a sliding nut screwed onto the shaft, and a connecting plate that integrally connects the sliding nut and the movable main shaft. a guide rod is provided parallel to the screw shaft and on the opposite side of the movable main shaft, and held between the support substrate and the fixed plate;
The connecting plate is slidably locked to this guide rod,
A portion of the connecting plate is movably supported on the screw shaft by the sliding nut, and another portion is movably supported on the guide rod on the opposite side of the screw shaft, so that the connecting plate is movably supported on the screw shaft by the sliding nut. and a characteristic variable device for a high frequency device, characterized in that a connecting plate is located between the support substrate and the fixed plate of the support frame structure and is configured to move in the axial direction integrally with the movable main shaft.