JP4678239B2 - Vacuum variable capacitor - Google Patents

Description

  The present invention relates to a vacuum variable capacitor used in a transmission circuit of a high power transmitter, a high frequency power supply circuit for a semiconductor manufacturing apparatus, a tank circuit of an induction heating apparatus, or the like.

  A vacuum variable capacitor proposed in Japanese Patent Application Laid-Open No. H10-228707 is one that stabilizes the withstand voltage / capacitance characteristics of the vacuum variable capacitor and reduces the overall length. A capacitor of the same type as this capacitor will be described with reference to FIG. In the figure, reference numeral 1 denotes an insulating cylinder made of ceramics. A fixed side end plate 2 is joined to one end of the insulating cylinder 1, and a movable side end plate 4 is connected to the other end of the insulating cylinder 1 via a connecting cylinder 3. Bonding to form the vacuum vessel 5. A plurality of cylindrical electrode plates F1, F2,..., Fn having different diameters are attached concentrically on the inner surface side of the fixed side end plate 2 to form the fixed electrode 6. A center pin 7 is erected at the center on the inner surface side of the fixed side end plate 2 via a fixed guide 8. The movable electrode support plate 9 is disposed in the vacuum vessel 5 so as to face the fixed side end plate 2. The movable electrode 10 is configured by concentrically attaching a plurality of cylindrical electrode plates M1, M2,..., Mn having different diameters so that they can be inserted / removed between the cylindrical electrode plates of the fixed electrode 6 without contact.

  Reference numeral 11 denotes a cylindrical movable lead that is provided integrally through the center of the movable electrode support plate 9, and the movable lead 11 is slidably fitted to the center pin 7. The movable lead 11 and the center pin 7 are electrically insulated. A hole 4a is provided in the center of the movable side end plate 4, and a cylindrical heat pipe 12 is erected on the inner surface side of the movable side end plate 4 at the periphery of the hole 4a. A flange 12a protruding inward is provided. Reference numeral 13 denotes an adjusting screw having a male screw portion 13 a formed on the outer periphery, one end of which is fitted and fixed to the movable lead 11, and the other end is inserted into the flange portion 12 a of the heat pipe 12. Reference numeral 14 denotes an adjustment nut having an internal thread portion 14a threadedly engaged with the external thread portion 13a of the adjustment screw 13 on the inner circumference on one end side, and this one end side is rotated via a bearing 15 below the flange portion 12a. It is supported freely.

  A female screw portion 13b is provided at the other end of the adjustment screw 13, and a stop screw 16 is screwed into the female screw portion 13b. Further, the adjustment nut 14 is formed with a larger-diameter hole 14b continuous with the female screw portion 14a, and a stepped portion 14c is formed between the female screw portion 14a and the hole 14b. A cylindrical bellows 17 for separating the vacuum side and the atmosphere side is provided on the outer peripheral side of the movable lead 11 and the heat pipe 12, one end of which is attached to the movable electrode support plate 9, and the other end is the movable side end plate 4. The vacuum state in the vacuum vessel 5 is maintained.

  When adjusting the maximum capacitance value of the vacuum variable capacitor having the above-described configuration, first, before inserting the stop screw 16, the adjustment nut 14 is slightly turned to the right (in the case of a right screw), and the tip of the center pin 7 is turned on. Then, the movable lead 11 is moved slightly downward from the position of the maximum capacitance where the inner end of the adjustment screw 13 abuts, and adjusted to the defined maximum capacitance value. This slight adjustment amount is determined in accordance with the variation in the capacitance of the vacuum variable capacitor.

  Next, in this state, the stop screw 16 is screwed into the female screw portion 13b until the head portion 16a contacts the stepped portion 14c of the adjusting nut 14, and is fixed to the adjusting screw 13 with an adhesive or the like. The stop screw 16 and the adjusting nut 14 are not bonded. As a result, the rising position of the adjusting screw 13 is restricted, and even if the adjusting nut 14 is turned counterclockwise from the position of the maximum capacitance value, the head portion 16a of the stop screw 16 does not come into contact with the step portion 14c, The adjusting screw 13 does not rise.

  For adjusting the capacitance, for example, when the adjustment nut 14 is turned to the right, the adjustment screw 13 is moved downward. When the adjustment nut 13 is rotated counterclockwise, the adjustment screw 13 is moved upward, thereby moving the movable electrode 10 up and down and facing the fixed electrode 6. This is done by changing the total area.

Since the inside of the vacuum vessel 5 is vacuum, the vacuum variable capacitor always exerts a force that pushes the adjustment screw 13 upward, and this force also acts on the adjustment nut 14, generating a surface pressure on the flange 12 a, and adjusting it. Although a large rotational torque is required for the rotation of the nut 14, since the bearing 15 is provided, this rotational torque can be reduced. Conventional vacuum variable capacitors are also shown in Patent Document 2 and Patent Document 3.
JP-A-8-97088 Japanese Patent No. 3264004 JP 2001-217147 A

In recent years, with the increase in capacity of a high-frequency power supply for semiconductor manufacturing equipment, the vacuum variable capacitor is also required to have a large current. For this purpose, it is necessary to reduce the internal loss of the vacuum variable capacitor. Here, when the equivalent circuit of the vacuum variable capacitor is drawn in a simplified manner, it is as shown in FIG. Co is the capacitance of the insulating cylinder 1, Rb is the resistance of the bellows 17, Cc is the capacitance of the center pin 7, and Ce is the capacitance of the electrode portions 6 and 10. Since the current Io flowing through the insulating cylinder 1 is 2πfCoV and the heat generation amount Wo of the insulating cylinder 1 is V × Io × tan δ,
Wo = 2πfCo × V ² × tan δ (1)
It becomes. Where V is a voltage applied to the vacuum variable capacitor, f is its frequency, and tan δ is a dielectric loss of the insulating cylinder 1. The total current I of the vacuum variable capacitor is 2πfCV, where C is the total capacitance, and the current Ic flowing through the center pin 7 is I × Cc / (C−Co). Since the heat generation amount Wc of the center pin 7 is Vc × Ic × tan δ, where the dielectric loss of the center pin 7 is tan δ, the applied voltage Vc≈V to the center pin 7 is
Wc = 2πfC × Cc / (C -Co) × V 2 × tanδ (2)
It becomes. Accordingly, the heat generation amounts Wo and Wc of the insulating cylinder 1 and the center pin 7 increase as the voltage is increased and the capacitance is decreased. If tan δ is set to 1/10, the heat generation amount is also reduced to 1/10.

  In addition, current flows through the bellows due to the structure of the vacuum variable capacitor. However, in order to increase the current of the vacuum variable capacitor, it is necessary to increase the current carrying capacity of the bellows, and it is necessary to increase the diameter of the bellows and increase the current carrying area. is there.

However, in the conventional vacuum variable capacitor shown in FIG. 6, the influence due to heat loss (including sliding friction) of the center pin 7 which is a sliding portion and the influence due to heat generation of the insulating cylinder 1 become problems. There was a possibility. Further, since the bellows 17 is thin and the material is copper or stainless steel coated with Cu, the current carrying capacity of the vacuum variable capacitor is determined by the bellows 17, and the current carrying capacity can be increased by increasing the diameter of the bellows 17. However, the size of the vacuum variable capacitor could not be reduced. Further, the self-closing force due to the pressure difference between the vacuum side and the atmosphere side increases, the rotational torque of the adjusting nut 14 increases, and the motor and the control circuit for driving the adjusting nut 14 become large. Furthermore, the capacitance can be adjusted by rotating the adjustment nut 14. However, when a radial stress is applied to the adjustment nut 14, the movable lead 11, the fixed guide 8, and the center pin that are sliding portions are applied. The frictional resistance of No. 7 increased, and there was a possibility that the sliding would be hindered.

  The present invention has been made to solve the above-described problems, and can reduce internal loss, can carry a large current, and can be miniaturized. It is an object of the present invention to obtain a vacuum variable capacitor that can reduce the rotational torque of the adjusting nut without causing any trouble in sliding even if the stress of the above acts.

According to a first aspect of the present invention, there is provided a vacuum variable capacitor comprising: a vacuum vessel in which both ends of an insulating cylinder are closed with a fixed side end plate and a movable side end plate; a fixed electrode erected on the inner surface of the fixed side end plate; A movable electrode support plate disposed opposite to the fixed side end plate, a movable electrode standing on the fixed side end plate side of the movable electrode support plate and facing the fixed electrode, and one end of the movable electrode support plate The other end is attached to the movable side end plate, and is provided with a cylindrical bellows that separates the vacuum side and the atmosphere side, and projecting inwardly into the hole of the movable side end plate on the inner peripheral side of the bellows And an adjustment screw having one end attached to the movable electrode support plate, inserted into the heat pipe, provided with a male screw portion on the outer periphery of the other end, and formed with a female screw portion on the other end. Stroke that is screwed into the female thread of the screw And a stepped portion that can be engaged with the male screw portion of the adjusting screw and the head portion of the stop screw. An adjustment nut, a heat radiation guide that is attached to the movable electrode support plate on the inner peripheral side of the bellows and covers the outer periphery of the heat pipe, and an air hole that communicates the inner peripheral side and the outside air side of the bellows.

  The vacuum variable capacitor according to claim 2 is provided with a linear bearing at a sliding portion with an adjustment screw of the heat pipe.

According to a third aspect of the present invention, there is provided a vacuum variable capacitor in which both ends of an insulating cylinder are closed by a fixed side end plate and a movable side end plate, a fixed electrode standing on the inner surface of the fixed side end plate, and a fixed side end plate A center pin erected at the center of the inner surface, a movable electrode support plate disposed in the vacuum container facing the fixed side end plate, and a fixed electrode on the fixed side end plate side of the movable electrode support plate. The movable electrode provided, one end is attached to the movable electrode support plate, the other end is attached to the movable side end plate, and a cylindrical bellows that separates the vacuum side and the atmosphere side, and on the inner peripheral side of the bellows A movable lead attached to the movable electrode support plate, slidably fitted to the center pin and insulated from the center pin, a screw receiving portion provided in a hole of the movable side end plate on the inner peripheral side of the bellows, and one end thereof Attached to the movable lead In addition, an adjustment screw that is inserted into the screw receiving portion and provided with a male screw portion on the outer periphery and has a female screw portion formed at the other end, a stop screw that engages with the female screw portion of the adjustment screw, and a bearing in the screw receiving portion And an adjustment nut having a female screw portion that is screwed with a male screw portion of the adjustment screw and a step portion engageable with a head portion of the stop screw, and a screw receiver on the inner peripheral side of the bellows A heat pipe attached to the movable side end plate on the outer peripheral side of the part, and an air hole communicating the inner peripheral side and the outside air side of the bellows.

The vacuum variable capacitor according to claim 4 is a vacuum vessel in which both ends of the insulating cylinder are closed by a fixed side end plate and a movable side end plate, a fixed electrode erected on the inner surface of the fixed side end plate, and fixed in the vacuum vessel A movable electrode support plate disposed facing the side end plate, a movable electrode erected on the fixed side end plate side of the movable electrode support plate so as to face the fixed electrode, and one end attached to the movable electrode support plate In addition, the other end is attached to the movable side end plate, and is provided with a cylindrical bellows that separates the vacuum side and the atmosphere side, and projects inwardly into the hole of the movable side end plate on the inner peripheral side of the bellows. A heat pipe made of a conductive material that also serves as a moving guide, one end is attached to the movable electrode support plate, is slidably inserted into the heat pipe, and has a male screw portion on the outer periphery of the other end, and at the other end An adjustment screw with a female thread A sliding member that is attached to the movable electrode support plate on the inner peripheral side of the bellows and that is made of a conductive material that slides with the heat pipe, and a sliding that is made of a conductive material provided at a sliding portion between the sliding member and the heat pipe A contact, a stop screw that engages with the female thread of the adjustment screw, and a support screw that is rotatably supported via a bearing on the inner peripheral side of the heat pipe, and a female screw that engages with the male screw of the adjustment screw and the stop screw. An adjustment nut having a step portion engageable with the head and an air hole communicating the inner peripheral side and the outside air side of the bellows are provided.

The vacuum variable capacitor according to claim 5 is an insulating cylinder formed of high-purity alumina.

  As described above, according to the first aspect of the present invention, by eliminating the center pin, it is possible to eliminate the heat generated by energizing the center pin and the heat generated by sliding, thereby reducing the internal loss and increasing the energizing capability. it can. In addition, a heat pipe and a heat radiation guide are provided between the inner peripheral side of the bellows and the sliding part of the adjusting screw, and air is allowed to flow into the inner peripheral side of the bellows for cooling so that the heat of the bellows is adjusted. The sliding portion of the screw can be prevented from being adversely affected, the adjustment screw can be slid and the adjustment nut can be smoothly rotated, and the current-carrying capacity can be increased. Furthermore, the bearing is provided between the heat pipe and the adjustment nut, and the resistance to the radial load of the adjustment nut can be improved.

  According to the second aspect, the linear bearing is provided in the sliding portion with the adjustment screw of the heat pipe, so that the sliding torque of the adjustment screw can be reduced and the rotational torque of the adjustment nut can also be reduced. . In addition, a heat pipe and a heat radiation guide are provided between the bellows and the linear bearing to shield the heat of the bellows, and an air hole for cooling the bellows is provided. The adjustment screw can be smoothly slid and the adjustment nut can be smoothly rotated.

According to claim 3 , while providing the air hole which connects the inner peripheral side of the bellows and the outside air side, the heat pipe is provided between the inner peripheral side of the bellows and the screw receiving portion, and the bellows is cooled. While increasing the current-carrying capacity, the influence of the heat of the bellows on the sliding part and the rotating part on the inner peripheral side of the heat pipe can be reduced, and sliding and rotation can be performed smoothly.

According to claim 4 , since the center pin is eliminated, the heat generation does not occur. For this reason, internal loss is reduced and the current carrying capacity can be improved. In addition, since energization is performed through the sliding member, the sliding contact, and the heat pipe, the current can be increased and the size can be reduced as compared with the case where the energization is performed by the bellows. In addition, the heat pipe has a sliding guide function, and a bearing is provided between the heat pipe and the adjustment nut. Therefore, even if a lateral load is applied to the adjustment nut, the adjustment nut rotates and the adjustment screw slides. Will not be disturbed. In addition, outside air is introduced to the inner peripheral side of the bellows, and a heat pipe is provided on the outer peripheral side of the sliding part and the rotating part. The influence of the heat of the bellows can be reduced, and sliding and rotation can be performed smoothly.

According to the fifth aspect , since the insulating cylinder is made of high-purity alumina, the dielectric loss is reduced, the heat generation of the insulating cylinder is reduced, and the current carrying capacity can be improved by reducing the internal loss.

Best Embodiment 1
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of a vacuum variable capacitor according to Embodiment 1 of the present invention, and no center pin or the like is provided. A hole 4 a is provided in the center of the movable side end plate 4, a cylindrical heat pipe 18 is inserted into the hole 4 a, and a flange portion 18 a of the heat pipe 18 is attached to the outer surface of the end plate 4. Reference numeral 19 denotes an adjustment screw having an upper end attached to the movable electrode support plate 9. The adjustment screw 19 is inserted into the heat pipe 18, and a male screw portion 19a is provided on the outer periphery of the other end side. A linear bearing 20 that slides the adjusting screw 19 in the axial direction is provided on the inner periphery of the heat pipe 18. Further, the upper end of a heat radiation guide 21 that shields between the inner peripheral side of the bellows 17 and the heat pipe 18 is attached to the opposite side of the movable electrode support plate 9 to the movable electrode 10. In addition, air holes 4b and 18b are provided in the movable end plate 4 and the flange portion 18a of the heat pipe 18 so as to communicate the inner peripheral side of the bellows 17 and the outside air side.

  The adjustment nut 14 is provided with a female screw portion 14a that is screwed into the male screw portion 19a of the adjustment screw 19, and a hole 14b having a larger diameter than the female screw portion 14a. A stop screw is provided between the female screw portion 14a and the hole 14b. A step portion 14c to which the 16 head portions 16a can be engaged is formed. Further, bearings 22 and 23 are provided between the heat pipe 18 and the adjusting nut 14, a female screw portion 19b is provided at the lower end of the adjusting screw 19, and a stop screw 16 is screwed into the female screw portion 19b. Other configurations are the same as those of the prior art.

  In the above configuration, the adjustment of the maximum capacitance value is the same as the conventional one. The capacitance is adjusted by rotating the adjustment nut 14, moving the adjustment screw 19 and the movable electrode support plate 9 up and down, and moving the movable electrode 10 up and down.

In the first embodiment, by eliminating the center pin, heat generated by energization of the center pin and heat generated by sliding can be eliminated, the internal loss can be reduced, and the energization capability can be improved. Further, a linear bearing 20 as a sliding portion is provided between the fixed side heat pipe 18 and the movable side adjustment screw 19, and bearings 22 and 23 are provided between the heat pipe 18 and the adjustment nut 14. In addition, the resistance to the radial load of the adjusting nut 14 can be improved, the sliding torque can be reduced, and the rotational torque of the adjusting nut 14 can also be reduced. Further, a heat pipe 18 and a heat radiation guide 21 are provided between the inner peripheral side of the bellows 17 and the linear bearing 20, and air holes 4 b and 18 b for heat radiation of the bellows 17 are provided in the movable side end plate 4 and the heat pipe 18. The heat generated by the bellows 17 does not adversely affect the linear bearing (sliding portion) 20 and the like, does not adversely affect the sliding of the adjusting screw 19 and the rotation of the adjusting nut 14, and can improve the cooling efficiency of the bellows 17. By increasing it, it is also possible to increase the current carrying capacity.

  In the first embodiment, the air holes 4b and 18b are provided in the fixed side end plate 4 and the heat pipe 18. However, if the inner peripheral side of the bellows 17 and the outside air can be communicated, the air hole is movable side end. You may provide only in the board 4 or only in the heat pipe 18. FIG.

Embodiment 2
FIG. 2 is a cross-sectional view of the vacuum variable capacitor according to the second embodiment, and 24 is a screw receiving portion erected on the inner peripheral side of the hole 4a of the movable side end plate 4 on the inner peripheral side of the bellows 17, The adjusting screw 13 having the upper end attached to the movable lead 11 is inserted into the screw receiving portion 24. Further, the upper end of the adjustment nut 14 is rotatably supported by the screw receiving portion 24 via the bearing 15. Further, on the outer peripheral side of the bellows 17 in the vacuum vessel 5, a bypass energization unit 25 that energizes between the movable electrode support plate 9 and the movable side end plate 4 is provided. The bypass energization unit 25 includes a cylindrical conductor portion 25a attached to the movable electrode support plate 9, a cylindrical conductor portion 25b attached to the movable side end plate 4, and a flexible flexible member that connects the two. The bypass energizing portion 25 is made of copper having good electrical conductivity. Further, a reinforcing plate 26 is attached to the outer surface side of the movable side end plate 4, an insertion hole 26a is provided at the center of the reinforcing plate 26, and the adjustment nut 14 and the like are inserted into the insertion hole 26a. Other configurations are the same as those of the prior art.

  Also in the second embodiment, the movable electrode 10 is moved up and down through the adjustment screw 13 and the movable lead 11 by the rotation of the adjustment nut 14 to adjust the capacitance.

  In the second embodiment, the bypass energization unit 25 is provided on the outer periphery of the bellows 17, and the energization on the fixed side and the movable side is performed by the bypass energization unit 25, so that a large current energization is possible. Further, the bellows 17 is provided only for distinguishing between the vacuum side and the atmosphere side, and the diameter can be reduced. For this reason, the vacuum variable capacitor does not increase in size, and the self-closing force resulting from the pressure difference between the vacuum side and the atmosphere side is reduced, and the rotational torque of the adjusting nut 14 can be reduced.

  Although the bypass energizing portion 25 is formed of copper, it may be formed of silver having good electrical conductivity, or may be formed of a stainless steel coated with copper or a stainless steel coated with silver.

Embodiment 3
FIG. 3 is a cross-sectional view of the vacuum variable capacitor according to the third preferred embodiment. Reference numeral 24 denotes a screw receiving portion fitted in the hole 4a of the movable side end plate 4 on the inner peripheral side of the bellows 17, and the screw receiving portion 24 is The upper end of the adjusting nut 14 is rotatably supported via the bearing 15. A heat pipe 27 is erected on the inner surface of the bellows 17 on the inner surface of the movable end plate 4 on the outer periphery of the screw receiving portion 24. The movable side end plate 4 and the reinforcing plate 26 are provided with air holes 4b and 26b that communicate the inner peripheral side of the bellows 17 with the outside air side. Other configurations are the same as those in the conventional and the above-described best embodiments.

  In the third embodiment, since the air holes 4b and 26b that communicate the inner peripheral side and the outside air side of the bellows 17 are provided, the cooling effect of the bellows 17 that generates heat by energization is increased, and a large current can be achieved. . Further, since the heat pipe 27 is provided, the member on the inner peripheral side can be protected from the heat of the bellows 17, and this can also increase the current.

Embodiment 4
FIG. 4 is a cross-sectional view of a vacuum variable capacitor according to the fourth embodiment, and FIGS. 5A and 5B are a partial plan view and a partially developed perspective view of the sliding contact, respectively, and the center pin 7 is not provided. The insulating cylinder 30 is made of ceramics, but is made of high-purity alumina with particularly low dielectric loss (tan δ). Specifically, alumina having a purity of 92% is usually used, whereas high purity alumina has a purity of 99.5% or more. 28 is a heat pipe formed on the inner peripheral side of the bellows 17 with a flange portion 28a attached to the outer surface side of the peripheral portion of the hole 4a of the movable side end plate 4 and protruding inward of the vacuum vessel 5. 28 is made of a conductive material and also functions as a sliding guide. Reference numeral 29 denotes an adjustment screw having an upper end attached to the movable electrode support plate 9 and slidably inserted into the heat pipe 28. A male screw portion 29a is provided on the outer periphery of the lower end side, and a female screw portion 29b is provided on the lower end. It is done.

  Reference numeral 31 denotes a cylindrical sliding member whose upper end is attached to the movable electrode support plate 9 on the inner peripheral side of the bellows 17. The sliding member 31 is made of a conductive material such as copper and slides with the heat pipe 28. A sliding contact 32 made of copper or the like is provided at a sliding portion of the heat pipe 28 with the sliding member 31. The stop screw 16 is screwed into the female screw portion 29b of the adjustment screw 29, and the adjustment nut 14 is rotatably supported on the inner peripheral side of the heat pipe 28 via bearings 22 and 23. The adjustment nut 14 has a female screw portion 14 a that is screwed with the male screw portion 29 a of the adjustment screw 29, and has a step portion 14 c that can be engaged with the head portion 16 a of the stop screw 16. The movable end plate 4 and the flange portion 28 a of the heat pipe 28 are provided with air holes 4 b and 28 b communicating the inner peripheral side of the bellows 17 and the outside air side.

In the fourth embodiment, since the center pin is not provided, no heat is generated due to the energization and no heat is generated due to the sliding friction, and the insulating cylinder 30 is made of high-purity alumina, and the dielectric loss is small. Reduced. Therefore, the internal loss is reduced and the current carrying capacity can be improved. In addition, since the energization of the fixed side and the movable side is performed through the sliding member 31, the sliding contact 32, and the heat pipe 28, the current can be increased as compared with the case where the energization is performed by the bellows 17. The diameter can be reduced and the size can be reduced. In addition, since the heat pipe 28 has a function as a sliding guide and the bearings 22 and 23 are provided between the heat pipe 28 and the adjustment nut 14, the adjustment can be performed even if a lateral load is applied to the adjustment nut 14. There is no hindrance to the rotation of the nut 14 and the sliding of the adjusting screw 29. further,
By providing the air holes 4b and 28b, the cooling effect of the bellows 17 can be enhanced, and by providing the heat pipe 28, adverse effects on the sliding portion due to the heat of the bellows 17 can be prevented.

It is sectional drawing of the vacuum variable capacitor by Embodiment 1 of this invention. It is sectional drawing of the vacuum variable capacitor by Embodiment 2 of this invention. 6 is a cross-sectional view of a vacuum variable capacitor according to Embodiment 3. FIG. It is sectional drawing of the vacuum variable capacitor by Embodiment 4. It is the partial top view and partial expansion | deployment perspective view of the sliding contact by Embodiment 4. It is sectional drawing of the conventional vacuum variable capacitor. It is the equivalent circuit of the conventional vacuum variable capacitor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,30 ... Insulating cylinder 2 ... Fixed side end plate 4 ... Movable side end plate 4a ... Hole 4b, 18b, 26b, 28b ... Air hole 5 ... Vacuum container 6 ... Fixed electrode 7 ... Center pin 9 ... Movable electrode support plate 10 ... Moving electrode 11 ... Moving lead 13,19,29 ... Adjusting screw 13a, 19a, 29a ... Male screw part 13b, 14a, 19b, 29b ... Female screw part 14 ... Adjusting nut 14c ... Step part 15,22,23 ... Bearing 16 ... Stop screw 16a ... Head 17 ... Bellows 18, 27, 28 ... Heat pipe 20 ... Linear bearing 21 ... Radiation guide 24 ... Screw receiving part 25 ... Bypass energizing part 26 ... Reinforcing plate 31 ... Sliding member 32 ... Sliding contact

Claims (5)

  A vacuum vessel in which both ends of the insulating cylinder are closed by a fixed side end plate and a movable side end plate, a fixed electrode standing on the inner surface of the fixed side end plate, and a fixed side end plate disposed in the vacuum vessel. A movable electrode support plate, a movable electrode erected on the fixed side end plate side of the movable electrode support plate so as to face the fixed electrode, one end is attached to the movable electrode support plate, and the other end is connected to the movable side end plate A cylindrical bellows that is attached and separates the vacuum side and the atmosphere side, a heat pipe that protrudes inwardly from the hole of the movable side end plate on the inner peripheral side of the bellows, and one end that is on the movable electrode support plate An adjustment screw that is attached and inserted into the heat pipe and has a male screw portion provided on the outer periphery on the other end side, and a female screw portion formed on the other end, a stop screw that engages with the female screw portion of the adjustment screw, and a heat Via a bearing on the inner periphery of the pipe An adjustment nut that is supported rotatably and has an internal thread portion that engages with the external thread portion of the adjustment screw and a step portion that can engage with the head portion of the stop screw, and a movable electrode support plate on the inner peripheral side of the bellows A vacuum variable capacitor, comprising: a heat radiation guide that is attached and covers an outer periphery of the heat pipe; and an air hole that communicates the inner periphery side and the outside air side of the bellows.   2. The vacuum variable capacitor according to claim 1, wherein a linear bearing is provided at a sliding portion with the adjustment screw of the heat pipe. A vacuum vessel in which both ends of the insulating cylinder are closed by a fixed-side end plate and a movable-side end plate, a fixed electrode erected on the inner surface of the fixed-side end plate, and a center pin erected at the center of the inner surface of the fixed-side end plate; A movable electrode support plate disposed in the vacuum container facing the fixed side end plate, a movable electrode standing on the fixed side end plate side of the movable electrode support plate facing the fixed electrode, and one end movable Attached to the electrode support plate, the other end is attached to the movable side end plate, a cylindrical bellows that separates the vacuum side and the atmosphere side, and attached to the movable electrode support plate on the inner peripheral side of the bellows, A movable lead that is slidably fitted and insulated from the center pin, a screw receiving portion provided in a hole of the movable side end plate on the inner peripheral side of the bellows, and one end attached to the movable lead, and a screw receiving portion Inserted into An adjustment screw having a male screw portion on the outer periphery and a female screw portion formed on the other end, a stop screw that engages with the female screw portion of the adjustment screw, and a screw receiving portion that is rotatably supported via a bearing An adjustment nut having a female threaded portion that engages with the male threaded portion of the adjusting screw, and a stepped portion that can be engaged with the head of the stop screw, and a movable side end plate on the outer peripheral side of the screw receiving portion on the inner peripheral side of the bellows. A vacuum variable capacitor comprising an attached heat pipe and an air hole that communicates an inner peripheral side and an outside air side of the bellows . A vacuum vessel where the both ends of the insulating tube is closed by a fixed side end plate and the movable side end plate, a fixed electrode provided upright on the inner surface of the fixed end plate, is disposed opposite to the fixed end plate to the vacuum vessel The movable electrode support plate, the movable electrode standing on the fixed side end plate side of the movable electrode support plate, facing the fixed electrode, one end is attached to the movable electrode support plate, and the other end is the movable side end plate A cylindrical bellows that separates the vacuum side and the atmosphere side, and a conductive material that is provided inwardly projecting into the hole of the movable side end plate on the inner peripheral side of the bellows and also serves as a sliding guide A heat pipe, an adjustment screw having one end attached to the movable electrode support plate, slidably inserted into the heat pipe, and provided with a male screw portion on the outer periphery of the other end and a female screw portion formed on the other end , the movable electrode supporting the inner circumferential side of the bellows Attached to the plate, a conductive material for the heat pipe and the sliding
A sliding member made of a conductive material provided in a sliding portion between the sliding member and the heat pipe, a stop screw screwed into the female screw portion of the adjusting screw, and an inner peripheral side of the heat pipe An adjustment nut that is rotatably supported through a bearing and has a female screw portion that engages with a male screw portion of the adjustment screw, and a step portion that can engage with a head portion of a stop screw, an inner peripheral side of the bellows, and an outside air A vacuum variable capacitor comprising an air hole communicating with the side. The vacuum variable capacitor according to claim 1, wherein the insulating cylinder is made of high-purity alumina .

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