JP2008098329A - Vacuum capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To correctly set capacitance between a fixed electrode and a movable electrode to an arbitrary value, to perform desired impedance adjustment, and to miniaturize a vacuum capacitor. <P>SOLUTION: The capacitance between the fixed electrode 4 and movable electrode 5 is changed by moving a movable rod 6 extending from the movable electrode 5 of the vacuum capacitor by means of an ultrasonic motor 10. The ultrasonic motor 10 comprises: a piezoelectric ceramics member 10d that electrically oscillates by the application of a high frequency voltage; an elastic lamination member 10e that is laminated on the piezoelectric ceramics member 10d, and bends according to the oscillation of the piezoelectric ceramics member 10d; a rotor member 10g that is pressure-welded to the elastic lamination member 10e and rotates according to the bending of the elastic lamination member 10e; and an output axis 10a that rotates together with the rotor member 10g and is coupled with the movable rod 6. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vacuum capacitor, for example, a vacuum capacitor used for impedance adjustment in a high-frequency device such as a high-frequency power source of a semiconductor facility or a high-power transmission circuit.

Conventionally, various vacuum capacitors (for example, Patent Document 1) have been used for impedance adjustment in a high-frequency device such as a high-frequency power source of a general semiconductor facility or a large power transmission circuit.
FIG. 3 is a schematic explanatory view showing an example of a general vacuum capacitor (variable vacuum capacitor). In FIG. 3, reference numeral 1 denotes a vacuum container for filling a high-strength vacuum dielectric material. The vacuum vessel main body 2 provided with the flanges 2b and 2c, and the metal end plates 3a and 3b provided so as to seal (close) both ends of the vacuum vessel main body 2 and also function as external terminals (Hereinafter, the fixed electrode side described later is referred to as a fixed conductor and the other is referred to as a sealed end plate).

  Reference numeral 4 denotes a fixed electrode formed by concentrically arranging a plurality of substantially cylindrical electrode members having different inner diameters at regular intervals and provided inside the vacuum vessel 1 of the fixed conductor 3a. Reference numeral 5 denotes a configuration in which a plurality of substantially cylindrical electrode members having different inner diameters are concentrically spaced apart from each other in the same manner as the fixed electrode 4 and the electrode members are fixed to the fixed electrode 4 in a non-contact state. The movable electrode provided inside the vacuum vessel 1 is shown so that it can be inserted into and removed from the electrode 4 (inserted between the electrode members of the fixed electrode 4 and crossed over each other). The movable electrode 5 is provided on a conductor (hereinafter referred to as a movable conductor) 5 a that is movable in the axial direction of the vacuum vessel 1 (movable so that the degree of insertion / removal with respect to the fixed electrode 4 can be adjusted).

  Reference numeral 6 extends in the axial direction of the vacuum vessel 1 from the back side of the movable conductor 5a (the side where the fixed electrode 4 is not provided) (in the figure, protrudes from the sealed end plate 3b side of the vacuum vessel 1). The movable rod extended in this manner (in the figure, a hollow movable rod) is shown, for example, provided in the vacuum vessel 1 (in the figure, fixed at a substantially central portion of the sealing end plate 3b). The bearing member 6a is slidably supported (the side surface of the movable rod 6 is slidable on the bearing member 6a (slidable in the axial direction of the vacuum vessel 1)).

  Reference numeral 7 indicates a rod for moving the movable rod 6 in the axial direction of the vacuum vessel 1 and adjusting the electrostatic capacity of the vacuum capacitor for insulation operation (hereinafter referred to as an insulation operation rod). One end side (the side where the male screw portion 7b is formed in the drawing) is screwed to one end side of the movable rod (in the drawing, screwed to the female screw portion 6b formed on the inner wall on the one end side of the movable rod). The other end side (the side where the head portion 7a is formed in the figure) is joined with a driving source (such as a motor) of a vacuum capacitor. The insulating operating rod 7 is provided in, for example, the vacuum vessel 1 (fixed so as to cover the bearing member 6a protruding from the sealed end plate 3b in the drawing) (screw receiving in the drawing). (Supporting body comprising a portion 8a and a thrust bearing 8b for reducing the rotational torque).

  Reference numeral 9 denotes a soft metal bellows, which is configured such that the movable electrode 5, the movable conductor 5 a, and the movable rod 6 can move in the axial direction of the vacuum vessel 1 while keeping the inside of the vacuum vessel 1 airtight. Is joined to the inner wall side of the sealing end plate 3b and the bearing member 6a, and the other edge is joined to the movable conductor 5a. Various types of bellows 9 are known. For example, a structure in which the edge of the other end of the bellows 9 is joined to the surface of the movable rod 6, or a structure in which the bellows 9 itself is doubled. There are also (for example, a structure in which a stainless bellows and a copper bellows are combined).

  In the vacuum capacitor configured as described above, when the insulating operation rod 7 is rotated by a driving source such as a motor, the movable rod 6 moves in the axial direction of the vacuum vessel 1 along with the rotation, and is fixed. The cross area of the electrode 4 and the movable electrode 5 changes. As a result, when voltages having different polarities are applied to the electrodes 4 and 5, the value of the capacitance generated between the electrodes 4 and 5 is continuously adjusted, and impedance adjustment is performed. Has been. With respect to the high-frequency current for the high-frequency device in the case of using such a vacuum capacitor, the sealed end is connected via the electrostatic capacitance between the fixed conductor 3a to the bellows 9 and the counter electrode (between the fixed electrode 4 and the movable electrode 5). It flows from the board.

  However, in the case of a vacuum capacitor having a configuration as shown in FIG. 3, the movement of the movable rod in the axial direction of the vacuum vessel is restrained at an arbitrary position (for example, an operation of stopping the movable rod by stopping driving by a motor or the like) However, a tensile force (a force that pulls the movable rod in the direction toward the inside of the vacuum vessel (the direction indicated by the arrow Y in the drawing)) acts on the movable rod due to the vacuum pressure existing in the vacuum vessel. It was difficult to quickly stop the movement of the movable rod (for example, instantaneously stop the rotation of the output shaft of a motor or the like).

  That is, even if it tries to stop the movement of the movable rod as described above, the movable rod may continue to move according to the tensile force, and the capacitance cannot be set to an arbitrary value. There is a risk that impedance adjustment different from the intended one may be performed.

  Therefore, in order to quickly stop the movement of the movable rod, a device for instantaneously braking the driving force against a driving source such as a motor (for example, stopping rotation of an output shaft of a motor or the like) Although a means for configuring the brake device (referred to as an output shaft of a motor or the like) is considered, the shape of the vacuum capacitor is large by the brake device (for example, larger than the output shaft direction of the motor). As a result, an increase in the size of the vacuum capacitor could not be avoided. In addition to the braking device, a gear device or the like needs to be provided (for example, an output shaft of a motor or the like), which may further increase the size.

  The present invention has been made on the basis of the above-mentioned problems, and it is possible to accurately set the capacitance between the fixed electrode and the movable electrode with an arbitrary value to perform desired impedance adjustment, and to reduce the size ( For example, it is an object of the present invention to provide a vacuum capacitor that can be reduced in size as compared with a conventional vacuum capacitor using a braking device or a gear device related to a movable rod.

  In order to solve the above-mentioned problems, the invention according to claim 1 is characterized in that a vacuum vessel formed by closing at least part of both ends of a cylindrical body having insulating properties with metal members, A fixed electrode disposed on one metal member side in the vacuum container, and a movable electrode disposed so as to form a capacitance between the other metal member side in the vacuum container and the fixed electrode; A movable rod extending from the back side of the movable electrode to the outside of the vacuum vessel, and a drive source for moving the movable rod so as to change a capacitance between the movable electrode and the fixed electrode, The driving source includes a piezoelectric ceramic member that is electrically vibrated by application of a high-frequency voltage, an elastic laminated member that is laminated on the piezoelectric ceramic member and bends according to the vibration of the piezoelectric ceramic member, A rotor member that is in pressure contact with the elastic laminate member and rotates by bending of the elastic laminate member, and an output motor that rotates together with the rotor member and is connected to a movable rod. And

  According to a second aspect of the present invention, in the first aspect of the present invention, the rotor member is pressed against the elastic laminated member in a direction in which the tensile force acts by a tensile force in a vacuum vessel.

  A third aspect of the invention is characterized in that, in the first aspect of the invention, the rotor member is pressed against the elastic laminate member by a biasing member on a tensile force reaction side.

  According to the vacuum capacitor as in the present invention, since the rotor member that rotates together with the output shaft of the ultrasonic motor is pressed against the elastic laminated member, if the driving force of the ultrasonic motor itself is eliminated, the elastic laminated member and The frictional force between the rotor member and the rotor member restrains the movement of the rotor member, the output shaft, and the movable rod.

  As described above, according to the present invention, the capacitance between the fixed electrode and the movable electrode can be accurately set to an arbitrary value without using a movable rod braking device or gear device as in the conventional vacuum capacitor. In a technical field related to impedance adjustment in a high-frequency device such as a high-frequency power source of a semiconductor facility or a high-power transmission circuit, for example, the vacuum capacitor can be miniaturized. It is possible to contribute.

  Hereinafter, a vacuum capacitor according to an embodiment of the present invention will be described in detail with reference to the drawings.

  In the present embodiment, the fixed electrode disposed in the vacuum container, the movable electrode disposed so as to form a capacitance between the fixed electrode, and the back surface of the movable electrode extend outside the vacuum container. A vacuum capacitor equipped with a movable rod, and an ultrasonic motor is applied as a drive source for moving the movable rod, and the capacitance between the movable electrode and the fixed electrode is accurately set at an arbitrary value. It is characterized by doing.

  The ultrasonic motor includes a piezoelectric ceramic member that vibrates electrically upon application of a high-frequency voltage, an elastic laminated member that is laminated on the piezoelectric ceramic member and bends according to the vibration of the piezoelectric ceramic member, and the elastic laminated member. A rotor member that is pressed and rotated by bending of the elastic laminated member, and an output shaft that rotates together with the rotor member and is connected to a movable rod is applied.

[Example 1]
FIG. 1 is a schematic explanatory view showing an example of a vacuum capacitor in the present embodiment. Note that the same components as those shown in FIG. 3 are denoted by the same reference numerals, and detailed description thereof is omitted as appropriate.

  In the vacuum capacitor shown in FIG. 1, reference numeral 10 denotes an ultrasonic motor. For example, a support member fixed to one end side of the vacuum vessel 1 (a support member fixed to the sealing end plate 3b in the figure). 11, the output shaft 10a of the ultrasonic motor 10 is connected to one end side of the insulating operating rod 7 (connected to the head 7a in the drawing) via the connecting means 7c.

  The ultrasonic motor 10 includes a stator member 10c that is fixed to the support member 11 and has a through hole 10b for the output shaft 10a, and a piezoelectric ceramic member that is provided on the stator member 10c in a ring shape that covers the outer peripheral side of the output shaft 10a. 10d and a ring shape similar to that of the piezoelectric ceramic member 10d, and a substantially comb-like groove is formed on the surface (the surface on which the rotor member described later is pressed), and the piezoelectric ceramic member 10d (in the drawing, piezoelectric) In the ceramic member 10d, a member (hereinafter referred to as an elastic laminated member) 10e laminated on a side opposite to the direction in which the tensile force acts (hereinafter referred to as a tensile force reaction side) 10e, and a biasing member (in the drawing) An urging force of a leaf spring 10f provided in the output shaft 10a and urged in the same direction as the acting direction of the tensile force (in the drawing, acts in the same direction as the tensile force, and will be described later. And the rotor member 10g to rotate along with Pressed output shaft 10a to the elastic laminate member 10e by the biasing force of the tensile sized such that the extent that may be against the force of) power, and a.

  The support member 11 includes a support plate 11a fixed to the sealing end plate 3b, and a support column 11b provided on the support plate 11a on the outer peripheral side of the output shaft 10a (a plurality of support pillars 11b are provided in the drawing). And fixed to the support plate 11a via the support column 11b (in the drawing, a bolt is passed through the support column 11b from the outer peripheral side of the mounting plate 11c and screwed to the support plate 11a), and the ultrasonic motor 10 is attached. And a mounting plate 11c.

  In the ultrasonic motor 10 configured as described above, when a high frequency voltage is first applied to the piezoelectric ceramic member 10d, the piezoelectric ceramic member 10d itself vibrates electrically due to an electrostriction phenomenon. At this time, the elastic laminated member 10e bends in the direction of the output shaft 10a according to the electric vibration force, and a traveling wave due to the bending moves along the circumferential direction of the elastic laminated member 10e. Thus, the rotor member 10g and the output shaft 10a rotate. As a result, the insulating operation rod 7 connected to the output shaft 10a rotates (rotates together with the output shaft 10a), and the movable rod 6 screwed to one end portion of the insulating operation rod 7 has the shaft. The capacitance between the fixed electrode 4 and the movable electrode 5 is changed by moving in the direction (that is, the movable electrode 5 is moved).

  After changing the capacitance as described above, when the application of the high frequency voltage to the piezoelectric ceramic member 10d is stopped and the driving force of the ultrasonic motor 10 itself is removed, the elastic laminated member 10e and the elastic laminated member 10e are removed. The movable rod 6 is moved along with the rotation of the rotor member 10g, the output shaft 10a, and the insulating operation rod 7 by the frictional force between the rotor member 10g and the rotor member 10g pressed against the rotor member 10g (frictional force accompanying the biasing force of the biasing member 10f). Is stopped.

  That is, since there is always a frictional force accompanying the biasing force of the biasing member 10f between the elastic laminated member 10e and the rotor member 10g, even if there is a tensile force in the vacuum vessel 1 (and The movable rod 6 that has moved as described above does not use the high-frequency voltage applied to the piezoelectric ceramic member 10d (even without using a braking device or gear device for the ultrasonic motor 10 as in the prior art). , Quickly stopped.

  Therefore, by configuring the vacuum capacitor as in this embodiment, the size can be reduced and the capacitance can be adjusted as compared with the conventional vacuum capacitor using a braking device or a gear device. Can be performed more accurately.

  In the present embodiment, the direction of action of the tensile force Y in the vacuum vessel 1 is the same as the direction of action of the urging force Y of the urging member 10f, so that the tensile force Y can be used without using the urging member 10f. If a sufficient frictional force is generated between the elastic laminated member 10e and the rotor member 10g, the capacitance can be adjusted more accurately in the same manner as in this embodiment, and the size can be further reduced (attached). It is also possible to reduce the size by omitting the force member 10f.

[Example 2]
FIG. 2 is a schematic explanatory view showing another example of the vacuum capacitor in the present embodiment. In addition, about the thing similar to what was shown in FIG. 1, detailed description is abbreviate | omitted suitably using the same code | symbol.

  In the vacuum capacitor of FIG. 2, the ultrasonic motor 10 having the same configuration as that of FIG. 1 is located in the support member 11, and the elastic laminated member 10e is disposed on the side of the tensile force Y acting direction than the piezoelectric ceramic member 10d. The urging force of the urging member (the leaf spring provided on the output shaft 10a in the drawing) 10f (the urging force that acts on the reaction side of the tensile force in the drawing and can resist the tensile force Y) ), The rotor member 10g is pressed against the elastic laminated member 10e.

  According to the vacuum capacitor thus configured, as in the first embodiment, first, by applying a high frequency voltage to the piezoelectric ceramic member 10d, the elastic laminated member 10e is caused by the electrostriction phenomenon of the piezoelectric ceramic member 10d itself. The rotor member 10g, the output shaft 10a, and the insulating operation rod 7 rotate and the movable rod 6 moves due to the deflection, and the electrostatic capacitance between the fixed electrode 4 and the movable electrode 5 changes.

  Further, even after changing the capacitance as described above, as in Example 1, when the application of the high frequency voltage to the piezoelectric ceramic member 10d is stopped and the driving force of the ultrasonic motor 10 itself is eliminated, Due to the frictional force between the elastic laminated member 10e and the rotor member 10g (the frictional force accompanying the urging force of the urging member 10f), the rotor member 10g, the output shaft 10a, the insulating operation rod 7 and the movable rod 6 are rotated. Movement is stopped.

  That is, the frictional force accompanying the urging force of the urging member 10f always exists between the elastic laminated member 10e and the rotor member 10g, so even if the tensile force Y exists in the vacuum vessel 1 ( In addition, the movable rod 6 that has moved as described above has stopped applying the high-frequency voltage to the piezoelectric ceramic member 10d without using a braking device or gear device for the ultrasonic motor 10 as in the prior art. Later, it is stopped immediately.

  Therefore, by configuring the vacuum capacitor as in the present embodiment, the vacuum capacitor can be reduced in size as in the first embodiment, and the capacitance can be adjusted more accurately. Further, as shown in FIG. 2, in the case of a vacuum capacitor in which the urging force of the urging member 10f acts on the tensile force reaction side, the urging force necessary to counter the tensile force Y is shown in FIG. Since it can be made smaller than in the case of a vacuum capacitor, it is possible to apply the ultrasonic motor 10 having a smaller capacity. Furthermore, since the ultrasonic motor 10 itself is housed in the support member 11, damage due to external factors (for example, impact from the outer periphery of the vacuum capacitor) is suppressed more than the vacuum capacitor shown in FIG. Is possible.

  Even in the structure in which the ultrasonic motor 10 is located in the support member 11 as in the present embodiment, the elastic laminated member from the tensile force reaction side of the piezoelectric ceramic member 10d with respect to the piezoelectric ceramic member 10d as in the first embodiment. 10e and the rotor member 10g are laminated, and a sufficient frictional force is generated between the elastic laminated member 10e and the rotor member 10g by the tensile force Y without using the biasing member 10f. Similarly, the capacitance can be adjusted more accurately, and further downsizing (downsizing by omitting the biasing member 10f) can be achieved.

  Although the present invention has been described in detail only for the specific examples described above, it is obvious to those skilled in the art that various changes and modifications are possible within the scope of the technical idea of the present invention. Such variations and modifications are naturally within the scope of the claims.

  For example, if the capacitance between the fixed electrode and the movable electrode can be changed according to the movement of the movable rod by the ultrasonic motor, the fixed electrode, the movable electrode, the movable rod, the insulating operation rod, the support The members and the like can be applied in various shapes, and may be omitted as appropriate (for example, the support member and the insulating operation rod are omitted as appropriate).

Schematic explanatory drawing which shows an example of the vacuum capacitor in this Embodiment. Schematic explanatory drawing which shows the other example of the vacuum capacitor in this Embodiment. Schematic explanatory drawing of a general vacuum capacitor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Vacuum container 2 ... Vacuum container main body 3a, 3b ... End plate 4 ... Fixed electrode 5 ... Movable electrode 6 ... Movable rod 7 ... Insulation operation rod 8 ... Support body 9 ... Bellows 10 ... Ultrasonic motor 10a ... Output shaft 10b ... Through hole 10c ... Stator member 10d ... Ceramics member 10e ... Elastic laminated member 10f ... Biasing member 10g ... Rotor member 11 ... Support member

Claims (3)

A vacuum vessel formed by closing both ends of a cylindrical body having at least a part of insulation with a metal member;
A fixed electrode disposed on one metal member side in the vacuum vessel;
A movable electrode arranged to form a capacitance between the other metal member in the vacuum vessel and the fixed electrode;
A movable rod extending from the back side of the movable electrode to the outside of the vacuum vessel;
A vacuum source comprising a drive source for moving the movable rod to change the capacitance between the movable electrode and the fixed electrode,
The drive source includes a piezoelectric ceramic member that vibrates electrically when a high-frequency voltage is applied;
An elastic laminated member that is laminated on the piezoelectric ceramic member and bends according to the vibration of the piezoelectric ceramic member;
A rotor member pressed against the elastic laminated member and rotated by bending of the elastic laminated member;
A vacuum capacitor comprising an ultrasonic motor having an output shaft that rotates together with the rotor member and is connected to a movable rod.   2. The vacuum capacitor according to claim 1, wherein the rotor member is pressed against the elastic laminated member in a direction in which the tensile force acts by a tensile force in a vacuum vessel.   2. The vacuum capacitor according to claim 1, wherein the rotor member is pressed against the elastic laminate member on the side opposite to the tensile force reaction by a biasing member.

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