JPH06267793A - Variable capacitor - Google Patents

Abstract

PURPOSE:To provide a large capacitance without the strength of a stator lowered and at the same time to simplify the manufacturing process to reduce a manufacturing cost. CONSTITUTION:This variable capacitor is provided with a stator 2 in which a stator electrode 1 is formed inside and an external electrode 7a electrically connected to the stator electrode 1 is formed outside, a rotor 3 rotatably mounted on the stator 2, a spring member 4 provided on the upper surface side of the rotor 3 to press the rotor 3 against the stator 2, a rotor lead-out electrode 5 electrically in continuity to the rotor 3 and a shaft 11 which passes through the stator 2 and the rotor 3 and also is engaged with the rotor 3 in such a manner that the rotor 3 rotates together therewith and at the same time is engaged with the spring member 4, thereby being held so as to be able to slide and rotate with the rotor 3 being pressed against the stator 2 with the elastic force thereof, in the lower-side end surface of which a driver groove 14 is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a capacitor,
More specifically, the present invention relates to a variable capacitor capable of adjusting a minute electrostatic capacitance.

[0002]

2. Description of the Related Art As a conventional variable capacitor capable of adjusting a minute electrostatic capacity, for example, a real fair 3-9.
There is a variable capacitor disclosed in Japanese Patent No. 318. Figure 7
As shown in FIG. 3, in this variable capacitor, a metal shaft 52 extending vertically is arranged in a case 51 made of an insulating material having an opening on the upper surface,
With the shaft 52 penetrating therethrough, a dielectric plate 53 having a stator electrode (not shown) is fixedly arranged on the lower surface side, and a metal rotor 54 is rotatably arranged on the dielectric plate 53.

A spring piece 55 is arranged on the upper surface of the metal rotor 54, and the spring piece 55 is attached to the case 51.
The metal rotor 54 is slidably pressed against the dielectric plate 53 by being pressed by the driver grooved spring 56 disposed on the upper surface side of the.

Then, the metal rotor 54 is rotated by engaging the tip of a driver (not shown) with the driver groove 57 and rotating the driver.
And the size of the electrostatic capacitance formed between the stator electrode (not shown) formed on the lower surface side of the dielectric plate 53 can be adjusted.

Further, a driver groove 58 is also formed on the lower end surface of the shaft 52, and a driver (not shown) is engaged with the driver groove 58 to allow the shaft 5 to move from the lower surface side.
It is configured so that the metal rotor 54 can be rotated together by rotating 2 to adjust the magnitude of the electrostatic capacitance.

A stator-side terminal (metal terminal) 59 which is electrically connected to the stator electrode is provided in the lower part of the case 51.
The rotor-side terminal (metal terminal) 60, which is electrically connected to the metal rotor 54 via the shaft 52 and the spring piece 55, is
It is arranged so as to wrap around from the side surface to the lower surface side, and the electrostatic capacitance is taken out by the stator side terminal 59 and the rotor side terminal 60.

[0007]

However, in the above conventional variable capacitor, the stator electrode (not shown) is formed on the lower surface of the dielectric plate 53, and the electrostatic capacitance is provided between the stator electrode and the metal rotor 54. Therefore, in order to obtain a large capacitance, it is necessary to reduce the thickness of the dielectric plate 53 between the stator electrode and the metal rotor 54. However, when a dielectric plate made of a ceramic dielectric is used as the dielectric plate 53, its mechanical strength is relatively low, and therefore there is a limit to reducing the thickness of the dielectric plate 53, resulting in a large capacity or a small size. There is a problem that conversion is limited.

Further, in the above conventional variable capacitor, the stator side terminal (metal terminal) 59 and the rotor side terminal (metal terminal) are arranged in the case 51 by, for example, a method such as insert molding. There is a problem that the thickness of the lower part of 51 becomes large, and the size of the variable capacitor as a whole becomes large.

Further, the case 51 and the stator side terminal 59
Therefore, there are problems that the number of parts is increased, the manufacturing process is complicated, and the manufacturing cost is increased.

The present invention solves the above-mentioned problems, and it is possible to obtain a large electrostatic capacity without lowering the strength of the stator and it is possible to cope with miniaturization, and the number of parts is also increased. It is an object of the present invention to provide a variable capacitor capable of simplifying the manufacturing process and reducing the manufacturing cost by reducing.

[0011]

In order to achieve the above object, a variable capacitor of the present invention has a stator electrode formed therein which functions as a fixed-side electrode, and is externally electrically connected to the stator electrode. A stator made of a ceramic dielectric having electrodes formed thereon and rotatably mounted on the stator, made of metal or having an electrode formed on at least a part of an insulator, which functions as a movable electrode. A rotor, a spring member arranged on the upper surface side of the rotor for pressing the rotor into pressure contact with the stator, a rotor extraction electrode electrically connected to the rotor (movable side electrode), and penetrating at least the stator and the rotor, Also, the rotor is engaged with the rotor in such a manner as to rotate together, and is engaged with the spring member so that the elastic force causes Holding the over data slidably rotate while being pressed against the stator, characterized by comprising a shaft driver grooves are formed on the lower end surface.

[0012]

In the variable capacitor according to the present invention, the stator electrode and the rotor (in the case of the rotor in which an electrode is formed on a part of the insulator, the rotor electrode) function as a fixed side electrode and a movable side electrode and are adjustable. An electrostatic capacitance is formed between the two, and this electrostatic capacitance is taken out by the external electrode of the stator and the rotor extraction electrode (or the external electrode connected to the rotor extraction electrode).

Further, in the variable capacitor of the present invention, since the stator electrode is formed inside the stator (dielectric), the thickness of the entire stator is increased while the stator electrode and the rotor (movable side electrode) are Since the thickness of the dielectric layer between them can be reduced, a large capacitance can be obtained without reducing the strength of the stator.

Further, since the case is not used and the external electrode which is electrically connected to the stator electrode is formed on the stator, the conventional variable capacitor in which the terminals on the stator side are arranged in the case by a method such as insert molding is used. Since it does not need to be large in size and does not require a case or a terminal on the stator side, it is possible to reduce the number of parts, simplify the manufacturing process, and reduce the manufacturing cost.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. 1A and 1B are views showing a variable capacitor according to an embodiment of the present invention. FIG. 1A is a plan view, FIG. 1B is a front sectional view, and FIG. 1C is a bottom view. In addition, FIG.
It is an exploded perspective view showing an engaging structure of a stator and a shaft.

The variable capacitor according to this embodiment has a stator 2 having a stator electrode 1, a metallic rotor 3 disposed on the upper surface of the stator 2, and a rotor 3 having a stator 2.
Through a spring member (spring washer) 4 for press contacting with the stator 1, the rotor 3 and the spring member 4, and the elastic force of the spring member 4 presses the rotor 3 against the stator 1.
And a shaft 11 that holds the rotor 3 on the stator 1 so as to be slidably rotatable. The lower end surface of the shaft 11 has a lower surface (rear surface) of a substrate mounted after mounting.
Driver groove 14 so that adjustment can be performed from the side
Are formed.

The stator 2 is composed of a ceramic dielectric 6, and as shown in FIG. 2, a hole (shaft through hole) 12 through which the shaft 11 penetrates is formed in the central portion thereof. Further, inside the stator 2, one stator electrode 1 extending from the substantially central portion to one end portion is formed. An external electrode 7a is formed at the end of the stator 2 from which the stator electrode 1 is drawn out, and is in electrical communication with the stator electrode 1.

On the lower surface of the stator 2, the shaft 1
A rotor extraction electrode 5 that is electrically connected to the rotor 3 via the spring 1 and the spring member 4 is formed.
Is electrically connected to the external electrode 7b formed at the other end of the stator 2.

The external electrodes 7a and 7b can be formed by various known methods such as a method of coating and baking a conductive paste.

The stator 2 can be manufactured by a method of laminating and sintering an electrode layer and a ceramic dielectric layer (ceramic green sheet) according to a method of forming a monolithic ceramic capacitor. It can be manufactured by other methods.

The rotor 3 is made of metal such as brass. As shown in FIGS. 1 and 2, a hole (shaft through hole) 13 through which the shaft 11 penetrates is formed in the central portion. The hole 13 is configured to have a quadrangular cross section corresponding to the shape (quadratic prism shape) of the rotor penetrating portion 11a of the shaft 11 so as to rotate together with the shaft 11. Further, on the upper surface side of the rotor 3, a plus type groove (driver groove) 8 for rotating the rotor 3 from the outside with a tool such as a screwdriver is formed. On the other hand, rotor 3
Of the surface facing the stator 2 is approximately half (9 in FIG.
(B)) is projected, and this projected portion 9 substantially functions as a rotor electrode. The stator 2 of the rotor 3
An arcuate ridge 3a is formed on the peripheral portion of the retracted portion 10 (FIG. 1 (b)) of the surface facing the and so that the rotor 3 can rotate smoothly. Instead of the ridge 3a, it is possible to provide a protrusion at a predetermined position of the recessed portion 10.

The shaft 11 passes through the stator 2, the rotor 3 and the spring member 4, and its upper end 11c is crimped so as to engage with the spring member 4. Further, as described above, the rotor penetrating portion 11a of the shaft 11 is formed in a quadrangular prism shape corresponding to the shape of the shaft penetrating hole 13 of the rotor 3 so that the rotor 3 can be rotated together. The stator penetrating portion 11b of the shaft 11 is formed in a cylindrical shape so as not to rotate the stator together.

Further, as described above, the driver groove 14 for engaging a tool such as a driver to rotate the shaft is formed on the lower end surface of the shaft 11.

In the variable capacitor constructed as described above, the stator electrode 1 and the rotor 3 function as a fixed side electrode and a movable side electrode, respectively, and an adjustable capacitance is formed between them. This electrostatic capacitance is taken out to the outside by the external electrode 7a which is in conduction with the stator electrode 1 and the external electrode 7b which is in conduction with the rotor extraction electrode 5.

Further, in the variable capacitor of this embodiment constructed as described above, since the stator electrode 1 is formed inside (the ceramic dielectric 6 forming the stator 2), the total thickness of the stator 2 is large. While the thickness of the dielectric layer 6a between the stator electrode 1 and the rotor 3 (the protruding portion 9 thereof) can be reduced,
It is possible to form a large capacitance without reducing the strength of the stator 2.

Further, since the stator 2 is formed with the external electrode 7a which is electrically connected to the stator electrode 1 and the external electrode 7b which is electrically connected to the rotor extraction electrode 5, the stator side terminal and the rotor side are formed on the case by a method such as insert molding. It does not need to be upsized as in the conventional variable capacitors with terminals and the like, and also has a case, a stator side terminal,
Since the rotor side terminal is not required and the number of parts is reduced, the manufacturing process can be simplified and the manufacturing cost can be reduced.

FIG. 3 is a sectional view showing the structure of a variable capacitor according to another embodiment of the present invention.

In the variable capacitor of this embodiment,
As the stator 2, a pair of stator electrodes 1a, 1
A stator formed so that b is symmetrical is used. The stator electrode 1a is connected to the external electrode 7a on one end side of the stator 2, the stator electrode 1b is connected to the external electrode 7b on the other end side, and the stator electrode 1b is a dummy.

Since the configuration of the other parts is the same as that of the variable capacitor of the above-described embodiment shown in FIG. 1, the description of the related parts will be cited and the description thereof will be omitted.

In the variable capacitor of this embodiment,
Inside the stator 2, a pair of substantially symmetrical stator electrodes 1
Since a and 1b are formed and external electrodes 7a and 7b that are electrically connected to the stator electrodes 1a and 1b are formed at substantially symmetrical positions on both ends of the outside, the direction of the stator 2 in the assembly process is increased. And the manufacturing process can be simplified. Further, since the external electrodes 7a and 7b of the stator 2 are a pair (two) and are bilaterally symmetrical, the reliability of soldering to the substrate at the time of mounting can be improved. Further, in other respects, the same effects as those of the variable capacitor of the above embodiment can be obtained.

FIG. 4 is a sectional view showing a variable capacitor according to still another embodiment of the present invention. In the variable capacitor of this embodiment, the lower portion of the shaft 11 having the driver groove 14 and the like is housed in the recess 2a formed on the lower surface side of the stator 2, and the rotor extraction electrode 5 is provided inside the stator 2. The variable capacitor is formed (that is, serves as an internal electrode), and the entire lower surface of the variable capacitor is configured to be substantially flat.

Since the configuration of the other parts is the same as that of the variable capacitor of the above-described embodiment shown in FIG. 1, the description of the related parts will be cited and the description thereof will be omitted.

The recess 2a can be formed by, for example, the method described below. That is, in the case where the ceramic green sheets printed with the electrode patterns to be the stator electrodes are stacked and the stator is formed by firing this, the predetermined positions of the predetermined number of ceramic green sheets (the positions where the concave portions 2a should be formed) are formed. ) Is printed with a material that is burnt out during firing, for example, carbon paste is laminated, pressure-bonded and then fired to burn off the carbon paste, and the recessed portion 2a of the sintered body (stator) is to be formed at a position where it should be formed. Forming a portion in which a plurality of hollow layers and thin ceramic dielectric layers are alternately arranged inside, and crushing and polishing this portion by a method such as barrel polishing to form a recess 2a at a predetermined position. You can According to this method, the recess 2a can be easily formed at a predetermined position of the stator 2.

Since the lower surface of the variable capacitor of this embodiment is formed flat, it is necessary to perform adjustment from the lower surface (back surface) side of the substrate after mounting, like the variable capacitor of the above embodiment shown in FIG. Not only can it be used as a variable capacitor of the type that can be used, but it can also be used as a surface-mounted variable capacitor.

FIG. 5 is a sectional view showing a variable capacitor according to still another embodiment of the present invention, (a) is a front sectional view and (b) is a bottom view.

In the variable capacitor of this embodiment,
A step portion (recess) 2b is formed on the lower surface side of the stator 2, and the lower portion of the shaft 11 having the driver groove 14 and the like is housed in the step portion 2b so that the lower surface side is substantially flat. . Further, a metal terminal (rotor extraction electrode) 5a connected to the rotor 3 via the shaft 11 and the spring member 4 is provided, and no external electrode 7b (Fig. 1 and the like) is provided.

Since the configuration of the other parts is the same as that of the variable capacitor of the above-described embodiment shown in FIG. 1, the description of the related parts will be cited and the description thereof will be omitted.

Also in the variable capacitor of this embodiment,
It is possible to obtain substantially the same effect as the variable capacitor of the above embodiment shown in FIG.

6A and 6B are sectional views showing a variable capacitor according to still another embodiment of the present invention. FIG. 6A is a front sectional view and FIG. 6B is a bottom view.

In the variable capacitor of this embodiment,
A stator 2 in which a pair of internal electrodes 1a, 1b and external electrodes 7a, 7b are formed, and both longitudinal ends of the lower surface of the stator 2 are projected downward to form a groove 2c in the central longitudinal direction is used. There is. The lower surface of the shaft 11 and the metal terminal (rotor extraction electrode) 5a connected to the rotor 3 are arranged in the groove 2c of the stator 2 so that the lower surface is substantially flat.

Since the configuration of the other parts is the same as that of the variable capacitor of the above-described embodiment shown in FIG. 1, the description of the related parts will be cited and the description thereof will be omitted.

Also in the variable capacitor of this embodiment,
It is possible to obtain substantially the same effect as the variable capacitor of the above embodiment shown in FIG.

In each of the above embodiments, the case where the rotor made of metal is used as the rotor has been described. However, as the rotor, in addition to the rotor made of metal, at least part of an insulator such as alumina (for example, It is also possible to use a rotor formed by metallizing a part of the surface facing the stator) by a method such as metal plating, that is, a rotor formed by forming electrodes on a part of an insulator.

In each of the above embodiments, the case where the spring washer is used as the spring member has been described.
The spring member is not limited to this, and another type of spring member such as a coil spring can be used by appropriately changing the shape of the shaft.

The variable capacitor of the present invention is not limited to the above embodiment in other respects, and the specific shapes and arrangement positions of the stator and the stator electrode, the shape of the metallic rotor, and the like. Various applications and modifications can be made within the scope of the invention with respect to the constituent material, the metallizing method in the case of using the metallized rotor, the specific shape of the shaft, the constituent material, and the like.

[0046]

As described above, in the variable capacitor of the present invention, the stator electrode is formed inside and the external electrode that is electrically connected to the stator electrode is formed outside, and the variable capacitor is rotatable on the stator. With attached rotor,
A spring member that is arranged on the upper surface side of the rotor and presses the rotor to the stator, a rotor extraction electrode that is in conduction with the rotor (movable side electrode), a stator and the rotor, and the rotor rotates together. A shaft having a driver groove formed on its lower end face, which engages with the rotor in a form and engages with a spring member to hold the rotor so as to be slidably rotatable in a state of being pressed against the stator. It is possible to increase the thickness of the entire stator while decreasing the thickness of the dielectric layer between the stator electrode and the rotor (movable side electrode).
A large capacitance can be formed without reducing the strength of the stator.

Further, since the stator is formed with the external electrode which is electrically connected to the stator electrode, it is not necessary to increase the size as in the conventional variable capacitor in which the stator side terminal is arranged in the case by a method such as insert molding. Also, since it does not require a case or a terminal on the stator side,
It is possible to reduce the number of parts, simplify the manufacturing process, and reduce the manufacturing cost.

[Brief description of drawings]

1A and 1B are views showing a variable capacitor according to an embodiment of the present invention, in which FIG. 1A is a plan view, FIG.
(C) is a bottom view.

FIG. 2 is an exploded perspective view showing an engaging structure of a rotor, a stator, and a shaft that constitute a variable capacitor according to an embodiment of the present invention.

FIG. 3 is a sectional view showing a variable capacitor according to another embodiment of the present invention.

FIG. 4 is a sectional view showing a variable capacitor according to still another embodiment of the present invention.

5A and 5B are views showing a variable capacitor according to still another embodiment of the present invention, wherein FIG. 5A is a front sectional view and FIG. 5B is a bottom view.

6A and 6B are views showing a variable capacitor according to still another embodiment of the present invention, wherein FIG. 6A is a front sectional view and FIG. 6B is a bottom view.

FIG. 7 is a cross-sectional view showing a conventional variable capacitor.

[Explanation of symbols]

 1 Stator Electrode 2 Stator 2a Recess 2b Step 2c Groove 3 Rotor 4 Spring Member 5 Rotor Extraction Electrode 6 Ceramic Dielectric 7, 7a, 7b External Electrode 8 Rotor Driver Groove 11 Shaft 14 Shaft Driver Groove

Claims (1)

[Claims] 1. A stator made of a ceramic dielectric material, wherein a stator electrode that functions as a fixed-side electrode is formed inside, and an external electrode that is electrically connected to the stator electrode is formed outside, and a stator that rotates on the stator. A rotor that is movably attached and that is made of metal or has an electrode formed on at least a part of an insulator and that functions as a movable electrode; A spring member to be pressed into contact with the rotor, a rotor lead electrode that is in conduction with the rotor (movable side electrode), and at least penetrates the stator and the rotor and engages with the rotor in such a manner that the rotor rotates together. , A lower side that engages with the spring member and elastically holds the rotor so that the rotor is slidably rotatable in a state of being pressed against the stator. Variable capacitor characterized by comprising a shaft driver groove is formed on the surface.