JP2001126957A - Variable capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a variable capacitor which can be assembled very easily and in which the closely contacted state of a metallic rotor with a dielectric substrate is stabilized, and the rotation of the rotor becomes highly stabilized. SOLUTION: A variable capacitor is composed of a dielectric substrate 1 having a stator electrode 11, a metallic rotor 2 having rotor electrodes 21 which are in close-contact with the substrate 1 and a driver groove 23 for adjustment formed on its upper surface, a resin case 3 which houses the substrate 1 and rotor 2 and is provided with stator terminals 6 connected to stator electrodes 11. The capacitor is also composed of rotor terminals 5, which extend to the top opening 41 of a metallic cover 4 covering the upper surface of the resin case 3 and the outer peripheral surface of the case 3 and the metallic cover 4. The capacitor also has recessed sections 8 which are arranged intermittently in the circumferential direction and protruded toward the rotor 2 around the top opening 41 of the cover 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable capacitor, in which a dielectric substrate and a metal rotor are arranged in a resin case, and a capacitance value is obtained by rotating the metal rotor on the dielectric substrate. The present invention relates to a closed type variable capacitor that can be changed.

[0002]

2. Description of the Related Art Conventionally, variable capacitors are roughly classified into open type and closed type variable capacitors. For example, an open type variable capacitor has a structure in which a dielectric rotor is disposed on a resin stator substrate having a stator electrode, and an adjustment pin that enables the dielectric rotor to rotate is disposed. In such a variable capacitor, a stator substrate having a stator electrode is a composite member of metal and resin. Therefore, even if the surface of the stator substrate is polished, the flatness of the surface is reduced, and the surface is significantly deformed due to a difference in coefficient of thermal expansion. In particular, there has been a fatal problem that when reflow soldering is performed for mounting on a printed wiring board, the deformation is severe, and a characteristic change occurs after mounting.

[0003] Further, a closed type variable capacitor has a dielectric substrate and a metal rotor disposed inside a resin case, and further, a spring member is disposed on the metal rotor, and an upper opening of the resin case is covered with a lid. I was The rotor terminal connected to the metal rotor is formed integrally with the spring member,
A stator electrode is extended outside the resin case, a stator electrode is attached to the lower surface side of the dielectric substrate, and a stator terminal connected to the stator electrode is integrally formed in the resin case.

[0004] In such a closed type variable capacitor, the metal rotor and the dielectric substrate are brought into close contact with each other by the elastic force of the spring member. Therefore, there is a problem that the characteristics are changed unless the resin case is stably fixed to the lid for fixing the spring member.

Japanese Patent Laid-Open No. Hei 10-189392 discloses a structure for bringing a metal rotor into close contact with a dielectric substrate. In Japanese Patent Application Laid-Open No. Hei 10-189392, a spring member is eliminated, the lid is made of metal, and the entire upper surface of the metal cover is tiled. A curved structure is disclosed. And, by this curved structure, a spring property is generated, and the close contact between the metal rotor and the dielectric substrate is improved by using a spring washer.

In Japanese Patent Application Laid-Open No. 10-189392,
An adjustment opening for rotating the metal rotor is formed on the upper surface of the metal cover, and a slope is formed so that the periphery of the opening faces downward to improve the spring property.

Further, in Japanese Patent Application Laid-Open No. 63-115318, a plurality of cutouts are formed around the opening on the upper surface of the metal cover, and a continuous portion between the cutout and the upper surface of the metal cover is bent to form a cutout. The notch has used the metal rotor as an elastic member for pressing the dielectric substrate.

[0008]

The above-mentioned Japanese Patent Application Laid-Open No. Hei 10-1
In the variable capacitor shown in 89392, the shape of the upper surface of the metal cover is a tiled curved shape, thereby generating a spring property and ensuring the adhesion between the metal rotor and the dielectric substrate. . However, it is necessary to reduce the radius of the curved structure of the metal cover in order to have sufficient spring properties.

Further, a spring washer is used between the metal cover itself and the metal rotor while generating spring properties.
That is, by using this spring washer, the number of components is increased, and it is difficult to reduce the height.

Further, if a washer is formed by bending a part of the metal cover, unevenness occurs in the pressure applied to the metal rotor along the bending direction. This allows
The rotation torque becomes uneven.

Further, when a tile-shaped curved shape is formed on the upper surface of the metal cover and a slope extending downward around the adjustment hole is formed, the contact between the metal rotor and the rear surface of the metal cover is poor, so that the contact resistance increases, Since the pressure for suppressing the pressure becomes uneven, stable characteristics cannot be obtained.

In Japanese Patent Application Laid-Open No. 63-115318,
When the elastic member is formed by the notch, the bending direction of the notch and the rotation direction of the metal rotor may be the forward direction, but the contact resistance in the reverse direction increases, and the rotation torque becomes uneven. Would.

Further, the bending state of the continuous portion between the upper surface of the metal cover and the notch changes with time, and as a result, the close contact state between the metal rotor and the dielectric substrate fluctuates. As a result, the characteristics fluctuate.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has as its object to assemble it very easily, stably maintain the close contact between the metal rotor and the dielectric substrate, and furthermore, An object of the present invention is to provide a variable capacitor in which the rotation of the rotor is very stable.

[0015]

According to the present invention, there is provided a dielectric substrate made of a dielectric ceramic having a stator electrode on a lower surface, and a dielectric substrate disposed on an upper surface of the dielectric substrate and closely contacted with the dielectric substrate on a lower surface. A metal rotor having a rotor electrode to be adjusted and having a driver groove for adjustment on the upper surface side, fixedly housing the dielectric substrate, and rotatably housing the metal rotor, and A resin case having a stator terminal connected to a stator electrode, a rotor terminal that covers the resin case, has an upper surface opening that exposes a driver groove of the metal rotor on the upper surface, and extends to the outer periphery of the resin case; and A metal cover having fixed legs, wherein the metal cover has an elastic contact with the metal rotor around the upper surface opening of the metal cover. A variable capacitor intermittently forming a recess in the circumferential direction.

[0016]

The variable capacitor according to the present invention does not use a spring washer. That is, the spring property for improving the contact between the metal rotor and the dielectric substrate is achieved by the shape of the metal cover.

Further, since only the dielectric substrate and the metal rotor are accommodated in the resin case in which the stator terminals are integrated and the metal cover is covered, the assembling becomes very simple.

In order to maintain sufficient contact between the metal rotor and the dielectric substrate, around the top opening of the metal cover,
A plurality of depressions are formed intermittently in the circumferential direction. The depression is formed from the upper surface to the lower surface of the metal cover by extrusion of a metal material or by a pressing jig having a convex section. That is, the continuous portion between the depression and the upper surface of the metal cover is
This is at least the circumferential end of the recess.

[0019] When the tip of the recess contacts the upper surface of the metal rotor, a spring property between the metal rotor and the dielectric substrate is obtained. At the same time, even if the metal rotor is rotated in one direction or the other direction in order to obtain a predetermined capacity component, stable rotation torque can be obtained because only the tip end is in contact.

In addition, since at least both ends of the recess in the circumferential direction are integrated with the upper surface of the metal cover, the rigidity of the recess increases. Therefore, there is little variation in the adhesion between the metal rotor and the dielectric substrate (spring property due to the depressions), and stable characteristics can be derived. Further, the top surface of the metal cover is substantially planar, and a variable capacitor with a reduced height can be provided.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a variable capacitor according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is an external perspective view of a variable capacitor according to the present invention, FIG. 2 is a sectional structural view, and FIG. 3 is a partial sectional view of a concave portion of a metal cover.

The variable capacitor 10 of the present invention mainly comprises a dielectric substrate 1, a metal rotor 2, a resin case 3, and a metal cover 4. The rotor terminal 5 and the engagement fixing leg 7 are integrated with the metal cover 4, and the stator terminal 6 is integrated with the resin case 3.

The dielectric substrate 1 is formed by powder molding and firing of a dielectric ceramic material, and the dielectric substrate is processed to a desired thickness by double-side polishing, and the lower surface of the base is made of an electrode 11 made of silver or the like. Is formed. Since the dielectric substrate 1 is fixedly disposed in the resin case 3, it is formed, for example, in a substantially rectangular shape.

The metal rotor 2 has a disk shape as a whole, and has a rotor electrode 21 formed on the lower surface thereof. When the metal rotor 2 is arranged on the dielectric substrate 1, the rotor electrode 21 faces the stator electrode 11 via the dielectric substrate 1.

On the lower surface side of the metal rotor 2, a projection 22 is formed with the same height as the height of the rotor electrode 21.

Further, a driver groove 23 into which a tool such as a driver for rotating the metal rotor 2 is inserted and a positioning recess 24 indicating the direction of the rotor electrode 21 are formed on the upper surface side of the metal rotor 2. Such a metal rotor 2 is made of a metal such as brass, for example, and is processed into a predetermined shape by casting, pressing, etching, or the like.

The resin case 3 is made of a thermoplastic resin having high heat resistance such as polyphenylene sulfide or liquid crystal polymer, or a thermosetting resin such as epoxy resin or unsaturated polyester. Are integrally formed.

The inside of the resin case 3 includes the dielectric substrate 1
Are fixedly accommodated and the metal rotor 2 is rotatably accommodated.

At least one pair of side surfaces of the resin case 3 is formed with a locking concave portion 31 that engages with the engagement fixing leg 7.

The stator terminal 6 is formed so as to be folded at the bottom of the concave portion of the resin case 3 and to be exposed at the bottom of the resin case 3. That is, one end of the stator terminal 6 is in contact with the stator electrode 11 formed on the lower surface of the dielectric substrate 1.

The metal cover 4 is made of a metal as a whole, and has an adjustment opening 41 for exposing the driver groove 23 of the metal rotor 2 on the upper surface of the cover 4.

At the end of the metal cover 4, an engagement fixing leg 7 and a rotor terminal 5 extend along the side surface of the resin case 3.

The engagement fixing legs 7 extending along the side surfaces of the resin case 3 are respectively formed on at least one pair of side surfaces of the resin case 3.

An engagement portion (tip portion) 71 which is turned inward is formed at the tip of the engagement fixing leg 7, and the engagement portion 71 of the engagement fixing leg 7 is made of resin. Case 3
Side engaging recess 31. As a result, the resin case 3 and the metal cover 4 are firmly fixed. In the present embodiment, in order to suppress rattling between the resin case 3 and the metal cover 4, an inclined portion 72 is formed by bending the distal end portion of the engagement fixing leg portion 7 inward. Thus, the resin case 3 is always clamped by the locking portions 71 of at least one pair of the engagement fixing legs 7 of the metal cover 4. This prevents rattling of the metal cover 4 in the planar direction. In addition, the locking concave portion 31 of the locking portion 71
By this engagement, rattling in the upper surface direction of the metal cover 4 is prevented.

The rotor terminals 5 extend from the upper surface of the metal cover 4 to the side surfaces of the resin case 3 along the bottom surface. That is, the rotor terminals 5 are provided on the bottom surface of the resin case 3.
And the stator terminal 6 are located respectively.

Further, a pair of end sides different from the end sides on which the engagement fixing leg portions 7 and the rotor terminals 5 of the metal cover 4 extend,
The side reinforcing plate 42 extends downward. The pair of side reinforcing plates 42 prevent rattling with the resin case 3 and increase the rigidity of the metal cover 4 itself.

Here, according to the present invention, the metal cover 4 is provided around the adjustment opening 41 formed on the substantially flat upper surface.
A plurality, for example, four depressions 8 are formed intermittently in the circumferential direction. In FIG. 1, the metal cover 4 is arranged at diagonal portions of the four corners, but in the sectional structural view of FIG. 2, the cross section is slightly different so that the structure can be clearly understood.

The recess 8 protrudes downward so as to contact the upper surface of the metal rotor 2 along the circumferential direction around the adjustment opening 41, that is, the rotation direction of the metal rotor 2. Then, the front end portion 81 at the center thereof contacts the metal rotor 2, and the whole has a funnel shape inclined. That is, as shown in the partial cross-sectional view of FIG. 3, the concave portion 8 has inclined surfaces 82 and 83 that are inclined in the circumferential direction from the distal end portion 81 to the upper surface of the metal cover 4. Therefore, both ends in the circumferential direction of the recess 8 are formed integrally with the upper surface of the metal cover 4.

The depression 8 is formed, for example, by pressing from the upper surface side of the metal cover 4 using a pressing jig having a convex cross section, or by extruding the metal cover. The tip 81 of the recess 8 is formed at a circumferential position avoiding at least the driver groove 23 and the positioning recess 24 of the metal rotor 2, so that the metal rotor 2 can be securely rotated no matter how the metal rotor 2 is rotated. Is configured so as to elastically contact the upper surface at a plurality of locations.

The depression 8 is formed, for example, by the metal cover 4.
Are formed around the opening 41, but a plurality of grooves are formed on each of two circumferences so as to avoid the driver groove 23 and the positioning recess 24 and in consideration of the rigidity of the metal cover 4. It does not matter.

Next, a method of assembling a variable capacitor using the dielectric substrate 1, the metal rotor 2, the resin case 3, and the metal cover 4 will be described.

That is, the dielectric substrate 1 and the metal rotor 2 are sequentially inserted and arranged in the resin case 3 in which the stator terminals 6 are integrated. At this time, the dielectric substrate 1 is fixedly accommodated in the resin case 3, and the metal rotor 2 is rotatably accommodated on the dielectric substrate 1. Note that an insulating lubricant such as silicon oil is applied to the upper surface side of the dielectric substrate 1, and the metal rotor 2 is disposed thereon.

Next, the metal cover 4 is arranged on the resin case 3 so as to cover the upper opening of the resin case 3. Then, the metal cover 4 is pressed in the lower direction, and the locking portion 71 of the engagement fixing leg 7 is pushed in until it engages with the locking recess 31 of the resin case 3.

Thereafter, the distal end 71 of the engaging and fixing leg 7 is pressed in the lateral direction of the resin case 3, and the distal end 71 of the pair of engaging and fixing leg 7 sandwiches the resin case 3 from both lateral directions. .

At this time, the engagement between the metal cover 4 and the resin case 3 becomes stronger due to the reverse tapered portion 32 provided in the locking recess 31 of the case 3.

When the metal cover 4 is fixed at a predetermined position, the plurality of depressions 8 formed on the upper surface of the metal cover 4 elastically press the metal rotor 2 downward. Thereby, the rotor electrode 2 of the metal rotor 2
1 comes into close contact with the upper surface of the dielectric substrate 1.

In the variable capacitor assembled as described above, the rotor electrode 21 of the metal rotor 2 and the dielectric substrate 1
A predetermined capacitance is generated depending on the area of the lower surface of the substrate facing the stator electrode 11, the thickness of the dielectric substrate 1, and the dielectric constant. Then, by rotating the metal rotor 2 by a predetermined amount, the facing area between the rotor electrode 21 and the stator electrode 11 changes, so that the capacitance component can be variably controlled.

Then, the metal rotor 2 is electrically connected to the rotor terminal 5 via the recess 8 of the metal cover 4 and is connected to the rotor terminal 5. Also, the stator electrode 1 of the dielectric substrate 1
1 is directly connected to the stator terminal 6. Therefore, the above-mentioned capacitance component is composed of the rotor terminal 5 and the stator terminal 6.
Will be derived from

In the present invention, the top surface of the metal cover 4 is substantially flat (except for the recessed portion 8).
As shown in Japanese Patent No. 189392, the shape of the metal cover 4 is not made to be a partial cylindrical peripheral surface, so that the configuration of the metal cover 4 is simplified and its processing is facilitated.

At the same time, the height of the variable capacitor itself is reduced.

Further, since the metal rotor 2 is in direct pressure contact with the tip of the recess 8 of the metal cover 4, an elastic force is effectively exerted. That is, JP-A-10-18
As shown in No. 9392, since no washer is used, there is no unevenness in rotational torque and the number of parts does not increase. At the same time, the height of the variable capacitor itself can be reduced.

In particular, in this embodiment, the recess 8 is formed intermittently in the circumferential direction around the adjustment opening 41 on the upper surface of the metal cover 4. Moreover, it protrudes inward. The plurality of depressions 8 are arranged in the circumferential direction (corresponding to the rotation direction of the metal rotor 2). Moreover, both circumferential ends of the recess 8 are integrated with the upper surface of the metal cover 4 via the inclined surfaces 82 and 83.

That is, regardless of which direction (clockwise or counterclockwise) the metal rotor 2 is rotated in the circumferential direction, the inclined surface 8
2, 83 do not hinder the rotation operation, and furthermore, both ends in the circumferential direction of the recess 8 are integrated with the upper surface of the metal cover 4 to prevent damage and deformation of the recess 8. Can be suppressed. Thus, the metal rotor 2 can be pressed against the dielectric substrate 1 with a stable elastic force. In Japanese Patent Application Laid-Open No. 63-115318, a member that gives elasticity to a metal rotor is a leaf spring.
A part of the upper surface of the metal cover was cut into a U-shape and bent at a continuous portion with the metal cover. Therefore, the turning torque varies between the same rotation direction of the metal rotor and the opposite direction with respect to the inclined surface of the leaf spring. Also, since only one end of the leaf spring is fixed to the metal cover 4, its rigidity is low and it is easily broken.

As described above, since this embodiment does not use a washer, the number of parts is reduced, and the structure and assembly are simplified. In addition, by forming a plurality of, for example, four recesses 8 in the adjustment opening 41 of the metal cover 4, the metal rotor 2 and the dielectric substrate 1 can be stably contacted by this elastic force. it can.

Further, since the upper surface of the metal cover 4 can have a planar shape, the height can be reduced. The recess 8 has a tip portion 81 and at least inclined surfaces 82 and 83 in the circumferential direction with respect to the tip portion 81. For this reason, even if the metal rotor 2 rotates clockwise and counterclockwise,
In either case, contact is made with the inclined surfaces 82 and 83, so that stable rotation is possible. Accordingly, it is easy to cope with the automatic adjustment.

In the above-described example, the depression 8 is formed in a substantially convex shape having two inclined surfaces 82 and 83 along the circumferential direction. However, as shown in FIG. 84
However, it may be formed in an inverted bowl shape so as to have an inclined surface 85 around the periphery.

[0058]

As described above, the structure and its assembly are very simple, the close contact between the metal rotor and the dielectric substrate is stable, and the rotation of the metal rotor is very stable, and the height is reduced. Is a variable capacitor.

[Brief description of the drawings]

FIG. 1 is an external perspective view of a variable capacitor according to the present invention.

FIG. 2 is a sectional structural view of a variable capacitor according to the present invention.

FIG. 3 is a partial side view of a depression according to the present invention.

FIG. 4 is a sectional structural view of another variable capacitor of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Dielectric board 11 ... Stator board 2 ... Metal rotor 21 ... Rotor electrode 22 ... Convex part 23 ... Driver groove 24 ... Positioning recess 3 ... Resin case 31 ... Engagement recess 4 Metal cover 41 Adjustment opening 5 Rotor terminal 6 Stator terminal 7 Engagement fixed leg 71 Tip end 72 Slope Part 8 ... recessed part 81, 84 ... tip part 82, 83, 85 ... inclined surface

Claims (1)

[Claims] 1. A dielectric substrate comprising a dielectric ceramic having a stator electrode on a lower surface, and a rotor electrode disposed on an upper surface of the dielectric substrate and closely contacting the dielectric substrate on a lower surface, and A metal rotor having an adjustment driver groove on an upper surface side; and a stator terminal fixedly receiving the dielectric substrate, rotatably receiving the metal rotor, and connecting to a stator electrode of the dielectric substrate. And a metal cover that covers the resin case, has a top surface opening that exposes a driver groove of the metal rotor on the top surface, and has a rotor terminal and fixed leg portions that extend around the resin case. In a variable capacitor comprising: a concave portion elastically contacting the metal rotor around the upper surface opening of the metal cover; Variable capacitor, characterized in that the intermittently formed along the.