JPH0318726B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a trimmer capacitor used as an electronic circuit component.

[Prior Art] As a conventional trimmer capacitor, a cylindrical type as shown in FIG. 3 is a cylindrical fixed electrode fitted on the outer periphery of the insulating cylinder 1; 3 is a cylindrical terminal electrode disposed on the other end side of the insulating cylinder 1 and fixed to the insulating cylinder 1 with an adhesive 4; 5 is an insulating cylinder an electrode part 5a that is inserted into the insulating cylinder and faces the fixed electrode through the insulating cylinder; a threaded part 5b having a male screw part carved on the outer periphery; and a head part 5c having a groove 5c1 into which a bit of a driver is inserted. The threaded portion 5b of the movable electrode 5 is screwed into the female threaded portion 3b provided on the inner periphery of the terminal electrode 3. In order to set the required operating torque for rotating the movable electrode to a predetermined value, the female screw 3 of the terminal electrode 3 is
A plurality of slots 3a extending in the axial direction are provided on the peripheral wall of the end portion 3b1 of the portion where b is provided, and the peripheral wall divided by the slots is narrowed inward in the radial direction, and the screw of the movable electrode 5 The part 5b is the sliding part 3a.
The terminal electrode 3 is screwed into the female threaded portion 3b of the terminal electrode 3 against the elasticity of the divided peripheral wall portion.

[Problems to be Solved by the Invention] As described above, in the conventional capacitor of this type, it is necessary to provide the terminal electrode 3 with a female screw portion, and in addition, in order to obtain the required operating torque of the movable electrode, the terminal electrode Since the slot 3a was provided in the slit 3a, machining was troublesome. In addition, it is necessary to secure a slot at the end of the terminal electrode in the axial direction.
There was a problem in that the axial dimension of the terminal electrode became long, which became an obstacle to downsizing the trimmer capacitor.

Furthermore, in the conventional trimmer capacitor, after the terminal electrode 3 was positioned concentrically with respect to the insulating cylinder 1, the terminal electrode was fixed to the insulating cylinder 1 with adhesive 4, making it difficult to automate assembly.
As a result, manufacturing efficiency could not be improved and costs increased.

In addition, in order to obtain linearity of capacitance in this type of trimmer capacitor, it is necessary to maintain a small distance between the electrode part of the movable electrode and the insulating cylinder so that the electrode part does not come into contact with the inner surface of the insulating cylinder. However, with the conventional structure, it is extremely difficult to form a minute gap between the electrode part of the movable electrode and the insulating cylinder, and due to assembly variations, the electrode part of the movable electrode may come into contact with the insulating cylinder. Capacitance linearity was often not achieved.

An object of the present invention is to be able to obtain a predetermined operating torque without providing a female threaded portion or slot on a terminal electrode, and to easily assemble the terminal electrode without positioning or gluing. Our goal is to provide trimmer capacitors that can.

[Means for Solving the Problems] The present invention provides an insulating cylinder 10 made of a dielectric material,
A cylindrical fixed electrode 11 fitted on the outer periphery of one end of the insulating cylinder 10, a terminal electrode 12 arranged on the other end of the insulating cylinder 10 and fixed to the insulating cylinder, and a terminal electrode 12 inside the insulating cylinder 10. The electrode part 14a that is inserted and faces the fixed electrode 11 through the insulating cylinder is integrated with a threaded part 14b having a male thread carved on the outer periphery, and the threaded part is electrically connected to the terminal electrode. This is an improved trimmer capacitor equipped with a columnar movable electrode 14 screwed into a female threaded portion of the trimmer capacitor.

In the first invention of the present application, as seen in FIG. 1 showing an embodiment thereof, the terminal electrode 12 is formed in the shape of a cylindrical body having an inner flange 12a facing the end surface on the other end side of the insulating cylinder 10. ing. A coiled member 13 is provided which is wound with an inner diameter and pitch that allows the threaded portion of the movable electrode 14 to be screwed into the coiled member 13, and the coiled member is adjacent to the inner flange 12a on the inner periphery of the terminal electrode 12. A female screw portion is formed by the coiled member that is fitted in position. The insulating cylinder 10 is press-fitted inside the terminal electrode 12 and fixed to the terminal electrode. The coiled member 13 is formed to have a polygonal contour inscribed in the terminal electrode 12, and the threaded portion 14b of the movable electrode is screwed into the coiled member.

Further, in the second invention of the present application, in addition to having the above configuration, the outer diameter of the electrode part 14a of the movable electrode is set smaller than the inner diameter of the insulating cylinder 10, and an insulating cylinder is provided between the electrode part and the threaded part. An enlarged diameter portion 14d that contacts the inner circumference of the movable electrode 10 is provided, and the electrode portion 14a of the movable electrode is positioned concentrically with respect to the insulating cylinder 10 by contact between the enlarged diameter portion 14d of the movable electrode and the insulating cylinder 10. .

[Function] With the above structure, the movable electrode 14 is supported by being screwed into the coiled member 13 having a polygonal outline. Further, the movable electrode contacts each side of the coiled member 13 from the inside and is electrically connected to the coiled member. Further, each vertex of the coiled member 13 contacts a terminal electrode, and the coiled member is electrically connected to the terminal electrode 12.

When the movable electrode is screwed onto the coiled member 13, a force acts to expand the inner dimension of the coiled member, but in the above configuration, the terminal electrode 12 contacts each vertex on the outer circumferential side of the coiled member 13. Since the coiled member is restrained by the movable electrode, there is no risk that the shape of the coiled member will be distorted and its inner dimension will be enlarged due to the force acting when the movable electrode is screwed together.

When the movable electrode 14 is rotated, the electrode portion 14a
is displaced in the axial direction, the opposing area between the electrode portion and the fixed electrode 11 changes, and the capacitance changes.

In this case, by appropriately setting the internal dimensions of the coiled member, the movable electrode can be easily provided with a predetermined required operating torque.

With the above configuration, there is no need to provide a threaded portion on the terminal electrode, and there is no need to provide a slot, making it possible to simplify the manufacture of the terminal electrode.

In addition, with the above configuration, there is no need to provide a part to form a slot in the terminal electrode, so
The axial dimension of the terminal electrode can be reduced, and the trimmer capacitor can be made smaller.

Furthermore, if the insulating cylinder is press-fitted into the terminal electrode as described above, there is no need for the troublesome work of positioning the insulating cylinder and the terminal electrode concentrically and gluing them together during assembly. , assembly can be easily automated.

It is also possible to form the coiled member to have a circular outline and make it contact the inner periphery of the terminal electrode, but in this case, the coiled member and the terminal electrode may Since it is not clear whether they are in electrical contact and it is difficult to clearly determine the contact point between the two, it is not possible to stably establish an electrical connection between the coiled member and the terminal electrode.

On the other hand, when the outline of the coiled member is made into a polygonal shape inscribed in the terminal electrode as in the present invention, each vertex of the outer circumferential portion of the coiled member reliably contacts the terminal electrode 12, and the coiled member The electrical contact point between the member and the terminal electrode is clearly determined. Moreover, since the force generated when the movable electrode is screwed onto the coiled member is concentrated at the contact portion between each vertex of the coiled member and the terminal electrode, each vertex of the coiled member strongly contacts the terminal electrode. Therefore, the electrical connection between the coiled member and the terminal electrode can be stably established.

Similarly, when the coiled member is formed into a circular shape, the electrical connection point between the threaded part of the movable electrode and the coiled member is not clearly defined, making it difficult to establish a stable electrical connection between the two. However, if the coiled member is formed into a polygonal shape as in the present invention, the threaded portion of the movable electrode will surely contact each side of the coiled member from the inside. In addition, the coiled member is restrained by the terminal electrode and its shape is maintained, and the shape of the coiled member does not collapse when the movable electrode is screwed together, so the electrical connection between the movable electrode and the coiled member is Connection can be made reliably.

Therefore, there is a synergistic effect between being able to make a stable electrical connection between the coiled member and the terminal electrode, and being able to make a stable electrical connection between the movable electrode and the coiled member. As a result, the electrical connection between the movable electrode and the terminal electrode can be ensured, and variations in the electrical characteristics of the product can be reduced and quality can be stabilized.

Furthermore, if the coiled member is circular, it is difficult to make uniform the mechanical contact between each part of the coiled member and the terminal electrode, so it is easier to keep the required operating torque of the movable electrode within a predetermined range. However, if the coiled member is formed into a polygonal shape, the contact points between the coiled member and the movable electrode are clearly defined, and the shape of the coiled member does not collapse, so the contact pressure at each contact point is reduced. By managing the internal dimensions of the coiled member so that the size of the movable electrode is appropriately controlled, the required operating torque of the movable electrode can be easily kept within a predetermined range.

In particular, according to the second invention, the enlarged diameter portion formed between the electrode portion and the screw portion of the movable electrode contacts the inner circumference of the insulating cylinder to position the electrode portion concentrically with respect to the insulating cylinder. Therefore, it is possible to maintain a small distance between the electrode part and the insulating cylinder so that the electrode part does not come into contact with the insulating cylinder, and it is possible to easily obtain linearity of capacitance.

[Examples] Examples of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows an embodiment of the present invention.
In the figure, 10 is an insulating cylinder made of a dielectric material such as ceramic. A cylindrical fixed electrode 11 having a required axial dimension is fitted onto the outer periphery of one end of the insulating cylinder 10 . The fixed electrode 11 has an inner flange 11a at one end and a flange 1 at the other end.
1b, and is attached to the insulating cylinder 10 with the inner flange 11a in contact with the end surface of one end of the insulating cylinder 10. If the fixed electrode is formed into this shape,
The fixed electrode can be positioned and attached to a predetermined position by simply pressing the insulating cylinder 10 into the inner periphery of the fixed electrode 11 and bringing its end surface into contact with the inner flange 11a of the fixed electrode. The work becomes easier and the automation of the installation work becomes easier.

Reference numeral 12 denotes a terminal electrode formed in a cylindrical shape that tightly fits on the outer periphery of the other end of the insulating cylinder 10. In this embodiment, like the fixed electrode 11, this terminal electrode has an inner flange portion 12a and a flange portion 12b. It is formed in a shape having the following. Inside this terminal electrode 12,
A coiled member 13 formed by bending a conductive wire is fitted, and this coiled member constitutes a female threaded portion into which a threaded portion of a movable electrode to be described later is screwed. This coiled member 13 is wound at least one turn or more, and its outline shape is formed into a polygon (quadrilateral or larger polygon) inscribed in the cylindrical portion of the terminal electrode 12, and its internal dimension and pitch P will be described later. The size is set such that the screw portion of the movable electrode can be screwed into the screw portion with a predetermined tightness. In this embodiment, as shown in FIG.
3 is formed to have a square outline shape. The coiled member 13 is inserted into the terminal electrode 12 to a position where it contacts the flange 12a, and the vertices of its four corners contact the inner circumference of the terminal electrode 12 and are electrically connected to the terminal electrode. ing.

14 is a substantially cylindrical movable electrode inserted inside the insulating cylinder 10;
a cylindrical electrode part 14a having an outer diameter set smaller than the inner diameter of an insulating cylinder 10 and facing the fixed electrode 11 via the insulating cylinder 10 so as to face the inner periphery of the insulating cylinder 10 with a minute distance g; It consists of a threaded part 14b with a male thread carved on the outer periphery and a head 14c connected to the threaded part 14b, and the head 14c has a groove 14c1 into which a bit of an adjustment tool such as a screwdriver is inserted. It is provided. Further, the electrode portion 14 of the movable electrode 14
An enlarged diameter portion 14d having an outer diameter that slidably contacts the inner periphery of the insulating cylinder 10 is formed at the boundary between the threaded portion 14b and the enlarged diameter portion 14b.
When d comes into contact with the inner circumference of the insulating cylinder 10,
The electrode portion 14a is automatically positioned concentrically with respect to the insulating cylinder 10. With the enlarged diameter portion 14d in contact with the inner periphery of the insulating cylinder 10, a predetermined minute gap 〓g is formed between the inner periphery of the insulating cylinder 10 and the outer periphery of the electrode portion 14a. is arranged so that it does not come into contact with the inner periphery of the insulating cylinder 10.

The movable electrode 14 is inserted into the insulating cylinder 10 from one end side of the insulating cylinder 10, and is inserted into the insulating cylinder 10 at its threaded portion 14b.
is screwed onto the coiled member 13. In this case, as shown in FIG. 3, the coiled member 13 comes into contact with the flank f of the threaded portion of the movable electrode 14, and the movable electrode 14 is screwed in the axial direction of the insulating cylinder 10 as it rotates. To move forward or backward.

In this case, the operating torque required to rotate the movable electrode can be arbitrarily set simply by appropriately setting the internal dimensions of the coiled member 13. Therefore, it is not necessary to provide a slot in the terminal electrode as in the conventional case, and the structure of the terminal electrode can be simplified and its manufacture can be facilitated. Further, the coiled member 13 can be attached by simply inserting it into the terminal electrode 12 to a position where it abuts the inner flange 12a. Furthermore, when connecting the terminal electrode and the insulating cylinder 10, it is sufficient to perform a simple operation of press-fitting the insulating cylinder 10 into the inner circumference of the terminal electrode 12. In this case, the depth of the press-fitting is such that the end of the insulating cylinder 10 The coiled member 13 is automatically regulated by coming into contact with the shaped member 13, and the coiled member 13 can be fixed at the same time by press-fitting the insulating cylinder 10 into the inner periphery of the terminal electrode 12, so the assembly work can be automated. It can be easily done.

Since the movable electrode 14 can be assembled by simply inserting it into an insulating cylinder and screwing its threaded portion onto the coiled member 13, the assembly work can be automated, and the structure of the present invention can ultimately For example, the entire assembly process can be automated. Furthermore, the movable electrode is automatically positioned concentrically with respect to the insulating cylinder 10 by screwing the threaded part 14b with the coiled member and by contacting the enlarged diameter part 14d with the inner periphery of the insulating cylinder 10. There is no need to perform center alignment between the movable electrode and the insulating cylinder, and a trimmer capacitor without center runout of the movable electrode can be easily obtained. In addition, the movable electrode 14 is always securely connected to the insulating cylinder 10.
As a result, a gap is reliably maintained between the electrode part 14a and the inner circumference of the insulating cylinder 10 to prevent the electrode part from coming into contact with the peripheral wall part of the insulating cylinder 10. Therefore, in addition to being able to prevent the center runout of the movable electrode, the linearity of the capacitance can be guaranteed, and the quality of the trimmer capacitor can be improved.

In the embodiments described above, the same member can be used for the terminal electrode 12 and the fixed electrode 11, and in this way, the types of parts can be reduced and the manufacturing process can be easily managed.

For example, as shown in FIG. 1, the trimmer capacitor described above is inserted into a mounting hole 15a provided on a printed circuit board 15, and the fixed electrode section 11 is connected to the electrode section provided on the printed circuit board by soldering. Ru. In this case, the flange portion 11b of the fixed electrode 11 comes into contact with the substrate 15 and the trimmer capacitor is automatically positioned, making it easy to automate the mounting of components onto the substrate. Note that the above trimmer capacitor should be attached to the board etc. using the terminal electrode 1.
Of course, this can also be done on both sides.

In the above embodiment, the outline shape of the coiled member 13 is square, but the coiled member may have a polygonal shape inscribed in the terminal electrode, and may have a polygonal shape of pentagon or more, for example, as shown in FIG. Alternatively, a coiled member 13 having a regular hexagonal outline may be used.

When the contour shape of the coiled member is polygonal in this way, each vertex of the outer circumference of the coiled member will surely contact the terminal electrode, and the contact point between the coiled member and the terminal electrode will be clear, so the coil Electrical connection between the shaped member and the terminal electrode can be ensured.

In order to obtain linearity of capacitance, as in the above embodiment, the movable electrode 14 is provided with an enlarged diameter portion 14d to create a minute gap between the electrode portion 14a and the inner circumference of the insulating cylinder 10.
However, if linearity of capacitance is not required, the enlarged diameter portion 14d may be omitted and the electrode portion 14a may be brought into contact with the inner peripheral surface of the insulating cylinder 10. can.

[Effects of the Invention] As described above, according to the present invention, since the female screw portion into which the screw portion of the movable electrode is screwed is configured by the coiled member having a polygonal contour inscribed in the terminal electrode, the coil The required operating torque of the movable electrode can be arbitrarily set simply by appropriately setting the internal dimension of the shaped member. Therefore, it is not necessary to provide a female screw portion and a slot in the terminal electrode, and the axial dimension of the terminal electrode can be reduced, thereby making it possible to downsize the trimmer capacitor.

Further, according to the present invention, since the insulating cylinder is fixed by being press-fitted into the terminal electrode, assembly can be facilitated, and manufacturing efficiency can be improved by automating the assembly of the trimmer capacitor. There are advantages.

Particularly, according to the present invention, by making the contour shape of the coiled member into a polygonal shape inscribed in the terminal electrode, each vertex of the outer peripheral part of the coiled member is brought into reliable contact with the terminal electrode, and the terminal electrode Since the shape of the coiled member is maintained by
Electrical connection between the coiled member and the terminal electrode can be stably established.

Further, in the present invention, the coiled member is formed into a polygonal shape so that the connection point between the threaded portion of the movable electrode and the coiled member is clearly determined, so that the electrical connection between the movable electrode and the coiled member is prevented. It can be done reliably.

Therefore, according to the present invention, the electrical connection between the coiled member and the terminal electrode can be made stable, and the electrical connection between the movable electrode and the coiled member can be made stable. Due to the synergistic effect, the electrical connection between the movable electrode and the terminal electrode can be ensured, and there is an advantage that variations in the electrical characteristics of the product can be reduced and quality can be stabilized.

Furthermore, in the present invention, since the coiled member is formed into a polygonal shape, the mechanical contact points between the coiled member and the movable electrode are clearly determined, so that the contact pressure at each contact point can be set to an appropriate level. By simply managing the internal dimensions of the coiled member, the required operating torque of the movable electrode can be easily kept within a predetermined range.

Furthermore, according to the second invention of the present application, the movable electrode is positioned concentrically with respect to the insulating cylinder by the screwing of the threaded part of the movable electrode and the coiled member and the contact between the enlarged diameter part of the movable electrode and the insulating cylinder. This eliminates center runout of the movable electrode, and the enlarged diameter portion of the movable electrode allows the electrode part of the movable electrode to be positioned so as not to come into contact with the insulating cylinder, so that displacement of the movable electrode in the axial direction This has the advantage that linearity of capacitance can be obtained with respect to the capacitance, and that a trimmer capacitor of excellent quality can be easily obtained.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention;
FIG. 2 is a sectional view taken along the line -- in FIG. FIG. 5 is a sectional view similar to FIG. 2 showing a modification of the coiled member used in the invention, and FIG. 5 is a longitudinal sectional view showing an example of a conventional trimmer capacitor. 10... Insulating cylinder, 11... Fixed electrode, 12...
...terminal electrode, 13...coiled member, 14...movable electrode, 14a...electrode part, 14b...screw part,
14d...Enlarged diameter part.

Claims (1)

[Claims] 1. an insulating cylinder made of a dielectric material, a cylindrical fixed electrode fitted on the outer periphery of one end of the insulating cylinder,
a terminal electrode disposed on the other end side of the insulating cylinder and fixed to the insulating cylinder; an electrode part inserted into the insulating cylinder and facing the fixed electrode via the insulating cylinder; and a male thread on the outer periphery. A trimmer capacitor comprising: a columnar movable electrode that is integrally formed with a threaded part having a engraved part thereon, and the threaded part is electrically connected to the terminal electrode; The terminal electrode is formed in the shape of a cylindrical body having an inner flange facing the other end face of the insulating cylinder, and is wound with a coil having an inner diameter and pitch that allows the threaded part of the movable electrode to be screwed into the coil. a coiled member is fitted on the inner periphery of the terminal electrode at a position adjacent to the inner flange, and the coiled member constitutes the female screw portion; and the insulating cylinder is press-fitted inside the terminal electrode and fixed. A trimmer capacitor, wherein the coiled member is formed to have a polygonal contour inscribed in the terminal electrode, and a screw portion of the movable electrode is screwed into the coiled member. 2. an insulating cylinder made of a dielectric material; a cylindrical fixed electrode fitted to the outer periphery of one end of the insulating cylinder;
a terminal electrode arranged on the other end side of the insulating cylinder and fixed to the insulating cylinder; an electrode part inserted into the insulating cylinder and facing the fixed electrode via the insulating cylinder; and a male thread on the outer periphery. The trimmer capacitor includes a columnar movable electrode that is integrally formed with a threaded part having a engraved part thereon, and the threaded part is electrically connected to the terminal electrode. The terminal electrode is formed in the shape of a cylindrical body having an inner flange facing the other end face of the insulating cylinder, and is wound with a coil having an inner diameter and pitch that allows the threaded part of the movable electrode to be screwed into the coil. a coiled member is fitted on the inner periphery of the terminal electrode at a position adjacent to the inner flange, and the coiled member constitutes the female screw portion; and the insulating cylinder is press-fitted inside the terminal electrode and fixed. the coiled member is formed to have a polygonal contour inscribed in the terminal electrode, the threaded portion of the movable electrode is screwed into the coiled member, and the outer part of the electrode portion of the movable electrode is An enlarged diameter portion having a diameter set smaller than the inner diameter of the insulating cylinder and contacts the inner circumference of the insulating cylinder is provided between the electrode portion and the threaded portion, and the enlarged diameter portion of the movable electrode and the insulating cylinder A trimmer capacitor characterized in that an electrode portion of the movable electrode is positioned concentrically with respect to the insulating cylinder by contact with the insulating cylinder.