JP2001076908A - Chip-type of variable resistor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent connection between terminals by a soldering ball, especially in a small chip-type of variable resistor. SOLUTION: In a chip-type of variable resistor, an intermediate terminal 6 is formed of a metal plate and has a flange part 6a provided with an eyelet part 6d, and a connection part 6b that is extended from the flange part 6a and has a bending part 6c at one end part. Furthermore, the flange part 6a is provided with a thin part that is thinner than the connection part 6b, so that the thin flange part 6a rises from the surface of a printed board 10. Thereby a soldering ball adheres less to the thin part of the flange part 6a, and the energization between a terminal 4 and the intermediate terminal 6 is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a chip-type variable resistor suitable for use in audio equipment and the like.

[0002]

2. Description of the Related Art As a conventional example, a chip-type variable resistor invented by the applicant of the present invention (Japanese Patent Application No. 11-104192) will be described with reference to FIGS.
10 to 10 show conventional chip-type variable resistors, FIG. 7 is an exploded perspective view, FIG. 8 is a cross-sectional view, FIG. 9 is an enlarged perspective view of a main part, and FIG. FIG. 4 is a cross-sectional view showing a state of attachment to the camera.

[0003] As shown in FIGS.
Is made of a ceramic material, is fired into a substantially rectangular shape, and has a very small size of about 2 mm square.
A circular through hole 31c provided at a central portion penetrating through the lower surface 31b, a recess 31d provided on the upper surface 31a so as to surround the through hole 31c, and a pair of protrusions 31f projecting from the side surface 31e. are doing.

The resistor 32 is made of, for example, a cermet-based paste, and is formed by printing or the like in a substantially arc shape around the recess 31d on the upper surface 31a of the insulating substrate 31. The pair of electrodes 33 is made of, for example, silver and glass frit, is substantially rectangular, is provided over the protrusion 31f of the upper surface 31a of the insulating substrate 31, is connected to both ends of the resistor 32, and the pair is formed by printing or the like. Is formed.

The terminal 34 is formed of a metal plate, and has a substantially rectangular bottom plate 34a and a pair of leg portions 3 which are orthogonal to the bottom plate 34a and bent upward from two adjacent side edges.
4b.

The terminal 34 has a bottom plate 34a in contact with the lower surface 31b of the insulating substrate 31, and legs 34b are arranged along two adjacent side surfaces 31e orthogonal to the corners of the insulating substrate 31. Further, the distal end of the leg 34 b is bent toward the upper surface 31 a of the insulating substrate 31, and the terminal 34 is attached to the insulating substrate 31. Then, the electrodes 33 and the terminals 34 are connected to each other and fixed by soldering 35.

[0007] The intermediate terminal 36 is a substantially rectangular bottom plate 3.
6a, a bent portion 36b cut and raised upward at one end of the bottom plate 36a, and a cylindrical eyelet portion 36c provided by drawing upward at an intermediate portion of the bottom plate 36a. Also, the intermediate terminal 36 is such that the bottom plate 36a is
In a state where the eyelets 36c are inserted into the through holes 31c of the insulating substrate 31, and the bent portions 36b extend in the direction of the upper surface 31a along the cutouts provided in the side surfaces 31e of the insulating substrate 31. Are located.

The slider 37 is made of a metal plate, is formed by drawing in a disk-shaped portion, and has a bottom wall portion 37 provided with a hole 37a.
b, and an operation unit 3 having a cross-shaped driver groove 37d bent from a part of the upper end of the cylindrical portion 37c and arranged above the cylindrical portion 37c.
7e and a substantially U extending downward from the outer periphery of the cylindrical portion 37c.
And a U-shaped sliding portion 37f.

The cylindrical portion 37c of the slider 37 is disposed in a recess 31d on the upper surface 31a of the insulating substrate 31, and the eyelet 36c of the intermediate terminal 36 is inserted into the through hole 31c of the insulating substrate 31. In this state, the tip of the eyelet 36c is inserted into the hole 37a of the slider 37, and the eyelet 36c
Is crimped, and the slider 37 is attached to the insulating substrate 3.
1 is rotatably held. At this time, the bottom plate 36a of the intermediate terminal 36 contacts the lower surface 31b of the insulating substrate 31, and the sliding portion 37f of the slider 37 resiliently contacts the resistor 32 provided on the upper surface 31a of the insulating substrate 31. ,
In accordance with the rotation of the slider 37, the sliding portion 37f
2 to slide on.

The operation of the chip type variable resistor having such a configuration is such that when a driver (not shown) as an operating tool is inserted into the driver groove 37d and the operating portion 37e is rotated, the cylindrical portion 37c is rotated. And the sliding portion 37f rotate at the same time, and the sliding portion 37f slides on the resistor 32 to adjust the resistance value.

Next, a method for mounting a conventional chip-type variable resistor on a printed wiring board will be described with reference to FIG. 10. The printed wiring board 40 is made of, for example, a synthetic resin material containing glass, or the like. Printed wiring board 40
A desired conductive pattern (not shown) is formed on at least one of the surfaces. The above-described chip type variable resistor is mounted on the conductive pattern (not shown) of the printed wiring board 40. At this time, cream solder (not shown) is applied on a predetermined conductive pattern, and the terminals 34 and the intermediate terminals 36 of the chip-type variable resistor are mounted so as to be connected to the cream solder.

In this state, the printed wiring board 40 on which the chip type variable resistor is mounted is transported into a reflow furnace, and
The terminals 34 and the intermediate terminals 36 of the chip-type variable resistor and the conductive pattern of the printed wiring board 40 are connected by solder 41.
At this time, the cream solder exists as a solder 41 for connecting the terminal 34 and the intermediate terminal 36 to the conductive pattern, respectively, and a solder ball 42 floating from the solder 41. And
When the solder ball 42 is located between the terminal 34 and the intermediate terminal 36 which are particularly small in distance, the two are electrically connected to each other, and the function as a variable resistor is not performed.

[0013]

In the conventional chip type variable resistor, the terminal 34 and the intermediate terminal 36 are simply provided on the insulating substrate 3.
The small-sized chip-type variable resistor has a problem in that the terminals 34 and the intermediate terminals 36 having a small distance are electrically connected to each other by the solder balls 42 because they are mounted on the lower surface 31 b of the first chip 31. Therefore, the present invention provides a chip-type variable resistor in which connection between terminals by solder balls is prevented, particularly in a small-sized chip-type variable resistor.

[0014]

As a first means for solving the above problems, an insulating substrate having a through-hole at the center and having a resistor formed on the upper surface, and a resistor at both ends of the resistor are provided respectively. A pair of terminals provided on a side surface of the insulating substrate in a connected state, a slider disposed on an upper surface of the insulating substrate and sliding on the resistor, and disposed on a lower surface of the insulating substrate; An intermediate terminal having an eyelet portion rotatably mounting the slider, the intermediate terminal is formed of a metal plate, a flange portion provided with the eyelet portion, extending from the flange portion, A connecting portion having a bent portion at one end; and a thin portion having a smaller thickness than the connecting portion is provided at the flange portion.

As a second solution, the thin portion of the flange portion is formed by tapping. As a third solution, the whole of the flange portion is formed by the thin portion.

As a fourth solution, an insulating film is formed on the surface of the thin portion. In addition, the fifth
As a means for solving the problem, a concave portion for receiving the flange portion and the connection portion of the intermediate terminal is provided on a lower surface of the insulating substrate, and a surface of the thin portion is located in the concave portion from a lower surface of the insulating substrate. Thus, the intermediate terminal was attached to the insulating substrate.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A chip type variable resistor according to the present invention will be described with reference to FIGS. 1 to 6. FIGS. 1 to 6 show a chip type variable resistor according to the present invention, and FIG. FIG. 2
Is a plan view, FIG. 3 is a side view, FIG. 4 is a bottom view, FIG. 5 is a cross-sectional view taken along line 5-5 in FIG. 2, and FIG. 6 is a cross-sectional view showing a state in which a chip type variable resistor is mounted on a printed circuit board. is there.

As shown in FIGS. 1 to 6, the insulating substrate 1
It is made of ceramic material and fired into a substantially rectangular shape, about 2m
Circular through hole 1c formed at the center part penetrating from upper surface 1a to lower surface 1b, having an extremely small size of m square.
A pair of protrusions 1f projecting from the side surface 1e;
And a rectangular concave portion 1h provided on the lower surface 1b including the position of the through hole 1c.

The resistor 2 is made of, for example, a cermet-based paste or the like, and has a through hole 1c formed on the upper surface 1a of the insulating substrate 1.
Is formed in a substantially arc shape by printing or the like. The pair of electrodes 3 is made of, for example, silver and glass frit,
A substantially rectangular shape is provided over the protrusion 1f of the upper surface 1a of the insulating substrate 1 and connected to both ends of the resistor 2, as in the conventional case, and a pair is formed by printing or the like.

The terminal 4 is made of a metal plate and has a substantially rectangular bottom plate 4a and a pair of legs 4b which are orthogonal to the bottom plate 4a and bent upward from two adjacent side edges.

The terminal 4 has a bottom plate 4a formed of an insulating substrate 1
The leg portion 4b is disposed along two adjacent side surfaces 1e orthogonal to the corners of the insulating substrate 1 and the tip portion of the leg portion 4b is The terminal 4 is attached to the insulating substrate 1 by being bent toward the upper surface 1a side of the substrate 1. Then, the electrodes 3 and the terminals 4 are connected to each other and fixed by soldering 5.

The intermediate terminal 6 is made of a relatively soft metal plate such as steel, and has a substantially rectangular flange portion 6a formed by a tapping process, and is extended to be connected to the flange portion 6a. A connecting portion 6b thicker than the flange portion 6a, a bent portion 6c cut and raised upward from one end of the connecting portion 6b, and a cylindrical portion provided by drawing upward at an intermediate portion of the flange portion 6a. And an eyelet 6d. Further, the intermediate terminal 6 has the flange portion 6a and the connection portion 6b located in the concave portion 1h of the lower surface 1b of the insulating substrate 1,
The eyelet 6d is in contact with the lower surface 1b,
c, and the bent portion 6c is inserted into the side surface 1e of the insulating substrate 1.
Are arranged so as to extend in the direction of the upper surface 1a along the notch provided in the upper surface.

The slider 7 is made of a metal plate such as stainless steel, which is harder than the intermediate terminal 6, is formed by drawing in a disk-shaped portion, and has a bowl-like cylindrical shape having a bottom wall portion 7b provided with a hole 7a. Part 7c and a part of the upper end of the cylindrical part 7c,
A cross-shaped driver groove 7 arranged above the cylindrical portion 7c
and a substantially U-shaped sliding portion 7f extending downward from the outer periphery of the cylindrical portion 7c.

The cylindrical portion 7c of the slider 7 is
And the eyelet 6 of the intermediate terminal 6
d is inserted into the through-hole 1c of the insulating substrate 1, the tip of the eyelet 6d is inserted into the hole 7a of the slider 7, and the tip of the eyelet 6d is crimped. 7 is rotatably held with respect to the insulating substrate 1. At this time, the thin portion of the flange portion 6a of the intermediate terminal 6 is located within the concave portion 1h of the insulating substrate 1, and the surface of the thin portion is recessed inside the concave portion 1h from the lower surface 1b of the insulating substrate 1; The sliding portion 7f of the slider 7 is elastically contacted with the resistor 2 provided on the upper surface 1a of the insulating substrate 1, and the sliding portion 7f is placed on the resistor 2 in accordance with the rotation of the slider 7. To slide.

An insulating film 8 made of an insulating material is formed on the surface of the flange 6a and in the hole of the eyelet 6d. The insulating film 8 is formed in the recess 1h of the insulating substrate 1 so as to be at least flush with the lower surface 1b, and the insulating film 8 is formed on the side of the intermediate terminal 6 close to the terminal 4. It is provided. The insulating film 8 may be formed on the entire surface of the flange portion 6a. In this embodiment, the entire flange portion 6a is formed as a thin portion. In particular, a thin portion may be provided near the terminal 4.

The operation of the chip type variable resistor having such a configuration is such that when a driver (not shown) as an operating tool is inserted into the driver groove 7d and the operating portion 7e is rotated, the cylindrical portion 7c is rotated. And the sliding portion 7f rotate simultaneously, and the sliding portion 7f slides on the resistor 2 to adjust the resistance value.

Next, a method of mounting the chip type variable resistor of the present invention on a printed wiring board will be described with reference to FIG. 6. The printed wiring board 10 is made of, for example, a synthetic resin material containing glass or the like, and has a flat shape. , Printed wiring board 10
A desired conductive pattern (not shown) is formed on at least one of the surfaces. The above-mentioned chip type variable resistor is mounted on the conductive pattern (not shown) of the printed wiring board 10. At this time, cream solder (not shown) is applied on a predetermined conductive pattern, and the terminals 4 and the intermediate terminals 6 of the chip-type variable resistor are mounted so as to be connected to the cream solder.

In this state, the printed wiring board 10 on which the chip type variable resistor is mounted is transported into a reflow furnace, and
The terminal 4 and the intermediate terminal 6 of the chip-type variable resistor and the conductive pattern of the printed wiring board 10 are connected by solder 11. At this time, the cream solder exists as a solder 11 connecting the terminal 4 and the intermediate terminal 6 to the conductive pattern, respectively, and a solder ball floating from the solder 11.

In the present invention, the connection portion 6b, which is a thick portion of the intermediate terminal 6, and the lower surface of the terminal 4 are mounted on the conductive pattern, and the flange portion 6a, which is a thin portion, floats from the surface of the printed circuit board 10. The flange 6
a, the adhesion of the solder ball on the thin portion is reduced.
And the intermediate terminal 6 is prevented from conducting.

When the concave portion 1h is provided in the insulating substrate 1 and the flange portion 6a and the connecting portion 6b of the intermediate terminal 6 are located in the concave portion 1h, the insulating substrate is located between the thin portion of the flange portion 6a and the terminal 4. 1 is present, and the intermediate terminal 6
The adhesion of the solder ball between the thin portion and the terminal 4 is further reduced, and conduction between the terminal 4 and the intermediate terminal 6 is prevented.

Further, when the insulating film 8 is provided, there is no adhesion of the solder ball between the thin portion of the intermediate terminal 6 and the terminal 4, and conduction between the terminal 4 and the intermediate terminal 6 is prevented.

[0032]

As described above, in the chip-type variable resistor according to the present invention, the intermediate terminal 6 is formed of a metal plate and has a flange 6a provided with an eyelet 6d, and extends from the flange 6a. Connecting portion 6b having bent portion 6c at one end
Since the flange portion 6a is provided with a thin portion thinner than the connecting portion 6b, the flange portion 6a which is a thin portion is provided.
Floats from the surface of the printed circuit board 10,
Adhesion of solder balls to the thin portion of the flange portion 6a is reduced, and conduction between the terminal 4 and the intermediate terminal 6 can be prevented.

Since the thin portion of the flange portion 6a is formed by tapping, the process is simple and the productivity is good. Further, since the entire flange portion 6a is formed of a thin portion, conduction between the terminal 4 and the intermediate terminal 6 is further prevented.

Further, since the insulating film 8 is formed on the surface of the thin portion, conduction between the terminal 4 and the intermediate terminal 6 can be completely eliminated. In addition, a concave portion 1h for receiving the flange portion 6a and the connection portion 6b of the intermediate terminal 6 is provided on the lower surface 1b of the insulating substrate 1, and the surface of the thin portion is located within the concave portion 1h from the lower surface 1b of the insulating substrate 1. Since the intermediate terminal 6 is attached to the insulating substrate 1, a part of the insulating substrate 1 exists between the thin portion of the flange portion 6 a and the terminal 4, and a portion between the thin portion of the intermediate terminal 6 and the terminal 4 is formed. The adhesion of the solder ball is further eliminated, and the conduction between the terminal 4 and the intermediate terminal 6 can be prevented.

[Brief description of the drawings]

FIG. 1 is a perspective view of a chip-type variable resistor according to the present invention.

FIG. 2 is a plan view of a chip-type variable resistor according to the present invention.

FIG. 3 is a side view of the chip type variable resistor of the present invention.

FIG. 4 is a bottom view of the chip type variable resistor according to the present invention.

FIG. 5 is a sectional view taken along line 5-5 in FIG. 2;

FIG. 6 is a cross-sectional view showing a mounted state of the chip-type variable resistor of the present invention on a printed circuit board.

FIG. 7 is an exploded perspective view of a conventional chip-type variable resistor.

FIG. 8 is a sectional view of a main part of a conventional chip-type variable resistor.

FIG. 9 is an enlarged perspective view of a main part of a conventional chip-type variable resistor.

FIG. 10 is a sectional view showing a state in which a conventional chip-type variable resistor is mounted on a printed circuit board.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insulating board 1a Upper surface 1b Lower surface 1c Through hole 1e Side surface 1f Projection 1g Depression 1h Depression 2 Resistor 3 Electrode 4 Terminal 4a Bottom plate 4b Leg 5 Solder 6 Intermediate terminal 6a Flange 6b Connection 6c Fold 6 d Moving element 7a Hole 7b Bottom wall 7c Cylindrical part 7d Driver groove 7e Operating part 7f Sliding part 8 Insulating film 10 Printed circuit board 11 Solder

Claims (5)

[Claims] 1. An insulating substrate having a through hole in the center and having a resistor formed on an upper surface thereof, and a pair of terminals provided on a side surface of the insulating substrate in a state of being connected to both ends of the resistor, respectively. A slider disposed on the upper surface of the insulating substrate and sliding on the resistor; and an intermediate terminal disposed on the lower surface of the insulating substrate and having an eyelet for rotatably mounting the slider. The intermediate terminal is formed of a metal plate, and has a flange portion provided with the eyelet portion, and a connecting portion extending from the flange portion and having a bent portion at one end portion, the flange portion A chip type variable resistor provided with a thin portion having a smaller thickness than the connection portion. 2. The chip-type variable resistor according to claim 1, wherein said thin portion of said flange portion is formed by tapping. 3. The chip type variable resistor according to claim 1, wherein the whole of the flange portion is formed by the thin portion. 4. The chip type variable resistor according to claim 1, wherein an insulating film is formed on a surface of said thin portion. 5. A lower surface of the insulating substrate is provided with a concave portion for receiving the flange portion and the connection portion of the intermediate terminal, and a surface of the thin portion is located within the concave portion from a lower surface of the insulating substrate. 5. The chip type variable resistor according to claim 1, wherein said intermediate terminal is attached to said insulating substrate.