JP2572664Y2 - Semi-fixed resistor - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semi-fixed resistor, and more particularly to a semi-fixed resistor capable of minimizing an area required for mounting the semi-fixed resistor on a printed wiring board. It is.

[0002]

2. Description of the Related Art A conventional semi-fixed resistor includes an insulating substrate 71, a horseshoe-shaped resistor film 72 on the insulating substrate 71, and a A sliding member 73 having a sliding member 74 that slides, and a caulking member 75 including a pin portion 75a and a terminal portion 75b for rotatably holding the sliding member 73 on the insulating substrate 71. ing.

[0003] A horseshoe-shaped resistor film 72 is formed on an insulating substrate 71, and two terminal electrodes 72 a leading to one end of the insulating substrate 71 from both ends of the resistor film 72.
72b are formed. These two terminal electrodes 72a,
72b are formed on the front and back surfaces of the insulating substrate 71 and the end surfaces thereof, respectively. Further, the slider 7 that slides on the resistor film 72
The sliding body 73 having 4 is rotatably held by a caulking member 75. Note that a driver groove 76 for receiving an external rotation applying force is formed on the upper surface of the sliding body 73.

The above-mentioned semi-fixed resistor includes terminal electrodes 72a,
72b and the terminal portion 75b are soldered to predetermined electrode pads formed on the printed wiring board, respectively, and the sliding body 73 is rotated by a driver or the like in a circuit in the printed wiring board, so that the resistor film 72 is formed. The relative position of the slider 74 to the terminal electrode 7 on one end side of the resistor film 72 is different.
A resistance value is obtained between 2a, the terminal portion 75b of the sliding member 73, and the terminal electrode 72b on the other end side of the resistor film 72 and the terminal portion 75b of the sliding member 73.

[0005]

In the above-mentioned semi-fixed resistor, the terminal electrodes 72a and 72b are formed on a pair of one end surfaces of the insulating substrate 71 facing each other. Also, the terminal portion 75b
Are slightly protruded from the other pair of opposite end surfaces of the insulating substrate 71, and the ends thereof are bent in an L-shape.

When the solder is bonded to the terminal electrodes 72a, 72b formed on the end surface of the insulating substrate 71 or the terminal portion 75b whose tip is bent into an L-shape, the terminal electrodes 72a, 72b, the terminal A solder fillet is formed in which the solder rises in the height direction of the portion 75b.

Therefore, when an electrode pad connected to the terminal electrodes 72a and 72b and an electrode pad connected to the terminal portion 75b are formed on a printed wiring board for joining the semi-fixed resistor, the distance between the two electrode pads is reduced. Must be set to be equal to or greater than the length between a pair of opposed end faces of the insulating substrate 71,
Furthermore, in order to secure the formation area of the solder fillet,
Furthermore, it was necessary to increase the size in the direction opposite to the interval between the two electrode pads.

As a result, the area occupied by the mounting of the semi-fixed resistor including the electrode pad becomes unnecessarily large with respect to the shape (length and width) of the insulating substrate. However, there has been a restriction on the degree to which the wiring pattern has to be formed, and this has been a major obstacle to increasing the density of wiring patterns.

The present invention has been made in view of the above problems, and has as its object to provide a semi-fixed resistor capable of minimizing an occupied area required for mounting on a printed wiring board. It is in.

[0010]

The present invention achieves the above-mentioned object by concrete means for improving the structure and arrangement of a terminal portion connected to a slider and for connecting a terminal to a resistor film. This is achieved by adopting an improved electrode structure.

That is, the terminal portion connected to the slider that slides on the resistor film has a pair of bent portions on both sides in the width direction of the terminal portion to be in contact with the inner side surface of the concave portion on the bottom surface of the insulating substrate. Then, it is fitted and fixed in the concave portion of the insulating substrate.

Further, the terminal electrode connected to the resistor film is formed on an inner wall surface in a concave portion penetrating in the thickness direction of the substrate thickness on one end side of the insulating substrate.

[0013]

In the above-mentioned semi-fixed resistor, the semi-fixed resistor is connected to the end of the resistor film, is connected to the terminal electrode formed on one end of the insulating substrate and / or the slider, and is connected to the insulating substrate. The terminals arranged on the other end face each other and do not protrude from the end surface of the insulating substrate.

Therefore, the distance between the electrode pad for connecting to the terminal electrode and the electrode pad for connecting to the terminal portion can be made narrower than in the conventional case.

[0015] The solder fillet formed by the solder bonding has a terminal electrode side connected to the resistor film.
It is formed in a recessed portion that is recessed inward from the end surface of the insulating substrate, and on the terminal portion side connected to the sliding body, it is formed on the lower surface portion of the insulating substrate, so the shape of the electrode pad considering the solder fillet Can be suppressed substantially within the shape (length and width) of the insulating substrate of the semi-fixed resistor.

Due to the above two effects, when the semi-fixed resistor is mounted via the electrode pad of the printed wiring board, the occupied area required for mounting the semi-fixed resistor is substantially the shape (length) of the insulating substrate. (Width) is substantially the same as in the prior art, which can be minimized as compared with the conventional case, the degree of freedom of the wiring pattern formed on the printed wiring board is improved, and high-density wiring can be realized. Moreover, the terminal portion arranged in the concave portion on the bottom surface of the insulating substrate has a bent portion formed in a direction perpendicular to the extending direction of the terminal portion, and the bent portion contacts the inner wall surface of the concave portion, The terminal is fitted and arranged in the recess. Therefore, the terminal portion is stably arranged at a predetermined position on the bottom surface, and there is no displacement or the like.

[0017]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a semi-fixed resistor according to the present invention.

FIG. 1 is a top view of the semi-fixed resistor of the present invention, FIG. 2 is a cross-sectional view, FIG. 3 is a front view, and FIG. 4 is a bottom view. FIG. 5 is a plan view of the insulating substrate.

The semi-fixed resistor according to the present invention includes an insulating substrate 1,
A resistor film 2 formed on the insulating substrate 1, terminal electrodes 3a and 3b connected to the resistor film 2, and a slider 4 including a slider 5 sliding on the resistor film 2; And a caulking member 6 including a terminal portion 62 that rotatably holds the sliding body 4 on the insulating substrate 1 and electrically connects to the sliding body 4.

The insulator substrate 1 is made of alumina ceramic or the like. As shown in FIG. 5, a through hole 11 through which a caulking member 6 for rotatably holding the above-mentioned sliding body 4 penetrates is provided at the center thereof. Is formed. Quarter-circle recesses 12a and 12b are formed at corners on the end face side of the insulating substrate 1 on the side where the terminal electrodes 3a and 3b extend. Further, a through hole 11 is provided on the lower surface of the insulating substrate 1.
And a recess 13 extending toward the end face opposite to the end face on which the depressions 12a and 12b are formed.

On the insulating substrate 1, a horseshoe-shaped resistor film 2 is formed around the through hole 11 so as to match the sliding direction of the slider 5 of the sliding body 4. The horseshoe-shaped resistor film 2 is formed by printing, drying, and baking a resistor paste such as ruthenium oxide. This resistor film 2
Are extended to the vicinity of the recesses 12a and 12b of the insulating substrate 1 and connected to the terminal electrodes 3a and 3b.

The terminal electrodes 3a and 3b are made of Ag or Ag-
The conductive paste containing Pd as a main component is formed by printing, drying, and baking. Terminal electrodes 3a, 3b
Are formed around the recesses 12a and 12b appearing on the surface side of the insulating substrate 1 so as to be connected to both ends of the resistor film 2;
It is formed around the depressions 12a and 12b that emerge from the lower surface side of the insulating substrate 1 and further on the inner wall surfaces of the depressions 12a and 12b. Here, it is important that the terminal electrodes 3a and 3b are not formed on the surface corresponding to the end surface of the insulating substrate 1.

Incidentally, on the surface of the Ag-based thick conductor film constituting the terminal electrodes 3a and 3b, a film of Ni plating or solder plating is formed as necessary.

The slide body 4 is made of stainless steel or the like, and is formed, for example, in a dish-like shape as a whole, and a through hole 41 through which the caulking member 6 penetrates is formed in a central portion thereof. Driver grooves 42 are respectively formed. A slider 5 that slides and contacts at least on the resistor film 2 is formed on a part of the outer peripheral portion of the slider 4. The sliding body 4 including such a slider 5 is formed by press stamping and bending of stainless steel. Note that, in order to improve the mountability on the printed wiring board, an upper surface body that is folded back and covered may be formed on the upper surface of the sliding body 4. As a result, the upper surface of the sliding body 4 has a substantially planar structure, the suction performance by the vacuum chuck is improved, and the compatibility of the automatic mounting machine is facilitated. In this case, the driver groove 42 is formed in the upper surface body.

The caulking member 6 is made of stainless steel, nickel silver, or the like. 61, and a terminal portion 62 connected to the pin portion 61 and arranged in the concave portion 13 on the lower surface of the insulating substrate 1. In the pin portion 61 and the terminal portion 62,
Preferably, the lower surface of the terminal portion 62 is formed so as to protrude slightly below the lower end of the pin portion 61 so that the terminal portion 62 is stably connected to a predetermined electrode pad on the printed wiring board. Such a caulking member 6 is formed by press punching, bending, and cylindrical processing of a flat plate made of stainless steel, nickel silver, or the like.

It is important to note that the shape of the terminal portion 62 is arranged in the recess 13 on the lower surface of the insulating substrate 1, but is completely covered by the insulating substrate 1 and protrudes outward from the end surface of the insulating substrate 1. It is molded so as not to be done.

In order to stably arrange the terminal portion 62 in the concave portion 13 on the lower surface of the insulating substrate 1, bent portions 62a and 62b may be formed by bending both ends of the terminal portion 62 upward. . The bent portions 62a and 62b abut against the inner wall surface of the concave portion 13, and no displacement occurs in the left-right direction.

An insulating substrate 1 on which the resistor film 2 and the terminal electrodes 3a and 3b are formed, and a sliding member 4 having a slider 5
And the assembly with the caulking member 6 will be described.

First, the pin portion 61 of the caulking member 6 is inserted into the through hole 11 of the insulating substrate 1 from the lower surface side of the insulating substrate 1, and the terminal portion 62 is arranged in the concave portion 13 on the lower surface of the insulating substrate 1. Next, the pin portion 61 protruding from the surface of the insulating substrate 11
Is further inserted into the through hole 41 of the sliding member 4 and the tip of the slider 5 is arranged so as to be in contact with the resistor film 2. Finally, the tip of the pin portion 61 projecting into the recess of the dish-shaped sliding member 4 is crimped. As a result, the sliding body 4 is rotatably held on the insulating substrate 1.

Electrically, the slider 5 which comes into contact with the resistor film 2 is integrated with the caulking member 6 and is led out to a terminal portion 62 which is a part thereof. It is led out to terminal electrodes 3a and 3b connected to the ends.

Therefore, by inserting a driver or the like into the driver groove 42 of the sliding member 4 and rotating it by a predetermined amount,
The slider 5 slides on the resistor film 2, and depending on the contact position between the slider 5 and the resistor film 2, between the terminal portion 62 and the terminal electrode 3a or between the terminal portion 62 and the terminal electrode 3a. 3b becomes a predetermined value.

As described above, in the present invention, the terminal electrode 3
a, 3b are formed in quarter-circular recesses 12a, 12b formed in the corners of the insulating substrate 1, and the terminal electrodes 3a, 3b do not exist on the end surface of the insulating substrate 1.

The terminal portions 62 arranged along the lower surface of the insulating substrate 1 are arranged in the recesses 13 on the lower surface of the insulating substrate 1 and do not protrude outward from the end surface of the insulating substrate 1. .

Therefore, in order to mount the above-mentioned semi-fixed resistor on the printed wiring board, an electrode pad connected to the terminal electrodes 3a and 3b and an electrode pad connected to the terminal portion 62 are formed on the printed wiring board. However, the distance between the two electrode pads can be made within the length between the opposite end faces of the insulating substrate 1 of the semi-fixed resistor.

Therefore, the terminal electrodes 3a, 3b, the terminal portion 62
The occupied area required for mounting the semi-fixed resistor including the electrode pad to be joined with the electrode pad is reduced, the degree of freedom in routing the surface wiring pattern other than the electrode pad is improved, and high-density wiring can be realized.

The solder fillets formed by soldering the terminal electrodes 3a, 3b and the electrode pads to be bonded to the terminal portions 62 are formed in the recesses 12a, 12b at the corners of the insulating substrate 1 in the terminal electrodes 3a, 3b. Since the terminal portion 62 is formed on the lower surface portion of the insulating substrate 1, the above-mentioned occupied area does not substantially increase.

Accordingly, a reliable and strong solder joint can be achieved within an occupied area required for mounting the semi-fixed resistor.

[0038]

The terminal electrodes 3a, 3b of the above-described embodiment
Is formed in a corner portion of the insulating substrate 1 by a roughly 1/4 circular recess 12.
a, 12b are formed, but the point is that the terminal electrodes 3a, 3b
It is sufficient that b is depressed from the end surface of the insulating substrate 1 by an amount equal to or larger than the amount at which the solder fillet is formed. For example, in addition to the approximately 1/4 circle, the corners are approximately 1/4 elliptical, rectangular, triangular It does not matter. As shown in FIG. 6, not only the corners of the insulating substrate 1 but also the recessed portions 12c and 12d which are recessed in a rectangular shape are formed on the end surfaces of the insulating substrate 1, and the terminal electrodes 3a and 3b are formed on the inner wall surfaces. It does not matter. Further, in addition to the rectangular recesses 12c and 12d, a recess having a semicircular shape, a semielliptical shape, or a wedge shape may be formed.

[0040]

As described above, according to the present invention, each terminal electrode and the terminal portion are arranged in an occupied area required for mounting the semi-fixed resistor including the electrode pad on the printed wiring board connected to the terminal portion. Also, considering the solder fillet formed by solder bonding, the occupied area does not increase, so that the degree of freedom of the wiring pattern formed on the printed wiring board is improved, Wiring becomes possible. At the same time, the terminal portion can be stably arranged in the concave portion on the bottom surface of the insulating substrate without displacement.

[Brief description of the drawings]

FIG. 1 is a plan view of a semi-fixed resistor according to the present invention.

FIG. 2 is a sectional view of the semi-fixed resistor of the present invention.

FIG. 3 is a front view of the semi-fixed resistor of the present invention.

FIG. 4 is a bottom view of the semi-fixed resistor according to the present invention.

FIG. 5 is a plan view of an insulating substrate used in the semi-fixed resistor of the present invention.

FIG. 6 is a plan view of another insulating substrate used in the semi-fixed resistor of the present invention.

FIG. 7 is a plan view of a conventional semi-fixed resistor.

FIG. 8 is a sectional view of a conventional semi-fixed resistor.

[Explanation of symbols]

 1 ... Insulating substrate 11 ... Through-holes 12a, 12b, 12c, 12d ... Depression 13 ... ... Depression 2 ... Resistor films 3a, 3b ... Terminal electrode 4 Slider 5 Slider 6 Caulking member 61 Pin 62 Terminal

Claims (1)

(57) [Scope of request for utility model registration] 1. A horseshoe-shaped resistor film formed on an upper surface of an insulating substrate having a through hole, a slider sliding on the resistor film, and an end of the resistor film. And a terminal electrode formed at one end of the insulating substrate, and connected to the slider through a through hole of the insulating substrate.
A semi-fixed resistor comprising a terminal portion led to a concave portion on the bottom surface of the insulating substrate , wherein the terminal electrode is disposed in a thickness direction of an end surface on one end side of the insulating substrate.
When it is attached to the inner wall surface inside the recess formed so as to penetrate
Both, the width direction of the terminal portion on the bottom portion of the insulating substrate
A pair of bent portions abutting the inner wall surface of the recess on both sides
Wherein the terminal portion is fitted and arranged in the recess .