JPH0732905U - Semi-fixed resistor - Google Patents

Abstract

(57) [Summary] [Object] The present invention provides a semi-fixed resistor capable of minimizing the occupied area on a printed wiring board. [Structure] Terminal electrodes 3a, 3 connected to both ends of a resistor film 2
b is a recess 12 formed on one end surface side of the insulating substrate 1.
It is a semi-fixed resistor formed on the inner wall portions of a and 12b. Further, it is a semi-fixed resistor in which the terminal portion 62 of the caulking member 6 connected to the slide body 4 including the slider 5 is arranged in the recess 13 formed in the lower surface of the insulating substrate 1.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a semi-fixed resistor, and more particularly to a semi-fixed resistor capable of minimizing the occupied area required to mount the semi-fixed resistor on a printed wiring board.

[0002]

[Prior art]

 As shown in FIG. 7 and FIG. 8, a conventional semi-fixed resistor includes an insulating substrate 71, a horseshoe-shaped resistor film 72 on the insulating substrate 71, and a sliding member that slides on the resistor film 72. It comprises a sliding body 73 having a moving element 74, and a caulking member 75 having a pin portion 75a and a terminal portion 75b for holding the sliding body 73 on the insulating substrate 71 in a rotatable manner.

A horseshoe-shaped resistor film 72 is formed on the insulating substrate 71, and two terminal electrodes 72 a and 72 b leading to one end of the insulating substrate 71 are formed from both ends of the resistor film 72. Has been formed. The two terminal electrodes 72a and 72b are formed on the front and back surfaces and the end surface of the insulating substrate 71, respectively. Further, the slide body 73 having the slider 74 that slides on the resistor film 72 is rotatably held by the caulking member 75. A driver groove 76 is formed on the upper surface of the sliding body 73 to receive an external turning imparting force.

In the above-mentioned semi-fixed resistor, the terminal electrodes 72a, 72b and the terminal portion 75b are soldered to predetermined electrode pads formed on the printed wiring board, respectively, and in the circuit in the printed wiring board, By rotating the sliding body 73 with a driver or the like, the relative position of the slider 74 with respect to the resistor film 72 is different, and the terminal electrode 72a on one end side of the resistor film 72, the terminal portion 75b of the sliding body 73, and the resistor A resistance value is obtained between the terminal electrode 72b on the other end side of the film 72 and the terminal portion 75b of the sliding body 73.

[0005]

[Problems to be solved by the device]

 In the above-mentioned semi-fixed resistor, the terminal electrodes 72a and 72b are formed on the pair of one end faces of the insulating substrate 71 that face each other. In addition, the terminal portion 75b slightly protruded from the pair of opposite end surfaces of the insulating substrate 71, and the tip thereof was bent into an L shape.

When solder is bonded to the terminal electrodes 72a and 72b formed on the end surface of the insulating substrate 71 and the terminal portion 75b whose front end is bent to have an L shape, the terminal electrodes 72a and 72b are connected. , A solder fillet is formed in which the solder rises in the height direction of the terminal portion 75b.

Therefore, when forming an electrode pad connected to the terminal electrodes 72a and 72b and an electrode pad connected to the terminal portion 75b on the printed wiring board for joining the semi-fixed resistor, when both electrode pads are connected, It is necessary to set the interval to be equal to or more than the length between a pair of opposed end surfaces of the insulating substrate 71, and to further increase the size in the direction opposite to the interval direction of the electrode pads in order to secure the formation area of the solder fillet. there were.

Eventually, the occupied area required to mount the semi-fixed resistor including the electrode pad becomes larger than necessary with respect to the shape (length / width) of the insulating board, and the wiring of the printed wiring board is There were restrictions on the degree of freedom, which was a major obstacle to increasing the density of wiring patterns.

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

[0010]

[Means for Solving the Problems]

 The concrete means for the present invention to achieve the above object is to improve the structure of the terminal portion connected to the slider side (first aspect) and to improve the structure of the terminal electrode side connected to the resistor film. This is achieved by adopting a structural improvement (second invention) and / or both.

That is, according to the first invention, a horseshoe-shaped resistor film is formed on an insulating substrate, a slider that slides on the resistor film, and an end portion of the resistor film are connected to each other and insulated. A semi-fixed resistor comprising a terminal electrode formed on one end side of a substrate and a terminal portion connected to the slider and arranged on the other end side of the insulating substrate, wherein the terminal Is a semi-fixed resistor having a portion disposed in a recess formed in the lower surface of the insulating substrate on the side of the other end.

A second invention is to connect a horseshoe-shaped resistor film on an insulating substrate, a slider that slides on the resistor film, and an end portion of the resistor film, and to insulate the resistor film. A semi-fixed resistor comprising a terminal electrode formed on one end side of a substrate and a terminal portion connected to the slider and arranged on the other end side of the insulating substrate, wherein the terminal electrode Is a semi-fixed resistor formed in a recess formed in the end surface on the one end side of the insulating substrate.

[0013]

[Action]

 In both of the above inventions, it is connected to the end of the resistor film and to the terminal electrode formed on one end of the insulating substrate and / or the slider, and to the other end of the insulating substrate. The arranged terminal portions do not project beyond the end faces of the insulating substrates facing each other.

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.

In addition, the solder fillet formed by solder joining is formed in a recessed portion that is recessed inward from the end surface of the insulating substrate on the terminal electrode side connected to the resistor film, and is connected to the sliding body. Since it is formed on the lower surface of the insulating substrate on the part side, even if the shape of the electrode pad that considers the solder fillet is used, it is substantially suppressed within the shape (length / width) of the insulating substrate of the semi-fixed resistor. be able to.

Due to both of the above actions, when the semi-fixed resistor is mounted via the electrode pad of the printed wiring board, the occupied area required to mount the semi-fixed resistor is substantially the shape (length) of the insulating substrate.・ The width becomes substantially the same as that of the conventional one, and it can be minimized compared to the conventional one, and the degree of freedom of the wiring pattern formed on the printed wiring board is improved, and high-density wiring can be realized.

[0017]

【Example】

 Hereinafter, the semi-fixed resistor of the present invention will be described in detail with reference to the drawings.

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

The semi-fixed resistor of the present invention comprises 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 the resistor. A crimping member having a slide body 4 including a slider 5 that slides on the film 2 and a terminal 5 that rotatably holds the slide body 4 on the insulating substrate 1 and that is electrically connected to the slide body 4. It consists of 6 and 6.

The insulating substrate 1 is made of alumina ceramic or the like, and 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 in the center thereof. Are formed. In addition, quarter circular recesses 12a and 12b are formed at the corners on the end face side of the insulating substrate 1 where the terminal electrodes 3a and 3b of the insulating substrate 1 extend. Further, on the lower surface of the insulating substrate 1, there is formed a recess 13 including the opening of the through hole 11 and extending toward the end surface side facing the end surface on which the recesses 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. Both ends of the resistor film 2 are extended to near 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 formed by printing, drying, and baking a conductive paste containing Ag or Ag-Pd as a main component. The terminal electrodes 3a and 3b are so formed as to be connected to both ends of the resistor film 2, the recesses 12a and 12b appearing on the front surface side of the insulating substrate 1, the recesses 12a appearing from the lower surface side of the insulating substrate 1, It is formed on the periphery of 12b and on the inner wall surfaces of the recesses 12a and 12b. Here, what is important is that the terminal electrodes 3a and 3b are not formed on the surface corresponding to the end surface of the insulating substrate 1.

If necessary, a Ni-plated or solder-plated film is formed on the surface of the Ag-based thick film conductor film forming the terminal electrodes 3a and 3b.

The sliding body 4 is made of stainless steel or the like, and is formed, for example, in a dish shape as a whole, and a through hole 41 through which the caulking member 6 penetrates is formed in the central portion of the slide body 4 and a dish-shaped insertion direction. A driver groove 42 is formed in each. Further, at least a part of the outer peripheral portion of the slide body 4 is formed with a slider 5 that slides on the resistor film 2. The slide body 4 including the slider 5 is formed by press punching and bending of stainless steel. In addition, in order to improve the mountability on the printed wiring board, an upper surface body that is folded back to cover 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 flat structure, the suction performance of the vacuum chuck is improved, and the automatic mounting machine can be easily handled. In this case, the driver groove 42 is formed in this upper surface body.

The caulking member 6 is made of stainless steel, nickel silver, or the like, and as a whole, penetrates the above-mentioned through holes 11 and 41, and has a tip protruding into the dish-shaped sliding body 4 and caulked. 61 and a terminal portion 62 connected to the pin portion 61 and arranged in the recess 13 of the lower surface of the insulating substrate 1. In the pin portion 61 and the terminal portion 62, the lower end of the terminal portion 62 is preferably slightly lower than the lower end of the pin portion 61 so that the terminal portion 62 can be stably connected to a predetermined electrode pad on the printed wiring board. It is molded so that it protrudes. Such a caulking member 6 is formed by press punching, bending, and cylindrical processing of a flat plate body such as stainless steel or nickel silver.

Here, it is important that the shape of the terminal portion 62 is arranged in the concave portion 13 of the lower surface of the insulating substrate 1, but is molded so as not to project outward from the end surface of the insulating substrate 1. ing.

It should be noted that bent portions 62 a and 62 b may be formed by bending both ends of the terminal portion 62 upward so that the terminal portion 62 is stably arranged in the recess 13 of the lower surface of the insulating substrate 1. . The bent portions 62a and 62b are in contact with the inner wall surface of the recess 13 and are not displaced in the left-right direction.

Assembly of the insulating substrate 1 on which the resistor film 2 and the terminal electrodes 3a and 3b are formed, the slide body 4 having the slider 5 and 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 recess 13 of the lower surface of the insulating substrate 1. Next, the pin portion 61 protruding on the surface of the insulating substrate 11 is further inserted into the through hole 41 of the sliding body 4 and arranged so that the tip of the slider 5 contacts the resistor film 2. Finally, the tip of the pin portion 61 protruding into the recess of the dish-shaped sliding body 4 is caulked. As a result, the sliding body 4 is rotatably held on the insulating substrate 1.

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

Therefore, by inserting a screwdriver or the like into the driver groove 42 of the slide body 4 and rotating the slide body 5 by a predetermined amount, the slider 5 slides on the resistor film 2 and the slider 5 and the resistor body Depending on the contact position with the film 2, the resistance value between the terminal portion 62 and the terminal electrode 3a or between the terminal portion 62 and the terminal electrode 3b becomes a predetermined value.

As described above, in the present invention, the terminal electrodes 3a and 3b are formed in the quarter-circular recesses 12a and 12b formed at the corners of the insulating substrate 1, and the insulating substrate 1 The terminal electrodes 3a and 3b are not present on the end face portion of the.

The terminal portion 62 arranged along the lower surface of the insulating substrate 1 is arranged in the recess 13 of the lower surface of the insulating substrate 1 and does not project outward from the end surface of the insulating substrate 1. Yes.

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

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

Further, the solder fillet formed by solder-bonding the terminal electrodes 3a and 3b and the electrode pad to be bonded to the terminal portion 62 has the recessed portions 12a and 12b at the corners of the insulating substrate 1 in the terminal electrodes 3a and 3b. In addition, since the terminal portion 62 is formed in the lower surface portion of the insulating substrate 1, the above-mentioned occupied area does not substantially increase.

Therefore, reliable and strong soldering is achieved within the occupied area required for mounting the semi-fixed resistor.

In the above-described embodiment, an example in which the first device of the arrangement structure of the terminal portion 62 and the second device of the arrangement structure of the terminal electrodes 3a and 3b are used at the same time is shown. The occupancy area required to mount the semi-fixed resistor can be minimized as compared with the conventional semi-fixed resistor simply by adopting either the above-mentioned arrangement structure or the arrangement structure of the terminal electrodes 3a and 3b. You can

Further, the terminal electrodes 3a and 3b of the above-described embodiment have the recessed portions 12a and 12b having a substantially 1/4 circular shape at the corners of the insulating substrate 1. It suffices that 3b is recessed from the end surface of the insulating substrate 1 by an amount equal to or larger than the amount by which the solder fillet is formed. It may be square. In addition to the corners of the insulating substrate 1, as shown in FIG. 6, rectangular recesses 12c and 12d are formed on the end surface of the insulating substrate 1, and the terminal electrodes 3a and 3b are formed on the inner wall surfaces thereof. It doesn't matter. In addition to the rectangular recesses 12c and 12d, a semi-circular, semi-elliptical, or wedge-shaped recess may be formed.

[0040]

[Effect of device]

 As described above, according to the present invention, it is possible to arrange the semi-fixed resistors including the electrode pads on the printed wiring board connected to the respective terminal electrodes and the terminal portion within the occupied area required for mounting. Also, even if the solder fillet formed by solder joining is taken into consideration, the occupied area does not increase, so the flexibility of the wiring pattern formed on the printed wiring board is improved and high density wiring is possible. Becomes

[Brief description of drawings]

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

FIG. 2 is a sectional view of a semi-fixed resistor according to 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 of 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 cross-sectional view of a conventional semi-fixed resistor.

[Explanation of symbols]

 1 ... Insulating substrate 11 ... Through hole 12a, 12b, 12c, 12d ... Recessed portion 13 ... Recessed portion 2 ... Resistor film 3a, 3b ... Terminal electrode 4 ・ ・ ・ Sliding body 5 ・ ・ ・ Slider 6 ・ ・ ・ ・ Caulking member 61 ・ ・ ・ Pin part 62 ・ ・ ・ Terminal part

Claims (2)

[Scope of utility model registration request] 1. A horseshoe-shaped resistor film formed on an upper surface of an insulating substrate, a slider that slides on the resistor film, an end of the resistor film, and one of the insulating substrates. A semi-fixed resistor comprising a terminal electrode formed on the end side and a terminal part connected to the slider and arranged on the other end side of the insulating substrate, wherein the terminal part is insulated A semi-fixed resistor arranged in a recess formed on the lower surface of the other end of the substrate. 2. A horseshoe-shaped resistor film formed on an upper surface of an insulating substrate, a slider that slides on the resistor film, an end of the resistor film, and one of the insulating substrates. A semi-fixed resistor comprising a terminal electrode formed on an end side and a terminal part connected to the slider and arranged on the other end side of the insulating substrate, wherein the terminal electrode is insulated from the terminal electrode. A semi-fixed resistor formed in a recess formed in the end surface on the one end side of the substrate.