JPS6225841Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a variable resistor, and particularly relates to an improvement in the support structure of a variable resistor in which the terminal is integrally molded with resin and the molded body is used as a resistance substrate.

Among variable resistors, those called semi-fixed variable resistors are generally small in size, and are usually supported by their terminals and mounted on a printed circuit board. Among such small-sized semi-fixed variable resistors, this invention is particularly advantageously applied to vertical variable resistors that can be adjusted from the side.

In conventional variable resistors, an alumina substrate, for example, has often been used as the resistance substrate. Terminals are usually held on and led out from such an alumina substrate. As described above, this terminal also provides a support structure for the variable resistor, so its holding form is required to have relatively high strength. In order to increase this strength, conventional techniques have been applied to the alumina substrate and the terminals. However, in the next so-called terminal-integrated molded variable resistor proposed as an alternative to the variable resistor containing an alumina substrate as described above, it is difficult to apply the above-mentioned workmanship, and it is necessary to support the terminal with the terminal. A problem was encountered regarding the strength of the structure.

The structure of the terminal-integrated molded variable resistor will be described with reference to FIGS. 1 to 5. The resistance substrate 1 has a substantially disk shape and is made of an insulating resin such as epoxy resin. The resistance board 1 is provided with an insertion hole 2 . The resistor board 1 has 2
One fixed side terminal 3, 4 and one variable side terminal 5
are fixed in a partially buried state. The fixed side terminals 3 and 4 each have a shape in which the tip of a band-shaped metal plate made of brass, iron, etc. is bent in two places in opposite directions, and each tip is exposed on the surface of the resistor board 1. Components 6 and 7 are configured.
The variable side terminal 5 is made of a metal plate made of brass, iron, etc., and includes a band-shaped portion and an annular portion continuously extending from the band-shaped portion, and an inner portion 11 of this annular portion is plate-shaped. is prominent. Part of the band is
It is bent so as to stand up, and a stopper 8 is formed there. For such fixed side terminals 3 and 4, exposed parts 6 and 7 and terminal parts 9 and 10 are
As for the variable side terminal 5, the resistance board 1 is arranged so that the inner portion 11 of the annular portion, the stopper 8, and the terminal portion 12 are exposed or protruded, respectively.
During molding, each terminal 3, 4, 5 is insert molded in advance.

On one surface of the resistance substrate 1, an arc-shaped resistance film 13 made of carbon, for example, is formed. The resistive film 13 is applied and baked onto the resistive substrate 1 so as to cover the exposed portions 6 and 7 of the fixed side terminals 3 and 4. A slider 14 is arranged on the resistive film 13.
The slider 14 is approximately disk-shaped, and an arcuate slit 15 is formed in a part of its periphery. The remaining portion where the arc-shaped slit 15 is formed is curved downward so as to act as a spring against the resistive film 13, and a portion protruding further downward is formed, in which a contact portion 16 is formed. . The entire center of the slider 14 has a dish-shaped concave portion, and a square hole is formed in this portion. Four tongue pieces 17 are formed with each side of this square hole as one side.
Each tongue piece 17 is inserted into the insertion hole 2 of the resistance board 1 and is caulked so as to embrace the inner portion 11 of the annular portion of the variable side terminal 5. As a result, the slider 14 is rotatably held relative to the resistance substrate 1. In order to limit such rotation of the slider 14 within a certain range, locking portions 18 and 19 that engage with the stopper 8 are provided.

In the terminal-integrated molded variable resistor shown as an example, the slider 1 is
4 to a portion having a fixed relationship with the resistor substrate 1 (for example, the inner portion 11 of the annular portion of the variable side terminal), the assembly is easy to mass produce.

When such a terminal-integrated molded variable resistor is constructed as a vertical type, the
As shown in the figure, each terminal 3, 4, 5 is led out from one end surface of the resistor board 1, and each terminal part 9, 10, 12 is all oriented in the direction in which the slider 14 extends. The parts are located at each vertex of the triangle. Then, it is attached to a printed circuit board or the like in the manner shown in FIG.

Referring to FIG. 6, the variable resistor main body 20 including a resistance board etc. is in an upright state, and each terminal 3, 4, 5 facing the same direction is inserted into a predetermined hole of a printed circuit board 21. , in this state, it is soldered with solder 22. In this state, when adjusting, the slider is rotated with a screwdriver in the direction shown by arrow 23 or arrow 24. At this time, a force in the direction of arrow 23 or arrow 24 is applied to main body 20 by the driver. This force acts to tilt the main body 20 using point A or point B as a fulcrum. Therefore, in such an adjustment operation, if too much force is applied, the terminals 3, 4, and 5 will bend and the main body 20 will be tilted. For example, when a force in the direction of arrow 23 was applied, it was confirmed that the terminals 3, 4, and 5 were bent in the manner shown in FIG. 7, and the main body 20 was tilted. If such inclination of the main body 20 occurs even with a slight force, it becomes a major hindrance to the adjustment operation.

In particular, the bending of the terminals 3, 4, and 5 at point A in FIG. 6 is a problem specific to the terminal-integrated molded variable resistor. That is, since this terminal-integrated molded variable resistor does not use an alumina substrate, it is not easy to modify the bases of the lead-out portions of the terminals 3, 4, and 5 to provide strength.

Therefore, the main purpose of this invention is to provide a variable resistor structure that can solve the above-mentioned problems peculiar to the integrally molded terminal type.

This invention is based on the above-mentioned terminal-integrated molded variable resistor, in which the lead-out portion of the terminal extends in the same direction as the adjustment direction, that is, to the side opposite to the adjustment side, and the upper edge thereof is connected to the resistor. A support part is formed so that the lower edge thereof is in contact with or faces the printed circuit board with a slight gap, and thereby When the support is adjusted while being attached to a printed circuit board, the upper edge of the support comes into contact with the end surface of the board, and the lower edge of the support comes into contact with the upper surface of the printed circuit board. It is a variable resistor that can handle the applied force.

Other objects and features of this invention will become clearer from the detailed description given below with reference to the drawings.

FIG. 8 is a perspective view of an embodiment of this invention.
When FIG. 8 is compared with FIG. 1 of the prior art, the features of this embodiment become clear. That is, the lead-out portions of the terminals 3 and 4 are provided with bent portions 3 as supporting portions.
0,31 are formed. The bent portions 30, 31 are planes substantially perpendicular to the planes 28a, 29a of the lead-out portions, which are extensions of the bases 28, 29 of the lead-out portions, and begin near the end face 25 of the board and are formed on the printed circuit board. The end is long enough to leave the part to be inserted. The bent portions 30 and 31 are, for example,
Terminals 3 and 4 are provided with corresponding protruding pieces.
is formed in advance from a metal plate, and the protruding pieces are bent. Bending portion 30, 3
The support portion exemplified in No. 1 may be formed by casting or the like in addition to the above-mentioned bending process.

The functions of the terminals 3 and 4 according to this embodiment will become clear from FIG. The upper edges of the bent portions 30 and 31 are close enough to touch the end surface 25 of the main body 20 including the resistance substrate 1. In addition, the lower edges of the bent portions 30 and 31 come into contact with the printed circuit board 21 when the terminals 3 and 4 are inserted into the printed circuit board 21, or
Otherwise, they are very close. Therefore, even if the force applied by the driver during adjustment is applied in the direction of the arrow 23, the upper edges of the bent portions 30, 31 contact the end surface 25, and the lower edges contact the printed circuit board 21, so that the main body 20 The slope of is suppressed to a certain limit. The load is not concentrated only at point A or point B in FIG. 6 as shown in the prior art. Therefore, in the variable resistor according to this embodiment, it is possible to prevent the terminals 3, 4, 5 from being bent at the base portions 28, 29, 27 due to the force applied during adjustment, so that the main body 20 is prevented from being tilted. It can withstand more force. Furthermore, terminals 3 and 4
Since it also has an L-shaped structure, the bending strength in the longitudinal direction increases, and accordingly, it becomes possible to prevent deformation during handling.

In this embodiment, the fixed side terminals 3 and 4 are provided with bent portions 30 and 31, but the present invention is not limited to this case. That is, as long as the bent portion is formed in the same direction as the adjustment direction and on the side opposite to the side to be adjusted, it may be provided on any terminal.

FIGS. 10 to 14 are for explaining other embodiments of this invention, respectively. Each embodiment will be described below, and points different from the above-mentioned embodiments will be explained in detail.

FIG. 10 is a side view showing the first other embodiment. As shown here, the variable side terminal 5 is bent at its base in the same direction as the direction in which the bending parts 30 and 31 extend. Further, the variable side terminal 5 has a bent portion 30,
It is bent at the same height as the lower edge of 31,
Its tip portion is approximately parallel to the tip portions of the terminals 3 and 4.

In this embodiment, when a force is applied from the direction of arrow 23 during adjustment, each terminal 3, 4, 5 is
bending is prevented. Furthermore, in this embodiment, when adjustment is made from the opposite direction, that is, when a force is applied from the direction of the arrow 24, the terminals 3, 4, 5 are moved from the base 2 due to the resistance to the extension of the variable side terminal 5.
8, 29, and 27 are prevented from being bent. That is, the variable resistor of this embodiment can effectively cope with the force applied during adjustment in any aspect.

FIGS. 11 and 12 are a side view and a bottom view for explaining a second alternative embodiment. Here, the bent portion 30 of one terminal 3 and the bent portion 31 of the other terminal 4 are formed by being bent in opposite directions. The variable side terminal 5 is bent at the base and extends in the same direction as the bent portion 31, as in the above embodiment. In this embodiment, when the adjustment is made in the direction of arrow 23,
The bending portion 31 contacts the end surface 25 of the main body 20 and the printed circuit board 21 to prevent each terminal 3, 4, 5 from bending. Further, when the adjustment is made in the direction of the arrow 24, the bent portion 30 comes into contact with the end surface 25 of the main body 20 and the printed circuit board 21, and each terminal 3, 4,
5. Prevents bending. Furthermore, when adjustment is performed in the direction of arrow 24, the adjustment force can be coped with by resistance to extension of variable side terminal 5. That is, in this embodiment, the bending part 31 effectively acts on the adjustment in the direction of the arrow 23, and the bending part 30 and the variable side terminal 5 act effectively on the adjustment in the direction of the arrow 24.

FIG. 13 is a side view for explaining the third other embodiment. This embodiment corresponds to a modification of the embodiment of FIG. That is, the bent portions 30 and 31 are the same except for their different shapes. Bending part 3
0 and 31 are provided with a protrusion 33 so that they can come into contact not only with the end surface 25 of the main body 20 but also with a plane 32 opposite to the adjustment direction. Therefore, this embodiment is the 10th example.
Compared to the illustrated embodiment, it is possible to cope with the forces applied during adjustment more firmly.

FIG. 14 is a bottom view showing a fourth alternative embodiment. Each terminal 3, 4, 5 is all bent part 30, 3
It has 1,34. Therefore, in this embodiment, when a force is applied during adjustment, the bending portions 30, 31, and 34 cope with the adjustment from any resistance. Note that the bent portions 30, 3 in this embodiment
The bending directions of 1 and 34 are not limited to the combination shown in FIG. That is, as long as bent portions that are bent in opposite directions are included, it is possible to handle adjustment from both directions using any combination.

As described above, according to this invention, each terminal is provided with a support portion formed by, for example, a bent portion, and the upper edge of the support portion is in contact with the end surface of the resistor board or has a slight gap. The terminals are formed so that they face each other with a gap between them, and the lower edges are formed so that they are in contact with the printed circuit board or face each other with a slight gap between them, so that each terminal does not bend due to the force applied during adjustment. This can be effectively prevented from occurring. In particular, in the case of terminal-integrated molded variable resistors, the resistance board is made of insulating resin such as epoxy resin, so the base of each terminal led out from the resistance board must be strengthened on the resistance board side. However, in this design, the upper edge of the support part is in contact with the end surface of the resistor board, so
It becomes possible to reliably suppress the inclination of the variable resistor body within a certain limit. Further, since the terminal having the bent portion has an L-shaped structure, the strength of the terminal itself can be increased. Therefore, it is also possible to effectively prevent undesired deformation of the terminal during handling or packing.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a prior art variable resistor of interest to the present invention. FIG. 2 is a perspective view of FIG. 1 with the slider removed. FIG. 3 is a perspective view of FIG. 2 with the resistive film removed. FIG. 4 is a sectional view of the buried portion of the fixed side terminal. FIG. 5 is a sectional view of the buried portion of the variable side terminal. FIG. 6 is a side view illustrating the force applied during adjustment. FIG. 7 is a side view illustrating a drawback of the variable resistor shown in FIG. 6. FIG. 8 is a perspective view of an embodiment of this invention. FIG. 9 is a side view for explaining one embodiment of this invention. 10th
The figure is a side view for explaining another embodiment of this invention. FIGS. 11 and 12 are a side view and a bottom view for explaining still another embodiment of this invention. FIG. 13 is a side view for explaining still another embodiment of this invention. FIG. 14 is a bottom view showing still another embodiment of this invention. In the figure, 1 is a resistance board, 3 and 4 are fixed side terminals, 5 is a variable side terminal, 6 and 7 are exposed parts, 13 is a resistance film, 14 is a slider, 20 is a variable resistor main body, 2
5 is an end face, 27, 28, 29 are base portions of lead-out portions of the terminals, and 30, 31 are bent portions serving as supporting portions.

Claims (1)

[Claims for Utility Model Registration] (1) Three terminals, two of which are fixed side terminals and the remaining one is a variable side terminal, and a portion of one end of each fixed side terminal is exposed on the surface. In this state, the resistor board is integrally molded including one end of each of the three terminals, and the three terminals are led out from one end surface, and the exposed part of each fixed side terminal is electrically connected at both ends. a resistor formed on the surface of the resistor board; and a slider having a contact portion that is electrically connected to the variable side terminal and slides on the resistor, the tip of the terminal being connected to the printed circuit board. In a variable resistor which, when inserted, is supported by its terminals above a printed circuit board with the direction in which the surface of the resistor board extends intersects with the direction in which the printed circuit board extends; At least one of them has a support part extending in the same direction as the adjustment direction and to the side opposite to the side to be adjusted, and the upper edge of the support part is in contact with the end surface of the resistor board or with a slight gap therebetween. The lower edges of the support portions are formed to be in contact with the printed circuit board or to be opposite to each other with a slight gap therebetween, thereby resisting the force applied by the adjustment. A variable resistor that prevents the board from being knocked over. (2) At least one terminal other than the terminal provided with the support part
The book terminal is bent at its base in the same direction as the support and further bent at the same height as the lower edge of the support so that the tip part is inserted into the printed circuit board. 2. The variable resistor according to claim 1, wherein the variable resistor is located at each vertex of a triangle together with the tip end portion of the terminal.