JPH0845711A - Variable resistor - Google Patents

Abstract

PURPOSE:To enable a precise resistance control from surface and rear in a simple structure even in a compact resistor. CONSTITUTION:A variable resistor is provided with a substrate 1 with a resistor formed thereon while a resistance adjusting konb 6 integrally formed of a rotary axle 13 is provided on the surface side of the substrate 1. On the other hand, the front end of the rotary axle 13 inserted into the rear surface side of the substrate 1 is cylindrically formed wherein mutually opposing notch parts are provided. In such a constitution, a driver slot 16 having abutting parts 14a, 14b of the end and side of the driver front end part from the notch part to the konb 6 side is formed on the rotary axle 13 of the base end part of the notch part 14b so that this notch part 14d may be molten down to be fan-likely folded back to the fitting part 12 of an intermediate terminal 11 to the formation of a pair of molten parts with the front end of the fan-like part abutted against the surface of said fitting part 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable resistor in which a slider slides on an arcuate resistor to change its resistance value.

[0002]

2. Description of the Related Art Conventionally, among variable resistors that change their resistance values by rotating a slider on an arc-shaped resistor, the one whose resistance can be adjusted from both front and back sides is usually the front side. A driver slot is provided on the adjustment knob, and a driver slot on the back side is formed in a portion where the central axis of the resistance adjustment knob is exposed on the back side of the substrate, which enables resistance adjustment from both front and back directions.

Further, in a variable resistor which is small and in which a driver slot cannot be formed in the central axis on the back side of the substrate, a metal plate having the driver slot is inserted from the back side of the substrate and engaged with the slider. Allows resistance adjustment.

[0004]

In the case of the above-mentioned conventional technique, due to the increasing demand for miniaturization of electronic parts in recent years, the central axis on the back side of the board of the adjusting knob has a margin for forming a driver slot. There is a problem of disappearing.

Further, the one in which the metal plate for the driver slot is engaged with the slider from the back surface side of the substrate has a problem that the number of parts is increased and the cost and the number of assembling steps are increased. Also, by forming a cross-shaped through hole on the adjustment knob,
It is possible to insert the driver from the back side as well, but the driver slot formed by the through hole will fit deeply into the slot when the driver is inserted and the rotation is adjusted. Moreover, since the driver is usually thicker toward the base end side, if you insert the driver into a small through hole, the driver will be inserted to the position where it will fit tightly into the slot, and it will be necessary to remove the driver after adjustment. There is a drawback that it takes time. Further, if the play after the driver is inserted into the slot is too large, it is difficult to finely adjust, and it is difficult to set the slot space.

The present invention has been made in view of the above problems of the prior art. Even in a small variable resistor, the resistance can be accurately adjusted from both front and back sides with a simple structure, and the mechanical strength is also improved. An object of the present invention is to provide a variable resistor having a high value.

[0007]

SUMMARY OF THE INVENTION The present invention is a variable resistor whose resistance can be adjusted from both front and back surfaces of a substrate on which a resistor is formed, and which is integrated with a resistance adjustment knob provided on the front surface side of the substrate. The distal end portion of the moving shaft, which is inserted into the back surface side of the substrate, is formed into a cylindrical shape, and cut portions facing each other are provided in the cylindrical portion, and the rotary shaft of the base end portion of the cut portion is provided with the cut portion. A driver slot having an end face of the driver tip and an abutting part of the side face is formed toward the knob part side, and the bifurcated part is melted and folded back to the attachment part of the middle terminal in a fan shape to form a pair of fused parts. Is formed, and the tip end of the fan-shaped portion is formed in a state of substantially abutting on the surface of the attachment portion of the middle terminal.

[0008]

According to the variable resistor of the present invention, even if it is a small variable resistor having a thin rotating shaft, the tip of the driver can be inserted and rotated, and the resistance can be easily adjusted from the back side. The mounting strength of the adjustment knob is also increased.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In the variable resistor of this embodiment, as shown in FIGS. 2 to 7, a U-shaped resistor 2 having a carbon-based coating or a metal glaze coating is formed on a surface 1a of an insulating substrate 1 made of ceramics or the like. The slider 3 is attached above it. The contact point 4 formed in a part of the slider 3 is slidably contacted with the resistor 2 and is slidably contacted with an outer peripheral portion of a metal cylindrical bearing portion 5 fitted to the substrate 1 to be rotatable. It is provided. The slider 3 is provided in the storage portion 7 of the resistance adjusting knob 6 provided on the front surface 1 a side of the substrate 1, and the engagement piece 3 a of the slider 3 is the engagement recess 7 of the storage portion 7.
It is provided rotatably integrally with the resistance adjusting knob 6 by engaging with a.

The resistance adjusting knob 6 is made of a synthetic resin such as nylon. As shown in FIGS. 8 to 12, a cross-shaped driver slot 6a is formed on the front side and a slider is formed on the back side. An accommodating portion 7 such as 3 is formed. A cylindrical rotation shaft 13 that rotates around the bearing 5 is formed in the center of the back surface, and the tip end of this rotation shaft 13 has a gap width of 1.8 mm and cut portions facing each other. A forked portion 14 which is a forked portion formed by 14d is provided. The bifurcated portion 14 is formed in a cylindrical shape extending from the rotary shaft 13, has a bottom surface portion 14a and a side wall portion 14b, and has a predetermined depth from the tip portion to the middle of the side wall portion 14b. In order to facilitate melting and deformation in the assembling process, the side wall portion 14b is hollowed into a cylindrical shape to form a hollowed portion 14c.

Further, as shown in FIGS. 2 to 7, both ends of the resistor 2 are connected to electrodes 8a formed on the terminal connecting portions 8 of the substrate 1 and formed by firing glass silver paste or the like. There is. Attached portions 10 of terminals 9 projecting from the substrate 1 are connected to the respective electrodes 8 and soldered with solder 8b. Further, the bearing portion 5 on which the slider 3 is rotatably slidably in contact with the outer peripheral portion is integrally formed with the attachment portion 12 of the intermediate terminal 11 formed in the central portion of the back surface 1b of the substrate 1. The intermediate terminal 11 is connected to the mounting portion 12 through 90
It is bent and extends below the back surface 1b of the substrate 1.

A rib 17 is formed on each of the terminals 9 and 11 for increasing the strength, and one end of the mounting portion 12 is slidable as shown in FIG. 3, FIG. 5, and FIG. Pendulum 3
A stopper 18 is provided for restricting the rotation range of the. The stopper 18 is provided so as to protrude from the back surface 1b of the substrate 1 to the front surface 1a through the through hole 1c formed in the substrate 1, so that the slider 3 can hit at a constant rotation angle. The intermediate terminal 9 formed integrally therewith is prevented from rotating when the resistance adjusting knob 6 is rotated.

Further, as shown in FIGS. 1 and 4 to 7, the rotating shaft 13 of the resistance adjusting knob 6 is rotatably fitted to the bearing portion 5 from the surface 1a side of the substrate 1. . Then, as shown in FIG. 1, the tip end portion of the rotary shaft 13 protruding toward the back surface 1b of the substrate 1 is, when the variable resistor is assembled,
It fits in the bearing portion 5 and is projected from the attachment portion 12 of the middle terminal 11. After that, the tip of the bifurcated part 14 is heated and melted by a jig, and as shown in FIGS. Then, the pair of fan-shaped melting portions 15 are formed on the back surface of the mounting portion 12 so that the resistance adjusting knob 6 does not come off from the substrate 1. The fan-shaped melted portion 15 is melted and deformed to the extent that its tip portion contacts the surface of the attachment portion 12 of the middle terminal 11. Here, in the bifurcated portion 14, a hollow portion 14c is formed up to near the back surface of the substrate, and a notch portion 14d is formed toward the knob 6 side to form the bifurcated portion 14. The side walls 14b of the cut portion 14d are such that planes parallel to each other face each other.

The bottom portion 14a of the bifurcated portion 14
The side wall portion 14b and the inner surface 5a of the bearing portion 5 form an abutting portion with which the end surface and side surface of the driver tip portion abut, forming a driver adjusting slot 16 on the back surface side of the variable resistor. . Here, the bottom surface portion 14a and the side wall portion 14b, which are a part of the rotation shaft 13, rotate, but the bearing portion 5 does not rotate. The attachment of the resistance adjusting knob 6 and the melting of the bifurcated portion 14 are performed by the terminals 9,
It may be before or after soldering 11.

In the variable resistor of this embodiment, the rear side resistance adjusting driver slot is not formed inside the rotary shaft 13, but the rotary shaft itself is divided into two parts. Therefore, it is possible to make the thickness of the central axis as much as the required width of the driver slot, and even if the rotation axis of a very small variable resistor is thin, a slot for driver adjustment can be formed on the back side. It is possible to adjust the resistance from the back side.

Further, since the hollow portion 14c is formed in the divided portion 14, the divided portion 14 is easily bent and expanded at the time of melting, so that the fan-shaped fused portion 15 can be reliably formed. In particular, the fan-shaped melting portion 15 is divided into two and engages with the attachment 12 on the attachment 12 on the back surface of the substrate for reliable manual operation to hold the member rotatably.

Further, in this embodiment, the resistance adjusting knob 6
Since the tip end of the rotating shaft 13 is melted and attached to the substrate 1, the lower end edge of the resistance adjusting knob 6 comes into contact with the substrate 1 without a gap, the rotation is smooth, and the dustproof effect is high.

The tip of the rotary shaft of the present invention melts as described above to form a retaining member, and FIG.
As shown in FIG. 3, when the resistance adjusting knob 6 is formed, the brim-shaped engaging portion 20 is integrally formed at the tip of the bifurcated portion 14,
When it is inserted into the bearing portion of the variable resistor, the bifurcated portion 14 is elastically deformed to be inserted into the bearing portion, and after the insertion, the locking portion 20 engages with the end edge portion of the bearing portion to prevent retaining. It may be something that is done.

This makes it possible to omit the step of melting and forming the tip end of the rotary shaft to prevent the resistance adjusting knob 6 from coming off, which reduces the number of steps, and simply inserts it into the bearing portion. Since it is only done, the insertion can be easily automated.

The bearing portion of the variable resistor according to the present invention is
In addition to the one integrally formed from the attachment portion of the intermediate terminal as in the above embodiment, the metal plate forming the slider may be deeply drawn to form the bearing portion. Further, the slot on the back surface side of the variable resistor of the present invention may be one in which the rotary shaft is divided into the slots with the full width thereof, and the divided portion may be divided into three or four. Needless to say. Further, the shape of the terminal and the shape and size of the driver slot can be arbitrarily determined, and are not limited to the above-mentioned embodiment.

[0021]

According to the variable resistor of the present invention, the slot used for adjusting the resistance on the back side is formed by dividing the tip end portion of the rotating shaft rotatably provided inside the bearing portion. Therefore, the width of the slot can be made as wide as the width of the rotary shaft, and the slot for driver adjustment can be formed on the back surface side even with a thin rotary shaft of a small variable resistor.
Further, a driver center cloth contact portion is formed in the driver slot, so that the rotation operation of the driver is easy and reliable with less rattling.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view on the back surface side of an embodiment of a variable resistor of the present invention.

FIG. 2 is a plan view of a variable resistor according to this embodiment.

FIG. 3 is a front view of the variable resistor of this embodiment.

4 is a cross-sectional view taken along the line AA of FIG.

FIG. 5 is a bottom view of this embodiment.

FIG. 6 is a plan view of the variable resistor of this embodiment with the resistance adjustment knob removed.

FIG. 7 is a sectional view taken along line BB of FIG. 2;

FIG. 8 is a plan view of a resistance adjustment knob of this embodiment.

FIG. 9 is a front view of the resistance adjustment knob of this embodiment.

FIG. 10 is a bottom view of the resistance adjustment knob of this embodiment.

11 is a cross-sectional view taken along line CC of FIG.

12 is a cross-sectional view taken along the line DD of FIG.

FIG. 13 is a front view of another embodiment of the resistance adjustment knob of the variable resistor according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Resistor 5 Bearing part 6 Resistance adjustment knob 13 Rotating shaft 14a Bottom part 14d Cut part 15 Melting part 16 Slot

Claims (2)

[Claims] 1. In a variable resistor capable of adjusting resistance from both front and back surfaces of a substrate on which a resistor is formed, a rotary shaft which is integrated with a resistance adjusting knob provided on the front surface side of the substrate is inserted into the rear surface side of the substrate. The distal end portion is formed in a tubular shape, and notches facing each other are formed in the cylindrical portion, and the notch of the driver tip is formed on the rotation shaft of the base end portion of the notched portion and further toward the knob portion side from the notched portion. A variable resistor, wherein a driver slot having an abutting portion is formed, and a peripheral edge portion of a tip end of the notch portion abuts a surface of a mounting portion of the middle terminal. 2. A variable resistor capable of adjusting resistance from both front and back surfaces of a substrate on which a resistor is formed is inserted into a back surface side of a substrate of a rotary shaft integrated with a resistance adjustment knob provided on the front surface side of the substrate. The tip end is formed in a tubular shape, and notches facing each other are formed in the cylindrical portion, and the rotation shaft of the base end of the notch is provided with an end surface of the driver tip from the notch toward the knob side. And a driver slot having a contact portion with which the side surface abuts, the cut portion is melted and folded back in a fan shape to the attachment portion of the middle terminal to form a pair of fusion portions, and the tip portion of the fan portion is the middle terminal. A variable resistor formed so as to substantially abut the surface of the mounting part of the.