JPS6242499Y2 - - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a slider for a variable resistor.

Conventionally, the sliders of variable resistors have been made as thin as possible in order to eliminate electrical noise caused by sliding.
For example, some wires are made by bundling a large number of wires with a diameter of about 0.08 to 0.10 mm using methods such as soldering or welding.

However, with this configuration, the wire material is expensive, and it requires advanced technology to accurately solder and weld the thin wire, which takes a lot of time and effort, and requires specialized equipment. There are drawbacks such as the need for

In order to solve this problem, parallel cuts are made from one end of a thin electrically conductive plate at fine equal intervals from one side edge, and fine widths are connected to each other at the other end of the thin plate. A slider may be considered in which a large number of fingers are formed and the fingers are brought into sliding contact with a resistor.

However, even if the above-mentioned drawbacks of this slider are solved, each time a cut is made, the cut fingers bend from the root, and in order to form a large number of fine widths with precision, it is necessary to correct the bend before making the next cut. It will have to be bent and unbent at least as many times as there are fingers before all the cuts are made. For this reason, the elasticity of the fingers decreases due to work hardening, which tends to cause electrical noise when sliding on a resistor, and the fingers tend to break.

In addition, when a thin plate formed of a large number of fine-width fingers arranged in parallel with each other in the width direction is used as a slider of a variable resistor as described above, the fingers arranged in parallel in the width direction can be used as arc-shaped resistors or collectors. It will slide on these resistors and collectors in a posture that crosses the axis in the radial direction, but when the adjustment knob is rotated, the finger on the inner circumferential side closest to the axis of the adjustment knob out of all the fingers Since the fingers on the outer circumferential side have different sliding contact speeds, the fingers on the outer circumferential side are shifted outward, and the intervals between the fingers become uneven, which causes noise. Furthermore, when the adjustment knob is rotated, a larger torsional stress acts on the fingers closer to the inner circumference, and there is a risk that the fingers closer to the inner circumference may be torsionally deformed.

In view of the above-mentioned problems, the present invention reduces the elasticity of the fingers by halving the number of bending and unbending operations when forming the fingers, and also prevents the inconvenience of the fingers coming apart or deforming during adjustment operations. , the purpose is to increase reliability.

For this purpose, the present invention is designed to reduce the width of the finger near the center in the width direction and the fingers on both outer sides in the width direction out of a large number of fingers formed in parallel with each other in the width direction at the end of the thin plate. Wider than the width of.

EMBODIMENT OF THE INVENTION Hereinafter, the structure of this invention will be described in detail about an Example based on drawing.

FIG. 1 is a partially cutaway perspective view of a variable resistor to which an embodiment of the present invention is applied.

In FIG. 1, 1 is a substrate made of alumina porcelain, 2 is a variable resistance adjustment knob made of electrically insulating resin, 3 is a collector, 4 is an arc-shaped cermet resistor, and 5 to 7 are external lead wires.

8 is a slider. As shown in FIG. 2, this slider 8 has a large number of parallel cuts 8c extending from one end 8a of a thin electrically conductive plate to the other end 8b.
It has a large number of fingers 8d, which are formed at minute intervals of, for example, about 0.10 mm. These fingers 8d, . . . are arranged in parallel in the width direction of the thin plate.

Among these fingers 8d..., the center finger 8e and the fingers 8f, 8f on both sides are wider than the other fingers 8d.... The entire slider 8 having such fingers is bent into a "T" shape, and one end 8
A curved portion 8g is formed on the a side. This curved part 8g
The lower surface is the surface that comes into sliding contact with the collector 3 and the resistor 4. In addition, this wide finger 8e, 8
Since f and 8f can be arranged so as not to contact the resistor 4, there is no risk of generation of sliding noise due to this even if the width is wide.

As described above, since this slider 8 has wide fingers 8e at least near its center, the slider 8 has fine fingers 8e as described below.
d... can be easily formed without them losing their elasticity and becoming easy to break.

FIGS. 3a and 3b are a plan view and a sectional view illustrating the formation of fingers in the manufacturing process of the slider 8. FIG.

First, a large number of convex templates 9 are prepared. Among these templates 9, the template 9 having the widest convex portion 9a is first applied to the back surface of the thin plate 10. A mold 11 is arranged so as to sandwich the thin plate 10 appearing on both sides of the convex portion 9a. By pushing this mold 11 in the direction of arrow B in FIG. 3b, the thin plate 10 is simultaneously cut from both sides thereof. As a result, two cuts 8c are simultaneously formed in the thin plate 10. Each time the template 9 finishes cutting the cuts 8c on both sides of the protrusion 9a, it is replaced with a template whose width of the protrusion 9a is one step smaller.

In this way, a large number of fingers 8d with fine widths are sequentially formed from both side edges of the thin plate 10 toward the center thereof. It is difficult to make the necessary convex portion 9a, for example, 0.1 mm wide due to the lifespan of the mold and the effects of fixing. Therefore, it is necessary to take measures such as making the last finger 8e twice as wide as the minute finger 8d. As a result, the last convex portion 9a can be made larger than the fine-width finger 8d, and the fine-width finger 8d can be formed up to the portion closest to the center. When the fingers are formed in this way, the number of times the fingers are bent is halved, the elasticity of the fingers is not impaired, and the performance as a slider is not impaired.

The slider 8 obtained as described above is inserted into the recess at the inner end of the adjustment knob 2, as already shown in FIG. Finger 8d of slider 8,...
are parallel to the arc-shaped resistor 4 and collector 3 in a direction (radial direction) that crosses them, and are in contact with these resistor 4 and collector 3 . In this state, when the adjustment knob 2 is rotated, the slider 8 pivots along the arc shape of the resistor 4 and the collector 3. In that case, the fingers 8d, ... located on the outer circumferential side have a faster moving speed, so they tend to deviate to the outside,
The finger 8f on the outermost periphery and the finger 8e near the center are wide and hardly shift outward, so the finger 8f on the inner side
d,... are restricted by these wide fingers 8f, 8e and do not shift outward. Therefore, the entire finger 8d does not come apart.

Furthermore, during the above adjustment operation, a large torsional stress acts on the innermost finger 8d, and this torsional stress may cause torsional deformation of the innermost finger 8d. Since the side fingers 8f are wide and difficult to deform, twisting deformation does not occur.

Since the slider 8 has a laterally symmetrical shape, the right side in FIG. 2 may be set as the inner periphery, or the left side may be set as the inner periphery.

As described above, according to the present invention, since the finger near the center is wide, when making a cut in a thin plate to form a finger, the part that becomes the center finger can be used as a support part for the cut, Two fingers can be formed at once by applying a template to the center and making cuts on both sides of the template. Therefore, compared to making cuts sequentially from one side of a thin plate to the other, the number of bending and unbending operations during finger formation is reduced by half, reducing work hardening and maintaining sufficient elasticity. It is possible to obtain a finger with a high degree of stability, and to manufacture a slider with high electrical reliability.

In addition, when rotating this slider on a resistor or collector by rotating the adjustment knob,
The fingers located on the outer periphery side tend to deviate outward and separate from each other, but the fingers located on the outermost periphery and the fingers near the center are wide,
Since there is almost no outward displacement, these fingers suppress the displacement of the fingers on the inside, preventing the fingers from coming apart as a whole, and preventing the generation of noise caused by the expansion of the fingers. Can be done.

Furthermore, the fingers on the inner circumference, where the greatest torsional stress is applied, are wide and difficult to deform, so there is no risk of twisting or deforming the fingers on the inner circumference during rotation operations, which also makes it reliable. Improves sex.

In addition, since the slider is symmetrical, either side can be set on the inner periphery, which facilitates the design of a variable resistor using this slider.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a partially cutaway perspective view of a variable resistor to which an embodiment of the present invention is applied, FIG. 2 is a perspective view of its slider, and FIGS. b
3A is a plan view, and FIG. 3B is a sectional view taken along line A--A in FIG. 3A. 8... Slider, 8c... Cut, 8d... Fine width finger, 8e, 8f... Wide finger, 9... Template, 10... Thin plate.

Claims (1)

[Scope of utility model registration request] Parallel cuts are made from the end of a thin plate having good electrical conductivity to form a large number of fine-width fingers arranged in parallel with each other in the width direction, and the fingers near the center of the end and the fingers on both outside sides in the width direction are formed. A finger is a variable resistor slider that is wider than other fingers.