JPH0556003B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a method of manufacturing a variable resistor that is used by being attached to a printed circuit board or the like.

(Prior Art) Conventionally, as shown in FIG. 1, a variable resistor of this type has been constructed using a wiper of a resistive substrate 3 having a collector electrode film 1 and a resistive film 2 concentrically formed on one main surface. Insert the shaft 5a of the adjustment screw 5 into the mounting hole 3a and the hole 4a provided in the wiper 4, caulk the tip of the shaft 5a,
A fitting groove (not shown) provided on the wiper 4 is connected to a fitting protrusion (not shown) provided on the adjusting screw 5.
It is generally known that the wiper 4 is attached to the resistance board 3 so as to be rotatable with the adjustment screw 4 by fitting the wiper 4 into the resistance board 3. Further, as shown in FIG. 2, in the variable resistor of FIG. 1, an eyelet 6 is used instead of the adjusting screw 5, and the blade of an adjusting driver (not shown) is inserted into the slit 4b provided in the wiper 4. It is also generally known that the wiper 4 can be directly rotated by inserting the wiper.

On the other hand, although not specifically shown, there is a shaft insertion hole in the center, the outer peripheral part of this insertion hole is bulged out to one side, and two arcuate holes are punched out on the outside of this bulged part. to form two arc-shaped spring parts, the central part of each arc-shaped spring part bulges to the one side, and both ends of each arc-shaped spring part are bent to the one side, and a circle is formed. Wipers have also been proposed in which the central part of the arcuate spring part is in sliding contact with the resistive film of the resistive board (for example,
(See Publication No. 20505).

The wiper has a tip of a shaft inserted between the collector electrode film formed on the resistance substrate and the lower surface of a rotating head for rotating the wiper, and inserted through the rotating head, the wiper, and the resistance substrate. is caulked to the resistor substrate, and the spring force of the arcuate spring portion is applied to the wiper with a rotational moment centered on both ends of the arcuate spring, causing the bulge of the wiper to bounce against the collector electrode film. I'm letting you touch me.

(Problems with the Prior Art) However, in the variable resistor having the structure shown in FIGS. 1 and 2, there is no elastic body such as a disc spring between the wiper 4 and the resistance board 3, and the adjustment screw 5
It is not possible to control the amount of caulking of the shaft 5a or the eyelet 6. Therefore, if the amount of caulking of the shaft 5a of the adjustment screw 5 or the eyelet 6 becomes large, cracks or cracks will appear in the resistance board 3, or the collector electrode film 1 will easily peel off when the wiper 4 rotates. The tightening force of
The torque becomes excessive. The rotation of the wiper 4 wears the caulked parts of the shaft 5a and the eyelet 6, causing the torque to decrease. The caulked parts of the shaft 5a and the eyelet 6 tend to crack, and the rotation direction of the wiper 4 causes The torque may be different or uneven torque may occur.
There were drawbacks such as poor torque feeling. On the other hand, when the above caulking amount becomes small, the adjustment screw 5 and eyelet 6 become loose, and the contact state between the wiper 4 and the collector electrode film 1 becomes unstable.The torque due to the rotation of the wiper 4 also decreases to the rated value, for example, 20 g. There were drawbacks such as splitting cm.

On the other hand, in the case where a rotational moment is applied to the wiper between the collector electrode film of the resistor substrate and the lower surface of the rotating head of the wiper, and the bulge part of the wiper is brought into elastic contact with the collector electrode film, As shown in the figure, a rotational moment acts on the wiper due to the spring force of the arc-shaped spring part, so the bulge part of the wiper does not come into contact with the collector electrode film with uniform force, and the contact between the wiper and the collector electrode film is The contact state is unstable, similar to the variable resistor in Figures 1 and 2,
Torque varies depending on the direction of rotation of the wiper,
There is a problem that torque unevenness occurs and the torque feeling deteriorates.Furthermore, with a small variable resistor, the wiper becomes smaller and the spring force of the arc-shaped spring part becomes smaller, so the bulge part of the wiper becomes smaller. The pressure contact force between the collector electrode film and the collector electrode film becomes weaker, and the above problem becomes more noticeable.

(Object of the Invention) An object of the present invention is to provide a method for manufacturing a variable resistor with excellent torque characteristics.

(Structure of the Invention) Therefore, in the present invention, the shaft of the adjustment screw is inserted into the wiper mounting hole provided in the resistance board and the hole provided in the wiper, and the wiper is attached to the resistance board so that it can rotate together with the adjustment screw. A method for manufacturing a variable resistor, which comprises: the resistor substrate; an adjusting screw having a stepped portion between the shaft and the screw head, the diameter of which is one step larger than the shaft; and a disc spring shape; Prepare a wiper whose depth is deeper than the height of the stepped part of the adjustment screw, and whose inner diameter at the opening end is slightly smaller than the diameter of the bottom surface of the screw head, and insert the shaft of the adjustment screw into the hole of the wiper. At the same time, insert it into the wiper mounting hole on the resistance board,
While the peripheral part of the wiper hole is brought into contact with the collector electrode film formed on the resistor substrate, the peripheral part of the wiper is brought into contact with the lower surface of the screw head near the periphery of the lower surface of the screw head of the adjusting screw, and the wiper is The tip of the shaft is deformed onto the resistor board until the gap between the outer peripheral portion of the hole and the stepped portion becomes almost zero, thereby preventing the shaft from slipping off the resistor board.

(Example) Hereinafter, an example of the present invention will be described with reference to the accompanying drawings.

The structure of a variable resistor manufactured according to the present invention is shown in FIGS. 3 and 4.

In FIG. 3 and FIG. 4 showing a cross section along the - line, 11 is a resistance board, 12 is an adjustment screw, and 13 is a wiper.

Similar to the variable resistor shown in FIG. 1, the resistance board 11 is a chip-shaped one made of an insulating material such as ceramic, and has a circular wiper mounting hole 11a provided approximately in the center thereof. . Resistance board 1
On one main surface of 1. A collector electrode film 14 is formed on the outer periphery of the wiper attachment hole 11a. Further, on the outside of the collector electrode film 14, the wiper mounting hole 11 is provided at a constant gap with the collector electrode film 14.
A horseshoe-shaped resistive film 15 is formed at a certain distance from the center of a.

The collector electrode film 14 is drawn out to a two-terminal electrode film 17 formed on a protrusion 16 located approximately at the center of one side of the resistor substrate 11, and both ends of the resistor film 15 are connected to both sides of the protrusion. Projections 18 and 1
It is drawn out to the one-terminal electrode film 21 and the three-terminal electrode film 22 formed at 9.

The adjusting screw 12 is made of a metal material such as red copper, and has exactly the same shape as the adjusting screw 5 of the variable resistor shown in FIG.

On the other hand, the wiper 13 is made by drawing and punching a metal plate having spring properties such as nickel silver, and as shown in FIG. 5a and FIG. Adjustment screw 1 provided
The peripheral portion 13b of the hole 13a through which the shaft 12a of No. 2 is inserted is pushed out downward to form the shape of a disc spring or a cap with a flange.

A flange-like member outside the peripheral part 13b of the hole 13a of the wiper 13, that is, a peripheral part (hereinafter referred to as the flange part) 13c of the wiper 13 is separated from each other by arc-shaped slits 13d and 13e, and has a central part. The contact portions 13f, 13f formed in the resistive film 15
(See FIGS. 3 and 4) Arm portions 13g, 13g to be slid are formed.

As shown in FIG. 4, the wiper 13 is located between the screw head 12b of the adjustment screw 12 and the resistance board 11, and when the tip of the shaft 12a of the adjustment screw 12 is caulked, the wiper 13 is The periphery 13 of the flange 13c and the hole 13a of the wiper 13
b are in pressure contact with the lower surface of the screw head 12b of the adjusting screw 12 and the collector electrode film 14 of the resistor substrate 11, respectively.

Note that the flange portion 13c of the wiper 13 has a fifth
As shown in Figure a and Figure 5b, the notch 13h
A fitting protrusion (not shown) of the adjusting screw 12 fits into the notch 13h, and the wiper 13 rotates together with the adjusting screw 12.

In the variable resistor having the structure explained above,
The wiper 13 is elastically interposed between the screw head 12b of the adjustment screw 12 and the resistance board 11, and the wiper 13
The peripheral portion 13b of the hole 13a is always pressed against the collector electrode film 14 of the resistive substrate 11 with a substantially constant elastic force. As a result, the peripheral portion 13b stably contacts the collector electrode film 14, and attenuation of the torque for rotating the wiper 13 is small.
Torque feeling also improves.

Incidentally, when the torque for rotating the wiper 13 of the variable resistor shown in FIGS. 3 and 4 is measured, as shown in FIG. 6, after rotating the wiper 13 in the hour hand direction (CW direction), Even if the cycle of rotation in the counterclockwise direction (CWC direction) is repeated, the torque exceeds the rated value of 20 g cm, and there is almost no attenuation, whereas with the variable resistor shown in Figure 1, the torque shown in Figure 7 It can be seen that if the wiper 4 is rotated once in the CW direction and then rotated again in the CCW direction, the torque will attenuate and fall below the rated value of 20 g·cm.

However, in FIGS. 6 and 7, the portion above the rotation speed axis indicates torque in the CCW direction, and the portion below the rotation speed axis indicates torque in the CW direction.

The variable resistor having the above structure is manufactured as follows. First, the resistance board 11, the adjustment screw 12, and the wiper 13 are prepared. Then, as shown in FIG. 8, the screw head 12b of the adjustment screw 12 is
With the shaft 12a facing down, insert it into the hole 13 of the wiper 13.
a and also into the wiper mounting hole 11a of the resistance board 11. Then, the tip is caulked with a caulking punch 23. At the initial stage of caulking, the peripheral part 13b and flange part 13c of the hole 13a of the wiper 13 are in contact with the collector electrode film 14 of the resistor board 11 and the screw head 12b of the adjusting screw 12, respectively. A gap g exists between the stepped portion 12c provided on the twelve shafts 12a. In the above state, as shown in FIG. 9, the punch 23 is lowered until the wiper 13 comes into contact with the stepped portion 12c of the shaft 12a, and then the crimping of the shaft 12a is stopped.

The stepped portion 12 of the shaft 12a of the adjustment screw 12
As can be seen from the above, c has a function of specifying the amount of caulking of the shaft 12a, thereby making it easy to manage the amount of caulking of the shaft 12a.

In the above embodiment, the resistance board 11 of the variable resistor may have a lead terminal (not shown) or the like, in addition to the chip-like one shown in FIG.

(Effects of the Invention) As is clear from the above detailed explanation, the present invention provides a wiper formed in the shape of a disc spring, the peripheral edge of which is screwed near the periphery of the lower surface of the screw head of the adjustment screw. The tip of the shaft is deformed by crimping it onto the resistor board until the gap between the outer periphery of the wiper hole and the step becomes almost zero while making contact with the lower surface of the head, making it compact. Even in a variable resistor, the size of the disc spring part is relatively large compared to the size of the wiper, and the necessary spring force can be secured. Then, the spring reaction force of the disc spring acts axially symmetrically on the axis of the adjustment screw, and the wiper always contacts the collector electrode film uniformly with almost constant pressure due to its elasticity, and the contact characteristics between the wiper and the collector electrode film, The torque characteristics, torque damping characteristics, and torque feeling of the wiper are greatly improved, and the caulking of the tip of the shaft of the adjusting screw can be easily managed by providing the shaft of the adjusting screw with a stepped portion that defines the amount of caulking.

In addition, even if cracks or the like occur in the crimped part of the shaft when the shaft is crimped, the crimped part of the shaft simply acts as a stopper for the resistance board to come off, so the cracks in the crimped part of the shaft can cause uneven torque and worsen torque feeling. can be eliminated.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views showing the structure of a conventional variable resistor, FIG. 3 is a plan view of an embodiment of the variable resistor according to the present invention, and FIG. 4 is a diagram showing the structure of a conventional variable resistor.
5a is a plan view of the wiper of the variable resistor of FIG. 3, and FIG.
6 is a torque characteristic diagram of the variable resistor shown in FIG. 3, FIG. 7 is a torque characteristic diagram of the variable resistor shown in FIG. 1, and FIGS. 8 and 9 are respectively shown in FIG. 3. FIG. 2 is an explanatory diagram of a method for manufacturing a variable resistor. 11...Resistance board, 12...Adjustment screw, 12a
...shaft, 12b...screw head, 13...wiper, 13a...hole, 13b...periphery, 13c...
...Brim portion, 14...Collector electrode film, 15...Resistive film.

Claims (1)

[Scope of Claims] 1. A variable resistor in which the shaft of an adjustment screw is inserted into a wiper mounting hole provided in a resistance board and a hole provided in the wiper, and the wiper is attached to the resistance board so as to be rotatable together with the adjustment screw. A method for manufacturing a resistor, comprising: the resistor substrate; an adjusting screw having a stepped portion with a diameter larger than the shaft between the shaft and the screw head; and an adjusting screw formed in the shape of a disc spring and having a depth. Prepare a wiper that is deeper than the height of the stepped part and whose inner diameter at the opening end is slightly smaller than the diameter of the bottom surface of the screw head, and insert the shaft of the adjustment screw into the hole of the wiper and insert it into the resistor board. Insert the wiper into the wiper mounting hole, and while bringing the peripheral part of the wiper hole into contact with the collector electrode film formed on the resistor board, place the peripheral part of the wiper so that the lower surface of the screw head is near the peripheral edge of the lower surface of the screw head of the adjusting screw. Make contact once and deform the tip of the shaft onto the resistor board until the gap between the outer periphery of the wiper hole and the step becomes almost zero to prevent the shaft from coming off the resistor board. A method for manufacturing a variable resistor.