JPH067524B2 - Variable electronic component manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention is preferably implemented in a chip type variable resistor whose resistance value can be adjusted, or a chip type variable capacitor whose capacitance can be adjusted. And a method for manufacturing a variable electronic component.

Prior Art A typical prior art chip variable resistor is shown in FIG. On the upper surface of the insulating substrate 2 having the through hole 1,
The resistance film 3 is formed in an arc shape with the through hole 1 as a center,
On the terminal plate 4 made of a metal plate arranged on the lower surface of the insulating substrate 2, a hollow shaft 5 fitted into the through hole 1 is integrally formed, and on the other hand, a metal plate made of a metal plate slidably contacting the resistance film 3 is formed. Slider 6
The slider 6 is rotatably attached to the hollow shaft 5 by spreading the end of the hollow shaft 5 into a trumpet shape and crimping the hollow shaft.

When the tip of the hollow shaft 5 is spread and crimped, a punch 9 having a conical tip 7 and an annular groove 8 is used as shown in FIG. It is performed by pressing the punch 9 against the tip of the hollow shaft 5. On the other hand, the hollow shaft 5 is work-hardened when integrally molding the hollow shaft 5 and the terminal plate 4, and when the end of the hollow shaft 5 is expanded and crimped by the punch 9, the hollow shaft 5 is attached to the end of the punch 9. If an excessive load is applied and caulking is repeated, punch 9
The conical tip 7 may be damaged.

Once the tip 7 of the punch 9 is damaged, the frictional resistance with the tip of the hollow shaft 5 increases, and an even greater load is applied to both the tip 7 of the porch 9 and the tip of the hollow shaft 5, causing caulking. The caulked portion 10 (see FIG. 10) obtained by processing may be deformed into an undesired shape. Therefore, the slider 6 can be attached to the hollow shaft 5 in a stable arrangement state. The problem of disappearing occurs. This means that the rotational torque of the slider 6 with respect to the hollow shaft varies depending on the rotational position, and the electrical and mechanical characteristics of the chip type variable resistor deteriorate.

The present invention has been made in view of the above problems, and it is possible to improve the reliability of the bonding state of the rotor member to the hollow shaft without deforming the crimped portion obtained by crimping into an undesired shape. An object of the present invention is to provide a method of manufacturing a variable electronic component that can be manufactured.

Means for Solving the Problems To achieve this object, the present invention provides a substrate having a through hole, a rotor member for adjusting a resistance value and the like, and a rotor member rotatable with respect to the substrate. A metal hollow shaft to be pivotally supported is prepared, the hollow shaft is inserted into a through hole of a substrate, and the rotor member is rotatably fitted to the tip of the hollow shaft, and then caulking means is attached to the tip of the hollow shaft. Pressed against,
In the method for manufacturing a variable electronic component in which the tip is expanded and caulking is performed, whereby a rotor member is rotatably attached to a hollow shaft, before caulking,
A notch was formed at the tip of the hollow shaft.

According to the present invention, since the notch is formed at the tip of the hollow shaft before the caulking process, when the caulking means is pressed against the tip of the hollow shaft during the caulking process, the tip of the hollow shaft is first The inner peripheral surface of which extends outward in the radial direction and spreads further, and when the caulking means is further pressed, the inner peripheral surface further extends outward in the radial direction and the notch is formed. Starts to tear, and while the avoiding portion becomes larger, the inner peripheral surface expands and the tip is expanded and caulked.

As described above, when the distal end of the hollow shaft is widened and crimped, the inner peripheral surface expands while avoiding the notch. Therefore, as much as the notch avoids as compared with the case where the inner peripheral surface is expanded only by extending. The load on the caulking means can be reduced. Therefore, the caulking portion is not deformed into an undesired shape due to an excessive load of the caulking means, and stable caulking can be always performed, and the rotor member can be stably attached to the hollow shaft.

Example Hereinafter, a case where an example of the present invention is applied to a chip type variable resistor will be described.

FIG. 1 is a vertical sectional view of a chip type variable resistor.
The figure is a plan view thereof, and FIG. 3 is a sectional view in an exploded state. The chip-type variable resistor has a through hole 1 at the approximate center.
A ceramic substrate 11 provided with 2 is provided, and a resistance film 13 is formed on the upper surface of the substrate 11 in an arc shape centered on the through hole 12. Terminals 15 and 16 for both ends of the resistance film 13 are formed on one side surface of the substrate 11. A central terminal plate 17 made of a metal such as stainless steel is provided on the lower surface of the substrate 11,
A hollow shaft 18 fitted in the through hole 12 is integrally formed in a portion of the center terminal plate 17 corresponding to the through hole 12.

On the substrate 11, there is provided a rotor member 19 for adjusting a resistance value, which is made of a metal plate and has an arm shape.
A sliding contact 20 that slides in contact with the resistance film 13 is formed integrally therewith, and a driver tool insertion groove 21 for rotating the rotor member 19 is provided therein. The rotor member 19 is rotatably fitted to the distal end of the hollow shaft 18, and then the hollow shaft 18 is caulked outward (this caulking portion is indicated by reference numeral 22).
It is rotatably attached to the hollow shaft 18. In addition, on the outer periphery of the caulking portion 22, a tearing portion 3 described later is formed.
1 is formed.

Next, the step of caulking the rotor member 19 to the hollow shaft 18 will be described.

First, as shown in FIG. 4, the center terminal plate 17 and the hollow shaft 18 are integrally formed at appropriate intervals during the transfer of the lead frame 24 in the longitudinal direction thereof, and then the next caulking step is performed. A pre-process for smoothing is carried out. That is, as the pre-step of the caulking step, the fifth step
As shown in FIG. 1A, a punch 25 whose tip 5a has a quadrangular pyramid shape is used, and the punch 25 is pressed against the hollow shaft 8 so that the inner peripheral surface of the tip 18a of the hollow shaft 18 is made. Four notches 26 are formed at equal intervals in the circumferential direction (see FIG. 5 (2)).

When the notch 26 is formed at the tip 18a of the hollow shaft 18,
The hollow shaft 18 is fitted with the substrate 11 and the rotor member 19, and as shown in FIG.
By using the punch 29 provided with 7 and the annular groove 28, and pressing the punch 29 against the tip 18a of the hollow shaft 18, the tip 18a of the hollow shaft 18 can be expanded and crimped in a trumpet shape. Thus, as shown in FIGS. 1 and 2, the rotor member 19 is rotatably attached to the hollow shaft 18.

FIG. 7 shows the tip 1 of the hollow shaft 18 in which the notch 26 is formed.
It is an enlarged plan view of 8a. The size of the notch 26 preferably satisfies the following conditions. That is, the width d1 of the notch 26 is selected so as to be much larger than the arcuate portion 30 of the inner peripheral surface of the tip 18a.
This is the punch 2 when the tip 18a is spread and crimped.
This is because the conical conical tip portion 27 of 9 slides smoothly inside the inner peripheral surface of the tip end 18a, and the pressure of the punch 29 is evenly applied in the circumferential direction of the inner peripheral surface. is there. The depth h1 of the notch 26 is the wall thickness D1 of the tip 18a.
It is chosen so that it is not too big compared to. this is,
This is to prevent the caulking portion 22 obtained by the caulking step from being torn too much from the notch 26 and making the mounting state of the rotor member 19 by the caulking portion 22 unstable. For example, when the inner diameter R1 of the tip 18a is 0.430 mm and the wall thickness D1 thereof is 0.090 mm, the width d1 of the notch 26 is 0.050 m.
The depth h1 of the notch 26 is preferably about 0.050 mm.

By providing such a notch 26, the punch 2
When 9 is pressed against the tip 18a of the hollow shaft 18, first the inner peripheral surface of the hollow shaft 18 begins to extend radially outward and spread,
When the punch 29 is further pressed, the inner peripheral surface further expands and spreads, and the portion where the notch 26 is formed begins to tear, and the inner circumferential surface widens while the teared portion grows, as shown in FIG. As shown in FIG.
8a is spread and crimped. Although the notch 26 is cut into the caulking portion 22 to form the slit portion 31, the notch 26 is provided with an appropriate size as described above, and therefore the slit portion 31 is too ripped and the caulking portion is formed. The attached state of 22 does not loosen.

As described above, when the distal end 18a of the hollow shaft 18 is widened and swaged, the inner peripheral surface expands while the notch 26 tears, so that the inner peripheral surface expands only by extending. The load applied to the punch 29 can be reduced to the extent that the notch 26 tears. Therefore, the rotor member 19 can be stably attached to the hollow shaft 18 without the pumping 29 being deformed into an undesired shape by the caulking portion 22 due to an excessive load. It is possible to prevent mechanical and electrical deterioration of the resistor. further,
Since the load applied to the punch 29 can be suppressed to be small, there is an advantage that the wear of the conical tip portion 27 of the punch 29 is reduced.

In the present embodiment, four notches are provided in the tip 18a, but the number of notches is not limited to four, and for example, as shown in FIG. 9, three notches 26a are equally spaced in the circumferential direction. May be provided so as to be opened. Further, the pre-processing for providing the notch 26 may be performed any time before the caulking processing. For example, it may be provided during the step of integrally forming the hollow sprue 18 on the central terminal plate 17. Good.

EFFECTS OF THE INVENTION As described above, according to the present invention, since the notch is formed on the inner peripheral surface of the end of the hollow shaft before the caulking process, when the end of the hollow shaft is widened and caulked, the cutting is performed. Since the inner peripheral surface expands while the notch tears, the load applied to the caulking means can be reduced by the amount of the notch tearing as compared with the case where the inner peripheral surface is widened only by extending. Therefore, the caulking portion does not deform into an undesired shape due to an excessive load of the caulking means,
The rotor member can be attached to the hollow shaft in a stable state, and deterioration of mechanical and electrical reliability of the electronic component can be prevented.

[Brief description of drawings]

1 is a vertical sectional view of a chip type variable resistor according to an embodiment of the present invention, FIG. 2 is a plan view of FIG. 1, FIG. 3 is an exploded sectional view, and FIG. 4 is a lead frame 24. FIG. 6 is a perspective view showing a state in which the center terminal plate 17 and the hollow shaft 18 are formed on the upper side, and FIG. 5 is a view showing a state in which a notch is formed at the tip of the hollow shaft in a step before the caulking step, The figure shows a state in which the hollow shaft is expanded and crimped, FIG. 7 is an enlarged plan view of the tip of the hollow shaft in which the notch 26 is formed, and FIG. 8 is the tip of the hollow shaft that is expanded and crimped. FIG. 9 is an enlarged plan view of FIG. 9 and shows a notch 2 of another embodiment of the present invention.
6a is an enlarged plan view of the tip 18a of the hollow shaft 18 in which 6a is formed, FIG. 10 is a vertical cross-sectional view of a conventional chip type variable resistor,
FIG. 11 is a diagram showing a state in which a hollow shaft is expanded and caulked in a conventional chip type variable resistor. 11 ... Substrate, 12 ... Through hole, 18 ... Hollow shaft, 19 ... Rotor member, 26 ... Notch, 29 ... Punch

Claims (1)

[Claims] 1. A substrate having a through hole, a rotor member for adjusting a resistance value and the like, and a metal hollow shaft for rotatably supporting the rotor member with respect to the substrate are prepared. After inserting the hollow shaft into the through hole of the substrate and rotatably fitting the rotor member to the end of the hollow shaft, press the caulking means against the end of the hollow shaft, expand the end, and perform the caulking process. In the method of manufacturing a variable electronic component for rotatably mounting a rotor member on a hollow shaft, a variable electronic device including a step of forming a notch at a tip of the hollow shaft before the caulking process. Manufacturing method of parts.