JPS6214644Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semi-fixed variable resistor, and more particularly to a small-sized semi-fixed variable resistor mounted on a printed circuit board.

Conventionally, in this type of small semi-fixed variable resistor, a slider provided on a rotating shaft contacts a resistor provided on an insulated substrate, and the slider on the resistor is moved by rotation of the rotating shaft. The contact point moves to change the resistance value, and the diameter is usually extremely small, about a few millimeters, and the insulating substrate is used to connect lead wires to the resistor and slider. A solder attachment part is provided, and the upper part of the slider is covered with a drive body for rotating the slider.

When installing such a semi-fixed variable resistor on a printed circuit board, if you try to connect lead wires, etc. to the solder attachment part, the solder may adhere to the slider, driver, rotating shaft, etc., and damage them. It may become impossible to rotate.

Furthermore, it is necessary to determine during the manufacturing process whether the semi-fixed variable resistor is securely attached to a predetermined position on the printed circuit board, but it is cumbersome to perform this through a surface inspection. Therefore, a method of irradiating light onto the printed circuit board and determining it based on its reflection has been considered, but conventionally, the driving body is made of zinc die-cast and the rotating shaft is made of copper. It was not suitable for detection.

This invention was made in view of the above drawbacks,
The purpose of this invention is to provide a semi-fixed variable resistor that prevents solder from adhering to the drive body that also serves as a cover for the slider, the rotating shaft, etc., and also allows the installation position to be confirmed by irradiation with light. The configuration includes a rotating support shaft that is inserted through an insulating substrate and supports a slider, and a driving body that is attached to the rotating support shaft and covers the slider, and a resistor provided on the insulating substrate and the The semi-fixed variable resistor is in contact with a slider and has a solder attachment portion formed on the surface of the insulating substrate close to the rotating shaft and the driving body, wherein the surfaces of the rotating shaft and the driving body are plated with chrome. It is characterized by having undergone.

An embodiment of the present invention will be described below based on the drawings.

The drawings all show embodiments of the present invention; FIG. 1 is a cross-sectional view of a semi-fixed variable resistor, FIG. 2 is a top view,
FIG. 3 is a bottom view.

In the figure, a resistor 2 is placed on a rectangular insulating substrate 1.
The resistor 2 is attached in a U-shape, and the current collector 3 is arranged separately from the resistor 2 in the center of the U-shape. Insulating substrate 1
An external printed circuit board (not shown) is attached to both ends of the outer periphery of the
Solder attachment parts 4 and 5 are provided for connection to the upper lead wires, one solder attachment part 4 is connected to the current collector 3, and the other solder attachment part 5 is connected to the insulating substrate 1.
It is connected to the solder attachment part 4 by a lead part 5a coated with an insulating coating on the back surface of the lead part 5a.

Further, a recess 1a is provided in the center of the back surface of the insulating substrate 1, and a hole 1b is bored in the center of the recess 1a, and a rotating shaft 7 supporting a ring-shaped driving body 6 is inserted into the hole 1b. are doing. The rotation support shaft 7 is made of copper plated with chrome, and has a flange portion 7a and a drive groove 7b at the rear end.
engages with the recess 1a of the insulating substrate 1. The drive body 6 is a die-cast zinc product with chrome plating, and the tip of the rotating shaft 7 penetrates the central cylindrical portion 6b, pushing the driving groove 6a and the hole 7c at the tip of the rotating shaft 7. It is integrated with the rotating support shaft 7 by engaging with the expanding portion 7d.

A slider 8 made of a ring-shaped conductor having spring properties is disposed between the lower surface of the driver 6 and the insulating substrate 1.
The inner peripheral part of this slider 8 is the cylindrical part 6 of the drive body 6.
A contact piece 8a provided at one end is in contact with the lower surface of b, and is elastically installed on the resistor 2 on the insulating substrate 1, and a locking portion 8b at the other end
is engaged with the notch 6c of the drive body 6.

A spacer 9 made of a conductive ring-shaped member such as beryllium katsupa is interposed between the lower surface of the inner circumference of the slider 8 and the current collector 3 on the insulating substrate 1. is electrically connected to the slider 8 via this spacer 9.

The solder attachment parts 4 and 5 are connected to the current collector 3 through electrodes 5b and 10, and other solder attachment parts are provided on the outer periphery of the insulating substrate 1 as shown in FIGS. 2 and 3. 11 and 12 are provided, and these solder attachment parts 11 and 12 are connected to both ends of the resistor 2 by electrodes 11a, 13, 12a, and 14 formed on the upper and lower surfaces of the insulating substrate 1.

Next, the operation of the semi-fixed variable resistor of the above embodiment will be explained.

When adjusting the resistance value, the drive groove 6 of the drive body 6
a or the drive groove 7b of the rotating support shaft 7, and rotate the jig. The slider 8 has a locking portion 8b with a notch 6
c, the contact piece 8a rotates accordingly, and the contact piece 8a slides on the resistor 2. Since the slider 8 is electrically connected to the current collector 8 via the spacer 9, the resistance value between the current collector 3 and the electrode of the resistor 2 changes due to this movement. Therefore, the resistance value between the electrodes can be set to a desired value.

Further, when fixing the semi-fixed variable resistor to a printed circuit board etc., the solder attachment parts 4, 5, 11,
Connect No. 12 to the lead wire and copper foil with solder. In this case, the surface of a rotating body such as the driving body 6 covering the slider 8 or the rotating shaft 7 which is outside the insulating substrate 1 and close to the solder attachment parts 4, 5, 11, 12 is Since it is covered with chrome plating, solder will not stick to it unnecessarily. Furthermore, if light is irradiated onto this resistor, the chrome plating will effectively reflect the light.

The present invention is as described above, and includes a rotating shaft that is inserted through an insulating substrate and supports a slider, and a drive body that is attached to the rotating shaft and covers the slider.
A semi-fixed variable resistor, wherein a resistor provided on the insulating substrate and the slider are in contact with each other, and a solder attachment portion is formed on the surface of the insulating substrate close to the rotating shaft and the driving body, the semi-fixed variable resistor comprising: It is characterized by chrome plating on the surfaces of the rotating shaft and the driving body.

Therefore, when connecting lead wires, etc. to the solder attachment part, the solder does not unnecessarily adhere to the drive body or rotating shaft, reducing malfunctions in the rotation of the resistor. Since it reflects light efficiently, the position of the resistor on the printed circuit board can be easily confirmed by light irradiation, which greatly improves work efficiency.

[Brief explanation of the drawing]

FIG. 1 is a front sectional view of a semi-fixed variable resistor according to an embodiment of the present invention, FIG. 2 is a top view of the semi-fixed variable resistor, and FIG. 3 is a bottom view of the semi-fixed variable resistor. DESCRIPTION OF SYMBOLS 1...Insulating board, 2...Resistor, 4...Solder attachment part, 5...Solder attachment part, 6...Driver, 7...
Rotating shaft, 8...Slider, 11...Solder attachment part,
12...Solder attachment part.

Claims (1)

[Scope of utility model registration request] A rotating support shaft that is inserted through an insulating substrate and supports a slider, and a driving body that is attached to the rotating support shaft and covers the slider, and a resistor provided on the insulating substrate and the slider. a semi-fixed variable resistor in which a solder attachment portion is formed on the surface of the insulating substrate close to the rotating shaft and the driving body, the surfaces of the rotating shaft and the driving body being chrome-plated. A semi-fixed variable resistor characterized by: