JP3209414B2 - Semi-fixed variable resistor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semi-fixed variable resistor capable of adjusting a resistance value at the time of assembling an electric circuit or after assembling, for example, and particularly to an improvement of a slider thereof.

[0002]

2. Description of the Related Art A semi-fixed variable resistor of this type is provided with a slider which is rotated by an adjusting tool such as a screwdriver, which has been disclosed in Japanese Patent Application Laid-Open No. 3-173404. As described above, there has been proposed a method in which an upper plate and a lower plate are individually formed from a thin metal plate, and then the two plates are integrated to form a slider. In this case, an engagement hole and a plurality of eyelet projections are formed on the upper plate to engage the adjustment tool, and a circular slide connected at the upper end to the bottomed tubular portion is formed on the lower plate. A moving plate is formed, and a sliding contact and a plurality of holes are formed in the sliding plate. Then, by inserting the eyelet projections of the upper plate into the holes of the lower plate and caulking, the upper plate and the lower plate are integrated to manufacture a slider.

The slider manufactured in this manner is mounted on a resistance substrate having a resistor formed on its surface, and a mounting bracket inserted from the back side into a through hole of the resistance substrate is attached to a cylindrical portion of a lower plate. By caulking, the slider is rotatably supported on the resistance board while making its sliding contact elastically contact the resistor. Therefore, after the semi-fixed variable resistor is mounted on the printed circuit board, if the adjusting tool is engaged with the engaging hole of the upper plate and the slider is rotated, the contact of the sliding contact on the resistor is achieved. The position can be changed to adjust the resistance value.

[0004]

In the above-mentioned conventional semi-fixed variable resistor, an engagement hole is formed in an upper plate superposed on the lower plate, and the engagement hole is formed in a cylindrical portion of the lower plate. Since the adjustment tool is located in the opening, the adjustment tool can be reliably engaged with the engagement hole, and the periphery of the engagement hole can be prevented from being deformed when the adjustment tool is rotated.

However, since the slider is formed by integrating the two members, the upper plate and the lower plate, which are separately formed, there is a problem that the number of parts increases and the assembly operation becomes complicated. In addition, when the upper plate and the lower plate are integrated, if the sliding plate formed in advance on the lower plate is deformed, there is a problem that the contact pressure of the sliding contact with the resistor varies. Further, since it is necessary to form a plurality of eyelet projections and holes on the opposing surfaces of the upper plate and the lower plate, there is a problem that it is difficult to cope with downsizing of the slider.

[0006]

SUMMARY OF THE INVENTION According to the present invention, an upper surface plate having an engagement hole and a lower member having a sliding plate are overlapped with each other via a folded portion to form an opening in a cylindrical portion of the lower member. The sliding element is formed by positioning the engaging hole inside. According to the slider configured as described above, the slider can be manufactured from one sheet of metal sheet, and it is possible to sufficiently cope with downsizing. To adjust the resistance value.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a semi-fixed variable resistor according to the present invention,
A resistor substrate having a through-hole and a resistor provided on the surface, a slider made of a thin metal plate provided with sliding contacts and engagement holes, and the slider inserted through the through-hole and A caulking member rotatably supported by the resistance substrate, and a contact point between the sliding contact and the resistor by rotating the slider by engaging an adjusting tool in the engagement hole. In the semi-fixed variable resistor that adjusts, the slider comprises a lower member and an upper plate integrated through a folded portion,
The lower member has a bottomed tubular portion that is larger in diameter than the through hole and is supported by the caulking member, and extends from the upper end side of the tubular portion toward the resistor and slides to the tip. A sliding plate having a contact point is provided, and the engaging hole is provided on the upper surface plate so as to face the bottom surface of the cylindrical portion at a predetermined interval .

The sliding plate may be bent obliquely at the upper end of the tubular portion. However, if an annular sliding plate is folded back at the upper end of the tubular portion and disposed around the tubular portion, The spring span from the folded portion of the sliding plate to the sliding contact can be lengthened while preventing the slider from increasing in size in the radial direction. At this time, the folded portion of the sliding plate and the tubular portion only needs to be displaced from the folded portion of the lower member and the upper plate, but if both folded portions are shifted to the opposing positions of approximately 180 degrees, the adjustment is performed. The torsional moment associated with the turning operation of the tool is less likely to act on the sliding plate, and deformation of the sliding plate can be reliably prevented.

[0009]

Embodiments will be described with reference to the drawings.
FIG. 1 is a plan view of a slider according to an embodiment of the present invention, and FIG. 2 is a sectional view of a semi-fixed variable resistor using the slider.

The slider 1 shown in these figures is made by folding a thin metal plate of a predetermined shape into three parts.
a, a cross-shaped engaging hole 2b is provided in the outer peripheral flat portion 2c.
The upper plate 2 is formed narrower, the middle upright plate 3 is provided with a caulking hole 3b at the bottom of a cylindrical portion 3a having a bottom, and an annular shape is formed to allow the cylindrical portion 3a to pass therethrough. It can be distinguished from the sliding plate 4 provided with the sliding contact 4a at the tip, and the lower member is constituted by the intermediate standing plate 3 and the sliding plate 4. here,
The outer peripheral flat portion 2c of the upper surface plate 2 is a cylindrical portion 3a of the intermediate upright plate 3.
The sliding plate 4 extends obliquely downward from the upper end surface of the cylindrical portion 3a via the second folded portion 6 on the upper end surface of the upper plate 2 via the first folded portion 5. And the sliding plate 4 are connected via the intermediate standing plate 3. Further, the outer peripheral flat portion 2c of the upper surface plate 2 is formed to be narrow, and the flat portion 2c
Is separated from the engaging hole 2b, and the bottom of the cylindrical portion 3a of the intermediate upright plate 3 is formed in a bowl shape.

As shown in FIG. 2, the slider 1 is rotatably supported on a ceramic substrate (resistance substrate) 8 by a stopper plate 7 made of a metal plate, and is assembled as a semi-fixed variable resistor. The ceramic substrate 8 is provided with a through hole 8a having a smaller diameter than the outer diameter of the bottom of the cylindrical portion 3a, and a resistor is formed on the surface of the ceramic substrate 8 so as to surround the through hole 8a. Then, the stopper plate 7 is inserted into the through hole 8a of the ceramic substrate 8 from the back side, and the caulking piece 7a provided at the upper end of the stopper plate 7 is inserted into the caulking hole 3b of the cylindrical portion 3a and caulked, thereby securing the stopper plate. The slider 1 held by 7 is rotatably supported on the ceramic substrate 8 with its sliding contact 4a elastically contacting the resistor. A lead plate 9 made of a metal plate is sandwiched between the back surface of the ceramic substrate 8 and the stopper plate 7, and a terminal (not shown) extends from the lead plate 9. Terminals, not shown, are also connected to both ends of the resistor.

The semi-fixed variable resistor constructed as described above is mounted on a printed circuit board, and then an adjusting tool such as a driver is engaged with the engaging hole 2b to rotate the slider 1 to rotate. In addition, the contact position of the sliding contact 4a on the resistor changes, and the resistance value can be adjusted. At this time, the engaging hole 2b is located within the opening of the cylindrical portion 3a, and a sufficient space is secured between the engaging hole 2b and the bottom of the cylindrical portion 3a. 2b can be securely engaged,
The rotation operation of the slider 1 becomes easy. In addition, the torsional moment associated with the turning operation directly acts on the throttle portion 2a of the upper plate 2, and the torsional moment does not directly act on the outer peripheral flat portion 2c separated from the engagement hole 2b. There is almost no possibility that the outer peripheral flat portion 2c having a weak mechanical strength will be deformed at the time of the rotation operation. Since the portions 6 are sufficiently separated, there is no possibility that this torsional moment acts on the sliding plate 4. Since the mechanical strength of the drawn portion 2a is increased by work hardening by drawing, the drawn portion 2a is not deformed even if it receives a torsional moment from the adjusting tool. In other words, since the outer peripheral edge of the narrowed portion 2a adjacent to the outer peripheral flat portion 2c of the upper surface plate 2 functions as a reinforcing rib, the flat portion 2c is prevented from being deformed.

In addition, the slider 1 used in the above embodiment has the following features.
The metal sheet can be easily formed by folding three metal sheets into three, and the first flat part 2c of the upper surface plate 2 and the upper end surface of the intermediate upright plate 3 form the first folded part 5 at the outer peripheral edge of both. Since they are connected via an intermediary, a fixing means such as an eyelet projection or a hole becomes unnecessary, which is suitable for reducing the diameter of the slider 1. Further, since the bottom of the cylindrical portion 3a of the intermediate upright plate 3 is bulged in a bowl shape toward the upper surface plate 2, the cylindrical portion 3a is formed.
Even when the substrate is directly mounted on the ceramic substrate 8, when the caulking piece 7a of the stopper plate 7 inserted into the caulking hole 3b is caulked, excessive stress concentration does not occur on the substrate 8 to avoid substrate cracking. Can be.

[0014]

The present invention is embodied in the form described above and has the following effects.

The slider is composed of a lower member integrated with a folded portion and an upper plate, and the lower member has a diameter larger than the through hole of the resistance substrate and is supported by a caulking member. A bottom-shaped tubular portion, and a sliding plate extending from the upper end side of the tubular portion toward the resistor on the resistor substrate and having a sliding contact at the tip are provided, and the bottom surface of the tubular portion is provided on the top plate. At predetermined intervals
When the engagement holes are provided so as to face each other, the slider can be easily manufactured from one sheet of metal sheet,
It is possible to sufficiently cope with downsizing, and it is possible to adjust the resistance value by securely engaging the adjustment tool with the engagement hole.

Further, when the annular sliding plate is folded back at the upper end side of the tubular portion and is disposed around the tubular portion, the folded portion of the sliding plate can be suppressed while preventing the slider from being enlarged in the radial direction. The spring span from to the sliding contact can be lengthened. At this time, if the folded portion of the sliding plate and the cylindrical portion is displaced by approximately 180 degrees with respect to the folded portion of the lower member and the upper plate, a torsional moment due to the turning operation of the adjusting tool causes the sliding plate. The deformation of the sliding plate can be reliably prevented.

[Brief description of the drawings]

FIG. 1 is a plan view of a slider according to an embodiment of the present invention.

FIG. 2 is a sectional view of a semi-fixed variable resistor using the slider shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Slider 2 Top plate 2a Restricted portion 2b Engagement hole 2c Flat outer periphery 3 Intermediate upright plate 3a Cylindrical portion 3b Swaged hole 4 Sliding plate 4a Sliding contact 5 First folded portion 6 Second folded portion 7 Stop plate (caulking member) 8 Ceramic substrate (resistance substrate) 8a Through hole

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01C 10/32

Claims (3)

(57) [Claims] 1. A resistance board having a through-hole and a resistor provided on the surface, a slider made of a thin metal plate provided with a sliding contact and an engagement hole, and said slider inserted through said through-hole. A caulking member that rotatably supports the slider on the resistance substrate, and engages an adjustment tool in the engagement hole to rotate the slider, thereby rotating the slider and the sliding contact. In a semi-fixed variable resistor that adjusts a contact position of a resistor, the slider includes a lower member and an upper plate integrated through a folded portion, and the lower member is more than the through hole. A large-diameter cylindrical part with a bottom supported by the caulking member, and a sliding plate extending from the upper end side of the cylindrical part toward the resistor and having the sliding contact at the tip are provided, respectively.
The semi-fixed variable resistor, wherein the engagement hole is provided in the upper surface plate so as to face a bottom surface of the cylindrical portion at a predetermined interval . 2. The device according to claim 1, wherein the sliding plate is integrated with the tubular portion via a folded portion,
A semi-fixed variable resistor, which is formed in an annular shape so as to surround the cylindrical portion. 3. The method according to claim 2, wherein the folded portion of the sliding plate and the tubular portion is displaced by approximately 180 degrees with respect to the folded portion of the lower member and the top plate. And a semi-fixed variable resistor.