JPH0325002B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a small variable resistor mainly used in small consumer electronic equipment such as audio equipment such as headphone stereos and portable radios, and video equipment such as micro televisions and video cameras. This invention relates to small edge drive type rotary variable resistors used in devices, especially in narrow spaces.

Configuration of conventional example and its problems Figures 1 and 2 are a side sectional view and a plan view of the main part of a conventional edge drive type rotary small variable resistor. In the figure, 1 is an insulating case made of molding material. On the inside thereof, a resistive element 2 having a resistive layer formed on the surface of a laminated plate is attached by the stud portions 5 and 6 of the terminals 3 and 4. A knob support stud 7 is attached to the center of the insulating case 1 via a terminal 8, and the large diameter portion 9 of the stud 7 also serves as a conductive ring. The support 10 of the knob support stud 7 holds a slider 11 and has a disc-shaped knob 13 having an anti-slip knurl 12 on the outer periphery.
is prevented from coming off by a washer 14 and is rotatably supported. When the knob 13 is rotated by pressing the outer knurled portion 12 of the knob 13 with a fingertip, the elastic contacts 15 and 16 of the slider 11 slide on the resistance element 2 and the large diameter portion 9 of the support stud 7, respectively. It rotates to change the resistance value between terminals 3 and 8 (or between terminals 4 and 8).

In this case, since the insulating case 1 and the resistance element 2 are constructed separately, the thickness is large, and the washer caulking portion 17 for preventing the knob 13, which is the upper and lower ends of the support stud 7, from coming off and for fixing it to the case 1 The caulking part 18 is the upper surface of the knob 13 and the case 1.
Because it comes out from the bottom of the variable resistor, the height of the variable resistor as a whole becomes large, and it has become too thick to be used in recent small consumer electronic devices.

OBJECTS OF THE INVENTION The present invention aims to solve the problems of the conventional products as described above and to realize an edge drive type rotary small variable resistor that is thinner.

Structure of the Invention In order to achieve this object, the present invention forms a resistor printed layer directly on the surface of a laminated board, and also attaches a large diameter part for preventing the knob from falling out and a caulked end part of the cylindrical stud for supporting the knob. This invention relates to the structure of an edge drive type rotary small variable resistor that is extremely thin by being accommodated within the thickness of the board and the thickness of the knob.

DESCRIPTION OF EMBODIMENTS FIGS. 3 to 5 show an embodiment of the rotary small variable resistor according to the present invention, in which FIG. 3 is a side sectional view, and FIGS. 4 and 5 are FIGS. A-A of
FIG. 3 is a sectional view in the direction and B-B. In the figure, 21 is a resistance substrate made of a laminated plate of phenol resin, etc., and a resistance printed layer 22 and a conductive band printed layer 23 are formed concentrically on the surface of the circular part.
The square part has electrode parts 24, 2 led out from both ends of the resistive printed layer 22 and the conductive band printed layer 23.
5, 26, external extraction terminals 27, 28, 29 are connected to the respective stud portions 30, 26 from the back side of the board 21.
It is worn by 31 and 32. Further, a circular hole 33 is provided in the center of the resistance board 21,
A circular constriction part 35 of a holding plate 34 made of a metal plate arranged on the back side of the board 21 is fitted here, and this holding plate 34 serves to reinforce the resistance board 21 and to electrically shield it. A protruding piece 37 for regulating the rotation angle of the knob 36 is provided on a part of the outer periphery. Further, the holding plate 34 may be provided with mounting feet 38 for mounting the variable resistor to the set's board, if necessary.

A disc-shaped knob 3 is made of synthetic resin and has a knurl 39 on its outer periphery to prevent slipping during operation.
6 holds a slider 40 on its inner surface, and is rotatably supported by a cylindrical step stud 42 passed through a two-step hole 41 at its center. This step stud 42 is set so that the large diameter part 43 for preventing the knob from coming off is accommodated within the outer large diameter part 44 of the two-stage knob hole 41, and the caulking part 45 is connected to the circular narrowing part 35 of the retaining plate 34.
It is fixed in the hole 46 of. Further, the height of the step rivet caulking tip portion 45 is set so as to fall within the drawing depth of the holding plate circular drawing portion 35.

The slider 40 held within the knob 36
The two sliding contacts 47 and 48 are set to be in sliding contact with the concentric printed resistive layer 22 and the printed conductive layer 23 on the resistive board 21, respectively, and are turned off by pressing the knurled portion 39 of the knob 36. 36 is rotated, the sliding contacts 47 and 48 connect to the resistive printed layer 22 and the conductive strip printed layer 2.
3 and short-circuit and slide between terminals 27 and 28 (or 2
8 and 29).

Further, a circular band-shaped portion 49 integrally formed near the outer periphery of the knob 36 lightly contacts near the outer periphery of the resistance board 21 to reduce vibration when the knob 36 is rotated, and also serves to reinforce the knob 36 and prevent dust from contacting the contact portion. It plays the role of

Effects of the Invention As described above, the present invention has two central holes provided in a disc-shaped knob through which a cylindrical step stud for supporting the knob is passed.
The large diameter part of the step rivet that prevents the knob from coming off should be placed within the plate thickness of the knob, and the depth of the narrowed part in the center of the holding plate, which will serve as the rivet seat for the step rivet, should be equal to or greater than the height of the step rivet's crimping part. As a result, one of the two ends of the stepped stud is housed in the two-stage hole in the knob, and the other end is housed in the narrowed part in the center of the retaining plate, so that it does not protrude from the knob or the retaining plate, making it possible to reduce the thickness of the small variable resistor. This greatly contributes to making the set used smaller and thinner.

Furthermore, since the number of parts used and the number of man-hours during assembly are smaller than in conventional products, there is also the effect of rationalization, and its practical value is high.

Furthermore, although the above embodiment describes the case of a single-acting variable resistor, as shown in FIG. 6 and FIG. For example, it is possible to configure two variable resistors within the same thickness, although the outer diameter is larger, which is very advantageous for small stereo type sets such as headphone stereos. It can also be achieved.

[Brief explanation of the drawing]

FIG. 1 is a side cross-sectional view of a conventional small rotary variable resistor, FIG. 2 is a plan view of a case configuring the variable resistor, and FIG. 3 is a small rotary variable resistor according to the present invention. FIG. 4 is a plan view of the substrate portion constituting the variable resistor, FIG. 5 is a plan view of the knob portion, and FIG. 6 is a side sectional view showing another embodiment of the present invention. A plan view of the base plate section, and FIG. 7 is a plan view of the knob section. 21...Resistance substrate, 22...Resistance printing layer, 33
... Circular hole, 34 ... Holding plate, 35 ... Circular narrowing part, 36 ... Disc-shaped knob, 37 ... Rotation angle regulating protrusion, 40 ... Slider, 41 ... Two-stage hole, 42...Cylindrical step stud, 43...Large diameter part for preventing the knob from coming off, 49...Circular band-shaped part.

Claims (1)

[Scope of Claims] 1. A concentric resistor printed layer is formed on the surface of a laminate whose outer shape is at least 1/2 or more circular, and a resistive substrate having a circular hole in the center and a resistive printed layer are rubbed on the resistive printed layer. a disc-shaped knob that holds a rotating slider and has a diameter slightly larger than the circular portion of the resistance board; a cylindrical step stud that rotatably supports the knob; and a holding plate having a circular constriction part in the center that fits into the circular hole of the resistance board and serves as a caulking seat for the step stud, and a retaining plate having a protrusion on the outer periphery for regulating the rotation angle of the knob, The center hole provided in the disc-shaped knob through which the cylindrical step stud for supporting the knob passes is a two-step hole, and the large diameter part of the step stud for preventing the knob from coming off is housed within the plate thickness of the knob, and the step stud is A small rotary variable resistor in which the depth of the narrowed part in the center of the holding plate, which serves as the caulking seat, is equal to or greater than the height of the caulking part of the step stud. 2. The rotary small variable resistor according to claim 1, characterized in that a circular band-shaped portion is integrally formed in a portion near the outer periphery of the knob, and is brought into light contact with a portion near the outer periphery of the resistor board surface. vessel.