JPH0329281B2 - - Google Patents

Description

[Detailed description of the invention] (1) Purpose of the invention Industrial application field The present invention is mainly used for small consumer electronic equipment such as audio equipment such as portable cassettes and radios, and video equipment such as micro televisions and videos. This invention relates to small variable resistors, especially edge drive type rotary variable resistors used in narrow spaces.

BACKGROUND ART FIGS. 4 and 5 are a side sectional view and a plan view of a main part of a conventional edge drive rotary variable resistor. In the figure, reference numeral 24 denotes an insulating case made of molded material, and inside thereof a resistance element 25 having a resistance layer formed on the surface of a laminated plate is attached by stud portions 28 and 29 of terminals 26 and 27, respectively. A knob support stud 30 is attached to the center of the insulating case 24 with a caulking portion 32 via a terminal. Near the center of the knob support stud 30, there is a large diameter portion 33 that also serves as a conductive ring. Further, a disk-shaped knob 37 that holds a slider 35 and has a non-slip knurl 36 on the outer periphery is prevented from coming off by a washer 38 and is rotatably supported on the support portion 34 of the knob support stud 30. There is. When the knurling 36 is pressed with a fingertip and the knob 37 is rotated, the elastic contacts 39 and 40 of the slider 35 are placed on the resistance element 25 and the large diameter portion 3 of the support stud 30, respectively.
3 to change the resistance value between the terminals 26 and 31 or between the terminals 27 and 31.

Problem to be Solved by the Invention The resistance element 25 is connected to the large diameter portion 33 of the support stud 30.
Since it needs to be larger in the radial direction than the diameter, the diameter becomes larger. In addition, since the insulating case 24 and the resistance element 25 are constructed separately, the thickness is large.
Since the upper end of the support stud 30 is fixed by the washer 38 for preventing the knob from coming off, the support stud 30 protrudes from the upper surface of the knob 37, increasing the height of the variable resistor as a whole. Therefore, they have become too large to be used in recent small consumer electronic devices.

The present invention aims to solve the problems of the conventional products as described above and to provide a more compact edge drive rotary variable resistor.

(2) Structure of the invention Means for solving the problems In order to solve the above conventional problems, the present invention provides the following:
A partially cutout annular resistive printing layer is formed on the surface.
and an insulating resistance substrate having a terminal led out from this resistance printed layer, and a three-stage hole in the center,
It has a rotatably operated knob with a knurl around its periphery, and a large diameter part for preventing the knob from coming off, the thickness of which is set so as to fit within the outer hole of the three-stage hole,
A step stud made of a conductive material is configured to rotatably support the knob on the resistor substrate, and a step stud is attached to the back surface of the resistor substrate so as to be electrically conductive with the step stud, and controls the rotation angle of the knob. , and a retaining plate having a terminal for external extraction, held in the knob so as to be located in the three-step hole, one end of which is in elastic contact with the inner surface of the large diameter portion of the step stud, and the other end of which is held in the three-step hole. A small variable resistor is made up of a rotary slider that comes into elastic contact with the resistor printed layer through a through hole provided in a part of the step hole to electrically short-circuit between them.

Function In the present invention, the terminals of the resistance board and the external terminals of the holding plate are electrically connected to each other by a rotating slider whose one end is in elastic contact with the inner surface of the large diameter part of the step stud, and whose other end is in elastic contact with the resistance printed layer. It is electrically conductive. When the knob is rotated, the rotary slider rotates accordingly and changes the contact position with the resistor printed layer, which changes the size of the resistor printed layer between the terminal of the resistor board and the external terminal of the holding plate. , which makes the resistance value variable. In addition, the thickness of the large diameter part of the step stud is set so that it fits within the outer hole of the three-step hole provided in the knob, so it does not protrude from the surface of the knob, and the rotating slider has a three-step hole. Since it is held in the knob so as to be located in the hole, a separate space for housing the rotary slider is not required, and the overall height can be reduced.

Embodiment FIGS. 1 to 3 show an embodiment of the present invention, in which FIG. 1 is a side sectional view, and FIGS. 2 and 3 are a BB direction and an A- A plan view opened in the A direction is shown.

In the figure, a partially cut-out annular resistive printed layer 2 is directly formed on the surface of an insulating resistive substrate 1 made of a laminate of phenolic resin, etc., and a partially cutout annular resistive printed layer 2 is formed outward from the resistive printed layer 2 on the rectangular portion. The electrode part 3 led out,
4 is formed. Reference numerals 5 and 6 denote external lead-out terminals, which are attached to the back surface of the board by studs 7 and 8, respectively.

On the other hand, a disc-shaped knob 10 made of synthetic resin and having a knurl 9 on its outer periphery to prevent slippage during operation is secured by a step stud 12 made of a cylindrical conductive material passed through a three-step hole 11 in the center. It is rotatably supported. The resistive printing layer 2 is formed in a part of the central three-stage hole 11.
A through hole 13 is provided at a position corresponding to . 1
Reference numeral 4 denotes a rotating slider, and the contact point 15 on the resistive printed layer side is configured to come into contact with the resistive printed layer 2 through the through hole 13 . The rotary slider 14 is held in the three-step hole 11, and has one end in elastic contact with the step stud 12 and the inner surface of the large diameter portion 16 for preventing the knob from coming off at a contact point 17, and the other end in elastic contact with the resistive printed layer 2. This is electrically short-circuited. The thickness of the large diameter part 16 of the step stud 12 is determined by the knob 1.
A holding plate 19 is set to fit inside the outer hole part 18 of the three-stage hole 11 of No. 0, and is arranged on the back surface of the resistance board 1.
It penetrates through the center hole 20 of the center hole 20 and is fixedly attached. The holding plate 19 is electrically connected to the stud 12, has an external terminal 22, and has a protrusion 23 for regulating the rotation angle of the knob in part.

In this configuration, when the knurl 9 is pushed and the knob 10 is rotated, the slider 14 held within the knob 10 rotates, and the two contacts 15, 1
7 slides on the surface of the resistive printed layer 2 and the large diameter portion 16 of the step stud 12 and connects between the terminals 5 and 22 or between the terminals 6 and 2.
By electrically shorting between the two, the resistance value can be changed.

(3) Effects of the invention The present invention has one end in elastic contact with the inner surface of the large diameter part of the step stud,
The rotary slider, whose other end is in elastic contact with the resistive printing layer, is held inside the knob so that it is located within the three-stage hole, so there is no need to create a space inside using a case like in conventional products. . In addition, the thickness of the large diameter part of the step stud for mounting the knob is set so that it fits within the outer hole of the three-step hole, so it does not protrude from the surface of the knob, and there is no vertical connection between the resistor board and the knob. Since it has a structure that can be divided, it can be made smaller, and it can greatly contribute to making the equipment used smaller and thinner.

Further, by making the small variable resistor of the present invention thinner, there is a margin in the dimensions of the mounting leg portion to the device, but by utilizing this portion, it is also possible to configure it as an auto dip.

Furthermore, since the number of parts used and the number of man-hours during assembly are smaller than in conventional products, it is also possible to streamline the manufacturing process.

[Brief explanation of drawings]

FIG. 1 is a side sectional view showing an embodiment of the present invention, FIG. 2 is a plan view taken along the line B-B in FIG. 1, and FIG. 3 is a plan view taken along the line A-A in FIG. 4 are side sectional views of the conventional example, and FIG. 5 is a plan view of the main parts of the conventional example. DESCRIPTION OF SYMBOLS 1... Resistance board, 2... Resistance printed layer, 3, 4... Electrode, 5, 6... Terminal, 10... Knob, 11... Three step hole, 12... Step stud, 13... Through hole, 14... Rotating slider, 16... Large diameter part, 18... Outer hole part, 19... Holding plate.

Claims (1)

[Claims] 1 An insulating resistance substrate with a partially cutout annular resistance print layer formed on the surface and a terminal led out from the resistance print layer, a three-stage hole in the center, and a knurled hole around the periphery. a knob that is rotatably operated, and a large diameter part for preventing the knob from coming off, the thickness of which is set so as to fit within the outer hole of the three-stage hole, and the knob is rotatably supported on the resistor board. a step stud made of a conductive material, and a holding plate attached to the back surface of the resistor board so as to be electrically connected to the step stud, regulating the rotation angle of the knob, and having a terminal for external extraction. is held in the knob so as to be located within the three-step hole, one end is in elastic contact with the inner surface of the large diameter part of the step stud, and the other end is inserted into the through hole provided in a part of the three-step hole. A small variable resistor comprising: a rotary slider that comes into elastic contact with the resistor printed layer via a rotating slider to electrically short-circuit between the slider and the resistor printed layer.