JPH03217001A - Variable resistor - Google Patents

Abstract

PURPOSE:To obtain a resistor whose minimum outer size can be made small by providing a structure wherein a tubular shaft is provided at the central part of a slider, a pivot is inserted into the tubular shaft, and one end surface of the tubular shaft is in contact with the surface of a substrate. CONSTITUTION:A slider 1 is rotatably provided on a substrate 10 on the surface of which a resistor 12 is provided. A contact part 4 of the slider 1 can be slid on the resistor 12. In this variable resistor, a tubular shaft 2a is provided at the central part of the slider 1. A pivot 7 is inserted into the tubular shaft 2a. One opening end surface 2d of the tubular shaft 2a is in contact with the surface of the substrate 10. For example, the upper end of the above described tubular shaft part 2a is made to be a junction part 2b which is expanding outward. A part of the junction part 2b is made to be a tongue piece 3 and made to extend in the outer direction. The junction part 4 is formed at the tip. A rotor 5 has a pivot 7 at the rear surface of a head part 6 having an adjusting groove 6a. The pivot 7 is inserted into the tubular shaft part 2a in the relation of shrink fit. The junction part 2b of the slider 1 is fixed to the rear surface of the head part 6 of the rotor 5.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a semi-fixed variable resistor that includes a substrate having a resistor on its surface, and on which a slider can slide.

Conventionally, variable resistors having structures shown in FIGS. 11 to 13 are known. FIG. 11 is a vertical sectional view of a three-terminal variable resistor, FIG. 12 is a plan view, and FIG. 13 is a plan view of a substrate used in this variable resistor. The variable resistor is composed of a slider 60, a rotor 65, and a substrate 70. The slider 60 is provided with a cylindrical shaft portion 61a at the center, and the upper end of the cylindrical shaft portion 61a is a joint portion 6lb that expands outward. A portion of the joint portion 6lb extends outward as a tongue piece 62, and has a contact portion 63 at its tip. The lower end of the cylindrical shaft portion 61a is separated by a flat portion 61c extending radially inward. A hole 64 into which the fulcrum shaft 67 of the rotor 65 is press-fitted is provided in the center of the flat portion 61c.

The rotor 65 includes a head 66 and a fulcrum shaft 67 provided on the back surface of the head 66. The fulcrum shaft 67 of the rotor 65 is inserted into the cylindrical shaft portion 61a of the slider 60, and the flat portion 6
It is press-fitted into the hole 64 of 1c. The substrate 70 has a resistor 72 and lead terminals 73, 74 formed on its surface by means such as printing. 75 are provided.

The resistor 72 provided on the surface of the substrate 70 has a substantially arc shape. The lead terminal 73 has an annular collector electrode portion 73g at one end, and this collector electrode portion 73a is formed on the outer periphery of the center hole 71 of the substrate 70. The rotor 65 to which the substrate 70 and the slider 60 are fixed, the fulcrum shaft 6 of the rotor 65
7 into the center hole 71 of the substrate 70, and the lower end 67a of the fulcrum shaft 67 is caulked to physically assemble it.

By the way, in this variable resistor, the minimum diameter Di (see FIG. 11) of the flat portion 61c at the lower end of the cylindrical shaft portion 618 provided at the center of the slider 60 is 1.4 to 1.8 mm. Ta. Furthermore, the minimum dimension of the gap di (see FIG. 11) between the cylindrical shaft portion 618 and the resistor 72 was 0.2 to 0.3 mm due to printing accuracy constraints. Further, the width Rl of the resistor 720 (see FIG. 13) is 0.4 to 0.6 mm.
was the limit. Therefore, the external dimensions 51 (
(see FIG. 13), if the gap between the outer periphery of the substrate 70 and the resistor 72 is C1=0.1 to 0.2 mm (see FIG. 13), then S=D1+2Xdl+2XR1+2XC1=2.8 to 4
．． 0 (mm), and the minimum external dimension of the variable resistor was limited to approximately 3 to 4 mm.

On the other hand, JP-A-1-110704, JP-A-1-1200
Variable resistors described in No. 05 and JP-A-1-120006 are also known, and in these variable resistors, the flat portion of the cylindrical shaft portion of the slider is formed to be slightly smaller.
Miniaturization remains an obstacle.

Therefore, an object of the present invention is to provide a variable resistor whose minimum external dimensions can be reduced.

Means and Function for Solving the Problems In order to solve the above problems, in the variable resistor according to the present invention, the slider has a cylindrical shaft in the center, and the fulcrum of the rotor or the lead terminal is attached to the cylindrical shaft. The shaft was inserted through the shaft, and one open end surface of the cylindrical shaft was in contact with the surface of the substrate. Therefore, the area occupied by one end of the cylindrical shaft provided at the center of the slider on the substrate surface is smaller than that of a conventional variable resistor in which one end of the cylindrical shaft has a flat portion extending radially inward or outward. becomes smaller compared to Furthermore, if the insertion fit between the cylindrical shaft and the fulcrum shaft is an intermediate fit or close fit, the area occupied by one end of the cylindrical shaft on the substrate surface becomes smaller.

Example Next, embodiments of the present invention will be described with reference to the accompanying drawings.

[First Embodiment] FIG. 1 is a vertical sectional view of a three-terminal variable resistor, FIG. 2 is a plan view, and FIG. 3 is a plan view of a substrate used in this variable resistor. This variable resistor includes a slider 1, a rotor 5 fixed to the slider 1, and a substrate 10 on which the slider 1 is in sliding contact.
It consists of

The slider 1 is made of a conductive metal plate such as stainless steel, and has a cylindrical shaft portion 2 at the center, and the upper end of the cylindrical shaft portion 2a is a joint portion 2b that extends outward. This cylindrical shaft portion 28 is formed by pressing such as drawing or burring.

A portion of the joint portion 2b extends outward as a tongue piece 3, and has a contact portion 4 at its tip. The lower end of the cylindrical shaft portion 2a has an open end surface 2d with a width approximately equal to the wall thickness of the side wall,
The conventionally formed flat portion is not provided.

The rotor 5 is made of a metal material such as copper, has an adjustment groove 68 for rotating the head 6 by applying a screwdriver, etc., and has a fulcrum shaft 7 on the back surface of the head 6. This fulcrum shaft 7 is inserted into the cylindrical shaft portion 2a with a tight fit. A joint 2b of the slider 1 is fixed to the back surface of the head 6 of the rotor 5, and fixes the slider 1 to the opening 5.

The substrate 10 has a resistor 12 and lead terminals 13 formed on its surface by means such as printing. 14. 1
5 is provided. The substrate 10 can be made of alumina, for example. The resistor 6 provided on the surface of the substrate 10 has a substantially arc shape, and is made of, for example, a cermet resistor material. At both ends of the resistor 6, one ends of lead terminals 14 and 15 are electrically connected. Lead terminal 13
has an annular collector electrode portion 138 at one end, and this collector electrode portion 13a is formed on the outer periphery of the center hole 11 of the substrate 10. Lead terminals 13, 14. The other end of the substrate 15 is formed from the side surface to the back surface side of the substrate 10 in order to form a chip type that can be surface mounted.

The rotor 5 to which the substrate 10 and the slider 1 are fixed is the rotor 5
Insert the fulcrum shaft 7 into the center hole 11 of the board 10, and
It is assembled integrally by caulking the lower end 7a of.

The variable resistor having the above configuration is rotatable around the fulcrum shaft 7 of the rotor 5, and at the same time, the contact portion 4 of the slider 1
slides on the resistor 12. The resistance values between the terminals 13 and 14 and between the terminals 13 and 15 are adjusted by the rotation angle of the slider 1. At this time, the open end surface 2d of the slider 1 is connected to the lead terminal 1.
The collector electrode 13a of No. 3 is pressed into contact with the collector electrode 13a of No. 3, thereby establishing an electrical connection between the two. Therefore, the width A of the collector electrode 13a should be sufficient to electrically connect the open end surface 2d at the lower end of the cylindrical shaft portion 2a. In this embodiment, the width is approximately the same as the thickness of the side wall of the cylindrical shaft portion 2a of the slider 1.

External dimension S (third dimension) of the variable resistor thus obtained
(see figure), the diameter of the open end surface 2d at the lower end of the cylindrical shaft 2a provided at the center of the slider 1 is D (see Fig. 1), and the gap between the cylindrical shaft 2a and the resistor 12 is D (see Fig. 1). d (see Figure 1), the width of the resistor 12 is R (see Figure 3), and the gap between the outer periphery of the substrate 10 and the resistor 12 is C (see Figure 3), then S = D + 2X d + 2X R+2X C=0.
8+2X0.2+2X0.4+2X0.1=2.2(m
m) becomes. That is, since there is no flat part at the lower end of the cylindrical shaft part 28, the diameter D of the open end surface 2d is 1.4 to 1.
Since it becomes about 0.8 mm from 8 mm (however, other values are the same as the conventional variable resistor), a variable resistor with a minimum external dimension of about 2 mm is obtained.

[Second Embodiment] FIG. 4 is a vertical sectional view of a three-terminal variable resistor, and FIG. 5 is a plan view. This variable resistor includes a slider 21, a rotor 25 fixed to the slider 21, and a substrate 30 on which the slider 21 is in sliding contact.

The slider 21 is provided with a cylindrical shaft portion 22a at the center, and the upper end of the cylindrical shaft portion 22a is a joint portion 22b. Joint part 22
A portion of b extends outward as a tongue piece 23, and has a contact portion 24 at its tip. The lower end of the cylindrical shaft portion 22a has an open end surface 22d with a width approximately equal to the wall thickness of the side wall.
have.

The rotor 25 has a cylindrical fulcrum shaft 2 formed by drawing a metal plate.
7 is formed, the portion corresponding to the head 26 is folded back to form two layers. The head 26 has an adjustment groove 26a for allowing rotation by applying a screwdriver or the like, and has a cylindrical fulcrum shaft 27 on the back surface of the head 26. This fulcrum shaft 27
is inserted into the cylindrical shaft portion 22a with an interference fit. The joint portion 22b of the slider 21 is fixed to the back surface of the head 26 of the rotor 25, thereby fixing the rotor 25 and the slider 21.

The substrate 30 has a resistor 32 and lead terminals 3 on its surface.
3. 34. 35, which basically have the same structure and function as the substrate 10 shown in the first embodiment.

The rotor 25 to which the substrate 30 and the slider 21 are fixed has the lower end 27a of the fulcrum shaft 27 of the rotor 25 aligned with the center hole 3 of the substrate 30.
1 and swaged together to assemble it as one piece.

The variable resistor having the above configuration is connected to the fulcrum shaft 2 of the rotor 25.
The contact portion 24 of the slider 21 slides on the resistor 32 at the same time. The resistance values between the terminals 33 and 34 and between the terminals 33 and 35 are adjusted by the rotation angle of the slider 21. At this time, the open end surface 22d of the slider 21
is pressed into contact with the collector electrode 33a of the lead terminal 33, thereby establishing an electrical connection between the two.

[Third Embodiment] FIG. 6 is a vertical sectional view of a three-terminal variable resistor, and FIG. 7 is a plan view. This variable resistor includes a slider 41, a rotor 45 fixed to the slider 41, and a substrate 50 on which the slider 41 is in sliding contact.

The slider 41 is provided with a cylindrical shaft portion 42a at the center, and the upper end of the cylindrical shaft portion 42a is a joint portion 42b. Joint part 42
A part of b extends outward as a tongue piece 43, and has a contact portion 44 at its tip. The lower end of the cylindrical shaft portion 428 has an open end surface 42d with a width approximately equal to the wall thickness of the side wall.

The rotor 45 has a circular hole 46b in the center, and an adjustment groove 46a on the top surface for rotating the rotor 45 by applying a screwdriver or the like. The joint portion 42b of the slider 41 is fixed to the back surface of the rotor 45, thereby fixing the rotor 45 and the slider 41.

The substrate 50 has a resistor 52 and lead terminals 5 on its surface.
3, 54. 55 are provided. A hole 51 is formed in the center of the substrate 50. The lead terminal 53 has a fulcrum shaft 53a, and the fulcrum shaft 538 is completely inserted into the hole 51 of the substrate 50 from the back side. Note that the resistor 52, lead terminal 54. 55 has the same configuration and functions as those shown in the first embodiment.

The rotor 45 to which the slider 41 is fixed is assembled by inserting the fulcrum shaft 53 of the lead terminal 53 through the cylindrical shaft portion 42a of the slider 41 and the circular hole 46b of the rotor 45, and caulking the upper end portion 53b. It is assembled so as to be rotatable around the fulcrum shaft 53a.

In the variable resistor having the above configuration, the rotor 45 is rotatable about the fulcrum shaft 53a, and at the same time the contact portion 44 of the slider 41 slides on the resistor 52. Also,
Electrical connection between the slider 41 and the lead terminal 53 is achieved by contact between the cylindrical shaft portion 42a and the fulcrum shaft 53a. Terminal 53 at the rotation angle of slider 41
-54 and the resistance value between terminals 53-55 is adjusted.

At this time, the open end surface 42d of the lower end of the cylindrical shaft portion 42a of the slider 41 is pressed against the outer periphery of the hole 51 of the substrate 50.

[Fourth Embodiment] FIG. 8 is a plan view of a three-terminal variable resistor, FIG. 9 is a vertical sectional view, and FIG. 10 is a bottom view. This variable resistor is
Slider 81 and rotor 8 integrally formed with slider 81
5. Consists of a substrate 90 on which the slider 81 is in sliding contact.

The slider 81 has a cylindrical shaft portion 82 at the center, and the cylindrical shaft portion 8
A part of the upper end of 2 is extended, and the rotor 8 is folded back.
5 is formed. In addition, the other part of the upper end of the cylindrical shaft part 82 extends outward as a tongue piece 83, and has a contact part 84 at its tip. The lower end of the cylindrical shaft portion 82 has an open end surface 82d with a width approximately equal to the thickness of the side wall.

The rotor 85 has a circular hole 86 for caulking work in the center and an adjustment groove 87 that overlaps this hole 86.

12 - The substrate 90 has a resistor 92 and lead terminals 9 on its surface.
3. 94. 95 is provided. A hole 91 is formed in the center of the substrate 90. The lead terminal 93 has a fulcrum shaft 93a, and this fulcrum shaft 938 is inserted into the hole 91 of the substrate 90 from the back side. Note that the resistor 92, lead terminal 94. Reference numeral 95 has the same configuration and functions as those shown in the first embodiment.

The rotor 95, which is integrally formed with the slider 81, is inserted into the fulcrum shaft 93a of the lead terminal 93 by inserting the cylindrical shaft portion 82 of the slider 81 into the fulcrum shaft 93a and caulking the upper end portion 93b.
It is assembled so that it can rotate around a.

In the variable resistor having the above configuration, the rotor 85 is rotatable about the fulcrum shaft 93a, and at the same time the contact portion 84 of the slider 81 slides on the resistor 92. Also,
Electrical connection between the slider 81 and the lead terminal 93 is achieved by contact between the cylindrical shaft portion 82 and the fulcrum shaft 93a. Between the terminals 9394 and 93 at the rotation angle of the slider 81
The resistance value between -95 is adjusted. At this time, the slider 81
The open end surface 82d of the lower end of the cylindrical shaft portion 82 is connected to the hole 9 of the substrate 90.
It is pressed against the outer periphery of 1.

Although the variable resistor according to the present invention has been described in detail above, the present invention is not limited to the above embodiments.
Changes may be made within the scope of the gist.

For example, the present invention is applicable not only to chip-type variable resistors but also to discrete-type variable resistors.

Effects of the Invention As is clear from the above explanation, the present invention has a structure in which one open end surface of the cylindrical shaft of the slider is in contact with the substrate surface, so that the area occupied by one end of the cylindrical shaft on the substrate surface is reduced. is smaller compared to the conventional structure in which one end of the cylindrical shaft has a flat part extending radially inward or outward, making it possible to obtain a variable resistor with small external dimensions, making it suitable for VTR cameras and This makes it possible to respond to miniaturization of electronic still cameras, etc.

Furthermore, if the insertion fit between the cylindrical shaft and the fulcrum shaft is an intermediate fit or tight fit, the area occupied by one end of the cylindrical shaft on the board surface will be smaller, so the outer shape will be better. A variable resistor with small dimensions can be obtained.

[Brief explanation of drawings]

1 to 3 show a first embodiment of the variable resistor according to the present invention, in which FIG. 1 is a vertical sectional view, FIG. 2 is a plan view, and FIG. 3 is used in this variable resistor. FIG. 3 is a plan view of a removable substrate. 4 and 5 show a second embodiment of the variable resistor according to the present invention, with FIG. 4 being a vertical sectional view and FIG. 5 being a plan view. 6 and 7 show a third embodiment of a variable resistor according to the present invention, with FIG. 6 being a vertical sectional view and FIG. 7 being a plan view. 8 to 10 show a fourth embodiment of the variable resistor according to the present invention, in which FIG. 8 is a plan view, FIG. 9 is a vertical sectional view, and FIG. 10 is a bottom view. 11 to 13 show a conventional example, in which FIG. 11 is a vertical sectional view, FIG. 12 is a plan view, and FIG. 13 is a plan view of a substrate that can be used for a variable resistor. DESCRIPTION OF SYMBOLS 1... Slider, 28... Cylindrical shaft part, 2d... Open end surface, 5... Rotor, 7... Fulcrum shaft, 10... Substrate, 21... Slider , 22a... cylindrical shaft portion, 22d
... open end surface, 25 ... rotor, 27 ... fulcrum shaft, 30 ... substrate, 41 ... slider, 42a ... cylindrical shaft portion, 42d ... open end surface, 45 ...Rotor, 5
0... Substrate, 53a... Fulcrum shaft, 81... Slider, 82... Cylindrical shaft portion, 82d... Open end surface, 85...
... Rotor, 90... Board, 93a... Fulcrum shaft.

Claims (2)

[Claims] 1. A variable resistor in which a slider is rotatably provided on a substrate having a resistor on its surface, and a contact portion of the slider can slide on the resistor, wherein the slider has a cylinder in the center. 1. A variable resistor characterized in that a variable resistor is provided with a cylindrical shaft, a fulcrum shaft is inserted through the cylindrical shaft, and one open end surface of the cylindrical shaft is in contact with the surface of the substrate. 2. 2. The variable resistor according to claim 1, wherein the insertion fit between the cylindrical shaft and the fulcrum shaft is an intermediate fit or an interference fit.