JP3236956B2 - Rotary 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 rotary variable resistor having a good heat radiation effect.

[0002]

2. Description of the Related Art Conventionally, there is a high power type rotary variable resistor which consumes a large amount of power. FIG. 5 is a perspective view showing an example of this type of power type rotary variable resistor. As shown in the figure, the rotary variable resistor 200 exposes a rotary operation part 203 of a sliding-type object housed from the center of an end face of a cap-shaped metal case 201, while the other end face of the metal case 201 is exposed. Three metal terminals 205 (only two are shown in the figure) project from the side.

The three metal terminals 205 are inserted into small holes provided in the hard printed circuit board 210, and are soldered to the circuit patterns 211 on the back surface thereof. Each circuit pattern 211 is pulled out to the vicinity of the lower end side of the hard printed circuit board 210, and the bar-shaped metal terminal 220 is soldered.

The reason why the rotary variable resistor 200 is mounted on the hard printed circuit board 210 is that three metal terminals 205 are mounted on other substrates or the like on which the rotary variable resistor 200 is to be mounted. Unlike the position of
This is because the position of the metal terminal 220 is provided.

[0005]

However, the above-mentioned prior art has the following problems. Since the rotary variable resistor 200, the hard printed circuit board 210, and the metal terminal 220 are separate components, the number of components is large, the number of soldering points is large, and the assembling work is complicated.

The rotary variable resistor 200 is of a high power type and generates a large amount of heat.
Heats up to about ° C. Therefore, a metal case 201 is used as the case, and this is used as a heat sink.
However, when the metal case 201 is used, the cost is increased as compared with the case where a resin is used.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has as its object to reduce the number of parts, facilitate assembly work, and achieve effective heat dissipation without using a metal case. Is to provide.

[0008]

Means for Solving the Problems To solve the above problems,
The present invention provides a case having a case body for housing a resistor, a sliding piece inserted into the case body, and a sliding piece housed in the case body so that a sliding contact thereof elastically contacts the resistor. And a slider electrically connected to the sliding piece in a housed state, a sliding member integrally attached to the slider, and a surface of the case on which the sliding member is installed. Comprises a terminal attached to the opposite surface and connected to the sliding piece and both ends of the resistor via a case, respectively, and further connected to the sliding piece and both ends of the resistor respectively. A contact piece is provided on a terminal connected to each connection piece, and the terminal is attached to a surface of the case such that the contact piece is bent to a side opposite to the surface of the case, and the contact piece is provided. Bending angle located near the hole provided in the case Is smaller than 90 ° with respect to the surface of the terminal, and furthermore, each of the connecting pieces at both ends of the resistor and the sliding piece provided on the other surface side of the case are made to penetrate through holes provided in the case. The connecting piece was elastically contacted with the surface of each contact piece to form a rotary variable resistor.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is an exploded perspective view of a power type rotary variable resistor according to an embodiment of the present invention.
As shown in FIG.
Of three terminals 70, 8
0, 90, while the case body 11 of the case 10
The sliding piece 30 and the resistor 40 are housed in the
0 is attached to the case body 11, and the shaft 63 of the
The holding plate 100 is fixed. Hereinafter, each component will be described.

The case 10 is formed by integrally molding a cylindrical case main body 11 having a bottom plate 13 and a rectangular terminal mounting plate portion 20 integrally mounted on the outer peripheral surface of the case main body 11 with synthetic resin. ing.

At the lower end portion inside the case body 11, a concave groove 15 extending in the thickness direction and guide grooves 17, 17 formed on both sides thereof are provided.

FIG. 2 shows the case 10 and the terminals 70, 8
It is the perspective view which looked at 0,90 from the opposite surface side. However, the case 10 is shown with the sliding piece 30 and the resistor 40 attached.

As shown in FIG.
A through-hole 19 is provided at the center of the slide 3, and a connection piece 33 of the slide piece 30 and connection pieces 45, 45 at both ends of the resistor 40, which will be described below, penetrate the upper and lower two places, respectively. Slits 21, 22, 23 are provided.

At the upper end of the case main body 11, a slit-shaped non-penetrating hole 25 for inserting a heat collecting portion 71 of a terminal 70 described below is provided.

On the other hand, a terminal 7 described below is
0, 80, and 90 through holes 2 into which the caulking protrusions 75 are inserted.
7 are provided.

Next, a sliding piece 30 shown in FIG. 1 forms a connecting piece 33 by projecting a tongue piece from an upper end of a sliding contact part 31 formed of a metal plate in a ring shape and bending it in an L-shape. Further, the tongue piece is made to protrude from the lower end of the sliding contact portion 31 so that the guide protrusion 35
Is formed.

Next, the resistor 40 is a winding resistor. That is, a resistance wire is wound around a flexible synthetic resin band-shaped core, and metal fittings 43 are attached to both ends thereof. The metal fittings 43, 43 are provided with tongue-shaped connecting pieces 45, 45 protruding in the direction of the case 10.

The slider 50 is made of a metal plate and has an arc-shaped arm 53 provided on the outer periphery of a ring-shaped base 51 and a sliding contact 55 provided at the center of the arm 53. The sliding contact 55 is formed so that its contact surface faces substantially directly upward by being bent toward the sliding mold 60 (see FIG. 3).

On the upper and lower sides of the inner periphery of the base 51, there are provided holding pieces 57, 57 which are bent toward the slide-type object 60, respectively.

The sliding object 60 is made of a synthetic resin, and is formed by projecting a shaft 63 from the center of a substantially disk-shaped rotating portion 61. The shaft 63 is provided with a step 65,
The holding pieces 57, 57 of the slider 50 are
Are provided with engagement grooves 67, 67 (only the upper one is shown in FIG. 1).

Next, as shown in FIGS. 1 and 2, the terminal 70 is formed by forming a plate-shaped hard and elongated metal plate into a substantially U-shape. A tongue-shaped heat collecting portion 71 is provided, and a tongue-shaped contact piece 73 is provided immediately below the heat collecting portion 71 in a direction opposite to the heat collecting portion 71. A cylindrical caulking projection 75 is provided so as to protrude toward the case 10 at each location.

As shown in FIGS. 1 and 2, the terminals 80 and 90 are provided with tongue-shaped contact pieces 83 and 93 which are bent to the opposite side of the case 10 at the upper end thereof, and are further provided with cylindrical members at two predetermined positions. The caulking projections 85 and 95 are provided so as to protrude toward the case 10.

Next, to assemble the rotary variable resistor, first, three terminals 70, 80, and 90 are attached to the case 10. At this time, each of the caulking protrusions 75, 85, and 95 is inserted into the through hole 27 of the case 10, and caulked and fixed on the surface on the opposite side of the case 10. At this time, the heat collecting portion 71 of the terminal 70
Is inserted into the hole 25 of the case 10.

Next, the sliding piece 30 and the resistor 40 are inserted into the case body 11. At this time, the guide projection 35 of the sliding piece 30 is inserted into the groove 15 and the metal fittings 4 at both ends of the resistor 40 are inserted.
3 and 43 are inserted into the guide grooves 17 and 17 and positioned respectively, and the connection piece 33 of the slide piece 30 and the resistor 40
Slit 2 provided with connecting pieces 45, 45 of bottom plate 13
1, 22, 23 (see FIG. 2).

As a result, as shown in FIG.
Contact piece 73 (83, 93) of each terminal 70 (80, 90)
Makes surface contact with each connecting piece 33 (45, 45).

At this time, since the bending angle θ of each contact piece 73 (83, 93) is set to θ <90 °, the contact with each connection piece 33 (45, 45) becomes an elastic contact, and the contact is more reliably achieved. A connection can be made.

Then, the connecting portions of the contact pieces 73 (83, 93) and the connection pieces 33 (45, 45) are soldered.

Next, the base 51 of the slider 50 is previously inserted into the shaft 63 of the sliding die 60, and the holding pieces 57, 57 are engaged with the engaging grooves 67, 67 to integrate them. The shaft 63 is inserted into the through hole 19 of the case body 11, and the pressing plate 100 is press-fitted into the tip of the shaft 63 protruding from the opposite surface so as not to come off.

FIG. 3 is a schematic sectional side view of the assembled rotary variable resistor. As shown in the figure, the sliding piece 30 and the slider 50 are electrically connected by being sandwiched between the step portion 65 of the shaft 63 and the bottom plate 13. The sliding contact 55 of the slider 50 is in elastic contact with the inner peripheral surface of the resistor 40.

When the sliding type object 60 is rotated, the slider 50 rotates integrally therewith, and the sliding contact 55 slides on the inner peripheral surface of the resistor 40, and the sliding member 50 Sliding piece 30
The resistance value between the terminal 70 electrically connected via the resistor 70 and the terminals 80 and 90 electrically connected to both ends of the resistor 40 is changed.

The rotary variable resistor uses a high-power type resistor as its resistor 40 and generates a large amount of heat, for example, generates heat at 150 ° C. to 160 ° C. at 2 W. Moreover, in order to reduce the cost of the material, the rotary variable resistor does not use metal as the case 10 and the sliding type object 60, but uses a synthetic resin having a poor heat dissipation.
However, in the present invention, since the heat collecting portion 71 made of a metal plate is disposed in parallel with the surface of the resistor 40 close to the center of the resistor 40 where the temperature is highest, the heat of the resistor 40 is reduced. The heat is transferred to the terminal 70 through the heat collecting portion 71 and is efficiently radiated into the air by its large surface area.

The heat at both ends of the resistor 40, which is not as high as at the center but is high, is also transmitted to the terminal 8 via the metal fittings 43, 43.
Heat is transferred to each of the first and second heat exchangers 0 and 90, and is radiated into the air.

In this embodiment, since the case main body 11 and the terminal mounting plate 20 constituting the case 10 are integrally molded from synthetic resin, the rotary variable resistor 200 as in the conventional example shown in FIG. And the rigid printed circuit board 210 need not be configured as separate components, and the number of components can be reduced and the assembling work can be facilitated.

In the above embodiment, the heat collecting portion 71 is arranged close to the center of the resistor 40, but the present invention is not limited to this, and the heat collecting portion 71 is arranged at another position close to the resistor 40. In short, any terminal may be used as long as a part of any of the terminals is arranged close to the vicinity of the heat generating portion of the resistor.

In the above embodiment, the winding resistor is used as the resistor 40. However, the present invention is not limited to the resistor having this structure, but can be applied to resistors having various other structures.

In the above embodiment, each terminal 70, 80, 90
Contact pieces 73, 83, 93 and connecting pieces 33, 45, 45
Are connected via the case 10, but the present invention is not applied only to the connection between these members,
The present invention can be applied to a portion connecting various other metal members via an insulating member. That is, a first metal member (sliding piece 30 or resistor 40) having a tongue-shaped connection piece and a second metal member (each terminal 70) having a contact piece bent in a substantially L-shape at a predetermined position. , 80, 90) can be applied to any portion as long as the first and second metal members are connected via an insulating member (case 10) for attaching the first and second metal members to both surfaces thereof.

[0037]

As described in detail above, the present invention has the following excellent effects. Since the terminal is made of a metal plate, the effect of the heat radiating plate is also used. Therefore, although the number of parts is small and assembly is easy, effective heat radiation can be achieved without using a metal case.

The connection between the two metal members via the insulating member can be easily and reliably performed.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a power type rotary variable resistor according to an embodiment of the present invention.

FIG. 2 is a perspective view of a case 10 and terminals 70, 80, 90 as viewed from opposite sides.

FIG. 3 is a schematic side sectional view of the assembled rotary variable resistor.

FIG. 4 shows each contact piece 73 (83, 93) and each connection piece 33;
It is a principal part expanded sectional view which shows the connection state with (45, 45).

FIG. 5 is a perspective view showing an example of a conventional power type rotary variable resistor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Case (insulating member) 21, 22, 23 Slit (hole) 30 Sliding piece 33 Connecting piece 40 Resistor (first metal member) 45, 45 Connecting piece 50 Slider 60 Sliding type 70, 80, 90 Terminal (second metal member) 71 Heat collector 73, 83, 93 Contact piece

──────────────────────────────────────────────────続 き Continued on the front page (56) References JP-A 1-1108902 (JP, U) JP-A 2-13703 (JP, U) JP-A 50-113836 (JP, U) JP-A 50-108 113837 (JP, U) Shokai Sho 57-154104 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01C 1/00-1/16 H01C 10/00-10/50

Claims (1)

(57) [Claims] 1. A case having a case main body for storing a resistor, a sliding piece inserted into the case main body, and a sliding contact housed in the case main body so as to elastically contact the resistor. A slider electrically connected to the sliding piece in a housed state, a sliding member integrally attached to the slider, and a surface of the case on which the sliding member is installed. Has a terminal attached to an opposite surface and connected to the sliding piece and both ends of the resistor via a case, respectively, and further connected to both ends of the sliding piece and the resistor respectively. A contact piece is provided on a terminal connected to each connection piece, and the terminal is attached to the surface of the case such that the contact piece is bent to the opposite side to the surface of the case, and the contact piece is Bend near the hole provided in the case The angle is made smaller than 90 ° with respect to the surface of the terminal, and furthermore, the sliding piece provided on the other surface side of the case and the connecting pieces at both ends of the resistor are passed through holes provided in the case. A rotary variable resistor, wherein each connecting piece is brought into elastic contact with the surface of each contact piece.