JP2004311665A - Rheostat - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rheostat which can prevent the turnover of a driver plate from occurring, having possibility of occurrence when the tip of a driver is inserted into the engaging hole of the driver plate and rotated. <P>SOLUTION: The rheostat includes an insulating substrate 1 in which terminals 3, 4 each made of metal are integrally insert molded, and a slidable contact 6 made of metal attached to the terminal 4 by caulking. The part 11 of the folding part side of the driver plate 6a of the slidable contact 6 is partially blanked in which the driver plate 6a and a plate-like part 6c are superposed. The part 12 of the rear surface of the driver plate 6a is work hardened by recessing the driver plate 6a by crushing working. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a variable resistor used for various electronic devices and the like.
[0002]
[Prior art]
As this type of variable resistor, for example, the one described in Patent Document 1 is known. As shown in FIGS. 16 and 17, the variable resistor disclosed in Patent Document 1 includes an insulating substrate 51 having a substantially arc-shaped resistor 58 provided on the surface thereof, and a sliding contact 56 rotatably attached to the insulating substrate 51. And Metal terminals 52 and 53 are insert-molded on the insulating substrate 51.
[0003]
The sliding contact 56 has a driver plate 56b that is rotated by a tool such as a driver, and a main body that is folded from the outer edge of the driver plate 56b to the back side. The main body includes a contact arm 56a that slides on the resistor 58 and a dish 56c that supports the contact arm 56a. The sliding contact 56 is rotatably attached to the insulating substrate 51 by being caulked by the dish-shaped portion 56c. At the center of the driver plate 56b, a cross-shaped engaging hole 56d that is rotated by a tool such as a driver is formed.
[0004]
Further, as a device using a ceramic substrate as an insulating substrate, for example, a variable resistor described in Patent Document 2 is known.
[0005]
[Patent Document 1]
JP 2001-15308 A [Patent Document 2]
JP 2002-231512 A
[Problems to be solved by the invention]
By the way, when adjusting the resistance value of the variable resistor of Patent Document 1 or Patent Document 2, as shown in FIG. 17, the tip of the driver 60 is inserted obliquely into the engagement hole 56d of the driver plate 56b. May be rotated. Then, the tip of the driver 60 may enter the gap between the driver plate 56b and the dish-shaped portion 56c in the portion indicated by the circle A in FIG. When the driver 60 is further rotated in this state, as shown in FIG. 17, the driver plate 56b is turned up in the direction of arrow K by the principle of leverage with the bent portion (the portion indicated by the circle B) as a fulcrum. The problem of going up occurs.
[0007]
Therefore, an object of the present invention is to provide a variable resistor that can prevent the driver plate from being turned upside-down, which may occur when the tip of the driver is inserted into the engagement hole of the driver plate and rotated. It is in.
[0008]
Means and action for solving the problem
In order to achieve the above object, a variable resistor according to the present invention comprises:
(A) an insulating substrate provided with a substantially arc-shaped resistor on its surface;
(B) a sliding contact rotatably attached to the insulating substrate,
(C) the sliding contactor has a driver plate and a main body formed by bending and overlapping one metal plate;
(D) the main body is composed of a contact arm portion that slides on the resistor, and a dish-shaped portion that supports the contact arm portion;
(E) that the part where the dish-shaped part and the driver plate rotated by the tool are overlapped is half-punched;
It is characterized by.
[0009]
Alternatively, in a portion where the dish-shaped portion and the driver plate rotated by the tool overlap each other, the protrusion provided on one of the dish-shaped portion and the driver plate is fitted into the fitting hole provided on the other. It is characterized by having.
[0010]
Alternatively, the overlapping portion of the dish-shaped portion and the driver plate rotated by the tool is burring-processed.
[0011]
With the above configuration, the half-punched part, the part where the convex part fits into the fitting hole, and the burring part are caulked between the dish-shaped part and the driver plate, so that the driver plate turning around the bent part occurs. It becomes difficult to do. When half-punching is performed, by setting the punching amount of the half-punched portion larger than the punching amount, the half-punched piece bulges in a direction perpendicular to the thickness thereof and squeezes. Thereby, the swaging strength of the half-punched portion is further increased.
[0012]
Further, the variable resistor according to the present invention is characterized in that at least a part of the driver plate is work-hardened. Since the work hardened portion enhances the mechanical strength of the driver plate, the driver plate is less likely to be turned around the midpoint of the driver plate as a fulcrum. Further, it is preferable that the work hardened portion includes a portion in which the distance between the outer edge of the driver plate and the tool engagement hole provided substantially in the center of the driver plate is minimized.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of a variable resistor according to the present invention will be described with reference to the accompanying drawings.
[0014]
[First Embodiment, FIGS. 1 to 9]
FIGS. 1, 2 and 3 are an external perspective view, a plan view and a side view of the variable resistor, respectively. The variable resistor includes an insulating substrate 1 in which metal fixed-side terminals 2 and 3 and a variable-side terminal 4 are integrally insert-molded, and a metal sliding contact 6 attached to the variable-side terminal 4 by caulking. It is composed of
[0015]
The insulating substrate 1 is obtained by insert-molding the fixed terminals 2 and 3 and the variable terminal 4 attached to the hoop material 10 shown in FIG. 4 with a resin as shown in FIG. It is formed. As a resin material, a heat-resistant thermoplastic resin or a thermosetting resin is used in order to withstand the heat of soldering and to enable stable operation in a high-temperature atmosphere. For example, liquid crystal (LCP) resin, modified 6T nylon, polyphenylene sulfide (PPS) resin, polyester resin, epoxy resin, diallyl phthalate resin and the like are used.
[0016]
The conducting portions 2a and 3a of the fixed terminals 2 and 3 are exposed on the upper surface of the insulating substrate 1. External connection portions 2b, 3b, 4b, which are portions for soldering the fixed-side terminals 2, 3 and the variable-side terminal 4 to the printed board, are drawn out from the bottom surface of the board 1 and upward along the side face of the board 1. It is bent. On the upper surface of the substrate 1, a resistor 5 (see FIG. 8) made of carbon or the like is applied in a substantially arc shape so as to cover the conductive portions 2a and 3a of the fixed terminals 2 and 3, and is formed by drying. . As a result, the fixed terminals 2 and 3 are electrically connected to the resistor 5.
[0017]
A cylindrical eyelet 4 a is integrally formed at one end of the variable terminal 4, and the eyelet 4 a is exposed from the central hole 1 a of the substrate 1. The fixed-side terminals 2 and 3 and the variable-side terminal 4 are made of a thin plate of good conductivity such as copper alloy or non-rusted steel. In order to improve the solder wettability, at least the external connection portions 2b, 3b and 4b have gold and silver. Surface treatment such as noble metal plating, solder plating, tin plating, or the like.
[0018]
As shown in FIG. 6, the sliding contact 6 includes a driver plate 6a which is an annular upper surface, a dish-shaped portion 6c which is folded from the outer edge of the driver plate 6a to the back side along a dotted line L, and a dish-shaped portion. 6c has a semicircular contact arm 6d formed on the outer peripheral edge opposite to the folded portion. The sliding contact 6 is formed by stamping and drawing a single metal plate with a press.
[0019]
A cross-shaped engagement hole (adjustment hole) 6b that is rotated by a tool such as a driver is formed in the center of the driver plate 6a. The portion near the engagement hole 6b on the back surface of the driver plate 6a (including the portion where the distance between the outer edge of the driver plate 6a and the engagement hole 6b is the smallest) 12 is formed by crushing the driver plate 6a by crushing. Work hardened.
[0020]
Further, at the outer peripheral edge of the back surface of the driver plate 6a opposite to the bent portion, in other words, at the portion of the dish-shaped portion 6c that is folded toward the back surface of the driver plate 6a, facing the contact portion 6f of the contact arm portion 6d, A step 6e is provided so as to increase the distance between the driver plate 6a and the contact arm 6d.
[0021]
The contact arm 6d has a spring property and has a convex contact 6f at the center. The contact portion 6f elastically contacts and slides on the resistor 5 of the substrate 1.
[0022]
The portion 11 on the bent portion side of the driver plate 6a, where the driver plate 6a and the dish-shaped portion 6c overlap, is subjected to half punching. This half-punching is performed using a press device as shown in FIG. That is, after the folded sliding contact 6 is set in the female mold 82 having the concave portion 82a having the predetermined depth dimension T2, the male mold 81 having the convex portion 81a having a cross section substantially equal to the concave portion 82a is lowered. Then, the driver plate 6a and the dish-shaped portion 6c are simultaneously half-opened.
[0023]
At this time, it is preferable that the driving amount dimension T1 of the convex portion 81a is larger than the depth size (in other words, the driving amount size) T2 of the concave portion 82a. This is because the half blanked piece expands and swells in a direction perpendicular to the thickness direction, and the crimping strength of the half blanked portion 11 is further increased.
[0024]
As shown in FIGS. 8 and 9, a fitting hole 6 g that fits into the eyelet portion 4 a of the variable terminal 4 is formed in the center of the dish-shaped portion 6 c, and the fitting hole 6 g is connected to the variable terminal 4. After the eyelet 4a is fitted to the eyelet 4a, the eyelet 4a is caulked so as to open outward, so that the sliding contact 6 is rotatably attached to the substrate 1.
[0025]
The sliding contact 6 is made of a metal having good conductivity and spring characteristics. For example, a thin plate made of a copper alloy, non-rust steel, or a precious metal alloy is used.
[0026]
To change the resistance value of the variable resistor, for example, the tip of a Phillips screwdriver is inserted into the engagement hole 6b, and the sliding contact 6 is turned. Thereby, the resistance value between the fixed terminal 2 (or 3) and the variable terminal 4 is changed.
[0027]
As shown in FIG. 3, the variable resistor thus obtained has the half-punched portion 11 on the bent portion side of the driver plate 6a, so that the mechanical strength of the overlapping structure of the driver plate 6a and the dish-shaped portion 6c is provided. Will be higher. Therefore, even when the tip of the driver is inserted obliquely into the engagement hole 6b of the driver plate 6a and rotated, the driver plate 6a with the bent portion as a fulcrum is not turned up.
[0028]
Further, since the half-punched portion 11 is located on the bent portion side of the driver plate 6a, the driver using only the half-punched portion 11 as a fulcrum with the middle portion of the driver plate 6a (the portion where the bent portion is removed) is provided. There is a concern that the plate 6a may be turned up. Therefore, in order to prevent this, in the first embodiment, a work hardened portion 12 is provided on the back surface of the driver plate 6a to increase the mechanical strength of the driver plate 6a.
[0029]
As a result, the operability at the time of adjusting the resistance value with a tool such as a driver can be improved. These half-punching and work hardening can be performed simultaneously with the pressing of the sliding contact 6, and the manufacturing cost is low.
[0030]
Further, since the step 6e increases the distance T4 between the driver plate 6a and the contact arm 6d, even if the height of the dish 6c is reduced to reduce the height, the height of the contact arm 6d is reduced. The contact portion 6f is less likely to contact the driver plate 6a. Therefore, it is possible to avoid contact between the driver plate 6a and the contact arm 6d due to a manufacturing error of the sliding contact 6 and the insulating substrate 1. As a result, the pressure at which the contact portion 6f of the contact arm portion 6d contacts the resistor 5 is stabilized, and variations in electrical characteristics (change in resistance value) can be suppressed.
[0031]
When the step 6e is formed by coining or the like, the strength of the driver plate 6a is improved by work hardening. The depth dimension T3 of the step 6e is set so that the driver plate 6a and the contact arm 6d do not theoretically come into contact with each other in consideration of a tolerance of a dimension related to the height direction of the slide contact 6 and the substrate 1.
[0032]
For example, in the case of the first embodiment, the thickness dimension of the insulating substrate 1 is set to 0 in a variable resistor having an outer dimension of 2.7 mm in length, 2.1 mm in width, and 0.8 ± 0.05 mm in height. 0.5 (+ 0.03 / -0.05) mm, the thickness of the metal plate of the sliding contact 6 is 0.1 mm, the distance between the upper surface of the insulating substrate 1 and the sliding contact 6 is 0.1 mm, Is set to 0.02 mm, the driving dimension T1 of the half-punched portion 11 is set to 0.05 mm, which is about half the thickness of the metal plate forming the sliding contact 6, and the driving dimension T2 is set to 0.04 mm. The crushing depth of the work hardened portion 12 is 0.03 mm, the depth T3 of the step 6e is 0.03 mm, and the interval T4 between the driver plate 6a and the contact arm 6d at the contact 6f is 0. 0.08 mm.
[0033]
[Second embodiment, FIG. 10]
FIG. 10 is an exploded perspective view of the variable resistor according to the second embodiment. The variable resistor includes an insulating substrate 31 made of ceramic, a variable terminal 20 made of metal, and a metal sliding contact 6 attached to the variable terminal 20 by caulking. The sliding contact 6 is the same as that described in the first embodiment, and a detailed description thereof will be omitted.
[0034]
The insulating substrate 31 is obtained by forming a ceramic material such as alumina, and then firing. On the upper surface of the substrate 31, a resistor 35 made of cermet or the like is formed in a substantially arc shape centered on the central hole 31a and baked. External electrodes 32 and 33 formed from the side surface to the back surface of the substrate 31 are connected to both ends of the resistor 35. The external electrodes 32 and 33 are formed by a method such as printing, sputtering, or vapor deposition.
[0035]
The slide contact 6 fits the eyelet portion 21 of the variable terminal 20 inserted into the center hole 31a of the insulating substrate 31 into a fitting hole 6g formed in the center of the dish-shaped portion 6c. By caulking the portion 21 to open outward, the portion 21 is rotatably attached to the insulating substrate 31. The variable terminal 20 is attached to the bottom surface of the insulating substrate 31. At one end of the variable side terminal 20, a stopper 22 bent upward along the side surface of the insulating substrate 31 is formed.
[0036]
The variable resistor having the above configuration has the same operation and effect as the variable resistor of the first embodiment.
[0037]
[Third Embodiment, FIGS. 11 and 12]
FIG. 11 is a developed side view of a sliding contact 6A used in the variable resistor according to the third embodiment. The sliding contact 6A is substantially the same as the sliding contact 6 described in the first embodiment. However, a convex portion 6h is formed in advance on the bent portion side of the driver plate 6a and in a portion where the driver plate 6a and the dish-shaped portion 6c overlap with each other, at a position opposed to the convex portion 6h of the dish-shaped portion 6c. The fitting hole 6i is formed in advance.
[0038]
The sliding contact 6A is folded at the position indicated by the dotted line L, and as shown in FIG. 12, the protruding portion 6h is fitted into the fitting hole 6i and engaged with each other, whereby the dish-shaped portion 6c and the driver plate 6a are caulked.
[0039]
Since the variable resistor provided with the sliding contact 6A having such a structure has the fitting portion between the convex portion 6h and the fitting hole 6i on the bent portion side of the driver plate 6a, the driver plate 6a and the plate-like portion 6c are provided. The mechanical strength of the overlapping structure increases. Therefore, even when the tip of the driver is inserted obliquely into the engagement hole 6b of the driver plate 6a and rotated, the driver plate 6a with the bent portion as a fulcrum is not turned up.
[0040]
[Fourth embodiment, FIGS. 13 to 15]
FIG. 13 is a side view of a sliding contact 6B used in the variable resistor according to the fourth embodiment. The sliding contact 6B is substantially the same as the sliding contact 6 described in the first embodiment. However, a pilot hole 6k is formed in advance on the bent portion side of the driver plate 6a and in a portion where the driver plate 6a and the plate-like portion 6c overlap, and the plate-like portion 6c is located at a position facing the pilot hole 6k. The fitting hole 6j is formed in advance.
[0041]
The sliding contact 6B in which the driver plate 6a and the dish-shaped portion 6c are folded is subjected to burring using a press device as shown in FIG. That is, the punch 91 is lowered to aim at the prepared hole 6k of the slide contact 6B set on the support table 92 of the press device, and the prepared hole 6k is pushed and expanded by the punch 91 to form a flange. As a result, a cylindrical projection 61 is formed on the driver plate 6a. The cylindrical projection 6l caulks the hole wall of the fitting hole 6j of the dish-shaped portion 6c in the direction of arrow K. Thus, a sliding contact 6B as shown in FIG. 15 is obtained. The prepared hole 6k is not necessarily required to be formed.
[0042]
Since the variable resistor provided with the sliding contact 6B having such a structure has a burring portion on the bent portion side of the driver plate 6a, the mechanical strength of the overlapping structure of the driver plate 6a and the dish-shaped portion 6c is reduced. Get higher. Therefore, even when the tip of the driver is inserted obliquely into the engagement hole 6b of the driver plate 6a and rotated, the driver plate 6a with the bent portion as a fulcrum is not turned up.
[0043]
[Other embodiments]
It should be noted that the present invention is not limited to the above embodiment, and can be variously modified within the scope of the gist. For example, the shape, position, and number of the part where the half-punched part 11 and the convex part 6h of the driver plate 6a are fitted into the fitting holes 6i and the burring processing part can be variously deformed within a range where caulking can be performed. The same applies to the shape, position and number of the work hardened portions 12.
[0044]
Further, in the above embodiment, the step 6e and the work hardened portion 12 are provided on the same surface (back surface) of the driver plate 6a in order to form the work hardened portion 12 at the same time, but the work hardened portion 12 is provided on the front surface of the driver plate 6a. It may be something.
[0045]
【The invention's effect】
As apparent from the above description, according to the present invention, since the half-punched portion, the portion where the convex portion is fitted into the fitting hole, and the burring portion caulk the dish-shaped portion and the driver plate, the bent portion is supported by the fulcrum. This makes it difficult for the driver plate to be turned over. In the case of half-punching, by setting the amount of punching in the half-punched portion larger than the amount of punching, the half-punched piece expands in the direction perpendicular to its thickness and squeezes. Thereby, the swaging strength of the half-punched portion can be further increased.
[0046]
In addition, since a mechanically hardened portion is provided on the driver plate to increase the mechanical strength of the driver plate, it is possible to prevent the driver plate from being turned up at the midpoint of the driver plate (the portion where the bent portion is removed). it can. As a result, the operability at the time of adjusting the resistance value with a tool such as a driver can be improved.
[Brief description of the drawings]
FIG. 1 is an external perspective view showing a first embodiment of a variable resistor according to the present invention.
FIG. 2 is a plan view of the variable resistor shown in FIG.
FIG. 3 is a partial sectional side view of the variable resistor shown in FIG. 1;
FIG. 4 is an exemplary perspective view showing one example of a procedure for manufacturing the insulating substrate shown in FIG. 1;
FIG. 5 is a perspective view showing a manufacturing procedure following FIG. 4;
FIG. 6 is an exploded plan view of the sliding contact shown in FIG. 1;
FIG. 7 is a sectional view showing an example of a procedure for forming a half-punched portion of the driver plate.
FIG. 8 is an assembled perspective view of the variable resistor shown in FIG. 1;
FIG. 9 is a sectional view taken along line IX-IX of FIG. 8;
FIG. 10 is an assembled perspective view showing a second embodiment of the variable resistor according to the present invention.
FIG. 11 is an exploded partial cross-sectional side view of a sliding contact used in a third embodiment of the variable resistor according to the present invention.
FIG. 12 is an exploded partial cross-sectional side view showing a manufacturing procedure of the slide contact following FIG. 11;
FIG. 13 is a partial cross-sectional side view of a sliding contact used in a fourth embodiment of the variable resistor according to the present invention.
FIG. 14 is an enlarged cross-sectional view showing a manufacturing procedure of the slide contact following FIG. 13;
FIG. 15 is a partial cross-sectional side view of a sliding contact used in the fourth embodiment.
FIG. 16 is a plan view showing a conventional variable resistor.
FIG. 17 is a side view showing a conventional variable resistor.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Insulating board 6, 6A, 6B ... Sliding contact 6a ... Driver plate 6b ... Engagement hole 6c ... Dish-like part 6d ... Contact arm part 6h ... Convex part 6i ... Fitting hole 6l ... Cylindrical protrusion part 6j ... Fitting hole 11: Semi-punched part 12: Work hardened part T1: Driving amount dimension T2: Driving amount dimension

Claims (9)

An insulating substrate provided with a substantially arc-shaped resistor on its surface,
A sliding contact rotatably attached to the insulating substrate,
The sliding contactor has a driver plate and a main body configured by bending and overlapping one metal plate,
The main body includes a contact arm portion that slides on the resistor, and a dish-shaped portion that supports the contact arm portion,
A portion where the dish-shaped portion and the driver plate rotated by a tool are overlapped is half-punched,
A variable resistor characterized by the following. 2. The variable resistor according to claim 1, wherein the half-punched portion is formed so that a driving amount is larger than a driving amount. 3. An insulating substrate provided with a substantially arc-shaped resistor on its surface,
A sliding contact rotatably attached to the insulating substrate,
The sliding contactor has a driver plate and a main body configured by bending and overlapping one metal plate,
The main body includes a contact arm portion that slides on the resistor, and a dish-shaped portion that supports the contact arm portion,
At least a part of the driver plate rotated by a tool is work-hardened,
A variable resistor characterized by the following. The said work hardening part contains the part which the space | interval of the outer periphery edge of the said driver plate and the tool engagement hole provided in the substantially center part of the driver plate becomes the smallest. Variable resistor. The variable resistor according to claim 3 or 4, wherein a portion where the dish-shaped portion and the driver plate overlap is half-punched. An insulating substrate provided with a substantially arc-shaped resistor on its surface,
A sliding contact rotatably attached to the insulating substrate,
The sliding contactor has a driver plate and a main body configured by bending and overlapping one metal plate,
The main body includes a contact arm portion that slides on the resistor, and a dish-shaped portion that supports the contact arm portion,
In a portion where the dish-shaped portion and the driver plate rotated by a tool are overlapped, a protrusion provided on one of the dish-shaped portion and the driver plate is fitted into a fitting hole provided on the other. is being done,
A variable resistor characterized by the following. The variable resistor according to claim 6, wherein at least a part of the driver plate rotated by a tool is work-hardened. An insulating substrate provided with a substantially arc-shaped resistor on its surface,
A sliding contact rotatably attached to the insulating substrate,
The sliding contactor has a driver plate and a main body configured by bending and overlapping one metal plate,
The main body includes a contact arm portion that slides on the resistor, and a dish-shaped portion that supports the contact arm portion,
A portion where the dish-shaped portion and the driver plate rotated by a tool are overlapped is burring-processed,
A variable resistor characterized by the following. 9. The variable resistor according to claim 8, wherein at least a part of the driver plate rotated by a tool is work-hardened.

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