JP4667946B2 - Variable resistor - Google Patents

Description

  The present invention relates to a structure of a variable resistor that is used in an audio device or the like and that is rotated by an operation knob to adjust a volume or the like.

  As a conventional variable resistor structure, a rotating body having a conductive slider is made to face an insulating substrate on which a resistor and the like held in a housing are formed, and the rotating body is rotated in accordance with the rotation operation of the operation shaft. There is known a configuration in which a change in resistance value is detected by rotating the slider and bringing the slider and the resistor into sliding contact with each other (see, for example, Patent Document 1).

The structure of this conventional variable resistor is shown in FIG. FIG. 9 is a cross-sectional view showing a conventional variable resistor.
In the figure, the bearing 51 is formed by integrally forming a substantially cylindrical shape by zinc die casting. The bearing 51 is provided with a cylindrical shaft portion 51a, and a through hole 51c into which an operation shaft is inserted is formed in the shaft portion 51a.

  The operation shaft 52 is made of an insulating material such as synthetic resin and is formed in a substantially cylindrical shape. An operating portion 52a is provided at the front end portion of the operating shaft 52 so as to pass through the through hole 51c of the bearing 51 and project outward, and a substantially disc-shaped rotating body 52b is formed at the rear end portion. Has been. A fitting shaft 52c is formed at the center of the lower surface side of the rotating body 52b, and a slider 53 made of a metal plate or the like as a conductive material is fixed to the outside of the fitting shaft 52c. In addition, on the upper surface side of the rotator 52b, an uneven portion 52g composed of a plurality of ridges and valleys that are concentrically continuous is formed.

The driving body 54 is made of an insulating material such as a synthetic resin and is formed in a substantially ring shape. In addition, a concavity and convexity portion 54c is formed on one surface of the driving body 54. The concavity and convexity portion 54c includes a plurality of contiguous peaks and valleys.
The spring member 55 is made of a metal plate having a spring property such as a phosphor bronze plate or a stainless steel plate, and is formed in a substantially ring shape. The spring member 55 is bent in an upright state to form a spring piece 55c. The spring member 55 urges the driving body 54 toward the rotating body 52b.

  The resistance substrate 56 is made of an insulating substrate such as a phenol resin, and an arc-shaped resistor (not shown) formed by printing carbon ink or the like is provided on one surface thereof. Further, terminals 58 are fixed to both ends of the resistor by eyelets 57.

  The housing 59 is for holding the resistance substrate 56, the terminal 58, and the like inside. The housing 59 is made of an insulating material such as synthetic resin, and the resistance substrate 56 is integrally formed by a method such as insert molding. In the center of the housing 59, a fitting hole 59a penetrating with the resistance substrate 56 is provided, and the front surface of the housing 59 is used for attaching a frame 60 that constitutes a lid for electrical components. A boss (not shown) is formed.

JP 2000-277308 A

  However, in the conventional variable resistor structure, when an insulating substrate made of phenol resin or the like is insert-molded into a housing made of an insulating material such as synthetic resin, a very small gap is generated between the insulating substrate and the synthetic resin. It will be a thing. And when the metal transition (whisker or migration) of the plating material of a terminal generate | occur | produced, there existed a problem that between terminals would short-circuit through this clearance gap.

  Accordingly, the present invention solves the above-described problems, and provides a highly reliable variable resistor that is less likely to cause a short circuit between terminals even when an insulating substrate is insert-molded in a synthetic resin housing. With the goal.

In order to solve the above-mentioned problem, in the present invention, as a first solving means, a flat insulating substrate on which a resistor and a current collector are formed, and a plurality of mounting holes provided on one end side of the insulating substrate, The resistors and the current collector are fixed to the plurality of mounting holes and are electrically connected to the resistors and the current collector, respectively, and a plurality of terminals extending outward from one end side of the insulating substrate, and the resistors and the current collector are exposed. comprising the plurality of holding members of the fastening portion and the insulating substrate and made buried synthetic resin terminal state, and a slider that slides on the resistor and the current collector, the plurality of the insulating substrate Insulating protrusions extending in a direction intersecting with the flat plate surface facing the holding member in the insulating substrate embedded in the holding member are provided between the fixing portions of the plurality of terminals fixed to the mounting holes. provided, embedded in the holding member and the holding member by the ridge Was configurations you to block a gap along said flat surface of the insulating substrate that occurs between the insulating substrate.

As a second solution, a concave groove or a slit is provided between the fixed portions of the plurality of terminals of the insulating substrate, and the resin of the synthetic resin holding member is provided in the groove or slit. It was set as the structure which formed the said protrusion part by filling a part.
As a third solution, the groove or slit is provided continuously to the edge of the insulating substrate.
As a fourth solution, the protrusions are formed by applying an insulating adhesive on the flat surface of the insulating substrate between the fixed portions of the plurality of terminals.
As a fifth solution, the protrusions are provided on both sides of the insulating substrate.
As a sixth solution, the surface of the terminal is tin-plated.

  As described above, the variable resistor of the present invention includes a flat insulating substrate on which a resistor and a current collector are formed, a plurality of mounting holes provided on one end side of the insulating substrate, and a plurality of mounting holes. A plurality of terminals fixedly connected to the resistor and the current collector and extending outward from one end of the insulating substrate; and a plurality of terminals fixed in a state where the resistor and the current collector are exposed. A holding member made of synthetic resin in which an insulating substrate is embedded, and a slider that slides on the resistor and the current collector, and between the fixing portions of a plurality of terminals fixed to the insulating substrate, the insulating substrate Insulating ridges that extend in the direction intersecting the flat plate surface of the metal plate prevent the transition and transition of metal such as plating material applied to the terminals between adjacent terminals. Therefore, a short circuit between terminals is less likely to occur, and reliability is improved.

Further, a groove portion or a slit portion that penetrates is provided between the fixing portions of the plurality of terminals of the insulating substrate, and the protrusion portion is formed by filling a part of the resin of the synthetic resin holding member into the groove portion or the slit portion. Therefore, when the insulating substrate is insert-molded into the synthetic resin holding member, the protruding portion can be formed with a part of the resin, so that productivity is good.
Further, since the groove portion or the slit portion is continuously provided up to the edge of the insulating substrate, the protrusion is formed to the edge of the insulating substrate, so that the effect of suppressing the transition and transition of the metal is improved.
Further, since the protrusions are provided on both sides of the insulating substrate, the transition and migration of the metal generated on both sides of the insulating substrate can be suppressed, and the effect can be improved.
Further, since the surface of the terminal is tin-plated, it is possible to realize lead-free since it is not covered with solder, and it is possible to suppress a short circuit between the terminals due to generation of whisker due to tin.

  Embodiments of the present invention are shown in FIGS. 1 is a cross-sectional view showing a variable resistor according to the present invention, FIG. 2 is a front view showing an insulating substrate and a holding member according to the present invention, FIG. 3 is a cross-sectional view taken along line 3-3 in FIG. 4 is a sectional view taken along line 4-4, FIG. 5 is a front view showing the insulating substrate to which the terminal of the present invention is fixed, FIG. 6 is a rear view, FIG. 7 is a sectional view taken along line 7-7 in FIG. It is a front view which shows the insulated substrate of invention.

  In the figure, the variable resistor of the present invention has an operating shaft 1, a bearing 2 that rotatably holds the operating shaft 1, and a leaf spring 4 for torque output, and rotates as the operating shaft 1 rotates. A movable body 3 and a slider 6, a slider receiver 5 which is engaged with the driver 3 and can rotate together with the driver 3, and a resistor 8 and a current collector with which the slider 6 slides. An insulating substrate 7 provided with a body 9 and integrally embedded in the holding member 11, a terminal 10 fixed to the insulating substrate 7, and a cover 12 covering the back side of the holding member 11.

  The operation shaft 1 is made of an insulating material such as synthetic resin or a metal material such as aluminum, and has an operation portion 1a that protrudes outward from the bearing 2, a shaft portion 1b that is rotatably inserted into the bearing 2, and a shaft portion. And a non-circular drive portion 1c protruding rearward of 1b. The drive unit 3 is engaged with the drive unit 1c, and the drive unit 3 rotates as the operation shaft 1 rotates.

  The bearing 2 is formed by die-casting a metal material such as zinc, and has a base portion 2a and a cylindrical portion 2b. The shaft portion 1b of the operation shaft 1 is inserted into the cylindrical portion 2b, and the drive portion 1c is projected from the base portion 2a side.

  The driving body 3 is made of an insulating material such as synthetic resin, and has a disk-shaped substrate portion 3a having a non-circular hole (for example, a small hole) 3c through which the driving portion 1c of the operation shaft 1 is inserted in the center, and the substrate portion 3a. The stopper part 3b protruded from the outer periphery. In addition, a pair of arc-shaped convex portions 3d that are opposed to each other with the hole interposed therebetween are provided on the peripheral edge of the non-circular hole 3c. Thus, the slider receiver 5 is engaged with the driving body 3 so as to be rotatable.

  Further, a plate spring 4 for torque output made of a metal plate having elasticity is attached to one surface side (surface side facing the bearing 2) of the substrate 3a of the driving body 3, and the driving body 3 rotates. At this time, the leaf spring 4 is in sliding contact with the inner surface of the base portion 2a of the bearing 2 so that torque is generated when the operation shaft 1 rotates (occurrence of profound feeling).

  The slider receiver 5 is formed in a disc shape from an insulating material such as a synthetic resin, and has a circular hole 5a through which the driving portion 1c of the operation shaft 1 is inserted at the center. A pair of arcuate convex portions (not shown) opposed to each other with the hole interposed therebetween, and a pair of concave portions (not shown) located between the convex portions are provided. The arcuate convex portion 3d of the driving body 3 is fitted into the pair of concave portions.

  Further, a slider 6 made of a conductive metal plate having elasticity is fixed to one surface side of the slider receiver 5 (the surface side on which the driving body 3 is located). The slider 6 has an annular base portion 6a and a contact portion 6b bent elastically from the base portion 6a, and a plurality of base portions 6a provided on one surface side of the slider receiver 5. The boss 5b is fixed by a method such as caulking. The slider 6 is rotated together with the slider receiver 5 so as to be in sliding contact with the resistor 8 and the current collector 9 formed on the insulating substrate 7.

  The insulating substrate 7 is made of a resin laminate such as phenol resin, and is formed in a flat plate shape having a slightly larger through hole 7a in the center. Further, as shown in FIG. 8, an annular current collector 9 is provided on one surface side (surface side) of the insulating substrate 7 so as to surround the periphery of the through hole 7 a. An arc-shaped resistor 8 that is partially open is provided around the periphery. In this case, the resistor 8 is formed, for example, by printing a carbon paste, and the current collector 9 is formed by, for example, printing a silver paste and overcoating carbon to prevent silver sulfidation. Yes.

  In addition, lead portions 8 a and 9 a extending from both ends of the resistor 8 and the center of the current collector 9 toward one end of the insulating substrate 7 are provided. Electrode portions 8b and 9b are provided on the leading ends of the lead portions 8a and 9a, respectively. These electrode portions 8b and 9b are printed with silver paste with a predetermined length and partially coated with carbon. Is formed. In addition, a part of the electrode portions 8b and 9b on the front end side is in a state where a silver pattern formed by printing a silver paste is exposed, and the terminal 10 is fixed on the silver pattern and the resistor 8 In addition, the current collector 9 is electrically connected.

In addition, a plurality of mounting holes 7b, 7b made of small holes penetrating the front and back of the insulating substrate 7 are provided in the central portions of the electrode portions 8b, 9b, and conductive metal is provided in the mounting holes 7b, 7b. A plurality of terminals 10 and 10 made of a plate are fixed by caulking eyelet portions 10a (see FIGS. 5 to 7). In this case, the terminal 10 is nickel-plated and then tin-plated on the upper surface side. Then, by fixing the terminal 10 to the attachment hole 7b, the terminal 10, the resistor 8 and the current collector 9 are electrically connected to each other.
In other words, in this embodiment, the surface of the terminal 10 is not subjected to solder plating, and tin plating is performed instead of solder plating to achieve lead-free for environmental problems.

  In addition, a groove 7c that is concave in the direction perpendicular to the flat plate surface of the insulating substrate 7, that is, the thickness direction, is formed between the plurality of mounting holes 7b, 7b of the insulating substrate 7. The groove portion 7c is continuously formed in a long shape from the upper side of the mounting hole 7b to the edge of the insulating substrate 7 along the electrode portions 8b and 9b. The groove portion 7c is formed as shown in FIG. When the terminals 10 are fixed to the electrode portions 8b and 9b, they are formed so as to be positioned between the terminals 10. In addition, this groove part 7c is formed in the elongate shape in the range which shields all between the parts where the silver pattern which is a part of electrode part 8b, 9b was exposed.

Further, on the other surface side (back surface side) of the insulating substrate 7 facing the one surface on which the resistor 8 and the current collector 9 are formed, a concave shape is similarly formed in the plate thickness direction at a position facing the groove portion 7c. A groove portion 7d is formed. Similarly, the groove 7d is formed in a long continuous shape from above the mounting hole 7b to the edge of the insulating substrate 7, and the groove 7d is connected to the electrode portions 8b and 9b as shown in FIG. When 10 is fixed, each terminal 10 is caulked and is formed so as to be positioned between the eyelet portions 10a to be fixed portions. That is, similar groove portions 7c and 7d are provided opposite to both surface sides of the insulating substrate 7, and these groove portions 7c and 7d are at least one surface side and the other surface of the insulating substrate 7 provided with the respective groove portions 7c and 7d. Each portion (fixed portion) of the terminal 10 on the side is formed in a long shape in a range in which it is partitioned in the extending direction of the terminal 10.

As a method for forming the grooves 7c and 7d, it can be easily formed by press working or the like, but it may be formed by applying laser processing to the front and back surfaces of the insulating substrate 7. The grooves 7c and 7d can be formed without the occurrence of the above. Further, the shape of the grooves 7c and 7d may be any of a V shape, a U shape, and a square shape, but the U shape is most suitable for workability and the like.
Although not shown in the drawings, instead of the grooves 7c and 7d, slit portions penetrating the front and back of the insulating substrate 7 are provided in a continuous manner from the top of the mounting hole 7b to the edge of the insulating substrate. Also good.

  The holding member 11 is formed in a substantially rectangular shape with an insulating material such as synthetic resin. As shown in FIGS. 2 and 3, an insulating substrate 7 is integrally embedded in the holding member 11 by a method such as insert molding. A circular first opening 11a is formed on one surface side of the holding member 11, and the resistor 8 and the current collector 9 are disposed on the inner bottom of the first opening 11a. ing. In addition, the peripheral portion of the insulating substrate 7 and the fixing portion of the terminal 10 are integrally embedded by the holding member 11, and the terminal 10 protrudes from the bottom surface side (the lower side in FIGS. 2 and 3) of the insulating substrate 7. Is formed.

  In addition, the grooves 7 c and 7 d provided between the fixing portions of the terminals 10 of the insulating substrate 7 are filled with a part of the resin of the synthetic resin holding member 11 when embedded in the holding member 11. As a result, the ridges 11b and 11c projecting along the shape of the grooves 7c and 7d are formed. The protruding portions 11b and 11c protrude (extend) between the fixing portions of the plurality of terminals 10 of the insulating substrate 7 in a direction orthogonal to the flat surface of the insulating substrate 7, as shown in FIG. As described above, the protrusions 11 b and 11 c are formed on both sides of the insulating substrate 7.

  In this embodiment, the surface of the terminal 10 is tin-plated instead of solder-plated, and lead-free can be realized because the solder is not covered. In this case, whisker is generated by tin. As a result, the terminals 10 and 10 may be short-circuited. In order to prevent this, in this embodiment, concave groove portions 7c and 7d are provided between the fixing portions of the plurality of terminals 10 of the insulating substrate 7, and a holding member made of synthetic resin is provided in the groove portions 7c and 7d. The protrusions 11b and 11c are formed by filling a part of the resin 11.

  At the time of insert molding of the insulating substrate 7 and the holding member 11, the protruding portions 11 b and 11 c form a wall, and the insulating substrate generated between the insulating substrate 7 and the holding member 11 at the time of insert molding by this wall. 7 can cut off a slight gap along the flat plate surface, so that it is possible to suppress a short circuit between the terminals 10 and 10 due to the generation of whisker due to tin that tends to extend straight. Yes.

  Further, in this case, the groove portions 7 c and 7 d are provided continuously to the edge of the insulating substrate 7 and are provided on both sides (front and back sides) of the insulating substrate 7. Since the portions 11b and 11c are formed, the effect of suppressing the transition and transition of the metal is improved.

  Further, the holding member 11 is provided with a through hole 11d in a square portion thereof, and the holding member 11 is inserted into the base portion of the bearing 2 by inserting a rivet 13 made of a rod-shaped metal material into the through hole 11d. 2a can be attached to the rear side. In addition, a circular second opening 11e is similarly provided on the other surface facing the first opening 11a provided on one surface of the holding member 11, and the second opening 11e is provided with the second opening 11e. A substrate portion 3 a of the driving body 3 is rotatably accommodated, and an arc-shaped convex portion 3 d is inserted into the through hole 7 a of the insulating substrate 7. Further, the second opening 11e is provided with a protruding protrusion 11f for stopper, and the rotation of the operation shaft 1 is restricted when the stopper 3b of the driving body 3 comes into contact with the protruding wall 11f. It has become.

  The first opening 11a accommodates the slider receiver 5, and is formed in a pair of recesses (not shown) provided between a pair of projections (not shown) provided on the periphery of the circular hole 5a. When the arcuate convex portion 3d of the driving body 3 inserted through the through hole 7a of the insulating substrate 7 is fitted, the slider receiver 5 and the driving body 3 can rotate together. That is, when the operating shaft 1 is rotated, the slider receiver 5 rotates as the driving body 3 rotates, and is insulated from the contact portion 6b of the slider 6 fixed to the slider receiver 5. The resistor 8 and the conductor 9 formed on the substrate 7 are in sliding contact.

  A rectangular cover 12 made of an insulating material such as synthetic resin is attached to the first opening 11a side of the holding member 11 and attached by caulking a rivet 13. That is, the holding member 11 is integrally attached while being sandwiched between the bearing 2 and the cover 12.

  According to the embodiment of the present invention described above, a plurality of mounting holes 7b are provided on one end side of the flat insulating substrate 7 on which the resistor 8 and the current collector 9 are formed, and the resistances are provided in the plurality of mounting holes 7b. A state in which the resistor 8 and the current collector 9 are exposed while being electrically connected to the body 8 and the current collector 9 and a plurality of terminals 10 extending outward from one end side of the insulating substrate 7 are fixed. Then, the fixing portions of the plurality of terminals 10 and the insulating substrate 7 are embedded in a holding member 11 made of synthetic resin, and concave grooves 7c and 7d are provided between the fixing portions of the plurality of terminals 10 of the insulating substrate 7. By providing a part of the resin of the holding member 11 made of synthetic resin in the grooves 7c and 7d, the grooves 7c and 7d extend in a direction perpendicular to the flat surface of the insulating substrate 7, that is, in the plate thickness direction. Since the insulating protrusions 11b and 11c are provided, this Insulating ridges 11b and 11c cause metal transition or migration (tin whisker or silver migration) such as a plating material made of tin or silver applied to terminals 10 and 10 between adjacent terminals 10 and 10. Therefore, the short circuit between the terminals 10 and 10 is less likely to occur, and the reliability is improved.

Further, since the protruding portions 11b and 11c are formed by filling a part of the resin of the holding member 11 made of synthetic resin, the insulating substrate 7 is inserted into the holding member 11 made of synthetic resin. When molding, the protrusions 11b and 11c can be easily formed with a part of the resin, so that the productivity is good.
The protrusions 11b and 11c in the present invention are not limited to those of the above-described embodiment formed by a part of the resin of the holding member 11, and for example, an insulating adhesive is applied on the flat surface of the insulating substrate 7. The adhesive may be formed in a direction intersecting with the flat plate surface of the insulating substrate 7 to form a protrusion.

It is sectional drawing which shows the variable resistor of this invention. It is a front view which shows the insulation board | substrate and holding member of the variable resistor of this invention. It is sectional drawing in the 3-3 line of FIG. 2 of this invention. FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. 2 of the present invention. It is a front view which shows the insulated substrate which fixed the terminal of the variable resistor of this invention. It is a rear view which shows the insulated substrate which fixed the terminal of the variable resistor of this invention. It is sectional drawing in the 7-7 line | wire of FIG. 5 of this invention. It is a front view which shows the insulation board | substrate of the variable resistor of this invention. It is sectional drawing which shows the conventional variable resistor.

Explanation of symbols

1: Operation shaft 1a: Operation portion 1b: Shaft portion 1c: Drive portion 2: Bearing 2a: Base portion 2b: Tubular portion 3: Drive body 3a: Substrate portion 3b: Stopper portion 3c: Non-circular hole 3d: Arc-shaped convex portion 4: Leaf spring 5: Slider receiver 5a: Circular hole 5b: Boss 6: Slider 6a: Base 6b: Contact portion 7: Insulating substrate 7a: Through hole 7b: Mounting hole 7c: Groove 7d: Groove 8: Resistance Body 8a: Lead part 8b: Electrode part 9: Current collector 9a: Lead part 9b: Electrode part 10: Terminal 10a: Eyelet part 11: Holding member 11a: First opening part 11b: Projection part 11c: Projection part 11d : Through hole 11e: Second opening 11f: Projection wall 12: Cover 13: Rivet

Claims (6)

A flat insulating substrate on which a resistor and a current collector are formed, a plurality of mounting holes provided on one end side of the insulating substrate, and fixed to the mounting holes and attached to the resistor and the current collector, respectively. A plurality of terminals extended outward from one end side of the insulating substrate, and the fixed portions of the plurality of terminals and the insulating substrate were embedded in a state where the resistor and the current collector were exposed. A holding member made of a synthetic resin and a slider that slides on the resistor and the current collector, and between the fixed portions of the plurality of terminals fixed to the plurality of mounting holes of the insulating substrate The insulating substrate embedded in the holding member is provided with an insulating protrusion extending in a direction intersecting with the flat plate surface facing the holding member, and the protrusion is embedded in the holding member and the holding member. On the flat surface of the insulating substrate generated between the insulating substrate and the insulating substrate. Variable resistor, characterized in that so as to block the gap that Tsu.   A concave groove portion or a through slit portion is provided between the fixing portions of the plurality of terminals of the insulating substrate, and the protrusion is obtained by filling a part of the resin of the synthetic resin holding member into the groove portion or the slit portion. The variable resistor according to claim 1, wherein a strip is formed.   3. The variable resistor according to claim 2, wherein the groove or slit is continuously provided up to an edge of the insulating substrate. The variable resistor according to claim 1, wherein the protrusion is formed by applying an insulating adhesive on a flat plate surface of the insulating substrate between the fixed portions of the plurality of terminals. The variable resistor according to claim 1 , wherein the protrusions are provided on both sides of the insulating substrate. The variable resistor according to claim 1 , wherein a surface of the terminal is tin-plated.

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