JPWO2009050982A1 - Variable resistor - Google Patents

Abstract

The present invention provides a variable resistor having a structure capable of reducing the production cost by reducing the number of components and reducing the number of assembly steps. A rotating shaft (2) in which a large-diameter part (2a) to which the slider (2b) is attached is integrally molded with resin, is rotatably held in an exterior case (3) made of resin, and a plurality of columnar pin terminals (4b1-4b3) is exposed on one main surface, and the connector part (4a) from which the pin terminals (4b1-4b3) protrude from the other is insert-molded. On the main surface, a current collector (42) and a resistor (43) are formed so as to be electrically connected to the exposed end faces of the pin terminals (4b1 to 4b3), and this resin substrate (4) is connected to a slider ( A variable resistor (1) obtained by fitting and fixing to the outer case (3) so that 2b) contacts the current collector (42) and the resistor (43).

Description

  The present invention relates to a rotary variable resistor whose resistance is variable by rotating a rotary shaft, and more particularly to the structure of a connector-integrated variable resistor.

  Rotating variable resistors are used in various electric devices such as television receivers, radio receivers, video tape recorders, etc., or vehicles or other electric devices. Also, as a recent trend, the use of solder containing lead is restricted from the viewpoint of environmental protection, and connectors are formed in these variable resistors, and electrically connected to external circuits such as circuit boards through the connectors to the variable resistors The structure to begin to be adopted.

  As a variable resistor in which such a connector is formed, a variable resistor having a structure as in Patent Document 1 is known. Hereinafter, the structure of the variable resistor of Patent Document 1 will be described with reference to FIG.

  As shown in FIG. 7, the variable resistor 101 includes a rotating shaft 102, an exterior case 103, a substrate 104, and a lower cover 105.

  A slider mounting plate 102a is attached to the tip of the rotating shaft 102, and a slider 102b is attached to the lower surface thereof.

  The outer case 103 holds the rotating shaft 102 rotatably.

  A resistor (not shown) is formed on the upper surface of the substrate 104, and the positional relationship is set such that the slider 102b slides on the resistor.

  The lower cover 105 can store and fix the substrate 104 and is combined with the exterior case 103 to form a storage space. The lower cover 105 is formed with a connector portion 105a that can be electrically connected to an external circuit.

  The connector portion 105a has a connector terminal 105b, and the connector terminal 105b is electrically connected to a resistor on the substrate 104 via the connection terminal 106.

  However, such a structure of the variable resistor 101 has a large number of components and requires a large number of assembly steps.

  Therefore, as described in Patent Documents 2 and 3, a variable resistor having a structure in which the number of components is reduced by integrally forming a substrate on which a resistor is formed and a lower cover on which a connector portion is formed is proposed. Has been. FIG. 8 is a cross-sectional view of the variable resistor of Patent Document 3 for explaining the structure of Patent Documents 2 and 3.

  As shown in FIG. 8, the variable resistor 201 includes a rotating shaft 202, an exterior case 203, and a substrate 204.

  A slider mounting plate 202a is attached to the tip of the rotating shaft 202, and a slider 202b is attached to the lower surface thereof.

  The outer case 203 holds the rotary shaft 202 rotatably.

  A resistor (not shown) is formed on the upper surface of the substrate 204, and the positional relationship is set such that the slider 202b slides on the resistor.

  The substrate 204 is combined with the outer case 203 to form a storage space. The board 204 is formed with a connector portion 204a that can be electrically connected to an external circuit.

  The connector part 204a has a connector terminal 204b. The connector terminal 204b is formed by bending a metal plate, a part of which is exposed on the upper surface of the substrate 204 and is electrically connected to a resistor not shown. ing.

  Compared to the structure shown in FIG. 7, the structure of the substrate and the lower cover becomes one point, and the assembly man-hours include the process of storing and fixing the board to the lower cover, and the connection terminals. It is possible to reduce the step of electrically connecting the resistor of the substrate and the connector terminal through the connector.

In the structures of Patent Documents 2 and 3, since the connector terminal 204b is formed by bending a metal plate, it is easy to bend into a desired shape, and mass production is easy by punching from a hoop material or the like. is there.
JP-A-8-5309 JP-A-8-153608 Japanese Patent Laid-Open No. 10-55906

  By the way, when the connector terminal 204b is formed by bending a metal plate and a part of the connector terminal 204b is exposed on the surface of the substrate 204, an exposed area that can be connected to a resistor on the substrate surface is required. Therefore, as in Patent Documents 2 and 3, the main surface of the metal plate is bent and exposed. It is preferable that the exposed surface be substantially flush with the surface of the substrate 204. This is because when the exposed surface is not substantially on the same plane as the surface of the substrate 204, an undesired convex portion is generated on the surface of the substrate 204, which may be an obstacle when printing resistors and electrodes on the substrate 204. This is because there arises a problem that it becomes an obstacle when the slider slides.

  However, when the connector terminal 204b is formed by bending the metal plate, it is difficult to bend it at 90 degrees due to the elasticity inherent in the metal plate. Further, when the substrate 204 is formed with resin, when the connector terminal 204b is embedded with an insert mold, the connector terminal 204b is arranged so that the exposed surface of the connector terminal 204b on the surface of the substrate 204 is substantially flush with the surface of the substrate 204. A supporting member is required.

  Therefore, in the variable resistor of FIG. 8, when the connector terminal 204b is embedded in the substrate 204 with an insert mold, a pressing pin is provided on the molding die to support the connector terminal 204b. The hole 204c in FIG. 8 is a trace of the pressing pin being removed.

  Such a complicatedly shaped mold hinders the miniaturization of the variable resistor and also requires attention when taking it out of the mold.

  Further, since the shape is complicated, it causes a processing variation, and as a result, there is a concern about variation in characteristics of individual variable resistors.

  The present invention has been made in view of the above points, and provides a variable resistor having a structure capable of reducing the production cost by reducing the number of components and the number of assembly steps.

  That is, the variable resistor according to claim 1 of the present invention includes a rotating shaft, a current collector to which a slider disposed at a tip of the rotating shaft is connected, and a resin substrate on which a resistor is formed; An external case having an opening for holding and fixing the rotation of the resin substrate while holding the rotation shaft in a rotatable manner, the variable resistor including the collector on one main surface of the resin substrate. An electric body and the resistor are formed, and a connector portion is integrally formed on the other main surface of the resin substrate, and the connector portion protrudes from the one main surface of the resin substrate through the other main surface. A connector terminal comprising a plurality of columnar pin terminals and a frame projecting from the other main surface of the resin substrate so as to surround the connector terminal, one end of the plurality of pin terminals being one main of the resin substrate Exposed to the surface A plurality of pin terminals, the end surfaces of some of the pin terminals are electrically connected to the current collector, and the end surfaces of the remaining pin terminals of the plurality of pin terminals are the resistance It is characterized by being electrically connected to the body.

  The variable resistor according to claim 2 of the present invention has a side surface in which the pin terminal extends from one end to the other end, and the shaft movement restraining portion for restricting the pin terminal from moving in the axial direction on the side surface. It is characterized by providing.

  Furthermore, the variable resistor according to claim 3 of the present invention is characterized in that the axial movement restraining portion of the pin terminal is a convex portion protruding from the side surface and continuing in a radial direction centering on the axis of the pin terminal. It is what.

  According to a fourth aspect of the present invention, the variable resistor has a side surface in which the pin terminal extends from one end to the other end, and the rotation restraining portion that restricts the pin terminal from rotating about an axis on the side surface. It is characterized by providing.

  In the variable resistor according to claim 5 of the present invention, the resin substrate has an edge surface extending between the one main surface and the other main surface, and the edge surface extends toward the other main surface. And an engagement portion is formed on the surface of the extension wall and is engaged with an engagement receiving portion formed on the inner wall of the opening of the exterior case, whereby the exterior case and the resin substrate are formed. Is fitted and fixed.

  The variable resistor of the present invention uses a plurality of columnar pin terminals for the connector terminal, and the end surface of the pin terminal is exposed on one main surface of the resin substrate. It is easy to set so as to be substantially flush with the surface of the resin substrate. Also, when insert molding a pin terminal on a resin substrate, the end face of one mold and the end face of the columnar pin terminal are brought into contact with each other, and the end of the columnar pin terminal is opposite to the hole opened in the other mold. By inserting and supporting the pin terminals, the pin terminals can be easily arranged, and the mold is not complicated as in Patent Document 3.

  Further, in the variable resistor according to claim 2 of the present invention, since the axial movement restraining portion such as the concave portion or the convex portion is formed on the side surface of the pin terminal, it can be restrained from moving in the axial direction. That is, when another connector is inserted into the connector portion, a force is applied in the axial direction of the pin terminal so that the pin terminal does not protrude from one main surface of the resin substrate. Thereby, as a result of the pin terminal moving in the axial direction, a force is applied to the resistor and the current collector connected to the end surface of the pin terminal to cause separation and a problem of connection failure is suppressed. Further, when the shaft movement restraining portion is a convex portion, when the pin terminal is insert-molded on the resin substrate, the convex portion can be used for positioning in the pin terminal axial direction. It becomes easier to make the surface and the surface of the resin substrate substantially the same plane.

  Furthermore, in the variable resistor according to claim 3 of the present application, the pin terminal axial movement restraining portion is formed by a convex portion that protrudes from the side surface and is continuous in the radial direction about the axis of the pin terminal. Thus, when the pin terminal is insert-molded on the resin substrate, the convex portion can be used for positioning in the pin terminal axial direction. The projecting portion serves as a lid for the pin terminal holding hole opened in the other mold, and the resin can be prevented from flowing into the pin terminal holding hole. As a result, it is possible to prevent undesired resin from adhering to the connection portion of the connector terminal.

  In the variable resistor according to claim 4 of the present application, since the rotation restraining portion that restricts the rotation about the axis is formed on the side surface of the pin terminal, the rotation about the axis can be restrained. In other words, by rotating the pin terminal around such an axis, the resistor or current collector connected to the end face of the pin terminal is applied with force, and the problems such as separation and poor connection are suppressed. Yes.

  In the variable resistor according to claim 5 of the present application, the resin substrate has an edge surface extending between the one main surface and the other main surface, and the edge surface has an extension wall extended to the other main surface side. Then, an engaging portion is formed on the surface of the extension wall, and the outer case and the resin substrate are fitted and fixed by being engaged with an engagement receiving portion formed on the inner wall of the opening of the outer case. Thus, the resin substrate has an extension wall having an engaging portion, and this extension wall can be overlapped with the inner wall of the outer case opening, and the engaging portion of the extension wall is provided on the inner inner wall of the outer case. Since it is engaged and fixed by engaging with the received engagement receiving portion, it is easy to assemble and can be securely fixed.

It is a figure which shows the variable resistor 1 which concerns on embodiment of this invention, (A) is sectional drawing of the variable resistor 1, (B) is the top view which looked at the variable resistor 1 from the connector part 4a side. It is a figure which shows the resin substrate 4 which concerns on embodiment of this invention, (A) is the top view seen from the one main surface side of the resin substrate 4, (B) is the XX sectional drawing of (A). . FIG. 3 is a cross-sectional view of an outer case 3 according to an embodiment of the present invention. It is a figure which shows the rotating shaft 2 which concerns on embodiment of this invention, (A) is a front view of the rotating shaft 2, (B) is the front view seen from the large diameter part 2a lower surface of the rotating shaft 2. FIG. It is a figure which shows pin terminal 4b1 which concerns on embodiment of this invention, (A) is a front view of pin terminal 4b1, and a YY sectional view, (B)-(D) is a front view of the modification of a pin terminal. And FIG. FIG. 5 is an enlarged cross-sectional view of a connector portion 4 portion during resin molding of a resin substrate 4 according to an embodiment of the present invention. It is sectional drawing of the conventional variable resistor based on patent document 1. FIG. It is sectional drawing of the conventional variable resistor based on patent document 3. FIG.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1A is a cross-sectional view of the variable resistor 1, and FIG. 1B is a plan view of the variable resistor 1 viewed from the connector portion 4a side. 2A is a plan view seen from one main surface side of the resin substrate 4, and FIG. 2B is a cross-sectional view taken along the line XX of FIG. FIG. 3 is a cross-sectional view of the outer case 3 before the rotating shaft 2 and the resin substrate 4 are attached. 4A is a front view of the rotary shaft 2, and FIG. 4B is a front view of the rotary shaft 2 as viewed from the bottom surface of the large-diameter portion 2a.

  As shown in FIG. 1A, the variable resistor 1 has a rotating shaft 2, an outer case 3, and a resin substrate 4. A large-diameter portion 2a is provided on one end side of the rotating shaft 2, and a slider 2b is attached to the lower surface thereof. The outer case 3 holds the rotary shaft 2 in a rotatable manner. The resin substrate 4 is fitted into the outer case 3 to form a storage space. The resin substrate 4 is formed with a connector portion 4a that can be electrically connected to an external circuit. As shown in FIG. 1B, the connector portion 4a has connector terminals constituted by a plurality of columnar pin terminals 4b1 to 4b3.

  As shown in FIGS. 2A and 2B, the end surfaces of the columnar pin terminals 4 b 1 to 4 b 3 are exposed on one main surface of the resin substrate 4. Further, as shown in FIG. 2A, an electrode 44 is disposed and electrically connected on the exposed end face of the pin terminal 4b1, and an annular current collector 42 is extended on the exposed end face of the pin terminal 4b2. The portion 42a is disposed and electrically connected, and the electrode 45 is disposed and electrically connected on the exposed end surface of the pin terminal 4b3. Furthermore, one end of the resistor 41 is disposed on the electrode 44, and the other end of the resistor 41 is disposed on the electrode 45 and electrically connected thereto.

  A lubricating film 43 is formed on the current collector 42 so as to cover the current collector 42. The lubricating film 43 is for protecting the current collector 42 when the slider 2b of FIG.

  Further, as shown in FIGS. 2A and 2B, a concave portion 4c is formed inside the annular current collector 42 on one main surface of the resin substrate 4. This is for receiving the convex part 2c formed in the center of the lower surface of the large diameter part 2a of the rotating shaft 2, as shown in FIG. As a result, even if the rotary shaft 2 is rotated, no axial deviation occurs. The groove 4d on the bottom surface of the concave portion 4c is for storing a lubricant for suppressing the convex portion of the rotary shaft 2 and the concave portion 4c of the resin substrate 4 from being worn by rotation.

  In addition, as shown in FIG. 2B, the resin substrate 4 has an extension wall 4e extended to the other main surface side opposite to the one main surface on which the resistor 41 and the current collector 42 are formed. ing. Further, an engaging portion 4f is formed to project from the surface of the extension wall 4e.

  Furthermore, as shown in FIG. 3, the exterior case 3 has a holding hole 3a in which the rotating shaft 2 is inserted and rotatably held.

  The exterior case 3 has an opening 3b for accommodating and fixing the resin substrate 4 therein. In the opening 3b, there is formed a slit 3c for holding the resin substrate 4 by elasticity while allowing the resin substrate 4 to be accommodated flexibly. An engagement receiving portion 3d that engages with an engagement portion 4f formed on the surface of the extension wall 4e of the resin substrate 4 shown in FIG. 2B is formed on the inner wall of the opening 3b. Further, the outer case 3 has a rotation stopper 3e for rotational positioning when the variable resistor 1 is attached to a panel (not shown).

  4 (A) and 4 (B), the rotary shaft 2 has a large diameter portion 2a on one end side thereof, and a concave portion provided on one main surface of the resin substrate 4 at the center of the lower surface thereof. A convex portion 2c to be inserted into 4c is formed. Further, three caulking portions 2d are formed on the lower surface of the large diameter portion 2a, whereby the slider 2b is attached to the lower surface of the large diameter portion 2a. In addition, a recess 2e is formed on the lower surface of the large diameter portion 2a in order to generate a predetermined distance with respect to the lower surface of the large diameter portion 2a and the sliding contacts 2b1 and 2b2 of the slider 2b.

  The sliding contact 2b1 of the slider 2b slides on a resistor 41 on one main surface of the resin substrate 4, and the sliding contact 2b2 of the slider 2b is a current collector on one main surface of the resin substrate 4. It is arranged so as to slide on the lubricating film 43 covering 42. The reason why the sliding contacts 2b1 and 2b2 are divided into a plurality of parts is to ensure contact during sliding.

  Next, a columnar pin terminal serving as a connector terminal of the present invention will be described with reference to FIG. Since the other pin terminals 4b2 and 4b3 in the above-described embodiment are configured in the same manner as the pin terminal 4b1, the pin terminal 4b1 will be described as an example. FIG. 5A is a front view of the pin terminal 4b1 used in the above-described embodiment and a cross-sectional view taken along line YY shown above. 5B to 5D are modified examples of the pin terminal 4b1.

  The pin terminal 4b1 is obtained by molding a wire made of a copper alloy such as brass by header processing that is cold plastic processing. The metal constituting the wire may be iron or white. In the case of copper alloy or iron, surface treatment is performed by gold or tin plating in order to prevent oxidation or conductivity of the wire surface. In the case of white, such a surface treatment can be eliminated. Moreover, although cutting may be used together at the time of header processing, it is preferable to perform the header processing as much as possible because material loss is caused accordingly.

  One end of the pin terminal 4b1 is formed with an end face 4b1a which is an exposed end face on one main surface of the resin terminal shown in FIGS. 2A and 2B, and the other end is a counterpart terminal when used as a connector terminal. A taper 4b1b is provided as shown in FIG. 5 so as to facilitate insertion into the connector hole.

  An axial movement restraining portion 4b1c is formed on the side surface extending from one end to the other end of the pin terminal 4b1. When the mating connector is inserted into the connector portion 4a shown in FIG. 1 (A), the pin terminal 4b1 moves in the axial direction by the shaft movement restraining portion 4b1c, and the resin substrate shown in FIG. 1 (A). 4 is prevented from protruding toward the main surface. In FIG. 5, the axial movement restraining portion 4b1c is a convex portion that is continuous in the radial direction about the axis of the pin terminal 4b1. Concerning the effect of restraining the axial movement, the convex part does not have to be continuous, and the same effect can be obtained by forming the axial movement restraining part as a concave part and resin molding so that the resin of the resin substrate 4 wraps around that part. Although it is obtained, in consideration of the strength of the pin terminal, it is preferable that the convex part is continuous in the radial direction about the axis of the pin terminal.

  Further, as shown in FIG. 5A, a rotation restraining portion 4b1d is formed between the end face 4b1a and the shaft movement restraining portion 4b1c on the side surface of the pin terminal 4b1. As shown in FIG. 5A, the Y-Y line cross section is shown at the top, the rotation restraining portion 4b1d has a flat cross section, and as shown in the front view of FIG. It has a shape protruding from. By adopting such a shape, when a force is applied in the direction in which the pin terminal 4b1 rotates about the axis, the rotation restraining portion 4b1d cooperates with the resin of the resin substrate 4 to restrain the rotation of the pin terminal 4b1. can do.

  Next, a modified example of the pin terminal 4b1 will be described with reference to FIGS. The same parts as those of the pin terminal 4b1 in FIG. 5A are denoted by the same reference numerals and detailed description thereof is omitted.

  The pin terminal 5b1 differs from the pin terminal 4b1 in FIG. 5A in the shape of the rotation restraining portion 5b1d. That is, as shown in FIG. 5 (B), the rotation restraining part 5b1d has a shape in which a plurality of projecting parts are projected in a radial direction centered on the axis. As a result, since the resin of the resin substrate 4 enters the valleys between the protruding portions in the rotation restraining portion 5b1d, the rotation can be restrained against a stronger force than the rotation restraining portion 4b1d of the pin terminal 4b1. .

  As shown in FIG. 5C, the pin terminal 6b1 has a shape in which the rotation inhibiting portion 6b1d protrudes the protruding portions at two locations on the side surface of the pin terminal 6b1. Since this structure has a simpler shape than the rotation restraining portion 5b1d in FIG. 5B, it is easy to process. Further, it can be said that the structure is stronger against bending in the length direction of the pin terminal 6b1 than the flat rotation restraining portion 4b1d of FIG.

  As shown in FIG. 5D, the pin terminal 7b1 differs from the pin terminal 6b1 in FIG. 5C in the shape of the end face 7b1a. The end surface 7b1a is formed with a large-diameter portion having an area larger than the cross-sectional area perpendicular to the axial direction of the main portion of the pin terminal 7b1. The end surface 7b1a of the pin terminal 7b1 is an exposed end surface on one main surface of the resin terminal shown in FIGS. 2A and 2B. The suppression effect can be increased, and the contact area with the current collector 42 and the electrodes 44 and 45 in FIGS. 2A and 2B can be increased, and the reliability of electrical connection can be increased.

  Next, a method for manufacturing the variable resistor 1 according to the present invention will be described with reference to the drawings.

  First, the rotating shaft 2 shown in FIG. 4 is formed by resin molding. The large diameter portion 2a, the convex portion 2c, the caulking portion 2d, and the concave portion 2e are integrally formed by this resin molding. The resin used for the production includes PPS resin, LCP resin, PBT resin, polyamide resin, and the like, but a grade containing a lubricating material such as PTFE is preferable. Further, it is preferable to eliminate the glass fiber or make it as small as possible. This is because when there is a portion where friction occurs between the outer case 3 and the resin substrate 4 when the rotary shaft 2 is rotated, wear due to this friction is reduced.

  Then, it slides on the lower surface of the large-diameter portion 2a of the rotating shaft 2 by heat caulking through the caulking portion 2d of the rotating shaft 2 into the hole of the slider 2b formed by pressing a metal plate hoop material such as a copper alloy. Install the child 2b. The caulking portion 2d can be molded using ultrasonic caulking or the like in addition to thermal caulking.

  Further, the outer case 3 shown in FIG. 3 is also formed by resin molding. The holding hole 3a, the opening 3b, the slit 3c, the engagement receiving portion 3d, and the rotation stopper 3e are integrally formed by this resin molding. The resin used for manufacturing includes PPS resin and LCP resin as well as PPS resin and polyamide resin in the same manner as the rotating shaft 2, but for the same reason as the rotating shaft 2, a grade containing a lubricating material such as PTFE. It is preferable that glass fiber is not mixed or is made as small as possible.

  Further, the resin substrate 4 shown in FIG. 2 is also formed by resin molding. The connector 4a, the recess 4c, the groove 4d, the extension wall 4e, and the engagement portion 4f are integrally formed by this resin molding. In addition, as resin used for manufacture, PPS resin and LCP resin are preferable. This is because the resin substrate 4 is particularly required to have strength, moldability, heat resistance, and the like.

  Further, when the resin substrate 4 is resin-molded, pin terminals 4b1 to 4b3 are embedded by insert molding. This process will be described with reference to FIG. FIG. 6 is an enlarged cross-sectional view of the connector portion 4 when the resin substrate 4 is molded with resin.

  As shown in FIG. 6, a space matching the shape of the resin substrate 4 is formed between the upper mold 80a and the lower mold 80b, and the pin terminal 4b1 is for holding a terminal previously formed in the lower mold 80b. The resin substrate 4 is resin-molded by injecting the resin 90 into the space between the upper mold 80a and the lower mold 80b in this state.

  The end surface 4b1a of the pin terminal 4b1 is in contact with the lower surface of the upper mold 80a, and the resin 90 does not wrap around the end surface 4b1a when the resin 90 is injected. Therefore, end surface 4b1a is exposed on one main surface of completed resin substrate 4.

  The shaft movement restraining portion 4b1c of the pin terminal 4b1 defines the length that the pin terminal 4b1 protrudes from the terminal holding hole formed in the lower mold 80b. That is, the shaft movement restraining portion 4b1c is a convex portion that is continuous in the radial direction about the axis of the pin terminal 4b1, and protrudes from the main portion of the pin terminal 4b1, so that it is formed in the terminal holding hole of the lower mold 80b. No further insertion. Therefore, by appropriately setting the length between the end surface 4b1a of the pin terminal 4b1 and the axial movement restraining portion 4b1c, the end surface 4b1a of the pin terminal 4b1 is positioned so as to be in contact with the lower surface of the upper mold 80a. Function. Further, since the axial movement restraining portion 4b1c is a convex portion that continues in the radial direction around the axis of the pin terminal 4b1, it completely covers the terminal holding hole of the lower mold 80b. As a result, even if there is a slight gap between the side surface of the pin terminal 4b1 and the terminal holding hole of the lower mold 80b, the resin 90 is injected into the space between the upper mold 80a and the lower mold 80b. Then, the resin 90 can be prevented from flowing into this gap. Therefore, when the pin terminal 4b1 is used as a connector terminal, it is possible to prevent undesired resin from adhering to the portion used for electrical connection, and to prevent such defective products from being manufactured. Therefore, the yield can be improved and the production cost can be reduced.

  Next, on the one main surface of the resin substrate 4 thus resin-molded, the annular current collector 42 having the extended portion 42a and the electrodes 44 and 45 print the conductive paste in a predetermined shape in a predetermined position. It is formed by heat treatment. As the conductive paste, a conductive resin containing silver particles is preferable. The current collector 42 and the electrodes 44 and 45 are preferably formed at the same time from the viewpoint of reducing the number of processes. However, when the current collector 42 and the electrodes 44 and 45 are made of different materials, the printing process is separated. good. As a result of printing and heat treatment of this conductive paste, the exposed end face of the pin terminal 4b1 and the electrode 44, the exposed end face of the pin terminal 4b2 and the extended portion 42a of the current collector 42, and the exposed end face of the pin terminal 4b3 and the electrode 45 are electrically connected, respectively. Connected.

  Next, the resistor 41 is formed in an arc shape so as to cover the electrodes 44 and 45 and surround the current collector 42 by printing and heat-treating a resistor paste containing carbon.

  A lubricating film 43 is formed on the current collector 42 by printing and heat treatment. The lubricating film 43 is for protecting the current collector 42 when the slider 2b slides, and needs to be a material having lubricity and conductivity. Although the resistance value is slightly increased by the lubricating film 43, the current collector 42 is disposed below the lubricating film 43, and the resistance value is increased by the thickness of the lubricating film 43. It doesn't matter. Therefore, a resistor paste containing carbon can be used in the same way as the resistor 41. When the same material is used, the number of steps can be reduced because the resistor 41 can be printed and heat-treated simultaneously. , Production cost can be reduced.

  The variable resistor 1 as shown in FIG. 1 can be obtained by preparing the rotating shaft 2, the outer case 3, and the resin substrate 4 as described above and assembling them.

  First, the rotating shaft 2 is inserted into the holding hole 3a of the outer case 3 and is held rotatably. Next, the resin substrate 4 is press-fitted into the opening 3 b of the outer case 3. At this time, the opening 3b of the outer case 3 is widened by the slit 3c provided in the opening 3b of the outer case 3, and the press-fitting of the resin substrate 4 is facilitated. After the press-fitting, the engaging portion 4f formed on the surface of the extension wall 4e of the resin substrate 4 is fitted into the engaging receiving portion 3d of the outer case 3.

  On the other hand, the outer case 3 has elasticity because it is resinous, and the force due to this elasticity is applied in a direction to return to the original shape. As the slit 3c part is expanded at one end, it will return to its original position.As a result, it works in the direction of pushing out the resin substrate 4, but the resin substrate 4 is pushed by the engagement between the engagement portion 4f and the engagement receiving portion 3d. Not issued. As a result, the resin substrate 4 is securely fitted and fixed to the outer case 3.

  As described above, since the variable resistor 1 according to the present invention can be constituted by the rotary shaft 2, the outer case 3, and the resin substrate 4, the number of components is small and assembling is easy as described above. Therefore, downsizing is easy and production costs can be greatly reduced.

  As described above, the present invention is useful for a variable resistor, and is particularly excellent in that the production cost can be reduced as compared with the case where the number of components is reduced and the number of assembly steps is reduced.

Claims (5)

A rotating shaft; a resin substrate on which a current collector and a resistor connected to a slider disposed at a tip of the rotating shaft are formed; and the rotating shaft is rotatably held and the resin substrate is accommodated. An exterior case having an opening for fitting and fixing, and a variable resistor,
The current collector and the resistor are formed on one main surface of the resin substrate,
A connector part is integrally formed on the other main surface of the resin substrate,
The connector portion protrudes from one main surface of the resin substrate from a main surface of the resin substrate so as to surround the connector terminal, and a connector terminal composed of a plurality of columnar pin terminals protruding through the other main surface. It consists of a frame and
One end of the plurality of pin terminals has an end surface exposed to one main surface of the resin substrate,
The end surface of a part of the plurality of pin terminals is electrically connected to the current collector,
The end face of the remaining pin terminal of the plurality of pin terminals is electrically connected to the resistor.
A variable resistor characterized by that.   The said pin terminal has a side surface extended from one end to the other end, The said side surface is equipped with the axial movement suppression part which controls that the said pin terminal moves to an axial direction, The Claim 1 characterized by the above-mentioned. Variable resistor.   The variable resistor according to claim 2, wherein the pin terminal axial movement restraining part is a convex part protruding from the side surface and continuing in a radial direction centering on the axis of the pin terminal.   The said pin terminal has a side surface extended from one end to the other end, The said side surface is provided with the rotation suppression part which controls that the said pin terminal rotates centering on an axis | shaft, The Claim 1 thru | or The variable resistor according to claim 3. The resin substrate has an edge surface extending between the one main surface and the other main surface, the edge surface has an extension wall extended to the other main surface side, and the extension wall surface has An engaging portion is formed,
The outer casing and the resin substrate are fitted and fixed by being engaged with an engagement receiving portion formed on the inner wall of the outer casing opening. 5. The variable resistor according to any one of items 4.

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