JPH0718403U - Variable resistor structure - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a variable resistor having a structure in which wobbling of a rotating shaft is prevented. A variable resistor 20 includes a rotary shaft 21, a seat 22 that pivotally supports the rotary shaft 21, a slider 11 attached to one end of the rotary shaft, and a resin provided with a lead terminal 23. The seat 22 has a substrate 31 and a horseshoe-shaped carbon film resistor 10 baked on the resin substrate 31, and further has the rotary shaft 21 fitted therein and axially supporting the rotary shaft 21.
Notch groove portions 27 at four locations on the peripheral wall 26 of the cylindrical bearing portion 24 of
And the inner surface 28 of the shaft bearing portion is provided with a taper Θ whose inner diameter is gradually narrowed toward the opening 29 of the rotary shaft protruding side, and the inner diameter Φ1 ′ of the peripheral edge 30 of the rotary shaft protruding side opening of the shaft bearing portion 24 contacts the rotary shaft. The structure is smaller than the diameter Φ2 '.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention mainly relates to the structure of a carbon film type variable resistor, and more particularly to the structure of a variable resistor that prevents wobbling of a rotating shaft.

[0002]

[Prior art]

 The conventional variable resistor is generally called a carbon film type variable resistor.The insulating resin plate made of bakelite or the like has a carbon film baked on it as a resistor. It is designed to change the resistance value by rotating it.

Although the basic structure remains unchanged, the downsizing of each component is progressing in order to meet the demand for further miniaturization of variable resistors in the recent trend of light, thin, short and small electronic devices. There is.

FIG. 4 is a partial cross-sectional view showing a structural example of a conventional variable resistor 15 having a general rotating shaft.

In the figure, a rotary shaft 1 made of metal or plastic is fitted into a fitting insertion hole 3 of a metal seat 2 that axially supports the rotary shaft 1, and has a cylindrical bearing portion 4, a collar portion 5, and one end surface. 6 is rotatably supported by a resin substrate 9 having a hole 8 into which the protrusion 7 of 6 is inserted.

A resistance substrate 14 having a horseshoe-shaped carbon film resistor 10 baked thereon is laid on the resin substrate 9, and the slider 11 attached to one end face 6 of the rotary shaft 1 has the carbon film. It has a structure in which it slides on the resistor 10 by rotation.

As far as the shaft support structure is concerned, the rotary shaft 1 is axially supported by the inner surface 12 of the bearing portion 4 and the hole 8 of the resin base plate 9, and the upper surface 13 of the flange portion of the rotary shaft 1 slides. It is supported perpendicularly to the carbon film resistor 10 by being pressed against the inner surface of the seat 2 by utilizing the metal elasticity of the child 11.

[0008]

[Problems to be solved by the device]

 However, in the conventional variable resistor 15 described above, the vertical supporting force of the shaft is not sufficient, and a slight external force causes the shaft to swing from the root of the shaft.

In particular, in a small variable resistor, the dimensions of the seat 2 and the resin substrate 9 are smaller than the axial length and diameter of the rotary shaft 1, so that the vertical support force of the rotary shaft is inevitably weak. I don't get.

That is, the inner diameter Φ1 of the inner surface of the cylindrical bearing portion is designed to be slightly larger than the diameter Φ2 of the rotary shaft so that the shaft can be inserted smoothly due to the limit of design accuracy.

Further, the height h of the peripheral wall of the bearing 4 is as low as 1 mm or less, and the vertical support of the inner surface 12 of the peripheral wall of the bearing 4 is not sufficient.

Further, as described above, the vertical support of the rotary shaft 1 is only by pressure contact by the elastic force of the slider 11, and when the rotary shaft 1 is pushed onto the receiving seat 2, it is slightly moved.

Therefore, in the conventional variable resistor 15, the rotary shaft 1 is wobbled laterally.

In the case of a small variable resistor having a long rotating shaft, the wobbling of the tip becomes large.

In this respect, the wobbling movement of the knobs attached to the rotary shaft is a disadvantage for the user as compared with a defective product, and therefore sufficient measures must be taken.

On the other hand, on the other hand, electric appliances such as video and audio, toys for radio control, and the like are becoming smaller and higher in performance, and accordingly, smaller variable resistors having a rotating shaft are required. Has been done.

As described above, the smaller the size of the rotary shaft, the smaller the vertical supporting force of the rotary shaft is structurally weakened. Therefore, the measures against wobbling of the rotary shaft are miniaturization and two-sided antithesis. I was presenting.

The present invention has been made in view of the above circumstances, and while supporting downsizing of the variable resistor, the vertical supporting force of the rotary shaft is significantly increased as compared with the conventional one, and the wobbling of the rotary shaft is increased. The present invention provides a variable resistor having a structure that prevents the above.

[0019]

[Means for Solving the Problems]

 The present invention provides a rotary shaft, a seat that supports the rotary shaft, a slider provided at one end of the rotary shaft, a resin substrate on which lead terminals are disposed, and a horseshoe baked on the resin substrate. A variable resistor structure having a carbon film resistor in a shape, wherein cutout groove portions are provided at two to twelve places on a peripheral wall of a cylindrical bearing portion of the seat that fits the rotary shaft and axially supports the rotary shaft. The inner surface of the bearing portion is provided with a taper whose inner diameter is gradually narrowed toward the opening on the protruding side of the rotating shaft, and the inner diameter of the opening peripheral edge of the protruding portion of the rotating shaft is smaller than the diameter of the abutting rotary shaft. In addition, by providing a variable resistor structure, the notch groove portions are provided at two to twelve places on the cylindrical bearing portion peripheral wall of the seat that fits the rotary shaft and axially supports the rotary shaft. Of the bearing By providing a variable resistor vessel structure characterized in that a protrusion for pressing the rotating shaft on the inner surface of the rolling shaft protruding side openings, is intended to accomplish the above object.

[0020]

[Action]

 In the present invention, the peripheral wall of the cylindrical bearing portion is divided into 2 to 12 by the notched groove portions at 2 to 12 places, and each peripheral wall functions as a leaf spring by the elasticity of the plastic material or the metal material.

Further, the taper provided on the inner surface of the bearing portion in the variable resistor structure according to claim 1 is provided so that the inner diameter gradually narrows toward the opening on the protruding side of the rotation shaft, and the inner diameter of the peripheral edge of the fitting side. Since the diameter is smaller than the diameter of the abutting rotary shaft, the rotary shaft is fitted and inserted against the elasticity of the peripheral wall, and after the insertion, is constantly pressed toward the axial center by the elasticity of the peripheral walls.

Therefore, the rotary shaft is axially supported perpendicularly to the seat while only being fitted into the bearing.

Further, in the variable resistor structure according to the second aspect, the protrusion provided on the inner surface of the rotary shaft projecting side opening of the bearing is such that the rotary shaft fitted by the elasticity of each peripheral wall always faces the axial center. Acts to press.

[0024]

【Example】

 Embodiments of a variable resistor according to the present invention will be described in detail below with reference to the drawings. It should be noted that the portions having the same shape and function as those of the above-mentioned conventional example are indicated by the same reference numerals.

FIG. 1 is an exploded perspective view for explaining the configuration of a variable resistor 20 according to claim 1 of the present invention. 2A is a vertical cross-sectional view taken along the line AB in FIG. 1 of the seat of the variable resistor 20, and FIG. 2B shows a slider and a resin by inserting a rotary shaft into the seat. It is a longitudinal cross-sectional view of the state which combined the board | substrate.

1 and 2, the variable resistor 20 includes a rotating shaft 21, a seat 22 that axially supports the rotating shaft 21, and a slider 11 attached to one end of the rotating shaft. The resin substrate 31 on which the lead terminals 23 are arranged and the horseshoe-shaped carbon film resistor 10 baked on the resin substrate 31 are further provided. Notches 27 are provided at four locations on the peripheral wall 26 of the cylindrical bearing portion 24 of the seat 22, and the inner surface 28 of the bearing portion is provided with a taper Θ whose inner diameter is gradually narrowed toward the opening 29 on the protruding side of the rotary shaft. The inner diameter Φ1 ′ of the rotary shaft protruding side opening peripheral edge 30 of the portion 24 is smaller than the diameter Φ2 ′ of the rotating shaft with which it abuts.

The rotary shaft 21 and the seat 22 may be made of metal or synthetic resin (for example, PBT, PET, PPS), but the dimensional accuracy of mass production and miniaturization, and the bearing portion 24 as described later. Considering that the elasticity of the peripheral wall 26 is used, it is preferable to use a synthetic resin that can be molded by injection molding.

The slider 11 is the same as the conventional one, and a circular metal plate having an elasticity of several millimeters is partially processed into a ring shape (see FIG. 1) and is slid while being urged by the carbon film resistor 10. It has a bent shape so as to raise the contact portion 32 so as to move, and is locked to one end of the rotary shaft 21.

Further, the carbon film resistor 10 is also the same as the conventional one, and is formed by baking a horseshoe-shaped carbon film on a resin substrate 31 such as Bakelite. A silver wiring pattern 33 is formed as a lead-in wiring from the end of the carbon film resistor 10 and is connected to the three lead terminals 23.

In this embodiment, metal washer 36 having projecting pieces 35 at four corners is used as a locking means for assembling the rotary shaft 21, the seat 22, and the resin substrate 31 to form the variable resistor 20. The tips of the projection pieces are internally folded and locked in the recesses 37 at the four corners of the seat 22.

Next, the axial stop structure of the rotary shaft 21, particularly the vertical support force of the seat 22 will be described in detail.

As is apparent from FIG. 1, in the present embodiment, the peripheral wall 26 (the height h ′ of the cylindrical bearing portion 24 of the receiving seat 22 that inserts the rotary shaft 21 and axially supports the rotary shaft 21 is slightly larger than that of the prior art). Notch groove portions 27 are provided at equal intervals at four places.

The notch groove portion 27 divides the peripheral wall 26 of the bearing portion 24 into four parts, and elastic displacements of the peripheral wall 26 of the shaft receiving portion 24 to the axial center side of the fitting insertion hole and to the outside of the fitting insertion hole (indicated by the arrow in (A) of FIG. 2). The displacement X) is made possible. At this time, the bottom 25 of the notch groove is cut in a circular shape to avoid concentration of stress during elastic displacement.

Further, the inner surface 28 of the bearing portion is provided with a taper Θ whose inner diameter is gradually narrowed toward the opening 29 on the protruding side of the rotating shaft. However, it is assumed that the peripheral surface 40 of the fitting hole inside the receiving seat 22 is parallel, its inner diameter Φ3 is slightly larger than Φ2 ′, and the rotary shaft 21 can rotate smoothly there.

Therefore, as shown in FIG. 2B, the root portion 38 of the rotary shaft 21 having a diameter of Φ 2 ′ is fitted into the fitting hole 39, and the rotation shaft protruding side opening peripheral edge 30 of the bearing portion 24 is formed. When fitted, since the design is such that Φ1 ′ <Φ2 ′, the rotary shaft 21 is fitted while being pushed out while resisting the elastic force of the peripheral wall 26, and the reaction of each peripheral wall 26 as a reaction thereof. The elastic force constantly pushes toward the axis.

The pressing from the peripheral walls 26 on four sides serves as a vertical supporting force, and prevents the rotary shaft 21 from wobbling left and right.

Next, the structure of the variable resistor according to claim 2 of the present invention will be described in detail with reference to FIG. Incidentally, the same parts as those in the above-mentioned embodiment are indicated by the same reference numerals.

FIG. 3A is a vertical cross-sectional view of the seat 42 of the variable resistor 41 according to claim 2, and FIG. 3B is a perspective view of the slider 11 in which the rotary shaft 21 is inserted into the seat 42. 3 is a vertical cross-sectional view of a state in which a resin substrate 31 and a resin substrate 31 are combined.

In FIG. 3A, the variable resistor 41 is replaced with the taper Θ provided on the inner surface 28 of the bearing portion of the seat 22 of the above-mentioned claim 1, and the inner surface 28 of the bearing portion 28 of the opening 29 of the rotary shaft protruding side is replaced with the taper Θ. The variable resistor 20 has the same structure as the variable resistor 20 according to the first aspect, except that the protrusion 43 is provided in the structure.

Although the shape of the projection 43 is not particularly specified, it is important to take care so that the projection 43 is not locked when the rotary shaft 21 is fitted and inserted.

When the rotary shaft 21 is fitted into the fitting hole 39, as shown in FIG. 3B, the root portion 38 of the rotary shaft 21 resists the protrusion 43 against the elastic force of each peripheral wall 26. As it pushes outwards and spreads out, it is constantly pushed toward the axis as a reaction.

That is, the provision of the projection 43 on the inner surface 28 of the bearing portion provides a vertical supporting force similar to that provided with the taper Θ in claim 1.

In addition, as a reminder, the substantial inner diameter Φ1 ″ of the rotating shaft protruding side opening 29 in the bearing portion 44 of the seat 42, which corresponds to the protruding portion 43, is substantially equal to the diameter Φ2 ′ of the rotating shaft. Needs to be designed smaller than.

It is to be noted that the gist of the present invention is to utilize the elastic force of the peripheral wall by providing a notch groove in the peripheral wall of the bearing portion of the seat into which the rotary shaft is inserted and a taper or protrusion on the inner surface of the bearing portion. Therefore, the structure of the seat other than the bearing and the shape and material of the other components are not limited to the present embodiment.

Further, in the present embodiment, there are four notch grooves, but it is needless to say that two or twelve notches are also possible. It is considered that the range of 2 to 12 places is desirable because it may cause problems in durability and the like.

[0046]

[Effect of device]

 Since the variable resistor structure according to the present invention is configured as described above, it has the effects described below.

(1) The vertical supporting force of the rotary shaft is remarkably improved, and the wobbling of the rotary shaft is prevented, which is an excellent effect.

(2) It has an excellent effect of being able to cope with miniaturization of a variable resistor of a type having a rotating shaft.

[Brief description of drawings]

FIG. 1 is an exploded perspective view illustrating a configuration of a variable resistor according to the present invention.

FIG. 2A is a vertical cross-sectional view taken along the line AB in FIG. 1 of the seat of the variable resistor, and FIG. 2B shows the slider and the resin substrate by inserting the rotary shaft into the seat. It is a longitudinal cross-sectional view of the state which combined.

3A is a vertical sectional view of a seat of the variable resistor according to claim 2, and FIG. 3B is a state in which a rotary shaft is fitted in the seat and a slider and a resin substrate are combined. FIG.

FIG. 4 is a partial cross-sectional view showing a structural example of a conventional small variable resistor having a general rotating shaft.

[Explanation of symbols]

1, 21 Rotating shafts 2, 22, 42 Seat 3 Fitting holes 4, 24, 44 Bearing part 5 Collar part 6 End surface 7 Protrusion 8 Hole 9, 31 Resin substrate 10 Carbon film resistor 11 Slider 12 Circumferential wall inner surface 13 Top of flange 14 Resistive substrate 15, 20, 41 Variable resistor 23 Lead terminal 25 Bottom of notch groove 26 Peripheral wall 27 Notch groove 28 Inner surface of bearing part 29 Rotating shaft protruding side opening 30 Rotating shaft protruding side opening peripheral edge 32 Contact point 33 Wiring pattern 35 Projection piece 36 Metal washer 37 Cavity 38 Root 39 Fitting hole 40 Fitting hole peripheral surface on the inner side of the seat 43 Protrusion X displacement Θ Taper Φ1 Inner diameter of bearing surface Φ1 ′ Inner diameter of rotation shaft protruding side opening Φ1 ″ Substantial inner diameter Φ2, Φ2 ′, which corresponds to the protrusion of the rotation shaft protruding side opening Φ3 Rotation shaft diameter Φ3 Inner diameter h, h ′ of the fitting insertion hole peripheral surface inside the seat Height of bearing peripheral wall

Claims (2)

[Scope of utility model registration request] 1. A rotary shaft, a seat for axially supporting the rotary shaft, and a slider provided at one end of the rotary shaft,
In a variable resistor structure having a resin substrate on which lead terminals are arranged and a horseshoe-shaped carbon film resistor baked on the resin substrate, a cylinder of the seat for inserting the rotary shaft and pivotally supporting the rotary shaft. Notch groove portions are provided at two to twelve places on the peripheral wall of the shaft-shaped bearing portion, and a taper is provided on the inner surface of the bearing portion, the inner diameter of which gradually narrows toward the opening on the protruding side of the rotary shaft,
A variable resistor structure, wherein an inner diameter of a peripheral edge of an opening of a bearing portion on a protruding side of a rotary shaft is smaller than a diameter of the rotary shaft with which the bearing abuts. 2. A rotary shaft, a seat for axially supporting the rotary shaft, and a slider provided at one end of the rotary shaft,
In a variable resistor structure having a resin substrate on which lead terminals are arranged and a horseshoe-shaped carbon film resistor baked on the resin substrate, a cylinder of the seat for inserting the rotary shaft and pivotally supporting the rotary shaft. A variable resistor structure, characterized in that notch grooves are provided at two to twelve places on the peripheral wall of the shaft bearing portion, and protrusions for pressing the rotary shaft are provided on the inner surface of the opening on the protruding side of the rotary shaft of the bearing portion.