JP3813691B2 - Potentiometer drive spring mounting structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rotary potentiometer that is attached to an outer surface of a housing, for example, and has a structure in which a rotating shaft led out to the outer surface is inserted and rotated by the rotating shaft.
[0002]
[Prior art]
A conventional structure of this type of potentiometer is shown in FIG. FIG. 5 shows a state in which the potentiometer is attached to the housing.
A metal bearing 12 is inserted and attached to the bottom surface of the resin case 11 whose upper surface side is open, and the resistor substrate 14 having the hole 13 is positioned in the hole 13 so that the case 12 is positioned in the case 11. The housing is fixed. The resistance substrate 14 has a required pattern formed on an insulating substrate and is not shown in the drawing in this example, but there are three sets of arc-shaped resistors and current collectors, on the circumference, etc. It is formed at angular intervals. In the figure, reference numeral 15 denotes a lead wire.
[0003]
A slider 16 that is in sliding contact with the resistance substrate 14 is attached to a rotating body 17. As shown in FIG. 6, the rotating body 17 made of a resin material has a disk shape having a mounting hole 18 in the center, and three sliders 16 are fixed to one plate surface at an equiangular interval. Installed.
The rotating body 17 is attached and fixed to a rotating shaft via a drive spring 21 made of a leaf spring material. As shown in FIG. 7, the drive spring 21 has a base portion 23 in which an oval shaft hole 22 is formed and a plurality of elastic arm portions 24 extending radially from the base portion 23. The portion 24 is bent with respect to the base portion 23 and is raised obliquely. In this example, three elastic arm portions 24 are provided to form a tripod, and three claws 25 projecting in three directions are formed at the ends of the elastic arm portions 24, respectively. The claws 25 are folded back in the direction opposite to the inclination direction of the elastic arm portion 24 as shown in the figure. A plurality of kerfs 26 for press-fitting are formed in the inner edge of the shaft hole 22.
[0004]
On the plate surface opposite to the plate surface on which the slider 16 of the rotating body 17 is attached, as shown in FIG. 6, a U-shaped bank on which each elastic arm portion 24 of the drive spring 21 is locked. Three 27 are provided at equiangular intervals.
Next, attachment of the potentiometer 28 having the above configuration to the housing will be described. In FIG. 5, reference numeral 31 denotes a housing that accommodates the detected movable part, and 32 denotes a rotating shaft that operates in conjunction with the movable part. The rotating shaft 32 is led out to the outer surface 34 of the housing 31 through a hole 33 formed in the housing 31. In the mounting structure as shown in FIG. 5, for example, in an automobile, a rotating shaft that rotates in conjunction with opening and closing of the throttle valve is led out of the housing, and the rotating shaft depends on the opening of the throttle valve. This is used when a potentiometer is installed to obtain a high output.
[0005]
First, the case 11 holding the resistance substrate 14 is attached to the housing 31 with the bottom surface being in contact with the outer surface 34 of the housing 31. Although not shown in the drawing, the attachment is performed by screwing. At this time, the rotary shaft 32 is positioned at the axial center position in the bearing 12.
Next, the rotating body assembly 35 shown in FIG. 6 is inserted into the cylindrical portion 12a whose mounting hole 18 protrudes from the bottom surface of the case 11 of the bearing 12, and the plate surface on which the bank 27 is provided is the outside. Thus, it is rotatably mounted around the cylindrical portion 12a of the bearing 12.
[0006]
And the drive spring 21 is attached between the rotating shaft 32 and the rotary body 17, and attachment is completed. At this time, the rotary shaft 32 is press-fitted into the shaft hole 22 of the drive spring 21, whereby the base 23 of the drive spring 21 is locked to the rotary shaft 32. On the other hand, the tip of each elastic arm portion 24 is press-fitted into each U-shaped bank 27 of the rotating body 17, and the claw 25 is deformed and pressed to be locked to the bank 27. In this state, the rotating body assembly 35 is urged toward the resistance board 14 by the drive spring 21, that is, each slider 16 is elastically contacted with the resistance board 14.
[0007]
In the potentiometer 28 mounted as described above, the rotation of the rotating shaft 32 is transmitted to the rotating body 17 by the drive spring 21 and the rotating body assembly 35 rotates, and each slider 16 and the corresponding resistor are gathered together. By making sliding contact with the electric body, an output corresponding to the rotation angle can be obtained. In addition, by having this drive spring 21, it is possible to absorb the vertical movement and undulation rotation of the rotating shaft 32, that is, the structure in which the play of the rotating shaft 32 does not affect the rotating body 17.
[0008]
[Problems to be solved by the invention]
By the way, in the structure for attaching the drive spring 21 to the rotating body 17 in the conventional potentiometer 28 described above, the tip of the elastic arm portion 24 on which the claw 25 is formed is simply press-fitted into the U-shaped bank 27. Therefore, there is a drawback that the drive spring 21 is easily detached from the rotating body 17.
[0009]
An object of the present invention is to provide a drive spring mounting structure that solves the conventional drawbacks and prevents the drive spring from falling off the rotating body.
[0010]
[Means for Solving the Problems]
According to the present invention, the rotating body having the slider that is in sliding contact with the resistance board mounted on one surface is urged toward the resistance board side by the drive spring locked to the rotation shaft and is rotated. The drive spring in the potentiometer is composed of a base portion with a shaft hole into which the rotation shaft is press-fitted and a plurality of elastic arm portions that extend radially from the base portion and have claws protruding on both sides of the tip. The tip of the arm portion is fitted between a pair of banks each having a hook inside each other formed on the other surface of the rotating body, so that the driving spring is attached to the rotating body by being prevented from coming off by the claw and the hook. Structured.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the drawings. Note that portions corresponding to those in FIGS. 5 to 7 are denoted by the same reference numerals, and description thereof is omitted.
FIG. 1 shows an embodiment of the present invention in which a driving spring is attached to a rotating body, and FIGS. 2 and 3 show the configurations of the rotating body 41 and the driving spring 42, respectively. First, the configuration of each part will be described with reference to FIGS.
[0012]
In this example, a pair of banks 43 arranged in the circumferential direction are provided at three locations on the circumference at equal angular intervals on the plate surface opposite to the plate surface to which the slider 16 of the rotating body 41 is attached. . Each pair of banks 43 is opposed to each other at a predetermined interval, and a slightly protruding ridge 44 is formed facing each other inside each other. In FIG. 2, 45 indicates a through hole through which a pin of the molding die is passed for forming the flange 44.
[0013]
On the other hand, as shown in FIG. 3, the drive spring 42 is formed by projecting square claws 46 on both sides in the vicinity of the distal ends of the elastic arm portions 24 extending from the base 23. The elastic arm portion 24 is bent in the direction opposite to the inclination direction. A portion of each elastic arm 24 that slightly protrudes from the portion where the pair of claws 46 is provided is folded as shown in the figure.
[0014]
The drive spring 42 is attached to the rotating body 41 by fitting each end of the elastic arm portion 24 between a pair of corresponding banks 43 of the rotating body 41. At this time, the pair of claws 46 are paired with a pair of hooks 44. And is elastically restored and accommodated between the pair of banks 43. As a result, the claw 46 is stopped at the tip of each elastic arm portion 24 by the hook 44 and is prevented from coming off. The tip of each elastic arm portion 24 is movable in a space surrounded by a pair of banks 43 and ridges 44, and can absorb backlash of the rotating shaft.
[0015]
FIG. 4 shows an example of a potentiometer provided with the rotating body 41 and the drive spring 42 described above, and a state in which the potentiometer is attached to the housing 31. In this example, a cover 47 is attached to the case 11, and the outer periphery of the rotating body 41 is pressed by the cover 47, that is, the drive spring 42 is prevented from coming off from the rotating body 41, and the rotating body 41 is also removed from the case 11. It has been secured.
[0016]
【The invention's effect】
As described above, according to the present invention, since the claw is caught on the ridge formed on the rotating body, the drive spring can be prevented from coming off from the rotating body and falling off.
Therefore, if this mounting structure is adopted, a potentiometer with excellent reliability can be obtained.
[Brief description of the drawings]
FIG. 1A is a plan view showing an embodiment of the present invention, B is a sectional view thereof, and C is a bottom view thereof.
2A is a plan view of a rotating body to which the slider in FIG. 1 is attached, FIG. 2B is a cross-sectional view thereof, and C is a bottom view thereof.
3A is a plan view of the drive spring in FIG. 1, and B is a cross-sectional view thereof. FIG.
4A is a plan view showing an example of a potentiometer adopting the attachment structure of FIG. 1, and B is a cross-sectional view showing a state where A is attached to a housing. FIG.
FIG. 5 is a cross-sectional view showing a drive spring mounting structure of a conventional potentiometer.
6A is a plan view of a rotating body to which the slider in FIG. 5 is attached, FIG. 6B is a sectional view thereof, and FIG.
7A is a plan view of the drive spring in FIG. 5, and B is a cross-sectional view thereof. FIG.

Claims (1)

The above-mentioned drive in a potentiometer having a structure in which a rotating body having a slider slidably contacting the resistance board mounted on one surface is urged toward the resistance board by a driving spring locked to a rotating shaft and rotated. A structure for attaching a spring to the rotating body,
The drive spring is composed of a base portion formed with a shaft hole into which the rotation shaft is press-fitted, and a plurality of elastic arm portions extending radially from the base portion and having claws protruding on both sides of the tip.
The drive springs are prevented from coming off by the claws and the hooks by the ends of the elastic arms being fitted between a pair of banks formed on the other surface of the rotating body and having hooks inside each other. A drive spring mounting structure for a potentiometer, characterized in that is attached to the rotating body.

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