CN102803903A - Potentiometer - Google Patents

Abstract

The present invention provides a potentiometer having, within a housing (20), a substrate (50) having resistance patterns (53, 54) formed thereon, a rotating component (40), and a torsion spring (35). The rotating component (40) is fixed with a sliding component (34), and a rotating shaft (33) passing through the torsion spring (35) and connected to the rotating component (40) protrudes from the housing (20). The rotating component (40) has a pair of spring guides (42, 43) surrounding the torsion spring (35) and forming an arc along the outer diameter section of the torsion spring. The two ends (35a, 35b) of the torsion spring (35) extending radially into contact with the two circumferential end faces (43a, 43b) of the spring guide (43) and the two circumferential end faces of the spring support portion (25) protruding from the inner circumferential surface of the housing (20). The two end faces (43a, 43b) of the spring guide (43) and the two end faces (25a, 25b) of the spring support portion (25) are in point contact with the two ends (35a, 35b) of the torsion spring (35). In a potentiometer equipped with an automatic return mechanism, loosening of the rotating shaft in the neutral position can be prevented.

Description

Potentiometer

technical field

The present invention relates to a potentiometer which is used for position detection of various devices and is equipped with an automatic return mechanism of a rotating shaft.

Background technique

FIG. 1 is an exploded perspective view showing a potentiometer described in Patent Document 1, which is a conventional example of such a potentiometer.

In FIG. 1 , reference numeral 11 is a slide member support portion, and a protrusion 11 b protrudes from a central portion of a bottom plate 11 a thereof, and a shaft 11 c is formed upward and downward from the central portion. A pair of restriction walls 11d and 11e are erected on the outer periphery of the bottom plate 11a, and a predetermined angle is maintained therebetween.

Reference numeral 12 is a torsion spring, which has a winding protruding portion 11b and a coiled multi-layered portion 12a, and has an upper bending portion 12b and a lower bending portion 12c at the release end, and reference numeral 13 is a storage slide member support The shell of the part 11, the shell 13 has a cutout part 13a, and the side edges of the cutout part 13a are spring supporting parts 13b, 13c.

Reference numeral 14 is a sliding member fixed to the lower surface of the sliding member support portion 11 , and reference numeral 15 is an insulating substrate fixed to the open surface of the case 13 . On the upper surface of the insulating substrate 15, a resistive pattern 15a through which the sliding member 14 slides is formed.

The upper shaft 11c of the sliding member supporting portion 11 is supported by the hole 13d of the case 13 , and the lower shaft 11c is supported by the hole 15b of the insulating substrate 15 . As shown in Figure 2, the upper bending part 12b of the torsion spring 12 is elastically pressed and locked on the spring support part 13b and the limiting wall 11d, and the lower bending part 12c is elastically pressed and locked on the spring supporting part 13c and the limiting wall 11e.

In this potentiometer, when the shaft 11c is rotated counterclockwise from the stationary state in FIG. 2 , as shown in FIG. The lower bent portion 12c of the torsion spring 12 is pressed counterclockwise, and the upper bent portion 12b of the torsion spring 12 is locked to the spring support portion 13b of the case 13, so that the restricting wall 11d rotates counterclockwise. At this time, the sliding member 14 slides counterclockwise on the resistance pattern 15a, and a desired output signal is obtained by changing the resistance value.

Here, if the rotational force of the shaft 11c is removed, the elastic restoring force of the torsion spring 12 presses the lower bent portion 12c in the clockwise direction, so that the sliding member supporting portion 11 and the torsion spring 12 return to the original stationary state shown in FIG. 2 . state.

Similarly, when the shaft 11c rotates clockwise from the stationary state in FIG. The restricting wall 11e rotates clockwise while the portion 12c remains locked to the spring receiving portion 13c of the case 13 . Thus, by sliding the slide member 14 counterclockwise on the resistance pattern 15a, a desired output signal is obtained by utilizing a change in the resistance value.

Here, if the rotational force of the shaft 11c is removed, the lower bent portion 12c is pushed clockwise by the elastic restoring force of the torsion spring 12, and the sliding member supporting portion 11 and the torsion spring 12 return to the original rest position in FIG. 2 . state.

Similarly, when the shaft 11c is rotated clockwise from the stationary state in FIG. The restricting wall 11e rotates clockwise while the portion 12c remains locked to the spring receiving portion 13c of the case 13 . Thus, by sliding the slide member 14 clockwise on the resistance pattern 15a, a desired output signal is obtained.

prior art literature

Patent Document 1: (Japanese) Utility Model Registration No. 2533523

Contents of the invention

The technical problem to be solved by the invention

However, in the potentiometer of the above-mentioned structure, since the end faces of the restricting walls 11d and 11e provided on the sliding member supporting part 11 and the end faces of the spring supporting parts 13b and 13c provided on the case 13 are formed as planes, twisting The contact between the upper bent portion 12b and the lower bent portion 12c of the spring 12 and these restricting walls 11d, 11e, and spring support portions 13b, 13c is basically line contact.

On the other hand, when in the static state (neutral position) such as FIG. 2, the end faces of the limiting walls 11d, 11e and the end faces of the spring support portions 13b, 13c are not reliably aligned due to dimensional tolerances, that is, a pair of The state where the interval between the restriction walls 11d and 11e is larger than the interval between the pair of spring support portions 13b and 13c, or the opposite state.

When the distance between the pair of restricting walls 11d and 11e is larger than the distance between the pair of spring support parts 13b and 13c, the upper bent part 12b and the lower bent part 12c of the torsion spring 12 are in the neutral position in FIG. The position is only in elastic contact with the spring support portions 13b, 13c, and not in contact with the restriction walls 11d, 11e. In addition, on the contrary, the distance between the pair of restriction walls 11d, 11e is smaller than that of the pair of spring support portions 13b. , 13c, the upper bent portion 12b and the lower bent portion 12c are in elastic contact only with the restricting walls 11d, 11e, but not with the spring support portions 13b, 13c.

Since such a state is a structure in which the upper bending portion 12b and the lower bending portion 12c are in line contact with the restricting walls 11d, 11e, and the spring support portions 13b, 13c, the upper bending portion 12b and the lower bending portion are limited due to the line contact. The shape of the extending direction of the portion 12c, that is, a problem of limiting deflection arises. If such a state occurs, in the neutral position, the rotation of the shaft 11c is not completely restricted and looseness occurs, and such a problem lowers the detection accuracy.

Technical solutions for solving technical problems

The present invention has been made in view of the above problems, and an object of the present invention is to provide a potentiometer that does not cause backlash on a rotating shaft even when the potentiometer is in a neutral position, and has good detection accuracy.

According to this invention, housed in the case are: a substrate on which a resistive pattern is formed, a substrate on which a resistive pattern is formed, a rotating member, and a torsion spring. The torsion spring and the rotating shaft combined with the rotating part protrude from the housing, wherein the rotating part has a pair of spring guides that surround the torsion spring and are arc-shaped along the outer diameter section of the torsion spring. The two ends of the guide are in elastic contact with the circumferential end faces of one of the pair of spring guides and the circumferential end faces of the spring support part protruding from the inner peripheral surface of the shell, and the circumferential end faces of one spring guide The circumferential end surfaces of the spring support portion and the spring support portion are shaped to be in point contact with both end portions of the torsion spring, respectively.

The effect of the invention

In this invention, both ends of the torsion spring that automatically returns the rotating shaft are configured to be in point contact with both end faces of the spring guide of the rotating member and both end faces of the spring support portion of the housing. Therefore, when it is in the neutral position, even if the two ends of the spring guide are not aligned with the two ends of the spring support due to dimensional tolerances, unlike the existing line contact structure, since there is no restriction on the shape of the two ends of the torsion spring, The bending can be expected, that is, a state in which both ends of the torsion spring are in good elastic contact with both the spring guide of the rotating member and the spring support portion of the case can be obtained by bending the both ends. Therefore, according to the present invention, it is possible to prevent looseness of the rotating member and the rotating shaft at the neutral position, and it is possible to obtain a potentiometer with high detection accuracy by this means.

Description of drawings

FIG. 1 is an exploded perspective view of a conventional potentiometer.

FIG. 2 is a cross-sectional view of the potentiometer shown in FIG. 1 in a static state (neutral position).

Fig. 3 is a cross-sectional view of the operating state of the potentiometer shown in Fig. 1 .

Fig. 4A is a perspective view showing an example of the potentiometer of the present invention, and Fig. 4B is a front view thereof.

5A is a sectional view taken along line C-C of FIG. 4B , and FIG. 5B is a sectional view taken along line D-D of FIG. 4B .

FIG. 6 is an exploded perspective view of the potentiometer shown in FIG. 4A .

Fig. 7 is a diagram for explaining attachment of a sliding member to a rotating member.

FIG. 8A is a cross-sectional view when the rotating shaft is in a neutral position, and FIG. 8B is an enlarged view of this part.

FIG. 9A is a cross-sectional view of a state in which the rotation shaft rotates counterclockwise, and FIG. 9B is a cross-sectional view of a state in which the rotation shaft rotates in a clockwise direction.

Detailed ways

Embodiments of the invention will be described through examples with reference to the drawings.

4A and 4B show the appearance of an embodiment of the potentiometer of the present invention, and FIGS. 5A and 5B show its cross-sectional structure. In addition, FIG. 6 shows disassembled parts.

The case 20 has a cylindrical main body 21, on the back side of the main body 21, a square plate portion 22 protrudes from the outer peripheral surface thereof, and on the front side of the main body 21, a large flange-shaped portion protrudes from the outer peripheral surface thereof in opposite directions. A pair of mounting parts 23. In addition, a stepped cylindrical portion 24 protrudes from the front surface of the main body 21 .

The bearing 31 is accommodated in the cylindrical part 24 of the case 20, and the metal sleeve 32 is accommodated and arrange|positioned in each sleeve hole 23a of a pair of attachment part 23. As shown in FIG. The housing 20 and the bearing 31 are respectively made of synthetic resin. In this embodiment, the bearing 31 and the sleeve 32 are insert-molded in the housing 20 . Furthermore, although both the case 20 and the bearing 31 are made of synthetic resin, the case 20 uses a resin that is highly rigid and good in flame retardancy, and the bearing 31 uses a resin that is good in wear resistance.

The rotating member 40 has a plate portion 41 and a pair of spring guides 42 and 43 protruding from one surface of the plate portion 41, and is made of synthetic resin. The cross-sections of the pair of spring guides 42 and 43 are respectively arc-shaped, and the arcs are located on the same circumference. The plate portion 41 has a disk shape, and a portion located on the outer peripheral side of one spring guide 43 has a cutout shape.

The rotating shaft 33 is made of metal, has an elliptical portion 33a formed at one end, and a small-diameter shaft 33b protrudes from the front end surface of the elliptical portion 33a. The elliptical portion 33a of the rotating shaft 33 is fitted into the plate portion 41 of the rotating member 40 and integrally formed with the rotating member 40, and the rotating shaft 33 is located at the center of the arc formed with the spring guides 42, 43. In addition, a shaft 33 b formed on the front end surface of the elliptical portion 33 a protrudes from the back side of the plate portion 41 of the rotating member 40 .

The slide member 34 is attached to the back side of the plate portion 41 of the rotating member 40 . As shown in FIG. 7 , on the back surface of the plate portion 41 , a push nut pressing portion 44 , a heat caulking portion 45 and a guide portion 46 are protrudingly formed. The slide member 34 is made of springy metal, and has a push nut portion 34a, a caulking hole 34b, and a notch 34c. Press the push nut part 34a of the sliding part 34 into the push nut press-in part 44 of the rotating part 40, and make the heat riveting part 45 of the rotating part 40 pass through the riveting hole 34b, and install and fix the sliding part 34 on the rotating part 40 by heat riveting . In addition, the guide portion 46 of the rotating member 40 and the notch 34c of the slide member 34 corresponding to the guide portion 46 function as a guide when the slide member 34 is incorporated.

The torsion spring 35 passes through the rotating shaft 33 and is housed in the space inside the pair of spring guides 42 and 43 of the rotating member 40 . The pair of spring guides 42, 43 surrounds the torsion spring 35 along the outer diameter of the torsion spring 35, whereby the torsion spring 35 circumscribes the pair of spring guides 42, 43 and maintains this state.

The rotating shaft 33 passes through and is pivotally supported by the hole 31 a of the bearing 31 fitted into the case 20 . In the cylindrical portion 24 of the housing 20 , a lip seal 36 is disposed outside the bearing 31 , and a gasket 37 and an E-ring 38 for restricting movement of the lip seal 36 are disposed. The E-ring 38 is fitted into the E-ring insertion groove 33 c provided on the rotating shaft 33 . The front side of the housing 20 is sealed by a lip seal 36 .

The substrate 50 is attached to the rear opening of the main body 21 of the case 20 . The substrate 50 is composed of an annular portion 51 and a rectangular protruding portion 52 partially protruding from the outer periphery of the annular portion 51 . A pair of arc-shaped resistance patterns 53 and 54 are concentrically formed on the annular portion 51, and conductor patterns 55 to 57 are formed. connected, and reach the front end of the protruding portion 52 through the ring portion 51 . Resistor patterns 53 and 54 are formed by printing and firing a resin paste mixed with, for example, carbon particles, and conductive patterns 55 to 57 are formed by printing and firing silver paste.

Terminal insertion holes 58 passing through the substrate 50 are formed at the front ends of the respective conductor patterns 55 to 57 , and terminals 61 are crimped and attached to the terminal insertion holes 58 , respectively. In addition, in FIG. 6, the crimping part 61a of the terminal 61 has a crimped shape.

The substrate 50 is pressed into the main body 21 of the case 20 , and touches and is accommodated in the contact portion 21 a provided in the main body 21 . As a result, the slide member 34 attached to the rotary member 40 is brought into pressure contact with the resistance patterns 53 and 54 . In addition, an annular portion 47 surrounding the shaft 33 b and protrudingly formed on the back side of the plate portion 41 of the rotating member 40 is located in the opening 59 of the base plate 50 .

A cover 62 is also attached to the rear opening of the main body 21 of the case 20 . The cover 62 is fixed by heat caulking a heat caulking portion 21 b provided in the main body 21 of the case 20 . In the inner surface of the cover 62, a bearing hole 62a is formed which pivotally supports the shaft 33b formed at the front end of the rotary shaft 33, and the shaft 33b is pivotally supported by the bearing hole 62a.

As shown in FIGS. 5A and 5B , an adhesive 63 is applied and filled around a cover 62 attached to the case 20 , thereby sealing the back side of the case 20 . In addition, in this embodiment, inside the case 20, a space is provided at the portion where the terminal 61 is located, and as shown in FIG. Therefore, it is possible to securely fix the terminals 61 and prevent movement between the terminals 61 . In addition, if the terminal 61 is configured such that carbon steel is tin-plated, for example, growth of tin-plated whiskers (wiskers) can be prevented.

Next, with reference to FIGS. 8A and 8B , the positions and locking states of the both end portions 35 a and 35 b leading out in the radial direction of the torsion spring 35 in the housing 20 will be described.

8A and 8B show the state where the rotating shaft 33 is in the neutral position. The two ends 35a, 35b of the torsion spring 35 are in elastic contact with the circumferential end faces 43a, 43b of the spring guide 43 of the rotating member 40, and are in an arc shape. The circumferential end surfaces 25a, 25b of the spring support portion 25 protrudingly provided on the inner peripheral surface of the case 20 elastically contact each other.

Both end portions 35a, 35b of the torsion spring 35, both end surfaces 43a, 43b of the spring guide 43, and both end surfaces 25a, 25b of the spring support portion 25 are configured to be in contact by point contact. In this embodiment, the respective end surfaces of the end portions 35a, 35b of the torsion spring 35 are in point contact with the end surfaces 25a, 25b of the spring support portion 25, between the end portion 35a and the end surface 25a and between the end portion 35b and the end surface 25b. A wedge-shaped space expanding toward the center of the rotating member 40 is formed, respectively. On the other hand, the end surfaces 43a, 43b of the spring guide 43 are in point contact with the ends 35a, 35b of the torsion spring 35 at their inner peripheral corners, respectively, and between the end 35a and the end surface 43a and between the end 35b and the end surface 43b. A wedge-shaped space expanding toward the outer peripheral side of the rotating member 40 is formed therebetween.

Thus, since the both end surfaces 43a, 43b of the spring guide 43 and the two end surfaces 25a, 25b of the spring support portion 25 are shaped to be in point contact with the two end portions 35a, 35b of the torsion spring 35, respectively, the two ends of the torsion spring 35 The portions 35a, 35b are easily deflected. Therefore, when in a neutral state, even if the end faces 43a, 43b of the spring guide 43 are not aligned with the end faces 25a, 25b of the spring support portion 25 due to dimensional tolerances, etc., the torsion spring 35 is also used. The deflection of both ends 35a, 35b enables the ends 35a, 35b of the torsion spring 35 to be in good elastic contact with the spring guide 43 and the spring supporting portion 25 without causing looseness in the rotating member 40 and the rotating shaft 33 .

In addition, in this embodiment, in order to form a wedge-shaped space between the end portions 35a, 35b of the torsion spring 35, the two end surfaces 43a, 43b of the spring guide 43 and the two end surfaces 25a, 25b of the spring support portion 25 are provided with The desired inclination, that is, an inclined surface may be, for example, a curved surface.

Fig. 9A, Fig. 9B respectively represent the state that rotating shaft 33 is in anticlockwise direction and clockwise direction, and in Fig. 9A, the spring guide 43 of rotating member 40 squeezes the end 35a of torsion spring 35 and resists its elasticity, and In FIG. 9B, the spring guide 43 of the rotating member 40 presses the end portion 35b and resists its elasticity. The sliding member 34 slides on the resistance patterns 53 and 54 of the substrate 50 by the rotation of the rotating member 40 , and a desired output signal can be obtained through the terminal 61 . When the rotational force of the rotating shaft 33 is released, the rotating member 40 and the rotating shaft 33 are returned to their original neutral positions shown in FIG. 8A by the elastic restoring force of the torsion spring 35 .

As described above, according to the present embodiment, it is possible to prevent backlash of the rotation shaft 33 from occurring at the neutral position. In addition, since the torsion spring 35 is circumscribed and held by the pair of spring guides 42 and 43 of the rotating member 40, the axis of the spring is not inclined and unexpected deformation is not generated, so good rotation performance can be obtained.

In addition, this potentiometer is used to detect, for example, the depression amount of the accelerator pedal of an electric vehicle, a scooter, or the like.

Claims (3)

1. pot; In its shell, take in: the substrate, rotary part and the torsion spring that are formed with resistance pattern; Said rotary part is fixed with the slide unit that is slidingly connected with said resistance pattern; The turning axle that passes said torsion spring and combine with said rotary part is outstanding from said shell, said potentiometric being characterised in that

Said rotary part possesses the external diameter section that surrounds the said torsion spring of said torsion spring and edge and is circular-arc a pair of spring guiding,

The circumferential both ends of the surface of a spring guiding from the both ends of radially deriving of said torsion spring and said a pair of spring guiding and give prominence to the circumferential both ends of the surface Elastic Contact of the spring-loaded portion of the inner peripheral surface that is arranged at said shell,

The circumferential both ends of the surface of the circumferential both ends of the surface of said spring guiding and said spring-loaded portion are to carry out a shape that contacts with the both ends of said torsion spring respectively.

2. pot as claimed in claim 1 is characterized in that,

The front end separately at the both ends of said torsion spring and the circumferential both ends of the surface of said spring-loaded portion carry out contacting.

3. pot as claimed in claim 1 is characterized in that,

The all within it side corner sections of circumferential both ends of the surface of said spring guiding carry out contacting with the both ends of said torsion spring respectively.

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