JPH1151606A - Angle potentiometer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the angle potentiometer which is high in strength, easy and secure in fitting and waterproof properties, good in linearlity and precision, and more small-sized. SOLUTION: This potentiometer is equipped with a 1st bearing 14 which supports a rotary shaft 10 on the side of its tip 10a, a housing 2 into which the 1st bearing is inserted and which has a resistance body 23 and an electrode part 24 arranged on its inside surface, and a rear lid 3 provided with a 2nd bearing 19 supporting the other end 10j of the rotary shaft. The rotary shaft is provided with a 1st bearing, a brush holder 16a having a brush 26, a fixation part 16 for fixing the brush holder to the rotary shaft, and a 2nd bearing sequentially and the fixation part is provided with stoppers 17 and 18 which limit the rotation range of the rotary shaft. Further, a collar part 12 which is enabled to abut against a step 11 of the housing on its tip side is provided between the tip of the rotary shaft and the 1st bearing, a seal member 13 is provided between the tip of the rotary shaft and the 1st bearing, and a wire 30 is extended out of the housing side surface 32 in a waterproof state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an angle potentiometer used for construction machines and industrial machines and capable of detecting a rotation angle while a load is being applied to a rotating shaft.

[0002]

2. Description of the Related Art Conventionally, an angle potentiometer has been used as a device for measuring various rotation axes and swing angles.
An angle potentiometer is useful as a means for measuring an absolute angle from a reference point. A conventional general angle potentiometer 99 has a rotating shaft 10 as shown in FIG.
The angle detection is performed by taking out, as a voltage value, an output resistance value of the resistor 101 which is constituted by the brush 101 rotating together with 0, and the resistor 102 and the electrode portion 108 which are in contact with the brush 101, respectively.

In mounting such an angle potentiometer, the rotary shaft is rotatably supported by bearings 104 and 105 provided between the housing 103 and the rotary shaft 100 by fixing the angle potentiometer to the mounting member 5 on the body side with bolts 111. You. The resistance change of the resistor 102 provided on the bottom surface of the housing is determined by the lead wire 106 through the lead wire outlet 1.
07 to the body-side mounting member 5.

In such a conventional angle potentiometer, the shape of the resistor 102 is changed as shown in FIG. 8 so that the brush does not slide on the terminals of the resistor and the electrode.
The terminal portions 102a and 102 are located at positions away from the concentric circles of the sliding portion.
b, 108a are provided. For this reason, the diameters of the resistor 102 and the electrode portion 108 must be physically small, and it is difficult to improve the linearity of the detection angle with the same outer diameter. Therefore, a mechanical stopper mechanism for mechanically limiting the rotation angle may be provided so that the brush does not slide on the terminal portion. However, there is a problem that the axial length is further increased in order to provide a mechanical stopper mechanism.

Further, small rolling bearings 104 and 105 are used to support the rotating shaft 100 by the housing 103, so that a large load cannot be applied to the rotating shaft 100. When a large load is applied to the rotating shaft 100 in the axial direction or the radial direction, a large error may occur in the detection value due to deformation or the like, or the resistor 102, the brush 101, or the electrode 108 may be broken. Therefore, when the rotating body is heavy, or when the rotating shaft 10 of the angle potentiometer is
When a load is applied to zero, there is a problem that the rotation angle must be detected using a spring, an elastic joint, or the like so that the load is not directly applied to the rotating shaft.

[0006]

SUMMARY OF THE INVENTION
In Japanese Patent Application Laid-Open No. 6805, a large-diameter bearing is used, but in this case, there is a problem that the whole becomes larger by the size of the bearing. Further, in FIG. 9, the lead wire is structurally, and the rotation shaft 100 → the brush 101 →
Because of the arrangement of the resistor 102 and the electrode portion 108, the lead wire take-out portion 107 is led out to the side of the body-side mounting member 5 where there is no room for space when viewed from the front end side of the rotating shaft, and the wiring is reduced. Hard to do. Furthermore, since water does not have a waterproof structure, when water invades from the outside, there is a problem that the resistor 102, the electrode portion 108 and the like generate electrolytic corrosion (migration). Japanese Utility Model Laid-Open Publication No. 6-76805 also has a similar structure and has the same kind of problem.

An object of the present invention is to provide a mechanical stopper mechanism for mechanically restricting the rotation angle to increase the diameters of the resistor and the electrode portion as much as possible to improve the linearity, and to enable the rotation angle to be detected accurately. To provide a smaller angle potentiometer. Another object of the present invention is to provide an angle potentiometer which is free from damage even if a relatively large load acts on the rotating shaft, prevents water from entering from the outside of the angle potentiometer, and is simple and reliable in mounting.

[0008]

In the present invention, the rotating shaft, the first bearing rotatably supporting the rotating shaft, and the first bearing are inserted so that the tip of the rotating shaft projects outward. A housing provided with a central hole to be attached, a resistor and an electrode portion disposed on the inner surface concentrically with the central hole, a second bearing rotatably supporting the other end of the rotating shaft, And a rear lid that seals the housing with the bearing inserted therein. The rotating shaft has a first bearing, a brush holder having a brush that slides on a resistor and an electrode portion to change a resistance value, a fixing portion that fixes the brush holder to the rotating shaft, and a separate fixing portion. The above-described problem has been solved by providing an angle potentiometer provided with a stopper, which is disposed integrally with the body or integrally and restricts a rotation range of the rotating shaft, and a second bearing.

That is, since the resistor and the electrode are arranged on the tip side of the rotating shaft, the brush surface of the brush holder is directed toward the resistor and the electrode, and the brush holder fixing portion is arranged on the anti-resistor side. The clearance between the brush and the body and the electrode portion can be reduced, the space on the fixing portion side for fixing the brush holder can be increased, and the axial length can be shortened even if a stopper is provided. Further, it is easy to provide the direction of taking out the lead wires of the resistor and the electrode portion on the housing side. By providing the stopper, it is possible to prevent the brush from running on the resistor and the terminal portion of the electrode portion, and it is possible to dispose a resistor having a larger outer diameter.

[0010] Further, by providing a flange between the tip of the rotary shaft and the first bearing, the opposite end of which can contact the step of the housing, the pushing force in the thrust direction of the rotary shaft is reduced. The thrust load is not directly applied to the bearing since the bearing is received by the step portion of the housing.

Further, a seal member is provided between the tip of the rotating shaft and the first bearing so as to be in sliding contact with the inner surface of the center hole of the housing, so that the wiring of the resistor and the electrode portion can be waterproofed from the side surface on the housing side to the outside. By extending the cable, the degree of freedom of wiring to the outside is increased, and the waterproof performance is enhanced.

[0012]

An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view of an angle potentiometer according to one embodiment of the present invention, FIG. 2 is a partially enlarged view showing another embodiment in the vicinity of a flange of a rotary shaft shown in FIG.
FIG. 4 is an explanatory view of a resistor and an electrode portion of the present invention, FIG. 4 is a circuit diagram of detecting a resistor, FIG. 5 is an output diagram of the resistor, and FIG. FIG. 7 is a sectional view taken along line A-A of FIG. 1 showing another embodiment of the stopper of the present invention. In FIG. 1, an angle potentiometer 1 of the present invention has an outer shell composed of a housing 2 and a rear lid 3 and is assembled by mounting bolts 4 to form a single product.

The tip of the mounting bolt 4 is attached to the body-side mounting member 5.
The angle potentiometer 1 is fixed to the body-side mounting member 5 by bolts 6 using mounting holes (not shown) provided in the housing 2 or the rear lid 3.
(Not shown). 52 is an O-ring for sealing between the housing 2 and the rear lid 3. The rear lid 3 is positioned on the fuselage-side mounting member 5 by a spigot portion 7 formed at its outer diameter, and the rear part 7a of the rear lid is housed in a hole 8 of the fuselage-side mounting member.

On the inner end surface of the housing 2 of the angle potentiometer 1, a substrate 21 provided with a thin resistor 23 and an electrode portion 24 on the surface is fixed with an adhesive, a screw or the like with the back surface 27 in contact with the inner end surface of the housing. Have been. As shown in FIG. 3, the resistor 23 is formed in a ring shape in which a part thereof is missing.
Are formed in a ring shape concentric with the resistor 23,
Is formed of, for example, a conductive resin. Resistor terminals 50a and 50c are provided at both ends of the resistor 23 via the electrodes 23a, and an electrode terminal 50b extending from the electrode portion 24 is provided at a substantially intermediate position between the resistor terminals. As shown in FIG. 1, each terminal 50a, 50b, 50c is a rivet 2
8, connected to the lead wire 30 via the solder portion 29, and the lead wire is connected to the housing 2 via the rubber bush 31.
Is led out from the side surface of. A urethane resin 54 or the like is applied to the solder part 29, the lead wire 30, and the substrate part 33, or a hole 32 provided in the housing 2 is filled with a urethane resin or the like. The rubber bush 31 is used for the purpose of preventing the lead wire from breaking due to vibration or the like.

A rotary shaft 10 is provided to protrude from the housing 2. The rotary shaft 10 has an inner ring of the first bearing 14 inserted into the middle diameter portion 10 e and a stop 10 d of the rotary shaft and a stop such as a snap ring. The inner ring of the second bearing 19 is inserted and fixed to the end 10j while being held and fixed by the gold 15. An outer ring of the first bearing 14 is inserted into a shaft hole 2 b provided at an inner end of a center hole 2 a provided in the housing 2, and a second bearing 19 is provided in a housing provided in a bottom of the rear lid 3. Is inserted into a shaft hole 7b concentric with the center hole of the rotary shaft 10 to rotatably support the rotating shaft 10. When a tensile force is applied to the rotating shaft 10, the upper part 15 a of the stopper 15, the first bearing, the shaft hole 2
The rotating shaft is prevented from falling out of the housing by receiving a load at the end b. The center hole 2a, the rotating shaft 10, the resistor 23, and the electrode 24 are concentric.

The stopper 15 of the rotating shaft 10 and the second bearing 19
The fixed part 16 is formed between the resistor part 23 and the electrode part 24 side.
And a plate-shaped stopper member 17 formed along the axis.
Is provided. The brush holder 16a is fixed to the fixing portion 16.
As a result, a brush 26 that keeps a plane perpendicular to the rotation axis and makes contact with the resistor 23 and the electrode portion 24 to conduct the two is fixed by a rivet (not shown) or the like. A thin washer-shaped spacer 20 is provided between the fixing portion 16 and the second bearing 19 so that the distance L (related to the brush contact pressure) between the brush holder 16a and the substrate 21 can be adjusted. . The contact pressure between the brush 26 and the resistor 23 or the electrode portion 24 is determined by considering the processing dimension of each component and the gap L.
(For example, a specified dimension of about ± 0.1 mm).

As shown in FIG. 6, a plate-like projection 18 is formed in a part of the inner cavity of the rear lid 3 from the outside toward the center.
The stopper member 17 provided on the fixed portion 16 can be brought into contact with the stopper member, and the projecting portion and the stopper member constitute a stopper to limit the rotation angle of the rotating shaft. 6, the overhanging portion 18 has one wing and the stopper member 17 has two wings. FIG. 7 shows the overhanging portion 18 having two wings and the stopper member 17 has one wing. The case where each is limited to a rotation range θ of about 180 ° is shown. The fixed portion 16 and the rotating shaft 10h are fitted to each other without play in a semicircular notch 45, and are rotatable in synchronization.

A flange 12 is provided between the tip of the rotary shaft 10 and the first bearing 14 so as to be able to contact a step 11 provided at the outer end of the center hole of the housing 2. When an external force in the pushing direction is applied, the contact portion receives the external force. In addition, a seal member 13 such as an O-ring that can slide on the inner surface 2c of the center hole of the housing is provided to prevent dust and water from entering. In FIG. 2, the seal member 13 of the rotating shaft 10 is brought closer to the outside of the housing 2. By shortening the distance m from the seal member 13 to the outside of the angle potentiometer 1, the portion exposed to water or gas is reduced as much as possible.

FIG. 4 shows an example of electric wiring when the angle is detected by the angle potentiometer 1.
A constant voltage is applied to the resistor 23 between the terminals 50 a and 50 c at both ends by the DC power supply 40, and a voltmeter 41 is connected between one terminal 50 b and the terminal 50 c of the electrode section 24. By performing such wiring, both ends 50 of the resistor 23 are formed.
The voltage divided by the brush 26 with respect to the applied voltage between a and 50c is detected by the voltmeter 41. Accordingly, the rotational position of the brush 26, that is, the rotational angle θ of the rotary shaft 10 from the reference point O is detected from this voltage value. As shown in FIG. 5, the relationship between the rotation angle and the output voltage is almost linearly proportional within the rotation angle range. The angle θ of the resistor 23
If the angle of the mechanical stopper is changed, it becomes possible to change the angle to other than 180 degrees. In addition, since the mounting portion to the base-side mounting portion 5 is a joint surface between the rear cover 3 and the housing 2, the rear cover is buried in the mounting hole provided in the base-side mounting portion, so that the protrusion is small. Thus, the entire device can be downsized.

Next, the operation of the embodiment will be described. In FIG. 1, when the rotating shaft 10 is rotated, the fixed portion 16 and the brush 26 rotate together, and a voltage corresponding to the rotation angle of the rotating shaft is generated. The signal is output from the lead wire via the resistor 23 and the electrode unit 24. Since a stopper member 17 is provided on the fixing portion, when the rotation reaches a predetermined rotation angle, the rotation is prevented by the overhanging portion 18 of the rear cover 3, and the brush exceeds the predetermined rotation angle and the brush is moved to the resistor 23 and the electrode portion. 24 does not slide.
Accordingly, the terminal portions 50a, 50b, and the brush 26 are raised by the solder or the conductive adhesive of the resistor 23 and the electrode portion 24.
The 50c riding brush is not damaged. Therefore,
Since the diameter of the resistor 23 can be increased, the linearity can be significantly improved (for example, ± 1% or less).

Although the external force in the pulling direction of the rotating shaft 10 is received by the stopper 15, the pulling force is applied only at the time of assembling or the like and its value is small, so that it can be supported by a small bearing. On the other hand, a relatively large external force in the pushing direction is received in a sliding bearing state by bringing the flange 12 of the rotating shaft 10 into contact with the step portion 11 of the housing 2, so that a large load is withstood. No thrust load is applied to the bearing.

A seal member 13 is provided between the rotary shaft 10 and the center hole 2c of the housing 2, and a hole 32 in the housing is provided.
Urethane resin 54 or the like is applied to the solder portion 29, the lead wire 30, and the substrate portion 33 in the inside, and O
Since the ring 52 is mounted, water does not enter the resistor 23 or the electrode 24.

[0023]

According to the present invention, the resistor and the electrode are disposed on the tip end of the rotating shaft, the brush surface of the brush holder is directed toward the resistor and the electrode, and the brush holder fixing portion is disposed on the opposite side of the resistor. A stopper is provided, the lead wire is taken out from the housing side, and a resistor with a larger outer diameter can be arranged.This improves linearity and enables accurate detection of the rotation angle. However, it has become possible to provide a small angle potentiometer. In addition, since the wiring is provided on the tip side of the rotating shaft, a portion that interferes with the base-side mounting member is reduced, and mounting is simple, reliable, and highly flexible.

Further, since a flange is provided between the tip of the rotary shaft and the first bearing so that the opposite end can contact the step of the housing, even if a large load is applied to the rotary shaft. Since no thrust load is applied to the bearing at the same time as there is no problem of damage, the bearing can be downsized, the space occupied by the stopper can be easily secured, and the angle potentiometer can be downsized.

Further, a seal member is provided between the end of the rotating shaft and the first bearing so as to be able to slide on the inner surface of the center hole of the housing, so that the wiring of the resistor and the electrode section can be waterproofed from the lateral side of the housing to the outside. By extending the cable, the degree of freedom of wiring to the outside was increased and the waterproof performance was enhanced, so that it became easy to prevent dust and water from entering from the outside.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an angle potentiometer according to an embodiment of the present invention.

FIG. 2 is a partially enlarged view showing another embodiment in the vicinity of a flange of a rotary shaft shown in FIG.

FIG. 3 is an explanatory diagram of a resistor and an electrode section of the present invention.

FIG. 4 is a circuit diagram of detecting a resistor.

FIG. 5 is an output diagram of a resistor.

FIG. 6A shows one embodiment of the stopper of the present invention.
It is -A sectional drawing.

FIG. 7 is a sectional view taken along the line AA of FIG. 1 showing another embodiment of the stopper of the present invention.

FIG. 8 is an explanatory view of a conventional resistor and electrode section.

FIG. 9 is a sectional view of a conventional angle potentiometer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Angle potentiometer 2 Housing 2a Center hole 2c Inner surface of center hole of housing 3 Rear lid 10 Rotary shaft 10a Tip of rotary shaft 10j Other end of rotary shaft 11 Step 12 Flange 13 Seal member 14 First bearing 16 Fixed portion 16a Brush holder DESCRIPTION OF SYMBOLS 17 Stopper 18 Stopper (projection part) 19 Second bearing 23 Resistor 24 Electrode part 26 Brush 30 Wiring 32 Housing side side surface

Claims (3)

[Claims] 1. A rotary shaft, a first bearing rotatably supporting the rotary shaft, and a center hole into which the first bearing is inserted so that a tip of the rotary shaft projects outward. A housing in which a resistor and an electrode portion are disposed concentrically with the center hole on the inner surface, a second bearing rotatably supporting the other end of the rotating shaft, and the second bearing is inserted. A rear lid for sealing the housing, wherein the rotating shaft has a first bearing, a brush holder having a brush that slides on the resistor and the electrode portion to change a resistance value, and rotates the brush holder. A fixed portion fixed to a shaft, a stopper which is provided separately or integrally with the fixed portion and limits a rotation range of the rotating shaft, and the second bearing are sequentially provided. Angle potentiometer. 2. A flange portion between the tip of the rotary shaft and the first bearing, the flange having an opposite tip end abuttable on a step of the housing. Angle potentiometer. 3. A seal member is provided between the tip of the rotating shaft and the first bearing, the seal member being slidable on the inner surface of the housing center hole, and the wiring between the resistor and the electrode portion is disposed from the side surface on the housing side. 3. The angle potentiometer according to claim 1, wherein the angle potentiometer is extended to the outside so as to be waterproof.