JP5264835B2 - Optical contactless potentiometer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problems that, in a conventional optical contactless potentiometer, it is difficult to achieve a stable detection accuracy since the detection accuracy of the sensor itself is significantly influenced by shapes of slits and dimensional accuracy of the slits, and assemblability and productivity are poor due to time-consuming assembly work since a light projector is required to be arranged in a narrow space inside a rib of a light shielding plate. <P>SOLUTION: An optical contactless potentiometer includes a rotation shaft 3 rotatably supported by a support member, a light shielding member 4 arranged to face the rotational shaft, a light emitting diode 6 arranged at one side in a direction crossing the direction where the rotation shaft and the light shielding member face each other, and a photo IC 8 arranged on the other side of the direction crossing the direction where the rotation shaft and the light shielding member face each other, to face the light emitting diode. An eccentric rotor 5 for changing a gap between the light shielding member 4 and itself according to the rotational position of the rotation shaft is arranged on the rotation shaft 3. <P>COPYRIGHT: (C)2012,JPO&amp;INPIT

Description

  The present invention relates to a potentiometer that outputs an electrical signal corresponding to a rotation angle. In particular, light is used as a detection medium for the rotation angle, and the optical path is rotated according to the amount of light passing through the optical path by changing the optical path according to the rotation angle. The present invention relates to an optical non-contact potentiometer that detects a rotation angle and a rotation position of a part.

  In general, for example, a potentiometer is widely used as a means for detecting the amount of displacement of an object. Potentiometers can be classified by various classification methods, but can be classified into a contact type and a non-contact type depending on whether or not the detection unit is in contact with the rotating unit. In the present invention, a light amount adjusting unit for changing the optical path is provided between a light emitting unit such as a light emitting diode (LED) and a light receiving unit such as a photo IC, and the amount of light received by the light receiving unit according to the rotation of the light amount adjusting unit. This is an optical non-contact potentiometer that detects the rotation angle and rotation position of the rotary shaft without contact.

JP 7-318370 A

  As a conventional optical contactless potentiometer, for example, there is one described in Patent Document 1. Patent Document 1 describes a rotation angle sensor that can detect a rotation angle in a non-contact manner using light. In the rotation angle sensor described in Patent Document 1, a disk-shaped light shielding plate having a slit is fixed to a rotating shaft, and a projector and a light receiver are arranged on the front and back sides of the light shielding plate. It is characterized by that.

  According to the rotation angle sensor having such a configuration, ribs are provided on the outer peripheral edge of the light shielding plate over the entire circumference, and the ribs reinforce the entire outer peripheral side of the light shielding plate. It is possible to prevent partial twisting on the outer peripheral side of the formation site, suppress cracking of the slit end and deviation of the light incident position of the light receiver, and prevent deterioration of sensor durability and output accuracy. Expected to be effective.

  However, in the optical contactless potentiometer (rotation angle sensor) described in Patent Document 1, a slit is provided in a light shielding plate, and a projector and a light receiver are opposed to each other on both sides of the slit with the light shielding plate interposed therebetween, and pass through the slit. The rotation angle of the light shielding plate is detected by measuring the amount of light to be transmitted. Therefore, since the detection accuracy of the sensor itself is greatly influenced by the shape of the slit and the dimensional accuracy of the slit, there is a problem that it is difficult to obtain stable detection accuracy and productivity is poor. Furthermore, since the projector is arranged inside the rib of the light shielding plate, the projector has to be installed in a narrow space, and the assembly work for the installation takes time and the assemblability is poor. there were.

  The problem to be solved is that in the conventional optical non-contact potentiometer, the detection accuracy of the sensor itself is greatly influenced by the slit shape and the dimensional accuracy of the slit, so it is difficult not only to provide stable detection accuracy. Since the light projector must be arranged in a narrow space inside the ribs of the light shielding plate, it takes time to assemble and poor assembly and productivity.

The optical contactless potentiometer of the present application includes a rotation shaft rotatably supported by a support member, a light shielding member that is installed to face the rotation shaft, and a direction that intersects the direction in which the rotation shaft and the light shielding member face each other. A light emitting unit disposed on one side, and a plurality of light receiving units disposed on the other side in a direction intersecting with the direction in which the rotation shaft and the light shielding member face each other and disposed opposite to the light emitting unit. And the light amount adjustment part which changes the clearance gap between light-shielding members according to the rotation position of the rotation axis is provided in the rotating shaft, and at least one light receiving means among the plurality of light receiving means is a gap formed by the light amount adjusting part. The other light receiving means among the plurality of light receiving means are positions where the amount of received light changes according to the change in the gap by the light quantity adjusting unit. It is characterized by being arranged in .

  According to the optical contactless potentiometer of the present application, the rotational angle and rotational position of the rotary shaft can be accurately detected, the structure is simple, the assembling work is easy, the productivity is excellent, and the size and weight are reduced. An optical non-contact potentiometer that can be realized can be provided.

It is an external appearance perspective view which shows the 1st Example of the optical non-contact potentiometer of this invention. It is a disassembled perspective view which shows the 1st Example of the optical non-contact potentiometer of this invention. It is a top view which shows the 1st Example of the optical non-contact potentiometer of this invention. It is a front view which shows the 1st Example of the optical non-contact potentiometer of this invention. FIGS. 5A and 5B illustrate the operation of the optical contactless potentiometer of the present invention, FIG. 5A shows a state in which the rotation axis is at the initial position, FIG. 5B shows a state in which the rotation axis is displaced by 90 °, and FIG. It is explanatory drawing of each displaced state. It is a graph which shows an example of implementation of the light reception characteristic (relationship between a rotation angle and a light reception area) of photo IC concerning an optical non-contact potentiometer of the present invention. It is a graph which shows the 1st example of implementation of the output characteristic (relationship between a rotation angle and an output voltage) of the light emitting diode which concerns on the optical non-contact potentiometer of this invention. It is a graph which expands and shows the principal part of the output characteristic (relationship between a rotation angle and a deviation) of the light emitting diode shown in FIG. It is a graph which shows the 2nd example of implementation of the output characteristic (relationship between a rotation angle and output voltage) of the light emitting diode which concerns on the optical contactless potentiometer of this invention. 10 is an enlarged graph showing a main part of output characteristics (relationship between rotation angle and deviation) of the light emitting diode shown in FIG. 9. FIG. 11A is a perspective view of an optical contactless potentiometer provided with two light receiving means, and FIG. 11B is a front view of the same. It is block explanatory drawing which shows the 2nd Example of the optical non-contact potentiometer of this invention. FIG. 13A shows a third example of the optical contactless potentiometer according to the present invention. FIG. 13A is a perspective view of an optical contactless potentiometer provided with three light receiving means and two light quantity adjusting units. Is a front view of the same. FIG. 14A shows an optical contactless potentiometer according to a fourth embodiment of the present invention. FIG. 14A is an optical contactless potentiometer provided with two light receiving means and two light receiving means provided by rotating the light amount adjusting portion by 90 °. FIG. 14B is a front view of the same.

  The light-shielding member is placed opposite to the rotating shaft having the light amount adjusting unit, the light-emitting means is arranged on one side of the direction intersecting the direction connecting the rotating shaft and the light-shielding member, and the light-receiving means is arranged on the other side. . As a result, the optical path can be opened and closed by the rotational displacement of the light amount adjusting unit provided on the rotating shaft, and the amount of light passing through the optical path is detected by opening and closing the optical path, and the rotational angle and rotational position accuracy of the rotating shaft are detected. Good detection can be performed with a simple configuration.

  1 to 4 show an example of the first embodiment of the optical contactless potentiometer of the present invention. The optical contactless potentiometer 1 includes a base member 2, a rotating shaft 3, a light shielding member 4, an eccentric rotor 5, a light emitting diode 6 showing a specific example of a light emitting means, a light source holder 7, and a light receiving means. A photo IC 8 showing a specific example, a circuit board 9, and a substrate holder 10 are included.

  As shown in FIGS. 1-4, the base member 2 consists of a disk-shaped member which provided the center hole 12 penetrated to an axial direction in a center part, and the annular groove 13 continuous in the circumferential direction is formed in the outer peripheral surface. And the end surface groove | channel 14 which continues in the circumferential direction is provided. The annular groove 13 is provided at an intermediate portion in the width direction of the outer peripheral surface, and is provided to be supported by a mounting claw not shown. The end surface groove 14 is provided on one side in the width direction of the outer peripheral surface, and an end portion on the open side of a cylindrical cap (not shown) is fitted. Further, the end face of the base member 2 on the end face groove 14 side has a first guide groove 15 extending in a diametrical direction through a position slightly offset from the center portion, and one side of the first guide groove 15. And a second guide groove 16 extending in the radial direction so as to be orthogonal to the first guide groove 15.

  Bearing members 17 such as ball bearings are fitted into both side openings of the central hole 12 of the base member 2. The rotary shaft 3 is a cylindrical shaft having a small cross-sectional shape with a small diameter portion 3a having a small diameter on one side in the axial direction, and two bearing members 17 are provided in a substantially central portion in the axial direction. Are fitted with an interval of. The two bearing members 17 fitted to the rotating shaft 3 are prevented from coming off by two retaining rings 18 and 18 which are arranged on both sides of the rotating shaft 3 and engaged with annular grooves provided in the large diameter portion. Thereby, the rotating shaft 3 is supported with respect to the base member 2 so as to be rotatable only in the rotating direction while being prevented from moving in the axial direction.

  At this time, the rotating shaft 3 has a small-diameter portion 3a that protrudes to the end surface side where the first and second guide grooves 15 and 16 of the base member 2 are located, and a large-diameter portion of the rotating shaft 3 protrudes to the opposite end surface side. Has been. An eccentric rotor 5 is fitted to the small diameter portion 3 a of the rotating shaft 3, and the eccentric rotor 5 is rotated integrally with the rotating shaft 3. The axial hole 21 of the eccentric rotor 5 is provided eccentrically by a distance E with respect to the center line O2 of the cylindrical axis. That is, the eccentric rotor 5 is composed of a pipe-shaped eccentric cylindrical shaft in which an axial hole 21 penetrating in the axial direction is eccentric by a predetermined distance E from the center line O2 to one side. The diameter of the axial hole 21 of the eccentric rotor 5 is set to a size commensurate with the outer diameter of the small-diameter portion 3a, and is formed to have a size that can be fitted into the small-diameter portion 3a without generating a substantial gap.

  The eccentric rotor 5 is screwed to the small diameter portion 3 a by a fixing screw 22. Therefore, the small-diameter portion 3a is provided with a screw hole 23 that is opened at the end face and extends in the axial direction. The eccentric rotor 5 is fixed to the rotary shaft 3 by pressing one end of the eccentric rotor 5 toward the large diameter portion with the head of the fixing screw 22 screwed into the screw hole 23. A light amount adjustment that adjusts the amount of light irradiated to the light receiving means by changing the amount of light radiated from the light emitting means according to the rotation angle of the rotating shaft 3 by the small diameter portion 3a of the rotating shaft 3 and the eccentric rotor 5. The part is composed. In this embodiment, the light quantity adjustment unit is configured by two members, that is, the rotating shaft 3 having the small diameter portion 3a and the eccentric rotor 5, but the eccentric portion is integrally provided on the rotating shaft 3 with one member. A light amount adjustment unit can also be configured.

  As shown in FIG. 3 and the like, the light shielding member 4 is disposed in the second guide groove 16 extending in the radial direction so as to face the eccentric rotor 5 fixed to the rotating shaft 3. The light source holder 7 is disposed on one side of the first guide groove 15 extending in a direction orthogonal to the second guide groove 16, and on the other side of the first guide groove 15 with the rotation shaft 3 interposed therebetween. A substrate holder 9 is arranged. In FIG. 3, the symbol X indicates the first direction, and the symbol Y indicates the second direction orthogonal to the first direction X. Reference numeral X1 denotes a first reference line that passes through the center point O1 of the base member 2 and the rotation shaft 3 and extends in the first direction X, and reference numeral Y1 passes through the center point O1 and passes through the first point X1. The 2nd reference line extended in the 2nd direction Y orthogonal to this reference line X1 is shown. Reference numeral X <b> 2 indicates a guide center line of the first guide groove 15. The guide center line X2 is provided parallel to the first reference line X1 by being decentered by a distance H.

  The light shielding member 4 sets the width of the optical path between the eccentric rotor 5 and is fixed to the base member 2 by a fixing screw 24. The light shielding member 4 includes a fixing portion 4a that is positioned at a predetermined position of the base member 2 by engaging with the second guide groove 16, and a light shielding portion that is provided integrally with the fixing portion 4a and partitions one side of the optical path. 4b. An insertion hole 32 is provided in the fixed portion 4 a, and a screw hole 33 is provided in the second guide groove 16 of the base member 2 corresponding to the insertion hole 32. The light shielding member 4 is fixed to the base member 2 by a fixing screw 34 that passes through the insertion hole 32 and is screwed into the screw hole 33. An opposing surface 4 c of the light shielding member 4 b facing the eccentric rotor 5 of the light shielding member 4 is a vertical surface parallel to the outer peripheral surface of the eccentric rotor 5. And the clearance gap between the opposing surface 4c and the outer peripheral surface of the small diameter part 3a is formed uniformly over the full length from the one end of the small diameter part 3a to the other end.

  The light source holder 7 is engaged with the first guide groove 15 and is fixed to the fixed position 7a for positioning the light source holder 7 at a predetermined position of the base member 2, and is provided integrally with the fixed portion 7a and serves as a light source. It comprises a holding portion 7b for holding a light emitting diode 6 as a light emitting means. The fixing portion 7a of the light source holder 7 is formed wider than the width of the first guide groove 15, and an engaging portion 7c that is engaged with the first guide groove 15 is provided at the center of the lower surface thereof. ing. Insertion holes 25 are provided on both sides of the fixed portion 7a, and a pair of screw holes 35, 35 are provided in the base member 2 corresponding to the respective insertion holes 25. The light source holder 7 is screwed and fixed to the base member 2 by two fixing screws 26 that pass through the insertion holes 25 and are screwed into the screw holes 35.

  The holding part 7b of the light source holder 7 is formed so as to protrude upward from the center of the upper surface of the fixing part 7a. A through hole 27 penetrating in the horizontal direction is provided in an intermediate portion in the height direction of the holding portion 7b. The light emitting diode 6 is fitted and attached to the through hole 27. The light-emitting diode 6 includes a light-emitting diode chip that emits light, a casing 6a that houses the light-emitting diode chip, and a pair of terminal pins that seal the opening on the back side of the casing 6a and are connected to the light-emitting diode chip. Terminal board 6b from which 28 and 28 protrude. In addition, the holding portion 7 b is provided with a screw hole 29 having one end opened on the upper surface and the other end communicated with the through hole 27. The light emitting diode 6 is screwed to the holding portion 7b of the light source holder 7 by the set screw 31 screwed into the screw hole 29, and is integrally fixed.

  The substrate holder 10 is fixed to a fixing portion 10a for positioning and fixing at a predetermined position of the base member 2, and a circuit board 9 provided integrally with the fixing portion 10a and holding a photo IC 8 as a light receiving means. It consists of a holding part 10b. The fixed portion 10a of the substrate holder 10 is formed wider than the width of the first guide groove 15, and an engaging portion 10c that is engaged with the first guide groove 15 is provided at the center of the lower surface thereof. ing. An insertion hole 36 is provided at the center of the fixed portion 10 a, and a screw hole 37 is provided in the first guide groove 15 of the base member 2 corresponding to the insertion hole 36. The substrate holder 10 is screwed and fixed to the base member 2 by a fixing screw 38 that passes through the insertion hole 36 and is screwed into the screw hole 37.

  The circuit board 9 is fixed to the inner surface of the holding part 10b of the substrate holder 10 by screwing. The circuit board 9 is provided with a circuit pattern having a predetermined shape (not shown), and a photo IC 8 is disposed at a substantially central portion of the circuit pattern and is electrically connected to the circuit pattern. As shown in FIGS. 3 and 4, the photo IC 8 mounted on the circuit board 9 is set at the same height as the light emitting diode 6, and the central portion of the light receiving portion 41 of the photo IC 8 and the radiating portion of the light emitting diode 6. Are opposed to each other on the same horizontal line.

  The positional relationship among the rotating shaft 3, the light shielding member 4, the eccentric rotor 5, the light emitting diode 6, and the photo IC 8 will be described in detail with reference to FIGS. 5A to 5C are explanatory views of the positional relationship between the rotary shaft 3 and the eccentric rotor 5 and the like viewed in a plane. An axis O1 which is the rotation center of the rotary shaft 3 and the small diameter portion 3a is set on the first reference line X1 extending in the first direction X. A guide center line X2 that forms the center line of the first guide groove 15 is set at a position separated from the first reference line X1 by a distance H. On the guide center line X2, the light emitting diode 6 The center of the radiation part and the center of the light receiving part 41 of the photo IC 8 are configured to overlap each other. The photo IC 8 is obtained by integrating a light receiving element and a signal processing circuit, and the horizontal length of the light receiving element (light receiving portion) is G.

  In addition, a second reference line Y1 passing through the axial center line O1 and extending in the second direction Y is set at a substantially intermediate portion between the radiation portion of the light emitting diode 6 and the light receiving portion 41 of the photo IC 8. . The rotating shaft 3, the eccentric cam 5, and the shielding member 4 are arranged so as to face each other in the direction in which the second reference line Y1 extends. FIG. 5A shows a state in which the center line O2 of the eccentric rotor 5 is rotated to a position farthest from the light shielding member 4, and this state is referred to as “rotation shaft 180 ° position” in the present embodiment. . At this time, the gap F1 between the eccentric rotor 5 and the light shielding member 4 is twice the eccentric amount E of the eccentric rotor 5 (F1 = 2E). The gap F1 is set to a size equal to the length G of the light receiving portion 41 of the photo IC 8 (F1 = G = 2E).

  FIG. 5B shows a state in which the eccentric rotor 5 is rotated 90 degrees clockwise from the state of FIG. 5A and the center line O2 of the eccentric rotor 5 is rotated on the first reference line X1. In the embodiment, it is referred to as “rotation axis 90 ° position”. At this time, the gap F2 between the eccentric rotor 5 and the light shielding member 4 is equal to 1/2 of the length G of the light receiving portion 41, that is, the eccentric amount E of the eccentric rotor 5 (F2 = G / 2). = E).

  FIG. 5C shows a state in which the eccentric rotor 5 is further rotated 90 degrees clockwise from the state of FIG. 5B and the center line O2 of the eccentric rotor 5 is rotated to a position closest to the light shielding member 4. In this embodiment, these are referred to as “rotation axis 0 ° position”. At this time, the eccentric rotor 5 is in contact with the light shielding member 4, and the gap F0 between the eccentric rotor 5 and the light shielding member 4 is 0 (F0 = 0 <G).

  In the present embodiment, the example in which the eccentric amount E of the eccentric rotor 5 is set to the same length as the length of one side of the light receiving portion 41 of the photo IC 8 (the length in the horizontal direction) has been described. With this configuration, the change in the gap F between the eccentric rotor 5 and the light shielding member 4 is reflected in the change in the sine curve of the light shielding amount due to the eccentric amount E of the eccentric rotor 5. It can be measured as a change in the light shielding amount in the light receiving unit 41. Therefore, the rotation angle of the rotating shaft 3 can be detected as a change in the amount of light received by the photo IC 8 and output as a voltage proportional to the amount of light received. As a result, the output of the photo IC 8 can be taken out as a linear analog voltage output corresponding to the rotation angle of the rotary shaft 3.

  In the present embodiment, a portion from 90 ° to ± 45 ° that becomes a pseudo linear change on the sin curve is used. As a result, an approximately linearly changing analog voltage output can be obtained by utilizing a substantially linearly changing portion obtained based on the rotation of the rotating shaft 3. In the present embodiment, the case where “the eccentric amount E of the eccentric rotor 5 is made equal to the length of one side of the light receiving portion 41 of the photo IC 8” has been described, but the present invention is not limited to this. Alternatively, the configuration may be such that “the eccentric amount E of the eccentric rotor 5 is longer than the length of one side of the light receiving portion 41 of the photo IC 8”. In this case, the sin curve change can be sharpened, and a large analog voltage output can be obtained based on a small rotation angle.

  Examples of the material of the base member 2, the rotating shaft 3, the light shielding member 4, the eccentric rotor 5, the light source holder 7 and the substrate holder 10 include, for example, aluminum alloy, copper alloy, steel steel, stainless steel and other metals, ABS, (Acrylonitrile butadiene styrene resin), POM (polyacetal) and other engineering plastics can be used.

  The optical contactless potentiometer 1 having the above-described configuration can be assembled, for example, as follows. First, the two bearing members 17 and 17 are fitted into the central hole 12 of the base member 2, and the two bearing members 17 and 17 are attached to the base member 2. Next, the rotating shaft 3 is inserted into the holes of the two bearing members 17 and 17 attached to the base member 2. Then, retaining rings 18 are respectively fitted in two annular grooves provided in the large-diameter portion of the rotating shaft 3, and the two bearing members 17, 17 are sandwiched from both sides by the two retaining rings 18, 18. To prevent it from falling out. Next, the small diameter portion 3 a of the rotating shaft 3 is fitted into the axial hole 21 of the eccentric rotor 5. Then, the fixing screw 22 is screwed onto the tip of the small diameter portion 3a, and the fixing screw 22 is tightened to fix the eccentric rotor 5 to the small diameter portion 3a.

  Next, the fixing portion 4 a of the light shielding member 4 is fitted into the second guide groove 16 of the base member 2, and the light shielding member 4 is fixed to the base member 2 by the fixing screw 34. Next, the light emitting diode 6 is fitted into the through hole 27 provided in the holding portion 7 b of the light source holder 7, and the set screw 31 is screwed into the screw hole 29 to fix the light emitting diode 6. Next, the engaging portion 7 c provided on the fixing portion 7 a of the light source holder 7 is fitted into one side of the first guide groove 15 of the base member 2, and the fixing portion 7 a is fixed to the base member 2 by the fixing screw 26.

  Next, the circuit board 9 on which the photo IC 8 is mounted is fixed to the one surface of the holding portion 10a of the board holder 10 by screwing. Then, the engaging portion 10 c provided on the fixing portion 10 a of the substrate holder 10 is fitted into the other side of the first guide groove 15 of the base member 2, and the light source holder 7 is fixed to the base member 2 with the fixing screw 26. As a result, the light emitting diode 6 and the photo IC 8 are opposed to each other with the light shielding member 4 and the eccentric rotor 5 interposed therebetween. Then, the assembly work of the optical contactless potentiometer 1 is completed.

  According to the optical non-contact potentiometer 1, the eccentric rotor 5 is attached to the rotary shaft 3 supported by the base member 2, and the light shielding member 4 and the light source holder 7 are provided on one surface of the base member 2 so as to surround the eccentric rotor 5. The assembly process can be completed simply by assembling the substrate holder 10. Therefore, the assembling work can be performed easily and quickly, and the adjustment work for adjusting the position after the assembling can be performed easily and quickly.

  The optical contactless potentiometer 1 having such a configuration can be used as follows, for example. The optical non-contact potentiometer 1 is intended to detect the rotation angle of the rotary shaft 3 and output a signal corresponding to the detection result. As a result, various devices, devices, systems, and the like can be controlled according to the rotation angle of the rotation shaft 3. In order to achieve this object, in this embodiment, the light-emitting diode 6 as the light-emitting means and the photo IC 8 as the light-receiving means are installed facing each other, and a cylindrical shape having an eccentricity E in the optical path connecting them. The eccentric rotor 5 (light quantity adjustment unit) and the light shielding member 4 are provided.

  Then, the eccentric rotor 5 is rotated by the rotation of the rotating shaft 3 to change the gap between the light shielding member 4 in a wide and narrow manner (sin curve change), and the change in the gap is detected as a change in the amount of light received by the photo IC 8. In particular, the rotation angle of the rotary shaft 3 is utilized by utilizing the range of the rotation axis 0 ° to 90 ° ± 45 ° (45 ° to 135 °) that is a pseudo linear change on the sin curve. An optical non-contact potentiometer 1 that can obtain a linear analog voltage output according to the above is configured. As the range of the sin curve change, a range from 0 ° to 270 ° ± 45 ° (225 ° to 315 °) of the rotation axis that is also a pseudo linear change on the sin curve can be used. Further, the range of the sin curve change is not limited to ± 45 °, but may of course be ± 40 °, ± 35 °, ± 30 °, and the like.

FIG. 6 is a graph in which the relationship between the rotation angle (°) of the rotating shaft 3 and the light receiving area (light receiving amount) in the light receiving part (light receiving element made of a square having a side of 0.6 mm) 41 of the photo IC 8 is calculated. The horizontal axis represents the rotation angle (°) of the rotary shaft 3, and the vertical axis represents the light receiving area (mm ² ). “TLN117 (F): Toshiba infrared LED GaAs infrared light emission” manufactured by Toshiba Corporation was used as the light emitting diode (LED), and “MLX75305” manufactured by Melexis was used as the photo IC8.

The relationship between the rotation angle when the rotating shaft 3 is rotated once and the output voltage (V) output from the photo IC 8 is as shown in FIG. 6, and the change in the calculated value is a sin curve. Yes. When the rotation angle of the rotating shaft 3 is “rotating shaft 0 ° position (state of FIG. 5C)” (= rotating shaft 360 ° position), the light receiving area is 0 (mm ² ). Between the rotation angle 0 ° and the rotation angle 45 °, and between the rotation angle 215 ° and the rotation angle 360 °, the calculated value changes in a curved line.

  On the other hand, when the rotation angle is about 45 ° to about 135 ° and between about 215 ° to about 315 °, the calculated value changes substantially linearly. Therefore, since the light receiving area and the output voltage are considered to be in a substantially proportional relationship, the rotation angle is about 45 ° to about 135 ° (± 45 ° centering on the rotation shaft 90 ° position) M1, or A linear output voltage corresponding to the rotation angle is obtained by using a pseudo linear change in M2 when the rotation angle is about 215 ° to about 315 ° (± 45 ° centered on the rotation shaft 270 ° position). Like that. In FIG. 6, a sin curve indicated by a broken line indicates a state in which a 90 ° phase is advanced from the sin curve indicated by a solid line.

  FIG. 7 shows the results of experiments using “TLN108 (F)” for the LED 6 and “MLX75305” for the photo IC 8. In the graph shown in FIG. 7, the horizontal axis represents the rotation angle (°) of the rotary shaft 3 and the vertical axis represents the output voltage (V) of the photo IC 8. At a rotation angle of 0 °, the output voltage 0 (V) gradually increases in a curve as the rotation angle increases, and at a rotation angle of 45 °, the output voltage increases to about 0.9 (V). . The output voltage increases linearly from the rotation angle 45 ° to the rotation angle 135 ° so as to be proportional to the increase in the rotation angle. At the rotation angle 135 °, the output voltage is about 4.7 (V).

  Thereafter, the output voltage changes so as to draw a gentle curve, and the output voltage reaches a maximum value of about 5.3 (V) at a rotation angle of 180 °. When the rotation angle of the rotary shaft 3 exceeds 180 °, the output voltage characteristics are opposite to the previous characteristics, and the output voltage gradually decreases to draw a curve up to the rotation angle of about 225 °. The output voltage decreases linearly from the rotation angle 225 ° to the rotation angle 315 ° so as to be inversely proportional to the increase in the rotation angle, and the output voltage is about 0.9 (V) at the rotation angle 315 °. . Therefore, either the rotation angle between 45 ° and 135 °, or the rotation angle between 225 ° and 315 °, in which the output voltage is substantially linear (in this embodiment, the rotation in the first rotation period). The angle between 45 ° and 135 ° is used.

  FIG. 8 is a graph showing a deviation (% FS) between a rotation angle of 45 ° and 135 °, which is a pseudo linear change, in the experimental result shown in FIG. This deviation is made by connecting the two points with straight lines with the deviations of the two rotation angles of 45 ° and 135 ° being set to 0, and how much deviation (% FS) occurs at each rotation angle with respect to this straight line. Represents. As a result, the deviation (% FS) appeared on the minus side in the front portion (45 ° to 90 °) of the rotation angle, and the maximum value was about −2.1 (% FS). In addition, the rear portion (90 ° to 135 °) of the rotation angle appears on the plus side, the maximum value is about +3.3 (% FS), and the average value of deviation is ± 2.8 (% FS). Met.

  FIG. 9 shows an experiment using “MLX75305” for the photo IC 8 and using “TLN117 (F): manufactured by Toshiba Corporation” which is a small and low cost instead of “TLN108 (F)” for the LED 6. Results are shown. In the graph shown in FIG. 9, the horizontal axis represents the rotation angle (°) of the rotary shaft 3, and the vertical axis represents the output voltage (V) of the photo IC 8. The output voltage (V) is about 0 (V) to 0.4 (V) between the rotation angles of 0 ° and 45 °. On the other hand, when the rotation angle exceeds 45 °, the output voltage (V) increases linearly in proportion to the increase of the rotation angle until the rotation angle is about 140 °. Of about 5.5 (V).

  Between the rotation angle of about 140 ° and the rotation angle of about 255 °, the output voltage does not change and the output voltage of about 5.5 (V) is maintained. When the rotation angle exceeds 255 °, the output voltage decreases linearly so as to be inversely proportional to the increase in the rotation angle, and the output voltage becomes about 0.4 (V) at the rotation angle of 350 °. Yes. Therefore, either the output voltage exhibits substantially linearity, between the rotation angle of 45 ° and about 135 °, or between the rotation angle of about 255 ° and 345 ° (in this embodiment, the rotation in the first rotation period). The angle between 45 ° and 135 ° is used.

  FIG. 10 is a graph showing the deviation (% FS) between the rotation angle 45 ° and 135 °, which is a pseudo linear change, in the experimental result shown in FIG. This deviation is made by connecting the two points with straight lines with the deviations of the two rotation angles of 45 ° and 135 ° being set to 0, and how much deviation (% FS) occurs at each rotation angle with respect to this straight line. Represents. As a result, the deviation (% FS) appeared on the minus side in the initial part (45 ° to 58 °) of the rotation angle, and the maximum value was about −0.7 (% FS). The remaining part of the rotation angle (the part excluding the initial part) (58 ° to 135 °) appears on the plus side, the maximum value is about +2.5 (% FS), and the average deviation is ± 1.5 (% FS). The average value ± 1.5 (% FS) of the deviation is a value that can sufficiently be used as a deviation representing linearity in the detection unit of the angle sensor.

  The optical contactless potentiometer 1 having such a configuration can be used as follows, for example. This optical contactless potentiometer 1 is an angle detection sensor that detects the rotation angle of a rotating shaft that rotates within an angle range of a rotation range of ± 45 ° (total 90 °). First, the large-diameter side of the rotating shaft 3 of the optical contactless potentiometer 1 assembled as described above is connected to a rotating shaft for detecting a rotation angle via a connecting component such as a joint or a connecting device such as a clutch. Link. Then, light is emitted from the light emitting diode 6 held by the light source holder 7 toward the photo IC 8, and the light is received by the photo IC 8 mounted on the circuit board 9 held by the substrate holder 10.

  At this time, the eccentric rotor 5 disposed on the optical path of the light emitted from the light emitting diode 6 is rotated integrally with the rotating shaft 3, and the light quantity received by the light receiving portion (light receiving element) 41 of the photo IC 8 before and after the rotation. The rotation angle of the rotary shaft 3 can be detected by the change of

  As shown in FIG. 5A, in the state where the clearance F1 between the outer peripheral surface of the eccentric rotor 5 and the opposing surface 4c of the light shielding member 4 is at the widest rotation axis position of 180 °, the optical path is blocked by the eccentric rotor 5. In other words, the gap F1 is equal to the horizontal length G of the light receiving portion (light receiving element) 41 of the photo IC 8 (F1 = G = 2E). Therefore, the light receiving portion (light receiving element) 41 of the photo IC 8 is irradiated with light emitted from the light emitting diode 6 on the entire surface, and the light receiving rate of the light receiving portion 41 is 100%.

  As shown in FIG. 5B, in the state where the rotating shaft 3 is rotated 90 degrees from the state of FIG. 5A and is rotationally displaced to the position of the rotating shaft 90 °, half of the optical path is shielded by the eccentric rotor 5, The gap F2 is ½ of the horizontal length G of the light receiving portion (light receiving element) 41 of the photo IC 8 (F2 = G / 2 = E). Therefore, the light emitted from the light emitting diode 6 is irradiated to the light receiving part (light receiving element) 41 of the photo IC 8 in a half area, and the light receiving rate of the light receiving part 41 becomes 50%.

  Further, as shown in FIG. 5C, in the state where the rotating shaft 3 is further rotated 90 degrees from the state of FIG. 5B and is rotationally displaced to the position of the rotating shaft 0 °, the optical path is completely blocked by the eccentric rotor 5, and the gap F0 is 0 (F0 = 0 <G). Therefore, the light receiving part (light receiving element) 41 of the photo IC 8 is not irradiated with light emitted from the light emitting diode 6 on the area, and the light receiving rate of the light receiving part 41 becomes 0%.

  11A and 11B show an optical contactless potentiometer 50 showing a second embodiment of the present invention. The optical contactless potentiometer 50 shown as the second embodiment is provided with two photo ICs 51 and 52 as light receiving means, and the light receiving area changes according to the rotation angle by using the first photo IC 51 as a detection sensor. On the other hand, the second photo IC 52 is used as a reference sensor so that light is always applied to the entire area of the light receiving unit. Then, the light emitting diode 6 is feedback-controlled by the illuminance sensed by the second photo IC 52 so that the output of the first photo IC 51 is stabilized.

  The optical contactless potentiometer 50 is different from the optical contactless potentiometer 1 according to the first embodiment described above in that two photo ICs 51 and 52 are provided as light receiving means. It is the same as the embodiment. Therefore, here, the difference between the optical contactless potentiometer 50 and the optical contactless potentiometer 1 will be described, and the same portions will be denoted by the same reference numerals, and redundant description will be omitted. The first photo IC 51 and the second photo IC 52 are the same. Further, as the light emitting diode 6, one having a large (wide) directivity angle is used so that the light receiving portions 41, 41 of the two photo ICs 51, 52 installed side by side can be irradiated with light having the same intensity. To do.

  As shown in FIGS. 11A and 11B, the two photo ICs 51 and 52 are mounted on the same surface of the circuit board 9 with a predetermined gap. The circuit board 9 is fixed to the substrate holder 10 with the two photo ICs 51 and 52 arranged in the vertical direction and the light receiving portions 41 facing the light emitting diodes 6. The first photo IC 51 is for output, and a second photo IC 52 for feedback control is disposed above the first photo IC 51. A horizontal center line N1 extending in the horizontal direction from the center of the light emitting diode 6 that emits light is set at an intermediate portion between the first photo IC 51 and the second photo IC 52. Therefore, the distance from the light receiving portion 41 of the first photo IC 51 to the horizontal center line N1 is equal to the distance from the light receiving portion 41 of the second photo IC 52 to the horizontal center line N1.

  Further, the height of the upper end surface of the eccentric rotor 5 fixed to the rotating shaft 3 is configured to coincide with the position of the horizontal center line N in the height direction. As a result, the light receiving unit 41 of the first photo IC 51 receives the amount of light that changes in the sin curve according to the rotation angle of the eccentric rotor 5 and outputs an analog voltage (V) corresponding to the amount of received light. On the other hand, the light receiving unit 41 of the second photo IC 52 is always irradiated with light over the entire area regardless of the rotation angle of the eccentric rotor 5. From the second photo IC 52, the intensity of the light emitted from the light emitting diode 6 can be known.

  In general, light emitted from a light-emitting diode is affected by ambient ambient temperature, heat generation of the light-emitting diode itself, change with time of the light-emitting diode due to long-term use, and the like, and the light intensity changes. For this reason, when one photo IC is used as the light receiving means, the influence of the ambient temperature or the like is added to the detection value of the photo IC, and the one under the influence is acquired as the detection value. Become. Therefore, in this case, the output value of the photo IC lacks stability, and it becomes difficult to obtain a highly accurate detection value. On the other hand, in the optical non-contact potentiometer 50 according to the present embodiment, the second photo IC 52 senses the illuminance affected by the ambient temperature and the heat generation of the LED itself, and the light emitting diode 6 is based on the illuminance. Feedback control. As a result, the output voltage of the first photo IC 51 can be stabilized and the rotation angle can be detected with high accuracy.

  FIG. 12 is a block diagram showing a circuit configuration of the optical contactless potentiometer 50. An LED driving constant current circuit 53 is connected to the light emitting diode 6. The LED driving constant current circuit 53 is a circuit for stabilizing the intensity of light emitted from the light emitting diode 6 and drives the light emitting diode 6 at a constant current to emit stable light. The light emitted from the light emitting diode 6 is simultaneously applied to the first photo IC 51 and the second photo IC 52. At this time, the light receiving unit 41 of the first photo IC 51 is irradiated with light whose optical path is adjusted by the eccentric rotor 5, and the light receiving unit 41 of the second photo IC 52 is always irradiated with light over the entire area.

  The first photo IC 51 outputs a voltage corresponding to the area irradiated with light passing through the optical path adjusted by the rotation of the eccentric rotor 5. An output adjustment amplifier circuit 54 is connected to the first photo IC 51, and the voltage output of the first photo IC 51 is output to the outside through the output adjustment amplifier circuit 54. The second photo IC 52 outputs a voltage when the entire area of the light receiving unit 41 is irradiated with light. A feedback processing circuit 55 is connected to the second photo IC 52, and the feedback processing circuit 55 controls the LED driving constant current circuit 53 based on the voltage when light is applied to the entire area of the light receiving unit 41. To do.

  For example, when the intensity of light emitted from the light emitting diode 6 is increased due to an increase in ambient temperature or a temperature increase due to heat generation of the LED itself, the feedback processing circuit 55 supplies the LED driving constant current circuit 53 to the LED driving constant current circuit 53. Then, a control signal for lowering the value of the constant current output from the LED driving constant current circuit 53 is output. In addition, when the light emitting diode 6 deteriorates due to long-term use and the intensity of emitted light becomes weak, a control signal for increasing the value of the constant current output from the LED driving constant current circuit 53 is: It is output from the feedback processing circuit 55 to the LED driving constant current circuit 53. By performing such feedback control, the output of the light emitting diode 6 is kept constant and the first photo IC 51 even when the ambient temperature rises, the LED itself generates heat, or the light intensity deteriorates due to changes over time. Output can be stabilized and detection accuracy can be improved.

  13A and 13B show an optical non-contact potentiometer 50 showing a third embodiment of the present invention. The optical contactless potentiometer 60 shown as the third embodiment is configured so that two identical outputs can be taken out individually. The optical contactless potentiometer 60 is different from the optical contactless potentiometer 50 according to the second embodiment described above in that three photo ICs 61, 62, 63 are provided as light receiving means, and two eccentric rotors 65 are provided. , 66, and the rest of the configuration is the same as in the previous embodiment. Therefore, here, the difference between the optical non-contact potentiometer 60 and the optical non-contact potentiometer 50 will be described, and the same parts are denoted by the same reference numerals, and redundant description will be omitted.

  The first to third photo ICs 61 to 63 are the same. In addition, as the light emitting diode 6, a light emitting diode having a particularly large (wide) directivity angle is used so that the light receiving portions 41 of the three photo ICs 61 to 63 arranged side by side can be irradiated with light having the same intensity. .

  The optical non-contact potentiometer 60 has three photo ICs 61, 62, and 63 as light receiving means, and the light receiving area is set at a rotation angle by using the first photo IC 61 and the third photo IC 63 as detection sensors. It is configured to change accordingly. The second photo IC 62 is used as a reference sensor so that the entire area of the light receiving unit is always exposed to light. In addition, two eccentric rotors 65 and 66 are provided as a light amount adjusting unit, the first eccentric rotor 65 is disposed to face the first photo IC 61, and the second eccentric rotor 66 is disposed on the third photo IC 63. They are installed facing each other. The light emitting diode 6 is feedback-controlled by the illuminance sensed by the second photo IC 62, and the outputs of the first photo IC 61 and the third photo IC 63 are stabilized.

  As shown in FIGS. 13A and 13B, the three photo ICs 61 to 63 are mounted in a line on the same surface of the circuit board 9 with a predetermined gap. The circuit board 9 is fixed to the substrate holder 10 with the three photo ICs 61, 62, 63 arranged in the vertical direction and the respective light receiving portions 41 facing the light emitting diodes 6. The first photo IC 61 is for the first output, and the third photo IC 63 is for the second output. A second photo IC 62 for feedback control is arranged above the first photo IC 61, and a third photo IC 63 for second output is arranged above the second photo IC 62.

A horizontal center line N2 extending in the horizontal direction from the center of the light emitting diode 6 that emits light is set at the center of the second photo IC 62. Therefore, the distance from the light receiving part 41 of the first photo IC 61 to the horizontal center line N2 is equal to the distance from the light receiving part 41 of the third photo IC 63 to the horizontal center line N2.

  Further, the two eccentric rotors 65 and 66 fixed to the rotating shaft 3 have a height (length in the axial direction) substantially equal to the height (length of one side) of the photo ICs 61 to 63. Is set to In the horizontal direction, the first eccentric rotor 65 is opposed to the first photo IC 61, and the second eccentric rotor 66 is opposed to the third photo IC 63. Further, the small-diameter portion 3a of the rotating shaft 3 is opposed to the second photo IC 62 so that the entire surface of the light receiving portion 41 is irradiated with light regardless of the rotation angle of the rotating shaft 3. In addition, by interposing a cylindrical sleeve between the two eccentric rotors 65 and 66, the interval between the two eccentric rotors 65 and 66 is kept constant, and the rotation shaft 3 is fixed to the rotating shaft 3 by the fixing screw 22. Assembly can be performed.

  That is, the height of the upper end surface of the first eccentric rotor 65 is set at an intermediate portion between the first photo IC 61 and the second photo IC 62, and the height of the lower end surface of the second eccentric rotor 66 is It is set at an intermediate portion between the second photo IC 62 and the third photo IC 63. As a result, the light receiving portion 41 of the first photo IC 61 receives the amount of light that changes in the sin curve according to the rotation angle of the first eccentric rotor 65, and the analog voltage (V) corresponding to the amount of received light is the first. Output from the photo IC 61. The light receiving unit 41 of the third photo IC 63 receives the amount of light that changes in the sin curve according to the rotation angle of the second eccentric rotor 66, and the analog voltage (V) corresponding to the amount of received light is the third voltage. Output from the photo IC 63.

  On the other hand, the light receiving unit 41 of the second photo IC 62 is always irradiated with light over the entire area regardless of the rotation angle of the rotary shaft 3. From the second photo IC 62, the intensity of light emitted from the light emitting diode 6 can be known. Then, by separately outputting voltages based on the two detection values detected by the two photo ICs 61 and 63, it is possible to simultaneously control two external devices using the two output voltages.

  14A and 14B show an optical contactless potentiometer 70 showing a fourth embodiment of the present invention. The optical contactless potentiometer 70 shown as the fourth embodiment is different from the optical contactless potentiometer 60 according to the third embodiment described above in that the second eccentric rotor 67 is different from the first eccentric rotor 65. Is configured to be rotated and displaced by 90 °, and the other configuration is the same as that of the above embodiment. Therefore, here, the difference between the optical non-contact potentiometer 70 and the optical non-contact potentiometer 60 will be described, and the same parts are denoted by the same reference numerals, and redundant description will be omitted.

  The shapes and sizes of the two eccentric rotors 65 and 67 are the same as those of the optical contactless potentiometer 60 according to the third embodiment. Similarly, the means for attaching the two eccentric rotors 65 and 67 to the rotating shaft 3 is the same, and by inserting a cylindrical sleeve between the two eccentric rotors 65 and 67, the two eccentric rotors 65 and 67, It is possible to assemble the rotary shaft 3 while keeping the distance between the 66 constant. The outputs of the two photo ICs in this embodiment can obtain two voltage outputs whose phases are shifted by 90 degrees, for example, based on the change in the light receiving area as shown in FIG.

  The output of the optical contactless potentiometer 70 according to the fourth embodiment can be used as follows, for example. For example, the output of the first photo IC 61 is used as a main output, while the output of the third photo IC 63 is used as a limiter to prevent the rotary shaft 3 from being rotationally displaced beyond an allowable range. Specifically, the detection angle range of the first photo IC 61 is set to 90 ° ± 45 °, and the third photo IC 63 having the same detection angle range is set to advance 90 °. With this configuration, it is possible to know whether the output of the first photo IC 61 for main detection is correct or not by looking at the output of the third photo IC 63 for limiter.

  Assuming that the first photo IC 61 detects the range of the rotation angle 3 of the rotating shaft 3 up to 90 ° ± 45 ° (+ 45 ° to + 135 °), the third photo IC 63 at this time has a rotation angle of 0 °. The detection is within the range of ± 45 ° (−45 ° to + 45 °). Therefore, when the output of the first photo IC 61 is an appropriate detection value obtained within the above range, the output of the third photo IC 63 is an inappropriate detection value outside the range that cannot be obtained within the above range. Become. In other words, when the output of the third photo IC 63 is an appropriate detection value obtained within the above range, the detection value of the first photo IC 61 is a portion outside the measurement that is not within the above range (for example, + 150 ° ) Is detected.

  Thereby, it can be known that the rotating shaft 3 has been rotated beyond ± 45 ° outside the measurement range. Therefore, by using the output of the third photo IC 63 as a limiter, when the output of the third photo IC 63 shows an appropriate detection value, control is performed to stop the rotation of the rotary shaft 3. Therefore, it is possible to ensure safety by preventing excessive rotation of the rotary shaft 3.

  As described above, the present invention is not limited to the embodiment described above and shown in the drawings, and various modifications can be made without departing from the scope of the invention. For example, in the above-described embodiment, the example in which the rotation angle is detected by rotating the rotation axis within the range of 90 ° (± 45 °) has been described, but it is needless to say that the rotation angle can be set to 90 ° or less. .

DESCRIPTION OF SYMBOLS 1,50,60,70 ... Optical non-contact potentiometer, 2 ... Base member (support member), 3 ... Rotating shaft, 3a ... Small diameter part, 4 ... Light-shielding member, 4b ... Light-shielding part, 5, 65, 66, 67 ... Eccentric rotor (light quantity adjusting unit), 6 ... Light emitting diode (light emitting means), 7 ... Light source holder, 8, 51, 52, 61, 62, 63 ... Photo IC (light receiving means), 9 ... Circuit board, 10 ... Board Holder: 15 ... 1st guide groove, 16 ... 2nd guide groove, 21 ... Axial hole, 53 ... Constant current circuit for LED drive, 54 ... Feedback circuit, E ... Eccentricity amount, X ... 1st direction, X1 ... first reference line, Y ... second direction, Y1 ... second reference line

Claims (6)

A rotating shaft rotatably supported by the support member;
A light shielding member disposed opposite to the rotating shaft;
A light emitting means disposed on one side of a direction intersecting a direction in which the rotating shaft and the light shielding member face each other;
A plurality of light receiving means disposed on the other side of the direction intersecting the direction in which the rotating shaft and the light shielding member face each other and disposed opposite to the light emitting means,
Provided on the rotating shaft is a light amount adjusting unit that changes a gap with the light shielding member according to a rotational position of the rotating shaft ;
At least one light receiving means among the plurality of light receiving means is disposed at a position where the amount of light received does not change regardless of the change in the gap by the light amount adjusting unit,
The other light receiving means of the plurality of light receiving means is arranged at a position where the amount of light received according to the change of the gap by the light amount adjusting unit is changed . A disk-shaped support member;
A rotation shaft that is rotatably supported so as to penetrate a central hole provided in the support member;
A light shielding member provided on the one surface side of the support member so as to face the rotation shaft with a predetermined gap;
A light emitting means disposed on one side of a direction intersecting a direction in which the rotating shaft and the light shielding member face each other on the one surface side of the support member;
A plurality of light receiving means disposed on the other side of the direction intersecting the direction in which the rotating shaft and the light shielding member face each other on the one surface side of the support member, and disposed opposite to the light emitting means,
Provided on the rotating shaft is a light amount adjusting unit that changes a gap with the light shielding member according to a rotational position of the rotating shaft ;
At least one light receiving means among the plurality of light receiving means is disposed at a position where the amount of light received does not change regardless of the change in the gap by the light amount adjusting unit,
The other light receiving means of the plurality of light receiving means is arranged at a position where the amount of light received according to the change of the gap by the light amount adjusting unit is changed . The optical system according to claim 1 or 2, wherein the light amount adjusting unit includes an eccentric cylindrical shaft having an axial hole provided eccentrically with respect to an outer peripheral surface and fitted to the rotating shaft. Non-contact potentiometer. The optical non-contact potentiometer according to claim 1, 2 or 3, wherein a gap between the light amount adjusting unit and the light shielding member is formed to be substantially the same size as the light receiving unit of the light receiving unit. A plurality of the light amount adjusting portions provided in the axial direction of the rotating shaft, the same number as the number of the other light receiving means, with a predetermined gap ;
5. The optical contactless potentiometer according to claim 1, 2, 3, or 4 , wherein each of the other light receiving means is disposed so as to face each of the light amount adjusting sections . The optical non-contact potentiometer according to claim 5, wherein the light amount adjusting units provided at a plurality of locations are provided with their eccentric sides rotated and displaced by 90 degrees from each other.

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