JP2008064710A - Angle detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an angle detector capable of detecting linearly an angle change of an angle detecting object, and capable of enhancing detection precision thereof, in the angle detector using an optical sensor. <P>SOLUTION: This angle detector 1 includes a light projection part 12a and a light receiving part 12b arranged opposedly. Light shielding plates 8a, 8b are interposed to include a variable opening part for changing gradually an aperture, while followed to the motion of the angle change of the angle detecting object, around the center line connecting the light projection part 12a and the light receiving part 12b, as the opening center, between the light projection part 12a and the light receiving part 12b. An angle detecting part 13 finds a changed angle of the angle detecting object, based on a receiving quantity of light from the light projection part 12a received by the light receiving part 12b. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an angle detection device that detects, for example, a rotation angle of a steering wheel of a vehicle.

  Conventionally, as an angle detection device for detecting a rotation angle or a tilt angle of a detection target such as a steering wheel or a shift lever in a vehicle, for example, a light detection type angle detection device using an optical sensor or a magnetic detection type using a magnetic sensor An angle detection device has been proposed.

  In general, in a light detection type angle detection device, a plurality of optical sensors are used, and a slit having a predetermined shape is provided in a shielding plate that shields between a light projecting unit and a light receiving unit of the optical sensor, and the shielding plate is used for light shielding. The angle change of the detection target is detected based on the light receiving pattern of the accompanying optical sensor.

  Further, in the magnetic detection type angle detection device, for example, a relative angle change with a magnet whose angle changes in conjunction with a change in the angle of the detection target is detected by a magnetic sensor, and the angle of the detection target is determined based on the detected value. Change is to be detected.

  Comparing these two types of angle detection devices, the light detection type angle detection device requires a plurality of optical sensors, and detects the angle change based on the light receiving pattern, so only the digital angle change is detected. Therefore, the change in the angle of the detection target cannot be detected linearly. On the other hand, the magnetic detection type angle detection device has a problem that the angle change of the detection target can be detected linearly and resistance to disturbance is low.

Therefore, conventionally, for example, an angle detection device as disclosed in Patent Document 1 has been proposed.
This angle detection device has a structure in which a light shielding plate that rotates following an angle change of an angle detection target is disposed between a light projecting unit and a light receiving unit that constitute an optical sensor. The light shielding plate has a shape in which the radius gradually changes with respect to the center of rotation, and the amount of light received by the light receiving portion increases and decreases linearly with rotation. For this reason, although it is a light detection type angle detection device, it becomes possible to detect a linear angle change of an angle detection target. Further, since it is a light detection type, it has high resistance to disturbance and high detection reliability can be obtained.
JP-A-9-269214

  However, in the angle detection device disclosed in Patent Document 1, for example, as shown in FIG. 6, the light shielding plate 51 has a center O in the directions of arrows F1 and F2 shown in FIG. It rotates as the axis of rotation. Then, as indicated by hatching in the figure, the light receiving part 52 is shielded in order from the outer peripheral part in a manner like a full moon. For this reason, the shielding area of the light receiving portion 52 by the light shielding plate 51 varies very unevenly with respect to the rotation angle of the light shielding plate 51. Therefore, the amount of light received by the light receiving unit 52 is non-uniform with respect to the angle change of the light shielding plate 51. Accordingly, the detected voltage of the light receiving unit 52 has a portion where the variation difference is large and a portion where the variation difference is small depending on the rotational position of the light shielding plate 51. In order to detect a change, a complicated calculation is required, or a map of detection voltage for each angle is required. Therefore, there remains room for improvement as a photodetection type angle detection device capable of linearly detecting an angle change from such a viewpoint.

  The present invention has been made in view of such circumstances, and an object of the present invention is to detect an angle change of an angle detection target linearly in an angle detection apparatus using an optical sensor and to improve detection accuracy. An object of the present invention is to provide an angle detection device that can be realized.

  In order to solve the above-described problem, in the invention according to claim 1, an optical sensor composed of a light projecting unit and a light receiving unit arranged to face each other, and interposed between the light projecting unit and the light receiving unit, an angle A diaphragm mechanism having a variable opening whose opening gradually changes with the center line connecting the light projecting part and the light receiving part as the center of opening following the change in the angle of the detection target, and from the light projecting part by the light receiving part The gist of the present invention is to provide angle detection means for obtaining a change angle of the angle detection object based on the amount of received light.

  According to the above configuration, the opening degree of the variable opening of the aperture mechanism gradually changes following the change in angle of the angle detection target. As a result, since the amount of light received by the light receiving unit changes linearly, the detection value by the light receiving unit also changes linearly. Therefore, it becomes possible to linearly detect the angle change of the angle detection target using the optical sensor. In addition, since the opening of the variable opening gradually changes with the center line connecting the light projecting part and the light receiving part constituting the optical sensor as the center of the opening, the opening of the angle detection target can be easily controlled. be able to. Therefore, the angle change of the angle detection target can be detected with high accuracy.

  According to a second aspect of the present invention, in the angle detection device according to the first aspect, the diaphragm mechanism includes a plurality of light shielding plates that follow the angle change of the angle detection target, and an overlapping amount of the light shielding plates. The gist of the present invention is that the gap generated by the change of the angle becomes the variable opening.

  According to the above configuration, the variable opening is configured by a gap that is generated when the overlapping amount of the plurality of light shielding plates changes. For this reason, a variable opening part can be reliably comprised by this light-shielding plate.

  According to a third aspect of the present invention, in the angle detection device according to the second aspect, the diaphragm mechanism includes the two light shielding plates arranged so that one side portions thereof overlap each other. The gist of the invention is that the one side portion is provided with a notch portion in which the variable opening portion having a substantially diamond shape is formed when they overlap each other.

  According to the above configuration, the diaphragm mechanism includes the two light shielding plates provided with the notches on one side portion that overlaps each other, and the notch portions form a variable opening having a substantially diamond shape. In such a variable opening, the coaxial / similar rhombus becomes larger or smaller as the overlapping amount of the light shielding plates changes, so that it becomes easy to control the opening degree with respect to the angle change of the angle detection target. Therefore, the angle change of the angle detection target can be detected with high accuracy. In addition, since the two light shielding plates constituting the diaphragm mechanism can be configured, the angle detection device can be configured simply.

  According to a fourth aspect of the present invention, in the angle detection device according to any one of the first to third aspects, the aperture mechanism has an opening area of the variable opening with respect to an angle change of the angle detection target. The main point is to increase or decrease the ratio proportionally.

  According to the above configuration, the opening area of the variable opening portion increases or decreases in proportion to the angle change of the angle detection target. For this reason, the change of the detection value by the light receiving unit is constant with respect to the angle change of the angle detection target. Therefore, it becomes possible to detect the angle change of the angle detection target by the optical sensor linearly with high accuracy.

  As described above in detail, according to the present invention, in the angle detection device using the optical sensor, the angle change of the angle detection target can be detected linearly, and the detection accuracy can be improved. A detection device can be provided.

DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment embodying the present invention will be described in detail with reference to FIGS.
As shown in FIGS. 1 and 2, the angle detection device 1 includes an aperture mechanism 2 that is driven by an angle change operation (turning or the like) of an angle detection target (not shown) (for example, a steering shaft in a vehicle). The diaphragm mechanism 2 is disposed in the housing in a state of being supported by four support portions (first to fourth support portions 3a to 3d) fixed to a housing (not shown) or the like.

  The diaphragm mechanism 2 includes a rotating body 4 that rotates in conjunction with an angle detection target, an interlocking shaft portion 5 that extends on the rotational axis of the rotating body 4, and a connection that is connected to the tip of the interlocking shaft portion 5. The bar 6, the working shafts 7a and 7b provided between the interlocking shaft portion 5 and both ends of the connecting bar 6, and a plurality (two in this case) of light-shielding lightly fitted on the working shafts 7a and 7b. And plates (first light shielding plate 8a and second light shielding plate 8b).

Specifically, the rotating body 4 is made of a disk-like object configured by, for example, a gear portion meshed with an angle detection target, and rotates with a change in the angle of the angle detection target.
The interlocking shaft portion 5 has a substantially cylindrical shape, and the base end is fixed so as to be coaxial with the rotation axis O on one surface of the rotating body 4 (the lower surface in FIGS. 1 and 2), and the distal end extends downward. Yes.

  The connecting bar 6 is formed of a substantially rectangular parallelepiped rod-like object extending in a direction orthogonal to the axial center direction of the interlocking shaft portion 5, and a central portion in the longitudinal direction is fixed to the tip of the interlocking shaft portion 5. For this reason, the connecting bar 6 rotates together with the rotating body 4 around a fixed portion with the interlocking shaft portion 5, that is, the rotation axis O of the rotating body 4.

  Each of the action shafts 7a and 7b is formed of a substantially columnar object fixed to the connection bar 6 so that a fixed position of the connection bar 6 with the interlocking shaft portion 5 is a symmetric position. Projecting from the surface opposite to the fixed surface (downward).

  The first light-shielding plate 8 a and the second light-shielding plate 8 b are each constituted by a plate-like object having a substantially rectangular shape in plan view, and are disposed below the connecting bar 6 so that one side portions overlap each other. As also shown in FIGS. 3 (a) to 3 (c), long holes 9a and 9b into which the corresponding action shafts 7a and 7b are loosely fitted are formed at substantially the center of the respective light shielding plates 8a and 8b. ing. Further, notches 10a and 10b constituting the variable opening 10 made of a square-shaped rhombus are provided on one side of the light shielding plates 8a and 8b that overlap each other. That is, these notches 10a and 10b are formed by right-angled isosceles triangle-like notches provided at locations corresponding to each other on one side portion overlapping each other in each light shielding plate 8a and 8b.

  The first light shielding plate 8a is supported by the first support portion 3a and the second support portion 3b on both sides of the first light shielding plate 8a on the side perpendicular to the one side where the notch 10a is provided, and the second light shielding plate. Both side portions on the side perpendicular to the one side portion provided with the notch portion 10b in 8b are supported by the third support portion 3c and the fourth support portion 3d. Specifically, guide grooves 11 that coincide with the side portions of the respective light shielding plates 8a and 8b are formed in the surfaces facing each other in the support portions 3a to 3d, and the light shielding plates 8a and 8b corresponding to the guide grooves 11 are provided. The light shielding plates 8a and 8b are in a state of being supported by the first to fourth support portions 3a to 3d. For this reason, when the connecting bar 6 rotates together with the rotating body 4, the action shafts 7 a, 7 b move in the long holes 9 a, 9 b, so that the light shielding plates 8 a, 8 b move along the guide grooves 11. It moves linearly in the facing direction (the directions of arrows F1 and F2 shown in FIGS. 3A to 3C). As the light shielding plates 8a and 8b move, the overlapping amount changes, and the opening area of the variable opening 10 formed by the notches 10a and 10b increases or decreases. More specifically, for example, as schematically shown in FIG. 4, the variable opening 10 has the same rhombus shape centered on the rotation axis O of the rotating body 4 as the light shielding plates 8 a and 8 b move. As a result, the opening area increases or decreases.

  As shown in FIGS. 3A to 3C, in the present embodiment, the long holes 9a and 9b have a preset curved shape. Specifically, each of the long holes 9 a and 9 b has a shape that is point-symmetric with respect to the rotational axis O, and the opening area of the variable opening 10 increases and decreases proportionally with respect to the change in the angle of the rotating body 4. As described above, a shape for adjusting the amount of movement of each light shielding plate 8a, 8b is formed. In other words, each of the long holes 9a and 9b has a shape that adjusts the amount of movement of each of the light shielding plates 8a and 8b so that the increase / decrease rate of the opening area with respect to the angle change rate of the rotating body 4 is constant.

  By the way, as shown in FIG.1 and FIG.2, the light projection part 12a which comprises the optical sensor 12 is being fixed to the location corresponding to the interlocking shaft part 5 in the lower surface of the connection bar 6. FIG. The light projecting unit 12a is composed of a directional light source such as an LED or a semiconductor laser, and is fixed so as to emit light in the direction of the light shielding plates 8a and 8b. A light receiving portion 12b constituting the optical sensor 12 is disposed below the light shielding plates 8a and 8b at a location facing the light projecting portion 12a. The light receiving unit 12b is mounted on a substrate (not shown) fixed to the first to fourth support units 3a to 3d, the housing, and the like, and detects the amount of light received from the light projecting unit 12a. . For this reason, each light shielding plate 8a, 8b is in a state of being interposed between the light projecting unit 12a and the light receiving unit 12b. Further, the opening of the variable opening 10 gradually changes with the center line (rotation axis O) connecting the light projecting part 12a and the light receiving part 12b as the center of opening.

  The light projecting unit 12a and the light receiving unit 12b are electrically connected to an angle detecting unit 13 as an angle detecting unit mounted on the substrate. The light projecting unit 12 a operates based on a control signal from the angle detection unit 13, and the light receiving unit 12 b converts the amount of received light into a voltage and outputs the voltage to the angle detection unit 13. The angle detection unit 13 performs light emission control of the light projecting unit 12a and obtains the rotation angle of the rotating body 4, that is, the change angle of the angle detection target, based on the voltage value input from the light receiving unit 12b.

Next, the operation of the angle detection device 1 configured as described above will be described in more detail.
As shown in FIG. 3A, in the state where the connecting bar 6 is located at the intermediate position (neutral position) in the rotatable range (rotation allowable angle), each light shielding plate 8a, 8b has a variable opening. The opening area of 10 is positioned so as to be half the difference between the maximum opening area Smax and the minimum opening area Smin.

  In this state, the connecting bar 6 can be rotated in the directions of arrows R1 and R2, and the light shielding plates 8a and 8b linearly move in the directions of arrows F1 and F2 as the connecting bar 6 rotates.

  Specifically, as shown in FIG. 3B, when the connecting bar 6 rotates in the direction of arrow R1, the first light shielding plate 8a moves in the direction of arrow F2, and the second light shielding plate 8b moves in the direction of arrow F1. The amount of overlap increases and the opening area of the variable opening 10 decreases. When the connecting bar 6 is rotated to the limit of rotation in the direction of the arrow R1, the variable opening 10 is just closed, and “minimum opening area Smin = 0”.

  On the other hand, as shown in FIG. 3C, when the connecting bar 6 rotates in the direction of the arrow R2, the first light shielding plate 8a moves in the direction of the arrow F1 and the second light shielding plate 8b moves in the direction of the arrow F2 and overlaps each other. The amount decreases and the opening area of the variable opening 10 increases. When the connecting bar 6 is rotated to the limit of rotation in the direction of the arrow R2, the side edges of the light shielding plates 8a and 8b are aligned with each other so that the variable opening 10 is fully opened. The maximum opening area Smax.

  And among the light radiated | emitted from the light projection part 12a, while the light which passed the variable opening part 10 is detected by the light-receiving part 12b, the detection voltage according to the received light quantity is input into the angle detection part 13, The rotation angle of the rotating body 4, that is, the change angle of the angle detection target is obtained by the angle detection unit 13.

  As described above, each of the long holes 9a and 9b provided in each of the light shielding plates 8a and 8b is configured so that the opening area of the variable opening 10 increases and decreases in proportion to the change in the angle of the rotating body 4. It has a shape for adjusting the amount of movement of each light shielding plate 8a, 8b. For this reason, as shown in FIG. 5, the rotation angle of the rotating body 4 and the opening area of the variable opening 10 are in a proportional relationship. Further, since the opening of the variable opening 10 gradually changes with the center line (here, the rotation axis O) connecting the light projecting part 12a and the light receiving part 12b as the opening center, the amount of light passing through the variable opening 10 Is also substantially proportional to the aperture area, the relationship between the aperture area and the detection voltage by the light receiving portion 12b is also proportional. Therefore, the rotation angle of the rotating body 4 and the detected voltage are in a proportional relationship. Therefore, the angle detection unit 13 can detect the angle change of the angle detection target linearly and easily and reliably based on the detection voltage input from the light receiving unit 12b. In addition, since the rotation angle of the rotating body 4 and the detection voltage are in a proportional relationship, it is possible to detect the angle change of the angle detection target with high resolution and high accuracy.

Therefore, according to the present embodiment, the following effects can be obtained.
(1) The degree of opening of the variable opening 10 of the diaphragm mechanism 2 gradually changes following the change in angle of the angle detection target. As a result, the amount of light received by the light receiving unit 12b changes linearly, and the detection value by the light receiving unit 12b also changes linearly. Therefore, the angle change of the angle detection target can be detected linearly using the optical sensor 12. Further, since the opening of the variable opening 10 gradually changes with the center line connecting the light projecting unit 12a and the light receiving unit 12b constituting the optical sensor 12 as the center of the opening, the opening control for the angle change of the angle detection target is performed. Can be easily performed. Therefore, the angle change of the angle detection target can be detected with high accuracy.

  (2) The variable opening 10 is formed by notches 10a and 10b provided on one side of the two light shielding plates 8a and 8b that overlap each other, and changes in the amount of overlap between the light shielding plates 8a and 8b. As a result, the coaxial and isomorphic diamonds grow larger and smaller. For this reason, the control of the opening degree with respect to the angle change of the angle detection target is surely facilitated. Therefore, the angle detector 13 can detect the angle change of the angle detection target with high accuracy. In addition, since the light shielding plate constituting the diaphragm mechanism 2 can be composed of two sheets, the angle detection device 1 can be configured simply.

  (3) The opening area of the variable opening 10 increases or decreases in proportion to the angle change of the angle detection target. For this reason, the change in the detected voltage value by the light receiving unit 12b is constant with respect to the angle change of the angle detection target. Therefore, the angle change of the angle detection target by the optical sensor 12 can be detected linearly with high accuracy.

  (4) The effect of (3) can be obtained only by devising the shape of the long holes 9a and 9b. That is, the effect (3) can be reliably obtained with a simple configuration. For this reason, the angle detection device 1 can be easily designed and manufactured, and the number of components does not increase excessively.

In addition, you may change embodiment of this invention as follows.
-The light shielding plate is not limited to being composed of two sheets (first light shielding plate 8a and second light shielding plate 8b), and for example, there are three or more light shielding plates such as a diaphragm mechanism used in a general camera or the like. You may be comprised by the light-shielding plate. If it does in this way, it can be set as the substantially circular variable opening part 10. FIG.

  The notches 10a and 10b provided in the respective light shielding plates 8a and 8b do not necessarily have to have a shape forming the rhomboid variable opening 10, for example, a substantially semi-elliptical shape, The shape of the polygonal variable opening 10 may be a shape.

  The change in the angle of the rotating body 4 and the increase / decrease in the opening area of the variable opening 10 do not necessarily have a proportional relationship. That is, it is only necessary that the opening area of the variable opening 10 is always increased or decreased with respect to a change in the angle of the rotating body 4 in one direction.

  -You may comprise each long hole 9a, 9b linearly. Even in this case, the rotation angle of the rotating body 4 and the increase / decrease of the opening area of the variable opening 10 are close to a proportional relationship. For this reason, although it is not as much as the said embodiment, compared with the angle detection apparatus of patent document 1 described by the said background art, the angle change of an angle detection object can be detected with high precision. Moreover, when it changes in this way, design of each long hole 9a, 9b becomes easy.

  The light projecting unit 12a and the light receiving unit 12b constituting the optical sensor 12 and the opening center of the variable opening 10 do not necessarily have to be arranged on the rotation axis O of the rotating body 4, and the light projecting unit What is necessary is just to satisfy | fill the conditions that the opening center of the variable opening part 10 is located on the centerline which connects 12a and the light-receiving part 12b.

  -The angle detection target is not limited to a rotating body such as a steering shaft. For example, any accelerator can be used as long as it causes an angle change and needs to be detected. is there.

Next, in addition to the technical ideas described in the claims, the technical ideas grasped by the embodiment described above are listed below.
(1) In the angle detection device according to claim 2 or 3, the variable opening is set so that the opening having the same shape is concentrically large or small according to an angle change of the angle detection target. Being. According to the technical idea described in (1), it is possible to easily control the increase / decrease ratio of the opening area of the variable opening with respect to the angle change of the angle detection target.

The perspective view which shows schematic structure of the angle detection apparatus of one Embodiment of this invention. The front view which shows typically schematic structure of the angle detection apparatus of the embodiment. (A)-(c) is a top view which shows roughly the operation example of the embodiment. The figure which shows typically operation | movement of the variable opening part of the angle detection apparatus of the embodiment. The graph which shows the relationship between the angle change of an angle detection object, and the opening area of a variable opening part. The figure which shows typically the angle detection principle of the conventional optical sensor type angle detection apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Angle detection apparatus, 2 ... Diaphragm mechanism, 8a, 8b ... Light-shielding plate, 10 ... Variable opening part, 10a, 10b ... Notch part, 12 ... Optical sensor, 12a ... Light projection part, 12b ... Light-receiving part, 13 ... An angle detector as an angle detector.

Claims (4)

An optical sensor composed of a light projecting unit and a light receiving unit disposed opposite to each other;
A variable opening that is interposed between the light projecting unit and the light receiving unit, and whose opening degree gradually changes with a center line that connects the light projecting unit and the light receiving unit being driven by an angle change of an angle detection target An aperture mechanism having a portion;
An angle detection apparatus comprising: an angle detection unit that obtains a change angle of the angle detection target based on an amount of light received from the light projecting unit by the light receiving unit.   The diaphragm mechanism includes a plurality of light shielding plates that follow an angle change of the angle detection target, and a gap generated when the amount of overlap between the light shielding plates changes serves as the variable opening. Item 2. The angle detection device according to Item 1.   The diaphragm mechanism includes two light shielding plates arranged so that one side portions thereof overlap each other, and the one side portion of the light shielding plates has a substantially rhombic shape when they overlap each other. The angle detection device according to claim 2, wherein a notch portion is provided.   The angle detection device according to claim 1, wherein the aperture mechanism proportionally increases or decreases the opening area of the variable opening with respect to an angle change of the angle detection target. .

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