JPH04286913A - Optical inclination sensor - Google Patents

Abstract

PURPOSE:To obtain an optical inclination sensor which can accurately detect up to an extremely small angle and has a long service life. CONSTITUTION:An optical inclination sensor has a light emitting element 2 fixed to a base 14, a curved surface 402 which is constantly facing the light emitting element 2 and a plane 403 which is constantly facing the curved surface. The sensor has a light condensing means 4 which is rotatably supported by a shaft 9 so that light from the light emitting element 2 is reflected by the curved surface 402 and the plane 403 and condensed to a predetermined position wherein the curved surface 402 and the plane 403 move along an arc orbit with the shaft 9 as the center, and an arc-shaped light receiving part which is placed on the orbit drawn by movement of the predetermined position where the light reflected by the light condensing means 4 is condensed according the movement of the light condensing means 4 and which is applied with the light from the light emitting element 2. A light detecting means which generates different outputs according to the positions of the light applied to the light receiving part is also provided.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical tilt sensor for detecting tilt of a vehicle in one direction.

0002

2. Description of the Related Art Conventionally, as a tilt sensor for detecting tilt in one direction, there is a tilt sensor using a rotary and sliding type potentiometer 21 as shown in FIG. This is constructed by fixing a weight 22 to the tip of a shaft 24 that is provided on a rotating shaft 23 of a potentiometer 21 and extends in the radial direction of the rotating shaft 23, and is configured such that the shaft 24 always points in the vertical direction. Therefore, when the vehicle tilts, the output of the potentiometer 21 changes, so that the tilt of the vehicle can be detected.

0003

[Problems to be Solved by the Invention] However, as described above, in a tilt sensor using a potentiometer, it is difficult to detect minute tilt angles due to the frictional force that acts between the contacts of the potentiometer, and hysteresis occurs in the output. There is a problem with this. Furthermore, since the contacts wear out, a long life cannot be expected.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an optical tilt sensor that can accurately detect even minute angles and can be expected to have a long life.

[0005]

[Means for Solving the Problems] In order to achieve the above object, the optical tilt sensor of the present invention includes a light emitting element fixed to a base, a first reflecting surface always facing the light emitting element, The first reflecting surface is rotatably supported by a shaft so as to reflect the light from the light emitting element on the first reflecting surface and condense the light at a predetermined position, and the first reflecting surface is moved toward the shaft according to the inclination of the base. a light condensing means that moves along an arcuate locus centered at , and the predetermined position where the light reflected by the first reflecting surface of the condensing means is condensed is the first
A light receiving part arranged on a trajectory drawn according to the movement of a reflecting surface of the light emitting means and irradiated with light from the light emitting means, and generating different outputs depending on the position of the light irradiated to the light receiving part. Detecting means.

[0006]

[Operation and effects of the invention] By having the above configuration,
The condensing means guides the light from the light emitting means to different positions of the light receiving means according to the inclination of the non-detection object, and detects the inclination angle of the non-detection object.

According to the present invention, since the inclination angle is not detected by the displacement of the contact position of the fixed side contact and the movable side contact as in the past, there is no friction between the contacts, and the inclination angle is not detected depending on the inclination of the non-detecting object. This has the advantage that the tilt angle can be detected steplessly with high accuracy and a long life can be achieved.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the optical tilt sensor according to the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 1 is a sectional view of the optical tilt sensor of the present invention, and FIG. 2 is a perspective view showing the assembled state of the main parts of the embodiment shown in FIG.

In the figure, reference numeral 1 denotes a resin member, in which a light emitting element support part 101 and a light receiving element support part 102 are integrally molded. The light emitting element support part 101 has a cylindrical shape, and the LED 2, which is a light emitting element, is inserted from the base side of the light emitting element support part 101. The light receiving element support part 102 has a rectangular opening 103
The light receiving element 3 is inserted so that the light receiving portion 301 of the light receiving element 3 can be confirmed through the opening 103. As the light receiving element 3, for example, one disclosed in Japanese Patent Application Laid-Open No. 59-229116 is used. In other words, the light receiving section 30
Reference numeral 1 denotes an arc-shaped photoconductive film, and when light reaches this photoconductive film, the resistance value of only the portion that receives the light decreases due to the photoelectric effect. The configuration is such that the voltage taken out to the terminal 302 changes depending on the position where the light is irradiated. The photoconductive film is formed as an arc centered on the axis of the shaft 9 in the assembled state as shown in FIG.

Reference numeral 4 denotes a prism serving as a light condensing means, which guides the light from the light emitting element 2 to the light receiving section 301 of the light receiving element 3. The shape of the prism 4 is shown in FIG. This prism 4 has a first reflective surface 402 that is a spherical surface and a second reflective surface 403 that is a flat surface. Here, it is preferable to apply an anti-reflection coating to the entrance surface of the prism 4 and a mirror coating to the reflection surface. As shown in FIG. 5, this prism 4 is fixed to a fan-shaped metal plate 10. The metal plate 10 is made of a non-magnetic metal with high electrical conductivity, such as aluminum.

The first plate 5 is made of an iron plate having an L-shaped cross section. This first plate 5 is fixed to the base 14 with screws 12 through screw holes 501. A cylindrical recess 503 is located approximately at the center of the plane portion 502 perpendicular to the base 14.
A disc-shaped magnet 7 is fixed with adhesive. The second plate 6 is also made of an iron plate having an L-shaped cross section like the first plate 5, and is fixed to the base 14 with screws 13 through two screw holes 601. An opening 603 corresponding to the shapes of the light emitting element support 101 and the light receiving element support 102 of the resin member 1 is provided in a flat surface 602 that is perpendicular to the base 14 . Note that both plates 5 and 6 are provided with bearings 504 and 604, respectively.

Reference numeral 8 designates a printed circuit board, which includes a first hole 801 into which the electrode 201 of the light emitting element 2 is inserted, a third hole 802 into which the terminal 302 of the light receiving element 3 is inserted, and four holes in the resin member 1. The third hole 80 into which the pin 104 of No. 1 is inserted
3, and the wiring board of this printed circuit board 8 (not shown)
three fourth holes 804 for inserting wires connected to the
has been established.

The shaft 9 has bearings 5 on both plates 5 and 6.
04, 604, and the metal plate 10 to which the prism 4 is fixed is fixed to this shaft 9 and rotates together with the shaft 9. A cover 11 prevents light from entering the light receiving element 3 from the outside.

The optical tilt sensor having the above structure first includes a light emitting element support part 101 and a light receiving element support part 1 of the resin member 1.
A light emitting element 2 and a light receiving element 3 are respectively assembled to 02. At this time, these light emitting element 2 and light receiving element 3 are fixed using adhesive or the like. Next, this resin member 1 is assembled to the second plate 6. At this time, the light emitting element support part 101 and the light receiving element support part 102 are inserted into the opening 60 of the second plate 6.
3, and the two second pins 105 are passed through the holes 605. Then, as shown in FIG. 3, the resin member 1 is fixed to the plate 6 by deforming the tip of the second pin 105 through the hole 605 by heat and caulking.

As shown in FIGS. 1 to 4, the printed circuit board 8 has the electrode 201 of the light emitting element 2 in the first hole 801, the terminal 302 of the light receiving element 3 in the second hole 802, and the terminal 302 of the light receiving element 3 in the second hole 802. The second pins 104 of the resin member 1 are assembled to correspond to the holes 803, respectively. The wire 15 is inserted into the fourth hole 804. As shown in FIG.
is fixed to the resin member 1. Electrode 20 of light emitting element 2
1. Terminal 302 of light receiving element 3 and wire 15
are each inserted into the printed circuit board 8 and then soldered to the wiring board of the printed circuit board 8 to be fixed to the printed circuit board 8 and to establish electrical continuity.

The optical tilt sensor described above is used by being fixed to, for example, a vehicle via a bracket (not shown). At that time, the bracket 14 is installed so that the bottom surface (H surface) in FIG. 1 is horizontal when the vehicle is horizontal. To explain the operation of the inclination sensor when the vehicle is horizontal, light from the light emitting element 2 is incident perpendicularly to the front surface 401 from the point J of the front surface 401 of the prism 4, as shown by the dashed line I in FIG. . This light is reflected downward by the first reflective surface 402, then reflected toward the front surface 401 by the second reflective surface 403, and is irradiated from point K on the front surface 401. Then, it reaches point L (FIG. 6) on the light-receiving surface of the light-receiving element 3 placed in front. The resistance of the light-receiving element 3 at the L point decreases, and an output corresponding to that position detects that the vehicle is horizontal.

When the vehicle tilts, the prism 3 supported by the shaft 9 swings. At this time, an eddy current due to the magnet 5 flows through the metal plate 10, and a braking force acts on the metal plate 10.
The prism 4 stands still while being tilted by the same angle as the vehicle's tilt angle. When the prism 4 is tilted with respect to the base 14, the incident position of the light from the light emitting element 2 to the prism 4 is as follows.
The prism 4 moves along an arcuate trajectory f centered on the pivot point e (axis center of the shaft 9). Here, it is assumed that the light from the light emitting element 2 is incident from the point M on the front surface 401 of the prism 4, as shown by the two-dot chain line II in FIG. This light is irradiated again from point P on the front surface 401 via the first and second reflective surfaces 402 and 403, and is then irradiated from point P on the light receiving element 3 (FIG. 6).
reach. Then, for the above-mentioned horizontal state, the light receiving element 3
The resistance at the N point of the sensor decreases, and the output changes accordingly, making it possible to detect the inclination of the vehicle.

Point G in the figure indicates the focal point, and the prism 4
The structure is such that light that is perpendicularly incident on the front surface 401 and reflected by the first reflecting surface is collected at this point G. The light receiving section 301 of the light receiving element 3 is arranged at a position corresponding to this point G.

(Second Embodiment) FIG. 8 shows the shape of a prism 4 constituting the light condensing means of the second embodiment, and FIG. 9 shows the developed shape of this prism 4. This prism 4 has two convex lens parts with different diameters, and as shown in FIG. After being reflected by the surface 403, it is irradiated from a convex lens portion with a curvature R2. As in the first embodiment, the lens shape is determined so that the light is focused on the light receiving surface of the light receiving element 3. As mentioned above, since the prism 4 of the second embodiment is provided with a lens portion, the light from the light emitting element 2 is condensed and the light reaching the light receiving surface of the light receiving element 3 is smaller than that of the first embodiment. The cross-sectional area can be reduced, and accuracy can be further improved.

(Third Embodiment) FIG. 10 shows a condensing means of a third embodiment. In the first and second embodiments described above, the prism 4 is used as a condensing means, but in the third embodiment, a resin member having a mirror surface is used. The configuration is the same as in the first embodiment, with a first reflecting surface 402 being a curved surface and a second reflecting surface 402 being a flat surface.
It has a reflective surface 403 of. According to the third embodiment, the condensing means can be manufactured by molding the resin member as shown in FIG. 10 and forming the first and second reflective surfaces by mirror coating. It has the advantage of being easy to manufacture and lightweight.

As described above, the light from the light emitting element reaches different locations on the light receiving surface of the light receiving element depending on the inclination of the vehicle, and the light detection means outputs different output signals depending on the inclination of the vehicle. Since the tilt angle of the vehicle is detected optically and there is no contact part, there is no friction in the contact part and it is possible to reliably detect the tilt angle of the vehicle. At the same time, long life can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the configuration of an embodiment of the optical tilt sensor of the present invention.

FIG. 2 is a perspective view showing the configuration of essential parts of the above embodiment.

FIG. 3 is a cross-sectional view showing in detail the assembled state of the first plate, the resin member, and the printed circuit board.

FIG. 4 is a perspective view showing the configuration of a photodetecting means.

FIG. 5 is a front view showing a prism and a metal member constituting a light guiding means.

FIG. 6 is a front view showing the light-receiving surface of the light-receiving element.

FIG. 7 is a diagram showing the shape of a prism constituting the light condensing means of the first embodiment, in which (a) is a perspective view, (b) is a cross-sectional view, and (c) is a perspective view;
) shows the front view of each.

FIG. 8 is a diagram showing the shape of a prism constituting a light condensing means in a second embodiment, in which (a) is a perspective view, (b) is a sectional view, and (c) is a perspective view;
) shows the front view of each.

FIG. 9 is a plan view showing the developed shape of a prism constituting the light condensing means of the second embodiment.

FIG. 10 is a sectional view showing a resin member having a mirror surface and forming a condensing means in a third embodiment.

FIG. 11 is a diagram showing an example of a conventional tilt sensor;
A) shows a front view, and (b) shows a side view.

[Explanation of symbols]

2. LED that serves as a light emitting element 3. Light-receiving element constituting the light-detecting means 4. Prism serving as light guiding means 5 First plate 6 Second plate 9 Shaft

Claims (4)

[Claims] Claim 1: A light emitting element fixed to a base;
A first reflecting surface always facing the light emitting element is rotatably supported by a shaft so that the light from the light emitting element is reflected by the first reflecting surface and condensed at a predetermined position. a light condensing means in which the first reflective surface moves along an arcuate trajectory centered on the shaft in accordance with the inclination of the base; The predetermined position on which the light is focused has a light receiving part arranged on a trajectory drawn according to the movement of the first reflecting surface and irradiated with light from the light emitting means, and the light receiving part is irradiated with light. An optical tilt sensor comprising: a light detection means that generates different outputs depending on the position of the sensor. 2. A first plate fixed to a base and to which a light emitting element is fixed; a second plate fixed to the base so as to face the first plate; a shaft provided between the two plates and on the first and second plates; a first reflective surface always facing the light emitting element; and a second reflective surface always facing the curved surface. and directs the light from the light emitting element to the first
and is rotatably supported by the shaft so as to reflect the light in the axial direction of the shaft via a second reflecting surface and condense it at a predetermined position, and the first and second a light condensing means whose reflective surface moves along an arcuate locus centered on the shaft; and the predetermined position where the light reflected via the first and second reflective surfaces of the condensing means is condensed. has an arc-shaped light receiving section arranged on a trajectory drawn according to the movement of the first and second reflecting surfaces and irradiated with light from the light emitting means, and the position of the light irradiated onto the light receiving section. An optical tilt sensor comprising: a light detection means that generates different outputs depending on the angle of the light; 3. The optical tilt sensor according to claim 1, wherein the light condensing means is a prism. 4. The optical tilt sensor according to claim 1, wherein the first reflecting surface of the light condensing means is constituted by a concave mirror.