JPH02191584A - Device for preventing contamination of optical sensor - Google Patents

Abstract

PURPOSE:To prevent the adhesion of contaminations, such as water drops and dust, by traveling onto the light transmission surface of the optical sensor by mounting a perpendicular grid- or honeycomb-shaped porous body (filter) onto the light transmission surface. CONSTITUTION:One end of the porous body (filter) 8 which is approximately perpendicular to the light transmission surface 1 of the optical sensor is made into the grid or honeycomb or other shape and has a prescribed height in a vehicle 2 having the vertical light transmission surface turned downward is mounted onto the light transmission surface 1 of the above-mentioned optical sensor. Even if the contaminations 9, such as water drops and dust, arrive at the optical sensor of the above-mentioned constitution according to the movement of the vehicle 2, the light transmission surface 1 side of the filter 8 is closed and, therefore, the air flow is shut off and the contaminations 9 are forced to stick to the side wall surfaces of the respective segment frames of the filter 8 and are thereby prevented from arriving at the light transmission surface 1.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to a contamination prevention device for optical sensors used in locations with poor environments where contaminants such as water droplets and dust fly, such as under the floor of a railway vehicle. be.

[Conventional technology]

FIG. 3 is a side sectional view showing a conventional contamination prevention device for an optical sensor of this kind. In the figure, (1) is an optical sensor installed under the floor of the car body (2) of a railway vehicle, and the figure shows its light receiving part.
a) is installed so that it faces downward toward the raceway surface. This optical sensor consists of a light emitting part and a light receiving part. For example, the light emitting part emits a light beam toward the track surface, and the reflected light is received by the light receiving part, thereby determining the vehicle speed, vehicle height position, etc. It is used for the purpose of detecting. (3) is an air purge nozzle as a dirt prevention device attached to the lower surface of the light receiving part (1) so as to surround the protective glass (1a). Compressed air is sent as shown by arrow (5) to form an air curtain as shown by arrow (5).

By forming this air curtain (5), the protective glass (1
This is to prevent the attenuation of the amount of light by preventing the adhesion to a). Note that the arrow (6) indicates the direction of movement of the vehicle body (2), and the arrow (7) indicates the moving direction of the vehicle body (2).
) indicates the light beam incident on the light receiving section (January).

[Problem to be solved by the invention]

Conventional optical sensor contamination prevention devices are configured as shown below, so an air compressor or the like is required to constantly supply compressed air, and an air purge nozzle (3) is also required for the flow of this compressed air. Since it requires sufficient strength to withstand, there is a problem in that the device as a whole becomes expensive, large and heavy.

This invention has been made to solve the above-mentioned problems, and aims to provide a compact and lightweight optical sensor stain prevention device without requiring an air compressor or the like.

[Means to solve the problem]

A contamination prevention device for an optical sensor according to the present invention is a porous columnar body having a predetermined height and substantially perpendicular to the light transmitting surface of the optical sensor. It is mounted on a surface.

[For production]

When the vehicle moves and dirt such as water droplets and dust fly away, the light-transmitting surface side of each division frame that makes up the porous columnar body is closed, so the flow of air toward the light-transmitting surface is blocked. Therefore, the soil and manure dirt adheres to the side wall surface of each compartment frame and almost never reaches the light transmitting surface. [Example] Fig. 1 is a side cross-sectional view showing a dirt prevention device for an optical sensor according to an embodiment of the present invention. , FIG. 2 is a plan view of FIG. 1 viewed from below. In the figure, (i) (la)
+21 (6) is the same as before. (8) is a lattice filter in the form of a porous columnar body constructed by combining thin metal plates such as aluminum in a lattice shape. (
1a) is hermetically fixed to a plane including the surface of 1a).

Here, when the vehicle (2) runs in the direction of the arrow (6),
Dirt (9) such as water droplets and dust flies into the light receiving section (1), but inside each division frame (8a) of the lattice filter (8), the upper end is airtight due to the lower surface of the light receiving section (1). Since it is closed, air pollution caused by traveling does not reach the upper end of the partition frame (8a). Therefore, as shown by the arrow a0 in FIG. It sticks to the wall surface and then either continues to stick or falls downward due to its own weight or vibration.As mentioned above, dirt (9) hardly sticks to the protective glass (1a), and the amount of light received decreases due to the dirt adhesion. Attenuation is prevented.

The height dimension of the lattice filter (8) is determined in consideration of the speed of the vehicle (2), the type and size of the expected dirt (9), etc. The same applies to the size of one segment of the grid.

In the above embodiment, the porous columnar body was made of aluminum plate and had a lattice shape, but various materials other than aluminum plate may be used, and the shape may be various, such as a so-called honeycomb shape. It is possible to adopt various shapes consisting of dividing frames.

Furthermore, although the above embodiment was directed to preventing contamination of the light receiving section (1) of an optical sensor, the present invention may be similarly applied to a light emitting section (not shown).

〔Effect of the invention〕

As described above, in the present invention, one end of the porous columnar body having a predetermined height and substantially perpendicular to the light transmitting surface of the optical sensor is attached on the light transmitting surface, and air is removed as the vehicle moves. Since the flow hardly reaches the light transmitting surface, there is no need for an air compressor, etc., making it compact and compact.
The lightweight structure prevents flying dirt from adhering to it.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view showing a contamination prevention device for an optical sensor according to an embodiment of the present invention, FIG. 2 is a plan view of FIG. 1 viewed from below, and FIG. 3 is a conventional contamination prevention device for an optical sensor. FIG. In the figure, (1) is the light receiving part as an optical sensor, (1a) is the protective glass as the light transmitting surface, (2) is the vehicle, (6) is the direction of movement of the vehicle, and (8) is the porous columnar body. The lattice filter (9) is dirt. Note that the same reference numerals in each figure indicate the same or corresponding parts. Agent: Masuo Oiwa, patent attorney

Claims (1)

[Scope of Claims] An optical sensor is placed in front of the light transmitting surface of an optical sensor installed in a vehicle with the light transmitting surface facing almost vertically downward, and dirt such as water droplets and dust flying in as the vehicle moves is directed onto the light transmitting surface. In the device for preventing adhesion, one end in the height direction of a porous columnar body such as a lattice-shaped or honeycomb-shaped body having a predetermined height and substantially perpendicular to the light-transmitting surface is attached on the light-transmitting surface. An optical sensor dirt prevention device featuring: