JPS6218060Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a reflective photoelectric switch.

[Prior art and its problems]

A conventional reflective photoelectric switch is shown in FIG.

In FIG. 3, there is shown a reflection type photoelectric switch 1, and this reflection type photoelectric switch 1 includes a light emitting element 11,
It is composed of a light receiving element 12, an electronic circuit 13, and the like.

Details of the electronic circuit 13 are not shown, but include an oscillation circuit for driving the light emitting element 11 and a light receiving element 1.
2, a detection circuit that detects the output of this AC amplifier circuit, an amplifier circuit that amplifies the output of this detection circuit, a switching circuit that is driven by the output of this amplifier circuit, etc. There is. Then, the projected light from the light projecting element 11 is reflected by the reflector, and this reflected light is received and detected by the light receiving element 12 to operate a switching circuit, thereby turning on/off a controlled device such as a relay (not shown).
This is to control off. The cable 14 is for transmitting the output of the switching circuit to a controlled device such as a relay provided outside the case, and for supplying external power to the electronic circuit.

Then, the above-mentioned light emitting element 11 and light receiving element 1
2. The electronic circuit 13 is arranged on the printed circuit board 16. The case 15 has an opening 15a on a predetermined surface thereof.
This opening 15a is closed with a cover 17 via a packing 18.

The cover 17 has a light projecting lens 17a and a light receiving lens 17b integrally molded with resin. Holes are drilled in the four corners of the printed circuit board 16, and screw holes corresponding to these holes are provided in the case 15.
It is located on the side.

Then, on the printed circuit board 16, the light emitting element 11,
After incorporating the light receiving element 12, electronic circuit 13, etc.,
The printed circuit board 16 is stored in the case 15,
After pulling out the cable 14 from a hole provided on the side of the case, the four corners of the printed circuit board 16 are fixed with screws 3. Thereafter, the light shielding member 2 is inserted along the guide provided in the case 15, and then the gasket 18 is inserted into the upper flange 17e of the cover 17, and the cover 17 is inserted into the opening 1 of the case 15.
5a is occluded.

In this way, the reflective photoelectric switch 1 is assembled, but at this time, the light emitting element 11, the light receiving element 1
2 are attached at positions corresponding to the light projecting lens 17a and the light receiving lens 17b, respectively.

However, the optical axes of the light emitting element 11 and the light receiving element 12 are influenced by variations in the dimensions of the holes at the four corners of the printed circuit board 16 and the dimensions of the screw holes provided in the case 15. Further, the light emitting lens 17a and the light receiving lens 17b are affected by the looseness between the cover 17 and the case 15. There is a problem in that the optical axes of the light emitting element 11 and the light receiving element 12 are misaligned with the light emitting lens 17a and the light receiving lens 17b, and the detection area varies depending on the product.

Furthermore, there is a problem that the large number of parts makes assembly difficult and time-consuming.

[Purpose of invention]

The present invention was made in view of the above points,
To provide a reflective photoelectric switch that has a small number of parts, is easy to assemble, and is hard to misalign the optical axes of a light projecting element, a light receiving element, a light projecting lens, and a light receiving lens.

[Structure and effect of the idea]

The present invention includes a light projecting element for projecting light onto an object to be detected, a light receiving element for receiving the projected light reflected by the object to be detected, and an electronic device for processing the output signal of the light receiving element. A printed circuit board on which a circuit is mounted, a case for housing the light emitting element, the light receiving element, and the printed circuit board, and a light emitting lens and a light receiving lens disposed facing the light emitting element and the light receiving element, respectively. and a cover that is integrally formed and closes an opening of the case, wherein the reflective photoelectric switch includes a cover that is integrally formed with a cover that closes an opening of the case, and a cover that is integrally protruded from the cover between the light-emitting lens and the light-receiver lens, and that the printed circuit board is integrally formed with the cover. This is a reflective photoelectric switch characterized by having a positioning protrusion.

With the above configuration, in the present invention, the protrusions for positioning the lens and the printed circuit board are integrally formed on the cover, so the projecting lens, the receiving lens, the protrusions for positioning the printed circuit board, and the cover are integrated into one piece. The number of points is reduced and assembly work becomes easier. Furthermore, since a protrusion for positioning the printed circuit board is provided between the light emitting lens and the light receiving lens to position the printed circuit board, the optical axis of the light emitting element and light receiving element mounted on the printed circuit board and the light emitting The optical axes of the lens and the light-receiving lens can be aligned with high precision, and there is an effect that variations in the detection area are eliminated.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on FIGS. 1 and 2.

The cover 17 has a light projecting lens 17a and a light receiving lens 17b integrally molded with resin, and is provided with light shielding members 17d at predetermined locations.
This light shielding member 17d is also integrally molded with resin into the cover 17. At this time, projections 17f are provided at both ends of the light shielding member 17d, and are adapted to fit into a notch (not shown) provided in the printed circuit board 16 for positioning.

Furthermore, press members 17c for holding the printed circuit board 16 are provided at the four corners of the cover 17. This pressing member 17c also has a cover 17c.
It is integrally molded with resin.

The cover 17 is made of transparent resin, but the light shielding member 17d and the upper surface of the cover 17, except for the lenses 17a and 17b, are made opaque by being textured or the like.

Then, on the printed circuit board 16, the light emitting element 11,
After incorporating the light receiving element 12, electronic circuit 13, etc.,
This printed circuit board 16 is housed in the case 15. After the cable 14 is pulled out from a hole provided on the side of the case 15, a gasket 18 is inserted into the upper flange 17e of the cover 17, and the opening 15a of the case 15 is closed with the cover 17. At this time, the light shielding member 17d of the cover 17 positions the printed circuit board 16, and at the same time, the holding members 17c at the four corners position the printed circuit board 16 in the vertical direction.

[Brief explanation of drawings]

FIG. 1 is a sectional side view of an embodiment of this invention, FIG. 2 is a perspective view of the cover 17 shown in FIG. 1, and FIG. 3 is a sectional side view of a conventional example. 11: light emitting element, 12: light receiving element, 13: electronic circuit, 15: case, 15a: opening of case,
16: Printed circuit board, 17: Cover, 17a, 1
7b: lens, 17c: holding member, 17d: light shielding member.

Claims (1)

[Claims for Utility Model Registration] A light projecting element for projecting light onto an object to be detected; a light receiving element for receiving the projected light reflected by the object to be detected; and processing an output signal of the light receiving element. a printed circuit board mounted with an electronic circuit for the purpose of transmitting the light; a case for housing the light emitting element, the light receiving element, and the printed circuit board; and a light emitting lens disposed facing the light emitting element and the light receiving element, respectively. A reflective photoelectric switch comprising a cover integrally formed with a light-receiving lens and closing an opening of the case, wherein a cover integrally protrudes from the cover between the light-emitting lens and the light-receiving lens. A reflective photoelectric switch comprising a projection for positioning the printed circuit board.