JPS6367727B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical fiber type photoelectric switch used for detecting minute objects.

Generally, in this type of switch, for example a reflective type, an optical fiber holder that holds the optical fibers constituting the optical path of each element is constructed separately from an element holder that houses the light emitting and light receiving elements. In use, the optical fiber holder is bonded to the element holder via the engaging portions of the two.

However, in the above configuration, unless special consideration is given to the coupling means between the element holder and the optical fiber holder, the coupling relationship will deteriorate and wobbling will occur.
This will lead to the intrusion of dust and the like. Furthermore, even if the above-mentioned wobbling does not occur, optical misalignment between the optical fiber and the element is likely to occur, and it is also susceptible to external disturbances. If an attempt is made to make the above-mentioned coupling relationship strong, the above-mentioned coupling structure becomes complicated and the overall size becomes large.

This invention was made in view of the above circumstances,
By accommodating the optical fiber holder and the element holder in the same case, it is possible to maintain a good optical positional relationship between the optical fiber and the element, and there is less influence from external disturbances. The purpose is to provide a fiber type photoelectric switch.

An embodiment of the present invention will be described below with reference to the drawings.

Figures 1 and 2 show a reflective photoelectric switch. In the figures, numeral 10 is a box-shaped case made of synthetic resin, etc.
0 consists of a case body and a cover 102 that are bonded together with adhesive or the like. 11 is a shield plate bent into a U-shape, 12 and 13 are light emitting and light receiving elements, 14 is an element holder, and 15 is an operation display element 1.
This is a printed wiring board to which 16 and the like are attached.

The element holder 14 is formed of synthetic resin or the like into a box shape with an open front end, and locking protrusions 141 formed on both sides are locked into locking holes 111 formed in the flexible plate 11. By stopping it, it is firmly attached inside the case body 101 via this flexible plate 11. Inside the element holder 14, recesses 142 and 143 for element setting are formed in two stages, upper and lower, in the front-rear direction, and a pair of upper and lower protruding walls 144, 145 formed on the rear end surface are provided with the wiring board. Support groove 146, 1 which also serves as an insertion guide of 15
47 (Fig. 3) is formed. Each of the above recesses 1
42, 143 to hold each element 12, 13 by press fit through elastic cylinders 16, 17 made of rubber, etc., and lead terminals 12a, 13 of each element 12, 13.
By brazing and fixing a to the wiring board 15, the light emitting and light receiving elements 12, 13 are integrally attached to the holder 14 together with the wiring board 15, so that they can be easily incorporated into the case body 101. I can do it. In Figure 3, 14
Reference numerals 8 and 149 are formed on the holder 14 to connect each lead terminal 12 of the light emitting and light receiving elements 12 and 13.
This is a through hole that penetrates through a and 13a.

Reference numeral 18 denotes an external lead-out cord connected to the wiring board 15, and drawn out to the outside through a hole 10a formed in the rear wall of the case 10. The cord 18 and the case 10 are made liquid-tight by a packing 19 made of rubber or the like and having a convex cross section. Annular edge portions 20 and 21 are formed in the case 10 to correspond to the large diameter and small diameter portions 191 and 192 of the rubber packing 19, and the packing 19 of these edge portions 20 and 21
The above-mentioned liquid-tight effect is improved by biting into the hole.

22 and 23 are optical fibers, and the optical fiber 2
2 constitutes an optical path for transmitting the light from the light emitting element 12 to the object to be detected, and an optical fiber 23 constitutes an optical path for transmitting the reflected light from the object to be detected to the light receiving element 13. 24 is a holding base for both the optical fibers 22 and 23, and 25 is a stopper.
The element holder 14 is attached to the rear end surface of the holding base 24.
As shown in FIGS. 4 to 6, a convex portion 240 that fits inside is formed on the square-shaped wall 140 surrounding the element setting recesses 142 and 143, and a columnar protrusion 24 on the front end surface is formed.
1 has a fiber insertion hole 242 formed therein. A recess 243 for resin filling, which communicates with the insertion hole 242, is formed in the convex portion 240 of the time keeping base 24. 247 is a positioning protrusion formed on the convex portion 240; 150 is the element holder 1;
4 and is a notch portion that fits into the protrusion 247.

On the upper and lower surfaces of the plug body 25, there are grooves 244 formed on the upper and lower inner walls of the resin filling recess 243,
Grooves 251 and 252 are formed corresponding to the grooves 245, respectively. One end portion 22a, 2 of each optical fiber 22, 23 is inserted into each of these grooves 251, 252, respectively.
3a, one end surface of each of the optical fibers 22 and 23 is connected to the light emitting and light receiving element 1.
2 and 13 can be easily opposed. One end portion 22a, 23 of each of the optical fibers 22, 23
When a is inserted into the grooves 251 and 252, for example, if the fiber is bent with a large curvature, such as the optical fiber 23, it corresponds as shown in FIGS. 1, 2, and 4. By forming a conical taper portion 253 at a portion spanning the corner of the groove 252, damage to the optical fiber 23 due to bending can be prevented. Horizontal grooves 254 and 255 are formed on both side surfaces of the plug body 25. One end portion 22a, 23 of each of the optical fibers 22, 23
a into the upper and lower grooves 251, 252 of the plug 25, and insert the plug 25 into the resin filling recess 24.
3, and then inject epoxy resin 26 from either one 254 of the lateral grooves 254, 255 to fill the recess 243. As the resin 26 solidifies, one end 22 of the optical fibers 22, 23
a, 23a are integrated into the holding base 24 together with the plug body 25 and the resin 26. The holding base 24, the stopper 25 and the resin 26 constitute a holding body 27 for the optical fibers 22 and 23. In this case, the other lateral groove 255 serves as an escape port for air when the resin 26 is injected, so that the flow and solidification of the resin 26 are improved.

The other end 22b of both the optical fibers 22, 23,
23b is led out forward from the hole 104 of the conical cylinder part 103 on the front wall of the case 10, and these lead-out parts 22b and 23b are inserted into a bendable metal pipe 28 made of stainless steel, copper, etc. (See Figures 7 to 9). By using this metal pipe 28, the other ends 22b, 23b of the optical fibers 22, 23 can be directed toward the object to be detected simply by bending the metal pipe 28, without having to hold the other ends 22b, 23b of the optical fibers 22, 23 with special holding means. This metal pipe 2
8 is the other end 22 of each of the optical fibers 22 and 23;
b, 23b, and has an inner diameter such that a gap (play) 29 exists between the bending strength and the bending strength. In this embodiment, a small-diameter auxiliary pipe 30 is used to hold the gap 29, and this gap holding means is
Spacers such as resin may be used instead of zero.

One end portion 28a of the metal pipe 28 is formed into a flattened shape that widens at the end as shown in FIGS. is attached to.

Reference numeral 31 denotes a relatively hard frusto-conical rubber packing inserted into the metal pipe 28 and interposed in the conical cylinder part 103 of the case 10, and the rear end face thereof is opposed to the partition wall 105 of the case 10. An O-ring portion 310 having a semicircular cross section is integrally formed. An annular protrusion 10 is provided on the inner wall of the conical cylinder portion 103 corresponding to the conical surface of the rubber packing 31.
6 is formed. When the case body 101 and the cover 102 are connected, the rubber packing 3
The annular protrusion 106 bites into the conical surface of the O-ring part 31 due to the elastic deformation of the rubber packing 31.
comes into pressure contact with the partition wall 105, thereby achieving sealing in this area.

In the above configuration, prior to the detection operation of the object to be detected, the metal pipe 28 is bent appropriately and set so that the other end surfaces of the optical fibers 22 and 23 are accurately oriented toward the object to be detected. In this state, when the light emitting and light receiving elements 12 and 13 are driven, the light from the light emitting element 12 passes through the optical fiber 22 and is irradiated onto the object to be detected. The reflected light from the object to be detected passes through the optical fiber 23 to the light receiving element 1.
The presence or absence of the object to be detected can be detected depending on whether or not light is received by the object.

Here, one end portion 22a, 23a of the optical fibers 22, 23 is accurately positioned on the light emitting and light receiving elements 12, 13 by the holding base 24 and the stopper 25, and then the concave portion of the holding base 24 is placed. Resin 2 to 243
6, the holding base 24 and the stopper 2
5 and resin 26 to form the optical fiber 22,
In particular, since the optical fiber holder 27 and the element holder 14 made up of these three members 24 to 26 are fitted in the same case 10, each optical fiber 22 can be held in position. , 23 and each element 12, 13 is maintained well, there is no fear of intrusion of dust, etc., and it becomes easier to respond to miniaturization.

Note that in the above embodiment, the light emitting and light receiving element 1
Although the description has been made using a reflective photoelectric switch using elements 2 and 13 as an example, the present invention can be applied to any photoelectric switch having at least one of the elements.

As described above, according to the present invention, there is provided a holding base having a recess for resin filling and an optical fiber insertion hole for introducing an optical fiber into the recess, and a holding base having one end of the optical fiber facing the element. a plug body having a first groove leading to the resin and a second groove for injecting the resin and fitted into the opening of the holding base; and a plug body filled into the recess from the second groove and held. With a structure consisting of a resin that fixes the base and the plug, and a case that fits the optical fiber holder made of the holding base, the plug, and the resin together with the holder containing the element, the optical fiber and the element can be connected. It is possible to provide a highly reliable optical fiber type photoelectric switch in which the optical coupling relationship is maintained well.

[Brief explanation of drawings]

1 and 2 are a cross-sectional view and an exploded perspective view showing an example of an optical fiber photoelectric switch according to the present invention, FIG. 3 is a perspective view showing an element holder and a wiring board, and FIG. 4 is an optical fiber holder. Figure 5 is a cross-sectional view of the optical fiber holder holding the optical fiber, Figure 6 is a rear view of the holder, and Figure 7 is a partially broken side view showing an example of a metal pipe. 8 is a rear view of the same metal pipe, and FIG. 9 is an enlarged sectional view of a packing portion corresponding to the metal pipe. 10... Case, 12... Light emitting element, 13...
Light receiving element, 14...Element holder, 22, 23...
Optical fibers, 22a, 23a...one end, 24...
...Optical fiber holding base, 25... Plug body, 26...
Resin, 27... Optical fiber holder, 243... Recess for resin filling, 251, 252... Groove for guiding optical fiber, 253... Conical taper portion, 254...
Groove for resin injection, 255... Groove for exhaust.

Claims (1)

[Scope of Claims] 1. A fiber-optic photoelectric switch having at least one of a light-emitting element and a light-receiving element, and in which an optical path corresponding to the element is formed of an optical fiber, which includes a recess for filling with resin and a recess for filling with resin. a holding base having an optical fiber insertion hole for introducing the optical fiber into the recess; a first groove for guiding one end of the optical fiber to face the element; and a second groove for injecting resin. a plug that is fitted into the opening of the holding base; a resin that is filled into the recess through the second groove and fixes the holding base and the plug; 1. An optical fiber type photoelectric switch comprising: a case into which an optical fiber holder made of a body and a resin is fitted together with a holder holding the element. 2 In the groove for guiding the optical fiber in the plug body,
2. The optical fiber type photoelectric switch according to claim 1, wherein a conical taper for preventing optical fiber breakage is formed at a corner where the groove straddles.