JPS6245130Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to an optical fiber photoelectric switch used for detecting minute objects, etc., and more specifically, a bendable metal pipe is fitted onto the external end of the optical fiber. In particular, the present invention relates to an optical fiber type photoelectric switch that improves the sealing performance between the metal pipe and the case.

An embodiment of this 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 100 and a cover 101, which are divided into two along the axis and bonded to each other with an adhesive or the like. Reference numeral 11 denotes 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 a printed wiring board to which an operation display element 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 100 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 tubes 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 and 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 on the case 10 in correspondence with the large diameter and small diameter portions 191 and 192 of the rubber packing 19,
By biting these edge portions 20 and 21 into the packing 19, the liquid-tight effect is improved.

22 and 23 are optical fibers, and the optical fiber 2
Reference numeral 2 constitutes an optical path for transmitting the light from the light emitting element 12 to the object to be detected, and 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 setting recess 14 of the element holder 14 is provided on the rear end surface of the holding base 24 as shown in FIGS. 4 to 6.
A convex portion 240 that fits inside the square-shaped wall 146 surrounding the cylindrical portion 2,143 is formed, and a columnar protrusion 240 on the front end surface is formed.
41 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 holding base 24. 247 is a positioning protrusion formed on the protrusion 240, and 150 is a notch formed on the holder 14 to fit with the protrusion 240.

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 the fiber a is inserted into the grooves 251 and 252, for example, if the optical fiber 23 is bent with a large curvature, the corner portion will be removed as shown in FIGS. 1, 2, and 4. By forming a conical tapered portion 253 in a portion of the groove 252 corresponding to the groove 252, damage to the optical fiber 23 due to bending can be prevented. Horizontal grooves 2 are provided on both sides of the plug body 25.
54,255 are formed. One end portion 22a, 23a of each of the optical fibers 22, 23 is connected to the stopper 2.
After the plug body 25 is press-fitted into the resin filling recess 243 while fitting into the upper and lower grooves 251 and 252 of the 5, the epoxy resin 26 is injected from either one 254 of the horizontal grooves 254 and 255. When the recess 243 is filled, the resin 26 solidifies and the one ends 22a, 23 of the optical fibers 22, 23 are formed.
a is integrated with the holding base 24 together with the stopper 25 and resin 26. The optical fibers 22, 2 are connected by the holder 24, the stopper 25 and the resin 26.
3 holder 27 is constituted. 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). This metal pipe 28 is connected to the other ends 22b, 23 of the optical fibers 22, 23.
It has an inner diameter such that a gap (play) 29 exists between it and b. In this embodiment, in order to maintain the air gap 29, a small diameter auxiliary pipe 3 is used.
0 is used, but this gap holding means may be a spacer such as resin instead of the auxiliary pipe 30.

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 designates a relatively hard frusto-conical rubber packing inserted into the metal pipe 28 and interposed within the conical cylinder portion 103 of the case 10, and has a protrusion facing the partition wall 105 of the case 10 on its rear end surface. A strip ring part, for example, an O-ring part 31 with a semicircular cross section
0 is integrally formed. For example, a triangular annular protrusion 106 is formed on the inner wall of the conical cylinder portion 103 corresponding to the conical surface of the rubber packing 31.

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, even if the optical fibers 22 and 23 are flexible, since the other ends 22b and 23b are covered with the metal pipe 28, the metal pipe 28 can be simply bent without preparing a holding means. Thus, the other end surfaces of the optical fibers 22 and 23 can be accurately directed toward the object to be detected. moreover,
Since the metal pipe 28 has a gap 29 between it and the optical fibers 22 and 23, even if it is frequently bent when facing an object to be detected, play in the gap 29 will cause the metal pipe to 28 can be effectively prevented from breaking.

By the way, in this switch, it is necessary to improve the sealing performance in consideration of various usage modes. In particular, in the configuration using the metal pipe 28, it is required to ensure the sealing performance between the metal pipe 28 and the case 10. However, in the above configuration, by using the packing 31, the above requirement can be met. In other words, the above packing 3
Since 1 has a truncated conical shape and is relatively hard,
When the case body 101 and the cover 102 are connected, the annular protrusion 106 formed on the inner wall of the conical cylindrical portion 103 of the case 10 bites into the conical surface of the packing 31, first sealing this part. make it happen. Further, due to the biting of the annular projection 106, the entire rear half of the backing 31 is elastically deformed rearward, and the semicircular ring portion 310 that was in contact with the partition wall 105 on the case 10 side is moved from the partition wall 105 to the partition wall 105.
05, the contact pressure per unit area of this portion is increased and high sealing performance is exhibited. Of course, the cross-sectional shapes of the ring portion 310 and the annular projection 106 can be changed as appropriate.

Note that in the above embodiment, the light emitting and light receiving element 1
Although the description has been given 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 this invention, the directing operation of the lead-out end face of the optical fiber toward the object to be detected can be easily and accurately performed by using the metal pipe. The truncated cone-shaped packing provided between the two provides effective sealing between the two, making it possible to provide an easy-to-use optical fiber type photoelectric switch.

[Brief explanation of the drawing]

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, 22, 23... Optical fiber, 22a,
23a...One end of the optical fibers 22, 23, 27
...Fiber holder, 28...Metal pipe, 28
a... One end of the metal pipe 28, 31... Packing, 101... Case body, 102... Cover, 106... Annular projection, 310... Projection ring portion.

Claims (1)

[Scope of utility model registration request] A case that is divided into two parts along the axis and houses at least one of a light emitting and a light receiving element, and a case that holds one end of an optical fiber with the other end led out to the outside, and an optical fiber holder whose one end surface is positioned to face the element; a bendable metal pipe fitted over the lead-out end of the optical fiber; a relatively hard truncated cone-shaped packing for sealing between the packing and the case; a protruding ring portion abutting against the partition wall on the case side is formed around the axis of the rear end surface of the packing; An optical fiber type photoelectric switch in which an annular protrusion that bites into the conical surface of the packing is formed on the inner wall of the case.