JP2001099127A - Female screw structure and mounting hole structure for photoelectric switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a female screw structure and a mounting hole structure for a photoelectric switch for preventing a female screw from wrenching off by dispersion of a fastening torque without enlarging a size of a product. SOLUTION: This device relates to a female screw structure wherein a metallic parallel female screw 32 is buried in a resin main body 10. The female screw 32 is formed of a nearly ring shaped metallic pipe 30. In the metallic pipe 30, the female screw 32 is formed by a wave part 31 whose inner surface and outer surface are formed in a wave shape.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a female screw structure and a mounting structure for a photoelectric switch.

[0002]

2. Description of the Related Art A head portion 100 of a photoelectric switch shown in FIG. 7A causes a detection light L to enter and / or exit from a window 101. FIG. On both sides of the window 101, a pair of mounting holes 102 are provided. As shown in FIG. 7B, a female screw 103 is formed in the mounting hole 102. The head portion 100 has a male screw (screw) 104 in the mounting hole 102.
Is screwed in and attached to the bracket 110.

[0003] In recent years, there is a strong demand for miniaturization of the head section 100. On the other hand, in order to exhibit sufficient performance such as detection accuracy, it is necessary to increase the amount of the detection light L by forming the window 101 to be large. Therefore, space such as the mounting hole 102 is saved.

[0004]

The female screw 103 is formed in a resin case 105 of the head portion 100. In order to reduce the size of the head portion 100,
Since the diameter of the screw is small, the female screw 103 is easily cut off.
On the other hand, since the mounting of the head portion 100 is generally performed at a customer site,
Since the tightening torque cannot be controlled, a trouble that the female screw 103 is threaded easily occurs.

Therefore, it is conceivable to form a female screw in the bracket 110 without forming a female screw in the mounting hole 102. However, this increases the burden on the customer because the customer has to perform the hole processing and the screw processing. On the other hand, it is also conceivable that the rotation stopper of the nut is integrally formed at the time of molding the case 105 and the nut is embedded in the case at the time of attachment. However, in this case, since the outer diameter of the nut is larger than that of the mounting hole 102, the head 1
00 becomes larger. Such a problem may occur in other electronic devices and precision machines other than the photoelectric switch.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a female screw structure and a mounting hole structure for a photoelectric switch which can prevent a female screw from being cut off due to a variation in tightening torque without increasing the size of a product. It is.

[0007]

In order to achieve the above object, the present invention provides a female screw structure in which a parallel female screw made of metal is embedded in a resin body, wherein the female screw has a substantially annular shape. It is formed by a tube. The metal tube has a corrugated portion whose inner surface and outer surface are corrugated, and the corrugated portion forms the female screw.

[0008] Such an internal thread can be formed of a thin metal tube having a thickness of about 0.5 mm or less, for example. Therefore, the outer diameter of the female screw (metal tube) of the present invention is significantly smaller than that of a nut or the like. The thickness of the metal tube is preferably 0.2 mm or less, more preferably 0.1 mm or less. Further, as the material of the metal tube, various metals such as copper and iron can be adopted in addition to stainless steel and aluminum alloy.

In the present invention, "parallel female screw" means not including a tapered screw. In general, a triangular screw is used as the “screw”.

[0010] The "metal tube" of the present invention can be specified by other expressions as follows. Since the “metal tube” of the present invention is thin, it can be described as “formed of a plate-like material”. Also, if you try to form a thin metal by cutting, the metal pipe will be damaged by the stress during processing,
The metal tube of the present invention is "formed by applying bending stress"
Can be expressed as It should be noted that whether or not the metal structure is formed by bending stress can be confirmed by visually observing the metal structure or by using a magnifying glass. Further, since the “metal pipe” of the present invention is formed by bending a thin-walled pipe, the thickness of the pipe is substantially uniform, and therefore, it can be expressed as “having a substantially uniform thickness”. Note that “substantially uniform” means that a change in the thickness includes a change in the thickness caused by elongation or shrinkage of the material that occurs during bending.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an exploded perspective view of a head section 1 of a photoelectric switch with a built-in amplifier. The head part 1
Means that light enters the resin case (resin body) 10 and / or
Alternatively, a window 11 for emitting light is provided. In addition, 12 is a cable.

On both sides of the window 11, a pair of mounting holes 2,
2 are provided. The mounting hole 2 penetrates the resin case 10 from one end surface 13 to the other end surface 14 in the thickness direction X of the resin case 10.

As shown in FIGS. 2A and 2B, the mounting hole 2 is formed in a resin case 10 in an annular metal tube 3.
0 is integrally embedded by an insert or an outsert. The metal tube 30 has corrugated portions 31 at both ends. The corrugated portion 31 has a corrugated inner surface and an outer surface, and forms a female screw 32.
The metal tube 30 is integrally formed with a detent 33 that engages with the resin case 10 in the circumferential direction of the metal tube 30 to prevent the metal tube 30 from rotating. The detent part 33 is formed, for example, by a ridge that projects locally outward.

The metal tube 30 is made of a plate-like material having a substantially uniform thickness. The corrugated portions 31, 31 and the detent portion 33 are formed by applying a bending stress to the metal tube 30 made of the plate-like material. The resin case 10 shown in FIG. 2A has a female screw-shaped corrugated portion 15 corresponding to the corrugated portion 31 of the resin case 10. This prevents the metal tube 30 from coming off in the axial direction.

In such a female screw structure, since the metal tube 30 is extremely thin, the size of the resin case 10 in FIG. 1 can be reduced. On the other hand, since the female screw 32 is formed in the metal tube 30, there is no possibility that the female screw 32 is cut off.

The detent 33 is shown in FIG.
A knurl as shown in FIGS. 3A and 3B may be formed, or a ridge may be formed over the entire length of the metal tube 30 as shown in FIGS. In addition, FIG.
As shown in (f), the rotation preventing portion 33 may be formed by cutting out a part of both ends 30a and 30b of the metal tube 30.
Further, as shown in FIG. 3 (g), two waveform portions 31, 31 are formed.
The metal pipe 30 may be prevented from rotating by providing a straight pipe section 34 between the two.

As a form in which the metal tube 30 is incorporated into the resin case 10, as shown in FIG. 4A, the metal tube 30 may be completely provided up to the two end surfaces 13 and 14 of the resin case 10. 4 (b) to 4 (d), the metal tube 30 may be provided so as to be slightly retracted from the end surfaces 13 and 14 of the resin case 10. Also, as shown in FIGS. 4C and 4D,
The male screw guide 4 may be provided on the resin case 10 or the metal tube 30.

Next, a method of forming the female screw will be briefly described. As shown in FIG. 5A, a pair of outer molds 50 and 50 and a core metal 51 are used for molding a metal tube. Spiral uneven portions 52 and 53 for forming the corrugated portion 31 are formed on the outer molds 50 and 50 and the core metal 51. Straight pipe 3
Is made of a drawn or extruded material made of metal. The corrugated portion 31 (FIG. 1) is formed by inserting the core metal 51 into the straight pipe 3 and clamping the outer dies 50, 50.

As shown in FIG. 5B, the corrugated portion 31 may be formed at a part θ in the circumferential direction of the metal tube 30. Also,
The metal tube 30 only needs to be substantially annular, and therefore, FIG.
As shown in (c), it may be C-shaped.

The present invention does not limit the method of forming the female screw. For example, as shown in FIG.
After the core metal 51 is inserted into the straight pipe 3, the rolling elements 54 may be pressed against the straight pipe 3, or may be formed by pushing and expanding the straight pipe 3 with the pressure of the liquid F as shown in FIG. Is also good.

The present invention can also be applied to a so-called amplifier-separated photoelectric switch in which a head section and an amplifier section are separated. Further, the present invention, other detectors other than the photoelectric switch,
It can also be applied to electronic equipment, precision equipment, and the like.

[0022]

As described above, according to the present invention,
Since the female screw is formed with a thin metal tube, the structure becomes compact. Therefore, the size of a resin case such as a photoelectric switch can be reduced. On the other hand, the female screw is not a resin body,
Since the female screw is formed on the metal tube, the female screw is not likely to be cut off due to excessive tightening torque.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a head portion of a photoelectric switch according to the present invention.

2A is a cross-sectional view showing a mounting hole structure, and FIG. 2B is a side view of a metal tube.

FIGS. 3A and 3B are a side view and a front view showing a modification of the rotation preventing portion. FIGS.

FIG. 4 is a cross-sectional view showing an assembled form of a metal tube.

FIG. 5A is a schematic view showing a method for forming a metal tube,
(B), (c) is a front view which shows other forms of a metal tube.

FIG. 6 is a schematic view showing another molding method.

FIG. 7 is a side view and a cross-sectional view of a head unit showing a conventional example.

[Explanation of Signs] 2: Mounting hole 30: Metal tube 31: Corrugated part 32: Female screw 33: Detent part

Claims (8)

[Claims] 1. A female screw structure in which a parallel female screw made of metal is embedded in a resin body, wherein the female screw is formed by a substantially annular metal tube, and the metal tube has an inner surface and an outer surface. A female screw structure in which the female screw is formed by a corrugated portion having a corrugated surface. 2. A female screw structure in which a parallel female screw made of metal is embedded in a resin body, wherein the female screw is formed by a substantially annular metal tube, and the metal tube is made of a plate-shaped material. Female screw structure formed. 3. A female screw structure in which a metal parallel female screw is embedded in a resin body, wherein the female screw is formed by a substantially annular metal tube, and the female screw applies a bending stress to the female screw. Female screw structure formed. 4. A female screw structure in which a parallel female screw made of metal is embedded in a resin body, wherein the female screw is formed by a substantially annular metal tube, and the metal tube has a substantially uniform thickness. Female screw structure having 5. The metal tube according to claim 1, wherein the metal tube is engaged with the resin body in a circumferential direction of the metal tube to prevent the metal tube from rotating. Female screw structure with a rotating stopper. 6. The female screw structure according to claim 1, wherein the thickness of the metal tube is set to 0.5 mm or less. 7. A mounting hole structure for a photoelectric switch employing the female screw structure according to claim 1 as a structure of a mounting hole passing through a resin case of the photoelectric switch. 8. The photoelectric conversion device according to claim 7, wherein the metal tube is provided from substantially one end surface to the other end surface in the thickness direction of the resin case, and the female screw is provided near the both end surfaces. Switch mounting hole structure.