JPS60243923A - Sensor for proximity switch - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] <Technical Field of the Invention> The present invention provides a high-frequency oscillation type proximity switch sensor that detects the separation or approach of an object in a non-contact state using frequency changes of a coil L and a capacitor C. It is related to.

<Prior Art and Problems> A high-frequency oscillation type proximity switch has an oscillation circuit including a detection coil, and the circuit is configured such that the detection coil serves as one element that determines the oscillation frequency.

When an object such as metal approaches the detection coil, the inductance of the coil changes, causing the oscillation frequency to change or stop oscillation, and the approach of the object is detected based on the oscillation state of this oscillation circuit. Therefore, the detection coil is often installed at the detection end of the proximity switch, that is, usually the front end, and cables forming power lines, signal lines, etc. are drawn out from the other end, that is, the rear end.

This type of proximity switch has advantages such as having no mechanical operating parts and being resistant to dust, etc., unlike those that project light, so it is often used in harsh environments, such as when Robots are used as machine tools and automatic assembly machines, and in particular, they are incorporated into the fingertips of such robots and used to check whether there are metal objects in the fingertips, and in recent years, the scope of their use has been expanding. .

As the scope of use of proximity switches expands in this way, proximity switches ranging from relatively large ones to miniaturized ones are required depending on the equipment to be used. or,
Depending on the request, the sensor can be connected to a sensor-type proximity switch that integrates a sensor section with a detection coil and a circuit section that determines whether an object is moving away or approaching based on information obtained from the sensor section. There is a sensor-separated type proximity switch in which the sensor section and the circuit section are separated. The former sensor-type proximity switch is unitized and can be easily integrated into equipment, but it has the problem of being bulky, and the latter sensor-separated proximity switch The sensor part and the detection circuit part are separated, and it is necessary to connect them with a coaxial cable, etc., so it is somewhat inconvenient to install it, but since only the sensor part can be placed in the detection part of the equipment, the size of the detection part on the equipment side is It has the advantage of being able to reduce the size.

In addition, today's robots are handling smaller parts year by year, and sensor-separated proximity switches that can be miniaturized have become popular.

As shown in FIG. 3, this type of sensor-separated proximity switch includes a sensor section 1 including a resonant circuit of a coil L and a capacitor C, an oscillation circuit 4, an amplifier 5, a rectifier circuit 6, and a discrimination circuit 7. 2, and a cable 3 that connects the sensor section 1 and the circuit section 2. And sensor part 1
When a metal object arrives at the coil L, the inductance of the coil L changes, and this change in inductance changes the oscillation state of the oscillation circuit 4. The output of the oscillation circuit 4 is amplified by the amplifier 5, and then the rectifier circuit 6 The discrimination circuit 7 compares the reference voltage with the voltage applied from the oscillation circuit 4, and the applied voltage from the oscillation circuit 4 is more than the reference voltage. Depending on whether the object is large or small, the presence or absence of detection of a metal object is output.

The structure of the sensor unit 1 includes a metal main body case with both ends open, a detection coil wound in a ring shape, a coil spool around which the detection coil is completely wound, and a lead wire of the detection coil. Consists of connected cables, etc.
More specifically, as shown in FIG. 4, the detection coil L is wound around a coil bobbin 19 made of insulating synthetic resin, etc., and this is inserted into the groove 8A of the pot-shaped ferrite core 13 with an E-shaped cross section. Built-in. The ferrite core 13 is formed by storing the coil bobbin 19 wound with the sensing coil L in the groove 8A, and the lead wires 13 and 14 of the sensing coil L wound around the coil bobbin 19 extend to the rear side of the coil bobbin 19. The front side of the coil bobbin 19 is housed in a bottomed cylindrical synthetic resin case 31, and the synthetic resin case 31 is housed and fixed in the opening at the tip of the cylindrical metal main body case 9. .

However, in the sensor section 1 in which the E-shaped pot-shaped ferrite core 8 is used in the sensor section 1 and the coil bobbin 19 is housed in the core 8, the ferrite core 8 is generally not affected by external force. However, since the E-shaped pot-shaped ferrite core has the property of being weak and easy to wind, there is a limit to miniaturization, and the coil cannot be wound directly, so once the coil bobbin 19 is After winding, the coil bobbin 19 and the coil bobbin 19 are housed in the groove 8A of the ferrite core 8, which has the problem of not only increasing the size but also increasing the cost.

<Object of the Invention> The present invention has been made in view of the problems of the conventional proximity switch, and an object of the present invention is to provide a sensor for a proximity switch that can be miniaturized and is inexpensive.

<Configuration and Effects of the Invention> In order to achieve the above object, a proximity switch sensor according to the present invention is a proximity switch sensor in which a spool around which a detection coil is wound is inserted into a cylindrical body case. The spool is formed of a resin spool half and a ferrite core spool half each having a substantially T-shaped cross section, and the other spool is connected to a low mating hole provided in the central protrusion of one spool half. By forming half-shaped central protrusions that fit together and winding the detection coil on the spool, it is possible to reduce the size of the spool, and also to obtain an inexpensive proximity switch. .

<Embodiment of the Invention> Hereinafter, an embodiment of a sensor for a proximity switch according to the present invention will be described in detail with reference to FIGS. 1 and 2.

The circuit configuration of the proximity switch in this embodiment is equivalent to the circuit configuration shown in FIG. 3, and there is no change in the circuit configuration itself, so the portion corresponding to the sensor section 1 in FIG. Only examples are given.

Therefore, to explain the sensor part, FIG. 1 is an axial cross-sectional view of a sensor part 100 for a proximity switch according to the present invention, and FIG. 2 is an exploded perspective view thereof. 3 is a cable in which core wires 3A, 3A are each coated with an insulating material 3B, and further coated with an insulating material 3C. Reference numeral 109 denotes a cylindrical main body case with openings at both ends, and the main body case 109 has a larger diameter at the inner circumference near the front end opening than at the center inner circumference. Reference numeral 108 denotes a coil spool around which a predetermined number of detection coils L are wound, and the coil spool 108 consists of a synthetic resin spool half-hole 108B and a ferrite core spool half-hole 108A, each of which has a substantially T-shaped axial cross section. The spool half-open 108B is provided with a protruding portion at the center of one side, and this protruding portion is provided with a fitting hole 108D that is bored along the axial direction from the distal end surface. Further, the spool half body 10
8A is provided with a protruding part 108E at the center of one side, and this protruding part 108Ek is press-fitted into the fitting hole 108D of the spool half body 108B, and the spool halves 108A and 108
B and B are assembled together. 117 A cable holder that is fixed to the other side of the spool half-rest 108A of the U coil spool 108, for example, with an adhesive, and a pair of protrusions 117A are provided on the back surface of the cable holder 117, and the protrusions 117AK are Fitting holes 117a are each provided along the axial direction. Further, the outer peripheral part of the spool half-opened 108A and the cable holder 1
Cutouts 108C and 117B for guiding the lead Hii3°114 wound around the coil winding portion 108F of the coil spool 108 to the rear are provided on the outer periphery of the coil spool 108 at positions displaced by 1800 degrees, respectively. It is provided. 1
Reference numeral 20 indicates a cylindrical core formed of a ferrite material that is fitted into the large-diameter inner peripheral portion of the front end of the main body case 109, and 115 is an insulating resin material filled and solidified within the main body case 109.

Proximity switch sensor section 10 composed of these members
00 assembly begins with the spool half 108A.

108B and the cable holder 117 are integrated, the detection coil L'ff: is wound a predetermined number of times around the winding portion 108F of the coil spool 108, and the wound detection coil L
The lead wires 113 and 11.4 are connected to the notches 108C and 11
Each core wire 3A of the cable 3 is arranged to extend rearward from 7B, and further extends through the main body case 109.
, 3A are fitted and positioned in the entire fitting hole 117a. After winding the lead wires 113° to 114 degrees around the core wire 3A of the cable 3 with the core wire 3A fixed to the coil spool 108 in this way, each core wire 3A, 3A and each lead wire 113, 114 are wound.
and are fixed by soldering. Next, with the coil spool 108 and the cable holder 117 fitted into the cylindrical core 120, the cylindrical core 120 is assembled into the large diameter portion of the inner periphery at the front end of the main body case 109, and then the inside of the main body case 109 is twisted. The insulating resin material 115 is filled and solidified to complete the process.

Sensor part 10 of the proximity switch assembled in this way
0 is shared with the control circuit shown in FIG. 3, and when the detection coil L is energized, the detection coil L is excited, and the magnetic flux of this detection coil L flows through the cylindrical core 120 and the spool half-open 108A. It is configured to flow, and when a metal object approaches the tip of the sensor section 100, the inductance of the detection coil L changes, and the control circuit detects this change in inductance to detect the approach of the object.

That is, in the present invention, since the detection coil Lk can be directly wound around the coil winding portion 108F of the coil spool 108, it is possible to downsize the sensor coil and reduce costs.

Although this embodiment shows the case of a parallel cable 3 in which the core wires 3A and 3Ai are arranged in parallel, it is of course possible to use a coaxial cable, and it can also be applied to a sensor-type proximity switch. You may do so.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a sensor in a proximity switch according to the present invention, and FIG. 2 is an exploded perspective view of the sensor shown in FIG.
Fig. 3 is a circuit diagram showing the general circuit configuration of a proximity switch, and Fig. 4 is a -1 of the sensor section in a conventional proximity switch.
FIG. L: Detection coil, 100: Sensor, 108: Coil bouquet, 108A, 108B: Spool half-closed, 109: Main body case, 108D: Fitting hole,
108E...Central protrusion. Patent applicant: Tateishi Electric Co., Ltd. 7 company agent: Patent attorney: Tetsuji Iwakura (1 other person)

Claims (1)

[Claims] A proximity switch sensor comprising a spool wound with a detection coil inserted into a cylindrical body case, the spools each comprising a resin spool half and a ferrite core spool half each having a substantially T-shaped cross section. 1. A sensor for a proximity switch, characterized in that the central protruding part of the other spool half is fitted into the fitting hole provided in the central protruding part of one spool half.