JPH0534102A - Positon detecting sensor - Google Patents

Abstract

PURPOSE:To make it possible to prevent the intrusion of water and oil into the case of a main body for a long period by forming the case of the main body in a cylindrical shape having the bottom, and making an opening part small so that the part is tightly sealed with a cap body readily and securely. CONSTITUTION:An O ring 83 is mounted on a bush 15, and the bush 15 is coupled into a hole 31 of a cap body 12. An O ring 84 is mounted. A lead wire 14 is made to pass, and a tightening band 46 is tightened. An O ring 81 is mounted on the cap body 12. The tip part of the lead wire 14 is soldered to a substrate 13. The substrate 13 is mounted on a substrate supporting frame 44. The frame 44 is inserted into a main body case 11. At the same time, the cap body 12 is coupled into an opening part 21 of the case 11. A potting agent is injected through a window hole 25 and filled into the case 11. A display window 16 and an O lead 82 are mounted before the hardening of the potting agent. A shield cover 17 applied thereon. The case 11 has the cylindrical shape, and the opening part 21 is small. The length of the tightly sealed part between the opening part and the cap body 12 is short. The sealed part can be formed in the smooth curved state. The sealing with the 81 becomes easy and secure. The inside of the case 11 is tightly sealed with the O rings 82-84.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a position detecting sensor for detecting the stroke position of a piston in a fluid pressure cylinder.

[0002]

2. Description of the Related Art Conventionally, a fluid pressure cylinder such as a hydraulic cylinder or a pneumatic cylinder is equipped with a position detecting sensor for detecting the stroke position of its piston.

Such a position detecting sensor is mounted, for example, on the outer peripheral surface of a cylinder tube and is operated by the magnetic field of a permanent magnet attached to a piston sliding in the cylinder tube.

Conventionally, a position detecting sensor is a printed circuit board in which a magnetic sensor such as a reed switch or a magnetoresistive element is mounted in a case body made of synthetic resin or the like and having a relatively wide upper surface opened. It was arranged and the opening was covered with a lid.

In order to maintain the waterproof property of the printed circuit board, the opening and the lid are sealed with an adhesive or the periphery of the printed circuit board is filled with resin.

[0006]

However, although the conventional general position detecting sensor has a provisional waterproof property, the opening of the main body case is relatively wide and has a rectangular shape. It was difficult to sufficiently seal the inside from the outside and maintain good waterproofness for a long period of time.

Therefore, when used in a bad environment where water or oil splashes constantly fly, water or oil permeates into the printed circuit board of the position detection sensor during long-term use, and There was a risk that the electrodes of the above would short circuit or cause insulation failure.

In view of the above problems, it is an object of the present invention to provide a position detecting sensor capable of preventing water or oil from entering the body case for a long period of time.

[0009]

In order to solve the above problems, a position detecting sensor according to the invention of claim 1 detects the position of a moving object by a magnetic field of a permanent magnet provided on the moving object. Sensor for position detection of
A bottomed cylindrical main body case, a lid that hermetically closes the opening of the main body case, a substrate mounted in the main body case, a magnetic sensor attached to the substrate, and an operation of the magnetic sensor. An indicator light attached to the substrate for displaying a state, a lead wire connected to the magnetic sensor and the indicator light and pulled out from the lid body, and the lead wire attached to the lid body. And a display window for sealing the outer periphery of the main body case in a sealed state and for confirming the display state of the indicator lamp from the outside.

In the position detecting sensor according to a second aspect of the invention, an annular packing for sealing is attached to the lid, the sealing member, and the display window.

[0011]

Since the main body case has a bottomed cylindrical shape, the opening is relatively small, and the sealing by the lid is easily and surely performed. For example, when sealing is performed with an annular packing such as an O-ring, the sealing is reliable and inexpensive.

The magnetic sensor is operated by a magnetic field of a permanent magnet provided on an external moving object, and a signal is output by a lead wire. Further, the indicator light is turned on or off according to the operating state of the magnetic sensor, and the display state is confirmed from the outside through the display window.

[0013]

1 is a sectional front view of a position detecting sensor 1 according to the present invention, FIG. 2 is a sectional side view taken along line II-II in FIG.
FIG. 3 is a plan view of the position detection sensor 1 of FIG.

The position detecting sensor 1 is a body case 1
1, lid 12, substrate 13, lead wire 14, bush 15,
The display window 16 and the shield cover 17 are included. The main body case 11 is made of a synthetic resin and has a bottomed tubular shape whose internal cross section is substantially oval.

In the opening 21 of the main body case 11, the lid 1
The stepped portion 22 for mounting the O-ring 81 that seals between the main body case 11 and the outer casing 2 is provided over the entire circumference of the inner peripheral surface of the opening 21. Engaging recesses 23 are provided at two locations.

The inner peripheral surface of the main body case 11 serves as a guide for facilitating the insertion of the board 13, and is fixed to the peripheral wall portion 27 of the main body case 11 so as not to move the inserted board 13. Two substrate supporting ridges 2 for
4 are provided in parallel with each other.

A window hole 25 for mounting the display window 16 and a step for mounting an O-ring 82 for sealing between the main body case 11 and the display window 16 are provided at a position near the bottom portion 11a of the main body case 11. A section 26 is provided.

The lid 12 has an opening 21 in the body case 11.
And is made of a synthetic resin of the same material as the main body case 11. The lid 12 has a hole 3 for inserting the bush 15 with a slight interference fit.
1, a step portion 32 for mounting the O-ring 81, and a claw portion 33 that engages with each of the engaging concave portions 23 provided in the main body case 11 and performs a retaining action.

On the substrate 13, a reed switch 41 and a light emitting diode 4 connected in series with the reed switch 41.
2. A diode 43 connected in parallel with the light emitting diode 42 and having a reverse polarity is attached.

The substrate 13 is supported by the substrate support frame 44. The substrate support frame 44 is made of a synthetic resin having elasticity, and has a frame shape surrounding the periphery of the substrate 13. The substrate support frame 44 supports the substrate 13 by pressing it with pressing claws 45 provided on the substrate support frame 44.

The board supporting frame 44 is elastically sandwiched between the board supporting ridge 24 and the peripheral wall portion 27 of the main body case 11 so that the board supporting frame 44 is formed.
And the substrate 13 is fixed.

The substrate 13 also has a reed switch 41.
The lead wire 14 is connected by soldering at one end of the lid 1 and one end of the light emitting diode 42.
It is pulled out to the outside through the bush 15 attached to 2. A tie band 46 is wound around the lead wire 14 on the inner surface side of the bush 15 so as to prevent the bush 15 from coming off.

The bush 15 is made of metal and is inserted and fixed in the hole 31 of the lid 12. In bush 15,
A peripheral groove 51 into which a convex portion provided on the inner peripheral surface of the hole 31 of the lid body 12 is fitted to prevent the lid body 12 from coming off, the lid body 1
A peripheral groove 52 for mounting an O-ring 83 for sealing between the bush 2 and the bush 15, a hole 53 for passing the lead wire 14,
A step portion 54 for mounting an O-ring 84 that seals the outer circumference of the lead wire 14 is provided, respectively.

Further, on the bush 15, a jam nut 55 made of metal and an inner terminal cap 5 made of synthetic resin for attaching the tube 18 for the outer cover shown by the chain line.
6, outer terminal cap 57, seal packing 58,
A ring washer 59 is provided.

The display window 16 is made of transparent synthetic resin,
It has a columnar shape with a collar. The bottom surface of the display window 16 is a concave spherical surface, and the light emitted from the light emitting diode 42 is focused on the top surface of the display window 16.

The shield cover 17 is made of a metal plate,
It covers about half the circumference of the peripheral wall portion 27. The shield cover 17 is provided with a mounting bracket portion 61 and a hole 62.

Next, the order of assembling the position detecting sensor 1 will be briefly described. With the O-ring 83 attached to the bush 15, this is inserted into the hole 31 of the lid 12 and coupled. An O-ring 84 is attached to this, the lead wire 14 is passed through, and the binding band 46 is tightened.

Then, the tip portion of the lead wire 14 is soldered to the substrate 13 with the O-ring 81 first attached to the lid 12. The substrate 13 is mounted on the substrate support frame 44, the substrate support frame 44 is inserted into the main body case 11, and the lid 12 is fitted into the opening 21 of the main body case 11.

A potting agent is injected through the window hole 25 to fill the inside of the main body case 11. The display window 16 and the O-ring 82 are attached and the shield cover 17 is covered before the potting agent is cured.

According to the above-mentioned embodiment, since the main body case 11 is cylindrical and the opening 21 is relatively small, the lid 1
Since the length of the portion to be sealed between the two and the two can be made into a smooth curved shape, the sealing by the O-ring 81 is easy and reliable.

Further, the O-rings 82, 83 and 84 are surely sealed between the main body case 11 and the display window 16, between the lid 12 and the bush 15, and between the bush 15 and the lead wire 14, respectively. The inside of the main body case 11 can be sufficiently sealed from the outside, and good waterproofness can be maintained for a long period of time.

Therefore, even when used in a bad environment such as water or oil, it is possible to prevent them from entering the main body case 11 and maintain a good insulation state of the substrate 13. Further, since the O-rings 81 to 84 are inexpensive, the position detecting sensor 1 can be provided at low cost.

According to the above-described embodiment, the respective parts can be combined and integrated without using an adhesive, so that the assembly is easy. In the above-described embodiment, the potting agent is injected into the main body case 11. According to this, the waterproofness of the substrate 13 becomes more perfect and it becomes stronger against vibration and the like, but the injection of the potting agent is omitted. It is also possible to disassemble and reassemble in that case.

In the above-mentioned embodiment, the structure, shape, size, material, electric circuit of the substrate 13 and the like of each part of the position detecting sensor 1 can be variously changed other than those described above. Further, the position detecting sensor of the present invention can be used for detecting various moving objects other than the piston of the fluid pressure cylinder.

[0035]

According to the present invention, it is possible to prevent water or oil from entering the body case for a long period of time.

According to the second aspect of the invention, it is possible to provide a position detecting sensor at low cost.

[Brief description of drawings]

FIG. 1 is a cross-sectional front view of a position detecting sensor according to the present invention.

FIG. 2 is a sectional side view taken along the line II-II in FIG.

FIG. 3 is a plan view of the position detection sensor of FIG.

[Explanation of symbols]

1 Position detection sensor 11 body case 12 Lid 13 board 14 lead wire 15 bush (sealing member) 16 Display window 41 Reed switch (magnetic sensor) 42 Light emitting diode (indicator) 81, 82, 83 O-ring (packing)

Claims (2)

[Claims] 1. A position detecting sensor for detecting the position of a moving object by a magnetic field of a permanent magnet provided on the moving object, comprising: a cylindrical main body case having a bottom and an opening portion of the main body case. A lid closed in a sealed state, a substrate mounted in the main body case, a magnetic sensor attached to the substrate, an indicator light attached to the substrate for displaying an operating state of the magnetic sensor, A lead wire that is connected to the magnetic sensor and the indicator light and is pulled out from the lid body; a sealing member that is attached to the lid body and seals the outer circumference of the lead wire; A sensor for position detection, which is attached in a state, and has a display window for confirming the display state of the indicator lamp from the outside. 2. The position detecting sensor according to claim 1, wherein an annular packing for sealing is attached to the lid body, the sealing member, and the display window.