JP3012371B2 - Position detection sensor - Google Patents

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 a stroke position of a piston in a hydraulic cylinder.

[0002]

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

[0003] Such a position detecting sensor is mounted, for example, on the outer peripheral surface of a cylinder tube, and is operated by a magnetic field of a permanent magnet attached to a piston sliding in the cylinder tube.

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

[0005] In order to maintain a certain level of waterproofness of the printed circuit board, the space between the opening and the lid is sealed with an adhesive, or a resin is filled around the printed circuit board.

[0006]

However, although the conventional general position detecting sensor has a certain degree of waterproofness, the opening of the main body case is relatively wide and rectangular, so that the conventional position detecting sensor has a relatively large opening. It has been difficult to sufficiently seal the inside from the outside and maintain good waterproofness for a long time.

Therefore, when the device is used in a bad environment where water or oil or the like is constantly flying, water or oil permeates into the printed circuit board of the position detecting sensor during long-term use, and There is a possibility that the electrodes may be short-circuited or insulation failure may occur.

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

[0009]

According to a first aspect of the present invention, there is provided a position detecting sensor for detecting a position of a moving object by a magnetic field of a permanent magnet provided on the moving object. A position detection sensor,
A bottomed cylindrical main body case having an opening and having a depth dimension larger than the diameter of the opening; and an opening in the main body case
Together with it closed with tight sealed state a lid having a hole in its central portion, and a substrate mounted within said body case, and a magnetic sensor attached to the substrate, in order to display the operating state of the magnetic sensor wherein the indicator attached to the substrate, the lead wire drawn to outside from being connected to the magnetic sensor and the indicator lamp the lid, mounted in a tight sealed state into the holes of the lid, the front Stories a sealing member for sealing the outer periphery of the lead wire, et al provided in the main body case
To connect the inside and the outside of the body case
A window hole for injecting a brushing agent and an external
And a display window for confirming the display state of the indicator light from outside.

The position detecting sensor according to the second aspect of the present invention.
In the lid, the hole of the sealing member, and the display window
And a sealing O-ring attached thereto.

[0011]

Since the main body case has a bottomed cylindrical shape and the depth dimension is larger than the diameter of the opening, the opening is relatively small, and sealing by the lid and the sealing member is performed via the O-ring, respectively. It is easy and reliable and inexpensive. Potty
Is injected from the window of the main body case and filled inside.
After that, the display window is attached from outside and the window hole is sealed.
You. You can check the display status of the indicator lights from the display window.
Wear.

The magnetic sensor is operated by a magnetic field of a permanent magnet provided on an external moving object, and outputs a signal through a lead wire. In addition, the indicator light is turned on or off according to the operation state of the magnetic sensor, and the display state is externally confirmed 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 detecting sensor 1 of FIG.

The position detecting sensor 1 includes a main body case 1
1, lid 12, substrate 13, lead wire 14, bush 15,
It comprises a display window 16, a shield cover 17, and the like. The main body case 11 is made of a synthetic resin, and has a substantially oval bottomed cylindrical shape in cross section.

An opening 21 of the main body case 11 has a cover 1
A step 22 for mounting an O-ring 81 that seals between the main body case 11 and the main body case 11 is provided over the entire inner peripheral surface thereof. Engaging recesses 23 are provided at two places.

The inner peripheral surface of the main body case 11 functions as a guide for facilitating the insertion of the substrate 13 and is fixed between the inner peripheral surface 27 of the main body case 11 so as to prevent the inserted substrate 13 from moving. Substrate supporting ridges 2
4 are provided in parallel with each other.

At a position near the bottom 11a of the main body case 11, 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. A part 26 is provided.

The lid 12 is provided with an opening 21 of the main body case 11.
Is made of a synthetic resin of the same material as that of the main body case 11. The cover 3 has a hole 3 for inserting the bush 15 with a slightly tight fit.
1, a step portion 32 for mounting the O-ring 81 and a claw portion 33 which engages with each of the engaging concave portions 23 provided on the main body case 11 and functions as a retaining member are provided.

The substrate 13 has 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 in the reverse polarity is attached.

The substrate 13 is supported by a substrate support frame 44. The substrate support frame 44 is made of an elastic synthetic resin, and has a frame shape surrounding the periphery of the substrate 13. The substrate support frame 44 supports the substrate 13 by pressing the substrate 13 with a holding claw 45 provided on the substrate support frame 44.

The substrate supporting frame 44 is elastically sandwiched between the above-described substrate supporting ridges 24 and the peripheral wall 27 of the main body case 11, so that the substrate supporting frame 44 is
And the substrate 13 are fixed.

The substrate 13 has a reed switch 41
The lead wire 14 is connected by soldering to one end of the light-emitting diode 42 and one end of the light-emitting diode 42.
2 and is drawn out to the outside through the bush 15 attached. A binding band 46 is wound around the lead wire 14 on the inner surface side of the bush 15 to prevent the bush 15 from slipping outward.

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 12 for preventing the lid 12 from coming off is fitted;
A peripheral groove 52 for mounting an O-ring 83 for sealing between the bush 15 and the bush 15, a hole 53 for passing the lead wire 14,
Steps 54 for mounting an O-ring 84 for sealing the outer periphery of the lead wire 14 are provided respectively.

A bush 15 is provided with a jam nut 55 made of metal and an inner terminal cap 5 made of synthetic resin for mounting a tube 18 for jacket indicated by a chain line.
6, outer terminal cap 57, seal packing 58,
A ring washer 59 is provided.

The display window 16 is made of a transparent synthetic resin.
It has a columnar shape with a flange. 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 upper 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 27. The shield cover 17 is provided with a mounting bracket 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, the O-ring 83 is inserted into the hole 31 of the lid 12 and joined. An O-ring 84 is attached to this, the lead wire 14 is passed through, and the binding band 46 is tightened.

Then, with the O-ring 81 attached to the lid 12 first, the tip of the lead wire 14 is soldered to the substrate 13. 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 case 11.

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

According to the above-described 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 O-ring 81 and the O-ring 81 can be reduced and the shape of the portion to be sealed can be smooth, the sealing with the O-ring 81 is easy and reliable.

The space between the body case 11 and the display window 16, the cover body 12 and the bush 15, and the bush 15 and the lead wire 14 are securely sealed by O-rings 82, 83 and 84, 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 time.

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

According to the above-described embodiment, the components can be combined and integrated without using an adhesive, so that assembly is easy. In the above-described embodiment, the potting agent is injected into the main body case 11, which makes the board 13 more waterproof and more resistant to vibrations, but the injection of the potting agent is omitted. It is also possible to disassemble and reassemble in that case.

In the above 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 in addition to the 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, intrusion of water or oil into the main body case can be prevented for a long time.

According to the second aspect of the present invention, a position detecting sensor can be provided at low cost.

[Brief description of the drawings]

FIG. 1 is a sectional front view of a position detection 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 detecting sensor of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Position detection sensor 11 Main body case 12 Lid 13 Substrate 14 Lead wire 15 Bush (sealing member) 16 Display window 41 Reed switch (magnetic sensor) 42 Light emitting diode (indicator light) 81, 82, 83 O-ring (packing)

Claims (2)

(57) [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, the sensor having an opening and having a depth dimension larger than a diameter of the opening. a main body case a larger bottomed cylindrical of a lid having a hole at the center thereof with closing the opening of the body case in tight sealed state, a substrate mounted within said body case, the A magnetic sensor attached to the substrate; an indicator light attached to the substrate to display an operation state of the magnetic sensor; and a display sensor connected to the magnetic sensor and the indicator light and pulled out from the lid. and the lead wire, said the hole of the lid is attached by tight sealing condition, prior Symbol a sealing member for sealing the outer periphery of the lead, provided in the main body casing, inside and outside of the main body case
A window hole for injecting a potting agent that communicates with the portion, and a display window for externally checking the display state of the indicator light by being attached to the window hole of the main body case by being externally attached to the window hole. A position detection sensor comprising: 2. The position detecting sensor according to claim 1, wherein an O-ring for sealing is mounted on the cover, the hole of the sealing member , and the display window.