JP2019184398A - Position detector and waterproof structure of the same - Google Patents

Abstract

To provide a waterproof structure of a position detector which can prevent water from entering from the outside into the inside of a shaft protecting part and can also prevent an accordion shaft protecting part from winding around a stretchy movable shaft.SOLUTION: A waterproof structure 5 of a position detector 10 includes: a stretchy movable shaft 1; an accordion shaft protecting part for protecting the stretchy movable shaft 1 by coating the shaft; and a breather-pipe 3 for sucking and discharging outside air in association with the expansion and contraction of the stretchy movable shaft 1, the breather-pipe 3 having a vent filter 4 for preventing water absorption and transmitting gas.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a position detector and a waterproof structure thereof, and more particularly, to a waterproof technique for a position detector provided with a telescopic movable shaft for detecting a stroke in a linear direction used in the steel field and the like.

  Stroke detectors are used to detect linear strokes for horizontal operation control, such as in steel material handling equipment in heating furnaces, and are particularly positioned in humid environments, steam generating environments, and high temperature / dusty environments. Used for detection. In the stroke detector, the expansion / contraction amount of the shaft that can be expanded and contracted by the ball screw is converted into a rotation amount and detected.

  FIG. 5 is a half sectional view showing a configuration example of a conventional stroke detector. As shown in the figure, in the conventional stroke detector 510, the ball screw 56 is used to convert the expansion / contraction amount of a shaft 51 that can be expanded and contracted (expandable movable shaft) into a rotation amount in the angle sensor 57. The telescopic movable shaft 51 is covered and protected by a shaft protector 52 having a bellows shape. A breather pipe 53 is provided to change the internal volume of the shaft protector 52 when the telescopic movable shaft 51 expands and contracts. Since the outside air is sucked and exhausted by the breather pipe 53, the shaft protector 52 can be driven without being in close contact with or entangled with the telescopic movable shaft 51 even if the internal volume change in the shaft protector 52 occurs.

  Conventionally, a technical proposal has been made for the stroke detector. For example, in Patent Document 1 described later, as a horizontal motion stroke detector for controlling the horizontal motion stroke of a walking beam heating furnace, an annular oilless bush is provided on the inner peripheral surface of the outer case, and the inner peripheral surface is used as a slide rod. A slide that has an inner diameter that can be contacted, and annular dust seal retainers are arranged on both sides of the outer case. A configuration with a mechanism is disclosed. Thereby, even if grease is not supplied, it has lubricity, and it is possible to suppress slide mechanism breakage and stroke failure.

Japanese Patent Application Laid-Open No. 2012-136739 “Sliding Mechanism of Horizontal Motion Stroke Detector under High Temperature and High Dust”

  Now, the environment in which the conventional stroke detector 510 shown in FIG. 5 is used is a humid environment. There is a problem in that moisture is inevitably accumulated inside the detector 510 and corrosion is caused by the intake and exhaust of the outside air by the breather pipe 53 in such an environment. As a means for solving this problem, there is a configuration in which the breather pipe 53 is removed.

  FIG. 6 is a half sectional view showing a configuration example in which a breather pipe is removed from a conventional stroke detector. As shown in the figure, the stroke detector 610 is provided with a plug 63 in place of the breather pipe, thereby preventing moisture inhalation (intrusion) from the outside. However, since the inside of the shaft protection portion 62 is sealed in such a configuration, when the telescopic movable shaft 61 is extended, the bellows-shaped shaft protection portion 62 is in close contact with or wound around the telescopic movable shaft 61. Will cause problems.

  Therefore, the problem to be solved by the present invention is to eliminate the problems of the prior art, prevent moisture from entering the shaft protector from outside, and wind the bellows-shaped shaft protector around the telescopic movable shaft. It is also possible to provide a waterproof structure of the position detector that can prevent the above.

  As a result of studying the above problems, the present inventor has found that the problem can be solved by using a vent filter in the breather pipe, and based on this, the present invention has been completed. That is, the invention claimed in the present application as means for solving the above-described problems, or at least the invention disclosed is as follows.

[1] A waterproof structure for a position detector having a telescopic movable shaft, comprising: a shaft protector that covers and protects the telescopic movable shaft; and a breather pipe that intakes and exhausts outside air when the telescopic movable shaft expands and contracts. A waterproof structure for a position detector, wherein the breather pipe is provided with a vent filter that blocks moisture absorption while allowing gas to flow therethrough.
[2] A position detector comprising the waterproof structure according to [1].

  Since the position detector of the present invention and the waterproof structure thereof are configured as described above, according to these, even if the use environment is a humid environment, it is possible to prevent moisture from entering inside the shaft protector. Further, it is possible to prevent winding of the bellows-shaped shaft protecting portion around the telescopic movable shaft.

It is a principal part half sectional view which shows the waterproof structure of the position detector of this invention. FIG. 2 is an enlarged view of a circle shown in FIG. 1. FIG. 2 is a half cross-sectional view illustrating a configuration of a position detector including the waterproof structure illustrated in FIG. 1. It is an enlarged view which shows the structure of the breather pipe in the conventional stroke detector shown in FIG. It is a half sectional view showing a configuration example of a conventional stroke detector. It is a half cross-sectional view showing a configuration example in which a breather pipe is removed from a conventional stroke detector.

Hereinafter, the present invention will be described in detail with reference to the drawings.
FIG. 1 is a half sectional view of a principal part showing a waterproof structure of a position detector of the present invention. Also,
FIG. 2 is an enlarged view of the circular portion shown in FIG. 1, and FIG. 3 is a half sectional view showing the configuration of the position detector having the waterproof structure shown in FIG. As shown in these figures, the waterproof structure 5 of the present position detector is a waterproof structure in the position detector 10 having the telescopic movable shaft 1, and includes an accordion-shaped shaft protection unit 2 that covers and protects the telescopic movable shaft 1, and expansion and contraction. The main configuration is that a breather pipe 3 that sucks and discharges outside air accompanying expansion and contraction of the movable shaft 1 is provided, and the breather pipe 3 includes a vent filter 4 that blocks moisture absorption while allowing gas to flow. .

  The vent filter 4 is a filter that makes the sealed container and the structure waterproof and dustproof while ensuring ventilation and maintaining the pressure adjustment function. It is widely used for various sensors for automobiles, gas sensors, liquid containers, microphone covers for acoustic equipment, and the like. The vent filter is made of a porous membrane having a structure that allows gas to pass while blocking moisture. In the present invention, a vent filter already on the market can be appropriately used for a waterproof structure.

  With this configuration, in the waterproof structure 5 of the present position detector, moisture absorption from the outside is blocked by the vent filter 4 provided in the breather pipe 3, while gas is allowed to flow. Therefore, moisture intrusion into the shaft protector 2 is effectively prevented, and internal corrosion is prevented. At the same time, since the outside air is sucked and exhausted through the vent filter 4, the shaft protector 2 may be in close contact with or wound around the telescopic movable shaft 1 even if the internal volume in the bellows-shaped shaft protector 2 changes. There is no.

  FIG. 4 is an enlarged view showing the structure of the breather pipe in the conventional stroke detector shown in FIG. As shown in the drawing, in the prior art, the breather pipe 53 is provided with only a stitch plate 58 for preventing foreign matter from entering. Naturally, the penetration of moisture from the outside cannot be prevented with the stitch plate 58 alone. Water intrusion can be prevented by the waterproof structure 5 of the present invention having the breather pipe 3 provided with the vent filter 4. In addition, although not shown in FIG. 1 etc., it is good also as a structure which uses a stitch board together also in the waterproof structure 5 of this invention. Further, the position detector 10 itself provided with the waterproof structure 5 described above is also within the scope of the present invention.

  According to the position detector of the present invention and the waterproof structure thereof, even when the usage environment is a humid environment, moisture can be prevented from entering from the outside into the shaft protector, and the telescopic movable shaft of the bellows-shaped shaft protector It is also possible to prevent winding around. Therefore, it is an invention with high industrial applicability in the field of manufacture and use of position detectors for high humidity environments such as the steel field, particularly in the field of manufacture and use of stroke detectors, and all related fields.

DESCRIPTION OF SYMBOLS 1 ... Telescopic movable shaft 2 ... Shaft protection part 3 ... Breather pipe 4 ... Vent filter 5 ... Waterproof structure 6 of position detector ... Ball screw 7 ... Angle sensor 10 ... Position detector 51, 61 ... Telescopic movable shaft 52, 62 ... Shaft protector 53 ... Breather pipe 56, 66 ... Ball screw 57, 67 ... Angle sensor 58 ... Knitting plate 510, 610 ... Stroke detector 63 ... Plug

Claims (2)

A waterproof structure for a position detector having a telescopic movable shaft, comprising: a shaft protection portion that covers and protects the telescopic movable shaft; and a breather pipe that sucks and exhausts outside air that accompanies expansion and contraction of the telescopic movable shaft. The position detector is provided with a vent filter that blocks moisture absorption while allowing gas to flow. A position detector comprising the waterproof structure according to claim 1.