JP2000180289A - Oil leakage detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically detect oil leakage by constitution a detector of an oil sucking out part and electrodes confronted with the oil sucking out part and detecting oil leakage in response to the electrostatic capacity of the respective electrodes. SOLUTION: This detector is constituted of an oil sucking out part 2 sucking out oil, and a pair of electrodes 3, 4 confronted with each other sandwiching the oil sucking out part 2, to be in construction of a condenser. The electrodes 3, 4 are formed out of thin metallic plate, and electrically insulated between both. The oil sucking out part 2 is made of insulation material such as paper or sponge capable of sucking oil. The oil sucking out part 2 is raised in specific dielectric constant at absorbing oil, and the electrostatic capacity of the oil leak detector increases. Consequently, when the oil leakage detector 1 is provided on the part position apt to cause oil leakage and the electrostatic capacity increases over a fixed value, oil leakage is decided to be caused. By reducing a distance (t) between the electrodes 3, 4, or enlarging the area of the electrodes 3, 4, the change rate of the electrostatic capacity is enlarged, and the detecting accuracy can be raised.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil leak detector for electrically detecting an oil leak.

[0002]

2. Description of the Related Art Conventionally, there is a possibility that an oil leak may occur in a hydraulic device due to deterioration of a sealing material or the like, and there has been a demand for automatically detecting the oil leak. .

Accordingly, an object of the present invention is to provide an oil leak detector for automatically detecting an oil leak.

[0004]

According to a first aspect of the present invention, there is provided an oil sucking portion for sucking oil, and electrodes facing each other with the oil sucking portion interposed therebetween, and detects oil leakage according to the capacitance of each electrode. To do.

According to a second aspect of the present invention, in the first aspect, a holder is provided for accommodating each of the electrodes and the oil sucking portion, and an opening for exposing the oil sucking portion is formed in the holder.

In a third aspect based on the first or second aspect, each electrode and the oil absorbing portion are wound in a cylindrical shape.

According to a fourth aspect of the present invention, in any one of the first to third aspects, an oil receiving portion for storing hydraulic oil leaking from the hydraulic device is provided, and the respective electrodes and the oil sucking portion are mounted via the oil receiving portion. It was taken.

[0008]

According to the first aspect of the present invention, since the dielectric constant of the oil absorbing portion changes when oil permeates, the presence or absence of oil leakage can be determined according to the capacitance of the oil leakage detector. . Accordingly, it is possible to prevent the hydraulic device and its surroundings from being contaminated due to oil leakage, and to prevent malfunction of the hydraulic device due to insufficient hydraulic oil.

In the second aspect of the present invention, the accuracy of detecting an oil leak can be enhanced by arranging the opening of the retainer toward a portion of the hydraulic device, for example, where the oil leak easily occurs.

[0010] In the third aspect of the present invention, the structure in which each electrode and the oil sucking portion are wound in a cylindrical shape can increase the area of each electrode and increase the accuracy of detecting oil leakage.

In the fourth aspect of the invention, the hydraulic oil leaking from the hydraulic device is stored in the oil receiving portion and guided to the oil sucking portion, whereby the oil leak can be detected quickly.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

As shown in FIG. 1, the oil leak detector 1 has a capacitor structure including an oil sucking section 2 for sucking oil and a pair of electrodes 3 and 4 opposed to each other with the oil sucking section 2 interposed therebetween. ing. Each of the electrodes 3 and 4 is formed of a thin metal plate, and is electrically insulated between them. The oil absorbing portion 2 as a dielectric is an insulating material made of paper or sponge capable of absorbing oil.

When a voltage V is applied between the electrodes 3 and 4, the electric charge Q stored in the electrodes 3 and 4 is expressed by the following equation. Q = C × V (1) C is the capacitance, and the area of the electrodes 3 and 4 is S,
4 is t, and the relative permittivity of the oil absorbing portion 2 is ε, ε _0.
Is the vacuum dielectric constant (8.55 × 10 ⁻¹² ), the capacitance C is expressed by the following equation. C = ε ₀ × ε × S / t (2) When the oil absorbing portion 2 absorbs oil, the relative permittivity ε increases,
The capacitance C of the oil leak detector 1 increases. Therefore,
An oil leak detector is installed, for example, in a location where oil leaks easily occur in a hydraulic device, and when the capacitance C of the oil leak detector 1 increases beyond a predetermined value, it is determined that an oil leak has occurred. Can be.

By reducing the distance t between the electrodes 3 and 4 or increasing the area S of the electrodes 3 and 4, the capacitance C
, The detection rate can be increased.

The oil absorbing section 2 preferably has an isolation function between the electrodes 3 and 4 and an oil absorbing function, and has a dielectric constant sufficiently lower than that of oil. Note that the oil sucking section 2 may be a space without any inclusions.

In order to detect this oil leak, as shown in FIG.
And a microcomputer 20 that determines oil leakage according to the oscillation frequency of the pulse output from the oscillation circuit 10.

The oscillation circuit 10 repeats charging and discharging of the oil leak detector 1 via the resistors 11 and 12, and outputs a pulse having a cycle T and a frequency f according to the capacitance C of the oil leak detector 1. An IC 13 is provided. Assuming that the resistance values of the resistors 11 and 12 are R _A and R _B , the oscillation frequency f of the pulse output from the timer IC 13 is expressed by the following equation. f = 1.44 / [(R _A + 2R _B ) × C] (3) The microcomputer 20 determines that the oscillation frequency f of the pulse output from the timer IC 13 is lower than a predetermined value and is low, and the oil leaks. Turn on the detection output. By receiving the oil leak detection output and activating an alarm or the like, or automatically stopping the operation of the hydraulic device, the oil device is prevented from being contaminated by the oil leak, and It is possible to prevent malfunction of the hydraulic device due to lack of hydraulic oil and the like.

The circuit for detecting an oil leak is not limited to the above-mentioned digital detection system, but may be an analog detection system for detecting the capacitance between the electrodes 3 and 4, for example.

Further, as shown in FIG.
Is provided with a thin box-shaped case 5, and an opening 5 a through which the oil sucking portion 2 is exposed is formed at one end of the case 5. Note that openings may be formed at both ends of the case 5 to expose the oil sucking portion.

Each of the electrodes 3 and 4 is connected to the inner wall surface of the case 5 via an insulating portion 6, and two lead wires 7 and 8 connected to each of the electrodes 3 and 4 are taken out of the case 5. Note that a terminal, a socket, and the like may be provided in the case 5 instead of the lead wires 7 and 8. Further, as a retainer for housing the oil leak detector 1, the case 5 may be omitted and only the box-shaped insulating portion 6 may be provided.

In this case, by setting the opening of the case 5 to a portion of the hydraulic device, for example, where the oil leaks easily, the accuracy of detecting the oil leak can be increased.

Further, by extracting only the oil sucking portion 2 from the case 5 and replacing it, the oil leak detector 1 can be reused.

As shown in FIG. 4, a cylindrical oil receiving portion 2 is provided.
The oil receiving portion 21 is attached so as to cover the seal portion 24 of the hydraulic cylinder 22 and the rod 23, and the oil leak detector 1 housed in the thin box-shaped case 5 is bent to form the oil receiving portion 21. May be housed inside.

In this case, the seal portion 2 of the hydraulic cylinder 22
The oil leaking from 4 flows out between the oil receiving portion 21 and the rod 23 and is guided to the oil leak detector 1, so that the oil leak can be quickly detected.

As another embodiment, as shown in FIG. 5, each of the electrodes 3 and 4 and the oil sucking portion 2 of the oil leak detector 1 may be wound in a cylindrical shape with an insulating portion 9 interposed therebetween.

By winding each of the electrodes 3 and 4 in a cylindrical shape, the area of each of the electrodes 3 and 4 is enlarged, and the accuracy of detecting oil leakage can be increased.

As shown in FIG. 6, a semicircular oil receiving portion 31 is attached so as to cover the lower side of the seal portion 24 of the hydraulic cylinder 22 and the rod 23, and the oil leak detector 1 wound in a cylindrical shape is mounted. You may insert in the hole 32 opened in the oil receiving part 31.

In this case, the seal portion 2 of the hydraulic cylinder 22
The oil leaking from 4 flows out between the oil receiving portion 31 and the rod 23 and is guided to the oil leak detector 1, so that the oil leak can be detected quickly.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an oil leak detector showing an embodiment of the present invention.

FIG. 2 is a system diagram of the oil leak detector.

FIG. 3 is a perspective view of the oil leak detector.

FIG. 4 is a perspective view of a hydraulic cylinder and the like.

FIG. 5 is a perspective view of an oil leak detector according to another embodiment.

FIG. 6 is a perspective view of a hydraulic cylinder and the like.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Oil leak detector 2 Oil absorption part 3 Electrode 4 Electrode 5 Case 10 Oscillation circuit

Claims (4)

[Claims] 1. An oil leak, comprising: an oil sucking unit for sucking oil; and electrodes facing each other with the oil sucking unit interposed therebetween, wherein oil leak is detected in accordance with a capacitance of each of the electrodes. Detector. 2. The oil leak detection according to claim 1, further comprising a retainer for accommodating each of the electrodes and the oil sucking portion, wherein an opening is formed in the retainer to expose the oil sucking portion. vessel. 3. The oil leak detector according to claim 1, wherein each of the electrodes and the oil sucking portion is wound in a cylindrical shape. 4. An oil receiving portion for storing hydraulic oil leaking from a hydraulic device, wherein each of the electrodes and the oil sucking portion is mounted via the oil receiving portion. An oil leak detector according to one of the above.