JP3647182B2 - Contamination checker and hydraulic pressure detector - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a contamination checker and a hydraulic pressure detector that can be suitably used for the contamination checker.
[0002]
[Prior art]
In a machine using lubricating oil or hydraulic oil, contamination gradually increases in the oil, and if left unattended, the machine will be worn out and damaged. In order to prevent such wear and damage, various types of contamination checkers for monitoring the amount of contamination are known. For example, there are an electromagnetic type, a spectroscopic type, an irradiation light attenuation type, and the like.
[0003]
[Problems to be solved by the invention]
However, the conventional contamination checker has the following problems.
(A) Although the electromagnetic type can be used in-line and is simple and inexpensive, it can detect only contamination of a ferromagnetic material such as iron or nickel. That is, there is a problem that it is impossible to detect other metals such as copper, carbon in a diesel engine, sulfur content of mixed fuel, and inorganic or organic matter such as earth and sand entering from the outside.
(B) On the other hand, in the spectroscopic method, the irradiation light attenuation method, etc., all contamination can be inspected for each component. However, these are large-scale contamination checkers for the analysis room, which require a lot of space, require skill for inspection, are expensive, and cannot be used in-line.
[0004]
The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to provide a contamination checker that can detect contamination in oil in-line regardless of the material .
[0005]
[Means and effects for solving the problems]
In order to achieve the above object , the contamination checker according to the present invention will be described with reference to FIG. 1, for example. First, (a) a first hydraulic pressure detector for detecting hydraulic pressure information of the hydraulic circuit 3 4 a, (b) an attachment portion 43 attached to the hydraulic circuit 3, a hydraulic pressure detection portion 42, and provided between the attachment portion 43 and the hydraulic pressure detection portion 42. A hydraulic pressure introduction part 45 whose volume can be changed in accordance with the magnitude of the hydraulic pressure P2 from the introduced hydraulic pressure circuit 3, and a throttle between the attachment part and the liquid introduction part. The throttle is a clogging site due to contamination, and the hydraulic pressure detection unit 42 detects the hydraulic pressure information of the hydraulic pressure introducing unit 45, and (c) the first and second hydraulic pressures. Each of the hydraulic pressure information is received from the detectors 4a and 4b, a difference between the respective hydraulic pressure information is calculated, and a signal using this difference as contamination information in the hydraulic pressure circuit 3 is provided as an external signal. And an arithmetic unit 5 for outputting to the computer.
[0006]
According to said contamination checker, there exist the following effects. This will be described with reference to FIG. The second fluid pressure detector 4b has a fluid pressure introducing portion 45 whose volume can be changed according to the fluid pressure Po from the fluid pressure circuit 3. For this reason, every time the hydraulic pressure Po changes in the second hydraulic pressure detector 4b, the liquid in the hydraulic circuit 3 enters and exits the hydraulic pressure introducing section 45 through the attachment section 43. Therefore, if contamination is generated in the oil, the contamination mainly accumulates in the through hole 43a as the liquid enters and exits. On the other hand, the first hydraulic pressure detector 4a detects the hydraulic pressure information of the hydraulic circuit 3 as it is. Accordingly, the hydraulic pressure information detected by the first and second hydraulic pressure detectors 4a and 4b causes a time difference and a difference in hydraulic pressure. In the present invention, the arithmetic unit 5 calculates these differences, and outputs a signal that uses this difference as contamination information in the hydraulic circuit 3 to the outside. That is, according to the contamination checker described above , the conventional first hydraulic pressure detector 4a and the second hydraulic pressure detector having the hydraulic pressure introducing portion 45 whose volume can be changed according to the magnitude of the hydraulic pressure P2. With only a simple configuration composed of 4b and the computing unit 5, the amount of contamination in the liquid can be output to the outside regardless of the material. For example, various vehicles having the hydraulic circuit 3 are usually equipped with a computing unit such as a microcomputer. However, the computing unit 5 can be configured only by slightly upgrading such a computing unit.
[0014]
Further, the clogging can be promoted by providing the throttle 46 between the attachment portion 43 and the liquid introduction portion 45. That is, in the above contamination checker, when contamination occurs in the liquid, this can be detected early, remarkably and accurately.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic circuit diagram of a contamination checker. As shown in FIG. 1, a first hydraulic pressure detector 4a and a second hydraulic pressure detector 4b are mounted on the hydraulic circuit 3 from the hydraulic pressure source 1 to the hydraulic actuator 2. The first and second hydraulic pressure detectors 4a and 4b are electrically connected to a computing unit 5 made of, for example, a microcomputer, and the computing unit 5 can notify input information from the computing unit 5 to the outside. Etc., and an output device 6 such as a lighting lamp.
[0018]
As shown in FIG. 2, the second hydraulic pressure detector 4b has a diaphragm 42 as a hydraulic pressure detection unit having a bridge circuit 41 (which is not shown in the figure because FIG. 2 is a side view). The diaphragm 42 is a strain gauge type hydraulic pressure detector that detects the output value of the bridge circuit 41 when the diaphragm 42 receives the hydraulic pressure Po from the hydraulic circuit 3 and distorts according to the magnitude of the hydraulic pressure Po. However, details are as follows.
[0019]
The second hydraulic pressure detector 4b includes a hydraulic pressure detecting portion 42, which is the diaphragm 42, and a male screw formed on the outer periphery so as to be screwed into a female screw provided in a pipe line of the hydraulic circuit 3, and from the pipe line of the hydraulic circuit 3 to the inside. From the attachment part 43 having a through hole 43a formed toward the oil pressure detection part 42, and the oil pressure introduction part 45 that stores the elastic member 44 and is provided between the oil pressure detection part 42 and the attachment part 43. Composed. The elastic member 44 is selected and used so that oil does not enter the inside thereof.
[0020]
On the other hand, the first hydraulic pressure detector 4a is a hydraulic pressure detector obtained by removing the elastic member 44 from the configuration of the second hydraulic pressure detector 4b. That is, the first oil pressure detector 4a is a conventional oil pressure detector.
[0021]
Differences in operation of the first and second hydraulic pressure detectors 4a and 4b having the above-described configuration will be described with reference to FIG. The hydraulic pressure Po of the hydraulic circuit 3 constantly changes according to the load fluctuation of the hydraulic actuator 2. For this reason, the volume of the elastic member 44 of the second oil pressure detector 4b is constantly changing in response to the change of the oil pressure Po. As a result, every time the hydraulic pressure Po of the hydraulic circuit 3 changes, the volume of the hydraulic pressure introduction part 45 (specifically, the difference between the volume of the hydraulic pressure introduction part 45 itself and the volume of the elastic member 44) always changes. Accordingly, every time the hydraulic pressure Po of the hydraulic circuit 3 changes, the oil of the hydraulic circuit 3 enters and exits the hydraulic pressure introducing portion 45 through the through hole 43a of the attachment portion 43. When contamination occurs in the oil, the contamination mainly accumulates in the through holes 43a as the oil enters and exits. That is, when contamination occurs in the oil, the through holes 43a are gradually clogged. On the other hand, the first oil pressure detector 4a does not change the volume in the oil pressure introduction part 45 even if the oil pressure Po of the oil pressure circuit 3 changes. For this reason, there is no flow of oil in the through-hole 43a. Therefore, even if contamination is generated in the oil, the contamination is not clogged in the through-hole 43a. That is, it can be considered that the hydraulic pressure P1 in the hydraulic pressure introduction part 45 in the first hydraulic pressure detector 4a always matches the hydraulic pressure Po of the hydraulic circuit 3 both statically and dynamically. The first oil pressure detector 4a detects this oil pressure P1 (= Po). On the other hand, since the contamination of the second hydraulic pressure detector 4b is clogged in the through hole 43a as described above, the amount of oil per unit time flowing through the through hole 43a becomes the clogged amount whenever the hydraulic pressure Po of the hydraulic circuit 3 changes. It will change accordingly. That is, in the second oil pressure detector 4b, when the oil pressure Po of the oil pressure circuit 3 changes (especially when it changes suddenly), the oil pressure P2 in the oil pressure introduction part 45 is the same as the fluid pressure Po of the oil pressure circuit 3 (P2 = Po). Until a time delay Δt corresponding to the amount of clogging occurs. The second hydraulic pressure detector 4b detects such a hydraulic pressure P2 (≤Po). If the through hole 43a is completely clogged, the hydraulic pressure P2 detected by the second hydraulic pressure detector 4b becomes a very low value or cannot be detected (P2 <Po).
[0022]
In the first and second hydraulic pressure detectors 4b configured as described above, the following operational differences may occur. This will be described with reference to FIG. The hydraulic circuit 3 is not shown because it is included in the hydraulic pressure source 1 in FIG. 1 to restrict the maximum hydraulic pressure (relief pressure Po.max) of the entire hydraulic circuit 3 in order to prevent damage to the oil device due to high pressure. ). Therefore, when the hydraulic actuator 2 is overloaded, the hydraulic pressure Po of the hydraulic circuit 3 becomes the relief pressure Po.max. At this time, although depending on the relief valve, as shown in FIG. 4, a normal peak pressure Pop that exceeds the relief pressure Po.max is generated in the hydraulic circuit 3 (Pop> Po.max). The peak pressure Pop is detected as it is by the first oil pressure detector 4a (P1 = P1p = Pop), but the second oil pressure detector 4b absorbs some of the volume of the elastic member 44 and becomes low. Detected (P2 = P2p <Pop, P2p <P1p, and thus P1> P2).
[0023]
There are high-accuracy relief valves that do not generate the peak pressure Pop, and various elastic members 44 that completely absorb the peak pressure Pop can be prepared. For ease of explanation, the first embodiment and details will be described later. In this embodiment, it is assumed that the hydraulic pressure circuit 3 includes a relief valve that generates the peak pressure Pop, and the second hydraulic pressure detector 4b includes an elastic member 44 that does not completely absorb the peak pressure P2p (<P1p).
[0024]
Therefore, the computing unit 5 performs the following process (this is a first process in order to distinguish this from other processes whose details will be described later). The calculator 5 stores a reference hydraulic pressure Ps and a reference time Δts in advance. Accordingly, as shown in FIG. 5, the computing unit 5 raises and lowers the hydraulic pressure Po of the hydraulic circuit 3 when the hydraulic pressure P1 detected by the first hydraulic pressure detector 4a becomes the reference hydraulic pressure Ps (P1 = Ps). (2) The time Δt1 until the hydraulic pressure P2 detected by the hydraulic pressure detector 4b reaches the reference hydraulic pressure Ps (P2 = Ps) is calculated. As is apparent from the description of the operational differences between the first and second hydraulic pressure detectors 4a and 4b, the larger the time Δt1, the greater the amount of contamination accumulated in the through hole 43a of the attachment portion 43 (ie, the hydraulic pressure). The amount of contamination in the circuit 3 increases. Therefore, the time Δt1 is compared with the reference time Δts, and when “Δt1> Δts”, a meaning signal “the amount of contamination in the hydraulic circuit 3 is a dangerous amount” is input to the output unit 6.
[0025]
If the calculation is a one-time operation or an input to the output device 6, for example, when the oil pressure Po at the beginning or the start of the fall is substantially equal to the reference oil pressure Ps, there is a clogging corresponding to "Δt1>Δts". Even if it occurs, clogging cannot be detected because the time Δt1 is short. However, the computing unit 5 in the first embodiment is provided in-line in the hydraulic circuit 3 as shown in FIG. 1, and clogging corresponding to “Δt1> Δts” occurs because the first process is continuously performed. If this is the case, the event “Δt1> Δts” always appears in the plurality of operations. Specifically, since the change in the hydraulic pressure Po of the hydraulic circuit 3 due to the load fluctuation of the hydraulic actuator 2 occurs very frequently, the clogging occurs within a few seconds to a few minutes as long as the clogging corresponding to “Δt1> Δts” occurs. Can be detected.
[0026]
In the above comparison, the computing unit 5 can compute the clogging amount itself (that is, the contamination amount itself of the hydraulic circuit 3) based on the time Δt1 corresponding to “Δt1> Δts” and input it to the output unit 6. In this case, a correlation table or correlation function (contamination amount = f (Δt1)) between the time Δt1 and the amount of contamination is stored in the arithmetic unit 5 in advance, and the arithmetic unit 5 stores the time Δt1 in these tables and correlation functions. By fitting or substituting, a signal indicating the contamination amount itself in the hydraulic circuit 3 is input to the output device 6, and the output device 6 can output a specific contamination amount. In this first processing, the arithmetic unit 5 stores a plurality of n only for a time Δt1 corresponding to “Δt1> Δts”, obtains an average value Δt1a (Δt1a = (ΣΔt1) / n), and calculates the average value Δt1a. If used, a more accurate clogging amount can be input to the output device 6.
[0027]
Note that the computing unit 5 may perform processing such as the following second processing and third processing. This will be described with reference to FIGS.
[0028]
The second process is as follows. The calculator 5 stores a reference hydraulic pressure difference ΔPs1 in advance. Therefore, as shown in FIG. 6, the computing unit 5 determines the hydraulic pressure difference ΔP (= | P1) between the hydraulic pressure P1 detected by the first hydraulic pressure detector 4a and the hydraulic pressure P2 detected by the second hydraulic pressure detector 4b at the same time to. -P2 |) is calculated. As is apparent from the description of the operational differences between the first and second hydraulic pressure detectors 4a and 4b, the greater the hydraulic pressure difference ΔP, the greater the amount of contamination accumulated in the through hole 43a of the attachment portion 43 (ie, The amount of contamination in the hydraulic circuit 3 increases. Therefore, the hydraulic pressure difference ΔP is compared with the reference hydraulic pressure difference ΔPs1, and when “ΔP> ΔPs1”, a meaning signal “Contamination amount in the hydraulic circuit 3 is a dangerous amount” is output to the output device 6. input.
[0029]
In the case of a one-time calculation, even if a clogging corresponding to “ΔP> ΔPs1” occurs, the clogging may not be detected depending on the time to. However, since the calculator 5 of the first embodiment is provided in-line with the hydraulic circuit 3 as shown in FIG. 1 and continuously processes the second process, clogging corresponding to “ΔP> ΔPs1” at the same time to. As long as this occurs, an event of “ΔP> ΔPs1” always appears at a plurality of times of calculation. Specifically, since the change of the hydraulic pressure Po of the hydraulic circuit 3 due to the load fluctuation of the hydraulic actuator 2 occurs very frequently, as long as clogging corresponding to “ΔP> ΔPs1” occurs at the same time to, several seconds to several Clogging can be detected in minutes.
[0030]
In the above comparison, the calculator 5 can calculate the clogging amount itself (that is, the contamination amount of the hydraulic circuit 3 itself) based on the hydraulic pressure difference ΔP corresponding to “ΔP> ΔPs1” and input it to the output device 6. . In this case, the calculator 5 stores in advance a correlation table, a correlation function (contamination amount = f (ΔP)) of the hydraulic pressure difference ΔP and the amount of contamination, and the calculator 5 stores the hydraulic pressure in the table and the correlation function. By fitting or substituting the difference ΔP, a signal indicating the contamination amount itself in the hydraulic circuit 3 is input to the output device 6, and the output device 6 can output a specific contamination amount. In this second process, the computing unit 5 stores a plurality of hydraulic pressure differences ΔP corresponding to “ΔP> ΔPs1”, obtains an average value ΔPa (ΔPa = (ΣΔP) / n), and calculates the average value ΔPa. If is used, a more accurate clogging amount can be input to the output device 6.
[0031]
The third process is as follows. The calculator 5 stores a reference hydraulic pressure difference ΔPs2 in advance. Therefore, as shown in FIG. 7, regardless of the time, the arithmetic unit 5 is connected to the maximum hydraulic pressures P1, P2 (that is, peak pressure P1 (= P1p), peak pressure P2) from the first and second hydraulic pressure detectors 4a, 4b. (= P2p)), the hydraulic pressure difference ΔP (= | P1−P2 |) is calculated. As is apparent from the description of the operational differences between the first and second hydraulic pressure detectors 4a and 4b, the greater the hydraulic pressure difference ΔP, the greater the amount of contamination accumulated in the through hole 43a of the attachment portion 43 (ie, The amount of contamination in the hydraulic circuit 3 increases. Therefore, the hydraulic pressure difference ΔP is compared with the reference hydraulic pressure difference ΔPs1, and when “ΔP> ΔPs2”, a meaning signal “Contamination amount in the hydraulic circuit 3 is a dangerous amount” is output to the output device 6. input.
[0032]
In the third process, clogging basically corresponding to “ΔP> ΔPs2” can be detected even by a single calculation. However, the computing unit 5 of the first embodiment is provided in-line in the hydraulic circuit 3 as described above, and in order to continuously perform the third process, only a plurality n of hydraulic differences ΔP corresponding to “ΔP> ΔPs2” are stored. These are averaged ΔPa (= (ΣΔP) / n), and if this average value ΔPa is used, a more accurate clogging amount can be input to the output device 6.
[0033]
Hereinafter, other examples (a) to (g) will be listed.
[0034]
(A) The computing unit 5 does not need to perform each of the first to third processing examples individually, and after calculating some or all of them sequentially, for example, calculates an average value and a median value, The calculation result may be input to the output device 6. This further improves the detection accuracy. Alternatively, the switching signal may be manually input to the arithmetic unit 5, and each signal resulting from each calculation may be individually input to the output unit 6, and may be individually output from the output unit 6 to the outside in an appropriate format. Good.
[0035]
(B) In the first embodiment, each of the first and second hydraulic pressure detectors 4a and 4b is provided one by one, but a plurality may be provided. In this way, detection accuracy is improved. In particular, it is desirable to provide a plurality of second hydraulic pressure detectors 4a. In addition, the second hydraulic pressure detector 4b is installed at each location of the hydraulic circuit 3, so that the amount of contamination at each installed location can be grasped. Further, the first and second oil pressure detectors 4a and 4b do not need to be the same type as in the first embodiment.
[0036]
(C) As shown in FIG. 8, the second hydraulic pressure detector 4 b desirably has a throttle 46 between the attachment portion 43 and the hydraulic pressure introduction portion 45. In this way, clogging due to contamination can be promoted, and the amount of contamination can be detected at an early stage. The shape of the diaphragm 46 is preferably shaped into a taper shape such that the opening area gradually increases toward the hydraulic pressure introduction portion 45 side, for example, so that once clogged contamination does not easily leave the clogged portion. It is desirable to provide a hooked portion such as irregularities on the inner wall of the diaphragm 46. In addition, by providing a plurality of second hydraulic pressure detectors 4b having throttles 46 having different inner diameters in the hydraulic circuit 3, the computing unit 5 can perform detection for each size of the contamination, and the detection can be performed in a wider range and with higher accuracy. You can do it.
[0037]
(D) In FIG. 2 of the first embodiment, the second hydraulic pressure detector 4b is configured such that the elastic member 44 is floated on the hydraulic pressure introducing portion 45. For example, as shown in FIG. A ring-shaped elastic member 44 inserted into the inner periphery of the rubber may be used (for example, a rubber O-ring). The second hydraulic pressure detector 4b may have the same configuration as an accumulator as shown in FIG. That is, as shown in FIG. 10, the hydraulic pressure introduction part 45 is divided into two chambers, that is, an attachment part 43 side and a hydraulic pressure detection part 42 side by an elastic member 44 that can be expanded and contracted, and the hydraulic pressure detection part 42 side chamber is air-conditioned. Seal with a gas such as. In this way, when the hydraulic pressure Po of the hydraulic circuit 3 changes, the elastic member 44 transmits the hydraulic pressure Po to the chamber on the side of the hydraulic pressure detection unit 42 on the hermetic side in response to the change in the hydraulic pressure, and the hydraulic pressure detection unit 42 has the hydraulic pressure P2. Is detected. On the other hand, the flow of oil is generated in the through hole 43a, and clogging according to the amount of contamination occurs.
[0038]
(E) In FIG. 2 of the first embodiment, the second hydraulic pressure detector 4b has the elastic member 44 loosely fitted in the hydraulic pressure introducing portion 45. However, as shown in FIG. A through hole may be provided, and a damper plate 47 whose outer periphery is sealed may be fitted into the hole. In this way, each time the hydraulic pressure Po of the hydraulic circuit 3 changes, the damper plate 47 vibrates inward and outward, and the oil in the hydraulic circuit 3 enters and exits the hydraulic pressure introduction part 45. That is, the damper plate 47 provides the same effect as the elastic member 44.
[0039]
(F) Although the second hydraulic pressure detector 4b stores the elastic member 44 in each of the above-described embodiments, the rigidity of the diaphragm 42 serving as a hydraulic pressure detection unit is not stored in the elastic member 44, and the diaphragm of the first hydraulic pressure detector 4a is used. It may be significantly weaker than the rigidity of 42 and distorted greatly when subjected to the hydraulic pressure Po.
[0040]
(G) Although the second hydraulic pressure detector 4b is a strain gauge type hydraulic pressure detector in each of the above-described embodiments, the second hydraulic pressure detector 4b may be a Bourdon tube type hydraulic pressure detector that is capable of electrically inputting detected hydraulic pressure information to the calculator 5. Good. This is because the Bourdon tube bends in accordance with the hydraulic pressure Po of the hydraulic circuit 3 and is a hydraulic pressure detector that converts this deflection amount into hydraulic pressure. That is, in the Bourdon tube type hydraulic pressure detector, the oil of the hydraulic circuit 3 enters and exits the Bourdon tube every time the oil pressure Po of the hydraulic circuit 3 changes. That is, the Bourdon tube has the same volume change effect as the elastic member 44. In the Bourdon tube type hydraulic detector, it is desirable to provide the restrictor 64 at a portion where the Bourdon tube is attached to the hydraulic circuit 3 to promote clogging due to contamination.
[Brief description of the drawings]
FIG. 1 is a schematic circuit diagram of a contamination checker according to an embodiment.
FIG. 2 is a side view of a partial cross section of a second hydraulic pressure detector.
FIG. 3 is a graph showing a difference between detected hydraulic pressures by first and second hydraulic pressure detectors.
FIG. 4 is a graph showing a difference between detected peak oil pressures by the first and second oil pressure detectors.
FIG. 5 is a graph illustrating a first control example.
FIG. 6 is a graph illustrating a second control example.
FIG. 7 is a graph illustrating a third control example.
FIG. 8 is a side view of a partial cross section of another second hydraulic pressure detector.
FIG. 9 is a side view of a partial cross section of another second hydraulic pressure detector.
FIG. 10 is a side view of a partial cross section of another second hydraulic pressure detector.
FIG. 11 is a side view of a partial cross section of another second hydraulic pressure detector.
[Explanation of symbols]
3 Fluid pressure circuit 4a 1st fluid pressure detector 4b 2nd fluid pressure detector 42 Fluid pressure detection unit 43 Mounting portion 45 Fluid pressure introduction portion 46 Throttle 5 Calculator P1, P2 Fluid pressure P1p, P2p Peak fluid pressure ΔP Fluid Pressure difference Ps Reference fluid pressure t0 time Δt1 time

Claims (1)

(a) a first fluid pressure detector for detecting fluid pressure information of the fluid pressure circuit; (b) an attachment portion attached to the fluid pressure circuit; a fluid pressure detection portion; and a fluid pressure detection from the attachment portion. provided until part and a liquid pressure introducing portion which is a changeable volume according to the magnitude of the hydraulic pressure from the hydraulic circuit, which is introduced from the mounting portion, further, the attachment portion and the liquid A second hydraulic pressure detector having a throttle between the inlet and the throttle, the throttle being a clogging site due to contamination, and detecting hydraulic pressure information of the hydraulic pressure inlet by the hydraulic pressure detector; 1. An arithmetic unit that receives each hydraulic pressure information from the second hydraulic pressure detector, calculates a difference between the respective hydraulic pressure information, and outputs a signal that uses this difference as contamination information in the hydraulic circuit to the outside. Contamination checker characterized by having.

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