JP3940032B2 - Fluid cleaning device for fluid pressure circuit - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fluid cleaning device of a fluid pressure circuit capable of sensing a filter clogging state.
[0002]
[Prior art]
When a breaker as an attachment is attached to the hydraulic excavator instead of a bucket and this breaker is operated by a hydraulic circuit, as shown in FIG. 4, in the return line 3 for returning oil from the breaker 1 to the tank 2, A return line filter 5 is provided on the upstream side of the original main filter 4 of the hydraulic circuit, and the return line filter 5 collects contamination that has entered the breaker 1 from a seal portion provided on the chisel piston of the breaker 1. Thus, this contamination is prevented from entering the main pump 6 through the tank 2.
[0003]
In particular, in the upward breaker work in the tunnel, the chisel piston of the breaker 1 is also in an upward posture, and contamination that has occurred due to rock crushing may fall on the seal portion and the like, so that contamination enters the breaker 1. Therefore, in order to prevent damage to the main pump 6 due to the entry of contamination, it is necessary to additionally mount the high-performance return line filter 5 on the return line 3 of the attachment circuit.
[0004]
[Problems to be solved by the invention]
In such breaker work, the filter element replacement time is shorter than in normal work and the frequency of filter element replacement is high, but the user cannot accurately check the filter clogging condition, and the return line An appropriate element replacement time of the filter 5 is often missed, and there is a concern that the main pump 6 may be damaged due to a decrease in the purification performance of the return line filter 5 after the replacement time.
[0005]
The present invention has been made in view of these points, and an object of the present invention is to provide a fluid purification device for a fluid pressure circuit that can appropriately cope with a filter clogged state.
[0006]
[Means for Solving the Problems]
The invention described in claim 1 detects a clogging detection signal by detecting a filter clogging state from a filter provided in a return passage from a fluid pressure actuator and a differential pressure between an inlet side and an outlet side of the filter. Output clogging detection means, malfunction check means for cutting malfunction signal of clogging detection means due to pulsation on the inlet side from the filter, and continuous clogging detection signal exceeding a set fixed time after malfunction check means A fluid pressure having an output means having a counting means for counting and displaying the number of clogging detection signals that are output as output from the clogging sensing means and increases as the contamination level of the working fluid is deteriorated a fluid purification apparatus circuit, clogging sensing means, outputs a clogging sensing signal by sensing filter plugging state from the differential pressure between the inlet side and the outlet side of the filter Then, the malfunction check means cuts the malfunction signal of the clogging detection means due to the pulsation on the inlet side from the filter, and the output means outputs a continuous clogging detection signal, so that the filter inlet during the operation of the fluid pressure actuator Even when pulsation occurs on the side, a true filter clogging state can be sensed, and the filter clogging state can be appropriately dealt with. From the number of transmissions of the clogging detection signal that increases with the deterioration of the contamination level of the working fluid, the contamination level of the working fluid can be grasped and the filter element replacement time can be predicted.
[0007]
According to a second aspect of the present invention, the malfunction check means in the fluid pressure cleaning device of the fluid pressure circuit according to the first aspect is provided by the clogging sensing means based on the time length of the clogging sensing signal output from the clogging sensing means. It is a timer that checks the malfunction and cuts the pulsation signal for a shorter time than the set fixed time , and even if the clogging detection means malfunctions due to the pulsation that occurs when the fluid pressure actuator operates, By using a simple timer to cut a short-time clogging detection signal generated by pulsation as a malfunction signal of the clogging detection means, it is possible to easily prevent the output means from malfunctioning.
[0008]
According to a third aspect of the present invention, the output means in the fluid purifier of the fluid pressure circuit according to the first or second aspect is operated by a clogging detection signal passed through the malfunction check means to warn the filter clogging state. This is a clogging warning means, and the clogging warning means is activated by the clogging detection signal that has passed through the malfunction check means to warn the filter clogging status, so that the filter clogging status can be confirmed accurately and at an appropriate time. You can change the filter.
[0009]
According to a fourth aspect of the present invention, there is provided a filter from a differential pressure between a filter provided in a return passage from a fluid pressure actuator operated by a working fluid pressurized and supplied from a pump, and an inlet side and an outlet side of the filter. Clogging detection means that detects a clogging condition and outputs a clogging detection signal, and the capacity of the fluid pressure circuit is reduced to limit the operation of the fluid pressure actuator in response to the clogging detection signal from the clogging detection means which has a reduced capacity function of, and a controller with a counting means for displaying a count of the number of times of clogging sensing signal increases with the deterioration degree of contamination conditions of the working fluid originating from clogging sensing means a fluid cleaning system of the fluid pressure circuit that, the controller received a clogging sensing signal from clogging sensing means, by reducing the ability of the fluid pressure circuit Since the necessary operation of the hydraulic actuator can not be obtained, counting from this state, the filter plugging state can be reliably recognized, appropriate can address filter plugging state, also, the number of originations of clogging sensing signal By counting and displaying by means, it is possible to grasp the contamination level status of the working fluid from the number of clogging detection signals that increase with the deterioration of the contamination status of the working fluid, and predict the filter element replacement time Can do.
[0010]
According to a fifth aspect of the present invention, the controller in the fluid purifier of the fluid pressure circuit according to the fourth aspect reduces the rotational speed of the engine for driving the pump in response to the clogging detection signal from the clogging detection means. The controller that received the clogging detection signal from the clogging detection means reduces the rotational speed of the pump drive engine, and the pump discharge pressure and pump discharge flow rate are reduced. Since the required actuation force and actuation speed of the fluid pressure actuator cannot be obtained, the filter clogging state can be reliably recognized from such a state, and the filter clogging state can be appropriately dealt with.
[0011]
According to a sixth aspect of the present invention, the controller of the fluid pressure circuit of the fluid pressure circuit according to the fourth or fifth aspect is configured so that the controller detects the clogging detection means based on the time length of the clogging detection signal output from the clogging detection means. Is equipped with a timer function that cuts the pulsation signal for a shorter time than the set fixed time , and the clogging detection means malfunctions due to the pulsation that occurs when the fluid pressure actuator operates. Even if the controller is affected by the pulsation, the controller function affected by the pulsation can be controlled by cutting the short-time clogging detection signal generated by the pulsation as a malfunction signal of the clogging detection means. Can be prevented.
[0012]
According to a seventh aspect of the present invention, the filter in the fluid purification device of the fluid pressure circuit according to any one of the first to sixth aspects causes the exchangeable filter element to communicate with the inlet side and the outlet side of the filter element. The bypass passage, a bypass valve provided in the bypass passage and opened when the differential pressure between the inlet side and the outlet side of the filter element is equal to or higher than the relief set pressure, and the differential pressure between the inlet side and the outlet side of the filter element are An indicator that transmits a clogging detection signal when the pressure exceeds the relief set pressure.When the differential pressure between the inlet side and the outlet side of the filter element exceeds the relief valve set pressure, the bypass valve opens. Since the filter element is bypassed by the bypass passage, the filter element is damaged by excessive differential pressure. Together to be prevented, since the bypass valve is clogged sensing signal from the indicator for each opened is transmitted, you can check the operating status of the bypass valve from the outside.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the embodiment shown in FIGS.
[0014]
FIG. 1 shows an embodiment of a hydraulic circuit as a fluid pressure circuit in which a fluid cleaning device 11 for cleaning a working oil as a working fluid is incorporated.
[0015]
This hydraulic circuit includes a main pump 13 and a pilot pump 14 as pumps driven by an engine 12 mounted on a hydraulic excavator or the like, and the suction port of the main pump 13 passes through the hydraulic oil suction passage 15 to The discharge port of the main pump 13 is communicated with the supply port of the control valve 18 through the hydraulic oil supply passage 17, and one of a plurality of spools 19 constituting the control valve 18 is connected to the tank 16. The passed port communicates with a hydraulic oil supply port of a breaker 22 as a fluid pressure actuator, which is an attachment of a hydraulic excavator, through a hydraulic oil supply passage 21.
[0016]
The breaker spool 19 is displaced by a pilot pressure supplied from the pilot pump 14 and controlled by a foot-operated foot valve 23, and controls the amount of hydraulic oil supplied from the main pump 13 to the breaker 22 according to the amount of displacement. .
[0017]
Between the passage 21 communicated with the hydraulic oil supply port of the breaker 22 and the return passage 24 drawn from the hydraulic oil discharge port of the breaker 22, communication is provided by a passage 25, and a check valve is provided in the passage 25. A built-in electromagnetic switching valve 26 and a relief valve 27 are provided, and an electromagnetic switching valve 28 with a built-in check valve is provided in the return passage 24.
[0018]
In the return passage 24 from the breaker 22 to the hydraulic oil tank 16, a return line filter 31, a back pressure check valve 32, a main filter 33, and an oil cooler 34 are provided as filters.
[0019]
As shown in FIG. 2, the fluid purifier 11 is configured such that the inlet side and the outlet side of the filter element 35 that can be replaced by the return line filter 31 can communicate with each other by a bypass passage 36. A valve 37 is provided.
[0020]
The bypass valve 37 is opened when the differential pressure between the inlet side and the outlet side of the filter element 35 is equal to or higher than the relief set pressure set by the spring 38, and is bypassed by the bypass passage 36 from the inlet side of the filter element 35. Since the outlet side communicates with the bypass, it is possible to prevent the filter element 35 from being damaged by an excessive differential pressure.
[0021]
Further, an indicator 39 as a clogging detecting means is connected in parallel with the bypass valve 37. The indicator 39 is a differential pressure indicator that detects a state in which the differential pressure between the inlet side and the outlet side of the filter element 35 is equal to or higher than the relief set pressure as a filter clogged state and transmits a clogging detection signal.
[0022]
Since the clogging detection signal is transmitted from the indicator 39 every time the bypass valve 37 is opened, the operating state of the bypass valve 37 can be confirmed from the outside.
[0023]
Further, as shown in FIG. 1, the indicator 39 is connected to a timer 41 as malfunction check means. The timer 41 has a function of cutting a malfunction signal output from the indicator 39 due to the pulsation of hydraulic pressure generated on the inlet side from the return line filter 31 during the hitting operation of the breaker 22.
[0024]
In other words, the timer 41 checks the malfunction of the indicator 39 based on the time length of the clogging detection signal output from the indicator 39, and outputs an output signal for a continuous input signal that exceeds a set fixed time. And function so as not to output an output signal for an input signal of a shorter time. Therefore, it is possible to cut the pulsation signal during the hitting operation of the breaker 22 and output only the continuous clogging detection signal.
[0025]
The timer 41 is provided with a display 42 as output means for outputting a continuous clogging detection signal that has passed through the timer 41. The indicator 42 is a clogging warning means that operates in accordance with a clogging detection signal output from the timer 41 and warns of a filter clogging state. The clogging warning means includes a lamp, a buzzer, a voice generator, and the like.
[0026]
Next, the function and effect of the embodiment shown in FIGS. 1 and 2 will be described.
[0027]
When the breaker operation is started, the electromagnetic switching valves 26 and 28 are switched to the communication position, and the hydraulic oil discharged from the main pump 13 is controlled by the control valve 18 and supplied to the breaker 22, and from the breaker 22 to the return passage 24 Is returned to the hydraulic oil tank 16 via the return line filter 31, the back pressure check valve 32, the main filter 33, and the oil cooler.
[0028]
Since the breaker 22 is used in an environment in which dust or the like is scattered, dust or the like that has entered the hydraulic circuit from the breaker 22 becomes contamination in the return passage 24. Such contamination is removed from the oil by the return line filter 31 in the return oil.
[0029]
Therefore, this return line filter 31 can reduce the burden on the main filter 33 located further downstream, and contamination in the return oil that has bypassed the main filter 33 reaches the main pump 13 via the hydraulic oil tank 16. Fear can be prevented.
[0030]
Accordingly, the return line filter 31 is more likely to clog the return line filter 31 than the main filter 33, and the filter element replacement of the main filter 33 may be performed periodically. Occasional and frequent replacement.
[0031]
At this time, the filter element replacement time of the return line filter 31 can be accurately confirmed by the indicator 39, the timer 41, and the display 42.
[0032]
That is, as the clogging of the filter element 35 progresses, the differential pressure between the inlet side and the outlet side of the filter element 35 increases, and when the relief set pressure of the bypass valve 37 is exceeded, the indicator 39 detects the filter level from the differential pressure. A clogging detection signal is transmitted by detecting the clogging state.
[0033]
At the same time, the bypass valve 37 is opened and the inlet side and the outlet side of the filter element 35 are bypassed by the bypass passage 36, so that the oil in the return passage 24 bypasses the filter element 35 without passing through the filter element 35. The passage 36 is bypassed and returned to the hydraulic oil tank 16.
[0034]
Upon receiving this clogging detection signal, the timer 41 checks the malfunction of the indicator 39 due to the pulsation of the hydraulic pressure in the return passage 24 accompanying the blow operation of the breaker 22, and in the return passage 24 generated during the breaker operation. Even if the indicator 39 malfunctions due to pulsation of hydraulic pressure, the simple timer 41 may cut the short-time clogging detection signal generated by pulsation as a malfunction signal of the indicator 39, which may cause the display 42 to erroneously display. It can be easily prevented.
[0035]
The indicator 42 receives a clogging detection signal that has passed through the timer 41 and displays a warning about the continuous filter clogging status, so that the operator can accurately check the filter clogging status with this indicator 42 and The filter element 35 can be replaced at an appropriate time. That is, it is possible to detect a true filter clogging state and appropriately cope with the filter clogging state.
[0036]
Thus, the clogging of the filter element 35 can be confirmed by the clogging detection signal from the indicator 39, and even if the bypass valve 37 of the bypass passage 36 is opened due to the pulsation of the hydraulic pressure generated when the breaker is hit, 41 works, and the malfunction of the indicator 39 can be cut off. For this reason, the user can replace the filter element 35 with error-free filter element replacement time information, and can prevent damage to the main pump 13 due to contamination in the hydraulic oil.
[0037]
Next, FIG. 3 shows another embodiment. In addition, the same code | symbol is attached | subjected to the part similar to embodiment shown in FIG. 1, and the description is abbreviate | omitted.
[0038]
A return line filter 31 as a filter is provided in a return passage 24 from a breaker 22 as a fluid pressure actuator that is operated by hydraulic oil as a working fluid pressurized and supplied from a main pump 13 as a pump. As shown in the drawing, a differential pressure between the inlet side and the outlet side of the filter element 35 is set by a spring 38 in the bypass passage 36 that connects the inlet side and the outlet side of the filter element 35 of the return line filter 31. A bypass valve 37 is provided that opens when the pressure exceeds the relief setting pressure.In parallel with the bypass valve 37, the filter is clogged when the differential pressure between the inlet side and the outlet side of the filter element 35 exceeds the relief setting pressure. An indicator 39 is provided as a clogging sensing means for sensing clogging and transmitting a clogging sensing signal.
[0039]
Further, as shown in FIG. 3, the indicator 39 is connected to the controller 43, and when the indicator 39 detects clogging, the clogging detection signal is sent to the controller 43.
[0040]
This controller 43 has a capability reduction function that reduces the capability of the hydraulic circuit in response to a clogging detection signal from the indicator 39. For example, the controller 43 is connected to the rotational speed control unit of the engine 12 for driving the pump. The controller 43 that has received the clogging detection signal from the indicator 39 has a function of reducing the rotational speed of the engine 12.
[0041]
In addition, the controller 43 has a capability reduction function, for example, by connecting the controller 43 to an electromagnetic valve provided in a hydraulic oil passage or a pilot passage for supplying hydraulic oil to the breaker 22 or other hydraulic actuator, and an indicator The controller 43 receiving the clogging detection signal from 39 may switch the operation of the breaker 22 and the like by switching the electromagnetic valve to the throttle position.
[0042]
Further, the controller 43 has a built-in timer function that cuts a malfunction signal of the indicator 39 according to the time length of the clogging detection signal output from the indicator 39.
[0043]
This timer function outputs an output signal in response to a continuous input signal that exceeds a set fixed time, and does not output an output signal in response to an input signal that is shorter than that.
[0044]
For this reason, even if the indicator 39 malfunctions due to the hydraulic pulsation in the return passage 24 that occurs when the breaker 22 is struck, the timer function of the controller 43 detects the short-time clogging caused by the hydraulic pulsation. By cutting the signal, that is, the pulsation signal, as the malfunction signal of the indicator 39, before the indicator 39 outputs only the continuous clogging detection signal, the breaker operating force and The possibility that the operating speed, that is, the striking force and the striking speed cannot be obtained can be prevented.
[0045]
On the other hand, when the controller 43 receives a continuous clogging detection signal transmitted from the indicator 39 for a predetermined time or more, the clogging of the filter element 35 has reached its limit. The rotational speed of the engine 12 is reduced.
[0046]
As a result, the pump discharge pressure and the pump discharge flow rate are reduced, and the necessary operating force and operating speed of the breaker 22, that is, the breaker striking force and the striking speed are temporarily reduced. Informs you of an abnormality such as the need for replacement. Therefore, the operator can surely recognize the filter clogging state due to the performance degradation of the breaker 22, and can appropriately cope with the filter clogging state.
[0047]
Next, the number of clogging detection signals transmitted from the indicator 39 is counted and displayed on the display 42 in the embodiment shown in FIG. 1 or the controller 43 in the embodiment shown in FIG. counting means (not shown) embedded free.
[0048]
And, every time the bypass valve 37 is opened, the number of times the clogging detection signal transmitted from the indicator 39 is counted and displayed by the counting means, so that the number of bypasses can be counted and displayed. By monitoring the number of times of clogging detection signal transmission at bypass communication, that is, the number of bypasses, which increases as the pollution level deteriorates, it is possible to grasp the pollution level of hydraulic oil and predict the filter element replacement time. .
[0049]
Note that the output means is not limited to the clogging warning means such as the indicator 42, and includes a backwash mechanism that automatically releases the filter clogged state by the backflow of fluid.
[0050]
Furthermore, the present invention is not limited to the hydraulic circuit of the breaker, but can be applied to a fluid pressure circuit of a fluid pressure actuator of other work machines and industrial machines that are operated in an environment such as dust.
[0051]
【The invention's effect】
According to the first aspect of the invention, clogging sensing means and outputs a clogging sensing signal by sensing filter plugging state from the differential pressure between the inlet side and the outlet side of the filter, the malfunction checking means, the filter Since the malfunction detection signal of the clogging detection means due to pulsation on the inlet side is cut and the output means outputs a continuous clogging detection signal, even if pulsation occurs on the filter inlet side during operation of the fluid pressure actuator, The filter clogging condition can be detected and the filter clogging condition can be dealt with appropriately, and the number of times the clogging detection signal is sent is counted by the counting means and displayed to reduce the contamination level of the working fluid. Accordingly, the degree of contamination of the working fluid can be grasped from the number of times the clogging detection signal is increased, and the filter element replacement time can be predicted.
[0052]
According to the second aspect of the present invention, even when the clogging detecting means malfunctions due to the pulsation generated when the fluid pressure actuator is operated, the short-time clogging detection signal generated by the pulsation is detected by the simple timer. By cutting the malfunction detection signal of the clogging detection means, it is possible to easily prevent the output means from malfunctioning.
[0053]
According to the third aspect of the present invention, the clogging warning means is actuated by the clogging detection signal that has passed through the malfunction check means to warn of the filter clogging state. It is possible to replace the filter.
[0054]
According to the fourth aspect of the present invention, the controller which has received the clogging sensing signal from clogging sensing means, by reducing the ability of the fluid pressure circuit, since the required operation of the hydraulic actuator can not be obtained, From such a state, the filter clogging state can be reliably recognized, the filter clogging state can be appropriately dealt with, and the number of times the clogging detection signal is transmitted is counted by the counting means and displayed. From the number of transmissions of the clogging detection signal that increases with the deterioration of the contamination level, the contamination level of the working fluid can be grasped and the filter element replacement time can be predicted.
[0055]
According to the fifth aspect of the present invention, the controller having received the clogging detection signal from the clogging detection means decreases the rotational speed of the pump driving engine, thereby reducing the pump discharge pressure and the pump discharge flow rate. Thus, since the required operating force and operating speed of the fluid pressure actuator cannot be obtained, the filter clogging state can be reliably recognized from such a state, and the filter clogging state can be appropriately dealt with.
[0056]
According to the sixth aspect of the present invention, even when the clogging detecting means malfunctions due to the pulsation generated when the fluid pressure actuator is operated, the short-time clogging detection signal generated by the pulsation is provided by the timer function of the controller. Can be prevented as a malfunction signal of the clogging sensing means, so that the controller affected by the pulsation can be prevented from degrading the capacity of the fluid pressure circuit.
[0057]
According to the seventh aspect of the present invention, when the differential pressure between the inlet side and the outlet side of the filter element becomes equal to or higher than the relief set pressure of the bypass valve, the bypass valve opens and the bypass passage allows the inlet side and outlet of the filter element to be opened. Since the filter element can be prevented from being damaged due to excessive differential pressure, a clogging detection signal is sent from the indicator each time the bypass valve is opened. Ru can be confirmed from the outside.
[Brief description of the drawings]
FIG. 1 is a circuit diagram of a fluid pressure circuit including an embodiment of a fluid cleaning apparatus according to the present invention.
FIG. 2 is a circuit diagram showing a filter, a bypass valve, and an indicator in the fluid purification device same as above.
FIG. 3 is a circuit diagram of a fluid pressure circuit including another embodiment of the fluid purification apparatus according to the present invention.
FIG. 4 is a circuit diagram of a fluid pressure circuit including a conventional fluid cleaning device.
[Explanation of symbols]
12 engine
13 Main pump as pump
22 Breaker as a fluid pressure actuator
24 Return passage
31 Return line filter as a filter
35 Filter elements
36 Bypass passage
37 Bypass valve
39 Indicators for clogging detection
41 Timer as a check for malfunction
42 Indicator as output means (as clogging warning means)
43 Controller

Claims (7)

A filter provided in the return path from the fluid pressure actuator;
A clogging sensing means for sensing a clogged filter state from a differential pressure between the inlet side and the outlet side of the filter and outputting a clogging detection signal;
Malfunction check means for cutting malfunction signal of clogging sensing means due to pulsation on the inlet side from the filter;
Outputs a continuous clogging detection signal that exceeds the set fixed time through the malfunction check means, and also increases the clogging detection signal that increases as the contamination level of the working fluid transmitted from the clogging detection means deteriorates . number fluid purification apparatus to that fluid pressure circuit, characterized by comprising an output means having a counting means for counting and displaying the. The malfunction check means is
It is a timer that checks the malfunction of the clogging detection means based on the time length of the clogging detection signal output from the clogging detection means, and cuts the pulsation signal shorter than the set fixed time. The fluid cleaning device for a fluid pressure circuit according to claim 1. The output means is
The fluid cleaning device for a fluid pressure circuit according to claim 1 or 2, wherein the fluid pressure circuit is a clogging warning unit that operates in response to a clogging detection signal that has passed through a malfunction check unit and warns of a filter clogging state. A filter provided in a return passage from a fluid pressure actuator operated by a working fluid pressurized and supplied from a pump;
A clogging sensing means for sensing a clogged filter state from a differential pressure between the inlet side and the outlet side of the filter and outputting a clogging detection signal;
Contamination of the working fluid transmitted from the clogging sensing means as well as having a capability lowering function that reduces the ability of the fluid pressure circuit to limit the operation of the fluid pressure actuator in response to the clogging sensing signal from the clogging sensing means fluid purification apparatus that fluid pressure circuit to and characterized by including a controller having a counting means for displaying a count of the number of times of clogging sensing signal increases with the deterioration of the degree situation. The controller
The fluid cleaning device for a fluid pressure circuit according to claim 4, further comprising a function of receiving a clogging sensing signal from the clogging sensing means and reducing a rotational speed of an engine for driving the pump. The controller
A timer function is provided that cuts the malfunction signal from the clogging detection means according to the time length of the clogging detection signal output from the clogging detection means, and cuts the pulsation signal shorter than the set fixed time . 6. The fluid cleaning device for a fluid pressure circuit according to claim 4, The filter
A replaceable filter element;
A bypass passage communicating the inlet side and the outlet side of the filter element;
A bypass valve provided in the bypass passage and opened when the differential pressure between the inlet side and the outlet side of the filter element is equal to or higher than the relief set pressure;
The fluid pressure circuit according to any one of claims 1 to 6, further comprising an indicator for transmitting a clogging detection signal when a differential pressure between the inlet side and the outlet side of the filter element is equal to or higher than a relief set pressure. Fluid cleaning equipment.

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