JPH10299721A - Life detection device for operating oil in hydraulic circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To always detect the life of an operating oil stably and accurately by detecting the information about the life from the operating oil in a stably pressurized state. SOLUTION: This hydraulic circuit 2 has an operating oil tank 11 for storing operating oil in which a desired additive is added in a base oil component appraised by an acid value and base value and unmelted foreign article is contained and a hydraulic pump 12 for delivering and supplying the operating oil in this operating oil tank 11 as a prescribed pressed oil. This device is provided with sensors (group) 17 for detecting the information about the life of the operating oil and an operating oil life detection means 19 for detecting the life of the operating oil based on the detection result by this sensor 17 and the sensor 17 is arranged to the low pressure oil passage part 15B in the hydraulic circuit 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic oil life detecting device for a hydraulic circuit, and more particularly to a hydraulic oil suitable for detecting the life of hydraulic oil used in a hydraulic circuit of a construction machine such as a hydraulic shovel. The present invention relates to a device for detecting the operating oil life of a circuit.

[0002]

2. Description of the Related Art FIG. 5 shows an example of a hydraulic shovel as a general construction machine. As shown in FIG. 5, a hydraulic shovel is usually mounted on a lower traveling body 500 having an infinite rail section 500A. An upper revolving unit 100 with a driving room (cabin) 600 is provided, and the upper revolving unit 100 is further provided with an articulated arm mechanism including a boom 200, a stick 300, and a bucket 400.

[0003] The hydraulic excavator has a boom 2
00, a hydraulic cylinder 121 for the stick 300, and a hydraulic cylinder 122 for the bucket 400.
A hydraulic circuit (not shown) for each of the hydraulic cylinders 120 to 122 is provided, and a control valve in the hydraulic circuit is electronically controlled according to an operation of an operator to supply hydraulic fluid to the hydraulic cylinders 120 to 122. The boom 200, the stick 300, and the bucket 400 are driven by changing the supply amount (oil pressure) of the hydraulic cylinders 120 to 122 as appropriate.

[0004] By the way, as is well known, the quality of the hydraulic oil in the above-mentioned hydraulic circuit deteriorates as its use is continued, so that it is necessary to replace the hydraulic oil at regular intervals. For this reason, in recent years, it has been desired to be able to accurately detect the service life of hydraulic oil in a hydraulic circuit. Therefore, conventionally, for example, it has been considered that the life of the hydraulic oil can be detected by providing a sensor for detecting the degree of deterioration of the base oil component in a hydraulic oil tank for storing the hydraulic oil.

[0005]

However, usually,
Since the high-pressure hydraulic fluid discharged from the hydraulic pump flows back into the hydraulic circuit and flows into the hydraulic oil tank, even if a sensor is provided in the hydraulic oil tank as described above, the pressure of the hydraulic oil in the tank may be reduced. Since the state is not stable, it is very difficult to accurately detect the degree of deterioration of the base oil component to detect the life of the hydraulic oil.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and detects information on the service life of a hydraulic oil whose pressure is stable, so that the life of the hydraulic oil can be constantly and accurately determined. It is an object of the present invention to provide a hydraulic oil life detecting device for a hydraulic circuit, which is capable of detecting a hydraulic fluid.

[0007]

SUMMARY OF THE INVENTION For this reason, a hydraulic oil life detecting device for a hydraulic circuit according to the present invention comprises a base oil component which can be evaluated based on an acid value and a base value, to which a required additive is added and an insoluble foreign substance is removed. In a hydraulic circuit having a hydraulic oil tank for storing hydraulic oil which may be contained, and a hydraulic pump for discharging and supplying the hydraulic oil in the hydraulic oil tank as a predetermined pressure oil, a sensor for detecting information regarding the life of the hydraulic oil, A hydraulic oil life detecting means for detecting the life of the hydraulic oil based on the detection result of the sensor is provided, and the sensor is disposed in a low-pressure oil passage in the hydraulic circuit.

With the above-described structure, in the hydraulic oil life detecting device of the present invention, information on the life of the hydraulic oil in the low-pressure oil passage is detected by the sensor, and based on the detection result, Since the life of the hydraulic oil is detected, the life of the hydraulic oil in the hydraulic circuit can be detected stably and reliably (claim 1). Here, if the low-pressure oil passage portion in the above-mentioned hydraulic circuit is a suction flow path from the above-mentioned hydraulic oil tank to the hydraulic pump, the above-mentioned sensor detects the hydraulic oil passing through the suction flow path, that is, once the hydraulic oil By storing the oil in the tank, the oil pressure thereof is lowered, and information on the life of the working oil in a stable pressure state can be detected (claim 2).

[0009] Further, the above-mentioned sensor includes a first sensor for detecting an additive in the hydraulic oil, a second sensor for detecting an acid value and a base value of a base oil component in the hydraulic oil, and an insoluble material in the hydraulic oil. If a first sensor, a second sensor, and a third sensor are provided in the low-pressure oil passage portion, the first to third sensors can be provided.
By the third sensor, as information on the life of the hydraulic oil,
Stable detection of multiple information that changes according to the life of the hydraulic oil, such as the additive value in the hydraulic oil, the acid value and base value of the base oil component in the hydraulic oil, and the insoluble foreign matter in the hydraulic oil Therefore, the operating oil life detecting means can reliably detect the operating oil life based on the plurality of pieces of information.

If the first sensor, the second sensor, and the third sensor are arranged in tandem in the low-pressure oil passage, the above-mentioned information (for the hydraulic oil passing through the low-pressure oil passage) is provided. Information about the life of the hydraulic oil)
This information can be detected under the same conditions as other sensors (claim 4).

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram schematically showing a hydraulic excavator equipped with a hydraulic oil life detecting device for a hydraulic circuit as one embodiment of the present invention. As shown in FIG. Infinite rail section 5
00A, the driving operation room 60
The upper revolving superstructure with zero (construction machine main body) 100 is rotatably provided in a horizontal plane.

Then, with respect to the upper swing body 100,
Boom (arm member) 20 whose one end is rotatably connected
0, and a stick (arm member) 300 whose one end is rotatably connected to the boom 200 via a joint. In addition, stick 30
A bucket (working member) 400 having one end rotatably connected to the base through an articulation portion and excavating the ground at its tip and capable of storing earth and sand therein is provided. FIG.
, The tip of the bucket 400 is indicated by reference numeral 112.

Thus, the boom 200 and the stick 3
The bucket 400 has one end pivotally connected to the upper revolving unit 100 and has the bucket 400 on the other end, and at least the boom 200 and the stick 300 as a pair of arm members connected to each other via a joint. Having an articulated arm mechanism. Also, a boom hydraulic cylinder 120, a stick hydraulic cylinder 121, and a bucket hydraulic cylinder 122 (hereinafter referred to as a boom hydraulic cylinder 120)
Are sometimes referred to as boom cylinder 120 or simply cylinder 120, stick hydraulic cylinder 121 is sometimes referred to as stick cylinder 121 or simply cylinder 121, and bucket hydraulic cylinder 122 is sometimes referred to as bucket cylinder 122 or simply cylinder 122). ing.

Here, one end of the boom cylinder 120 is rotatably connected to the upper swing body 100, and the other end is rotatably connected to the boom 200, ie, the upper swing body 100 The boom 200 is interposed between the boom 200 and the boom 200 by extending and contracting the distance between the ends.
00 can be rotated with respect to the upper swing body 100.

The stick cylinder 121 has one end rotatably connected to the boom 200 and the other end rotatably connected to the stick 300. That is, the stick cylinder 121 is connected between the boom 200 and the stick 300. The stick 300 can be rotated with respect to the boom 200 by being interposed therebetween and by expanding and contracting the distance between the ends.

Further, the bucket cylinder 122 has one end rotatably connected to the stick 300 and the other end rotatably connected to the bucket 400, that is, the connection between the stick 300 and the bucket 400. The bucket 400 can be rotated with respect to the stick 300 by being interposed between the sticks 300 as the distance between the ends expands and contracts. The bucket hydraulic cylinder 1
A link mechanism 130 is provided at the distal end of 22.

Although not shown, the left and right endless rail portions 5 are provided.
00A and the upper revolving unit 1
A turning motor for turning 00 is also provided. As shown in FIG. 2, the above-described hydraulic shovel includes at least the cylinders 120 to 122 and the above-described turning motor 1.
The hydraulic circuit 2 is provided with a hydraulic pump 1 driven by a hydraulic oil tank 11 and an engine (diesel engine) E.
2, control valve (3-way switching valve) 13A-1
3D and the like are interposed.

Here, the hydraulic oil tank 11 stores hydraulic oil, and the hydraulic pump 12 discharges and supplies the hydraulic oil in the hydraulic oil tank 11 as a predetermined pressure oil. It is configured as a piston type variable displacement pump, and the flow rate of hydraulic oil can be controlled by changing the stroke amount of a piston (not shown) provided in the pump 12. That is, one end of the piston is configured to abut on a swash plate (creep plate: not shown), and by changing the inclination (tilt angle) of the swash plate, the stroke amount of the piston is changed and the pump 12 The discharge amount is changed.

The control valves 13A to 13D
Are used to control the expansion and contraction of the cylinders 120 to 122 and the rotation direction of the rotation motor 123 by switching the supply direction of the hydraulic oil to the cylinders 120 to 122 and the rotation motor 123. When switching is performed in the direction of arrow B shown in FIG.
With respect to the above, while the hydraulic oil is supplied to the inner chamber 124 and the hydraulic oil is drawn out from the inner chamber 125 and the cylinder 120 is extended, when switching is performed in the direction of arrow A, the hydraulic oil is supplied to the inner chamber 125 and Hydraulic oil is extracted from the cylinder 124 so that the cylinder 120 contracts, and the rotation direction of the swing motor 123 is reversed in accordance with the switching between the directions of the arrows A and B.

Each of these control valves 13
The switching control of A to 13D is performed by the upper revolving superstructure 1
The operation is performed by the controller 1 provided in the operation room 60.
A switching control signal for the control valves 13A to 13D is generated based on operation information obtained by operating the boom / bucket operation lever 6 and the stick / slewing operation lever 8 within 0, and each control valve 1
A switching control signal is supplied to each of 3A to 13D.

Further, as shown in FIG. 2, the hydraulic circuit 2 is provided with a relief valve 14 on the discharge port side of the hydraulic pump 12, which can communicate with a return line 15A to the hydraulic oil tank 11. When the discharge pressure of the pump 12 becomes higher than a predetermined pressure, the relief valve 20 is opened, and the hydraulic oil pressurized by the pump 12 is returned to the tank 11.

Usually, the above-mentioned hydraulic oil is obtained by adding a polymer additive such as an antioxidant, an anti-wear agent and a rust preventive to a base oil component. As the use continues, its quality naturally deteriorates. For this reason, when the quality of the above-mentioned hydraulic oil deteriorates to a certain extent (it becomes the end of its life), it is necessary to replace it with new one.

The replacement time (life of the hydraulic oil) depends on the acid value and base value of the base oil component and the amount (proportion) of the additive in the hydraulic oil, as well as the cylinders 120 to 122, the swing motor 123, and the hydraulic pressure. Judgment is made by observing the amount of insoluble foreign matter such as metal powder that can be contained in the hydraulic oil due to internal friction of the movable part in the hydraulic circuit 2 such as the pump 12 and moisture that can enter from the outside through the rod seal portions of the cylinders 120 to 122. can do.

That is, when the quality of the hydraulic oil is deteriorated, the acid value and the base value of the base oil component and the amount of the insoluble foreign matter tend to increase, while the amount of the additive tends to decrease. Therefore, in the present embodiment, as shown in FIGS. 1 and 2, in order to detect the life of the hydraulic oil by looking at all the information on the life of the hydraulic oil (hereinafter referred to as life information),
A hydraulic oil life detecting device 16 is provided in the hydraulic circuit 2 described above.

As shown in FIG. 2, a hydraulic oil life detecting device (hereinafter, may be simply referred to as a “detecting device”) 16 of the present embodiment includes a sensor group 17 and an A / D (analog / analog).
It comprises a (digital) converter 18, a hydraulic oil deterioration degree discriminating circuit 19, and a hydraulic oil life indicator 20.
Here, the sensor group (detection means) 17 uses the additives (oxidizing agent, anti-wear agent,
Rust inhibitor), base oil component (acid value, base value), and insoluble foreign matter (metal powder, moisture), respectively.
17G.

An antioxidant sensor 17A for detecting an acid-resistant agent in the hydraulic oil An anti-wear agent sensor 17B for detecting an anti-wear agent in the hydraulic oil A anti-rust sensor 17C for detecting a rust inhibitor in the hydraulic oil Total acid value sensor 17D for detecting total acid value of base oil component in hydraulic oil Total base number sensor 17E for detecting total base value of base oil component in hydraulic oil Detects insoluble foreign matter (metal powder) in hydraulic oil Metal powder sensor 17F Moisture sensor 17G detecting insoluble foreign matter (moisture) in hydraulic oil That is, the above-described sensor group 17 is an additive sensor (first sensor) that detects an additive in hydraulic oil. Sensors 17D, 17D, and 17C, which have the sensors 17A to 17C shown in FIG.
17E, and sensors 17F and 17G described above as insoluble foreign matter sensors (third sensors) for detecting insoluble foreign matter in the hydraulic oil.

Thus, the sensor group 17 determines whether the additives (oxidizing agent, anti-wear agent, rust inhibitor) in the hydraulic oil, the acid value and the base value of the base oil component, and the life of the hydraulic oil such as insoluble foreign matter. It is possible to precisely and reliably detect an element whose amount or value changes according to the information as the life information.
In the present embodiment, each of the sensors 17A to 17G is arranged in a cascade on a suction flow path (pump suction line) 15B from the hydraulic oil tank 11 which is a low-pressure oil path to the hydraulic pump 12. Accordingly, each of the sensors 17A to 17G is connected to the hydraulic oil passing through the pump suction line 15B, that is, the hydraulic oil tank 11 once.
The hydraulic pressure is reduced by being stored in the hydraulic fluid, and the hydraulic fluid is stabilized under the same detection conditions as the other sensors other than its own (for the hydraulic fluid passing through the same pump suction line 15B). ), It is possible to perform the above detection (sensing) processing.

In FIG. 2, the A / D converter 18
A / D-converts the hydraulic oil life information (analog signal) detected by the corresponding sensors 17A to 17G into a digital signal. The hydraulic oil deterioration degree determination circuit (hydraulic oil life detecting means) 19 Are the respective sensors 17A to 17 which have been A / D converted in the respective A / D converters 18.
The sensor detects the life of the hydraulic oil based on the detection result at G (the information on the life of the hydraulic oil).
The life of the hydraulic oil is evaluated for each detection result at 17G, and whether or not the hydraulic oil has reached the end of life is detected by comprehensively judging each evaluation result.

For this reason, specifically, as shown in FIG. 3, for example, the hydraulic oil deterioration degree determination circuit 19 includes a threshold value setting section 191A to 191G, a comparison section 192A to 192G, and an OR circuit (logical sum circuit) 193. Is configured. Here, the threshold value setting unit 191A sets a threshold value for the amount of the additive (oxidizing agent) in the hydraulic oil, and the threshold value setting unit 191B sets the additive (anti-wear agent) in the hydraulic oil. A threshold for the amount of the agent)
The threshold value setting section 191C sets a threshold value for the amount of the additive (rust inhibitor) in the hydraulic oil.

The threshold value setting section 191D sets a threshold value for the total acid value of the base oil component in the hydraulic oil, and the threshold value setting section 191E sets the threshold value for the total base value of the base oil component in the hydraulic oil. The threshold value setting unit 191F sets a threshold value for the amount of metal powder in the hydraulic oil, and the threshold value setting unit 191G sets a threshold value for the water content in the hydraulic oil. Is set in advance.

Further, the comparison sections 192A to 192C compare the detection results of the corresponding additive sensors 17A to 17C with the thresholds set in the corresponding threshold setting sections 191A to 191C, respectively. When any of the detection results of the additive sensors 17A to 17C is below the threshold (that is, the amount of the additive in the hydraulic oil is below the threshold),
Assuming that the hydraulic oil has reached the end of its life, the evaluation result (H
Pulse).

The comparison units 192D and 192E compare the detection results of the corresponding acid value / base value sensors 17D and 17D with the threshold values set in the corresponding threshold value setting units 191D and 191E, respectively. Here, sensor 1
When the detection results at 7D and 17E exceed the threshold value (that is, the acid value and base value of the base oil component in the hydraulic oil exceed the threshold value), the hydraulic oil has reached the end of its life and the evaluation result (H pulse ).

Further, the comparison sections 192F and 192G compare the detection results of the corresponding insoluble foreign matter sensors 17F and 17G with the thresholds set in the corresponding threshold setting sections 191F and 191G, respectively. , Sensor 1
If the detection results at 7F and 17G exceed the threshold value (that is, the amount of insoluble foreign matter (metal powder, moisture) in the hydraulic oil exceeds the threshold value), the hydraulic oil has reached the end of its life and the evaluation result (H pulse).

That is, the comparison units 192A to 192C
Is a first comparison unit that compares the detection results of the additive sensors 17A to 17C with the thresholds (first thresholds) of the threshold setting units 191A to 191C and outputs a first evaluation result of the life of the hydraulic oil. Of the comparison unit 1 described above.
92D and 192E are acid value / base value sensors 17D and 17
E and the threshold value (second threshold value) of the threshold value setting units 191D and 191E are compared with each other to determine the second life of the hydraulic oil.
The comparison units 192F and 192G perform the function of outputting the evaluation results of the above. The comparison units 192F and 192G output the detection results of the insoluble foreign matter sensors 17F and 17G and the threshold values of the threshold setting units 192F and 192G. (Three thresholds) to output a third evaluation result of the service life of the hydraulic oil.
It functions as a comparison unit.

Note that the above threshold setting units 191A to 191
Each threshold value of G (first threshold value, second threshold value, and third threshold value) can be set as a changeable value that can be changed from the outside. For example, when the type of the operating oil to be changed is changed, the life determination condition of the operating oil can be adjusted or changed.

The above-mentioned OR circuit (judgment unit) 193
Calculates the logical sum of the outputs of the comparison units 192A to 192G so that the comparison units 192A to 192G (first
When an H pulse is output from any of the comparison unit, the second comparison unit, and the third comparison unit), it is determined that the operating oil has reached the end of its life and an H pulse is output. That is, the above-described hydraulic oil deterioration degree determination circuit 19 includes the additive sensors 17A to 17C,
If any one of the evaluation results of the life of the hydraulic oil based on the detection results of the acid value / base value sensors 17D and 17E and the insoluble foreign matter sensors 17F and 17G indicates that the hydraulic oil has reached the end of its life, the hydraulic oil It is determined that the life has expired.

Further, in FIG. 2, a hydraulic oil life display means 20 displays the life of the hydraulic oil in accordance with the result of detection (determination) by the above-mentioned hydraulic oil deterioration degree determination circuit 19, and the present embodiment. Here, the monitor 10 provided in the driving operation room 600 also has this function. That is, as shown in FIG. 4, for example, the monitor 10 has an engine cooling water temperature display unit 101, a fuel display unit 102, a character display 103, a hydraulic oil temperature display unit 104, and various alarm indicators 105 to 10 on a monitor panel 10A.
9 and a hydraulic oil life warning indicator 110 as the hydraulic oil life display means 20 is arranged. If the determination circuit 19 determines that the hydraulic oil has reached the end of its life, The indicator 110 is turned on or blinks to notify the operator that the operating oil has reached the end of its life.

The alarm indicator 105 indicates that the remaining amount of the battery is low, the alarm indicator 106 indicates that the temperature of the engine cooling water is higher than a predetermined temperature, and the alarm indicator 107 indicates that the temperature of the hydraulic oil is low. When the temperature becomes higher than the predetermined temperature, the alarm indicator 10
Reference numeral 8 indicates that when the pressure of the engine oil becomes higher than a predetermined value and the alarm indicator 109 lights up or blinks when an abnormality occurs in the controller 1, the abnormality is notified to the operator. I have.

The operation of the hydraulic oil life detecting device 16 of the hydraulic circuit 2 according to the present embodiment configured as described above will be described below. First, the detection device 16 uses the sensors 17A to 17G constituting the sensor group 17 to add additives (antioxidant, antiwear agent, antirust agent) to the hydraulic oil passing through the pump suction line 15B. , Acid value and base value of base oil component, and various life information of insoluble foreign matter are detected.

At this time, each of the sensors 17A to 17G converts the hydraulic oil passing through the pump suction line 15B, that is, the hydraulic oil, which is temporarily stored in the hydraulic oil tank 11 to lower its oil pressure, to a stable hydraulic oil. On the other hand, since the above-described detection processing is performed, various kinds of life information can always be obtained stably. In addition, each of the sensors 17A to 17A
7G are arranged in tandem on the pump suction line 15B, so that the above-described detection processing is performed on the hydraulic oil passing through the same pump suction line 15B, respectively, so that other sensors other than the own one can be used. Various life information can be obtained under the same detection conditions.

Then, as described above, each of the sensors 17A to 17A
The life information obtained in 7G is the corresponding A / D
After the A / D conversion is performed by the converter 18, the output is output to the hydraulic oil deterioration degree determination circuit 19. In the hydraulic oil deterioration degree discriminating circuit 19, each of the sensors 1 that have been A / D converted by each A / D converter 18
The life of the hydraulic oil is evaluated for each of the detection results (life information) in 7A to 17G, and the evaluation result is comprehensively determined to determine whether the hydraulic oil has reached the life.

That is, the detection results (life information) of the respective sensors 17A to 17G and the respective thresholds of the respective threshold setting units 191A to 191G are compared by the corresponding comparators 192A to 192G, respectively. If the amount of any one (or a plurality) of the agent, the antiwear agent, and the rust inhibitor is below the threshold value, the corresponding comparators 192A to 192C output the H pulse as the evaluation result.

Similarly, if either (or both) the acid value or the base value of the base oil component in the hydraulic oil exceeds the threshold value, the corresponding comparators 192D and 192E output an H pulse as an evaluation result, and If the amount of any (or both) of insoluble foreign matter (metal or moisture) in the oil exceeds the threshold value, the corresponding comparison unit 192F or 19
An H pulse is output as an evaluation result from 2G.

As a result, the comparison units 192A to 192
When at least one of the outputs of G becomes H level, the OR circuit 193
Is at the H level, the hydraulic oil life warning indicator 110 on the monitor panel 10A turns on or flashes to notify the operator that the hydraulic oil has reached the end of its life. Thereby, the operator can accurately recognize the timing of replacing the hydraulic oil, and it is possible to extremely effectively prevent the adverse effect on the hydraulic shovel due to the continuous use of the deteriorated hydraulic oil.

As described above, according to the hydraulic oil life detecting device 16 of the hydraulic circuit 2 in the present embodiment, the addition of the stable hydraulic oil from the hydraulic oil passing through the pump suction line 15B, which is the low-pressure oil passage portion, to the hydraulic oil is added. Agents (antioxidants, antiwear agents, rust inhibitors), acid value and base value of base oil components,
Since a plurality of pieces of hydraulic oil life information of undissolved foreign substances are finely detected and the life of the hydraulic oil is detected (determined) based on the detection result, the life of the hydraulic oil is always stabilized, and
It can be detected with high accuracy (dense).

In this embodiment, each of the sensors 17A to 17A
17G are arranged in tandem on the pump suction line 15B.
G can perform the above detection processing on the hydraulic oil passing through the same pump suction line 15B. Therefore, each of the sensors 17A to 17G can obtain the above-mentioned life information under the same detection conditions as those of the other sensors other than its own, and the reliability and accuracy of the life oil life detection result are greatly improved.

Further, in the above embodiment, the threshold setting units 191A to 191G and the comparison unit 192 of the discrimination circuit 19 are used.
A to 192G evaluate the life of the hydraulic oil for each detection result of each of the sensors 17A to 17G, and the OR circuit 193 comprehensively determines each evaluation result to determine whether the hydraulic oil has reached the life. Since the detection is performed, the life of the hydraulic oil can be detected extremely accurately, and the reliability of the detection result is greatly improved.

At this time, in the discriminating circuit 19, the additive sensors 17A to 17C, the acid value / base value sensors 17D, 17E
If any one of the evaluation results of the life of the hydraulic oil based on the detection results of the insoluble foreign matter sensors 17F and 17G indicates that the hydraulic oil has reached the end of its life, it is determined that the hydraulic oil has reached its end of life. At this stage, it is possible to detect that the operating oil has reached the end of its life, and the sensitivity of detecting the life of the hydraulic oil has been greatly improved.

Further, each of the above thresholds can be set as a value which can be changed externally by an operator when the type of hydraulic oil to be used is changed or the like. The conditions can be adjusted or changed, which greatly contributes to the flexibility and versatility of the detection device 16. In the above-described embodiment, three types of information (an acid value, a base value, and a base oil component of the base oil component in the hydraulic oil) are roughly classified by the sensor group 17 (sensors 17A to 17G) as the life information of the hydraulic oil. Additives and insoluble foreign substances in hydraulic oil) are all detected in detail, but only one of them (for example, additives in hydraulic oil) or only two types is detected. In this case, the same operation and effect as described above can be obtained with a simpler configuration.

Further, in the above-described embodiment, the polymer additives such as the antioxidant, the antiwear agent and the rust preventive have been described as examples of the additives to be added to the hydraulic oil. Even when another additive is added, the same operation and effect as described above can be obtained by providing a sensor for detecting the additive as the sensor group 17. Further, in the above-described embodiment, metal powder and water have been described as examples of the insoluble foreign matter in the hydraulic oil to be detected. However, other insoluble foreign matter may be detected.

Further, in the above-described embodiment, each of the sensors 17A to 17G is connected to the pump suction line 15
B, but the present invention is not limited to this, and may be arranged in another arrangement, or may be arranged in a low-pressure oil passage other than the pump suction line 15B. Good. Further, in the above-described embodiment, if any one of the life evaluation results of the three types of life information indicates that the hydraulic oil has reached the end of its life, the determination circuit 19 determines that the hydraulic oil has reached the end of its life. However, the life of the hydraulic oil may be determined as follows.

(1) A majority decision is made for each life evaluation result, and if more than half of the total life evaluation results indicate that the hydraulic oil has reached the end of its life, it is determined that the hydraulic oil has reached its end of life. (2) Each life evaluation result is weighted, and when the evaluation result with the larger weight indicates that the operating oil has reached the life,
It is determined that the operating oil has reached the end of its life.

In the above-described embodiment, the life of the hydraulic oil is determined by comprehensively determining the three types of life evaluation results. For example, by outputting each life evaluation result as it is, The life of each component in the hydraulic oil may be determined. For example, the hydraulic oil includes a polymer additive (called a stick-slip inhibitor) for preventing abnormal noise from being generated at the seal lip portions of the cylinders 120 to 122 when the cylinders 120 to 122 operate.
In some cases, this additive is deteriorated by shearing of the polymer in a shorter time than the base oil component. In such a case, if the life of the additive is determined from the life evaluation result of the additive and only the additive whose life has expired is newly added to the hydraulic oil, it is not necessary to replace all the hydraulic oil, and the hydraulic oil is not required. This greatly contributes to the reduction of the replacement cost.

Further, in the above embodiment, the life of the hydraulic oil is displayed by lighting (or blinking) of the hydraulic oil life warning indicator 110 on the monitor panel 10A, but the engine cooling water temperature shown in FIG. Like the meter 101 and the fuel meter 102, the display can be performed stepwise, and various other display modes can be applied.

In the above embodiment, the engine E
However, the case of a diesel engine has been described, for example, but the present invention is not limited to a diesel engine or the like, as long as it is a prime mover (various internal combustion engines and the like) that can drive the hydraulic pump 12. Further, in the above-described embodiment, the case where the present invention is applied to a hydraulic excavator is described. However, the present invention is not limited to this, and at least hydraulic equipment including construction machines such as tractors, loaders, and bulldozers is used. As long as the circuit 2 (hydraulic oil) is used, the same operation and effect can be obtained in any case.

The present invention is not limited to the above-described embodiment, and can be implemented in various modifications without departing from the spirit and scope of the present invention.

[0057]

As described above in detail, according to the hydraulic oil life detecting device for a hydraulic circuit of the present invention, information on the life of the hydraulic oil in the low-pressure oil passage portion of the hydraulic circuit is detected from a stable hydraulic oil. Since the life of the hydraulic oil is detected based on the detection result, the life of the hydraulic oil in the hydraulic circuit can be detected stably and reliably, whereby the life of the hydraulic oil can always be detected stably. (Claim 1).

Here, if the low-pressure oil passage portion is a suction flow passage from the hydraulic oil tank to the hydraulic pump, the hydraulic oil passing through the suction flow passage, that is, is temporarily stored in the hydraulic oil tank. Since the information on the life of the hydraulic oil can be detected from the hydraulic oil whose hydraulic pressure is lowered and the pressure is stable, the life of the hydraulic oil can be detected extremely stably and reliably (claim 2).

Further, as information on the service life of the hydraulic oil, the additives in the hydraulic oil, the acid value of the base oil component,
If a plurality of information (life information) whose amount and value change according to the life of the hydraulic oil such as a base number and an insoluble foreign matter are detected from the hydraulic oil passing through the low-pressure oil passage portion, the plurality of information can be detected. Since the life information can be detected stably and the life of the hydraulic oil can be detected based on the plurality of life information, the life of the hydraulic oil can be detected with extremely high accuracy. 3).

The above life information is obtained by sensors arranged in tandem in the low pressure oil passage, respectively.
By detecting from the hydraulic oil passing through the low pressure oil passage,
Since these life information can be detected under the same conditions as other sensors, the reliability of the hydraulic oil life detection results,
Accuracy can be greatly improved (claim 4).

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing a hydraulic shovel equipped with a hydraulic oil life detecting device for a hydraulic circuit as one embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration of a main part of a hydraulic circuit applied to the hydraulic shovel according to the embodiment;

FIG. 3 is a block diagram illustrating a configuration of a hydraulic oil deterioration degree determination circuit in the hydraulic oil life detection device for a hydraulic circuit according to the present embodiment.

FIG. 4 is a block diagram illustrating an example of a monitor used in the excavator according to the embodiment.

FIG. 5 is a diagram illustrating an example of a hydraulic shovel as a general construction machine.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Controller 2 Hydraulic circuit 6 Boom / bucket operation lever 8 Stick / Swivel operation lever 10 Monitor 10A Monitor panel 11 Hydraulic oil tank 12 Hydraulic pump 13A-13D Control valve (3-way switching valve) 14 Relief valve 15A Return line 15B Pump suction line (Suction passage, low-pressure oil passage) 16 Hydraulic oil life detecting device 17 Sensor group (detecting means) 17A Antioxidant sensor (additive sensor, first sensor) 17B Antiwear agent sensor (additive sensor, first sensor) Sensor) 17C Rust inhibitor sensor (additive sensor, first sensor) 17D Total acid value sensor (acid value / base value sensor, second sensor) 17E Total base value sensor (acid value / base value sensor, second sensor) 17F Metal powder sensor (insoluble foreign matter sensor, 3rd sensor) 17G Moisture sensor (Insoluble foreign matter sensor, third sensor) 18 A / D (analog / digital) converter 19 Hydraulic oil deterioration degree discrimination circuit (hydraulic oil life detecting means) 20 Hydraulic oil life display means 100 Upper revolving body (construction machine body) 101 Engine Cooling Water Temperature Display Unit 102 Fuel Display Unit 103 Character Display 104 Hydraulic Oil Temperature Display Unit 105-109 Alarm Indicator 110 Hydraulic Oil Life Warning Indicator 112 Tooth Tip 120 Boom Hydraulic Cylinder 121 Stick Hydraulic Cylinder 122 Bucket Hydraulic Cylinder 123 Swing Motor 124, 125 Inner room 130 Link mechanism 191A-191G Threshold setting section 192A-192C Comparison section (first comparison section) 192D, 192E Comparison section (second comparison section) 192F, 192G Comparison section (third comparison section) 193 OR circuit (logic) Sum circuit: Tough) 200 boom 300 stick 400 bucket 500 undercarriage 500A caterpillar unit 600 operator cab E engine (diesel engine)

Claims (4)

[Claims] 1. A hydraulic oil tank for storing a hydraulic oil in which a required additive is added to a base oil component which can be evaluated based on an acid value and a base value and which may contain an insoluble foreign matter, and a hydraulic oil tank in the hydraulic oil tank. In a hydraulic circuit having a hydraulic pump that discharges and supplies hydraulic oil as a predetermined pressure oil, a sensor that detects information on the life of the hydraulic oil, and detects a life of the hydraulic oil based on a detection result of the sensor A hydraulic oil life detecting device for a hydraulic circuit, comprising a hydraulic oil life detecting means, wherein the sensor is disposed in a low-pressure oil passage portion of the hydraulic circuit. 2. A hydraulic oil life detecting device for a hydraulic circuit according to claim 1, wherein the low-pressure oil path portion in the hydraulic circuit is a suction flow path from the hydraulic oil tank to a hydraulic pump. . 3. The sensor according to claim 1, wherein the sensor detects an additive in the hydraulic oil, a second sensor detects an acid value and a base value of a base oil component in the hydraulic oil, A third sensor for detecting undissolved foreign matter, wherein the first sensor, the second sensor, and the third sensor are all disposed in the low-pressure oil passage portion;
The hydraulic oil life detecting device for a hydraulic circuit according to claim 1. 4. The first sensor, the second sensor and the third sensor.
The hydraulic oil life detecting device for a hydraulic circuit according to claim 3, wherein sensors are arranged in tandem with the low-pressure oil passage portion.