JP6828561B2 - Impurity detector in hydraulic fluid of hydraulic equipment - Google Patents

Description

The present invention relates to a device for detecting impurities such as metal wear powder mixed in hydraulic oil of a flood control device.

Regarding this kind of technology, for example, there is one described in Patent Document 1. The hydraulic oil contamination state diagnostic device described in Patent Document 1 includes a microcell made of a transparent glass material having a hydraulic oil flow path formed inside, an optical sensor embedded in the microcell, and an upstream of the microcell. It is equipped with a mini pump attached to the end via a connector. The microcell with the optical sensor and minipump is installed in the middle of the sampling tube for collecting hydraulic oil. One end of the sampling pipe is connected to the bottom side of the hydraulic oil tank, and the other end of the sampling pipe is connected to the hydraulic oil return pipe. The hydraulic oil in the hydraulic oil tank sucked by the mini pump flows through the flow path formed inside the microcell. Impurities mixed in the hydraulic oil are detected by an optical sensor.

With the above-mentioned hydraulic oil contamination state diagnostic device, impurities such as metal wear debris and sand mixed in the hydraulic oil of the hydraulic drive circuit used for hydraulic excavators can be continuously detected in-line, and the hydraulic oil is contaminated. It is described in Patent Document 1 that the condition can be stably diagnosed.

Japanese Unexamined Patent Publication No. 2001-221793

Here, in the hydraulic oil contamination state diagnostic device described in Patent Document 1, it is necessary to stabilize the flow velocity of the hydraulic oil in order to secure the detection accuracy of impurities, and the installation of the above-mentioned mini pump is indispensable.

In addition, since the hydraulic oil is collected from the hydraulic oil tank where the entire amount of the hydraulic oil is returned and the impurities mixed in the hydraulic oil are detected, it is possible to detect the contaminated state of the hydraulic oil, but the flood control It is difficult to detect the abnormal condition of the equipment that operates in, that is, the hydraulic equipment. When a hydraulic device becomes abnormal, impurities such as metal wear powder are generated in the casing of the hydraulic device in many cases, and the generated impurities are mixed in the hydraulic oil.

The present invention has been made in view of the above circumstances, and an object of the present invention is to stabilize the flow velocity of the hydraulic oil by a pump, and to detect an abnormal state of the hydraulic equipment. It is to provide the impurity detection apparatus inside.

The impurity detection device in hydraulic oil of the hydraulic equipment according to the present invention includes a sub tank that temporarily stores a predetermined amount of hydraulic oil and is installed at a height level at which the hydraulic oil flows out to the hydraulic oil tank due to natural flow. An oil flow path for connecting the sub tank and the hydraulic oil tank and allowing the hydraulic oil to flow out from the sub tank to the hydraulic oil tank by natural flow, and an oil flow path provided in the oil flow path to detect impurities mixed in the hydraulic oil. The sensor is provided in the oil flow path, and is provided with a communication valve for temporarily storing a predetermined amount of hydraulic oil in the sub tank and for communicating the sub tank and the hydraulic oil tank.

According to the above-mentioned impurity detection device according to the present invention, hydraulic oil can be flowed through an oil flow path provided with a sensor for detecting impurities without using a pump. By temporarily storing a predetermined amount of hydraulic oil in the sub tank, it is possible to stabilize the flow velocity of the hydraulic oil flowing through the oil flow path provided with the sensor when operating the sensor. That is, the impurity detection device according to the present invention does not require the flow rate stabilization of the hydraulic oil by the pump. Further, according to the above-mentioned impurity detection device according to the present invention, by providing a sub tank separately from the hydraulic oil tank, for example, the casing drain of the hydraulic motor and the hydraulic pump can be returned to the hydraulic oil tank via the sub tank, and various hydraulic cylinders can be used. It is possible to return the return oil directly to the hydraulic oil tank, and so on. This makes it possible to detect abnormal conditions of the flood control equipment, which was difficult to directly return the drains of all the hydraulic equipment to the hydraulic oil tank. That is, the impurity detection device according to the present invention can detect a state abnormality of a hydraulic device.

It is a block diagram of the apparatus configuration around the impurity detection apparatus including the impurity detection apparatus which concerns on one Embodiment of this invention.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. The impurity detection device according to the present invention is a device that operates hydraulically, that is, a device for detecting impurities such as metal abrasion powder and sand mixed in the hydraulic oil of the hydraulic device. The impurity detection device according to the present invention is applied to construction machinery such as a hydraulic excavator and a hydraulic crane equipped with a hydraulic device.

(Configuration of impurity detection device)
The configuration of the impurity detection device according to the embodiment of the present invention and the peripheral devices thereof will be described with reference to FIG.

The impurity detection device according to the embodiment of the present invention includes a sub tank 2 provided on the upper side surface of the hydraulic oil tank 1, a pipe 3 (oil flow path) connecting the bottom of the sub tank 2 and the hydraulic oil tank 1. A communication valve 4, a sensor 5, and an oil filter 6 (filter) provided in the pipe 3, an overflow pipe 16 (overflow flow path) for flowing hydraulic oil from the sub tank 2 to the hydraulic oil tank 1, and an upper part of the sub tank 2. It has an supplied air supply / exhaust valve 7 and a controller 14.

The hydraulic oil tank 1 is a tank for accommodating hydraulic oil for hydraulic equipment. The oil level upper limit level Lmmax and the oil level lower limit level Lmmin are preset in the hydraulic oil tank 1. An oil level gauge 10 is attached to the hydraulic oil tank 1. The liquid level of the hydraulic oil in the hydraulic oil tank 1 is constantly monitored by the oil level gauge 10.

A suction strainer 15 is attached to the bottom of the hydraulic oil tank 1. A filter chamber 11 is provided in the upper part of the hydraulic oil tank 1. The return filter 12 and the bypass check valve 13 are housed in the filter chamber 11. An air breather 9 is attached to the top of the hydraulic oil tank 1. The air breather 9 is a known device having an air supply / exhaust function and an air filter function. The space inside the hydraulic oil tank 1 (excluding the filter chamber 11) is set to a pressure higher than the atmospheric pressure by the air breather 9.

The sub tank 2 is a tank that temporarily stores the hydraulic oil discharged from the flood control device. The inner wall surface on the bottom side of the sub tank 2 is a slope 2a that is inclined with respect to the horizontal direction. One end of the pipe 3 is connected to the bottom of the sub tank 2 formed by the slope 2a. The other end of the pipe 3 is connected to the bottom side surface of the hydraulic oil tank 1. In the present embodiment, the inner bottom of the sub tank 2 has a mortar shape that descends toward the center thereof. An air supply / exhaust valve 7 is attached to the ceiling of the sub tank 2 via an air filter 8. The air supply / exhaust valve 7 is a valve for communicating the atmosphere with the inside of the sub tank 2. The air supply / exhaust valve 7 is, for example, a solenoid valve, and its opening / closing is controlled by the controller 14.

The communication valve 4, the sensor 5, and the oil filter 6 are provided in the pipe 3 in this order from the sub tank 2 side. The communication valve 4 is a valve for temporarily storing a predetermined amount of hydraulic oil in the sub tank 2 and for communicating the sub tank 2 and the hydraulic oil tank 1. The communication valve 4 is, for example, an electromagnetic valve, and its opening / closing is controlled by the controller 14. The sensor 5 is for detecting impurities mixed in the hydraulic oil, and is, for example, an optical sensor. When the sensor 5 is an optical sensor, the sensor 5 has, for example, a light emitting portion (not shown) and a light receiving portion (not shown) arranged on both sides of the pipe 3 so as to sandwich the pipe 3. The portion of the pipe 3 where the sensor 5 is arranged is made transparent, for example.

The oil filter 6 is for capturing impurities contained in the hydraulic oil flowing out from the sub tank 2.

The sub tank 2 is installed at a height level at which hydraulic oil flows out from the bottom thereof to the hydraulic oil tank 1 due to natural flow. In the present embodiment, the sub tank 2 is installed at a position where the height level Lsb of the inner bottom thereof is higher than the oil level upper limit level Lmmax of the hydraulic oil tank 1.

In addition, "the hydraulic oil flows out due to natural flow" means that the hydraulic oil flows out without using the power of a pump or the like.

The oil level upper limit level Lsmax is preset in the sub tank 2. The oil level upper limit level Lsmax is equal to the suction level of the overflow pipe 16. When the liquid level of the hydraulic oil in the sub tank 2 rises and reaches the oil level upper limit level Lsmax, the hydraulic oil in the sub tank 2 flows out from the overflow pipe 16 to the hydraulic oil tank 1. Here, as will be described in detail later, before the sensor 5 detects impurities mixed in the hydraulic oil, the communication valve 4 and the air supply / exhaust valve 7 are closed to store the hydraulic oil in the sub tank 2. Due to the presence of the overflow pipe 16, the liquid level of the hydraulic oil in the sub tank 2 does not exceed the oil level upper limit level Lsmax. In other words, due to the presence of the overflow pipe 16, the liquid level of the hydraulic oil in the sub tank 2 is maintained at the oil level upper limit level Lsmax. By setting the oil level upper limit level Lsmax of the sub tank 2, the flow velocity passing through the sensor 5 part of the hydraulic oil can be adjusted. The plank cross-sectional area of the sub tank 2 is determined, for example, by the expected operating time of the sensor 5. The larger the flat cross-sectional area of the sub tank 2, the longer the effective operating time of the sensor 5 can be secured. This is because the larger the flat cross-sectional area of the sub tank 2, the larger the amount of hydraulic oil temporarily stored in the sub tank 2.

The lower end (downstream end) of the overflow pipe 16 is positioned below the oil level lower limit level Lmmin of the hydraulic oil tank 1 so that the lower end is always submerged in the hydraulic oil.

In FIG. 1, a hydraulic pump 21, a hydraulic motor 22, a hydraulic cylinder 23, and control valves 24 and 25 are shown as examples of hydraulic equipment. The hydraulic pump 21 is driven by, for example, an engine (not shown) of a hydraulic excavator to discharge pressure oil. The hydraulic motor 22 rotates, for example, an upper swing body (not shown) of a hydraulic excavator. The hydraulic cylinder 23 is for operating, for example, a bucket of a hydraulic excavator. The control valve 24 is a valve that controls the supply and discharge of pressure oil to the hydraulic motor 22, and the control valve 25 is a valve that controls the supply and discharge of pressure oil to the hydraulic cylinder 23. The types and quantities of hydraulic equipment are not limited to the above.

As shown by the dotted line, the casing drain (drain oil (also hydraulic oil)) of the hydraulic pump 21 and the hydraulic motor 22 is put into the sub tank 2 from the bottom side surface of the sub tank 2. The casing drain is returned from the sub tank 2 to the hydraulic oil tank 1 via the overflow pipe 16 or the pipe 3. The return oil (hydraulic oil) discharged from the hydraulic motor 22 and the hydraulic cylinder 23 is directly returned to the hydraulic oil tank 1. The return oil (hydraulic oil) returned to the hydraulic oil tank 1 flows to the hydraulic pump 21 via the suction strainer 15 and is circulated for use. The piping through which the casing drain of the hydraulic pump 21 and the hydraulic motor 22 flows is arranged at a level lower than the height level Lsb of the inner bottom of the sub tank 2 except for the vicinity of the sub tank 2 connection portion.

(Operation of impurity detection device)
In the following description, it is assumed that each of the above-mentioned devices constitutes a hydraulic excavator.

When the engine of the hydraulic excavator is turned on, the controller 14 opens and closes the communication valve 4 and the air supply / exhaust valve 7. When the operator operates the hydraulic excavator, the hydraulic pump 21 causes the hydraulic oil to flow from the hydraulic oil tank 1 to each hydraulic actuator such as the hydraulic motor 22 and the hydraulic cylinder 23. The return oil (hydraulic oil) discharged from each hydraulic actuator such as the hydraulic motor 22 and the hydraulic cylinder 23 directly returns to the hydraulic oil tank 1. On the other hand, the casing drain of the hydraulic pump 21 and the hydraulic motor 22 (since the casing drain is also hydraulic oil, hereinafter, referred to as “hydraulic oil”) flows into the sub tank 2. At this time, since the communication valve 4 is closed, the hydraulic oil that has flowed into the sub tank 2 accumulates in the sub tank 2. When the liquid level of the hydraulic oil in the sub tank 2 reaches the oil level upper limit level Lsmax, the hydraulic oil in the sub tank 2 flows out from the overflow pipe 16 to the hydraulic oil tank 1. Since the lower end of the overflow pipe 16 is always submerged in the hydraulic oil, the hydraulic oil in the sub tank 2 operates from the overflow pipe 16 so that the hydraulic oil pushes away the air in the overflow pipe 16. It flows out to the oil tank 1. Since the hydraulic excavator travels on rough terrain and the equipment such as the engine vibrates during its operation, dust is likely to fly around the sub tank 2. The air filter 8 prevents dust and the like from entering the sub tank 2, but the air supply / exhaust valve 7 is closed to prevent dust from entering the sub tank 2. Further, as described above, the pressure inside the hydraulic oil tank 1 is higher than the atmospheric pressure. Further, the liquid level of the hydraulic oil in the hydraulic oil tank 1 fluctuates due to various operations of the hydraulic excavator. If the air supply / exhaust valve 7 is in the open state, the pressure in the sub tank 2 becomes atmospheric pressure, so that the hydraulic oil may flow back from the hydraulic oil tank 1 to the sub tank 2 via the overflow pipe 16. .. In addition, it does not always flow backward. By closing the air supply / exhaust valve 7, the backflow of hydraulic oil from the hydraulic oil tank 1 to the sub tank 2 is prevented.

Here, if a state abnormality occurs in the hydraulic pump 21 and / or the hydraulic motor 22, for example, metal wear powder (iron powder, etc.) is generated, and metal wear powder generated in the casing drain (hydraulic oil) thereof is generated. Is mixed. The metal wear debris flows into the sub tank 2 together with the hydraulic oil, and the wear debris having a large particle size settles on the bottom of the sub tank 2. Abrasion powder having a small particle size is suspended in the hydraulic oil.

The operator turns off the engine when the work on the hydraulic excavator is completed. When the engine is turned off, the controller 14 returns the communication valve 4 and the air supply / exhaust valve 7 from closed to open. When the communication valve 4 and the air supply / exhaust valve 7 are opened, the hydraulic oil mixed with impurities (metal wear debris, etc.) in the sub tank 2 operates through the pipe 3 under its own weight and atmospheric pressure due to natural flow. It flows toward the oil tank 1. At this time, the controller 14 operates the sensor 5 to measure the amount of impurities mixed in the hydraulic oil. Impurities that have passed through the sensor 5 portion are captured by the oil filter 6.

When the hydraulic oil in the sub tank 2 is exhausted, the flow velocity in the pipe 3 becomes zero, so that the impurities passing through the sensor 5 portion are eliminated. The controller 14 ends the measurement of impurities when, for example, the value measured by the sensor 5 stabilizes at zero.

The controller 14 determines whether or not the measured value of the impurity exceeds the threshold value of the abnormal state. The threshold value of the abnormal state is calculated by the controller 14 from information such as the operating time of the hydraulic equipment, the operation history, and the load history. The controller 14 outputs the determination result to the monitor.

(Modification example)
In the above-described embodiment, the inner bottom of the sub-tank 2 has a mortar shape that descends toward the center thereof. Instead of this, the inner bottom of the sub tank 2 may be shaped so as to descend toward the corner. In this case, the pipe 3 is connected to the bottommost portion located at the corner of the inner bottom of the sub tank 2. Further, the inner bottom of the sub tank 2 may be flat rather than tapered.

In the above-described embodiment, the air supply / exhaust valve 7 may be omitted. That is, the inside of the sub tank 2 may be in a state of always communicating with the atmosphere.

In the above-described embodiment, the overflow pipe 16 may be omitted. In this case, for example, when the oil level in the sub tank 2 reaches the oil level upper limit level Lsmax, the controller 14 opens the communication valve 4. The casing drain of the hydraulic pump 21 and the hydraulic motor 22 needs to have a flow path for being directly returned to the hydraulic oil tank 1.

In the above-described embodiment, the pipe 3 is used as an oil flow path for flowing out the hydraulic oil from the sub tank 2 to the hydraulic oil tank 1 by natural flow. A rubber hose or the like may be used as the oil flow path.

In the above-described embodiment, the casing drain of the hydraulic pump 21 and the hydraulic motor 22 is returned to the hydraulic oil tank 1 via the sub tank 2, and the return oil discharged from the hydraulic motor 22 and the hydraulic cylinder 23 is the hydraulic oil tank. It is returned directly to 1. There are various variations of whether the return oil of the hydraulic equipment is returned to the hydraulic oil tank 1 via the sub tank 2 or directly to the hydraulic oil tank 1.

In the above-described embodiment, the communication valve 4 and the air supply / exhaust valve 7 are opened / closed and the sensor 5 is operated under the control of the controller 14, but the communication valve 4 and the air supply / exhaust valve 7 are opened and closed, the sensor 5 is operated, and the like. May be done manually by a person.

(Action effect)
The impurity detection device described above includes a sub tank 2 that temporarily stores a predetermined amount of hydraulic oil, and a sub tank 2 and a hydraulic oil tank 1 that are installed at a height level at which the hydraulic oil flows out to the hydraulic oil tank 1 due to natural flow. 3 is provided in the pipe 3 for allowing the hydraulic oil to flow out from the sub tank 2 to the hydraulic oil tank 1 by natural flow, a sensor 5 provided in the pipe 3 for detecting impurities mixed in the hydraulic oil, and a pipe 3 are provided. A communication valve 4 for temporarily storing a predetermined amount of hydraulic oil in the sub tank 2 and for communicating the sub tank 2 and the hydraulic oil tank 1 is provided.

According to this configuration, hydraulic oil can be flowed through the pipe 3 provided with the sensor 5 for detecting impurities without using a pump. By temporarily storing a predetermined amount of hydraulic oil in the sub tank 2, the flow velocity of the hydraulic oil flowing through the pipe 3 provided with the sensor 5 can be stabilized when the sensor 5 is operated. Further, according to the above-mentioned impurity detection device, by providing the sub tank 2 separately from the hydraulic oil tank 1, the casing drain of the hydraulic motor 22 and the hydraulic pump 21 is returned to the hydraulic oil tank 1 via the sub tank 2, and the hydraulic motor 22 is used. , And the hydraulic oil (return oil) after operating the hydraulic cylinder 23 can be directly returned to the hydraulic oil tank 1. This makes it possible to detect impurities contained in the casing drains of the hydraulic motor 22 and the hydraulic pump 21, which was difficult to directly return the drains of all the hydraulic equipment to the hydraulic oil tank.

The impurity detection device described above is provided in the sub tank 2 and further includes an air supply / exhaust valve 7 for communicating the atmosphere with the inside of the sub tank 2.

According to this configuration, it is possible to prevent dust from entering the sub tank 2. Further, it is possible to prevent the backflow of the hydraulic oil from the hydraulic oil tank 1 to the sub tank 2.

The impurity detection device described above further includes an overflow pipe 16 that allows hydraulic oil to flow out from the sub tank 2 to the hydraulic oil tank 1 when the amount of hydraulic oil in the sub tank 2 reaches a predetermined amount.

According to this configuration, the amount of hydraulic oil temporarily stored in the sub tank 2 can be easily and surely set to a predetermined amount.

The inner wall surface on the bottom side of the sub tank 2 constituting the impurity detection device is a slope 2a that is inclined with respect to the horizontal direction, and the pipe 3 is connected to the bottommost portion of the sub tank 2 formed by the slope 2a. ing.

According to this configuration, impurities in the hydraulic oil that have settled on the bottom of the sub tank 2 can flow to the pipe 3 provided with the sensor 5 without leaving the impurities in the sub tank 2. As a result, the detection accuracy of impurities mixed in the hydraulic oil is improved.

In the above-mentioned impurity detection device, an oil filter 6 for capturing impurities is arranged in a portion of the pipe 3 on the downstream side of the sensor 5.

The hydraulic oil is supplied to the hydraulic equipment from the hydraulic oil tank 1. According to this configuration, impurities in the hydraulic oil in the sub tank 2 can be prevented from flowing out to the hydraulic oil tank 1. As a result, it is possible to prevent a secondary failure of the hydraulic equipment.

In the above-mentioned impurity detection device, the sub tank 2 is installed so that the height level Lsb of the inner bottom of the sub tank 2 is higher than the oil level upper limit level Lmmax of the hydraulic oil tank 1.

According to this configuration, all the hydraulic oil in the sub tank 2 can be more reliably flowed to the pipe 3 provided with the sensor 5.

1: Hydraulic oil tank 2: Sub tank 2a: Slope 3: Piping (oil flow path)
4: Communication valve 5: Sensor 6: Oil filter (filter)
7: Air supply / exhaust valve 14: Controller 16: Overflow pipe (overflow flow path)
21: Hydraulic pump (hydraulic equipment)
22: Hydraulic motor (hydraulic equipment)
23: Hydraulic cylinder

Claims (4)

A sub-tank that temporarily stores a predetermined amount of hydraulic oil, which is installed at a height level at which the hydraulic oil flows out to the hydraulic oil tank due to natural flow,
An oil flow path for connecting the sub tank and the hydraulic oil tank and allowing hydraulic oil to flow out from the sub tank to the hydraulic oil tank by natural flow.
A sensor provided in the oil flow path to detect impurities mixed in the hydraulic oil,
A communication valve provided in the oil flow path for temporarily storing a predetermined amount of hydraulic oil in the sub tank and for communicating the sub tank and the hydraulic oil tank.
An air supply / exhaust valve provided in the sub tank for communicating the atmosphere with the inside of the sub tank.
When the amount of hydraulic oil in the sub tank reaches a predetermined amount, an overflow flow path for flowing hydraulic oil from the sub tank to the hydraulic oil tank, and
A controller that controls the opening and closing of the air supply / exhaust valve, and a controller that opens and closes the air supply / exhaust valve when hydraulic oil is stored in the sub tank.
A device for detecting impurities in hydraulic fluid of hydraulic equipment. In the impurity detection device for hydraulic oil of a hydraulic device according to claim 1 .
The inner wall surface on the bottom side of the sub tank is a slope that inclines with respect to the horizontal direction.
An impurity detection device in hydraulic oil of a hydraulic device formed by the slope and having the oil flow path connected to the bottom of the sub tank. In the impurity detection device for hydraulic oil of a hydraulic device according to claim 1 or 2 .
A filter for capturing the impurities is arranged in a portion of the oil flow path on the downstream side of the sensor.
Impurity detection device in hydraulic fluid of hydraulic equipment. In the impurity detection device for hydraulic oil of a hydraulic device according to any one of claims 1 to 3 .
The sub tank is installed so that the height level of the inner bottom of the sub tank is higher than the oil level upper limit level of the hydraulic oil tank.
Impurity detection device in hydraulic fluid of hydraulic equipment.

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