JP2008232244A - Hydraulic driving device having filter pressure control mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydraulic driving device for improving operability and maintainability of a hydraulic device, by quickly coping with clogging of a filter and mixing of foreign matter in a hydraulic fluid, by always grasping the clogging of the filter and a foreign matter fixing-in state of the hydraulic fluid, by momentarily detecting a time change in filter pressure (a pressure loss in the filter). <P>SOLUTION: This hydraulic driving device is characterized by having a pressure sensor for detecting the filter pressure in a hydraulic circuit to a hydraulic actuator and a timer for counting operation time of the pressure sensor, and having a filter pressure controller for determining an excess of the foreign matter in the hydraulic fluid when a filter pressure time change calculation value exceeds a filter pressure time change allowable value, by comparing the filter pressure time change calculation value with the filter pressure time change allowable value, by calculating the time change in the filter pressure based on a storage value of the filter pressure from a pressure storage means for storing a filter pressure detecting value with the lapse of time and a time signal from the timer. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a hydraulic drive device that is applied to a hydraulic circuit or the like of a construction machine and is provided with a filter that filters foreign matter in the hydraulic oil in a hydraulic circuit to a hydraulic actuator driven by the hydraulic oil.

  A hydraulic circuit of a hydraulic excavator is usually provided with a plurality of oil filters (hereinafter referred to as filters). However, depending on the operation site of the hydraulic excavator, there is an environment in which foreign substances such as dust are likely to be mixed into the hydraulic oil. Filters are likely to be clogged. Such a foreign matter mixing state of the clogged hydraulic oil in the filter is grasped by monitoring the filter inlet pressure as disclosed in, for example, Japanese Patent Laid-Open No. 9-250510.

  That is, in Patent Document 1, a pressure detection sensor that detects a pressure loss of a filter, a contamination level detection sensor that detects a contamination level in hydraulic oil, and an output that decreases the output of the hydraulic circuit by reducing the engine speed. Reducing means, and when the pressure loss detection value of the pressure detection sensor exceeds a preset allowable value, the output reducing means is operated to reduce the output of the hydraulic apparatus to protect the hydraulic apparatus. ing.

JP-A-9-250510

As described above, the filter installed in the hydraulic circuit of the above-described hydraulic excavator is in an environment where foreign matters such as dust are likely to be mixed into the hydraulic oil depending on the operation site of the hydraulic excavator. easy.
For this reason, as in the technique of Patent Document 1 (Japanese Patent Laid-Open No. 9-250510), the pressure loss of the filter is detected by the pressure detection sensor, and the pressure loss detection value becomes equal to or greater than a preset allowable value. When the output reduction means is activated, the filter clogging cannot be detected until the pressure loss reaches the allowable value. There is a possibility that the maintenance of the hydraulic excavator is deteriorated due to delay in dealing with foreign matters mixed in the clogged hydraulic oil, and the operation of the hydraulic excavator may be hindered.

  In view of such a problem of the prior art, the present invention detects the time change of the filter pressure (filter pressure loss) from time to time, and constantly grasps the foreign matter contamination status of the clogged hydraulic oil. It is an object of the present invention to provide a hydraulic drive device that improves the operability and maintenance of a hydraulic device by speeding up measures against clogged hydraulic oil contamination.

  The present invention achieves the above-mentioned object, in a hydraulic drive device in which a filter for filtering foreign matter in the hydraulic oil is installed in a hydraulic circuit to a hydraulic actuator driven by the hydraulic oil. A pressure sensor for detecting the pressure of the filter, and a timer for measuring the operation time of the pressure sensor, and a pressure storage means for storing the filter pressure over time based on the detected value of the filter pressure input from the pressure sensor; A pressure time change calculating means for calculating a time change in filter pressure based on a stored value of the filter pressure from the pressure storage means and a time signal from the timer; and a pressure time in which an allowable value for the filter pressure time change is set. Change allowable value setting means, calculated value of filter pressure time change from pressure time change calculation means, and pressure When the calculated value of the filter pressure time change exceeds the filter pressure time change allowable value by comparing with the allowable value of the filter pressure time change set in the interval change allowable value setting means A filter pressure controller having a pressure time change determining means for determining is provided (claim 1).

Further, the present invention can be configured as follows in addition to the above configuration.
That is, the filter pressure controller estimates the time until the filter pressure time change reaches the allowable value of the filter pressure time change based on the calculated value of the filter pressure time change, and displays the estimated time on the display device. (Claim 2).

Further, in addition to the above configuration, the following configuration is preferable.
The filter pressure controller is configured to send an alarm to the alarm device when it is determined that the filter pressure is excessive in the change in the filter pressure time (Claim 3).

According to the present invention, a pressure sensor for detecting the pressure of the filter and a timer for measuring the operation time of the pressure sensor are provided, and the detected value of the filter pressure from the pressure sensor is sent to the filter pressure controller. In the filter pressure controller, the detected value of the filter pressure from the pressure sensor is memorized over time, the time change of the filter pressure is calculated using the time signal from the timer, and the filter pressure time When the calculated value of the change is compared with a preset allowable value of the change in the filter pressure time, and the calculated value of the change in the filter pressure time exceeds the allowable value of the change in the filter pressure time. Since it is configured to determine (Claim 1), the time change of the filter pressure (pressure loss of the filter) and the filter pressure Noborido able momentarily detect the eyes of the filter clogging, the contamination condition of the working oil is possible always accurately detected, it can predict the time to replace the cleaning time or the filter element of the filter element hydraulic oil early. If there is an excessive amount of foreign matter in the hydraulic oil, the damage to the hydraulic equipment can be minimized by exchanging the filter element and hydraulic oil.
As a result, it is possible to deal with foreign matters mixed in the filter clogged hydraulic oil at an early stage and at a necessary timing, thereby improving maintenance and suppressing a reduction in the operating rate of the hydraulic device.

  Further, the filter pressure controller estimates the time until the filter pressure time change reaches the allowable value of the filter pressure time change based on the calculated value of the filter pressure time change, and displays the estimated time on the display device. If it is configured (Claim 2), it is very easy to determine how long it will take to clean the filter element or replace the filter element / hydraulic oil when the filter is in use, simply by looking at the display device. it can. This improves the maintainability of the hydraulic device.

  Further, if the filter pressure controller is configured to send an alarm to the alarm device when it is determined that there is an excess of foreign matter in the hydraulic oil in the filter pressure time change (Claim 3), the filter pressure time change is allowed. When the value is exceeded, the alarm from the alarm device can quickly take measures such as cleaning the filter element or replacing the filter element / hydraulic oil, and can maintain the operation stability of the hydraulic drive device.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
In FIG. 4 showing a hydraulic excavator to which the present invention is applied, a hydraulic excavator denoted by reference numeral 1 includes a hydraulic excavator main body (upper turning body) 3, a lower traveling body (crawler) 2, a boom 8, an arm 9, An excavation bucket 10 attached to the tip, a boom drive cylinder 11, an arm drive cylinder 12, a bucket drive cylinder 13, and the like for driving the boom 8, the arm 9, and the bucket 10, respectively, are provided.

FIG. 1 is a system diagram of a hydraulic drive device for a hydraulic excavator according to an embodiment of the present invention. In FIG. 1, this hydraulic drive device includes a hydraulic pump 14, a pilot pump 15, an oil tank 16, left and right travel motors 5 and 6, a swing motor 7, a boom drive cylinder 11, and an arm drive. Control valves 17, 18, 19, 20, 21, 22 of the cylinder 12 and the bucket drive cylinder 13, pilot valves 23, 24, 25, 26, 27, 28 for switching these control valves 17 to 22 are provided. .
In the hydraulic drive device, a first filter 29 with a relief valve 29a is installed in a main oil passage A from the tank port of each of the control valves 17 to 22 to the oil tank 16, and each pilot valve from the pilot pump 15 is installed. A second filter 30 with a relief valve 30a is installed in the pilot pump oil passage B that reaches the pump ports 23 to 28.

The above configuration is the same as that of a hydraulic drive device of a normal hydraulic excavator. The present invention relates to a filter pressure control mechanism in such a hydraulic drive device.
In FIG. 1, the filter controller denoted by reference numeral 60 includes a detected value of the filter pressure of the first filter 29 detected by the first pressure sensor 51 and the second filter 30 detected by the second pressure sensor 52. Each of the detected values of the filter pressure is input. The filter pressure detected by the first pressure sensor 51 and the second pressure sensor 52 is the filter inlet pressure of the first filter 29 and the second filter 30, and is between the oil inlets and outlets of the first filter 29 and the second filter 30. Pressure difference (that is, pressure loss).
In addition, a time signal is input from the timer 54 to the filter controller 60. The filter controller 60 displays the filter pressure control calculation result on the display device 55 and outputs an alarm to the alarm device 53 based on the filter pressure control calculation result.

  Next, filter pressure control of the hydraulic apparatus having the above-described configuration according to the first embodiment of the present invention will be described with reference to FIG. In the following description, the case where the pressure detection signal from the first pressure sensor 51 for the first filter 29 is used will be described. However, the pressure detection signal from the second pressure sensor 52 for the second filter 30 is described. The same applies to the case of using.

The detection value of the filter pressure in the first filter 29 from the first pressure sensor 51 is continuously input to the pressure storage means 61 of the filter controller 60, and the pressure storage means 61 stores the detection value of the filter pressure. It is memorized over time and inputted to the pressure time change calculating means 62. The timer 54 generates a time signal simultaneously with the detection of the filter pressure from the first pressure sensor 51 and inputs the time signal to the pressure time change calculation means 62.
The pressure time change calculating means 62 calculates the time change of the filter pressure as shown by line A in FIG. 3 based on the detected value of the filter pressure with time and the time signal from the timer 54, and the pressure time Input to the change determination means 64.

In the pressure time change allowable value setting means indicated by reference numeral 63, the filter pressure time change allowable value, that is, the first filter 29 is clogged as shown in FIG. The limit value of the filter pressure time change that requires the cleaning or replacement of the filter element or the replacement of the hydraulic oil is set in advance by experimental results or simulation calculation.
The pressure time change determining means 64 compares the calculated value of the filter pressure time change (A line in FIG. 3) with the allowable value of the filter pressure time change (line B in FIG. 3) to determine the filter pressure. When the calculated value of the time change exceeds the allowable value of the filter pressure time change (the Z point or more in FIG. 3), it is determined that there is excessive contamination of the hydraulic oil.

  The determination result is displayed on the display device 55 and transmitted to the alarm device 53, and the alarm device 53 issues an alarm of excessive contamination of the clogged hydraulic oil in the first filter 29.

According to the first embodiment described above, the pressure sensor (the first pressure sensor 51 in this example) that detects the pressure of the filter (the first filter 29 in this example) and the timer 54 that measures the operating time of the pressure sensor 51. The filter pressure detection value from the pressure sensor 51 and the time signal from the timer 54 are respectively input to the filter pressure controller 60, and the filter pressure controller 60 detects the filter pressure from the pressure sensor 51. The value is stored over time, the time change of the filter pressure is calculated using the time signal from the timer 54 (A line in FIG. 3), and the calculated value of the filter pressure time change and a preset filter are calculated. Compared with the allowable pressure time change value (line B in FIG. 3), the calculated filter pressure time change value exceeds the allowable filter pressure time change value. Since it is determined that the filter pressure is excessive (Z point or more in FIG. 3), the time change of the filter pressure (filter pressure loss) and the degree of increase of the filter pressure can be detected momentarily. The clogging state can be detected with high accuracy at all times, and the filter element cleaning time or filter element replacement time can be predicted early.
As a result, it is possible to cope with foreign matter contamination of the filter clogged hydraulic oil at an early stage and at a necessary timing, thereby improving maintenance and suppressing a reduction in the operating rate of the hydraulic device.

In the second embodiment of the present invention, in the filter pressure controller 60, the calculated value of the filter pressure time change shown by the A line in FIG. 3 is calculated based on the calculated value of the filter pressure time change in the first embodiment. The degree of increase in the calculated value of the filter pressure time change (A line in FIG. 3) at an arbitrary time t before reaching the point where the filter pressure time change allowable value indicated by the B line is reached (that is, the Z point in FIG. 3) That is, an estimated time from the time point to the arrival point (Z point), that is, an estimated time until the filter element is cleaned or replaced is calculated based on the gradient of the A line.
The filter pressure controller 60 causes the display device 55 to display the estimated time until the filter element is cleaned or the filter element / hydraulic oil is replaced.

  According to the second embodiment, when the filter is in use, it is very easy to see how much time is required to clean the filter element or to replace the filter element / hydraulic oil by simply viewing the display device 55. I can judge. This improves the maintainability of the hydraulic device.

  Further, in the first and second embodiments, by providing the alarm device 53, when the change in the filter pressure time exceeds an allowable value, the filter element is cleaned or the filter element is activated by the alarm from the alarm device 53. It is possible to quickly deal with oil exchange and the like, and to maintain the operational stability of the hydraulic drive device.

  According to the present invention, the time change of the filter pressure (filter pressure loss) is detected every moment, and the clogging status of the filter is constantly grasped, thereby speeding up the countermeasure against foreign matters mixed in the filter clogging hydraulic oil. Further, it is possible to provide a hydraulic drive device that improves the operability and maintenance of the hydraulic device.

1 is a system diagram of a hydraulic drive device for a hydraulic excavator according to first and second embodiments of the present invention. FIG. It is a control block diagram of the filter pressure in 1st Example of this invention. It is a time change diagram of filter pressure in the 1st example. 1 is an external perspective view of a hydraulic excavator to which the present invention is applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hydraulic excavator 29 1st filter 30 2nd filter 51 1st pressure sensor 52 2nd pressure sensor 53 Alarm apparatus 54 Timer 55 Display apparatus 60 Filter controller 61 Pressure memory means 62 Pressure time change calculation means 64 Pressure time change determination means

Claims (3)

In a hydraulic drive device in which a filter for filtering foreign matter in the hydraulic oil is installed in a hydraulic circuit to a hydraulic actuator driven by the hydraulic oil,
A pressure sensor for detecting the pressure of the filter in the hydraulic circuit, and a timer for measuring the operation time of the pressure sensor;
Pressure storage means for storing the filter pressure over time based on the detected value of the filter pressure input from the pressure sensor;
Pressure time change calculating means for calculating the time change of the filter pressure based on the stored value of the filter pressure from the pressure storing means and the time signal from the timer;
Pressure time change allowable value setting means in which the filter pressure time change allowable value is set;
The calculated value of the filter pressure time change is compared with the calculated value of the filter pressure time change from the pressure time change calculation means and the allowable value of the filter pressure time change set in the allowable pressure time change value setting means. A hydraulic drive apparatus equipped with a filter pressure control mechanism, characterized by comprising a filter pressure controller having a pressure time change determining means for determining an excess of foreign matter in the hydraulic oil when a pressure time change allowable value is exceeded.   The filter pressure controller estimates a time until the filter pressure time change reaches an allowable value of the filter pressure time change based on the calculated value of the filter pressure time change, and displays the estimated time on a display device. 2. A hydraulic drive apparatus comprising the filter pressure control mechanism according to claim 1, wherein the hydraulic drive apparatus is configured.   The said filter pressure controller is comprised so that an alarm may be transmitted to an alarm device, when the excess of the foreign material in hydraulic fluid is determined in the said filter pressure time change. A hydraulic drive device comprising the filter pressure control mechanism according to claim 1.

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