JPH06213172A - Failure diagnostic device for hydraulic pump - Google Patents

Abstract

PURPOSE:To provide a failure diagnostic device of a hydraulic pump capable of reproducing a failure and capable of reducing the consumption of a battery. CONSTITUTION:A control device 21 is inputted with the signal X of an operating lever 9 and the displacement signal Y of a swash plate 6a following it. If the value of the signal Y does not reach within the allowable range of the signal X after the prescribed time elapses, an error flag '1' is stored in an EEPROM 29, a light emitting diode 13 is illuminated, and the failure of a hydraulic pump 6 is displayed. The error flag of the EEPROM 29 is not vanished after it is once stored regardless of the state of a power source, and the failure once occurring then disappearing can be reproduced. No backup is required for a RAM 26, and the consumption of a battery can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic pump used as a power source of a hydraulic machine such as a hydraulic excavator and a hydraulic crane, and a fault diagnosis device for a hydraulic pump for finding a fault related to the hydraulic pump.

[0002]

2. Description of the Related Art When a failure occurs in a hydraulic pump or a portion related to the hydraulic pump, it becomes difficult or impossible for a hydraulic machine using the hydraulic pump to perform a desired operation. Therefore, a failure diagnosis device that constantly diagnoses whether or not a failure has occurred in the hydraulic pump has been proposed, for example, in Japanese Patent Laid-Open No. 62-60990. The outline of the device described in this publication will be described with reference to the drawings.

FIG. 3 is a control circuit diagram of the apparatus. In the figure, 6 is a double displacement variable displacement hydraulic pump (hereinafter simply referred to as hydraulic pump), 6a is a variable displacement mechanism for the hydraulic pump 6 (hereinafter represented by a swash plate), and 7 is an input signal. It is a regulator that tilts the swash plate 6a accordingly. 8
Is a displacement meter that detects the amount of displacement of the swash plate 6a, and outputs an electric signal Y corresponding to the detected amount of displacement. An operation lever 9 operates the hydraulic pump 6, and outputs an electric signal X according to the operation amount. Reference numeral 10 is a pilot pump, 11 is a pressure gauge that detects the pressure of the pilot pump 10 and outputs an electric signal P corresponding thereto, and 12 is a hydraulic oil tank. 1
3 is a light emitting diode, 14 is a battery, and 15 is a key switch of a hydraulic machine.

Reference numeral 21 is a control device constituted by using a microcomputer, which inputs electric signals Y, X and P to perform predetermined calculation and control, outputs a control signal to the regulator 7 and emits light from the light emitting diode 13. A failure signal is output to. The control device 21 includes a multiplexer 22, an A / D converter 23, a CPU 24, a ROM 25, and an R
It is composed of an AM 26, an output unit 27, and power supply circuits 28A and 28B. The power supply circuit 28A is a circuit for supplying a predetermined voltage from the battery 14 to the control device 21 via the key switch 15, and the power supply circuit 28B backs up the stored contents of the RAM 26 so as not to be erased when the key switch 15 is opened. It is a circuit for doing.

An outline of the operation of the control device 21 will be described with reference to the flowchart shown in FIG. First, CPU2
4 reads the signals X, Y and P via the multiplexer 22 and the A / D converter 23 and stores them in the RAM 26 (procedure a). Next, the signals X and Y are extracted, a signal is output to the regulator 7 so that the difference between the two signals becomes 0, and the swash plate 6a is displaced by an amount according to the operation of the operation lever 9 (procedure b). Next, a permissible deviation is set before and after the signal X, and whether or not the signal Y is within the range of the permissible deviation (whether or not the swash plate 6a is tilted according to the operation amount of the operation lever). ), If it is within the range, the error flag stored in the ROM 26 is set to “0”, and if it is out of the range, the error flag is set to “1” and the failure determination is performed. (Procedure c).

Here, it takes a certain amount of time for the tilt of the swash plate 6a to reach the tilt amount that matches the operation signal.
In the meantime, in the process of step c, the failure signal is not output even if the error flag is "1". The time for this, that is, the error counter set value is calculated, but since the operating speed of the swash plate 6a depends on the hydraulic pressure that drives the regulator 7, the above calculation uses the standard error counter set value as the signal P. It is carried out by correcting accordingly (procedure d). Finally, even if the error flag is "1" in the process of step c, the output of the failure signal is delayed by the error counter set value obtained in the process of step d, and the time corresponding to the error counter set value is delayed. When the error flag remains “1” even after the elapse, a failure signal is output via the output unit 27 (procedure e). By the output of this failure signal, the light emitting diode 13 emits light to indicate the failure of the hydraulic pump.

[0007]

Normally, when a failure occurs in the hydraulic pump, the failure state continues until the repair is completed. However, in some hydraulic pump failures, the failure condition does not continue. For example, foreign matter is mixed into the hydraulic oil, and this foreign matter is caught in any part of the regulator 7, so that the operation of the regulator 7 is temporarily (1
Although the defective state occurs in 0 to 30 seconds), the foreign matter may flow out from the regulator 7 to the hydraulic oil tank 12 thereafter. In such a case, in the above-mentioned conventional device, the error flag becomes “1” and the light emitting diode 13 is turned on while the foreign matter is caught on the regulator 7. In this case, if the operator of the hydraulic machine notices that the light emitting diode 13 is lit, the hydraulic machine is stopped and a repair person is called, but when the repair person arrives, the foreign matter has already flowed out and the light emitting diode 13 is It is in the off state, the failure is not reproduced, and the presence of foreign matter is overlooked. Even if the operator does not notice the lighting of the light emitting diode 13, the presence of foreign matter is overlooked.

Further, the RAM 26 is backed up by the power supply circuit 28B as described above, but the amount of consumption of the battery 14 for this is extremely large. In particular,
If the hydraulic machine is not used for a long period of time, the starter cannot be started and the hydraulic machine cannot be used immediately even if the use of the hydraulic machine is restarted without noticing the exhaustion of the battery.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems in the prior art and to provide a failure diagnosing device for a hydraulic pump which has reproducibility of failures and which does not require a backup power supply circuit.

[0010]

In order to achieve the above object, the present invention relates to a hydraulic pump having a varnishing volume varying mechanism, operation signal generating means for generating a signal for operating the laurel volume varying mechanism, and Displacement signal detecting means for detecting a displacement signal of the displacement control mechanism, and comparing means for comparing the absolute value of the difference between the operation signal of the operation signal generating means and the displacement signal of the displacement signal detecting means with a predetermined allowable value. In a failure diagnosis device for a hydraulic pump, the EEPR stores an error code when the absolute value of the difference exceeds the allowable value by the comparing means for a predetermined time or more.
OM (Electrically Erasable a)
nd Programmable ROM) and this E
An output means for outputting a failure signal when the error code is stored in the EPROM is provided.

[0011]

When the comparing means determines that the absolute value of the difference between the operation signal of the operation signal generating means and the displacement signal of the displacement signal detecting means exceeds the allowable value, the error flag "1" is set to EEP.
Stored in ROM. When this state continues for a predetermined time or longer, a failure signal is output. Once the error flag "1" is stored in the EEPROM, the error flag retains the stored state even if the cause of the failure disappears, so that the presence or absence of the failure can be reproduced. Further, the use of the EEPROM eliminates the need for a backup power supply circuit.

[0012]

The present invention will be described below with reference to the illustrated embodiments. FIG. 1 is a control circuit diagram of a hydraulic pump failure diagnosis apparatus according to an embodiment of the present invention. In this figure, the same or equivalent parts as those shown in FIG. 25A is a ROM corresponding to the ROM 25 shown in FIG.
However, a part of the stored contents is different from the ROM 25. Reference numeral 29 represents an EEPROM. Reference numeral 16 is an erasing device for erasing the contents stored in the EEPROM 29.

Next, the operation of this embodiment will be described with reference to the flow chart shown in FIG. The operations of steps a to d of the conventional apparatus shown in FIG. 4 are performed as they are in this embodiment. When the new error counter set value C is obtained by the correction in the procedure d, the CPU 24 checks whether the error flag of the RAM 26 is "0" in the failure determination of the procedure c of FIG. 4 according to the program of the ROM 25A (procedure e1).
If it is "0", the error counter of the RAM 26 is set to "0" (procedure e2), and it is judged whether or not the erase instruction signal for the EEPROM 29 is inputted from the erasing device 16 (procedure e3). If not, the EEPROM 29 is inputted.
It is determined whether or not the error flag of is 1 (step e4),
If it is not "1", the process is returned to the start.

When it is determined in step e1 that the error flag of the RAM 26 is "1" (when it is determined that the signal Y is outside the allowable range of the signal X), the error counter of the RAM 26 is corrected and set in step d. It is judged whether or not the error counter has reached (whether or not the set time has elapsed) (procedure e5), and if not reached, "1" is added to the error counter of the RAM 26 (procedure e6), and the procedure e3, e
After the processing of step 4, the process returns to the start and this processing is repeated. If the signal Y falls within the allowable range of the signal X during this repetition, the error flag of the RAM 26 is set to "0" in the process of step c, this is determined in step e1, and the error counter is returned to "0". Be done.

When it is determined in step e5 that the error counter has reached the set value while the signal Y is outside the allowable range of the signal X, the CPU 24 determines whether the error flag of the EEPROM 29 is "1". Check whether or not (procedure e
7) If it is judged that it is not "1", E
If the error flag of the EPROM 29 is rewritten to "1" (step e9), or if it is "1", the above step e3 is executed as it is, and then the step e4 is executed if the erase instruction signal is not output. . In this case, the EEPROM 29
Error flag is "1", the light emitting diode 1
3 is turned on (procedure e8), the failure is displayed, and then the process returns to the start.

When the processing for the failure is carried out and the processing is completed, the repairer outputs an erasing instruction signal using the erasing device 16. The output of this erase instruction signal is determined in step e3,
In the next step e10, EEPRO which was "1" until then
The error flag of M29 is rewritten to "0".

As described above, in this embodiment, since the error flag is stored not only in the RAM 26 but also in the EEPROM 29, it is possible to reproduce a failure that has occurred once and then disappears. It is possible to take corrective measures and contribute to the prevention of failure occurrence. Also, R
Since the backup of the AM 26 is not required, the consumption of the battery 14 can be reduced, the starter can be started without any trouble, and the power supply circuit for backup can be omitted. The configuration can be simplified, and the battery 14 can be replaced without any trouble.

The effect of replacing the battery 14 will be described in more detail. In a conventional device that does not include the EEPROM 29, even if the ROM 26 is backed up, the ROM is replaced when the battery 14 is replaced.
The memory of 26 disappears. Therefore, if the accidental occurrence and the replacement of the battery 14 happen to coincide with each other, the failure is not diagnosed, which is inconvenient. Such an example is given below. When a failure occurs in a part of the control system of the hydraulic pump, the control of the hydraulic pump is disabled, and the engine that drives the hydraulic pump is overloaded and the engine stops, the operator of the hydraulic machine can handle this situation with the battery. It is often estimated that the battery 14 is consumed, and the battery 14 is replaced. By this replacement, the error flag indicating the failure of the hydraulic pump also disappears, and the trouble diagnosis device is no longer useful. However, in this embodiment, the EEPR
Since it has OM29, the error flag does not disappear,
It is possible to make a reliable failure judgment.

In the description of the above embodiment, an example of displaying a failure by the light emitting diode 13 has been described.
The present invention is not limited to this, and a display device carried by a repair person may be connected instead of or together with the light emitting diode.

[0020]

As described above, according to the present invention, the error flag is stored not only in the RAM but also in the EEPROM. Therefore, it is possible to reproduce a failure that has occurred once and then disappeared. Can be dealt with reliably and contribute to prevention of failure occurrence. Also, RA
Since the backup of M is not required, the consumption of the battery can be reduced, the starter can be started without any trouble, and the power supply circuit for the backup can be omitted. It can be simplified and the battery can be replaced without any trouble.

[Brief description of drawings]

FIG. 1 is a control circuit diagram of a failure diagnosis device for a hydraulic pump according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating an operation of the control device shown in FIG.

FIG. 3 is a control circuit diagram of a conventional hydraulic pump failure diagnosis device.

FIG. 4 is a flowchart illustrating an operation of the control device shown in FIG.

[Explanation of symbols]

 6 Hydraulic Pump 7 Regulator 9 Operating Lever 13 Light Emitting Diode 14 Battery 15 Key Switch 16 Eraser 21 Control Device 25A ROM 26 RAM 29 EEPROM

Claims (2)

[Claims] 1. A hydraulic pump having a displacement control mechanism, an operation signal generation means for generating a signal for operating the displacement control mechanism, and a displacement signal detection means for detecting a displacement signal of the displacement control mechanism. In a failure diagnosis device for a hydraulic pump, comprising: a comparison unit that compares the absolute value of the difference between the operation signal of the operation signal generation unit and the displacement signal of the displacement signal detection unit with a predetermined allowable value. EEPR that stores an error code when the absolute value of the difference exceeds the allowable value for a predetermined time or more
A failure diagnosis device for a hydraulic pump, comprising: an OM; and an output means for outputting a failure signal when the error code is stored in the EEPROM. 2. The EEPROM according to claim 1,
Is a fault diagnosis device for a hydraulic pump, characterized in that it is provided with erasing means for erasing the stored contents.