JPS6030491A - Failure diagnostic device for oil-hydraulic pump - Google Patents

Abstract

PURPOSE:To have quick diagnosis of possible failure in a pump, which shall not require separation of any hydraulic piping, by comparing the absolute value of the difference between the displacement signal and a specific operation signal for judgement with a certain tolerable value, and by emitting a failure signal when this absolute value is going to exceed the tolerable value. CONSTITUTION:Operation signal X for a control lever 9 is passed through a filter circuit 11 to be converted ther into an operation signal for judgement X' as the change speed being below the max. displacement speed of a swash plate 6a. This signal X' is fed into an adding circuit 13a of a failure judging circuit 12, where an addition is made to the tolerable value DELTA. The sum (X'+DELTA) obtained is compared with the signal Y at a comparator 14a, and if the signal Y exceeds the sum, the comparator 14a generates a high level output 1. The signal X' is fed into another adding circuit 13b to undergo there a subtraction with the tolerable value DELTA, and the difference (X'-DELTA) is compared with the signal Y at another comparator 14b. If Y<(X'-DELTA), the comparator 14b emits output 1. That is, the absolute value of the difference between the signals Y and X' exceeds the tolerable value DELTA, a failure signal is given to a diode 16.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a failure diagnosis device for a hydraulic pump that is widely used as a power source for hydraulic excavators, cranes, and various other hydraulic machines and hydraulic devices.

Hydraulic pumps are the most important machines in hydraulic excavators, cranes, other hydraulic machines, and hydraulic equipment that generate hydraulic energy.If the hydraulic pump malfunctions or its performance deteriorates due to aging, etc. Doing so may cause military-related obstacles to the operation of machinery and equipment that are sourced from such equipment. Sixth, it is required that the hydraulic pumps used be checked. In this way, the hydraulic pump is checked and its failure or performance deterioration (hereinafter referred to as failure) is performed.

) A conventional device that performs the determination will be described.

No. 11a is a hydraulic circuit diagram of a conventional failure diagnosis device. 1
1 is a variable displacement hydraulic pump to be diagnosed, 1a is a displacement variable mechanism of the variable displacement hydraulic pump (hereinafter, this is represented by a swash plate), and 2 is a swash plate 1at that changes the displacement according to the discharge pressure of the variable displacement hydraulic pump. The regulator to be operated, 4, is the sixth oil pressure tester for diagnosis. The oil pressure tester 4 is composed of a pressure gauge 4a for measuring oil pressure, a flow meter 4b for measuring the flow rate of oil, and a manual variable throttle force 4c for squeezing the discharge line of the variable displacement hydraulic pump 1 and increasing the discharge pressure. ing. Reference numeral 5 denotes a tachometer connected to the variable displacement hydraulic pump 1 to measure its rotation speed. Note that 3a is a variable displacement hydraulic pump 1 and a hydraulic tester 4.
3b is the hydraulic tester 4
It shows piping such as a hydraulic hose that connects the pipe to the hydraulic oil tank.

To diagnose the failure of the variable displacement hydraulic pump l, first,
The piping connected to the discharge side of the variable displacement hydraulic pump 1 is separated at the portion a and the portion shown in the figure, and the piping 3a, 3b and the hydraulic tester 4 are all connected between the portions a and b. Next, the variable displacement hydraulic pump 1 is connected to a prime mover such as an engine (not shown).
The variable capacity hydraulic pump at that time is driven by 10 rotations N.
・Measure with tachometer 5. In this state, the variable throttle 4cf is operated, and the pressure of the pressure gauge 4a (discharge pressure of the variable displacement hydraulic pump 1) reaches the set value P. The pipe line is throttled 9 until fK is reached, and the discharge amount Q of the variable displacement hydraulic pump 1 at this time is measured using the flowmeter 4bK. In this case, the discharge bone is determined by the position ζ of the swash plate 1a which is controlled inversely by the regulator 2 (()) according to the discharge pressure. Next, based on the rotation speed N and the set pressure Pref, The theoretical discharge amount Qy6f of the variable displacement hydraulic pump 1 is calculated.Finally, this discharge amount Qr
ef and the measured large discharge amount Q, and if the difference exceeds the allowable value, it is determined that the variable displacement hydraulic pump 1 is in a failure state.

Although such a conventional failure diagnosis device can perform a failure diagnosis, when performing a diagnosis, a part of the hydraulic piping that has been completely installed is cut off and the piping 3a is removed.

3b, it is necessary to install the hydraulic tester 4, which takes a lot of time, and also, when cutting the hydraulic piping, there is a risk that dust or other particles may get mixed into the piping. moreover,
Concession itself, variable aperture,! ; Pressure gauge 4a by operating 14c,
The indicated value of the flow meter 4b must be read, which also requires a lot of time and diagnosis is troublesome and troublesome. Furthermore, 4C again,
In cases where large hydraulic excavators are manufactured using a large number of hydraulic pumps, it is known that a hydraulic pump failure is likely to occur.
Ij': With the conventional failure diagnosis device, it takes a lot of time to find out which hydraulic pump is malfunctioning.

The purpose of the present invention is to solve the above-mentioned problems of the conventional technology, and to solve the above-mentioned problems without having to disconnect the hydraulic piping or install the hydraulic tester.
In addition to being able to automatically and quickly perform fault diagnosis, it is also possible to simultaneously perform fault diagnosis for a large number of hydraulic pumps.
l? To provide a hydraulic pump failure diagnosis device that can perform

In order to achieve this object, the present invention limits the command value for displacing the variable displacement mechanism of the hydraulic pump by a required amount so that the rate of change is equal to or less than the maximum displacement speed of variable displacement displacement 4B < 2H, The absolute value of the difference between the signal that has passed through this limit and the displacement amount of the large displacement variable mechanism displaced by the command value is compared with a predetermined tolerance value, and when the absolute value exceeds the tolerance value, the hydraulic pump The present invention is characterized in that it outputs a failure signal indicating a failure. .

Hereinafter, the present invention will be explained based on the illustrated embodiment. FIG. 2 is a block diagram of a failure diagnosis apparatus for a hydraulic pump according to a first embodiment of the invention. In the figure, 6 is a double tilting type variable displacement hydraulic pump (hereinafter simply referred to as a hydraulic pump) that is subject to failure diagnosis, 6a is the I plate of the hydraulic pump 6, and a variable displacement mechanism such as the e'' shaft. (Hereinafter, this will be represented by a swash plate.) 7 is a swash plate IV drive device that drives the metal plate 6a according to an input signal, 8 is a displacement meter that detects the amount of displacement of the swash plate 6a, 9 is an operating lever for sweeping the hydraulic pump 6. The displacement meter 8 detects and outputs a displacement signal Y'(r) according to the amount of displacement of the large swash plate, and the operating lever 9 is operated to output ft, ft, according to the amount of fc. Outputs the operation signal X. 10 is the operation lever 9
A control (+tll) that can drive and control the swash plate 6a according to the operation of
'! 'i' In iR, input the signal Y of the displacement meter 8 and the signal
)'(i-calculated, and inputs the number 6 according to the difference to the swash plate drive device 7() to drive the swash plate 6a in accordance with the operating lever 9. In this way, the swash plate 6a moves to the operating lever. e') When the output signal of the displacement meter that detects the displacement of the plate 6a is equal to the output signal X of the Y-bar operation lever 9, f; Stop output to 7.

11 is a rough hole filter circuit connected to the operating lever 9;
When the rise and fall of the operation signal X is steep, this 1 is output as a gentle signal, and when the rise and fall of the operation signal Output ↑ Has good ability.

The output signal of the filter circuit 11 is used as the determination operation signal X'. 12 is a failure determination circuit for the hydraulic pump 6, two adder circuits 13a, 13b, and two comparators 14a, 14b.
and one OR circuit 15, the arithmetic circuit 13b subtracts the allowable value Δ from the signal X' (adds 1 Δ to X').

Further, the comparator 14a compares the added value of the adder 13a with the signal Y, and produces an output when the signal Y exceeds the added value. The comparator 14b compares the subtraction value output from the adder 13b with the signal Y, and produces an output when the signal Y is less than the subtraction value. Additionally, the OR circuit 15 connects the comparators 14a, 14
A signal b is input, and a signal is output when an output is generated in either comparator 14a or 14b. 16 is OR circuit 1
A light emitting diode not connected to 5 is turned on by the output signal of the OR circuit 15.

Here, the allowable value Δ will be explained. Normally, in a structure such as a swash plate of a hydraulic pump, the operation signal X and the displacement signal Y do not completely match, and a difference occurs due to mechanical play or accuracy of the swash plate drive mechanism. However, if such mechanical play is within a certain range, there is no problem with the operation of the hydraulic pump, and there is no need to consider this as a malfunction. Therefore, the sixth step is to exclude the difference between signal X and signal Y caused by mechanical play within a certain range from failure. determined by.

Next, the operation of this embodiment will be explained with reference to FIGS. 3(a) to 3(C). When the operating lever 9 is operated, the swash plate 6a
is driven according to the deviation between the operation signal X and the displacement signal Y, and follows the movement of the operation lever 9. By the way, the control lever 9
is operated by an operator, and the speed of the operation varies.

When the operation speed is slow, the rising edge of the operation signal The rise of X becomes steep (the speed of change of signal X is slow), and the swash plate 6a cannot follow this operation, resulting in a slight delay.

If there is a delay in the movement of the swash plate 6a, this delay will naturally appear in the displacement signal YK, so the discrimination circuit 12 that can compare the operation No. 4J Even if there is a delay, a fault (i) is output for the period of the delay.The filter circuit 11 prevents a fault signal from being erroneously generated even if there is a delay in the movement of the swash plate 6a. The time constant of the filter circuit 11 is set so as to limit the rate of change of the operation signal X to a value equal to or less than the maximum displacement speed of the swash plate 6a. 11, the determination operation signal X' whose rate of change is less than the maximum displacement rate of the swash plate 6a is obtained.

The operating signal X' for determining whether or not the signal is output from the filter circuit 11 is inputted to the addition circuit 13aK of the failure determination circuit 12, and is added to the allowable value Δ. This added value (X'+Δ) is compared with the signal Y in the comparator 14a, and the signal Y becomes the added value (X'
+Δ) is exceeded, the comparator 14a generates ``收士斤千''. This state exceeds K (X' + Δ) in Figure 3 (a)
>(X'+Δ), the comparator 14a outputs "1". If the signal Y exceeds the added value (X'+Δ), it means that a failure greater than the above-mentioned tolerable mechanical play has occurred in the hydraulic pump 6, and L7' (therefore,
The output "1" of the comparator 14a indicates a failure of the hydraulic pump.

Similarly, the signal X' is inputted to the adder circuit 13bKf, where the tolerance value Δ is subtracted, and the subtracted value (X'-Δ)U is compared with the signal Y by the comparator 14b, as shown in FIG. 3(b) K. As Y≧(X'-Δ), the 5 comparator 14b outputs "0".
", when y<(x'-Δ), the comparator 14b outputs "1"
becomes. As described above, comparators 14a and 14b
By comparing the signal Y with the addition value and the signal Y with the subtraction value, or in other words, by comparing the absolute value of the difference between No. 48 Y and the signal X' with the tolerance value Δ. , it is possible to detect all faults appearing in the movement of the swash plate 6a. Comparator 14a.

Since the output of 14b is manually input to the simultaneous KOR circuit 15,
The OR circuit 15 is connected to the comparator 14a as shown in FIG. 3(c)K.
, when the output of Isunaka of 14b becomes "1", "1"
'' and lights up the light emitting diodes 16. In other words, in the normal case where the swash plate 6a is controlled to follow the operation signal of the operation switch 9, the signal Y is X'-Δ≦ Y≦X′
+Δ, no signal is output from the OR circuit 14, and the light emitting diode 16 is in an off state TPAK. or,
When the swash plate 6a is no longer controlled due to a failure of the hydraulic pump, No. 13 Y outputs a signal from the OR circuit 15 that is outside the range of X'-Δ≦Y≦X'+Δ, and lights up the light emitting diode 16. indicates a hydraulic pump failure.

In addition, in place of the light emitting diode 16, other indicators or alarms, or a hole can be used in combination with these, and the output of the OR circuit 15 can be used in combination with an indicator or a sound alarm, or can be used alone to control hydraulic pressure. It can also be used to drive a non-electric stop mechanism of a pump or to operate a failure monitor. and,
When the output of the OR circuit 15 is used to drive the hydraulic pump to stop the hydraulic pump in an emergency, installing the filter circuit 11 to prevent a fault signal from being generated erroneously can avoid unnecessary force stopping of the hydraulic pump. It has a thick effect.

In this way, in this embodiment, two adder circuits, two comparator circuits, and an OR circuit are used, and the filter circuit is used to convert the addition and subtraction values of the mei-rokubanshi operation signal and the tolerance value into displacement signals, respectively. When the displacement signal is outside the predetermined range, a signal is output to indicate the error (i). Therefore, the hydraulic pressure is always automatically and quickly maintained without disconnecting the hydraulic piping or installing the tester. Pump failure diagnosis can be performed.Furthermore, since the failure judgment circuit can be constructed in a small and inexpensive manner, each hydraulic pump can be installed individually.Furthermore, since there are 6 filter circuits installed, the remaining 1 It is possible to completely prevent the generation of temporary failure signals due to delays in plate follow-up, and to generate failure <a only for steady failures.

FIG. 4 is a block diagram of a failure diagnosis device for a hydraulic pump according to a second embodiment of the present invention. In the figure, the same parts as those shown in FIG. .17id
It is a six-control device that is controlled using a microcomputer, and inputs a displacement signal Y to the operation unit No. Output. this control device], 7
The control device 10 and the failure determination circuit 12 in the 1tjP embodiment are also included. 18 is signal X
19 is an A/D converter that converts signal X and signal Y into digital values; 20 is an A/D converter that converts signals C?U that performs gain I (central processing residual β:), 21
The CPU 20's performance 41, the controller's child ROM (read only memory), 22 (r:i
RAM that temporarily stores input data, calculated values, etc.
(Random access memory), 23 is an output phase for outputting to the swash plate drive device 7 and the light emitting diode 1;

For the operation of this embodiment, please refer to the flowcharts shown in Figures 5L1 to 8. 1st, J sakushin@X and displacement (J No.
1 is written on the RA hook 22 via the A/D converter 19 (fifth block a). Next, move the I board 6a '1lii! Let's go to Obon (a! Figure 5 block b).

The detailed procedure of this control is shown in FIG. block b
First, the deviation ΔX (ΔX
=x-y) (block b1), and determines whether the deviation ΔX is positive, negative, or 0 (block b2).

If the deviation ΔX is negative, the swash plate 6
Block b3) outputs a signal to completely reduce the displacement of a from the output unit 23; if the deviation ΔX is O, outputs a signal to stop the swash plate 6ak; block b4); if the deviation ΔX is positive, the swash plate 6a Outputs a signal that increases the displacement of (
Block b5).

In this way, normal swash plate control is applied to blocks a and b.

Next, the process proceeds to block C shown in FIG.

This block C performs the function of the filter circuit 11 in the previous embodiment, and its details will be explained in the seventh section.
0 shown in the figure. First, in block C1, block b1
The calculated hole deviation ΔX is taken out from the RAM 22, and its absolute value 1ΔX1 is compared with the value ΔXmax. Here, the value ΔXmax is set from the maximum displacement speed of the swash plate 6a and indicates the upper limit value of the hole. Now, if the time required for processing from block a to block b shown in FIG. 5 is t, the rising speed of the operation signal
Since the maximum displacement speed of a is approximately ΔXn1ax/l, in order to suppress the rising speed of the operation signal
It is necessary to compare max and ". This comparison is done in block C1, and in block c1 the absolute value of deviation)
If it is determined that 1iz is less than the upper limit value ΔXrr1ax, the hole operation signal Xk is inputted in block a and used as the operation signal X' for determination (block c2) (also, in block CI, the absolute value of the deviation 1ΔXl exceeds the upper limit value ΔXmax. If it is determined that the upper limit value ΔXmax is exceeded, the upper limit value ΔXmax is set on the swash plate 6 to the judgment operation signal
``!l'' is added in the tilting direction of a and subtracted, and the obtained hole value is used as the current judgment operation signal X' (block c3).

Next, a failure determination of the hydraulic pump 6 is performed (block d in Figure 0!5). The details of the procedure of block d are shown in FIG. In block d, the lower limit judgment value X1 (X = X' - Δ
) and store it in the RAM 22 (block dl). This judgment value X1 corresponds to the subtraction value that is the output of the adder circuit j3d in the previous embodiment. Next, the signal X' and the allowable value Δ are added to obtain the upper limit judgment value X 3 (X 2
=, X/+Δ) and stores it in the tRAM 22 (block d2).

This judgment value X2 is determined by the addition circuit 13a in the awning embodiment.
corresponds to the added value that is the output of . Next, the displacement signal Y and the lower limit determination value X1 stored in the RAM 22 are extracted, and it is determined whether the signal Y is greater than or equal to the determination value X (block d3). If the signal Y is greater than or equal to the judgment value X, block d
Proceed to step 4, this time use the signal Y and the upper limit judgment value X2iR
It is determined whether the signal Y is output from AM2 and is less than or equal to the determination value X2. If the signal Y is less than or equal to the judgment value X2, the process returns to block a and is repeated again. block d3
If it is determined that the signal Y is less than the judgment value X1, then fC'JE
J or in block d4 (if it is determined that the ff number Y exceeds the judgment value Return to step a and repeat the same process.

Note that the failure/lg signal output from the output section 23 can be used to operate a display, an alarm, an emergency stop e'AjR, a failure monitor, etc., as in the previous embodiment. be. The filtering of operation signals is especially important for emergency stop devices.
It is the same as the case of the embodiment that employs JjjL and is effective in large cases.

In this way, in this embodiment, the swash plate is controlled using a microcomputer, filter processing is performed, and the six judgment signals (・■ production A J and displacement No. 45) are used, and this judgment operation signal and the allowable Use this value to determine the lower limit judgment value and upper limit judgment value, compare these judgment values with displacement No. 16, and output a signal to detect a failure when the displacement signal is less than the lower limit judgment value or exceeds the upper limit judgment value. Make the holes as instructed, so
Cut the hydraulic piping! Failure diagnosis of the hydraulic pump can be performed automatically and quickly at all times without having to take the tester apart or remove the tester. Furthermore, since a microcomputer is used, similar processing can be sequentially performed on each of a large number of hydraulic pumps, and failure diagnosis of these hydraulic pumps can be performed simultaneously. Hama et al. also performs filter processing on the operation signal, thereby preventing the generation of temporary failure signals due to delays in tracking of the swash plate, and generating failure signals only in response to steady failures. be able to.

In each of the above embodiments, the operation +-j is explained as a signal issued from the operating lever, but it is not limited to this, and can be used as a command for the final swash plate position to the swash plate drive device. It may be a boost.

As mentioned above, in the present invention, the rate of change is limited to below the maximum displacement rate of the variable displacement mechanism, and the absolute value of the difference between the operation signal for judgment and the displacement signal is compared with a predetermined tolerance value, and the When the absolute value of exceeds the allowable value, No. 6, which indicates a failure, is fully output. Therefore, without disconnecting the hydraulic piping or installing the tester, you can automatically and quickly check the +/c hydraulic pressure. Pump failure diagnosis can be performed,
Furthermore, failure diagnosis of multiple hydraulic pumps can be performed simultaneously. Furthermore, a fault signal can be generated only for steady faults.

[Brief explanation of the drawing]

FIG. 1 is a hydraulic circuit diagram of a conventional hydraulic pump failure diagnosis device, FIG. 2 is a block diagram of a hydraulic pump failure diagnosis device according to a first embodiment of the present invention, and FIGS. 3(a) and (b) )
, (c) is an output characteristic diagram of the comparison circuit and OR circuit shown in FIG. 2, FIG. 4 is a block diagram of a hydraulic pump failure diagnosis device according to the second embodiment of the present invention, and FIGS. 7 and 8 are flowcharts showing the entire operation of the failure diagnosis device shown in FIG. 4. 6... Hydraulic pump, 6a... Swash plate, 7
... Swash plate drive device, 8 ... Displacement meter, 9
. . . Person: h production bar, 11 . . . Filter circuit, 12 . . . Failure determination circuit, 13a. 13b...addition circuit, 14a, 14b...
...Comparator, 15...OR circuit, J7...
...1b:"Control device 11.18...Multiplexer, 19...A,/Dy,,H7-...
73.20...-CPU, 21-Old...ROM, 22
----RAM, 23... Output section. Figure 7 Figure 8

Claims (1)

[Claims] 1. A hydraulic pump equipped with a variable displacement mechanism;
displacement amount command generation means for generating a command value for displacing the displacement displacement variable mechanism by a required amount, detection means for detecting the displacement amount of the displacement displacement variable a'7), and said displacement amount command generation means. A) A limiting means for limiting the rate of change of the output signal of the means to a value equal to or less than the maximum displacement speed of the old #H; a comparison means for comparing the absolute value of the hydraulic pump with a predetermined allowable value; and an output for outputting a failure signal indicating a failure of the hydraulic pump when the comparison means determines that the absolute value exceeds the allowable value. 1. A failure diagnosis device for a hydraulic pump, comprising: means. 2. A failure diagnosis device for a hydraulic pump according to claim 1, wherein the limiting means is a filter circuit. 3. In claim 1, the comparison means:
an addition means for adding the tolerance value to the acupuncture point signal; a subtraction means for subtracting the tolerance value from the acupuncture point signal; a first comparison means for outputting a signal when the addition exceeds the threshold value; and a first comparison means for outputting a signal when the displacement detected by the detection means is less than the value subtracted by the subtraction means. 1. A hydraulic pump failure diagnosis system, characterized in that it is comprised of a second comparison means.