JP3014560B2 - Diagnosis method of overhaul time of piston pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for diagnosing the overhaul of a piston pump used in various types of machinery such as a construction work machine.

[0002]

2. Description of the Related Art In general,
In this type of machine, a piston pump is sometimes used as a supply source of hydraulic oil (pressure oil).
As with other mechanical devices, such piston pumps wear out as they are used, causing problems such as oil leaks and backlash.They become increasingly large and need to be overhauled. Failure to overlook and continue to use may cause failure. Among such problems, with respect to oil leakage, by measuring the amount of oil leaking into the casing, it is possible to diagnose whether it is time to overhaul. by the way,
As shown in FIG. 1, the piston pump 1 includes a casing 2, a drive shaft (input shaft) 3 that is supported by the casing 2 and receives power from an engine, a swash plate 4 that rotates integrally with the drive shaft 3, A slipper 5 provided on the swash plate 4, a piston 6 whose base end is supported by the slipper 5 in a spherical sliding state, a cylinder tube 7 on which the piston 6 slides, a cylinder tube 7
Is configured using various member devices such as a valve plate 8 provided in the piston pump 1, but when the piston pump 1 is operated,
Wear of the spherical sliding portion between the piston 6 and the slipper 5 is particularly remarkable, and rattling occurs. However, this wear state cannot be observed at all from the appearance of the pump as in the case of the oil leak described above, and cannot be confirmed unless the pump is disassembled. And
If the pump continues to be used with such progress of wear, the wear will eventually exceed the allowable range, causing the piston 6 to come off the slipper 5 or be damaged, causing a sudden failure. However, there is a problem that a lot of trouble and cost are required to repair the one that has led to such a failure.

[0003] Conventionally, there is known a method of diagnosing whether or not the backlash generated in the piston pump has become large and it is necessary to overhaul by detecting the backlash of the piston pump as vibration. I have. However, since the piston pump is mounted on the body (vehicle body), in addition to the vibration of the piston pump itself to be diagnosed, various drive sources and power sources such as an engine, a pump not to be diagnosed, and a hydraulic pump are used. Because the vibration from the source is transmitted, only the vibration of the piston pump to be diagnosed is
It is virtually impossible to detect with the body mounted, and in order to make an accurate diagnosis, the diagnosis must be made by removing the piston pump from the body or stopping the drive of other mechanical devices. There is a problem that it does not. Also,
By comparing the hole diagnostics with normal data
It is advisable to do this, but when doing so
Data is needed, and without it, diagnosis cannot be made.
There is a problem.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in order to provide a method of diagnosing the overhaul timing of a piston pump which can eliminate these disadvantages in view of the above-mentioned circumstances. In diagnosing whether or not the time when the piston pump needs overhaul is reached, a discharge pulsation frequency of discharge oil is detected from a discharge side line of the piston pump, and a waveform observed in the detected pulsation spectrum The peculiar pee of
The higher the frequency, the higher the frequency
When it is time to overhaul
It is characterized by making a diagnosis .

According to the present invention, with this configuration, it is possible to determine whether or not the piston pump requires overhaul while maintaining it mounted on the body and in a normal state .
This enables accurate and reliable diagnosis without the need for data .

[0006]

Next, an embodiment of the present invention will be described with reference to the drawings. In the drawings, reference numeral 1 denotes a piston pump, which is a body of a building machine (not shown).
The drive shaft 3 rotates based on the driving of the engine 9, and the rotation of the swash plate 4 accompanying this causes the plurality of pistons 6 provided in the axial direction of the drive shaft 3 to tilt. The piston operates by rotating through a slipper 5 integrally attached to the plate 4 to suck oil from the tank 10 and discharge the oil. Conventionally, necessary driving such as running driving of a crawler type running device, working driving of a working means such as a boom, turning driving of a turning device, and the like are performed.

Now, the piston pump 1 has a tank 1
A suction line 1a for sucking oil from 0 and a discharge line 1b for discharging oil are provided as oil passages, and a pulsation detection line 1c is formed as a branch in the discharge line 1b as an oil passage. This pulsation detection line 1c
Is usually sealed by a suitable sealing means such as a plug, but is opened when diagnosing whether or not the piston pump 1 requires overhaul, and then the piston pump 1 is opened. A pulsation detector 11 for detecting pulsation of oil discharged to the discharge line 1b can be connected. Incidentally, the pulsation detector 11 does not necessarily need to be connected to the dedicated pulsation detection line 1c as described above, and can be directly connected to the discharge line 1b by removing the coupler of the discharge line 1b. If a dedicated pulsation detection line 1c is provided as in the embodiment, workability can be improved and it is convenient. The pulsation detection result detected by the pulsation detector 11 is amplified by the amplifier 12 and input to the data recording unit 13, analyzed by the frequency analysis unit 14, and printed on recording paper by the recording unit 15 as necessary. You can get out. The pulsation detector 11 used in the embodiment is a general-purpose pulsation detector capable of detecting pulsation in a frequency range from 0 to 2000 Hertz (Hz).

Now, the pulsation of the oil discharged from the piston pump 1 is detected in this manner.
The piston pump 1 is of a variable displacement axial plunger type and has an input rotation speed of 1850 rotations / minute (rpm).
m), when the discharge flow rate is 456 liters / minute (l / m) and the discharge pressure is 690 kilopascals (kPa), this is mounted on a wheel loader having a total weight of approximately 85 tons and is operated. In this case, when each pulsation was detected at the time of a new vehicle, at the time of 6100 hours of operation, and at the time of 8950 hours of operation, the spectrum of the pulsation waveform of the oil discharged from the piston pump 1 was as shown in FIGS. 3, 4, and 5, respectively. (The vertical axis represents the detection voltage (V) and the horizontal axis represents the frequency.) Observing the spectrum of the new vehicle shown in FIG.
At the frequency of Hertz (Hz), there are first-order, second-order, to fifth-order large peaks (singular peaks). These unique peaks are smaller at higher frequencies and tend to be downwardly to the right. It was connected. In contrast, 61
After the operation for 00 hours, the secondary and tertiary (especially tertiary) singular peaks were observed to be significantly increased as shown in FIG. 4, and the singular peaks were generally in a mountain-like state as a whole. . After 8950 hours of operation,
As shown in FIG. 5, the tertiary and quaternary (especially the quaternary) singular peaks increased remarkably, and the singular peaks tended to rise to the right with larger amplitudes as the frequency increased.
On the other hand, when the piston pump was disassembled for each operation time and the wear state of the spherical sliding portion between the slipper 5 and the piston 6 was observed, the one after the operation for 6100 hours was still usable. The time required for overhaul had not yet been reached, and the remaining use time was considerable. However, after 8950 hours of operation, the wear had progressed considerably, and the time required for overhaul had been reached.
When the piston pump 1 after 8950 hours of operation and overhauled was regenerated and the pulsation spectrum of the discharged oil was detected in the same manner, the waveform was substantially the same as that of the new vehicle (not shown). . From this result, as shown in the pattern diagram of FIG. 9, the pulsation waveform is close to a new vehicle or immediately after overhaul in a state of downward slope (solid line state in FIG. 9) based on the primary singular peak. In the tendency state (two-dot chain line state in the figure), there is still a remaining use time, and in the upward tendency state (dashed line state in the figure), it is found that the overhaul is needed. Was. Therefore, in order to further ascertain whether this knowledge is correct or not, in the same manner, for a number of piston pumps of the same type mounted on a construction machine currently operating at the site, the oil discharged from the piston pump 1 is similarly set. And when the piston pump was disassembled as appropriate, the peak with a peculiar peak was not yet at the time when overhaul was necessary, but the one with the upward trend was overhaul. When it is observed that the required time has been reached, and if the singular peak of the pulsation spectrum of the discharged oil is in a state of rising to the right, it should be diagnosed that the time required for overhaul has been reached. Can be.

Next, a variable displacement axial plunger type piston pump having an input rotation speed of 180
At 0 revolutions / minute (rpm), the discharge flow rate is 183 liters / minute (l / m), and the maximum working pressure is 31.4 megapascals (M
For Pa), this was mounted on a hydraulic shovel having a total weight of 18.5 tons and operated, and this was measured immediately after overhaul, and after that, each pulsating spectrum after 1100 hours and 2350 hours of operation was detected. 6, 7 and 8 respectively. Immediately after overhaul, this piston pump 1
Primary, secondary, tertiary and quaternary singular peaks are detected at the frequencies of 50, 675 and 900 Hertz (Hz), but these singular peaks immediately after overhaul have a downward slope of approximately right as shown in FIG. It was in the state, 11
After the operation for 00 hours, the shape became approximately mountain-shaped as shown in FIG. 7, and after 2350 hours, the shape tended to rise rightward as shown in FIG. Further, when these piston pumps 1 after operation were disassembled, when the arrowhead and the shape of the mountain shape were changed, it was still in a state where the overhaul was not yet required and the remaining use time was still present. The time for overhaul has been reached for those that rise to the right, and for this piston pump,
The diagnosis that the overhaul is required is made when the specific peak of the pulsation spectrum of the discharged oil is in a state of rising to the right.

As described above, the diagnosis as to whether or not the piston pump has reached the time required for overhaul is made by judging whether or not the peculiar peak of the pulsation spectrum of the discharge oil tends to rise to the right. for any good, and further it has obtained the arrow-clad same kind of knowledge was confirmed in the same manner as for several other of the piston pump, the method of the present invention means a Rukoto available generically. Further, if the detailed analysis of the pulsation spectrum progresses, the possibility of estimating the remaining use time in the operation process is included, but in any case, by implementing the present invention,
Compare barhole diagnostics with normal data
Without the need for normal data.
Overhaul diagnosis can be performed easily even when there is no By the way, as described above, the amplitude of each next peculiar peak gradually increases with the operation of the piston pump, but the increasing tendency is that the higher the operating time, the larger the high frequency side and the amount of the increase is remarkable. Is observed,
The reason is not always clear, and it is recognized that this is one of the future research topics.
It is presumed that as the abrasion of the spherical sliding portion progresses and the play of the spherical sliding portion increases, more complicated blur occurs in the spherical sliding portion .

[Effects] In summary, since the present invention is constructed as described above, it is determined whether or not the time when the piston pump needs overhaul has been diagnosed as in the prior art. Detects pulsation of discharged oil instead of vibration ,
The peculiar peak observed in the spectrum is high
If there is a tendency to rise to the right as the wave number increases,
To be able to diagnose that the hole has reached the required time
Prepare a basic spectrum
There is no need to make a diagnosis in comparison with this.
Engine and oil using only the spectrum observed at
Be affected by the vibration of other drive sources or power sources such as pressure motors.
As a result, an accurate and reliable diagnosis can be easily performed.

[Brief description of the drawings]

FIG. 1 is a partially cutaway sectional view of a piston pump.

FIG. 2 is a block diagram showing a diagnostic means for overhaul timing.

FIG. 3 is a pulsation spectrum at the time of a new vehicle of the first embodiment.

FIG. 4 is a pulsation spectrum 6100 hours after the first example.

FIG. 5 is a pulsation spectrum 8950 hours after the first example.

FIG. 6 is a pulsation spectrum immediately after overhaul of the second embodiment.

FIG. 7 is a pulsation spectrum 1100 hours after the second example.

FIG. 8 is a pulsation spectrum at 2350 hours after the second example.

FIG. 9 is a pattern diagram of a pulsation spectrum of a piston pump.

[Explanation of symbols]

 Reference Signs List 1 piston pump 1a discharge line 1b supply line 1c pulsation detection line 4 swash plate 5 slipper 6 piston 11 pulsation detector

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-49-30901 (JP, A) JP-A-3-260404 (JP, A) JP-A-1-125876 (JP, U) 47691 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) F04B 39/00 F04B 1/20 F04B 49/10 F04B 51/00 F04B 53/00

Claims (1)

(57) [Claims] When diagnosing whether or not a time when a piston pump needs overhaul has been reached,
When the discharge pulsation frequency of the discharge oil is detected from the discharge side line of the piston pump, and the singular peak of the waveform observed in the detected pulsation spectrum is in a state of rising to the higher right as the frequency is higher, it is detected. A method for diagnosing the overhaul timing of a piston pump, characterized in that the overhaul is diagnosed as having reached a required time.