JPH0247691B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for diagnosing failures in rotary hydraulic equipment such as hydraulic pumps and hydraulic motors.

Traditionally, to diagnose failures in rotary hydraulic equipment,
Diagnosers judge vibrations, sounds, temperatures, etc. generated from rotary hydraulic equipment by feeling, so if the diagnostician has little experience or skill, accurate diagnosis cannot be made.

In addition, to diagnose a hydraulic pump failure, detect the relationship between the discharge flow rate and discharge pressure of the hydraulic pump,
A comparison is made with the relationship between the discharge flow rate and the discharge pressure when the hydraulic pump is normal. Furthermore, in order to diagnose a failure of a hydraulic motor, a predetermined load is applied to the hydraulic motor and an ineffective outflow amount is detected. That is, volumetric efficiency (pressure, flow rate) is detected in order to diagnose failures in rotary hydraulic equipment. However, rotary hydraulic equipment exhibits high volumetric efficiency until just before failure occurs, and once signs of failure occur, the volumetric efficiency decreases in a short period of time, leading to failure. This is because even if the components of rotary hydraulic equipment undergo mechanical wear and deterioration, the volumetric efficiency is hardly affected. In particular, in the case of hydraulic pumps, the discharge flow rate can be easily adjusted using the pump regulator, and the discharge pressure can be easily changed using the main relief valve. Even if the volumetric efficiency decreases, it is easy to temporarily restore the volumetric efficiency, making it impossible to diagnose accurately. Furthermore, detecting the volumetric efficiency of rotary hydraulic equipment requires a lot of time and is laborious.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a failure diagnosis device for rotary hydraulic equipment that can accurately perform diagnosis in a short period of time and easily.

In order to achieve this object, the present invention provides a pulsation detection device for detecting hydraulic pulsation during operation of rotary hydraulic equipment, and a pulsation detection device that detects the hydraulic pulsation from the start of rise to the end of fall of the hydraulic pulsation from the output of the pulsation detection device. A calculation device for determining at least one of the width time and the peak pressure of the hydraulic pulsation, and a display device for displaying the value determined by the calculation device are provided.

By the way, in a rotary hydraulic device, the hydraulic pulsation caused by each component is included in the hydraulic pulsation during its operation. Since the peak pressure and vibration frequency of the hydraulic pulsations due to each component are different, the hydraulic pulsation due to a certain component can be separated from the hydraulic pulsation during operation of the rotary hydraulic equipment. Furthermore, as the damage to the component increases, the peak pressure of the hydraulic pulsation due to the component decreases, and the time from the start of the rise to the end of the fall of the hydraulic pulsation due to the component increases, that is, the pulsation width time increases. By determining the peak pressure and pulsation width time of hydraulic pulsation, the degree of failure of the component can be determined.

For example, in a plunger hydraulic pump having m plungers, when the hydraulic pump rotates once, m hydraulic pulsations are generated by the plunger portion. This hydraulic pulsation is separated and a predetermined rotation, for example, n
By determining the peak pressure and pulsation width time of the rotation, and determining the representative peak pressure and representative pulsation width time from these peak pressures and pulsation width times, it is possible to determine the degree of failure of the plunger portion. Furthermore, by determining the representative peak pressure and representative pulsation width time of each plunger from the peak pressure and pulsation width time of each plunger, the degree of failure of each plunger can be determined.

FIG. 1 is a diagram showing a failure diagnosis device for rotary hydraulic equipment according to the present invention. In the figure, 1 is a plunger hydraulic pump having m plungers, 2 is a discharge side pipe of the hydraulic pump 1, 3 is a hydraulic pulsation detector that converts the hydraulic pulsation in the pipe 2 into a voltage change, and 4 is a hydraulic pulsation detection The hydraulic pulsation detector 3 and the amplifier 4 constitute a pulsation detection device. 5 is a separation/filter that extracts voltage changes corresponding to the hydraulic pulsation caused by the plunger section of the hydraulic pump 1 from the output of the amplifier 4; 6 is a representative pulsation width time of the hydraulic pulsation caused by the plunger section from the output of the separation/filter 5; As shown in FIG. 10, the computing unit 6 has a pulsation width time detector 6a, a frequency distribution detector 6b, and a representative pulsation width time detector 6c. Then, the voltage changes output from the separation/filter 5 are as shown in Figs. 2 and 3 (Fig. 2 shows the case when the plunger part is normal, and Fig. 3 shows the case when the plunger part is damaged). In this case, the pulsation width time detector 6a detects the time when the voltage change exceeds the sum of the voltage V _p and the predetermined voltage V _c , that is, the pulsation width time.
Find T ₁₁ , T ₂₁ , ..., T _no , and use the frequency distribution detector 6
b is Fig. 4, Fig. 5 (Fig. 4 is normal, Fig. 5 is normal)
The representative pulsation width time detector 6c determines the frequency distribution of the pulsation width time T ₁₁ as shown in FIG. In addition, a separation/filter 5,
The arithmetic unit 6 constitutes an arithmetic device. 7 is a display device that displays the results determined by the calculator 6;

In this failure diagnosis device, the hydraulic pump 1 is operated with a constant rotation speed and a constant discharge pressure, and in this state, the hydraulic pulsation detector 3 converts the hydraulic pulsation in the conduit 2 into voltage changes. . next,
An amplifier 4 amplifies the output of the hydraulic pulsation detector 3, and a separation/filter 5 extracts a voltage change corresponding to the hydraulic pulsation caused by the plunger section. Next, the pulsation width time detector 6a detects pulsation width times T ₁₁ , , T ₂₁ ,...
..., T _no are determined, the frequency distribution such as the pulsation width time T ₁₁ is determined by the frequency distribution detector 6b, and the representative pulsation width time T is determined by the representative pulsation width time detector 6c. Furthermore, the representative pulsation width time T is displayed on the display device 7.

In the example shown in FIG. 1, the representative pulsation width time T was determined, but the value obtained by subtracting the voltage V _p + V _c from the voltage value of each peak shown in FIGS. 2 and 3, that is, the peak voltage V ₁₁ , V ₂₁ , ..., V _no (corresponding to the peak pressure), then find the frequency distribution of the peak voltage V _11, etc., and then find the peak voltage with the largest number, that is, the representative peak voltage V. good. Furthermore, T ₁₁ , T ₁₂ , ..., T _1o are the pulsation width times caused by the first plunger, T ₂₁ , T ₂₂ , ..., T _2o
is the pulsation width time caused by the second plunger,...
Since T _n1 , T _n2 , .../T _no is the pulsation width time due to the m-th plunger, Figs.
The figure shows a normal case, and Figure 7 shows a damaged case)
As shown in , the frequency distribution of pulsation width times may be determined for each plunger, and representative pulsation width times T ₁ , T ₂ , . . . , T _n may be determined for each plunger. Also,
Similarly, as shown in Figures 8 and 9 (Figure 8 shows the normal case and Figure 9 shows the damaged case), find the frequency distribution of the peak voltage for each plunger, and Typical peak voltage V ₁ ,
V ₂ , ..., V _n may also be determined. Furthermore, if the damage to the plunger becomes large, the typical pulsation width time
T ₁ , T ₁ , ..., T _n , typical peak voltage V, V ₁ , ...
..., the number of V _n, that is, the maximum number N _T , N _T1 , ...,
Since N _Tn , N _v , N _v1 , ..., N _vn decreases,
The maximum number N _T etc. may also be determined. In addition, representative pulsation width time T, etc., representative peak voltage V, etc., maximum number N _T ,
By comprehensively judging N _v etc., the plunger part,
The degree of failure of each plunger may be determined.

Furthermore, although the plunger hydraulic pump has been described in the above-described embodiments, failures can be similarly diagnosed for vane hydraulic pumps and gear hydraulic pumps. In other words, one hydraulic pump
When it rotates, in a vane hydraulic pump, hydraulic pulsations occur according to the number of vanes, and in gear hydraulic pumps, hydraulic pulsations occur according to the number of teeth of the gears, so these hydraulic pulsations cause the vane part, each vane, It is possible to determine the degree of failure of the gear part and each tooth of the gear. In addition, malfunctions of the plunger part of a plunger hydraulic pump include wear of the cylinder part that supports the plunger, wear of the shoe provided between the plunger and the plunger sliding surface, deterioration of the bearing that supports the shaft, and even if it is a variable displacement pump. For example, the main cause is deterioration of the swash plate or the shaft that supports the slant shaft. In addition, failures of the vane part of a vane hydraulic pump include wear of the vane, deterioration of the bearing that supports the vane rotor, wear of the oil leakage prevention plate installed on the side of the vane, and failure of the inside of the housing installed around the outer circumference of the vane. The main cause is wear and tear. Furthermore, in gear hydraulic pumps, wear on the tooth surfaces, deterioration of the bearings that support the pair of gears, wear on the oil leakage prevention plates provided on the sides of the pair of gears, wear on the inside of the housing provided around the outer circumference of the gears, etc. is the main one. Further, in the above-described embodiment, a failure diagnosis device for a hydraulic pump has been described, but failures can be similarly diagnosed for a hydraulic motor as well. In this case, hydraulic pulsations in the discharge side conduit of the hydraulic motor are detected. Furthermore, in the above embodiment, the representative pulsation width time T, T ₁ , etc., representative peak voltage V, V _1, etc., maximum number N, N _1, etc. of the plunger portion, each plunger were determined, but the pulsation width time T ₁₁ ，……，
Average value of T _no , average value of T ₁₁ , T ₁₂ , ..., average value of T _1o , etc.
Peak voltage V ₁₁ , ..., average value of V _no , V ₁₁ , V ₁₂ ,
..., the average value of V _1o, etc. may be determined.

As explained above, in the failure diagnosis device for rotary hydraulic equipment according to the present invention, the hydraulic pulsation of the rotary hydraulic equipment is detected and the failure is diagnosed from this hydraulic pulsation, so that failure can be accurately predicted. Therefore, it is possible to prevent accidents due to malfunctions. Moreover, since failures in rotary hydraulic equipment can be diagnosed simply by attaching the pulsation detection device to the pipe line, the diagnosis can be performed easily and in a short time. As described above, the effects of this invention are remarkable.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a failure diagnosis device for rotary hydraulic equipment according to the present invention, FIGS. 2 and 3 are diagrams showing voltage changes corresponding to hydraulic pulsation due to the plunger portion,
Figures 4 and 5 are diagrams showing the frequency distribution of pulsation width time, Figures 6 and 7 are diagrams showing the frequency distribution of pulsation width time for each plunger, and Figures 8 and 9 are diagrams showing the frequency distribution of pulsation width time for each plunger. A diagram showing the frequency distribution of peak voltage for each,
FIG. 10 is a diagram showing a part of the failure diagnosis apparatus for the rotary hydraulic equipment shown in FIG. 1. 1...Plunger hydraulic pump, 2...Pipeline, 3
...Hydraulic pulsation detector, 4...Amplifier, 5...Separator/filter, 6...Arithmetic unit, 7...Display device.

Claims (1)

[Scope of Claims] 1. A pulsation detection device that detects hydraulic pulsation during operation of a rotary hydraulic device, and from the output of the pulsation detection device, the pulsation width time from the start of rise to the end of fall of the above-mentioned hydraulic pulsation, the above-mentioned 1. A failure diagnosis device for rotary hydraulic equipment, comprising: a calculation device for determining at least one of the peak pressures of hydraulic pulsation; and a display device for displaying the value determined by the calculation device. 2. The failure diagnosis device for rotary hydraulic equipment according to claim 1, wherein the pulsation detection device is one that converts the hydraulic pulsation into a voltage change and amplifies it. 3. The rotary hydraulic system according to claim 1 or 2, wherein the calculation device is one that calculates the frequency distribution of the pulsation width times and calculates the pulsation width time with the largest number of pulsation width times. Equipment failure diagnosis device. 4. The rotary hydraulic equipment according to claim 1 or 2, characterized in that the calculation device is one that calculates the frequency distribution of the peak pressures and calculates the peak pressure with the largest number of peak pressures. Fault diagnosis device.