JP2022026260A - Machine lubrication oil supply system monitoring method and device - Google Patents

Abstract

To provide a machine lubrication oil supply system monitoring method and device capable of monitoring a supply state of a lubrication oil of a lubrication oil supply system using a constant capacity pump of a machine with high accuracy.SOLUTION: According to the present invention, a machine lubrication oil supply system monitoring method and device for monitoring a supply state of a lubrication oil of a lubrication oil supply system using a constant capacity pump for supplying the lubrication oil to each part of a machine includes a pressure information acquisition unit 6 for acquiring pressure related information related to the pressure of the lubrication oil, and a temperature information acquisition unit 5 for acquiring temperature related information related to the temperature of the lubrication oil, acquires an actual temperature of the lubrication oil on the basis of the temperature related information from the temperature information acquisition unit 5, acquires appropriate oil pressure that should be generated at the actual temperature of the lubrication oil by arithmetic operation, also acquires actual pressure of the lubrication oil on the basis of the pressure related information from the pressure information acquisition unit 6, and monitors a supply state of the lubrication oil of the lubrication oil supply system while comparing the actual pressure of the lubrication oil with the appropriate oil pressure.SELECTED DRAWING: Figure 3

Description

The present invention relates to a technique for monitoring the supply state of lubricating oil in a lubricating oil supply system using a constant capacity pump of a machine in general.

Conventionally, in a lubricating oil supply system that uses a constant-capacity pump to supply lubricating oil to each part of a machine in general (for example, a press machine or other machine tool, a general machine such as an internal combustion engine), the lubricating oil has been used. Lubricating oil, such as monitoring the supply status of the machine, stopping the operation of the machine (for example, stopping the interlock) if there is an abnormality, and encouraging measures to avoid the abnormal condition of the machine. There is a need for a monitoring system that can contribute to the maintenance and management of the supply system.

Here, one of the commonly used methods for monitoring that the lubricating oil supply system using the machine's constant-capacity pump is supplying lubricating oil normally is to turn it on at a predetermined hydraulic pressure or higher. It is a method of monitoring that hydraulic pressure is generated by using a pressure switch.

However, the higher the oil temperature of the lubricating oil, the smaller the viscous resistance, and therefore the lower the hydraulic pressure. Therefore, in the case of the method of monitoring using a pressure switch, the set value of the pressure (setting lower limit hydraulic pressure) at which the pressure switch is turned on for abnormality detection in the temperature range (normal time) in which the lubricating oil supply system is operated ) Should be set lower than the normal oil pressure that occurs at the highest oil temperature.

On the other hand, when the oil temperature drops, the hydraulic pressure generated at that time and the lower limit setting hydraulic pressure of the pressure switch deviate greatly, so it is difficult to detect even if the lubricating oil supply system is damaged or clogged. There is.

Japanese Unexamined Patent Publication No. 3-285800

Further, a flow meter may be used as a method for monitoring the lubricating oil supply system (for example, Patent Document 1). In this case, the flow rate of the lubricating oil supplied from the constant-capacity pump is constant, so the effect of temperature is small. Therefore, the flow rate to be monitored can be set appropriately in the temperature range in which the lubricating oil supply system is operated.
However, even if there is a shortage of lubricating oil supply due to an abnormality such as outflow or clogging of the lubricating oil due to damage to the tributary pipe on the secondary side of the flow meter in the lubricating oil supply system, the flow rate does not change. It cannot be detected. There is also a method of attaching multiple flow meters to the end of the required refueling section for monitoring, but there is a fact that damage to the piping on the secondary side of the flow meter cannot be detected and the cost increases.

The present invention has been made in view of the above-mentioned circumstances, and has a relatively simple and low-cost configuration, but accurately monitors the supply state of lubricating oil in a lubricating oil supply system using a machine's constant-capacity pump. It is an object of the present invention to provide a method and a device for monitoring a lubricating oil supply system of a machine which can be used.

Therefore, the method for monitoring the lubricating oil supply system of the machine according to the present invention is
A method for monitoring the lubricating oil supply system of a machine that monitors the supply status of the lubricating oil in the lubricating oil supply system that uses a constant-capacity pump to supply lubricating oil to each part of the machine.
A pressure information acquisition unit that acquires pressure-related information related to the pressure of the lubricating oil in the lubricating oil supply system,
A temperature information acquisition unit that acquires temperature-related information related to the temperature of the lubricating oil in the lubricating oil supply system, and
Equipped with
The actual temperature of the lubricating oil is acquired based on the temperature-related information from the temperature information acquisition unit, the appropriate hydraulic pressure to be generated at the actual lubricating oil temperature is acquired by calculation, and the pressure information acquisition unit is used. Obtaining the actual lubricating oil pressure based on the pressure-related information from, and monitoring the lubricating oil supply status of the lubricating oil supply system while comparing the actual lubricating oil pressure with the proper hydraulic pressure. It is a feature.

Further, the lubricating oil supply system monitoring device for the machine according to the present invention is
A machine's lubricating oil supply system monitoring device that monitors the lubricating oil supply status of the lubricating oil supply system that uses a constant-capacity pump to supply lubricating oil to each part of the machine.
A pressure information acquisition unit that acquires pressure-related information related to the pressure of the lubricating oil in the lubricating oil supply system,
A temperature information acquisition unit that acquires temperature-related information related to the temperature of the lubricating oil in the lubricating oil supply system, and
With
The actual lubricating oil temperature is acquired based on the temperature-related information from the temperature information acquisition unit, and the appropriate hydraulic pressure to be generated at the actual lubricating oil temperature is acquired by calculation, and the pressure information acquisition unit is used. Lubricating oil that obtains the actual lubricating oil pressure based on the pressure-related information from, and monitors the lubricating oil supply status of the lubricating oil supply system while comparing the actual lubricating oil pressure with the proper hydraulic pressure. Supply system monitoring and control device,
It is characterized by being configured with.

In the present invention
The proper hydraulic pressure is
When this lubricating oil supply system is a single circular tube, the actual lubricating oil pressure at the temperature of any lubricating oil, the kinematic viscosity of the lubricating oil at the temperature of the arbitrary lubricating oil, and the density of the lubricating oil , The piping resistance coefficient obtained by calculation based on the flow rate of lubricating oil,
The kinematic viscosity of the lubricating oil at the actual temperature of the lubricating oil,
It can be characterized by acquiring based on.

In the present invention
The pipe resistance coefficient is the actual pressure of the lubricating oil at the temperature of the arbitrary lubricating oil, the kinematic viscosity of the lubricating oil at the temperature of the arbitrary lubricating oil, the density of the lubricating oil, the flow rate of the lubricating oil, and the said. It can be obtained by calculation based on the lift of the lubricating oil supply system.

In the present invention
The comparison between the actual pressure of the lubricating oil and the appropriate hydraulic pressure is characterized by comparing the upper and lower limit monitoring values set based on the appropriate hydraulic pressure with the actual pressure of the lubricating oil. Can be.

In the present invention
The pipe resistance coefficient is
Piping resistance coefficient C = ΔP / (ν × γ × Q)
Q: Lubricating oil flow rate (cm ³ / sec)
ΔP: Actual lubricating oil pressure (pressure loss) (MPa)
ν: Dynamic viscosity of lubricating oil (cm ² / sec: St)
γ: Lubricating oil density (kg / cm ³ )
It can be characterized by being obtained by the following formula.

In the present invention
The pipe resistance coefficient is
Piping resistance coefficient C = (ΔP－h × γ × g × 10 ^-4 ) / (ν × γ × Q)
Q: Lubricating oil flow rate (cm ³ / sec)
h: Lift (cm)
g: Gravity acceleration (g = 980cm / sec ² )
ΔP: Actual lubricating oil pressure (pressure loss) (MPa)
ν: Dynamic viscosity of lubricating oil (cm ² / sec: St)
γ: Lubricating oil density (kg / cm ³ )
It can be characterized by being obtained by the following formula.

According to the present invention, the lubricating oil supply of a machine capable of accurately monitoring the supply state of the lubricating oil of the lubricating oil supply system using the constant capacity pump of the machine while having a relatively simple and low cost configuration. A system monitoring method and an apparatus can be provided.

It is a block diagram which shows the whole structure of the lubricating oil supply system monitoring apparatus which concerns on one Embodiment of this invention. It is a flowchart which shows an example of the control which acquires the pipe resistance coefficient C by calculation performed by the lubricating oil supply system monitoring apparatus which concerns on each embodiment. It is a flowchart explaining an example of the monitoring control of the lubricating oil supply system performed by the lubricating oil supply system monitoring apparatus which concerns on each embodiment. It is a figure which shows an example of the pressure curve of the lubricating oil of a machine with respect to the lubricating oil temperature, and the upper and lower limit monitoring value curves (horizontal axis: lubricating oil temperature, vertical axis: lubricating oil pressure). It is a schematic diagram explaining each element which controls the flow of lubricating oil. It is a figure which shows an example of the relationship between the oil temperature of a lubricating oil and the kinematic viscosity (horizontal axis: oil temperature, vertical axis: kinematic viscosity). It is a figure which shows an example of the relationship between the lubricating oil temperature and the lubricating hydraulic pressure of a press machine (horizontal axis: lubricating oil temperature, vertical axis: lubricating hydraulic pressure).

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. The present invention is not limited to the embodiments described below.

The lubricating oil supply system monitoring device according to the embodiment of the present invention monitors the presence or absence of abnormalities in the lubricating oil supply state in the lubricating oil supply system that uses a constant capacity pump to circulate and supply oil to each part of the machine. To obtain pressure information from a pressure sensor or the like that can measure the actual lubricating oil pressure (hereinafter, also referred to as lubricating oil hydraulic pressure, or simply lubricating oil pressure or hydraulic pressure) and output the measured value as an electrical signal. The temperature of a temperature sensor or the like equipped with a unit and capable of measuring the temperature of the lubricating oil (hereinafter, also referred to as the lubricating oil temperature, or simply the lubricating oil temperature or the oil temperature) and outputting the measured value as an electric signal. It includes an information acquisition unit and includes a system capable of sending each signal to a control device having an arithmetic function. Here, the measured actual pressure of the lubricating oil and the theoretical value (appropriate hydraulic pressure) of the hydraulic pressure obtained by the calculation described later are the pressure loss in the lubrication supply system. Pressure loss is the resistance when lubricating oil flows through the piping system of the lubricating oil supply system (friction resistance between the inner wall surface of the piping and the lubricating oil, resistance due to throttle or bending, and flow turbulence (vortex or turbulence). ) Is the energy loss due to), which is indicated by the differential pressure between the inlet (primary side pressure) and the outlet (secondary side pressure) of the piping system, and is also the discharge pressure of the pump.

As a specific example of the lubricating oil supply system monitoring device 100 according to the present embodiment, it is configured as shown in FIG. The base end portion 10A on the upstream side (hereinafter, also simply referred to as the upstream side) of the lubricating oil flow of the lubricating oil passage 10 is configured to include the lubricating oil passage 10 connecting the lubrication destinations 1 to n, and is the lubricating oil storage portion 11. It is installed at a predetermined height with respect to the bottom and is in a state of being immersed in the stored lubricating oil.
Reference numeral 1 in FIG. 1 is a globe valve (ball-shaped valve) that opens and closes the flow path of the passing lubricating oil.

In the lubricating oil passage 10 on the downstream side (hereinafter, also simply referred to as the downstream side) of the lubricating oil flow of the lubricating oil storage unit 11, a globe valve 1, an oil filter 2, an oil pump 3, an oil filter 4, and a temperature information acquisition unit are used. Lubricating oil temperature sensor (hereinafter, also simply referred to as temperature sensor) 5, Lubricating oil pressure sensor as pressure information acquisition unit (hereinafter, simply referred to as pressure sensor) 6, Pressure gauge 7 (for example, visual gauge), Check valve ( The one-way valve) 8 and the orifice 9 (for example, oil supply destinations 1 to n of a bearing or the like) are interposed in this order from the lubricating oil flow upstream side to the lubricating oil flow downstream side.

The control device 20 that controls the lubricating oil supply system monitoring device 100 according to the present embodiment includes the discharge flow rate of the oil pump 3, the electrical signal of the measured value of the lubricating oil temperature from the temperature sensor 5, and the pressure. An electrical signal or the like of the measured value of the lubricating oil from the sensor 6 is input. Although the discharge flow rate of the oil pump 3 can use a value determined according to the pump rotation speed or the like, a flow meter may be provided and the measured value may be used.
Here, the control device 20 according to the present embodiment corresponds to the lubricating oil supply system monitoring control device according to the present invention.

The control device 20 is configured to include various interfaces, A / D converters, various memories, CPUs, etc., and can perform various information input / output, various arithmetic processing, execution of various programs, and the like. It is configured.

Here, as the operation of the lubricating oil supply system according to the present embodiment, when the oil pump 3 is driven predeterminedly by an oil pump drive control device (not shown), the lubricating oil in the lubricating oil storage portion 11 passes through the lubricating oil passage 10. It is sucked up through the oil and sucked into the oil pump 3 via the oil filter 2 on the upstream side. The sucked lubricating oil is pressurized by the oil pump 3 and discharged to the downstream side of the oil pump 3. The control device 20 may also serve as the oil pump drive control device. Further, as the oil pump 3, a constant capacity pump is adopted.

Here, the constant-capacity pump is a pump in which the theoretical discharge flow rate per rotation is fixed to a predetermined value when the pump drive shaft rotates, and is any type such as a gear pump and a vane pump. However, any fixed-capacity pump can be used.

The lubricating oil sucked in and discharged from the lubricating oil storage unit 11 by the oil pump 3 passes through the oil filter 4 on the downstream side, and is interposed in the lubricating oil passage 10, the temperature sensor 5, the pressure sensor 6, and the pressure gauge. 7. After passing through the check valve 8, the oil is supplied to the orifice 9.
The lubricating oil supplied to the orifice 9 is configured to be recovered to the lubricating oil storage unit 11 after being supplied to each of the lubrication destinations 1 to n such as bearings.

In the lubricating oil supply system as described above, the lubricating oil supply system monitoring device 100 monitors whether or not the lubricating oil is normally supplied as follows.

The control device 20 of the lubricating oil supply system monitoring device 100 measures the hydraulic pressure of the lubricating oil supply system at an arbitrary lubricating oil temperature, and obtains the piping resistance coefficient C of the lubricating oil supply system from the measured value by calculation. .. Then, based on this piping resistance coefficient C and the kinematic viscosity at the temperature of the arbitrary lubricating oil obtained from the relationship between the temperature and the kinematic viscosity of the lubricating oil used, the entire operating temperature range of the lubricating oil supply system is reached. It is configured to obtain the proper lubrication by calculation.

Further, the control device 20 acquires "appropriate hydraulic pressure (appropriate hydraulic pressure) in the lubricating oil supply system" for the actual oil temperature acquired based on the electric signal of the measured value of the temperature sensor 5 by calculation, and obtains the "appropriate hydraulic pressure (appropriate hydraulic pressure)". The upper limit oil pressure monitoring value and the lower limit oil pressure monitoring value for detecting an abnormality are automatically set based on the appropriate oil pressure and the allowable range of the upper limit side and the lower limit side of the oil pressure for detecting a preset abnormality. Set.

Then, the control device 20 of the lubricating oil supply system monitoring device 100 monitors the actual oil pressure acquired based on the electric signal of the measured value from the pressure sensor 6, and the measured value of the oil pressure of the lubricating oil is the above-mentioned. When the range of the upper limit hydraulic pressure monitoring value or the lower limit hydraulic pressure monitoring value is exceeded, an abnormality display can be displayed to warn or the machine can be stopped.

For example, in a state where the piping system of the lubricating oil supply system is damaged and the lubricating oil cannot be supplied to a predetermined lubrication point (here, for example, an orifice 9 (for example, a lubrication destination 1 to n such as a bearing)). Since the hydraulic pressure is lowered by reducing the pressure loss, it is possible to detect an abnormality related to such damage based on the lower limit hydraulic pressure monitoring value (lower limit set value) set according to the actual temperature.

On the other hand, when the piping system of the lubricating oil supply system is clogged and the lubricating oil cannot be supplied to the specified lubrication points, the hydraulic pressure rises due to the increase in pressure loss, so it depends on the actual temperature. Based on the set upper limit oil pressure monitoring value (upper limit set value), it is possible to detect an abnormality related to such clogging.

Here, the control for monitoring the supply state of the lubricating oil performed by the control device 20 of the lubricating oil supply system monitoring device 100 will be described in more detail with reference to the flowcharts of FIGS. 2 and 3.
The symbols used in FIGS. 2 and 3 are listed.
Q: Pump discharge flow rate
h: Lift
g: Gravity acceleration
tb: Measured oil temperature ΔPb when calculating the pipe resistance coefficient C: Measured lubrication oil at oil temperature tb νb: Dynamic viscosity of lubricating oil at oil temperature tb γ: Density of lubricating oil to be used
C: Piping resistance coefficient t: Lubricating oil temperature when monitoring the lubricating oil supply system ΔP: Lubricating oil pressure when monitoring the lubricating oil supply system ΔPc: The theoretical value of the lubricating oil at the lubricating oil temperature t (appropriate hydraulic pressure)
ΔPl: Lower limit set value of lubricating oil pressure at lubricating oil temperature t ΔPu: Upper limit set value of lubricating oil pressure at lubricating oil temperature t

FIG. 2 is a flowchart for acquiring the pipe resistance coefficient C. It should be noted that the flow can be executed at a predetermined timing, for example, in a state where the oil pump is operated and the oil pressure and the oil temperature are stable during the operation of the machine.
In step 1 of FIG. 2 (referred to as S in the figure; the same applies hereinafter) 1, the actual oil pressure ΔPb of the lubricating oil is acquired based on the electrical signal from the pressure sensor 6.

In step 2, the actual lubricating oil temperature tb of the lubricating oil is acquired based on the electric signal from the temperature sensor 5.

In step 3, values and constants input by the operator or stored in the memory in advance (pump discharge flow rate Q, kinematic viscosity νb of lubricating oil at lubricating oil temperature tb, density γ of lubricating oil, lift h, gravity acceleration g) Etc.), and based on the actual lubricating oil pressure ΔPb acquired in step 1 and the actual lubricating oil temperature tb acquired in step 2, the piping resistance coefficient C is acquired by calculation. Although the pump discharge flow rate Q can use a value determined according to the pump rotation speed or the like, it is also possible to use a value measured by a flow meter (not shown).

In the following step 4, the pipe resistance coefficient C is stored in the memory, and this flow ends.

The piping resistance coefficient C is a unique value that depends on the configuration of the lubricating oil supply system regardless of the state of the lubricating oil (temperature and kinematic viscosity). Even if the type of oil or operating condition is changed, it is not necessary to acquire it again. However, when the machine is restarted, it is possible to execute the flow of FIG. 2 every time the machine is restarted and acquire the flow each time.

Here, in the present embodiment, the pipe resistance coefficient C is acquired by calculation by the following method, and the appropriate hydraulic pressure in the lubricating oil supply system is acquired by calculation based on the acquired pipe resistance coefficient C.
That is, "a method of estimating the hydraulic pressure in the lubricating oil supply system based on the piping resistance coefficient C acquired by calculation" performed by the control device 20 of the lubricating oil supply system monitoring device 100 according to the present embodiment will be described.

<Lubricant pressure loss determinant>
The pressure loss of the lubricating oil is mainly determined by the following factors.
(A) Lubricating oil discharge flow rate: Q
(B) Dynamic viscosity of lubricating oil: ν
(C) Piping system resistance (pipe resistance coefficient: C)
The pipe resistance coefficient C, which represents the pipe resistance of the lubricating oil supply system, can be calculated and obtained from the following pressure loss equation based on the measured value.

<Basic formula of lubricating oil flow element and pressure loss>
Each element that governs the flow of lubricating oil is defined as shown in FIG.
The general flow of lubricating oil is often laminar. The pressure loss of the laminar flow can be obtained by the equation (1).
The first item of the formula (1) represents the pressure loss in the circular pipe, and the second item shows the pressure due to the head.
ΔP ＝ (128 × ν × γ × L × Q) / (π × d ⁴ × 10 ⁴ ) ＋ h × γ × g ・ ・ ・ (1)
ΔP: Pressure loss (MPa) ν: Hydraulic viscosity of oil (cm ² / sec: St)
γ: Oil density (kg / cm ³ ) L: Pipe length (cm)
d: Pipe inner diameter (cm) Q: Flow rate (cm ³ / sec)
h: Lift (cm) g: Gravity acceleration (g = 980cm / sec ² )
t: Oil temperature (° C)
Here, the pressure due to the lift in the formula (1) may be omitted because the ratio to the pressure loss of the entire lubricating oil supply system is usually small. In this case, ΔP can be obtained by Eq. (1-1).
ΔP ＝ (128 × ν × γ × L × Q) / (π × d ⁴ × 10 ⁴ ) ・ ・ ・ (1-1)
Further, the pressure loss ΔP indicates the differential pressure between the primary side pressure P ₀ and the secondary side pressure P ₁ in FIG. 5, and is generally based on the atmospheric pressure (“P ₁ ” = atmospheric pressure), so that the pressure sensor Can be the measured value of (P ₀ in FIG. 5) (ΔP = “P ₀ + P ₁ ”-“P ₁ ”). However, when atmospheric pressure is not treated as a reference, as shown in FIG. 5, ΔP is changed from “pressure measured by a pressure sensor” (P ₀ in FIG. 5) to “reference pressure” (P ₁ in FIG. 5). Can be the value obtained by subtracting.

<Piping resistance coefficient>
Although the pressure loss of each pipe can be calculated by the equation (1), it is not easy to calculate the pressure loss of the entire lubricating oil supply system. Therefore, in the present invention, the entire lubricating oil supply system is regarded as one pipe, and a model of the entire lubricating oil supply system composed of a plurality of individual pipes is constructed by using the equation (1).

Here, the elements constituting the equation (1) are considered separately as an item peculiar to piping and an item peculiar to lubricating oil.
Piping-specific items and constants: L, d
Lubricating oil-specific items: ν, γ, Q
In order to decompose the equation (1) into a factor due to the piping system and a factor due to the lubricating oil, the items and constants specific to the piping are summarized as the piping resistance coefficient: C, and the one extracted from the first item of the equation (1) is the equation (1). Shown in 2).
C = (128 × L) / (π × d ⁴ × 10 ⁴ ) ・ ・ ・ (2)
Returning the pipe resistance coefficient C to equation (1), ΔP = C × ν × γ × Q + h × γ × g × 10 ^-4 ... (3)
Transformed
C = (ΔP－h × γ × g × 10 ^-4 ) / (ν × γ × Q) ・ ・ ・ (4)
Here, the pipe resistance coefficient when the pressure due to the head is omitted can be obtained by the equation (4-1).
C = ΔP / (ν × γ × Q) ・ ・ ・ (4-1)

Substituting each numerical value (measured oil pressure of lubricating oil, lift, kinematic viscosity of lubricating oil based on measured oil temperature, density of lubricating oil) in the actual lubricating oil supply system into equation (4), the piping resistance coefficient C Can be calculated. The density of the oil in the formula (4) changes according to the oil temperature like the kinematic viscosity of the oil, but the rate of change is smaller than the kinematic viscosity and the influence on the calculation result is small. Therefore, the value assigned to the equation (4) does not necessarily have to be a value based on the measured oil temperature, and may be a general value.

The following is an example in which the pipe resistance coefficient C is calculated by actually substituting a specific numerical value into the equation (4). The pipe resistance coefficient C calculated here is just a numerical model of the actual lubricating oil supply system.
Here, the calculation is performed by inputting the specific numerical values measured in the lubricating oil supply system of a certain press machine.
a) Oil temperature: t = 21 ° C
b) Lubricating oil used: ISO VG32 (general hydraulic oil with kinematic viscosity of 32cSt at an oil temperature of 40 ° C)
c) Oil kinematic viscosity (when the oil temperature is 21 ° C and ISO VG32): ν = 87.5cSt = 0.875 St (cm ² / sec) (from the oil temperature-kinematic viscosity diagram in Fig. 6)
d) Oil density: γ = 0.87 × 10 ^-3 kg / cm ³
e) Pump discharge flow rate: Q = 15.0L / min = 250 cm ³ / sec
f) Maximum pump discharge pressure: Pmax = 2.5 MPa (pump specifications)
g) Pump discharge pressure: ΔP = 0.89 MPa
h) Outer diameter of discharge pipe: d = φ12.7mm
i) Lift: h = 370cm
j) Gravity acceleration: g = 980cm / sec ²
C = (ΔP－h × γ × g × 10 ^-4 ) / (ν × γ × Q)
= (0.89-370 x 0.87 x 10 ^-3 x 980 x 10 ^-4 ) / (0.875 x 0.87 x 10 ^-3 x 250) = 4.511 ・ ・ ・ (5)

As shown in the above calculation result (5), the pipe resistance coefficient C can be calculated, and various things can be simulated using the equation (3).
For example, if the temperature of the oil flowing in the piping system changes, the relationship between the temperature and the kinematic viscosity can be investigated (see, for example, FIG. 6), and the data for each temperature can be input to the formula (3). , It is possible to simulate the hydraulic pressure at each oil temperature. Similarly, the hydraulic pressure generated when the flow rate and kinematic viscosity (oil count) of the oil flowing through the piping system is changed can be simulated.

Here, the state of the in-pipe flow at an oil temperature of 40 ° C of the specific lubricating oil system described above is confirmed.
V: Flow velocity in the pipe (m / sec)
V ＝ (4 × Q) / (π × d ² ) ＝ (4 × 2.5 × 10 ^-4 ) / (π × (12.7 × 10 ^-3 ) ² ) ＝ 1.973 m / sec
ν: Hydraulic viscosity of oil (cm ² / s: St) ISO VG32 (40 ° C): ν ＝ 32cSt ＝ 32 × 10 ^-6 m ² / sec
d: Discharge pipe inner diameter (m): d = φ12.7 mm = φ12.7 × 10 ^-3 m
Q: Flow rate (m ³ / sec): Q = 15.0 L / min = 2.5 × 10 ^-4 m ³ / sec
Reynolds number: Re ＝ (V × d) / ν
= (4 × Q) / (π × d × ν)
= (1.973 × 12.7 × 10 ^-3 ) / (32 × 10 ^-6 )
= 783 ≤ 2000 (laminar flow) ・ ・ ・ (6)
From the above calculation result (6), it can be judged that this example is a laminar flow because the Reynolds number is smaller than 2000.
Therefore, the equation (1) premised on laminar flow holds.

<Characteristics of oil temperature and hydraulic pressure of lubricating oil supply system>
Here, a simulation will be performed on the oil temperature and hydraulic pressure of the lubricating oil supply system based on the specific example exemplified in the above-mentioned <Piping resistance coefficient>.
First, in order to calculate the hydraulic pressure at each temperature, the calculation result (5) is substituted into the equation (3).
ΔP ＝ 4.511 × ν × γ × Q ＋ h × γ × g × 10 ^-4・ ・ ・ (7)
Further, when the numerical values of oil density: γ, flow rate: Q, head: h, and gravity acceleration: g are entered in the equation (7), the equation (8) is obtained, and the hydraulic pressure becomes a function of the kinematic viscosity.
ΔP ＝ 4.511 × ν × 0.87 × 10 ^-3 × 250 ＋ 370 × 0.87 × 10 ^-3 × 980 × 10 ^-4・ ・ ・ (8)

On the other hand, the relationship between the oil temperature and the kinematic viscosity of the lubricating oil ISO VG32 can be approximately expressed as Eq. (9) (see FIG. 6).
ν ＝ 39000 × (t ＋ 19) ^{-ABS (0.0035 × t + 1.58)} (cSt) ・ ・ ・ (9)
Substituting the equation (9) into the equation (8) gives the following equation (10), and as shown in FIG. 7, the pressure loss ΔP is a function of the oil temperature t.
ΔP (ΔPc) ＝ 4.511 × 39000 × (t ＋ 19) ^{-ABS (0.0035 × t + 1.58)} ) × 0.87 × 10 ^-3 × 250
＋370 × 0.87 × 10 ^-3 × 980 × 10 ^-4 (MPa) ・ ・ ・ (10)

In this way, when the piping resistance coefficient C is obtained based on the measured value and the piping system of the actual lubricating oil supply system is modeled, when the oil temperature changes in the lubricating oil supply system or the kinematic viscosity of the oil (oil). It can be obtained as the hydraulic pressure ΔP of the lubricating oil when the count) and the flow rate are changed, that is, the theoretical value ΔPc of the hydraulic pressure at a certain oil temperature of the lubricating oil used. This theoretical value ΔPc is the proper hydraulic pressure obtained when the lubricating oil supply system is normal.

In the present embodiment, based on such an idea, the appropriate hydraulic pressure of the lubricating oil supply system at the actual oil temperature is acquired, and the allowable range of the upper limit side and the lower limit side of the hydraulic pressure set based on the acquired appropriate hydraulic pressure is obtained. Monitor the supply status of the lubricating oil in the lubricating oil supply system based on (the range from the upper limit to the lower limit) and the actual oil pressure. By monitoring the supply status of the lubricating oil in the lubricating oil supply system, it is possible to detect the presence or absence of an abnormality, and if there is an abnormality, an abnormality display is displayed to warn or the machine is stopped. be able to.

Here, an example of monitoring control of the lubricating oil supply system performed by the control device 20 of the lubricating oil supply system monitoring device 100 according to the present embodiment will be described with reference to the flowchart shown in FIG. It should be noted that the flow can be executed, for example, in a state where the oil pump is operated and the hydraulic pressure and the oil temperature are predeterminedly stable during the operation of the machine.

In step 11, the pipe resistance coefficient C acquired in the flowchart of FIG. 2 and stored in the memory is read out.

In step 12, the actual lubricating oil temperature t at present is acquired based on the signal from the temperature sensor 5.

In step 13, the appropriate oil pressure ΔPc corresponding to the current actual lubricating oil temperature t obtained from the temperature sensor 5 is calculated (see equation (10)).
Since the piping resistance coefficient C and the specifications (kinematic viscosity) of the lubricating oil used have been determined, the appropriate hydraulic pressure ΔPc for an arbitrary temperature t can be obtained by calculation using the equation (10). Create a relationship (table) between the lubricating oil temperature and the lubricating oil pressure as shown in the curve T of 4, and obtain the appropriate oil pressure ΔPc according to the actual lubricating oil temperature t at present by referring to the table. You can also do it.

In step 14, the setting lower limit value (ΔPl) of the appropriate hydraulic pressure range at the lubricating oil temperature t is calculated.
The lower limit of setting (ΔPl) can be set by a calculation formula such as, for example, the lower limit of discharge pressure (-15%) (= appropriate hydraulic pressure ΔPc × 0.85) (the lower limit of setting (ΔPl) is shown in FIG. 4). Corresponds to the shown curve L). However, it is not limited to -15%.
In this calculation formula, it is also possible to select in step 14A what percentage below the appropriate hydraulic pressure the set lower limit value (lower limit monitoring value) is set.

In step 15, the setting upper limit value (ΔPu) of the appropriate hydraulic pressure range at the lubricating oil temperature t is calculated.
The set upper limit value (ΔPu) can be set by a calculation formula such as, for example, a discharge pressure upper limit value (+ 15%) (= appropriate hydraulic pressure ΔPc × 1.15) (the set upper limit value (ΔPu) is shown in FIG. 4). Corresponds to the curve U). However, it is not limited to + 15%.
In this calculation formula, it is also possible to select in step 15A what percentage above the appropriate hydraulic pressure the set upper limit value (upper limit monitoring value) is set.

In step 16, the current actual oil pressure ΔP is acquired based on the signal from the oil pressure sensor 6.

In step 17, it is monitored and determined whether or not the set lower limit value (ΔPl) ≤ the current actual oil pressure ΔP ≤ the set upper limit value (ΔPu), and if it is True (or Yes), the process proceeds to step 18 and False. If (or No), the process proceeds to step 19.

In step 18, since the actual hydraulic pressure ΔP at present is within a predetermined range, it is determined that the lubricating oil supply system is normal.

On the other hand, in step 19, since the actual hydraulic pressure ΔP at present is not within the predetermined range, it is determined that an abnormality has occurred in the lubricating oil supply system.

When "setting lower limit value (ΔPl)> current actual hydraulic pressure ΔP", for example, the piping system of the lubricating oil supply system is damaged and the lubricating oil is supplied to a predetermined lubrication point. It is possible to configure the configuration to have an abnormality diagnosis function that determines that the state has disappeared, identifies the failure type, and outputs the determination result, such as "abnormality related to damage to the lubricating oil supply system".
Then, when "current actual oil pressure ΔP> set upper limit value (ΔPu)", the piping system of the lubricating oil supply system is clogged and the lubricating oil is not supplied to the predetermined lubrication point. It is possible to configure a configuration having an abnormality diagnosis function of determining a state and outputting a determination result by specifying a failure type such as "abnormality related to clogging of the lubricating oil supply system".

In step 20, since it is determined that there is an abnormality, an abnormality display is displayed to alert the operator, and control is performed to stop the operation of the machine. The abnormality display includes a warning display such as a character, a warning light or the like that alerts the user through sight, or a warning sound or the like that alerts the user through hearing.

In step 21, it is determined whether or not to continue the monitoring and control of the lubricating oil supply system.
If Yes, return to step 12. If No, this flowchart ends.

As described above, according to the hydraulic oil supply system monitoring device 100 according to the present embodiment, the actual hydraulic oil supply system is modeled by using the pipe resistance coefficient C acquired based on the measured value. Estimate (acquire) the appropriate hydraulic pressure (hydraulic pressure obtained under normal conditions (theoretical value: ΔPc)) according to the actual operating conditions of the lubricating oil supply system (oil temperature, kinematic viscosity of oil, discharge flow rate of hydraulic pump, etc.). Can be done.

Therefore, in the lubricating oil supply system monitoring device 100 according to the present embodiment, the appropriate hydraulic pressure of the lubricating oil supply system at the current actual oil temperature is acquired, and the actual hydraulic pressure at present is monitored while being compared with the appropriate hydraulic pressure. In addition, the appropriate range of hydraulic pressure (range of set upper limit value to set lower limit value) is set based on the appropriate hydraulic pressure, and the abnormality of the lubricating oil supply system is set based on the range and the actual hydraulic pressure. The presence or absence can be determined (detected), and if it is determined that there is an abnormality, an abnormality display can be displayed to warn or the machine can be stopped.

As described above, according to the present embodiment, the appropriate hydraulic pressure of the lubricating oil supply system is acquired by calculation according to the actual temperature of the lubricating oil, and the monitoring values of the upper and lower limits are finely tuned with respect to this appropriate hydraulic pressure. By monitoring the actual oil pressure and comparing this with the above-mentioned upper and lower limit monitoring values, it is possible to detect abnormalities in the lubricating oil supply system with high sensitivity and accuracy. It is possible to prevent a serious failure of the machine due to an abnormal supply of lubricating oil.

Further, in the lubricating oil supply system monitoring device 100 according to the present embodiment, the maximum specified pressure of the lubricating oil pump used is set in advance as the upper limit value of the hydraulic pressure, and the set hydraulic pressure is compared with the actual hydraulic pressure. By monitoring, if the actual oil pressure exceeds the set oil pressure as the upper limit, it is possible to detect an abnormality in the lubricating oil pressure, and if it is determined that there is an abnormality, an abnormality display is displayed. Damage to the lubricating oil pump can be avoided by controlling the warning and stopping the machine.

When operating the present invention, in order to improve the reliability of the piping resistance coefficient acquired by calculation based on the measured values of each lubricating oil supply system, the oil temperature in the environment where the machine is actually installed It is desirable to calculate using the actual measurement of hydraulic pressure and the actual measurement data at multiple temperatures (conditions with different oil temperature conditions).

As described above, according to the present embodiment, the supply state of the lubricating oil in the lubricating oil supply system using the fixed-capacity pump of the machine is accurately monitored while having a relatively simple and low-cost configuration. It is possible to provide a method and a device for monitoring the lubricating oil supply system of a machine.

By the way, for example, when the flow of FIG. 2 is executed in a predetermined cycle such as every time the machine is restarted and the pipe resistance coefficient C is acquired each time, the acquired value of the pipe resistance coefficient C is used. If there is a change, it is possible that the configuration of the lubricating oil supply system has changed over time. Therefore, observe the change in the value of the drag coefficient C and check for any abnormalities over time in the lubricating oil supply system. It is also possible to diagnose. This makes it possible to diagnose the presence or absence of abnormalities over time in the lubricating oil supply system during operation for diagnosis before the machine is fully operated, and it is possible to prevent major damage to the machine. It can contribute to prevention.

The embodiments described above are merely examples for explaining the present invention, and it goes without saying that various modifications can be made without departing from the gist of the present invention.

3 Oil pump 5 Lubricating oil temperature sensor (temperature sensor)
6 Lubricating oil pressure sensor (pressure sensor)
9 Orifice (for example, refueling destinations 1 to n for bearings, etc.)
10 Lubricating oil passage (piping)
11 Lubricating oil reservoir 20 Control device (lubricating oil supply system monitoring control device)
100 Lubricating oil supply system monitoring device

Claims (12)

A method for monitoring the lubricating oil supply system of a machine that monitors the supply status of the lubricating oil in the lubricating oil supply system that uses a constant-capacity pump to supply lubricating oil to each part of the machine.
A pressure information acquisition unit that acquires pressure-related information related to the pressure of the lubricating oil in the lubricating oil supply system,
A temperature information acquisition unit that acquires temperature-related information related to the temperature of the lubricating oil in the lubricating oil supply system, and
Equipped with
The temperature of the actual lubricating oil is acquired based on the temperature-related information from the temperature information acquisition unit, the appropriate hydraulic pressure to be generated at the temperature of the actual lubricating oil is acquired by calculation, and the pressure information acquisition unit is used. Obtaining the actual lubricating oil pressure based on the pressure-related information from, and monitoring the lubricating oil supply status of the lubricating oil supply system while comparing the actual lubricating oil pressure with the proper hydraulic pressure. A method for monitoring the lubricating oil supply system of the machine as a feature. The proper hydraulic pressure is
When this lubricating oil supply system is a single circular tube, the actual lubricating oil pressure at the temperature of any lubricating oil, the kinematic viscosity of the lubricating oil at the temperature of the arbitrary lubricating oil, and the density of the lubricating oil , The piping resistance coefficient obtained by calculation based on the flow rate of lubricating oil,
The kinematic viscosity of the lubricating oil at the actual temperature of the lubricating oil,
The lubricating oil supply system monitoring method according to claim 1, wherein the oil is obtained based on the above. The pipe resistance coefficient is the actual pressure of the lubricating oil at the temperature of the arbitrary lubricating oil, the kinematic viscosity of the lubricating oil at the temperature of the arbitrary lubricating oil, the density of the lubricating oil, the flow rate of the lubricating oil, and the said. The lubricating oil supply system monitoring method according to claim 2, wherein the head of the lubricating oil supply system is obtained by calculation based on the lift. The comparison between the actual pressure of the lubricating oil and the appropriate hydraulic pressure is characterized by comparing the upper and lower limit monitoring values set based on the appropriate hydraulic pressure with the actual pressure of the lubricating oil. The lubricating oil supply system monitoring method according to any one of claims 1 to 3. The pipe resistance coefficient is
Piping resistance coefficient C = ΔP / (ν × γ × Q)
Q: Lubricating oil flow rate (cm ³ / sec)
ΔP: Actual lubricating oil pressure (pressure loss) (MPa)
ν: Dynamic viscosity of lubricating oil (cm ² / sec: St)
γ: Lubricating oil density (kg / cm ³ )
The lubricating oil supply system monitoring method according to claim 2 or 4, wherein the oil is obtained by the following formula. The pipe resistance coefficient is
Piping resistance coefficient C = (ΔP－h × γ × g × 10 ^-4 ) / (ν × γ × Q)
Q: Lubricating oil flow rate (cm ³ / sec)
h: Lift (cm)
g: Gravity acceleration (g = 980cm / sec ² )
ΔP: Actual lubricating oil pressure (pressure loss) (MPa)
ν: Dynamic viscosity of oil (cm ² / sec: St)
γ: Oil density (kg / cm ³ )
The lubricating oil supply system monitoring method according to claim 3 or 4, wherein the oil is obtained by the following formula. A machine's lubricating oil supply system monitoring device that monitors the lubricating oil supply status of the lubricating oil supply system that uses a constant-capacity pump to supply lubricating oil to each part of the machine.
A pressure information acquisition unit that acquires pressure-related information related to the pressure of the lubricating oil in the lubricating oil supply system,
A temperature information acquisition unit that acquires temperature-related information related to the temperature of the lubricating oil in the lubricating oil supply system, and
With
The actual lubricating oil temperature is acquired based on the temperature-related information from the temperature information acquisition unit, and the appropriate hydraulic pressure to be generated at the actual lubricating oil temperature is acquired by calculation, and the pressure information acquisition unit is used. Lubricating oil that obtains the actual lubricating oil pressure based on the pressure-related information from, and monitors the lubricating oil supply status of the lubricating oil supply system while comparing the actual lubricating oil pressure with the proper hydraulic pressure. Supply system monitoring and control device,
A machine lubricant supply system monitoring device characterized by being configured with. The proper hydraulic pressure is
When this lubricating oil supply system is a single circular tube, the actual lubricating oil pressure at the temperature of any lubricating oil, the kinematic viscosity of the lubricating oil at the temperature of the arbitrary lubricating oil, and the density of the lubricating oil , The piping resistance coefficient obtained by calculation based on the flow rate of lubricating oil,
The kinematic viscosity of the lubricating oil at the actual temperature of the lubricating oil,
The lubricating oil supply system monitoring device for a machine according to claim 7, wherein the device is obtained based on the above. The pipe resistance coefficient is the actual pressure of the lubricating oil at the temperature of the arbitrary lubricating oil, the kinematic viscosity of the lubricating oil at the temperature of the arbitrary lubricating oil, the density of the lubricating oil, the flow rate of the lubricating oil, and the said. The lubricating oil supply system monitoring device for a machine according to claim 8, wherein the lifting of the lubricating oil supply system is obtained by calculation based on the lift. The comparison between the actual lubricating oil pressure and the appropriate hydraulic pressure is performed by comparing the upper and lower limit monitoring values set based on the appropriate hydraulic pressure with the actual lubricating oil pressure. The lubricating oil supply system monitoring device according to any one of claims 7 to 9, which is characterized. The pipe resistance coefficient is
Piping resistance coefficient C = ΔP / (ν × γ × Q)
Q: Lubricating oil flow rate (cm ³ / sec)
ΔP: Actual lubricating oil pressure (pressure loss) (MPa)
ν: Dynamic viscosity of lubricating oil (cm ² / sec: St)
γ: Lubricating oil density (kg / cm ³ )
The lubricating oil supply system monitoring device according to claim 8 or 10, wherein the lubricating oil supply system is obtained by the following formula. The pipe resistance coefficient is
Piping resistance coefficient C = (ΔP－h × γ × g × 10 ^-4 ) / (ν × γ × Q)
Q: Lubricating oil flow rate (cm ³ / sec)
h: Lift (cm)
g: Gravity acceleration (g = 980cm / sec ² )
ΔP: Actual lubricating oil pressure (pressure loss) (MPa)
ν: Dynamic viscosity of lubricating oil (cm ² / sec: St)
γ: Lubricating oil density (kg / cm ³ )
The lubricating oil supply system monitoring device according to claim 9 or 10, wherein the lubricating oil supply system is obtained by the following formula.

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