Method for determining the life state of a vibration damper or shock absorber and device for carrying out the method

Abstract

According to the invention, a method for determining the service life condition of a vibration damper (1), in particular a torsional vibration damper or shock absorber, comprises a main mass and a secondary mass, and a working chamber arranged between the main mass and the secondary mass, the working chamber being filled with a viscous damping medium, wherein the vibration damper (1) is arranged on a crankshaft (7) of an engine (8), in particular an internal combustion engine, and in order to suppress or eliminate torsional vibrations of the crankshaft (7), the crankshaft (7) constituting a part of the engine (8) is designed to have the following steps when operating the engine (8): S1) operating the engine (8); S2) determining at least one operating parameter of the engine (8); S3) simulating the temperature distribution of the viscous damping medium in the working chamber; and S4) determining the service life condition of the vibration damper (1) based on the operating parameter of the engine (8) and the result of simulating the temperature distribution of the viscous damping medium. Components for carrying out the method are also provided.

Description

Technical Field

[0001] The invention relates to a method for determining the service life condition of a vibration damper, in particular a torsional vibration damper or a vibration absorber, according to the preamble of claim 1. The invention also relates to a device for carrying out such a method. Background Art

[0002] Vibration dampers can be used to damp mechanical vibrations of vibrating devices in various ways. For example, to damp torsional vibrations, they are used in conjunction with a damping device arranged between the crankshaft and the drive train of an internal combustion engine, such as a piston engine. Torsional vibration dampers can also be mounted on the free end of the crankshaft.

[0003] The torsional vibration damper can be designed as a so-called viscous damper (visco-damper), which, for example, has a housing as the primary mass, an annular working chamber, and a flywheel ring as the secondary mass. The flywheel ring is arranged in the annular working chamber so that it can rotate relative to the housing and is surrounded by a viscous damping medium.

[0004] Viscous damping media are, for example, silicone oils. Damping media age over time. Significant aging factors are stresses caused by high temperatures, air intake, catalytic processes, and the type and amount of any impurities. The service life of viscous damping media is crucially dependent on the temperature of the medium.

[0005] Document EP 3 242 055 B1 describes a wear indicator for a vibration damper. The temperature of the vibration damper is measured. The temperature of the damping medium is a key factor.

[0006] However, it is considered disadvantageous that the temperature of the damping medium cannot be measured directly from the outside. This is because the temperature of the damping medium is strongly dependent on the radius and also has a very steep gradient across the damping gap in which the damping medium is arranged (e.g., 35°C within 0.6 mm). Attempts to determine the temperature of the damping medium very precisely by measurement are extremely difficult, since measurements must be taken at various points in the damping medium. Summary of the Invention

[0007] It is therefore an object of the present invention to provide an improved method for determining the service life condition of a vibration damper, in particular a torsional vibration damper or vibration absorber.

[0008] This object is achieved by a method according to claim 1 .

[0009] The object is also achieved by an assembly according to claim 14 .

[0010] The concept of the invention is based on the fact that the temperature distribution of the damping medium is simulated. This simulation is performed as a function of the operating state of the machine.

[0011] According to the method of the present invention for determining the service life condition of a vibration damper, in particular a torsional vibration damper or vibration absorber, the vibration damper having a main mass and a secondary mass, and having a working chamber arranged between the main mass and the secondary mass, the working chamber being filled with a viscous damping medium, wherein the vibration damper is arranged on a crankshaft of an engine, in particular an internal combustion engine, in order to damp or eliminate torsional vibrations of the crankshaft, the crankshaft forming part of the engine, and the method is designed to have the following steps when the engine is operated: S1) operating the engine; S2) determining at least one operating parameter of the engine; S3) simulating the temperature distribution of the viscous damping medium in the working chamber; and S4) determining the service life condition of the vibration damper based on the operating parameter of the engine and the result of simulating the temperature distribution of the viscous damping medium.

[0012] A particular advantage is that the process can be performed without measuring the temperature of the damping medium.

[0013] The assembly according to the invention for determining the service life condition of a vibration damper, in particular a torsional vibration damper or shock absorber, comprises a vibration damper and a machine having a machine controller. The assembly also comprises an evaluation device having a computer unit and at least one memory device for storing data, the computer unit having at least one simulation program for temperature distribution.

[0014] Particularly advantageously, no complex measurement technology with associated installation is required. The assembly is designed to carry out the method of the present invention described above. Only variables that are already known in some way, such as machine operating data, are evaluated. These known variables can be easily obtained from the machine control system.

[0015] Advantageous further aspects of the invention are the subject matter of the dependent claims.

[0016] In one aspect of the method, steps S1) and S2) are repeated at predetermined intervals during operation of the machine and fatigue life conditions of the vibration damper are determined based on a plurality or all of the operating parameter determinations and temperature distribution simulations performed.

[0017] It is advantageous here if the operating parameters are the operating times of the machine, since these values ​​are available and can be obtained in a simple manner from the machine control system, for example as electrical data values.

[0018] Another aspect of the invention provides that when simulating the temperature distribution of the viscous damping medium, a three-dimensional temperature distribution is determined as the temperature field of the viscous damping medium in the working chamber. The precise simulation of the three-dimensional temperature field of the damping medium makes it possible to obtain significantly more precise information about the temperature distribution in the vibration damper, depending on the operating state of the machine and thus also advantageously over the service life of the vibration damper.

[0019] It is further provided that the primary mass comprises an annular housing with an annular working chamber, and the secondary mass is a flywheel ring disposed within the annular housing. A gap filled with a viscous damping medium (particularly silicone oil) is formed between the flywheel ring and the housing in the working chamber. During the simulation of the temperature distribution of the viscous damping medium, a three-dimensional temperature distribution of the viscous damping medium within the gap in the working chamber is determined. Advantageously, no sensor is required for this purpose.

[0020] It is also advantageous if the temperature distribution can be simulated as a temperature field of the viscous damping medium for different operating states of the machine, since this allows a more precise statement of the service life of the vibration damper.

[0021] Alternatively, the simulated values ​​of the temperature field of the viscous damping medium can be used to determine the associated degradation rate of the damping medium and compared with previously stored values ​​of the degradation rate of the damping medium as a reference value. In this way, the lifespan can be determined quickly and accurately.

[0022] Previously stored values ​​of the degradation rate of the damping medium can be stored as reference values ​​for all operating conditions, preferably in a file designed as a "lookup table". This provides fast access to the reference value, which can of course be specified more precisely at specific intervals by subsequent addition.

[0023] It is therefore advantageous to determine the instantaneous degradation rate of the damping medium by comparing it with a previously stored reference value. This allows an up-to-date statement about the state of the vibration damper.

[0024] Advantageously, by integrating the determined degradation rate of the damping medium over time, damage to the vibration damper can be determined and thus the service life can be predicted.

[0025] In this way, an output, an alarm, a warning or the like can advantageously be issued when a previously defined limit value is exceeded.

[0026] In another form, at least one calibration using measurements of another parameter, such as the external temperature of the vibration damper at a previously defined point, may be used for additional calibration of the simulation.

[0027] The ambient temperature may also be used optionally or during operation of the machine and the vibration damper in order to be able to state the service life of the vibration damper more precisely.

[0028] In addition, the following advantages are obtained compared with the prior art.

[0029] - No complex measurement technology is required; instead, only variables that are known in each case are evaluated. This allows for a more precise prediction of the three-dimensional temperature field and thus of the service life of the vibration damper.

[0030] ——The three-dimensional temperature field and therefore the life span can be predicted more accurately.

[0031] - Short-term temperature changes in the damping medium can be taken into account, which, for example, would not be noticed at all if only the temperature outside the damper was measured. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Examples of various aspects of the present invention are described below using the accompanying drawings.

[0033] In the accompanying drawings

[0034] Figure 1 A schematic block diagram showing components according to the present invention;

[0035] Figure 2 shows a schematic partial cross-sectional view of a vibration damper;

[0036] Figure 3 Show the basis Figure 2 A schematic cross-sectional view of a gap of a vibration damper;

[0037] Figure 4 a schematic cross-sectional view showing an internal vibration damper; and

[0038] Figure 5 is a schematic flow chart of the method according to the present invention. DETAILED DESCRIPTION

[0039] Figure 1 A schematic block diagram shows an arrangement according to the invention for determining the service life condition of a vibration damper 1 , in particular a torsional vibration damper or a vibration absorber.

[0040] The assembly comprises a vibration damper 1 , a machine 8 with a machine controller 9 and an evaluation device 10 .

[0041] Here, the vibration damper 1 is designed as a torsional vibration damper and is mounted on a crankshaft 7 of a machine 8 in order to damp or eliminate torsional vibrations of the crankshaft 7. The crankshaft has a crankshaft axis 7a.

[0042] The machine 8 is, for example, a piston engine. The machine controller 9 is connected to an evaluation unit 10 via one or more transmission lines.

[0043] The evaluation device 10 comprises a computer unit 11 having at least one simulation program for temperature distribution and at least one memory device 12 for storing data.

[0044] Furthermore, the evaluation device 10 determines the current and remaining service life of the vibration damper 1 and outputs information and alarms via the output 13. For example, if a limit value for damage or end of service life of the vibration damper 1 is determined, an alarm is triggered.

[0045] The output 13 is connected to the evaluation unit 10 or is integrated in the evaluation unit 10. The output 13 can be a screen, a printer, an interface, an optical output, an acoustic output and / or a tactile output.

[0046] Furthermore, the arrangement comprises at least one sensor 14 , with which the ambient temperature of the vibration damper 1 can be recorded.

[0047] The arrangement is designed to carry out the method described in detail below for determining the service life condition of a vibration damper or vibration absorber, ie, the vibration damper 1 .

[0048] This method can be used to determine the service life of a viscous damper, for example, a vibration damper 1. For this purpose, the temperature distribution of the damping medium of the vibration damper 1 is accurately simulated by the computer unit 11 of the evaluation unit 10. This simulation is performed based on the operating state of the machine 8, which is transmitted to the evaluation unit 10, for example, in the form of data values ​​from the machine controller 9.

[0049] Figure 2 A schematic partial sectional view of a vibration damper 1 is shown, which is designed as a torsional vibration damper having an axis of rotation 1 a .

[0050] The coordinates x, y, and z are used for orientation. The x coordinate extends in the direction of the rotation axis 1a, the y coordinate is at right angles to the rotation axis, and the z coordinate is at right angles to the rotation axis. Figure 2 In the radial direction.

[0051] The design and function of the torsional vibration damper are assumed to be known and will not be described in detail here. In this respect, reference is made, for example, to document EP 3 242 055 B1.

[0052] The vibration damper 1 has an annular housing 2 as a primary mass and a flywheel ring 3 as a secondary mass arranged in a working chamber 2a of the housing 2. The working chamber 2a is designed as an annular chamber.

[0053] The housing 2 and the flywheel ring 3 are arranged coaxially with the rotation axis 1a and are rotatable about the rotation axis. The flywheel ring 3 is mounted in the housing 2 so as to be rotatable relative to the housing 2. The bearings are not shown.

[0054] A gap 4 is formed between the flywheel 3 and the housing 2. The gap 4 is filled with a damping medium, such as silicone oil. The damping depends on the viscosity of the damping medium.

[0055] The vibration damper 1 is installed as a torsional vibration damper, for example, in an internal combustion engine, for example a piston engine (see Figure 4 ) on the crankshaft 7. When the vibration damper 1 is in operation, the damping medium in the gap 4 heats up and the generated heat is distributed to the housing 2 and the flywheel ring 3.

[0056] exist Figure 2 In FIG, such a temperature distribution is shown as an example for a temperature field 5 of a flywheel 3. For this purpose, the cross section of the flywheel 3 is divided into different temperature ranges 5-1 to 5-9 extending from a radially outer region of the flywheel 3 in the direction of the rotation axis 1a.

[0057] For this example, a temperature field 5 having a temperature range 5-1 to 5-9 has been simulated using an appropriate computer program. The temperatures in the table below have been calculated and assigned to Figure 2 The temperature range shown is 5-1 to 5-9.

[0058] Table 1: Temperature field 5

[0059] Temperature range Temperature [°K] 5-1 402 5-2 400 5-3 397 5-4 395 5-5 393 5-6 392 5-7 390 5-8 390 5-9 389

[0060] It can be seen that the majority of the outer radial cross section of the flywheel 3 having the temperature range 5-1 has the highest temperature.

[0061] Figure 3 Shown along the basis Figure 2 Schematic cross-sectional view of the gap 4 of the vibration damper 1 taken along line II-II.

[0062] The gap 4 is shown as a rectangle having a radial extent 4a in the z-direction and a transverse extent in the y-direction. Furthermore, the gap 4 is shown with a grid representing a simulated temperature field 6 .

[0063] In the simulation program, the temperature field 6 is divided into finite elements 6a. This is shown here only two-dimensionally in the yz plane. The finite elements 6a can also be three-dimensional finite volume elements.

[0064] Finite elements 6 a of the temperature field 6 are arranged in the radial z direction starting from the outer radius of the gap 4 toward the axis of rotation 1 a in layered temperature ranges 6 - 1 to 6 - 7 .

[0065] The division of the gap 4 into a certain number of layered temperature ranges 6-1 to 6-7 and into a certain number of finite elements 6a can be adapted to different boundary conditions. The numbers shown here are merely exemplary.

[0066] The following table shows Figure 2 The temperature ranges 6-1 to 6-7 shown in FIG. 6 are assigned simulation calculation temperatures in this example.

[0067] Table 2: Temperature field 6

[0068] Temperature range Temperature [°K] 6-1 390...392 6-2 392 6-3 394...396 6-4 396 6-5 398 6-6 400 6-7 402

[0069] The calculation and analysis of the finite element 6 a can be performed on the radial length 4 a , the transverse length 4 b and the circumferential length of the gap 4 .

[0070] The temperature field 6 has the highest temperatures in the layers directly in contact with the outer radius of the flywheel 3, starting from the boundary layer in the temperature range 6-7 and above, for example, up to the temperature range 6-4. These damping medium layers are exposed to high shear forces and therefore high internal friction.

[0071] The temperature of the damping medium depends strongly on the radius of the gap 4 and has a very steep gradient across the gap, for example 35° C. over a distance of 0.6 mm.

[0072] An accurate simulation of the three-dimensional damping medium temperature field 6 provides more accurate information about the temperature distribution in the vibration damper 1 as a function of the operating state of the machine and thus also about the service life of the vibration damper 1 .

[0073] Figure 4 A schematic cross-sectional view of an internal vibration damper 1 ′ with temperature simulation is shown.

[0074] Here, only the three temperature ranges 5'-1 to 5'-3 of the corresponding temperature field 5' are input. The temperatures of the corresponding relevant temperature ranges 5'-1 to 5'-3 are given in the table below.

[0075] Table 3: Temperature field 5'.

[0076] Temperature range Temperature [℃] 5’-1 144 5’-2 139 5’-3 133

[0077] Figure 5 A schematic flow chart of a method according to the invention for determining the service life condition of a vibration damper or vibration absorber, for example the vibration damper 1 , is shown.

[0078] In a first process step S1 , a machine 8 , such as a piston engine, an internal combustion engine or the like, is operated.

[0079] In a second process step S2, at least one operating parameter of the machine 8 is determined. This is achieved by sending specific data values ​​of the machine controller 9 to the evaluation device 10.

[0080] For example, such an operating parameter of the machine 8 may be the operating time of the machine 8 .

[0081] In a third process step S3 , the temperature distribution of the viscous damping medium, ie the temperature field 6 , in the working chamber 2 a , 2 ′ a of the vibration damper 1 is simulated. This simulation is performed by means of one or more simulation programs in the computer unit 11 of the evaluation unit 10 .

[0082] The simulation preferably determines the three-dimensional temperature distribution of the viscous damping medium in the working spaces 2 a , 2 ′ a and in the intermediate space 4 of the working spaces.

[0083] Finally, in a fourth process step S4 , the life condition of the vibration damper 1 is determined based on the operating parameters of the machine 8 and the results of the simulation.

[0084] Process steps S1 and S2 are repeated at predetermined intervals during operation.The service life condition is determined based on most or all of the operating parameter determinations and temperature distribution simulations performed.

[0085] Furthermore, a calibration using, for example, a measurement of the external temperature at a point of the vibration damper by sensor 14 can be used for additional calibration of the simulation model. The ambient temperature can also be used on a time basis or also during operation of the machine 8 and the vibration damper 1.

[0086] The three-dimensional temperature field 6 of the damping medium can also be determined for different operating conditions.

[0087] Using the analog value, the relevant degradation rate of the damping medium is determined and compared with a previously stored reference value. If the limit value is exceeded, an output, alarm, warning, etc. can be issued.

[0088] The previously stored reference values ​​may be stored in a table form in a file ("lookup table") in the memory 12 of the evaluation unit 10 as a list of degradation rates for all operating conditions.

[0089] In this way, the instantaneous degradation rate may be determined and / or displayed.

[0090] The damage of the vibration damper 1 can be determined by integrating the degradation rate over time and can also be stored, for example, for inspection purposes.

[0091] The present invention is not limited to the above-described design examples, but can be modified within the scope of the claims.

[0092] It is conceivable that the evaluation device 10 can be fully or partially integrated into the machine controller 9 .

[0093] Reference Signs List

[0094] 1 Vibration damper

[0095] 2. 2' shell

[0096] 2a, 2'a working chamber

[0097] 3. 3' flywheel

[0098] 4, 4' gap

[0099] 4a Radial length

[0100] 4b Horizontal length

[0101] 5 Temperature field

[0102] 5-1...5-9 Temperature range

[0103] 6 Temperature field

[0104] 6a Finite Element

[0105] 6-1...6-7 Temperature range

[0106] 7 Crankshaft

[0107] 7a Crankshaft axis

[0108] 8 Machine

[0109] 9 Machine Controller

[0110] 10 Evaluation Device

[0111] 11 Computer Unit

[0112] 12 Storage Devices

[0113] 13 Output

[0114] 14 Sensors

[0115] Steps S1, S2, S3, and S4

[0116] x, y, z coordinates

Claims

1. A method for determining the service life condition of a vibration damper (1), said vibration damper having a primary mass and a secondary mass and having a working chamber (2a, 2'a) arranged between said primary mass and said secondary mass and filled with a viscous damping medium, wherein: The vibration damper (1) is arranged on a crankshaft (7) of an engine in order to suppress or eliminate torsional vibrations of the crankshaft (7), the crankshaft (7) constituting a part of the engine, and the method is designed to have the following steps when operating the engine: S1) operating the engine; S2) determining at least one operating parameter of the engine; S3) simulating the temperature distribution of the viscous damping medium in the working chamber (2a, 2'a); and S4) determining a life condition of the vibration damper (1) based on the operating parameters of the engine and a result of simulating the temperature distribution of the viscous damping medium, wherein the simulation of the temperature distribution as the temperature field (6) of the viscous damping medium is performed for different operating states of the engine, wherein, with the aid of the simulated value of the temperature field (6) of the viscous damping medium, a relevant degradation rate of the viscous damping medium is determined and the relevant degradation rate is compared with a previously stored degradation rate value of the viscous damping medium as a reference value, It is characterized in that an output, an alarm or a warning is output during the comparison when a previously definable limit value is exceeded.

2. The method according to claim 1, characterized in that Steps S1) and S2) are repeated at predetermined intervals during operation of the engine, and a service life condition of the vibration damper (1) is determined based on a plurality or all of the performed operating parameter determinations and temperature distribution simulations.

3. The method according to claim 1 or 2, characterized in that The operating parameter is the operating time of the engine.

4. The method according to claim 1 or 2, characterized in that When simulating the temperature distribution of the viscous damping medium, a three-dimensional temperature distribution is determined as a temperature field (6) of the viscous damping medium in the working chamber (2a, 2'a).

5. The method according to claim 1 or 2, characterized in that The primary mass comprises an annular housing (2, 2') having an annular working chamber (2a, 2'a), and the secondary mass is a flywheel ring (3, 3') arranged in the annular housing (2, 2'), whereby a gap (4) filled with the viscous damping medium is formed between the flywheel ring (3, 3') and the annular housing (2, 2') in the working chamber (2a, 2'a), and a three-dimensional temperature distribution of the viscous damping medium within the gap (4) in the working chamber (2a, 2'a) is determined during simulation of the temperature distribution of the viscous damping medium.

6. The method according to claim 1 or 2, characterized in that The previously stored degradation rate value of the viscous damping medium is stored as a reference value for all operating conditions.

7. The method according to claim 1 or 2, characterized in that The instantaneous degradation rate of the viscous damping medium is determined by comparison with a previously stored reference value.

8. The method according to claim 1 or 2, characterized in that The damage of the vibration damper (1) is determined by integrating the determined degradation rate of the viscous damping medium over time.

9. The method according to claim 1 or 2, characterized in that At least one calibration using measurements of another parameter is used for additional calibration of the simulation.

10. The method according to claim 9, characterized in that The ambient temperature is used at a point in time or during operation of the engine and the vibration damper (1).

11. The method according to claim 1, wherein The vibration damper (1) is a torsional vibration damper or a vibration absorber.

12. The method according to claim 1, characterized in that The engine is an internal combustion engine.

13. The method according to claim 5, characterized in that The viscous damping medium is silicone oil.

14. The method according to claim 9, characterized in that The further parameter is the external temperature of the vibration damper (1) at a previously determinable point.

15. The method according to claim 6, characterized in that The previously stored degradation rate values ​​of the viscous damping medium are stored in a file formed as a lookup table.

16. An arrangement for determining the service life condition of a vibration damper (1), comprising a vibration damper (1) and a machine (8) having a machine controller (9), characterized in that The assembly further comprises an evaluation device (10) having a computer unit (11) and at least one memory device (12) for storing data, the computer unit having at least one simulation program for temperature distribution, wherein the evaluation device (10) determines the current and remaining service life of the vibration damper (1) and outputs information and warnings via an output (13), It is characterized in that the assembly is designed to carry out the method for determining the service life condition of a vibration damper (1) according to any one of claims 1 to 15.

17. The assembly according to claim 16, characterized in that If a limit value is determined with respect to damage or end of life of the vibration damper (1), an alarm is triggered.

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