1、英文原文wear 181-183 (1995) 868-875Case StudyTheoretical and practical aspects of the wear of vane pumpsPart B. Analysis of wear behaviour in the Vickers vane pump testA. Kunz a, R. Gellrich b, G. Beckmann c, E. Broszeit a a Institute of Material Science, Technical University Darmstadt, P.O. Box 11 1452
2、 64229 Darmstadt,Gcmb University for Technol08y, Economy and Social Science Zittau/Goditz, Facuky of Maihematics, P.O. Box 264, 02763 Zutau cPetersiliensrr. 2d, 03044 Cottbus, Received 16 August 1994; accepted l November 1994Abstract The wear behaviour of the vane pump used in the standard method f
3、or indicating the wear characteristics of hydraulicfluids (ASTM D 2882/DIN 51 389) has been examined by comparison of the calculated wear and experimental data using alubricant without any additives. In addition to the test series according to DIN 51 389, temperature profiles from the pump have been
4、 analysed using the bulk temperatures of the contacting components and the temperature in the lubrication gap as input data for the wear calculation. Cartridges used in tests according to the Gennan standard have been examined extensively before and after each run to obtain input data for the mathem
5、atical model and to Jocate wear. An analysis of the :tluid properties and an investigation of the innuence of wear particles in the hydraulic circuit were performed. The experimental results were compared with the wear prediction, which was verified by the agreement in terms of load, temporal wear p
6、rogress and local wear. Conclusions have been drawn with regard to the validity of the load assumptions and wear calculation, as well as to the limits of applicability of this method in the presence of additives.Keywords: Vane pumps; Hydraulic fluids; Wear prediction; Vickers vane pump test1. Introd
7、uction Efforts to develop a mathematical tool for wearprediction will not be successful without considering wear and its phenomena. The task of Part B of this study is to describe the analysis of the wear behaviour in the tribo system investigated and how the knowledge achieved influences the calcul
8、ations. Input data are derived from the measurement of mechanical and geometrical quantities, such as the hardness, stylus profilometry, fluid properties and contact radii. Thermal quantities are also essential for the modelling of lubrication. The calculations must be verified with wear data. Becau
9、se the tribo system to be analysed is the vane pump employed in the Vickers vane pump test,which has been in use for about 40 years, several wear data can be used for comparison between calculated and measured wear results. These are the wear masses0043-1648/95/$09.50 1995 Elsevier Science S.A. All
10、rights reserved SSDI 0043-1648(94)07087-3 after each tcst run, the progrcssion of wear over time and the local wear on the inner ring surface; in combination, these enable a comprehensive statement to be made on the validity of the mathematical model described in Part A.2. Experiments AlI Vickers va
11、ne pump tests described were run with the same fiuid. It is a reference oil of the German Rcscarch Association for Transmission Technique (FVA), and is a mineral oil without any additives (FVA3). Thus the disturbing influences of additives can be excluded.2./.Input data for calculation Fig. 1 lists
12、the input and output quantities of the calculations. Most of the input parameters were derived surface profiles contact force and contact velocity dynamic viscosity contact radiihardness values Youngs moduli, Poisson numbersand lubrication gapspecific shear energy densities* pressure exponentc,f vis
13、cosity; tlubrication gap temperatureRough surfuce shaar energy hypot elasto liubictionWm=f（t）Wf =f（）Fig. 1. Input parameters and output quantities of the mathematicalmodel of Part A.Fig. 2. Cartridge V 104 C: bushing, rotor, ring, bushing (abcwe),single vane, pin (below).experimentally from all the
14、components involved beforeand after use in the vane pump tests. The mechanical components, which must be renewed for each test run,are shown in Fig. 2. Such a cartridge kit consists of a rotor, ring, 12 vanes, bushings and pin.Stylus profilometry was performed on the inner surface of the ring and on
15、 the tips of two vanes of the cartridge before and after each test run. Earlier investigations have shown that ten parallel sections in the sliding direction on each body are sufficient to describe the surface topography in a statistically satisfactory manner as a two-dimensionalisotropic gaussianfi
16、eld according to Ref. 1. Only the high pass filtered components of the profile (sampling length, 1.5 mm; cut o五 0.25 mm) were used to determine the spectral moments mo, m2, m4 and the parameter of roughness a. According to the partition of the contact force into different loading zones, the topograp
17、hic data of the new surfaces were used for zone IV (low level load, see Part A). For the other zones with higher contact forces, the profiles of the surfaces in the final condition were used, which corresponds to the appearance of the inner ring surface after the test runs. The contact force and con
18、tact velocity were calculated with different fluid pressures and dynamic forces acting on the vanes, revolution number and ring radu, whereas the change in contact radius was documented with a profile projector. Because the ring radii are much larger thar) the radii of the vanes in the contact zone,
19、 the vanes can be assumed to be hertzian cylinders slidingalong a plane surface and the contact radii are simply the radii of the vane tips. Each vane tip was twice drawn up at magnifications of 100 : 1 and the contact radii and contact locations were measured with a stenciLMean values of the contac
20、t radii were transferred to the calculation, which is based (similar to the surfaceprofiles) on vanes in both conditions. The Vickers hardness HVlO was measured on thering and three vanes of each cartridge. This hardnessleads to a better reproducibility than microhardness values, but due to the larg
21、e indenter load, it couldonly be taken after the test runs. Therefore changes in hardness values could not be registered. The Youngs moduli, Poisson numbers and densities of the ring (AISI 52100) and vane materials (M2 reg C) are the first input parameters in the shear energy hypothesis and were obt
22、ained from the literature. The specific shear energy densities (see Part A) are materialspecific constants 2l. The fluid properties (Fig. 1) were measured, derived from the literature or calculated. To obtain the dynamicviscosity, the densities and kinematic viscosities at 20,40 and 80 0C were measu
23、red. Because the fluid is a reference oil of FVA, the pressure exponent of the viscosity is given 3. The temperature in the lubrication gap between the ring and vanes was approx:imated by measurements and calculations described below.2.2. Temperature profiles Temperature measurement was performed to
24、 obtain information on how a heatable tribometer must be controlled to simulate the wear behaviour of the vane pump. Therefore shortened test runs were carried out until temperatures were stabilized. These 10 h vane pump tests delivered the input data for the approximation of the lubrication gap tem
25、perature in the ring-vane contact, as well as additional wear masses to be compared with the calculated progressiort of wear in time. The sampling principles for acquiring the temperature profiles of the vane pump are illustrated in Fig. 3. The temperature of the lubricant in the gap between the rin
26、g and vanes was estimated to be equal to or greater than the bulk temperature on the inner ring surface. Following the first main statement of thermodynamics, the heat flux Q mp into the components of the pump can be derived from with the fluid as the medium for energy transport.Qa,mp can only be tr
27、ansferred to the components shownin Fig. 2. For the same temperature differences and materials, this heat nUX can be divided into single component fluxes ac cording to the relation of masses. The derived flux Qring is the heat which flows in a certain time period in a radial direction through the ri
28、ng. With the known temperatures on the outer ring surface, the bulk temperatures on the inner ring surfacecan be calculated and transferred to the model of elastohydrodynamic lubrication. All test runs with the Vickers vane pump V 104 C were performed on a test rig according to ASTM D2882/DIN 51 389
29、 which is shown schematically in Fig.4. These standards describe the procedure for testingthe anti-wear properties of hydraulic fiuids. To start the Vickers vane pump test according to the German standard, the system pressure must be raised in steps of 2 MPa every 10 min, beginning at 2 MPa, until
30、a final pressure of 14 MPa is reached. At this stage, the fluid temperature measurcd bcfore the pump (see Fig.4) must be controlled to guarantee a kinematic viscosity of 13 mm2 S-i at the inlet for every :tluid tested. These conditions must be maintained until the test is aborted normally after 250
31、h by opening the bypass of the pressure control valve before the motor is stopped. By a comparison of the wear achieved on the ring and vanes with the upper wear limits, the anti-wear properties of the fluid tested can be derived. For performing the tests safely with the fluid FVA3, it was preheated
32、 t0 40 0C and circulated in a pressurefree way. The damage which may occur during the critical first hour of the runs can be avoided using TiNcoated bushings 4. For comparison with the results derived from computation, the wear produced in these runs must be documented as amounts, both locally and t
33、emporally. The wear masses were derived from the weight differences of the ring and vanes before and after each run. They were obtained from a sequence of four 250 h test runs and tw0 10 h runs for temperature measurement. The local linear amount of wear was documented by the differences in the inne
34、r ring radii perdegree of revolution, which were measured by surface digitization along the inner ring surface at three different positions of the ring width before and after the tesi runs. In earlier investigations 5, the wear progression over time of the vanes was measured under identical testing
35、conditions, except for a lower fluid temperature. For this experiment, the radiotracer technique was used. Two vane tips in the set of 12 vanes of each cartridge were radiologically activated by bombardment with protons. A detector close to the pump body allowed thedecrease in radiological activity
36、to be monitored continuously, which was found to be reciprocally proportional to the linear amount of vane wear as a function of time 5l. Due to the good tempering properties of the vane material (M2 reg C), with a specific secondary hardness maximum between 450 and 550 0C, the infiuence of the acti
37、vation process at 220 0C on the wearbehaviour of the activated zone of the vane tips could be excluded.Phyd+Pfric-Qcomp-Qfluid=0 (1) Qfluid=mcfluidTfluid (2) Fig. 4. Hydraulic circuit of the test rig.3 resultlines the statistical reliability of surface modelling as a two-dimensional isotropic gaussi
38、an field. Although only the filtered profiles scanned in the sliding direction are shown, a distinct change in surface roughness is obvious. A good representation of the wear phenomena (see Part A) by the input data for the wear calculation derived from these profiles can be assumed. The change in t
39、he vane tip shape over the testing period is documented in Part A. The hardness values for the rings and vanes varied from 743 t0 769 HVlO (rings) and from 778 t0 816 HVlO (vanes). In all cases, the vanes of one cartridge had higher hardness values than the ring, but these differences varied and had
40、 a large influence on the wear calculation (see Part A).The measurement of the fiuid properties led, in combination with the kinematic viscosity prescribed by the German standard, to a fluid temperature of 84-86oC at the pump inlet. Together with the other temperature measurements acquired in the 10
41、 h runs, these temperature profiles are illustrated in Fig. 6. Test Number t was found that, in about l h, all temperatures were stabilized. It should be noted that all temperatures in or on the pump components are higher than the fluid temperature measured behind the pump. The highest temperatures
42、were found on the outer ring surface,with significant differences depending on the location of the thermocouples. The calculation of the bulk temperatures on the inner ring surface via the heat flux balance eliminated the infiuence of the different ring thicknesses at the scan locations. Depending o
43、n tbese different distances for heat conduction, between 4 and 7 0C must be added to the mean values of the component temperatures to obtain the surface temperatures. These values are 20c70 higher than the fluid temperature measured behind the pump, which was used as input data for the wearcalculati
44、on. During the l h starting phase of the test runs, the stepwise increase in system pressure leads to an immediate effect on the component temperatures, whereas the fluid temperature increases with a more or less constant gradient, which demonstrates the association of load and frictional heat. The
45、four 250 h test runs caused a mixture of adhesive and abrasive wear at a high level (see Part A). The wear results achieved are shown in Fig. 7. Ring wear increased from test I to test 3. Therefore the 12 pm filter normally used was replaced after the third test by a 3 pm filter, and a pressure-free
46、 run with an additional cartridge was started as a cleaning procedure. Due to the filter change, the reservoir needed to be refilled by about lOv-/o of its content with fresh fluid before control test 4, again with a 12 ym filter, was started. In addition to these efforts to minimize possible wear p
47、article influence, a comparison of the viscosity and neutralization number with those of fresh fluid showed only an insignificant rise in viscosity and a low neutralization number after 750 h of testing. In test 4, the highest value for ring and vane wear at a constant level was achieved. For all te
48、sts, the linear amount of wear on the ring surface showed a strong dependenceon the measurement location with strictly limited areas of high and low wear. The results of continuous vane wear monitoring are shown in Fig. 8 in addition to the principle of measurement. Degressive wear laps were found, where the stationary level was reached after 100 h.4. Discussion Before the wear calculations can be verified by wear data, it must
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