Measuring and testing – Frictional resistance – coefficient or characteristics – Lubricant testing
Patent
1999-04-12
2000-09-05
Raevis, Robert
Measuring and testing
Frictional resistance, coefficient or characteristics
Lubricant testing
G01N 1902
Patent
active
061125733
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention concerns a process for determining the lubricant power of lubricant oils.
The use of lubricant oils, especially lubricant oils called "automatic transmission fluids" (ATF), in a slip-controlled clutch presupposes accurate knowledge of the friction value curve as a function of the sliding speed. If, in the operating range the curve of the friction value, dependent on the sliding speed, does not correspond to a progressive curve, it is thus expected that self-exciting friction oscillations will occur in the vehicle. Thus, there is no longer an orderly working of slip-controlled clutches, for example, in regulated converter lock-up clutches.
As a rule, lubricant oils are evaluated, with regard to their fitness for use in slip-controlled clutches, by costly test bench superstructures with original installation parts. The values obtained, of course, should not be assigned at once to the lubricant power, rather, but not until after a certain service life of the lubricant oils. Further tests at regular intervals are needed, but not reasonably possible in cost and time spent. For the same reasons, a widespread analysis in vehicle and/or components tests is mostly eliminated. But the knowledge of these values is indispensable when a long-term fitness for lubricant oils must be guaranteed.
The invention is based on the problem of providing a process and a device with which the lubricant power of lubricant oils for slip-controlled clutches can be determined at a low cost so that decisive statements about a long-term fitness are possible.
SUMMARY OF THE INVENTION
No original installation parts are needed for the process and device according to the invention. Besides, only small quantities of oil, about 100 ml, are required. Thereby, resulting in savings of cost and time in relation to both the test bench structure and the performance of the test. Thus, the lubricant power can now be detected together with vehicle or test bench tests, since only a small fragment of the lubricant oil is removed from the lubricant oil circuit for testing purposes and the residual lubricant oil remains in the long-term test.
The amount of test oil is conveniently limited to less than 200 ml. In addition, the test container and the parts contained therein, such as the specimen holder, etc., can be dimensioned accordingly so that even with small amounts of test oil the contact surfaces are always sufficiently supplied with test oil during the test. It is also possible to situate additional displacement bodies in the test container in order to obtain the desired amount of test oil. For the development of adequate lubricant oils, it is of decisive importance to know the change of the friction value characteristic as a function of the service life. With the process and corresponding device, according to the invention, it is possible to describe friction systems, such as existing in slip-controlled clutches, in relation to their coefficient of friction characteristic curve in different states of processing and utilization. The process and device thus can be used in lubricants for control of production charges in lubricant oil development during test bench or field tests, to test aging processes in a laboratory and for evaluating new friction surfaces.
In the specification and in the claims, numerous features are shown and described in combination. The expert will conveniently consider the combined features also individually, depending on the problems to be solved, and form convenient added combinations.
BRIEF DESCRIPTION OF THE DRAWING(S)
An embodiment of the invention is shown in the drawing in which:
FIG. 1 diagrammatically shows a structure of a device according to the invention;
FIG. 2 shows in enlarged view a range II in FIG. 1; and
FIG. 3 shows the coefficient of friction characteristic curves.
DESCRIPTION OF THE PREFERRED EMBODIMENT(S)
A motor 1 drives, via a torque indicator 2, an input shaft 4, an equalizer connection 3, and a thrust washer 5 on which a ring disc 6 is fastened with a
REFERENCES:
patent: 2909056 (1959-10-01), Neely
patent: 3045471 (1962-07-01), Chapman et al.
patent: 3913377 (1975-10-01), Lindeman
Japanese Abstract No. 2-247542 A, P-1145, Dec. 20, 1990, vol. 14, No. 574 issued to Hitachi Seiki Co. Ltd.
Raevis Robert
ZF Friedrichshafen AG
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