DE102018125141B3 - Friction mating test rig for simultaneous recording of tribological and acoustic characteristics - Google Patents

Abstract

Reibpaarungsprüfstand (1) for simultaneously recording Reibungsmesswerten and noise measurements, comprising a first fastener (5) and a second fastener (6) for attaching at least one test specimen, wherein the first fastener (5) by means of at least one first drive unit (17) in exactly two spatial directions (x, y) is drivable and wherein the second fastening element (6) by means of a second drive unit (18) in exactly one further spatial direction (z) can be driven, characterized in that
these drive units (17, 18) are arranged in the air-conditioned test chamber (16) within each drive housing, which at least substantially separate the drive unit (17, 18) from the air-conditioned test room (16) and
in that at least one of the drive units (17, 18) is mounted relative to a test rig frame (2) by means of a drive bearing (15).

Description

The invention relates to a test stand for the investigation of friction pairings with respect to noise, with which in addition the tribological behavior of two specimens (friction pair) can be determined (so-called Reibpaarungsprüfstand) and a method for particularly simultaneous detection of noise and friction behavior of the moving specimens. This Reibpaarungsprüfstand and this method are intended especially for vehicle components.

So far, for the analysis of noise on vehicle components, a stick-slip test stand (or Knarzprüfstand), a test facility on a Hydropulsanlage with and without climatic environment and so-called. Shaker (vibrator) for specimens with and without climatic environment and a noise tester known. From the prior art, it is therefore known to investigate noise and friction behavior separately from each other.

The stick-slip test stand has the disadvantages that the test option is possible only in a spatial axis, the maximum excitation speed, especially for high-frequency excitation, insufficient, real motion data from the vehicle, at least in part, can not be implemented and components only can be checked restricted. The stick-slip test bench is also only intended for flat samples.

The Hydropulsanlage has the disadvantages that for testing always a complete vehicle is required, the test method high cost (personnel, energy) caused in the development process before the creation of experimental vehicles, no review is possible and the excitation is only in the z-direction.

The shaker system has the disadvantages that no low frequency excitation on the vehicle is possible, always a complete vehicle is required, the test method at high cost (personnel, energy) leads, in the development process before the creation of test vehicles, no review is possible and the suggestion only in z-direction takes place.

A disadvantage of known from the prior art, so-called noise test stands, the subjective acoustic evaluation (objective evaluation due to lack of separation of background noise / noise is not possible) and the lack of opportunity to measure friction forces on two moving components.

The publication US 2007/0 113 657 A1 describes a shaker system which has a shaker component which can move a head part in one direction along an axis. The suspension of the Shakerbauteils is designed resiliently.

The publication DE 10 2007 050 499 B4 deals with a noise tester and a method for detecting noise.

The publication DE 10 2016 004 372 A1 deals with a method and a device for testing tribological properties of materials for machining.

It is the object of the present invention to provide a possibility for simultaneous noise testing and detection of a friction behavior of a friction pairing, especially for friction pairings such as these used in vehicle application. In particular, such a possibility for noise and friction behavior test of friction pairings should be created, in particular such friction pairings on vehicles or vehicle components.

This object is achieved by means of a Reibpaarungsprüfstands according to claim 1 and a method according to claim 13. Advantageous embodiments of the invention are the subject of the dependent claims.

The Reibpaarungsprüfstand, which is in particular a Fahrzeuggeräusch- and Reibverhaltensprufstand, has a first fastener and a second fastener for attaching a test specimen, z. B. a vehicle or a vehicle component, on, wherein the first fastening element by means of at least one drive unit in exactly two directions in space is drivable or mechanically excitable and the second fastener ( 6 ) in exactly one further spatial direction ( z ) is drivable or mechanically excitable. Further preferably, the Reibpaarungsprüfstand an air-conditioned test room, in which both these fasteners for receiving the test pieces for the friction pair and the first and second drive unit are arranged. Further, at least one of these drive units, preferably both drive units, are arranged in the air-conditioned test chamber within each case of a drive housing.

In this sense, under such a drive housing to understand an enclosure for at least one of these drive units. In particular, such an enclosure is thus to be understood as a housing device which surrounds this drive unit at least partially or preferably completely, and thus forms a shielding of this drive unit with respect to the rest of the air-conditioned test space. Next is this at least one housed in a housing drive unit or preferably several and preferably all housed in housings drive units are mounted with at least one low-friction drive storage relative to a test rig and thus decoupled from the test rig frame. In this sense, the test rig frame forms in particular a base frame or a foundation for this Reibpaarungsprüfstand on which at least these drive units are arranged.

The proposed Reibpaarungsprüfstand it is possible, in particular at the same time to record friction and noise measurements and thus perform a particularly efficient measurement. A friction measurement value is to be understood in particular as force measurement quantities, preferably a force or movement measurement quantities, preferably an acceleration or a speed. A noise measurement value is preferably a sound pressure, more preferably an acceleration or a vibration frequency of a component. A measuring method / sensor as such for measuring noise or friction values is not the subject of the invention, rather such sensors and methods for recording friction measurements and noise measurements from the prior art are known.

Preferably, at least one acceleration sensor is arranged on one of the fastening elements or rigidly coupled thereto, and more preferably, a plurality of acceleration sensors are arranged directly on one or on the plurality of fastening elements.

Preferably, at least one force measuring sensor is arranged on at least one drive element of one of the drive units and preferably this sensor is arranged within the drive housing of this drive unit. In particular, by the constant conditions within the drive housing a particularly precise measurement is possible with such a sensor.

The proposed embodiment of the Reibpaarungsprüfstands the attached to the fasteners test specimen can be driven in three spatial directions, or is to be tested friction pair with realistic motion profiles claimable. This allows a realistic stress on the specimens. In addition, the fasteners can accommodate different sized and shaped specimens, which increases a Prüfflexibiliät. Since comparatively simple and safe motors can preferably be used, the test bench is also inexpensive to purchase and operate.

When recording the noise behavior of the test specimens, noise emitted by the drive units, ie in particular noise, can influence the measurement results. By enclosing at least one or preferably several of the drive units, the influence of this noise can be reduced and the measurement result can be improved. In particular, by such an embodiment, it is possible with the proposed test stand two test profiles (sealing profile and friction partners) with regard to their noise behavior, in particular for real roadway excitation, since it is replicated by the drive units to investigate.

Furthermore, it is possible, by means of such a drive housing in combination with the drive mounting, to decouple one of the drive units mechanically and thermally from the air-conditioned test space. In particular, by at least substantially frictionless drive storage is entered by this almost no heat in the housing of the drive unit. This low heat input leads in particular to the fact that the drive unit can be operated at almost constant temperature conditions, even if the temperature in the air-conditioned test room, in particular due to the test conditions, is changed. The controllability of a drive unit at a quasi-constant temperature is better than with changing temperature and thus the quality of the achievable measured values is improved. Turned another way, a combination of housing the drive unit and at least substantially frictionless drive storage not only leads to noise reduction and good mechanical decoupling, but also to improved controllability of this drive unit and thus to improve the measurement quality.

In the context of the invention, a drive element of this drive unit is to be understood as a component which is set up directly for transmitting forces to the fastening elements of the friction pairing test bench.

A movement of the test specimen in all three spatial directions gives particularly realistic test conditions. Typically, the sounds are picked up by one or more microphones and can be evaluated as follows, e.g. B. with respect to a noise level.

It is preferred if the two clamping plates formed by the fastening elements are spaced apart.

In addition, a friction pairing test stand in which the first fastening element is moved by means of two drive units is preferred, wherein each of these drive units is the first Moving fastener in a different direction in space. This supports a simple control of the Reibpaarungsprüfstands.

In addition, vibration parameters, in particular acceleration signals of vibrations that occur during a noise development, are preferably also recorded and evaluated. Particularly advantageously, the intensity of vibrations can be determined from the measured acceleration values. Here, triaxial acceleration sensors are preferably used. These may be articulated on the specimen to scan the acceleration values, or on a part of the frictional combination dynamometer whose movement is a measure of the acceleration of the specimen, e.g. on a clamping plate or an adapter. Also advantageous is a recording and evaluation unit for displaying and storing the measured values. The control can typically take place via suitable control systems.

As fasteners all known, suitable fasteners can be used, for. B. brackets, etc. For ease of use and increased flexibility, however, the fasteners preferably comprise platens (or other base support), which are adapted to receive adapter means for articulation of the test body, z. B. by providing through holes, grooves, grooves u. v. m.

Preferably, at least one of the drive units is a rotating motor, in particular a continuously variable electric motor having a downstream, preferably stepless, eccentric. This makes it possible to provide a robust, inexpensive and easy to handle drive. Further preferably, the drive unit, in particular due to the drive storage, to be considered at least substantially frictionless and in particular due to this freedom from friction simultaneous force measurement and tribology measurement is possible.

Alternatively or additionally, it may be preferred if the Reibpaarungsprüfstand has as drive unit at least one electrodynamic shaker.

Further preferably, the drive bearing is designed as a frictionless or at least substantially frictionless storage as set forth, and in particular an at least substantially frictionless drive is made possible. In particular, by the freedom of friction, the force and Tribology measurement is possible.

For further and even more flexible testing is preferably a climate cabin for receiving the specimen for controlling an ambient temperature and / or humidity on the specimen available.

It is also advantageous to provide a control unit or control and evaluation unit for controlling the drive units, by means of which at least excitation frequencies of the at least one fastening element are adjustable. For this purpose, the control unit preferably has a memory in which load (motion, temperature, etc.) - profiles for test bed control can be stored.

The method is used in particular for detecting noises and frequencies, that is to say in particular for detecting the tribological behavior and forces, of at least one moving test body, in particular of vehicles or vehicle components, and has at least the following steps: articulation of the test body to two fastening elements, moving of the Test specimen in three spatial directions and recording noises of the specimen.

The method comprises the following steps: articulation of the test specimen to two fasteners and moving the test specimen in three spatial directions by moving a fastener in exactly two spatial directions and moving another fastener in exactly one other spatial direction.

Further preferably, it is possible to block one or more axes or drive units of the Reibpaarungsprüfstands, preferably to lock. In particular, this blocking allows u.a. the simulation of rigid connections / couplings and the influence analysis of individual / paired directions of excitation.

In a further preferred embodiment of the measuring method, the Reibpaarungsprüfstand is operated with a load collective, or this, for the friction pair to be tested, a load spectrum according to how this, preferably on the basis of measured values from a vehicle or preferably under real conditions, determined. Further preferably, it is possible firstly to simulate acceleration-controlled signals (high-frequency, stochastic, directly from the relevant vehicle measuring point) with the friction pairing test stand and secondly position-controlled signals (low-frequency, synthetic, for example sine) for analysis purposes with defined conditions (for example measurement of Stribeck curves). In particular, these different possibilities of controlling the Reibpaarungsprüfstands results in a variety of analysis options. In particular, by means of such a realistic load collective particularly good and relevant measurement results can be achieved.

• 1 zeigt in Schrägansicht einen Reibpaarungsprüfstand;
• 2 zeigt den Reibpaarungsprüfstand aus 1 in einer weiteren Schrägansicht mit eingezeichneten Bewegungsrichtungen der Motoren und Befestigungselemente;
• 3 zeigt den Geräuschprüfstand aus 1 in noch einer weiteren Schrägansicht ebenfalls mit eingezeichneten Bewegungsrichtungen.
• 4 zeigt eine schematisierte Ansicht des Reibpaarungsprüfstands mit Einhausungen für die Antriebseinheiten, reibungsarmer Lagerung für diese und klimatisierbaren Prüfraum.

The invention will be described in more detail schematically with reference to the following schematic embodiment, in which show the 1 to 3 a possible mechanical structure of such Reibpaarungsprüfstands, not shown in these figures, the drive housing for the drive units, their low-friction storage and the air-conditioned test room, said features in 4 are shown in full.

• 1 shows an oblique view of a Reibpaarungsprüfstand;
• 2 shows the Reibpaarungsprüfstand 1 in a further oblique view with marked directions of movement of the motors and fasteners;
• 3 shows the noise tester 1 in yet another oblique view also with marked directions of movement.
• 4 shows a schematic view of the Reibpaarungsprüfstands with housings for the drive units, low-friction storage for this and air-conditioned test room.

The figures show a noise tester 1 with a bottom plate 2 on which spaced two pedestals 3 . 4 are attached. At each of the pedestals 3 . 4 is in each case a clamping plate 5 . 6 mounted, which is arranged by means of bore and longitudinal holes (without reference numerals) for attachment of adapters.

One of the platens that with 5 is designated by means of two rotating, continuously variable electric motors 7 . 8th movable parallel to its surface, ie, in an (x, y) plane. In addition this clamping plate is 5 via a respective stepless eccentric 9 . 10 at spaced locations on the electric motors 7 . 8th hinged. In detail, a rotary motion of the electric motor 7 by means of the eccentric 9 in a linear pendulum motion of a push rod 11 converted along the x-axis. The push rod 11 is a bolt (without reference numeral) with the displaceably mounted in the x-direction platen 5 connected so that also the platen 5 performs a pendulum movement in the x direction. Analog is a rotary motion of the electric motor 8th by means of the eccentric 10 in a linear pendulum motion of a push rod 12 converted along the y-axis. The push rod 12 is with the also displaceably mounted in the y-direction platen 5 connected so that also the platen 5 performs a pendulum motion in the y-direction. Overall, the platen can be 5 through the engines 7 . 8th move in the (x, y) plane. The first platen 5 opposite second clamping plate 6 is held elastically in the (x, y) plane to avoid distortion of the specimen.

The second clamping plate 6 is, however, by means of only one electric motor 13 driven, whose rotational movement by means of an eccentric 14 in a linear pendulum motion of a push rod 15 converted along the z-axis. The push rod 15 is with the displaceably mounted in the z-direction platen 6 connected so that also the platen 6 performs a pendulum movement in the z-direction. The first clamping plate 5 is held elastically in the z-direction to avoid distortion of the specimen.

The directions of movement are determined by the in 2 and 3 symbolized arrows symbolizes. Overall, the clamping plates 5 . 6 be moved in the three spatial axes up to a maximum of ± 3 mm. To achieve these dimensions of movement are play-free guides and the stepless eccentric 9 . 10 . 14 used.

A test specimen (not shown, eg a vehicle or a vehicle component) can be directly or via respective adapters (not shown) on the clamping plates 5 . 6 be attached. Upon actuation of the electric motors 7 . 8th . 13 is moved, depending on the set movement, the specimen.

Present, but not shown for clarity, is also at least one microphone for recording the noise generated by the specimen, in particular a field of multiple microphones, as is known in particular to the expert.

In addition, a climate cabin for the test specimen can be installed on the test bench so that an ambient temperature and humidity can be set and recorded.
The test stand can furthermore have at least one connection for a temperature sensor, if appropriate also the at least one temperature sensor, by means of which a surface temperature of the test body can be scanned.

The movement sequence can be set on a control unit (not shown) and stored as a program or program parameter. The control unit has for this purpose a memory for storing various predetermined stress profiles, which comprise at least the movement sequences of the clamping plates, possibly also other factors such as temperature or humidity. These stress profiles can, for example, be imported from vehicle trials. The program parameters can z. B. be varied for comparison tests. By means of the control unit also serving as an evaluation unit, or by means of an independent evaluation system, for example, in addition to the sensor values described above, the excitation frequencies, the respective path of the Clamping plates and their acceleration are recorded as parameters of a noise assessment.

By means of the test stand described, the test body can be acted upon in a compact design with suggestions or movements that realistically imitate a real operation, especially driving. Because this allows a three-dimensional movement of specimens, which simulates the real expected relative movements. As a result, with this test unit any noise can be effectively displayed.

Of course, the present invention is not limited to the embodiment shown. Alternatively, instead of the electric motors and the eccentric are, for example, electrodynamic shakers, these are preferred, or mechanically or hydraulically amplified piezoelectric actuators used.

By means of the proposed Reibpaarungsprüfstands it is possible not only impart the excitation movement on the specimens one-dimensional, but different drive directions are possible. The drive directions need not be substantially orthogonal to each other, but may have any non-collinear angular relationship, although this is not preferred. Also, more than one motor for movement in a spatial direction are conceivable. The platens also need not be directly opposite, nor is the invention also limited to two fasteners. Also, other fasteners may be used as platens.

2 shows the schematized Reibpaarungsprüfstand 1 with test rig frame 2 and air-conditioned test room 16 , Inside the air-conditioned test room 16 Within certain limit values, any climatic conditions can be set, and among these, then, the fastening elements 5 . 6 recorded friction pair are tested. With the first and second drive unit 17 . 18 be applied to this friction pair, the load collective, this can be modeled, for example, measured on a motor vehicle sizes. The first drive unit 17 is in the housing designed as a first drive housing 23 recorded and opposite the air-conditioned test room 16 separated.

The first drive unit 17 is in front of the test rig 2 with a drive storage 25 decoupled. The second drive unit 18 is opposite the test rig frame 2 with a drive storage 25 decoupled. These drive bearings are essentially designed as frictionless bearings.

Because of the drive units 17 . 18 are housed opposite the klimatisierbren test space is an operation possible at almost constant conditions and thus is a particularly precise control of these drive units 17 . 18 reachable.

To record noise and friction measurements on the friction pair to be examined are acceleration sensors 19 directly to the fasteners 5 . 6 and force sensors 20 on the drive units 17 . 18 intended.

In 4 the Reibpaarungsprüfstand is schematized but shown in full. On the test rig rack 2 is the air-conditioned test room 16 arranged. In the air-conditioned test room 16 is the enclosure 23 with the first drive unit 17 and the enclosure 24 with the second drive unit 24 arranged, these enclosures 23 . 24 separate the drive units 23 . 24 in or from the air-conditioned test room 16 from.

With the first drive unit 23 , which about the drive bearings 25 is stored almost frictionless, is the platen 5 drivable. With the second drive unit 18 is the clamping plate 6 drivable. Also the electric motor 13 the second drive unit 18 is about a virtually frictionless drive storage 25 stored, like the electric motor 7 and 8th the first drive unit 17 , Over the air-permeable membrane 26 can vent the enclosures 23 . 24 respectively.

The drive units 17 . 18 are on the sockets 3 . 4 arranged. To measure the accelerations on the specimens (not shown) are the acceleration sensors 19 provided and on the clamping plates 5 . 6 arranged. Next are force sensors for measuring the driving forces 20 on the drive units 17 . 18 intended. About the electric motors 7 . 8th . 13 are with the drive units 17 . 18 the directions of movement 28 . 29 . 30 produced.

In other words, the proposed friction mating test rig enables the synchronous measurement of acoustic and tribological characteristics for a friction mating.

This possibility for synchronous measurement on a friction pair to be tested is made possible by a, at least almost, frictionless drive of the Reibpaarungsprüfstands, which is achieved in particular by a shaker as a drive in combination with the drive storage. In particular, the proposed concept of Reibpaarungsprüfstands the three-dimensional measurement of friction forces on 2 moving test parts (friction pairing). In test bench concepts known from the prior art, the frictional force is determined, for example, by means of the deflection of a spring on one of the test parts or on a holder for this test part; this type of measurement requires the rest position of the test part. The virtually frictionless drive of the proposed Reibpaarungsprüfstand allows in contrast, the force measurement of two simultaneously moving test parts (friction pair) and thus a realistic recording of tribological measurements.

In particular, for the simultaneous or synchronous determination of acoustic and tribological measurements, it is advantageous to isolate or reduce noise, as they can be caused by the drive units. In particular, to reduce the noise from the drive units, an enclosure of these is provided in a so-called drive housing.

By combining an at least almost frictionless drive storage with an enclosure (drive housing), there is the positive effect that a test procedure in the air-conditioned test room in a wide climate range (minus 30 ° C to plus 80 ° C, changing relative humidity, etc. ) is feasible, since with the above combination (drive housing, drive storage) is prevented that the drive unit is exposed to prevailing in the air-conditioned test room conditions (temperature, humidity).

Furthermore, it is possible by the described separation of drive housing to air-conditioned test room to use a measuring system in a space (drive housing) with limited interior space.

Furthermore, it is possible to extend the test stand by further degrees of freedom of movement and thus also to investigate torsion and / or moment loads on the friction pairing.

In particular, by the separation of excitation frequencies, as these are applied by the one or more drive units, and stick-slip frequencies, as they can arise at the friction pair, the detection of stick-slip effects and the evaluation with objective characteristics is possible. Further preferably, a low-pass filtering 60 Hz (excitation) and a high-pass filtering 80-100 Hz (stick-slip) is provided for the investigation of stochastic signals. Further preferably, a low-pass filtering of 10 Hz (excitation) and a high-pass filtering of 30 Hz (stick-slip) are provided for the examination of sine signals.

LIST OF REFERENCE NUMBERS

1

Reibpaarungsprüfstand

2

Base plate / test rig frame

3

base

4

base

5

platen

6

platen

7

electric motor

8th

electric motor

13

electric motor

16

air-conditioned test room

17

first drive unit

18

second drive unit

19

accelerometer

20

force sensor

23

Enclosure of 17

24

Enclosure of 18

25

Drive storage

26

Air permeable membrane

27

Movement directions of the drives

28

Direction of movement drive unit first drive unit

29

Direction of movement drive unit first drive unit

30

Direction of movement drive unit second drive unit

Claims (13)

Reibpaarungsprüfstand (1) for simultaneously recording Reibungsmesswerten and noise measurements, comprising a first fastener (5) and a second fastener (6) for attaching at least one test specimen, wherein the first fastener (5) by means of at least one first drive unit (17) in exactly two spatial directions (x, y) can be driven and wherein the second fastening element (6) can be driven in exactly one further spatial direction (z) by means of a second drive unit (18), characterized in that these drive units (17, 18) in the air-conditioned test room ( 16) are arranged within each drive housing, which at least substantially separate the drive unit (17, 18) from the air-conditioned test room (16) and that at least one of the drive units (17, 18) by means of a drive bearing (15) opposite a test rig frame (2) is mounted. Reibpaarungsprüfstand after Claim 1 , characterized in that an air-conditioned test space is provided, in which both these fastening elements (5, 6) and these first and second drive unit (17, 18) are arranged. Reibpaarungsprüfstand according to any one of the preceding claims, characterized in that the at least one drive bearing (25) is designed as at least substantially frictionless storage. Reibpaarungsprüfstand (1) according to any one of the preceding claims, wherein the two spatial directions (x, y), in which the first fastening element (5) is drivable, perpendicular to each other, and wherein the further spatial direction (z), in which the second fastening element ( 6) is drivable, perpendicular to the two spatial directions (x, y) runs. Reibpaarungsprüfstand (1) according to any one of the preceding claims, wherein the first fastening element (7) by means of two drive units (7, 9, 8, 10) is drivable, wherein each of these drive units (7, 9, 8, 10), the first fastening element ( 7) moves in another spatial direction (x; y). Reibpaarungsprüfstand (1) after one of Claims 1 to 3 in which the fastening elements comprise clamping plates (5, 6) which are set up to receive an adapter means for articulating the test body. Reibpaarungsprüfstand (1) according to any one of the preceding claims, wherein at least one of the drive units (17, 18) has a rotating motor (7, 8, 13) with a respective downstream eccentric (9, 10, 14). Reibpaarungsprüfstand according to any one of the preceding claims, wherein at least one of the drive units (17, 18) has an electrodynamic shaker. Friction mating test stand (1) to Claim 8 , characterized in that all of the drive units (17, 18) are designed as electrodynamic shakers. Reibpaarungsprüfstand according to any one of the preceding claims, further comprising at least one acceleration sensor (19) for sensing acceleration values of the test body, wherein said at least one acceleration sensor (19) on one of the fastening elements (5, 6) is arranged or rigidly coupled thereto. Reibpaarungsprüfstand according to any one of the preceding claims, further comprising at least one force sensor (20) for sensing force values of at least one of the drive units (17, 18), said at least one force sensor (20) on a drive element of said drive unit (17, 18) is arranged. Reibpaarungsprüfstand according to one of the preceding claims, wherein this is designed for vehicle noise test. A method of detecting noise and friction measurements with a friction mating tester according to any one of the preceding claims, comprising the following steps: Articulation of the friction pair on two fastening elements (5, 6), Moving the test specimens in three spatial directions to one another by moving a first fastening element (5) in exactly two spatial directions (x, y) and moving a second fastening element (6) in exactly one further spatial direction (z), and - Recording of noise and Reibungsmessgrößen the test specimen.

Images