WO2006034929A1

WO2006034929A1 - Device for tribiologically testing a test piece in a pressure chamber pressurized with overpressure

Info

Publication number: WO2006034929A1
Application number: PCT/EP2005/054101
Authority: WO
Inventors: Klaus Meyer; Gernot Repphun
Original assignee: Robert Bosch Gmbh
Priority date: 2004-09-29
Filing date: 2005-08-19
Publication date: 2006-04-06
Also published as: DE102004047106A1

Abstract

The invention relates to a device for tribiologically testing a test piece (3), comprising, as a basic components, a holding device (6) for holding the test piece (3), a drive device (2) for producing a relative motion between the test piece (3) and a counter body (30), a load generating device (9) for applying a predetermined load to the test piece (3), and a supply device (12) for supplying a lubricating medium. A pressure chamber (15) pressurized with overpressure is provided as the testing environment, and the test piece (3) can be placed inside this pressure chamber while being located on the holding device (6) and actively connected to the other basic components (2, 9).

Description

DEVICE FOR THE TRIBOLOGICAL TESTING OF A TEST BODY IN A PRESSURE CHAMBER HAVING OVERPRESSURE

State of the art

The present invention relates to a device for tribological testing of a test specimen according to the closer in the preamble of claim 1. Art.

In practice, devices for testing for friction, lubrication and wear are known as so-called tribometers, with which the friction and wear behavior of test specimens is investigated. For use such Tribometer z. B. in the wear test of components for

High-pressure injection systems in diesel and gasoline engines, hydraulic units, piston and gear pumps or the like. It is called the load of a component to be tested with a real load collective, which is in the final product in the application.

For tribological testing of the specimen and a corresponding counter body is moved under load possibly with a lubricating medium under conditions of use relative to each other or relative to the medium. As movements are z. B. a particular reversing sliding, rolling, hitting or the like provided. In the process, important parameters such as wear, frictional force, temperature etc. are evaluated. The known devices operate at atmospheric pressure and ambient conditions, the environmental conditions, where appropriate, with respect to certain parameters, such as. As the humidity, conditioned.

It has been shown that when using volatile, liquid lubricating media or when using liquid lubricating media above the boiling point, an evaporation of the lubricating medium takes place. Even if counteracted by a permanent supply of the lubricating medium, there is the problem that during the tribological contact between the test specimen and the counter body, a transition can occur in the vapor phase, associated with blistering.

In addition, a change in the chemical composition of the mixture may occur in the case of a mixture of different fluids as a lubricant mixture mixture, since hardly volatile components accumulate.

Accordingly, the present invention seeks to propose a device of the type mentioned, which prevents evaporation of the lubricating medium in a tribological test with real load collectives and at the same time the use of easily combustible and explosive media is also possible.

Advantages of the invention

The invention provides a device for tribological testing of a test specimen, comprising as base components a holding device for holding the test specimen, a drive device for generating a relative movement between the specimen and a counter body, a Load generating device for applying a predetermined load on the test specimen, and a feed device for supplying a lubricating medium, wherein the device is designed such that a pressure chamber can be acted upon pressure chamber is provided as the test environment, in which the test specimen on the holding device and in operative connection with the other basic components can be arranged.

If a part or all basic components of the device according to the invention for tribological testing are housed in the pressure chamber, so can advantageously the vapor pressure of the z. B. liquid lubricant can be compensated by the variable internal pressure in the pressure chamber and evaporation of the lubricant can be minimized.

Furthermore, with the device according to the invention for tribological testing advantageously the formation of an explosive gas-air mixture can be prevented, wherein the pressure chamber for reducing the content of oxygen, in which vapors of a combustible medium can distribute, for. B. can be completely filled with liquid and the use of nitrogen or carbon dioxide to fill a non-liquid occupied volume of the interior of the pressure chamber is possible.

The device according to the invention thus represents a tribometer, which is designed to test each type of test specimen under real load spectra, ie its load when used in the product. It has been found that the proposed device is particularly suitable for the tribological testing of high-pressure generating components, in particular in motor vehicles. Since even the highest explosion protection requirements can be met by the proposed device, the use of easily combustible media is possible. Hereby, the device according to the invention is also suitable for testing of and with operating materials, in particular media for

Internal combustion engines. Model test specimens and original components of diesel and petrol high-pressure injection pumps and injectors can be optimized with regard to the materials used and the behavior in fuels such. As gasoline fuels, diesel or fuels for aircraft turbines, be investigated and determined.

According to one embodiment of the present invention can be provided that all basic components of the device according to the invention, d. H. in particular, the holding device, the drive device and the load generating device, are arranged in the sealed pressure chamber.

In such a configuration advantageously only electrical leads into the pressure chamber and hydraulic drive additional hydraulic lines are needed. Further, consuming sealed openings in the container wall of the pressure chamber for performing parts of the base components can be omitted, making the total sealing of the pressure chamber is very easy and inexpensive to implement.

In order to detect certain parameters, in particular wear-dependent parameters or the like, during the tribological test, according to a further embodiment of the present invention, a sensor device, such. B. a force sensor, be provided in the interior of the pressure chamber. In an advantageous embodiment, the test body can be coupled to the holding device via the force sensor in such an embodiment. Thus, the simplest possible detection z. B. allows a friction force occurring in a wear test.

Another, particularly favorable variant of the present invention can provide that certain basic components or other components, preferably components with sensitive electronic devices, are arranged outside the pressure chamber, so that any necessary protective measures, eg. B. to protect against contact with the lubricating medium, before entering the corresponding component or to meet explosion protection requirements, can be omitted in the aforementioned components.

Under these aspects, it may be particularly expedient to arrange the drive device and the load generating device and sensitive sensors outside the pressure chamber.

In order to realize an optimal sealing of the pressure chamber in the above-described variant of the present invention, may be provided according to a next development that the motion transmission path of the drive device and the load transmission path of the

Load generating device are guided in each case with a sealed passage in the interior of the pressure chamber. In this case, special, sealing bearings can be used in the motion transmission path and also in the load transmission path, so that a

Seal can be ensured to over 10 bar internal pressure in the pressure chamber. A further embodiment of the invention provides that the drive device comprises an electric motor or the like, wherein a motion transmission path can be provided in which a rotational movement of the electric motor is preferably converted via an eccentric and a lifting rod in an approximately linear movement. Thus, the test specimen and the counter body can be moved relatively linearly to each other or to the lubricating medium.

Alternatively, however, other drives and other types of movement of a continuous, discontinuous, linear, rotary or oscillating relative motion may find application.

For load introduction can be provided that the

Load generating device comprises a Spindelhubgetriebe or the like, which is coupled to a power piston which acts on the holding body with a predetermined force on the test body or the counter body. In this case, a normal force in the order of z. B. 10,000 N or less or higher. However, other elements are conceivable in order to realize the load introduction path and to transmit the force to the test specimen.

A sensor device for detecting z. B. wear-dependent parameters, which may be conveniently located outside the pressure chamber is z .B. a force sensor which has a rod element or other transfer means for detecting a friction force, normal force and / or lubricant gap width occurring on the test specimen. The rod member can be guided through a specially sealed storage through a passage of a container wall of the pressure chamber, so that no pressure loss through a leakage in the passage through the pressure chamber wall may occur.

Depending on the type of sensor devices used, a part of the sensor elements which are not resistant to the medium in the pressure chamber or which are not explosion-proof can also be arranged outside the pressure chamber and a part of correspondingly protected sensor elements can be arranged inside the pressure chamber.

A possible embodiment of the present invention may further provide a tempering device arranged in particular on the holding device for tempering the test body and / or the medium. In this way, the interior of the pressure chamber and the test specimen can be heated or cooled.

If the tempering device serves as a heater, which z. B. is equipped with a heating cartridge or the like, this is suitably designed so that media temperatures of about 250 ° C or lower or higher in the pressure chamber of the device according to the invention are readily possible.

Further advantages and advantageous embodiments of the article according to the invention are the description, the drawings and the claims removed.

drawing

Hereinafter, the present invention will be explained in detail with reference to the drawings. Show it

Figure 1 is a schematic three-dimensional view of an advantageous embodiment of a device according to the invention for tribological testing;

Figure 2 is a sectional partial view of Figure 1; and Figure 3 is a block diagram of the device according to the invention.

Description of the embodiment

FIGS. 1 to 3 schematically show a device 1 according to the invention for tribological testing of a test specimen, which is held on a table-like frame 10.

The device 1 has a drive device 2 which comprises an electric motor 20 whose rotational movements are transmitted via a motion transmission path to a counter body 30 to be moved relative to a test body 3. The motion transmission path is provided with an eccentric 4 and a lifting rod 5, whereby an approximately linear movement is transmitted to the test body 3. In the embodiment shown, the drive device 2 at a frequency of about <100 Hz cause an amplitude of ≤lOmm on the test piece 3.

Furthermore, a holding device 6 for holding the test body 3 and the counter body 30 is provided. The holding device 6 is shown in more detail in particular in Figures 2 and 3 and has an upper Prüfkörperaufnähme 7 and a lower Prüfkörperaufnähme 8. To transmit the movement of the lifting rod 5 on the test specimen 3, the lifting rod 5 is coupled to the upper Prüfkörperaufnähme 7.

For applying a predetermined load on the test specimen 3 or the counter body 30 for wear testing, a load generating device 9 is provided as a further component. The load generating device 9 comprises a screw jack 31, which is coupled to a power piston 11, which is a Normal force of about 10,000 N on the holding device 6 applies. For this purpose, the power piston 11 is in turn coupled to the holding device 6, so that z. B. is held by the holding device 6 counter body 30 is acted upon by the predetermined force.

The test body 3 and the counter body 30 are arranged with the holding device 6 in a test chamber forming the test environment 15. For supplying an operating medium or lubricating medium, an opening into the pressure chamber 15 feeder 12 is provided.

As can be seen in particular from Figure 3, the feeder 12 z. B. from a container 13, the lubricating medium via a diaphragm pump 14 in the intended as a test environment pressure chamber 15 perform. As also shown in Figure 3, the diaphragm pump 14 may be followed by a check valve 16, a medium filter 17 and a 2-way ball valve 18, wherein the arrangement order can be varied.

According to the invention, in the embodiment illustrated in particular in FIGS. 1 and 2, all sensitive components, such as the drive drive device 2, the load generating device 9 and certain sensor devices are provided outside the pressure chamber 15, while not further designated, protected sensor devices are arranged at least partially in the pressure chamber 15 ,

The motion transmission path of the drive device 2 and the load transmission path of the load generating device 9 are each guided via specially sealed passages into the interior of the pressure chamber 15. FIG. 3 shows from the basic diagram that a force sensor 19 is provided at least partially in the interior of the pressure chamber 15. The force sensor 19 serves in this way as a coupling member between a power piston 11 of the load generating device 9 and the holding device. 6

The coupled to the Spindelhubgetriebe 31 power piston 11 of the load generating device 9 has for temperature control, in particular of the test specimen 3, a tempering device 32 in the form of a heating cartridge and a temperature sensor 21 for controlling the temperature.

Furthermore, a cleaning drain 22 is provided on the power piston 11 for discharging the medium located in the pressure chamber 15, wherein the cleaning drain 22 connects the pressure chamber 15 with a collecting container 23. In order to regulate the discharging medium flow, a 3-way ball valve 24 and an overflow valve 25 are provided in the cleaning outlet 22 in the present case.

As can be seen from FIG. 3, the

Motion transmission path of the drive device 1 in the region of the lifting rod 5, a vibration measuring system 26 for detecting the amplitude of the lifting rod 5 have.

In addition to the cleaning outlet 22 may also be provided a cleaning supply line 27 for the pressure chamber 15, through which a cleaning medium can flow into the pressure chamber 15, wherein the cleaning supply line 27 also has a valve 28 for better regulation of the incoming cleaning medium.

In the embodiment shown, the sensor device further comprises a pressure sensor 29 for sensing the internal pressure arranged outside the pressure chamber 15, wherein the sensor is guided into the pressure chamber 15.

For filling the pressure chamber 15, a nitrogen container 33 is further connected via a check valve 34 and a further valve 35 to the interior of the pressure chamber 15. In this way, at a high oxygen content flooding of the pressure chamber 15 with z. As nitrogen can be realized, wherein the oxygen content is measured continuously by an oxygen sensor 36. The oxygen sensor 36 may include a sensor, which is also located in the interior of the pressure chamber 15.

The device 1 shown for tribological testing of the test specimen 3 is in the figures as so-called

Trained Hochtemperaturschwingungsverschleißprüfstand on which in particular high-pressure generating components of internal combustion engines can be tested.

Claims

claims

1. A device for tribological testing of a test specimen (3), comprising as base components a holding device (6) for holding the test specimen (3), a drive device (2) for generating a relative movement between the specimen (3) and a counter body (30), a load generating device (9) for applying a predetermined load to the test body (3), and a feed device (12) for supplying a lubricating medium, characterized in that a pressure chamber (15) which can be pressurized with overpressure is provided as test environment, in which the test body (15) 3) on the holding device (6) and in operative connection with the further base components (2, 9) can be arranged.

2. Apparatus according to claim 1, characterized in that all the base components (2, 6, 9) in the sealed pressure chamber (15) are arranged.

3. Apparatus according to claim 1 or 2, characterized in that at least one force sensor (19) is at least partially provided in the interior of the pressure chamber (15) as a sensor device, wherein the test body (3) via the force sensor (19) with the holding device (6 ) is coupled.

4. Apparatus according to claim 1, characterized in that at least the drive means (2) and the load generating means (9) are arranged substantially outside of the pressure chamber (15).

5. Apparatus according to claim 4, characterized in that a movement transmission path of the drive device (2) and a load transmission path of the load generating device

(9) are guided in each case by means of a sealed passage in the interior of the pressure chamber (15).

6. The device according to claim 5, characterized in that the drive device (2) comprises an electric motor (20) whose rotational movement via an eccentric (4) and a lifting rod (5) as a motion transmission path in an at least approximately linear motion is convertible.

7. Apparatus according to claim 5 or 6, characterized in that the load generating device (9) comprises a screw jack (31) which is coupled to a power piston (11) which acts on the holding device (6) with a predetermined force.

8. Device according to one of claims 4 to 7, characterized in that sensor means for detecting wear-dependent parameters outside the pressure chamber (15) are arranged.

9. Apparatus according to claim 8, characterized in that a force sensor arranged outside the pressure chamber (15) is provided as the sensor device, which has a rod element for detecting the friction force occurring on the test body.

10. The device according to claim 9, characterized in that the rod element from the pressure chamber (15) is guided over a reibarmabgedichtete implementation.

11. Device according to one of claims 4 to 10, characterized in that explosion-proof sensor devices are arranged within the pressure chamber (15).

12. Device according to one of the preceding claims, characterized in that a particular on the

Holding device (6) arranged tempering device (32) for controlling the temperature of the test body (3) and / or the medium is provided.