WO2008052890A2

WO2008052890A2 - Mechanical device with lubricant sensor for lubricant-quantity-independent property of the lubricant

Info

Publication number: WO2008052890A2
Application number: PCT/EP2007/061163
Authority: WO
Inventors: Norbert WÖHNER
Original assignee: Siemens Aktiengesellschaft
Priority date: 2006-10-31
Filing date: 2007-10-18
Publication date: 2008-05-08
Also published as: DE102006051441B4; WO2008052890A3; DE102006051441A1

Abstract

A mechanical device has a base body (1) and at least one element (2) which is mounted in at least one bearing (3) so as to be movable relative to the base body (1). The bearing (3) is lubricated by means of a lubricant. Arranged on or in the base body (1) is a sensor device (5) which has at least one lubricant sensor (6) which is arranged in the vicinity of the bearing (3) and is in contact with the lubricant. At least one first electric variable, which is characteristic of a first lubricant-quantity-independent property of the lubricant, can be determined by the lubricant sensor (6). The sensor device (5) can output at least one first signal which is dependent on the first electric variable.

Description

description

Mechanical device with lubricant sensor for lubricant quantity-independent property of the lubricant

The present invention relates to a mechanical Einrich ^¬ tion with a basic body and at least one with respect to the basic body in at least one bearing movably mounted element, wherein the bearing is lubricated by means of a lubricant.

Such devices are well known. They include, for example, internal combustion engines such as gasoline engines, diesel engines, gas turbines or jet engines. They also include electrical machines such as rotary electric generators or rotary and linear electric drives. Furthermore, they include facilities without their own drive, such as pumps for water or Hydraulikol and transmission.

The bearings of movably mounted elements must be regularly checked and maintained due to the high thermal and mechanical loads occurring in the bearings. Especially this problem occurs in elektπ- see machines. In particular, the maintenance usually includes re-lubrication of the bearings, so that a used lubricant (grease or oil) is replaced with new one. Such relubrication is required in relatively short time periods, for example, every 4000 hours.

Maintenance of the machine must be carried out on site. It is therefore cumbersome, expensive and error-prone. If maintenance is not carried out or carried out too late, there is the risk of bearing damage, which in extreme cases can result in a standstill of an entire system.

In the prior art usually a bearing life and Nachschmierfπsten be specified. The specifications are based on scientific findings and empirical values. In particular, the Nachschmierfπsten must be time ^¬ Lich determined so that in all possible use cases sufficient reserves of the lubrication system are available. The technically possible service life of the lubrication system is therefore not exploited. Nevertheless, due to unusual heaps of abnormal operating conditions, a bearing may fail during operation before the next relubrication cycle.

In order to detect bearing damage early, bearing sensors are used in the prior art. The bearing sensors can record, for example, a vibration behavior and detect damage relatively early by suitable evaluation. At least a Vorschadigung the storage but has already occurred when such a change in the vibration behavior has occurred.

In the prior art it is furthermore known to detect bearing currents flowing through the bearings in electrical machines and to conclude that damage has been caused on an evaluation based thereon. Also in this process damage the camp has already occurred when the sensor responds ^¬.

Since there is already a damage to the storage in the prior art, when the sensor responds, an exchange of the bearing is usually required.

The object of the present invention is to provide a

Possibility to create by means of which changes in the lubrication state of bearings can be detected so early that no bearing damage has occurred when the sensor responds.

The object is achieved by a mechanical device having the features of claim 1. According to the invention there is arranged a Sensorein ^¬ direction on or in the base body, at least one arranged in the vicinity of La ^¬ gers, has in contact with the lubricant the lubricant sensor. At least one first electrical quantity, which is characteristic of a first lubricant quantity-independent property of the lubricant, can be determined by the lubricant sensor. Of the sensor device at least one dependent on the first Large first signal can be output.

In a first possible embodiment, the sensor determines the first electrical quantity by a chemical analysis of the lubricant. For example, the sensor can determine the water content in the lubricant, the proportion of metal particles in the lubricant, the proportion of, for example, oil in the lubricating grease or the proportion to which the lubricant is oxidized. It is also possible to determine a plurality of lubricant-medium-independent properties of the lubricant.

In a second possible embodiment, the sensor can determine the first electrical quantity by a physical analysis of the lubricant. For example, the sensor can determine the electrical conductivity, a characteristic breakdown voltage, an optical transparency, a refractive index, a density, etc. of the lubricant. Again, the determination of one of the ge ^¬ called properties, or the detection of several of the properties mentioned is alternatively possible.

The two approaches can also be combined with each other, be it in the form of a single sensor that performs both types of analyzes, be it in the form of two sensors, with one sensor performing a chemical or a physical analysis of the lubricant. In this case, it is alternatively possible for the first signal, which can be output by the sensor device, to be dependent on both electrical quantities or to be separated from the sensor device by two. different signals are output, each of which depends on one of each of the two electrical variables.

It is possible that the sensor device does not carry out any further processing of the first electrical variables. In this case, the first signal corresponds to the first electrical quantity. For example, the output signal may be a direct measure of breakdown voltage or water content.

Alternatively, it is possible for the sensor device to have an evaluation device connected to the at least one sensor, from which information about the mechanical connection as such can be determined as a function of the first electrical quantity, and that the first signal is provided with the information about the sensor mechanical device as such corresponds. For example, a pure binary signal indicative of an alarm condition may be issued. It can also be displayed, for example, to what proportion (in percentage or in time) the lubricant is consumed or when (in terms of percentage or time) the next lubricant change should take place. Combinations of such issues are possible.

The sensor device may have a number of interfaces.

By way of example, the sensor device can have a human-machine interface via which the first signal (and optionally also further signals) can be output to a human.

The output of the first signal (and possibly further signals) can take place permanently or cyclically or periodically. Alternatively, it is possible for the sensor device to be able to predetermine a polling command for retrieving the first signal from the human via the human-machine interface. Alternatively or additionally, the sensor device may comprise a power supply interface for supplying the Sensorein ^¬ direction by having outside of the mechanical device with electrical energy.

Alternatively or additionally, the sensor device may have a data interface, via which the first signal (and optionally further signals) can be output to a device-external processing unit.

The outputting to the device-external processing unit can-analogously to the output via the man-machine interface-take place permanently or cyclically or periodically. However, it is also possible that the sensor device from the processing unit via the data interface, a retrieval command for retrieving the first signal (and optionally further signals) can be predetermined.

Again alternatively or additionally, the sensor unit may have a programming interface via which the

Sensor device is programmable. The programming may, for example, include writing reference values for the at least one lubricant-quantity-independent property into a memory of the sensor device. Alternatively or additionally, the programming may comprise activating and / or deactivating reference values written in the memory.

With the exception of the human-machine interface, the interfaces can be designed as contactless interfaces. For example, they can be designed as capacitive or inductive interfaces, as radio interfaces, as ultrasonic interfaces or as infrared interfaces.

The storage of reference values in the sensor device does not necessarily have to be done by programming. For example, it is also possible that the sensor Depending on a state signal, values can be stored as reference values that are characteristic of a first electrical quantity determined by the lubricant sensor at this point in time. For example, the sensor device can be given a reset signal, on the basis of which the values are stored. Alternatively, the sensor device can be programmed such that it checks whether currently stored reference values have a predetermined value (for example, all are zero). In this case (and only then) the storage of values takes place in this embodiment.

The determination of lubricant-quantity-independent properties can be supplemented as required by recording and determining further properties. On the one hand, this may be a lubricant-dependent property. Such detection devices are generally known as oil level sensors for internal combustion engines. On the other hand, these may be lubricant-independent properties of the mechanical device. For example, an acoustic signal can be detected, which is frequency-analyzed. Also, temperatures, load cycles, field strengths of permanent magnets, humidity in the inside air of the mechanical device, vibrations, operating data, etc. can be detected. Depending on the extent of the additional detection, a more or less complete monitoring of the mechanical device is possible.

Further advantages and details emerge from the following description of an exemplary embodiment in conjunction with the drawings. In a schematic representation:

1 shows a rough sketch of a mechanical according to the invention

2, a bearing with a lubricant sensor, FIG. 3, a sensor device, FIG.

4 shows a sensor device and its interfaces, and FIG. 5 shows a possible flowchart. According to FIG 1 is a mechanical device - purely by way of example ^¬ - designed as a rotary electric machine. The electric machine has a base body 1 and a shaft 2. The shaft 2 is mounted in bearings 3, so that it is rotatable about a shaft axis 4. The shaft 2 thus corresponds to a movably supported element 2 in accordance with the present ^¬ the invention.

The bearings 3 are lubricated by means of a lubricant, not shown, (for example, a lubricating oil or a lubricating grease ^¬ ). The lubricant has in a new, unused condition certain physical and chemical properties. For example, the lubricant contains a certain amount of lubricating oil, generally no metal particles and little or no water. Also the

Oxidation of the lubricant is relatively low. In the case of a grease, this has a predetermined Olgehalt. An example of another chemical property is the pH. Also, the lubricant usually has a certain electrical conductivity, a certain optical refractive index and a certain transparency. These and other physical and chemical properties of the lubricant change seriously during operation.

To detect such properties, the mechanical device has a sensor device 5. The sensor device 5 has at least one lubricant sensor 6, which - see FIG. 2 in addition - is arranged in the vicinity of one of the bearings 3. As a rule, at least one such lubricant sensor 6 is arranged in the vicinity of each bearing 3. The lubricant sensor 6 is in the basic body 1, in the example of FIG 1 so inside the electric machine arranged. He is in contact with the lubricant.

The lubricant sensor 6 is designed in such a way that at least one first electrical quantity El which is characteristic of a lubricant quantity-independent property of the lubricant can be determined by it. If necessary, From the lubricant sensor 6, it is also possible to determine other electrical quantities E 2,... En which are characteristic of further lubricating agent-independent properties of the lubricant.

In the simplest case, the sensor device 5 outputs only signals e1,..., Which correspond directly and directly with electrical quantities E1,... E determined by the lubricant sensor 6. In this case, the sensor device 5 does not carry out any further processing of the electrical quantities El,... E determined by the lubricant sensor 6. In this case, further Sinai evaluation can alternatively be omitted, can be performed intellectually by a human or automatically by an evaluation device 8 take place, the signals el, ... en are supplied.

As a rule, however, the sensor device 5 has its own evaluation device 9 assigned to the sensor device 5. The evaluation device 9 assigned to the sensor device 5 is arranged on or in the basic body 1. It is connected to the existing lubricant sensors 6. As a function of the electrical quantities El,... En supplied by the lubricating means sensors 6, it determines at least one information I about the mechanical engagement as such and outputs a signal e corresponding thereto. For example, it can issue an alarm or warning message when a bearing-damaging condition is detected or imminent. Also, (alternatively or additionally) an indication of the next impending lubricant change may be given, for example a message stating that a lubricant change should be made within the next 100, 50 or 20 hours of operation. The signal e corresponding to the information I can be output as an alternative or in addition to the signals e1,... The determination of the electrical quantities El,... En through the lubricant sensor 6 is possible in various ways. In particular, the lubricant sensor 6 can determine the electrical quantities El,... En by a chemical and / or physical analysis of the lubricant. For example, the lubricant sensor 6 can be obtained by chemical analysis of the Schmiermit ^¬ means of the pH value, the content of metal particles, in the case of a grease determine its water content and the degree of oxidation of the oil content. By physical analysis of the lubricant, the lubricant sensor 6 can determine, for example, the conductivity of the lubricant, its breakdown voltage, its optical transparency, its optical haze, its refractive index, its density and so on. Which variables are determined in the individual case on the basis of which analyzes is at the discretion of the person skilled in the art.

The lubricant sensor 6 transmits the electrical quantities El, ... En determined by it to the evaluation device 9, as shown in FIG. 3, which outputs, for example, a corresponding signal e1,... E for each electrical quantity El,.. , The evaluation device 9 can be derived using the transmitted to them electrical Big El, ... En more information I and output an ent ^¬ speaking signal e. In the further information I may possibly (per information) more of the electrical Great El, ... En received. For example, the output further information I can with the rest period kor ^¬ respondieren until the next maintenance of the mechanical device must be done. In this case, for example, on the basis of each individual electric Great El, ... En a

Remaining time to be determined and output as further information I, the average or the minimum of the remaining time.

As already mentioned, the mechanical device can have a plurality of bearings 3. Usually 3, each bearing the moving ^¬ che sensors, so for example one or more lubricants sensors. 6 For the further embodiment of the sensor device 5 exists a variety of ways, which will be explained in more detail below in connection with FIG 4.

For example, it is possible that the sensor device 5 does not have its own power supply. In this case, the sensor device 5 has a power supply interface 10. Via the power supply interface 10, the sensor device 5 can be supplied with electrical energy from outside the mechanical device.

In the simplest case, the power supply interface 10 is formed as a pre-assembled connector. However, contactless embodiments are also possible, for example by means of a capacitive or inductive coupling. Excitation, for example, by radio waves (similar to transponders) is conceivable.

Furthermore, it is possible for the sensor device 5 to have a human-machine interface 11. Via the human-machine interface 11, the signals el, ... e, e output by the sensor device 5 can be output to the human 7.

It is possible that the signals .alpha.,... E and e output by the sensor device 5 are automatically output by the sensor device 5 permanently or cyclically one after the other via the human-machine interface 11. Alternatively, it is possible that the sensor device 5 from the menu 7 via the man-machine interface 11, a retrieval command A for retrieving signals el, ... en, e is predetermined.

The human-machine interface 11 can also be connected to the sensor device 5 alternatively via lines or without contact. By contrast, the human-machine interface 11 as such-that is, the device which directly outputs information e, el,... To the human being 7 or retrieves it. lack A from the person 7 receives - can not kon ^¬ tactless be formed, but must of course be physically present.

Alternatively or in addition to the presence of human

Machine interface 11, it is possible that the Sensorein ^¬ direction 5 has a data interface 12, via which the signals el, ... s and / or e to a device external processing unit - for example, the already mentioned evaluation device 8 - can be output. Analogously to the energy supply interface 10, a line-connected contact can alternatively also be produced here or the data interface 12 can be designed as a contactless interface.

The transmission of data and information between the sensor device 5 and the processing unit 8 can take place analogously to the data traffic between the sensor device 5 and the human-machine interface 11. In particular, it may be possible for the processing unit 8 to prescribe a polling command A for retrieving signals el,... And e to the sensor device 5.

The sensor device 5 can be permanently programmed. Examples of play, the sensor means 5 having an internal memory 5, in which a program and Parametπerungen are stored that define the operation of the Sensoreinrich ^¬ tung. 5 For example, a program and several parameter sets can be stored in the memory 5, with at most one of the parameter sets being activated and the other parameter sets being deactivated. In this case, for example, the program could be executed and the parameters of the activated parameter set could be used as part of the execution of the program. Each parameter set contains a number of reference values. The reference values are characteristic of one of the electrical quantities El,... En or the corresponding property of the lubricant. However, it is also possible that the sensor device 5 has a programming interface 13, via which the Sensorein ^¬ direction 5 is programmable. The programming interface 13 may - as well as the data interface 12 - alternatively have contacts or be designed as a contactless interface.

The extent of programmability can be determined as needed. It can for example be possible to others the program as such, so the effect of the Sensorein ^¬ device 5 as such. Alternatively or additionally, it may be possible for new parameter sets to be written into the memory 5 '. Again alternatively or additionally, it may be possible to program which of the parameter sets is activated.

A storage of a parameter set in the memory 5 'can also be done in other ways. In particular, it is mög ^¬ lich that the sensor device 5 carries out a self-parameterization. In this case, the sensor device 5 checks whether a status signal is present. If the state signal is present, it stores in the memory 5 'values determined as Re ference ^¬ values from, which are characteristic of the corresponding electrical Great El, ... En, which were medium sensor of the lubricant collected 6 at this time. In this case, for example, the program may determine an absolute or relative tolerance range within which later measured values are considered to be correct.

As an additional signal, for example, a signal can be used, which is supplied to the sensor device 5 from the outside (for example via the man-machine interface 11 or the data interface 12). Alternatively, the sensor device 5 could also pre-check the contents of the memory 5 'and store reference values in the memory 5' if the memory 5 'is still unrecorded, for example containing all logical zeroes. In connection with FIG. 5, the mode of operation of the sensor device 5 will be briefly explained again below.

According to FIG 5, the sensor device 5 checks in a step Sl, if they should work in normal operation. If this is the case, the sensor device 5 proceeds to steps S2 to S7. Otherwise, it branches to steps S8 to SlO.

In step S2, the sensor device 5 activates the lubricant sensor 6. In step S3, the sensor device 5 receives the supplied from the lubricant sensor 6 electric large El, ... En.

In a step S4, the sensor device 5 checks whether the supply signal is present. If this is the case, the sensor device 5 moves to step S5, otherwise to step S6.

In step S5, the sensor device 5 uses the electrical parameters El, ... En to determine reference values and store them in the memory 5 '.

If an evaluation device 9 is present internally, a processing of the electrical parameters El, ... En takes place in the context of step S6. In this case, the sensor device 5 determines the derived information I as well as the signals el, ..., e. Otherwise, in the context of step S6, only a determination of the signals e1,... In a step S7, the sensor device 5 outputs the signals el,... And possibly also e determined by it.

In step S8, the sensor device 5 checks whether it is in the programming mode. If this is the case, it proceeds to step S9, otherwise to step S10.

In step S9, the sensor device 5 takes over a programming supplied to it and stores it in the memory 5 '. In step S, the sensor device 5 leads a different Re ^¬ action, which is not relevant in the context of the present invention.

The erfmdungsgemaße sensor device 5 can be extended as desired and needed. For example, it is possible to capture ^¬ satzlich to the above Big El, ... En more Great. For example, the sensor device 5 could additionally detect a lubricant-dependent property and output a signal (oil level or the like) depending thereon. Furthermore, the sensor device 5 can also be detected by means of corresponding sensors, which are not shown in the FIGURE, also other lubricant-independent properties of the mechanical device. Also in this case a dependent signal can be output. For example, a noise development of the mechanical device can be detected and evaluated via spectrum and volume. Thus, in ^¬ a grinding or a hum of the mechanical device can play, be detected. Also, temperatures, load cycles, prevailing field strengths (electrical and / or magnetic), humidity, ionization of the indoor air, etc. can be detected. A more or less complete monitoring of the mechanical device possible - this is - depending on the size of the detected white ^¬ more advanced features of the mechanical device.

By erfmdungsgemaße embodiment of the mechanical device can be determined continuously, the quality of the lubricant used. This can be optimized on the one hand required maintenance cycles. On the other hand, mechanical damage to the storage system can be avoided, since maintenance can be requested even before the mechanical damage. By analyzing the history of the measurement results Schmiermit ^¬ tel may further optionally be optimized. The inventive solution can be used in various lubricating ^¬ material classes. Examples of such classes of lubricant are oil mist lubrication, use of standard fumigant-based fats, ester oils with lithium thickener, etc.

The above description is only for explanation of the present invention. The scope of the present invention, however, should be determined solely by the appended claims.

Claims

claims

1. A mechanical device having a basic body (1) and at least one element (2) movably mounted relative to the basic body (1) in at least one bearing (3), wherein the bearing (3) is lubricated by means of a lubricant, d a d e r c h e c e n e c e,

- that on or in the base body (1) a sensor device (5) is arranged a near the bearing (3) arranged at least, are in contact with the lubricant the lubricant ^¬ sensor (6),

that at least one first electrical quantity (El), which is characteristic of a first lubricant quantity-independent property of the lubricant, can be determined by the lubricant sensor (6), and

- That of the sensor device (5) at least one of the first electrical large (El) dependent first signal

(el, e) is dispensable.

2. Device according to claim 1, characterized in that the lubricant sensor (6) determines the first electrical quantity (El) by a chemical analysis of the lubricant.

3. Device according to claim 1, characterized in that the lubricant sensor (6) determines the first electrical quantity (El) by a physical analysis of the lubricant.

4. A device according to claim 3, wherein said device comprises:

that a second electrical quantity (E2), which is characteristic for a second lubricant quantity-independent property of the lubricant, can also be determined from the lubricant sensor (6),

- That the lubricant sensor (6) determines the second electrical quantity (E2) by a chemical analysis of the lubricant and - That the first signal (e) is also dependent on the second electrical large (E2) and / or at least one of the second electrical large (E2) dependent second signal (e2) can be output from the sensor device (5).

5. Device according to one of claims 1 to 4, since ^{¬ characterized in} that the first signal (el) with the first electrical Great (El) corresponds.

6. Device according to one of claims 1 to 4, characterized in that the sensor device (5) has an associated with the at least one lubricant sensor (6) evaluation device (9), of which in dependence on the first electrical large (El) information ( I) can be determined as such via the mechanical device, and that the first signal (e) corresponds to the information (I) via the mechanical device as such.

7. Device according to one of the above claims, characterized in that the sensor device ^¬ (5) has a human-machine interface (11) on ^¬ over which the first signal (el, e) to a human (7) can be output ,

8. Device according to claim 7, characterized dadurchgekenn ^¬ records that the sensor device (5) of the human (7) via the man-machine interface (11) a retrieval command (A) for retrieving the first signal (el, e) is predetermined ,

9. Device according to one of the above claims, characterized in that the sensor device (5) has a power supply interface (10) for supplying the sensor device (5) from outside the mechanical device with electrical energy.

10. Device according to one of the above claims, characterized in that the sensor device ^¬ (5) has a data section (12) via which the first signal (el, e) can be output to a device external processing unit (8).

11. Device according to claim 10, characterized in that the sensor device (5) from the processing unit (8) via the data interface (12), a retrieval command (A) for retrieving the first signal (el, e) is predetermined.

12. Device according to one of the above claims, characterized in that the sensor device (5) has a programming interface (13) via which the sensor device (5) is programmable.

13. The device of claim 12, wherein the programming comprises writing reference values for the at least one lubricant-quantity-independent property into a memory (5 ') of the sensor device (5).

14. A device as claimed in claim 12 or 13, wherein said programming includes

Activation and / or deactivation of reference ^{values written} in a memory (5 ') of the sensor device (5) are summarized.

15. Device according to one of claims 9 to 14, d a d u r c h e c e n e e c e in that at least one of the interfaces (10,12,13) is formed as a contactless interface.

16. Device according to one of the above claims, characterized in that of the sensor device (5) in response to a state signal in a memory (5 ') of the sensor device (5) values as Reference values are stored, which are characteristic of one of the lubricant sensor (6) determined at this time first electrical quantity (El).

17. Device according to one of the above claims, characterized in that of the Sen ^¬ soreinrichtung (5) additionally at least one siermittel- volume-dependent property can be detected and a dependent thereon signal can be output.

18. Device according to one of the above claims, characterized in that at least one lubricant-independent property of the mechanical device can additionally be detected by the sensor device (5) and a signal dependent thereon can be output.