DE20118421U1 - Air bearing monitoring device - Google Patents

Description

G 19814 - 17 October 2001

FESTO AG & CO, 73734 Esslinqen Air bearing monitoring device

The invention relates to an air bearing monitoring device with which the functionality of air bearings in operation can be monitored.

In general, air bearings are used when particularly high demands are placed on smooth running and susceptibility to wear. Due to their design, air bearings are characterized by freedom from wear, high load-bearing capacity and particularly smooth running behavior. Possible designs of air bearings are explained, for example, in the brochure "EITZENBERGER - COMPETENCE IN AIR BEARING TECHNOLOGY" from Eitzenberger Luftlagertechnik, 82405 Wessobrunn (publication date unknown). Air bearings are suitable for supporting components that move relative to one another both in a rotary and a translational manner.

When using air bearings, pressurized air is pressed between the components that are movable relative to each other, so that an air cushion is formed that keeps the components at a distance. In order for the bearing to be able to provide the desired load-bearing capacity, a precise pressure setting is necessary. The flow setting is also subject to high accuracy requirements, since the flow is a parameter for the produced

The gap dimension created, i.e. the distance between the components to be stored, is formed. If the current flow is too low, in the worst case the gap dimension can be reduced so much that the components, which are normally kept at a distance from each other, touch each other and damage occurs.

To the applicant's knowledge, although without having any written evidence, in order to be able to monitor and, if necessary, change the above-mentioned state variables such as pressure and flow of the air used for storage, air bearing monitoring devices have already been used that have pressure and flow sensors that transmit the currently recorded data as analog voltage values via a cable connection to an external control unit that displays this actual monitoring data. The operating personnel can read the data and, from case to case, readjust a manual pressure regulator built into the compressed air flow so that the actual monitoring data set and displayed correspond to the target monitoring data required for optimal operation. The electrical energy required to operate the sensors is fed in via suitable cable connections.

It is the object of the present invention to provide an air bearing monitoring device which is easy to install and operates with high functional reliability.

This object is achieved by an air bearing monitoring device with at least one monitoring unit which is equipped with monitoring electronics for recording pressure and/or flow data of the compressed air flowing to at least one air bearing and which has at least one generator which can be driven by the flowing compressed air for generating the electrical energy required by the monitoring electronics.

This provides an air bearing monitoring device whose monitoring unit can be operated independently in terms of the required electrical energy and without a cable connection to a stationary power supply. The electrical energy required by the monitoring electronics is generated directly in the monitoring unit by the generator provided on or in it, which is driven by the compressed air supplied to supply the air bearing. Reliable operation of the air bearing monitoring device is therefore possible even with a mobile design of the monitoring unit, since electrical connection lines to a stationary energy source are not required. This also opens up the possibility of installing the monitoring unit directly on an air bearing component and designing it as a structural unit with it. This creates the prerequisite for compact dimensions and also short air paths between the recording devices provided for recording the compressed air data and the actual bearing location.

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Advantageous further developments of the invention emerge from the subclaims.

Preferably, the monitoring electronics of the monitoring unit are equipped with output means that can output the recorded pressure and/or flow data as actual monitoring data. The operating status of the air bearing(s) being monitored can be checked using the actual monitoring data output in order to be able to make or initiate changes or corrections if necessary. In a particularly simple design, the output means have optical display means provided on the monitoring unit that enable the determined actual monitoring data to be easily read. In a more convenient solution, the output means are additionally or alternatively equipped with transmission means that can be used to wirelessly transmit the actual monitoring data to a data processing device provided separately from the monitoring unit. Infrared transmission or, above all, radio transmission, the latter in particular according to the so-called Bluetooth standard, is suitable here.

In a preferred embodiment, the data processing device can have optical display means that enable visualization of the actual monitoring data received. If the data processing device is a mobile device, the operating personnel have the option of querying the data from different monitoring units one after the other during an inspection tour.

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Especially when the monitoring unit is equipped with means that allow the pressure and/or flow data of the flowing compressed air to be influenced, the operating comfort of the air bearing monitoring device can be increased by equipping the monitoring unit with input means via which the target monitoring data to be taken into account by the monitoring electronics can be entered.

The input means can, for example, be designed in the form of manual input means provided directly on the monitoring unit, for example in the form of keys, buttons or the like. However, it is particularly advisable to equip the input means with receiving means that are able to wirelessly receive target monitoring data from the transmitting means of a data processing device. Data input is then possible without any problems, without direct access to the monitoring unit being necessary. Here, too, data transmission using radio or infrared signals is particularly recommended.

It is considered optimal to provide both transmitting and receiving means on the monitoring unit and on a separate data processing device so that wireless transmission of data is possible in both directions.

To record the pressure and/or flow data of the flowing compressed air, the monitoring electronics must be equipped with suitable pressure and/or flow detection devices

It is advisable to additionally equip the system with temperature measurement devices, especially if there are several storage locations where the same operating conditions are to prevail.

Preferably, the monitoring electronics are equipped with a microcontroller that can process the data collected and, if necessary, also control the wireless signal transmission.

On board the monitoring unit there are also useful means for controlling the pressure and/or flow data of the flowing compressed air, so that a controlled setting of the desired operating state is possible in a control loop taking into account the specified target monitoring data. The control means, for example an electrically operated pressure regulator, can also obtain the required operating energy from a generator driven by the compressed air, so that self-sufficient electrical operation is guaranteed. In this respect, it is advisable to use control means with a piezoelectrically operated actuator that has only a low electrical energy requirement.

The drive unit of the generator expediently has at least one drive wheel, for example an impeller, which is set in rotation by the air flowing past. In addition, the generator preferably also contains a current transformer which converts the alternating current generated in this way into direct current.

Instead of just one compressed air-powered generator, several generators can be used, each placed at a suitable location along the air flow path.

A particularly compact arrangement is achieved if the monitoring unit is designed as a structural unit with the air bearing component that is supplied with compressed air.

If required, the monitoring electronics can be designed to record the pressure and/or flow and/or temperature data of the compressed air flowing to several air bearings. It is possible to supply all of the recording devices provided for this purpose with a generator. A common microcontroller can also be assigned to the recording devices of several air bearings.

The invention is explained in more detail below with reference to the accompanying drawing. The single figure shows an example of an air bearing monitoring device in connection with an air bearing to be monitored.

In detail, the drawing discloses, in a schematic representation, an air bearing 1 and an air bearing monitoring device 2 provided for monitoring this air bearing 1.

The air bearing 1 has two air bearing components 3a, 3b that can move relative to one another. The first air bearing component 3a is stationary in the embodiment, while the second air bearing component 3b is movable relative to the first air bearing component 3a according to double arrows 9.

is movable. In this case, the movement is a translational movement, for example a linear movement. However, a design in which the air bearing components can be rotated or pivoted relative to one another would also be conceivable.

In any case, the two air bearing components 3a, 3b have first and second bearing surfaces 4a, 4b facing each other, between which an air cushion can be generated that creates a bearing gap 5, so that the two bearing surfaces 4a, 4b are arranged at a certain distance from each other according to the gap width.

Due to the air cushion created, the two air bearing components can move relative to each other without wear and abrasion. The air bearing can therefore also be used in places where there are high requirements for air pollution control.

The compressed air required to create the air cushion in the bearing gap 5 is provided by a compressed air source P. It is connected to one of the air bearing components 3b via at least one feed channel 6, in which a plurality of outflow channels 7 are defined, which communicate with the feed channel 6. The outflow channels 7 open out to the bearing surface 4b of the relevant air bearing component 3b, whereby the creation of a large-area air cushion is ensured by suitable distribution. The outflow channels 7 could also be formed, for example, by gaps in a porous material.

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In order to optimally fulfill the current bearing task, the compressed air must be supplied to the bearing gap 5 at a certain pressure and with a certain flow rate, whereby in some cases it may be sufficient to adhere to certain pressure or flow ranges. The level of the compressed air pressure has a decisive effect on the possible load-bearing capacity with which one of the air bearing components can be loaded at right angles to its movement 9. The flow rate, i.e. the amount of air flowing through per unit of time, is a parameter for the gap size of the bearing gap 5.

With the air bearing monitoring device 2, the pressure and/or flow data of the compressed air flowing to the air bearing 1, and if necessary also other data, can be monitored in order to be able to make changes if necessary.

The air bearing monitoring device 2 has a monitoring unit 12 which is equipped with monitoring electronics 13 for recording the aforementioned data. Although in the exemplary embodiment the monitoring unit 12 serves to monitor only one air bearing, it can also be used to simultaneously monitor several air bearings, in particular one and the same machine.

The feed channel 6 used to supply the compressed air runs through the monitoring unit 12. Particularly short air paths can be maintained if the monitoring unit 12, as is the case in the embodiment,

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is designed as a structural unit with the air bearing component 3b to be supplied with compressed air. In the exemplary embodiment, this is the air bearing component that moves during operation, but it could also be a fixed air bearing component. The monitoring unit 12 is expediently attached to the air bearing component 3b mentioned at a suitable location. At least partial integration would also be possible. Long hose connections between the monitoring unit 12 and the air bearing 1 can be avoided in this way.

In the exemplary embodiment, the monitoring electronics 13 have pressure detection means 14 and flow detection means 15, which are connected to the feed channel 6 so that they can detect the air pressure prevailing in the feed channel 6 and the flow. The detected values are fed as voltage signals to a microcontroller 16 (μθ of the monitoring electronics 13). This microcontroller 16 is able to output the pressure and/or flow data detected in this way and possibly previously processed in a certain way as actual monitoring data.

The data is output by suitable output means 17 of the monitoring electronics 13. In the simplest case, optical display means 17a, indicated in dash-dotted lines in the drawing, can be provided directly on the monitoring unit 12 as output means 17, which enable the operating personnel to read the recorded actual monitoring data. The optical display means 17a can have at least one display

ge display.

A more convenient operation is possible if the output means 17, as is the case in the embodiment, are designed for wireless data transmission and have transmission means 17b provided on the monitoring unit 12, with which the actual monitoring data can be transmitted wirelessly to the reception means 18 of a data processing device 19 of the air bearing monitoring device 2, which is designed separately from the monitoring unit 12.

The data processing device 19 expediently has optical display means 22 which are able to display the received actual monitoring data so that they can be easily read by the operating personnel.

In this context, a data processing device 19 is recommended which is designed as a mobile device, in particular as a handheld device, so that it can be easily transported by a person to the location of the monitoring unit 12 in order to query data there. The data processing device can be, for example, a laptop or notebook or, preferably, a PDA.

The transmitting means 17b and receiving means 18 are designed in particular to enable radio or infrared transmission. For example, transmission according to the so-called Bluetooth standard is recommended.

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If the actual monitoring data determined indicate that there is a need for action to change the pressure and/or flow setting of the compressed air, this can be done, for example, by changing the setting of a manual pressure regulator connected in the course of the feed channel 6, which can also be installed outside the monitoring unit 12, for example in the area of the compressed air source P. However, it is preferable to have a status control integrated into the monitoring unit 12, which ensures that the actual monitoring data reliably adhere to the desired values or ranges even when the ambient conditions change.

To ensure this, the monitoring unit 12 in the exemplary embodiment is equipped with control means 23 for influencing the pressure and/or flow data of the compressed air flowing to the air bearing 1. They are preferably located on board the monitoring unit 12 and are controlled electrically. For example, these control means 23 contain an electrically controllable pressure regulator 24, in particular in the form of an electrically operated proportional valve.

The control means 23 have at least one movable, positionable actuator 25, the current position of which influences the prevailing pressure and thus also the current flow.

The electrical control variable is provided by the connected microcontroller 16 based on a comparison of the printer

actual monitoring data recorded by the flow detection means 14 and the flow detection means 15 and target monitoring data previously entered for the specific application. In this way, the monitoring unit 12 is able to keep pressure and flow constant regardless of possibly changing operating conditions.

The monitoring unit 12 is equipped with suitable input means 26 for entering the target monitoring data. In the simplest case, this can be, for example, an input keyboard or other manual input means that are arranged directly on the monitoring unit 12. In the exemplary embodiment, however, a more convenient solution is used in that the input means 26 are additionally or alternatively equipped with receiving means 26a provided on the monitoring unit 12, which are able to wirelessly receive target monitoring data transmitted by transmitting means 27 of a data processing device 19.

As with the output of the actual monitoring data, the reception of the target monitoring data is also conveniently carried out in the form of radio or infrared signals in the manner described above.

It is expedient to use a data processing device 19 in connection with the air bearing monitoring device 2, which has both receiving means 18 for the actual monitoring data and transmitting means 27 for the target monitoring data, so that two separate data

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data processing equipment must be used, which would, however, be possible in principle.

The data processing device 19 can also be a stationary device, for example a PC or a PLC, which can communicate wirelessly, in particular over larger distances, with the monitoring electronics 13 of the monitoring unit 12.

In order to be able to carry out temperature compensation if necessary, the monitoring unit 12 is expediently additionally equipped with temperature detection means 28, the data of which are also fed to the microcontroller 16 for evaluation.

The electrical energy required for the operation of the monitoring electronics 13 is advantageously generated directly on board the monitoring unit 12. This eliminates the need for electrical cables to stationary, external energy generators.

The electrical energy is generated by a generator 32 arranged on or in the monitoring unit 12, which is driven by the compressed air flowing through the feed channel 6. If required, several such generators can also be provided.

For example, the generator 32 contains a drive unit 33 placed in the air path of the flowing compressed air with one or more rotors 34 which are set in rotation by the compressed air flow.

adjustable drive wheels 34. The drive wheels can be impellers, for example. According to the known generator principle, the rotating drive wheels 34 generate an alternating voltage, which is converted into a direct voltage in a voltage converter 35 and then fed to the monitoring electronics 13.

The arrangement is expediently such that the electrical energy supplied by the generator 32 is first fed into the microcontroller 16 so that the latter receives its operating energy, wherein the detection means 14, 15, 28 connected to the microcontroller 16 are supplied with the necessary electrical energy from the microcontroller 16.

Due to the concept-related constant air consumption in the area of the air bearing 1, there is a constant air flow from the compressed air source P to the bearing gap 5, so that the drive energy required for the operation of the generator 32 is constantly available.

Nevertheless, if required, an energy storage device (not shown in detail), for example a rechargeable battery arrangement, can be provided, which enables operation of the monitoring electronics 13 and, for example, the input of target monitoring data even when the air bearing 1 is not currently being operated, for example during maintenance and setup work.

A further advantage of the described air bearing monitoring device 2 is that the control means 23 also receive their electrical energy from the compressed air-operated generator 32, in particular indirectly via the interposed microcontroller 16. Here, it is then advantageous to use control means 23 with a piezoelectrically actuated actuator 25, which requires hardly any energy.

By eliminating electrical supply lines to the monitoring unit 12, sources of errors and interference can be eliminated and problem-free operation is possible even if the monitoring unit 12 executes movements during operation due to a movement coupling with the air bearing component 3b which moves during operation.

It is possible to design the monitoring electronics 13 in such a way that it is suitable for measuring the pressure and/or flow and/or temperature of the compressed air flowing to several air bearings 1. Each air bearing can be assigned its own pressure and/or flow and/or temperature measuring means 14, 15, 28, which are expediently coupled to one and the same microcontroller 16 and which are preferably fed by a common generator 32.

Claims (20)

1. Air bearing monitoring device, with at least one monitoring unit ( 12 ) which is equipped with monitoring electronics ( 13 ) provided for detecting pressure and/or flow data of the compressed air flowing to at least one air bearing ( 1 ) and which has at least one generator ( 32 ) which can be driven by the flowing compressed air for generating the electrical energy required by the monitoring electronics ( 13 ). 2. Air bearing monitoring device according to claim 1, characterized in that the monitoring electronics ( 13 ) have output means ( 17 ) for outputting actual monitoring data. 3. Air bearing monitoring device according to claim 2, characterized in that the output means ( 17 ) contain optical display means ( 17a ), in particular at least one display provided on the monitoring unit ( 12 ). 4. Air bearing monitoring device according to claim 2 or 3, characterized in that the output means ( 17 ) have transmission means ( 17b ) for wirelessly transmitting actual monitoring data to the reception means ( 18 ) of a data processing device ( 22 ). 5. Air bearing monitoring device according to claim 4, characterized in that the transmitting means ( 17b ) are designed for radio or infrared transmission of actual monitoring data. 6. Air bearing monitoring device according to claim 4 or 5, characterized in that the data processing device ( 19 ) has optical display means ( 22 ) for visualizing the received actual monitoring data. 7. Air bearing monitoring device according to one of claims 4 to 6, characterized in that the data processing device ( 19 ) is formed by a mobile device, for example a laptop, notebook or PDA. 8. Air bearing monitoring device according to one of claims 1 to 7, characterized in that the monitoring unit ( 12 ) is equipped with means ( 23 ) for influencing the pressure and/or flow data of the flowing compressed air and has input means ( 26 ) via which target monitoring data to be taken into account by the monitoring electronics ( 13 ) can be entered. 9. Air bearing monitoring device according to claim 8, characterized in that the input means ( 26 ) have receiving means ( 26a ) for receiving wirelessly transmitted target monitoring data originating from the transmitting means ( 27 ) of a data processing device ( 19 ). 10. Air bearing monitoring device according to claim 9, characterized in that the receiving means ( 26a ) are designed to receive target monitoring data in the form of radio or infrared signals. 11. Air bearing monitoring device according to claim 9 or 10, characterized in that the data processing device ( 19 ) is formed by a mobile device, for example a laptop, notebook or PDA. 12. Air bearing monitoring device according to one of claims 1 to 11, characterized in that the monitoring electronics ( 13 ) have pressure detection and/or flow detection means ( 14 , 15 ). 13. Air bearing monitoring device according to one of claims 1 to 12, characterized in that the monitoring electronics ( 13 ) have temperature detection means (2ß). 14. Air bearing monitoring device according to one of claims 1 to 13, characterized in that the monitoring electronics ( 13 ) contains a microcontroller ( 16 ). 15. Air bearing monitoring device according to one of claims 1 to 14, characterized in that the monitoring unit ( 12 ) is equipped with control means ( 23 ) for influencing the pressure and/or flow data of the compressed air flowing to at least one air bearing ( 1 ), in particular with a pressure regulator ( 24 ), which also draws its operating energy from the generator ( 32 ). 16. Air bearing monitoring device according to claim 15, characterized in that the actuator ( 25 ) of the control means ( 23 ) is designed to be piezoelectrically actuated. 17. Air bearing monitoring device according to one of claims 1 to 16, characterized in that the at least one generator ( 32 ) has a drive unit ( 33 ) with at least one drive wheel ( 34 ) that can be set in rotation by the flowing compressed air and is preferably designed as an impeller. 18. Air bearing monitoring device according to one of claims 1 to 17, characterized in that at least one monitoring unit ( 12 ) is designed as a structural unit with an air bearing component ( 3b ) to be supplied with compressed air. 19. Air bearing monitoring device according to one of claims 1 to 18, characterized in that the monitoring electronics ( 13 ) are designed to record pressure and/or flow and/or temperature data of compressed air flowing to several air bearings. 20. Air bearing monitoring device according to claim 19, characterized in that the detection means ( 14 , 15 , 28 ) provided for detecting the pressure and/or flow and/or temperature data associated with a plurality of air bearings are supplied with energy by a common generator ( 32 ).