Data processing: measuring – calibrating – or testing – Measurement system in a specific environment – Electrical signal parameter measurement system
Reexamination Certificate
2002-05-31
2004-03-16
Bui, Bryan (Department: 2863)
Data processing: measuring, calibrating, or testing
Measurement system in a specific environment
Electrical signal parameter measurement system
C702S075000, C702S076000, C702S183000, C702S189000
Reexamination Certificate
active
06708128
ABSTRACT:
This application is based on and claims priority under 35 U.S.C. §119 with respect to Swedish Patent Application No. 0101984-3 filed on May 31, 2001, the entire content of which is incorporated herein by reference.
FIELD OF THE INVENTION
The present invention relates to a device, computer program product and method for indicating a function deviation of one or more details of manufacturing equipment using frequency component analysis for analyzing deviations from a nominal product shape and an actual product shape using surface data of a physical surface describing the present product shape, the product having been processed by the manufacturing equipment. It also relates to a device for indicating the quality of a product processed by the manufacturing equipment.
The invention also relates to a method of configuring a frequency map comprising a set of function deviation indicating frequencies, the map being intended to be used in a device for indicating a function deviation of one or more details of a manufacturing equipment.
BACKGROUND OF THE INVENTION
One way of obtaining indications of whether there are problems in manufacturing equipment is to use a vibration sensor to sense vibrations of the manufacturing equipment. A frequently used method of analyzing the vibrations is based on the Fourier analysis.
In U.S. Pat. No. 4,453,407 to Sato et al., assigned on its face to Hitachi, a vibration diagnosis method and apparatus for rotary machines are presented. It is adapted for measuring the vibration of a rotor shaft of a rotary machine, extracting the vibration component synchronous with the revolution of the rotor shaft from the measured vibration data, comparing the amplitude of the extracted vibration component with the amplitude of the overall vibration, analyzing the causes of the synchronous vibration component when the result of the comparison meets a predetermined reference, judging, in accordance with the result of the analysis, whether the vibration due to mass unbalance is attributable to an abrupt generation of mass unbalance or to a thermal bow of the rotor shaft, and displaying the result of the judgment.
In U.S. Pat. No. 4,425,798 to Nagai et al., assigned on its face to Kawasaki Steel, an apparatus for diagnosing abnormalities in rotating machines is presented. It is intended to be used for the diagnosis of rotary machinery equipment and utilizes a fast Fourier transform frequency spectrum analysis system. The presence or absence of an abnormality or trouble in the rotating machinery is determined by selecting high amplitudes out from the frequency spectrum computed by the FFT frequency spectrum analysis system, arithmetically processing distribution data of spectrum amplitudes adjacent each frequency giving the corresponding high amplitude, and detecting the amplitude, at which the frequency of vibrations of the rotating machinery has attained a maximum value, together with such a frequency.
In the fields of diagnosing and monitoring machinery equipment, Fourier analysis has been used as disclosed in DE 40 17 448 A1 and DE 40 32 299 A1.
Approaches of the kinds presented above are intended to be used to diagnose machinery equipment so that they do not malfunction and start to machine products of too low quality. A common feature of the inventions disclosed in the documents above is that the diagnosis is based on vibrations detected by sensors.
It has been realized that there are a lot of vibrations in machinery equipment to be detected by these sensors and that not all of the vibrations that can be detected in a machinery equipment lead to products of too low quality. This means that there are vibrations in machinery equipment that do not jeopardize the quality of the product. Since not all vibrations impede the quality of the product there is a risk that the presence of harmless vibrations makes it difficult to detect harmful vibrations.
Thus, it has been realized that measuring vibrations using vibration sensors on machinery equipment can lead to the disadvantage of having to deal with vibrations that do not effect the quality of the product being machined.
SUMMARY OF THE INVENTION
According to one aspect of the present invention, there is provided a device for indicating a function deviation of one or more details of manufacturing equipment using frequency component analysis. An example of a detail is a pulley, which is arranged in manufacturing equipment. Other examples of details will be presented below. The frequency component analysis can be used to analyze deviations between a nominal product shape and an actual product shape of a product using surface data of a physical surface describing the actual product shape, the product having been processed by the manufacturing equipment. The nominal product shape is the shape of a product if it had been manufactured in a perfect machine with no limitations when it comes to precision. It can also be seen as the ‘theoretical’ shape. The actual product shape (or present product shape) is the shape the product actually has. This shape is likely to vary between products intended to have the same nominal shape. It can be seen as the ‘practical’ shape.
The analysis can be based on the surface data and a set of function deviation indicating frequencies corresponding to frequencies at which function deviations occur in the one or more details. The function deviation frequencies can be comprised in a frequency map.
The device comprises an input connection, a memory comprising the frequency map, an indicator, and a computational means for receiving the surface data via the input connection, performing a Fourier transformation of the surface data, and indicating, using the indicator, the correspondence between the frequency components of the surface data and the function deviation indicating frequencies of the frequency map. These steps are responsive for performing the actual indication of a function deviation.
Analyzing how the actual product shape of a product having been processed by the manufacturing equipment varies in relation to the nominal product shape can be used as an indication of the state of the manufacturing equipment.
Surface data of a physical surface of the actual product shape describes the present (actual) product shape as it as been processed by the manufacturing equipment.
The surface data can originate from an actual surface of a rotational surface or a plane surface, for example.
Analyzing the product processed by the manufacturing equipment is advantageous since only the frequencies that affect the actual product shape is detected. This means that vibrations not resulting in a change of the actual product shape do not impede the indication. Also, it is not necessary to test every product to see whether there are problems in the manufacturing equipment. It is sufficient to test only a fraction of the products processed by a the equipment. This means that the present invention does not have to be used on a continuous basis. Another advantage is that a product can be analyzed after it has been manufactured. With other solutions this is not possible since the vibration data is normally not present at later times. This is because the Fourier analyses of other approaches are based on time directly, but in the present invention the Fourier analysis is based on a mark or a deviation of the actual product shape. Thus there is a spatial aspect of the Fourier analysis as suggested in the present invention.
Exemplary details of manufacturing equipment are details operating with frequencies, including overtones for rotating equipment within the manufacturing equipment, such as a rotary shaft, drive motor and belts. For instance, if a belt has become worn, the present invention will indicate that a function deviation has occurred, provided that there is an effect on the products manufactured by the manufacturing equipment. One feature of relevance here is relationships of revolutions of one detail and effects of these revolutions on other details within the manufacturing equipment.
The analysis can be based on
Bankeström Olle
Gabrielsson Göran
Göthberg Anders
Aktiebolaget SKF
Bui Bryan
Burns Doane , Swecker, Mathis LLP
LandOfFree
Device, computer program product and method for indicating a... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Device, computer program product and method for indicating a..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Device, computer program product and method for indicating a... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3258819