Patent Application
20240068474
The present invention relates to a pair of intermeshing preferably oil-free running gears in particular for dual- or multi-shaft vacuum pumps. Further, the present invention relates to a vacuum pump system comprising a pair of intermeshing preferably oil-free running gears and an apparatus, comprising such a vacuum pump system and further comprising a gear wear detection device. Further, the present invention relates to a method for gear wear detection in intermeshing running gears preferably of a dual- or multi-shaft vacuum pumps.
Known gear wear detection in intermeshing oil-free running gears involves the inspection of gear components and the measurement of gear wear parameters, which usually requires an interruption of operation and partial disassembly of the machine comprising the running gears.
One disadvantage of known solutions for gear wear detection are high costs caused by the interruption of operation and the inspection of the machine comprising the running gears. Other disadvantages include complex disassembly and reassembly of machine parts and even potential failure of the machine comprising intermeshing oil-free running gears if gear wear is not detected in time.
The discussion above is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter. The claimed subject matter is not limited to implementations that solve any or all disadvantages noted in the background.
An object of the present invention is to provide an efficient and reliable solution for gear wear detection in intermeshing running gears, thereby overcoming the disadvantages of the prior art.
The object is achieved by the pair of intermeshing preferably oil-free running gears in particular for dual- or multi-shaft vacuum pumps according to claim 1; the vacuum pump system, comprising a dual- or multi-shaft vacuum pump and a pair of intermeshing preferably oil-free running gears according to claim 7; the apparatus, comprising a vacuum pump system and further comprising a gear wear detection device according to claim 10; and the method for gear wear detection in intermeshing preferably oil-free running gears according to claim 14.
The pair of intermeshing running gears preferably for dual- or multi-shaft vacuum pumps according to the invention comprises a first running gear and a second running gear meshing with each other, wherein at least the first running gear comprises a first gearwheel and a second gearwheel. The first and the second gearwheel of the first running gear are axially arranged. In this way the two gearwheels of the first running gear build a single running gear configured to mesh with the second running gear. Therein, preferably, the intermeshing running gears are operated oil-free.
According to the invention, the first gearwheel comprises a predetermined number of first cogs of the same dimension and the second gearwheel comprises a at least one second cog, wherein the second cog has a dimension smaller to a predetermined amount than the dimension of the first cogs. The first and the second cogs provide contact surfaces for the second running gear as the first and the second running gears are designed in an intermeshing manner. Preferably, the differences in dimension of the first and second cogs to a predetermined amount w concern those parts of the first and the second cogs that are in direct contact, when the first and the second running gears are meshing.
Further, according to the invention the first gearwheel is made of a material with an elastic modulus different than the elastic modulus of the material of the second gearwheel. As the first gearwheel is made of a material with an elastic modulus different than the elastic modulus of the material of the second gearwheel, the acoustic properties of the first and the second gearwheel, respectively will be different. In particular, the acoustic frequency spectrum of the sound produced by the second running gear being in contact with the first gearwheel will be distinct from the acoustic frequency spectrum of the sound produced by the second running gear being in contact with the second gearwheel. This may have the advantage that via the detected differences in the acoustic frequency spectra gear wear can be detected.
Preferably, the predetermined amount to which the dimension of the second cogs are smaller than the dimension to the first cogs corresponds to the maximum permissible wear. This may have the advantage that only upon the maximum allowable wear is reached, the second cogs come into contact with the cogs of the second running gear and before the maximum admissible wear is reached, only the first cogs of the first gearwheel will be in contact with the cogs of the second running gear. For both situations a characteristic sound is generated suitable to determine wear of the gear.
Preferably, the first gearwheel and the second gearwheel are arranged axially separated on the same shaft or in direct contact with each other. Preferably, the first gearwheel and the second gearwheel are designed in sandwich-construction, such that the second gearwheel adheres permanently to the first gearwheel.
Preferably, the material with the first elastic modulus is one of polymer and the material with the second elastic modulus is one of metal. This may have the advantage that these materials have different elastic modulus and thus, have distinct acoustic properties. This may have the further advantage that the gearwheel made from polymer can run without lubrication in combination with a mating gearwheel made from metal.
Preferably, the second running gear is made of a material with the same elastic modulus E′ as the material of the second gearwheel of the first running gear. This may have the advantage that only two different materials have to be used in order to produce the two different frequency spectra depending on the second running gear being in contact with the first gearwheel or the second gearwheel, respectively. Further, wear mainly exists at the first gearwheel. Further, this may have the advantage that low wear rates can be achieved, when the first gearwheel comes into direct contact with the second running gear.
Preferably, the predetermined number of second cogs is greater than one and less or equal than the predetermined number of first cogs. This may have the advantage that the differentiation between the frequencies of sounds produced before and upon reach of the maximum permissible wear can be improved. By selecting the number of second cogs, the indication frequency can be shifted to lower frequencies away from eigenfrequencies of the apparatus, i.e. the vacuum pump.
According to the invention a vacuum pump system, comprising a dual- or multi-shaft vacuum pump and the pair of intermeshing preferably oil-free running gears as described above is provided. The dual- or multi-shaft vacuum pump comprises a motor, a first shaft and at least one second shaft, wherein the first shaft and the second shaft are synchronously driven by the motor. The first shaft has a pumping element and the second shaft has a pumping element, which cooperates with the pumping element of the first shaft in order to convey a gaseous medium from an inlet to an outlet.
According to the invention the first shaft comprises the first running gear and the second shaft comprises the second running gear. Due to the different acoustic frequency spectra produced by the first and the second running gear before and upon reaching of the maximum permissible wear, respectively gear wear can be detected in due time, without interruption of operation or any disassembly. Thus, severe damage of the pump or on parts of the pump caused by gear wear can be prevented.
Preferably, the first shaft and the at least one second shaft are driven via a common drive belt. Therein the first and the second running gear may act as emergency running gears for the vacuum pump.
Preferably, only one of the first shaft and the second shaft is driven by the motor via a drive belt, wherein the first shaft and the second shaft are synchronized by the first running gear and the second running gear. This may have the advantage that the first and the second running gear may act as running gears for the vacuum pump synchronizing the first and the second shafts. Due to the different acoustic frequency spectra produced by the first and the second running gear before and upon reaching of the maximum permissible wear, respectively gear wear can be detected in due time, without interruption of operation or any disassembly. Thus, severe damage of the pump or on parts of the pump caused by gear wear can be prevented. Preferably, the drive belt driving the one of the first shaft or the second shaft is a V-belt.
Preferably, the system comprises two modes of operation. In the first mode of operation the second running gear is in direct contact only with the first gearwheel. In the second mode of operation the second running gear is in direct contact with the second gearwheel, when the dimension of the first gearwheel is reduced by the predetermined amount due to material wear. Further, the first frequency spectrum of the sound produced by the first running gear and the second running gear during the first mode of operation is different from the second frequency spectrum of the sound produced by the first running gear and the second running gear during the second mode of operation. This may have the advantage that in the first mode of operation the vacuum pump can still continue to operate without the risk of severe damage at the vacuum pump. When the second frequency spectrum is detected, necessary maintenance measures can be taken to ensure the protection of the vacuum pump and its components.
Preferably, during normal operation the running gears are not in contact with each other. In this case the running gears act as emergency running gears that only contact each other in an emergency mode of operation. This may have the following advantage: In the vacuum pump system according to the invention, the first shaft, comprises the first running gear and the second shaft comprises the second running gear. The first and the second shaft are synchronously driven or rotated, respectively, preferably by the motor via a common drive belt. Here, the drive belt particularly is a toothed belt. If the drive belt fails to maintain synchronisation of rotation of the two shafts, the provided emergency running gears thus carry out the required synchronization of the shafts in order to prevent that the pumping elements contact each other and are thus damaged. A failure of the drive belt may occur, for example, through tearing or, if the drive belt is designed as a toothed belt, through loss or wear of teeth or elongation of the drive belt, for example due to wear. Since drive belts are inherently subjected to a certain wear in the course of their lifetime, a secure operation of a dual- or multi-shaft vacuum pump, in which the synchronization of the shafts is performed by means of a drive belt, is possible by providing emergency running gears which ensure the required synchronization if the drive belt fails.
According to the invention, an apparatus is provided comprising a vacuum pump system as described above and further comprising a gear wear detection device. The gear wear detection device according to the invention comprises a detection module that is configured to detect the sound produced by the running gears and further comprises an analysis module that is configured to analyse the frequency spectrum of the detected sound. The gear wear detection device further comprises a determination module that is configured to determine wear of the running gears dependent on a change of the analysed frequency spectrum. This may have the advantage that a gear wear can easily, reliably and automatically be detected via a gear wear detection device that is configured to detect and analyse acoustic frequency spectra without the need of interruption of operation or disassembly of the vacuum pump system.
Preferably, the determination module of the apparatus is configured to determine a deviation in the detected frequency spectrum produced by the running gears in the second mode of operation. This may have the advantage that the gear detection device can distinguish between a first mode of emergency operation and a second mode of emergency operation and thus, gear wear can be determined in due time based on the change of the analysed frequency spectrum and necessary maintenance measures can be taken to ensure further operation of the vacuum pump system.
Preferably, the gear wear detection device further comprises a displaying module that is configured to display a gear wear notification to the user if the analysed frequency spectrum is equal to the second frequency spectrum produced by the running gears in the second mode of operation. This might have the advantage that a user operating the gear wear detection device will receive a relevant information if gear wear is detected by the gear wear detection device, without the need of manual analysis and/or continuous observation of the detected signal by the user. Thus, due to the displayed information that gear wear has been detected, the user does not have to be skilled in the analysis frequency spectra and/or the determination of a frequency change that indicated a gear wear.
Preferably, the gear wear detection device is a mobile terminal. This might have the advantage that a user operating the gear wear detection is not bound to a specific location or site. A mobile terminal that is configured as a gear wear detection device can be used on different vacuum pump systems on different operational sites. Further, mobile terminals are compact and easy to use.
According to the invention, a method for gear wear detection in intermeshing preferably oil-free running gears is provided. The method comprises detecting the sound produced by the running gears and analyzing the frequency spectrum of the detected sound. The method further comprises determining a wear of the running gears dependent on a change of the analyzed frequency spectrum. This may have the advantage that gear wear can be detected be easily and reliably without the need of interruption of operation or disassembly of the vacuum pump system. Thus, costs can be reduced and continuous operation can be ensured.
Preferably, the step of determining comprises determining if the analyzed frequency spectrum is equal to the frequency spectrum produced by the running gears in the second mode of operation. This may have the advantage it can be distinguished between a first mode of emergency operation where safe operation can still be ensured and a second mode of emergency operation where severe damage to the vacuum pump system is to be expected. Thus, gear wear can be determined in due time based on the change of the analyzed frequency spectrum and necessary maintenance measures can be taken to ensure further faultless operation of the vacuum pump system.
Preferably, the method further comprises displaying a gear wear notification to the user if the frequency spectrum is equal to the frequency spectrum produced by the running gears in the second mode of operation. This might have the advantage that a user will receive a corresponding information if gear wear is detected, without the need of manual analysis and/or continuous observation of the detected signal. Thus, due to the displayed gear wear notification the user can take appropriate measures to resolve the problem. Here, the user does not have to be skilled in the analysis frequency spectra and/or the determination of a frequency change that indicated a gear wear. Thus, the complexity of gear wear detection is reduced and the efficiency of the gear wear detection process can be improved.
Preferably, the method is carried out with an apparatus as described above. Features of the apparatus can be used to further provide specific details of the method.
The Summary is provided to introduce a selection of concepts in a simplified form that are further described in the Detail Description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.
In the following, the invention is described in more detail by means of preferred embodiments with reference to the accompanying drawings, in which
The pair of intermeshing running gears preferably for dual- or multi-shaft vacuum pumps as illustrated in
As shown in
Further, the first running gear 10 comprises a predetermined number of cogs n10 and the second running gear 20 comprises a predetermined number of cogs n20. Therein, the first running gear 10 comprises a predetermined number of first cogs n11 of the first gearwheel 11 and a predetermined number of second cogs n12 of the second gearwheel 12. Therein, the predetermined number of second cogs n12 of the second gearwheel 12 is at least one.
In the example of
Further, the first cogs n11 of the first gearwheel 11 are of same dimension. In other words, all of the first cogs n11 of the first gearwheel 11 have the same size and shape. As shown in detail in
In the examples shown in
In the examples shown in
Materials with different elastic modulus show differences in their acoustic properties. Further, the frequency spectrum of the acoustic sounds produced by objects made of materials with different elastic modulus contacting each other is different than the frequency spectrum of the acoustic sounds produced by objects made of materials with same elastic modulus contacting each other.
In a first mode of operation m1, the second running gear 20 is in direct contact only with the first gearwheel 11 until the dimension of the first gearwheel 11 is reduced by the predetermined amount w due to material wear. In this first mode of operation m1, due to the contact of the first gearwheel 11 having an elastic modulus E and the second running gear 20 having a different elastic modulus E′ a first acoustic frequency spectrum f1 is produced.
In a second mode of operation m2, when the dimension of the first gearwheel 11 is reduced by the amount w due to material wear, the second running gear 20 gets in direct contact with the second gearwheel 12. In this second mode of operation m2, due to the contact of the first gearwheel 12 having an elastic modulus E′ and the second running gear 20 having the same elastic modulus E′ a second acoustic frequency spectrum f2 is produced, which is distinct from the first frequency spectrum f1.
Hence, in the above example if the second running gear 20 and the first running gear come into contact with each other, the second running gear 20 will first be in contact only with the first gearwheel 11 of the first running gear 10. When, due to material wear, the dimension of the first gearwheel is reduced, the second running gear 20 will get into contact with the second gearwheel 12 of the first running gear 10. Here, a change in the frequency spectrum of the sound detected will occur, that can be detected and analyzed consecutively. Depending on the differences of the frequency spectra produced by the second running gear 20 being in contact with the first and the second gearwheel 11, 12, respectively, an indication for gear wear is provided.
Thus, through detection of the changes in the acoustic frequency spectrum produced by the running gears 10, 20 in the different modes of operation m1, m2, gear wear can be determined without the need for interruption of the operation or disassembly of the machine comprising the running gears 10, 20.
In another preferred embodiment, the predetermined number of second cogs n12 of the second gearwheel 12 is smaller than the predetermined number of first cogs n11 of the first gearwheel 11. Here, an even better differentiation of the two frequency spectra f1, f2 during the different modes of operation m1, m2 can be achieved.
The dual- or multi-shaft vacuum pump 30 shown in
According to the invention, the first shaft 32 comprises the first running gear 10 and the second shaft 33 comprises the second running gear 20.
Therein, during normal operation the first running gear 10 of the first shaft 32 and the second running gear 20 of the second shaft 33 are not in contact with each other. In other words, the running gears 10, 20 are designed as emergency running gears, which in case an elongation of the drive belt 34, for example through wear, a loss of teeth or a tearing of the drive belt 34 occurs, ensure that the pumping elements 321, 331 do not come into contact with each other. and thus, prevent a severe damage to the pumping elements 321, 331.
Further, in the example shown in
In a second mode of operation m2, corresponding to the second emergency operation, the second running gear 20 is in direct contact with the second gearwheel 12, when the dimension of the first gearwheel 11 is reduced by the predetermined amount w due to material wear. Wear reduces the shape of the first cogs n11 to or at least close to the shape of the second cogs. Therein, by the dimension of the second cogs n12, contactless operation of the pumping elements 321, 331 is ensured.
The first frequency spectrum f1 of the sound produced by the first running gear 10 and the second running gear 20 during the first mode of operation m1 is different from a second frequency spectrum f2 of the sound produced by the first running gear 10 and the second running gear 20 during the second mode of operation m2 which difference can be detected and used in order to determine wear of the running gears 10, 20.
Thus, in the vacuum pump system illustrated in
The gear wear detection device 40 further comprises an analysis module 42 that is configured to analyze the frequency spectrum of the detected sound, and comprises a determination module 43 configured to determine a wear of the running gears 10, 20 dependent on a change of the analyzed frequency spectrum.
Therein, a user can either actively start the detection device or in planned intervals to check if gear wear has occurred, or alternatively operate the gear wear detection device continuously.
Thus, via the illustrated gear wear detection device 40, the sound produced by the running gears 10, 20 can be detected and determined if gear wear has occurred.
The determination module 43 in the example illustrated in
In the example, the gear wear detection device 40 further comprises a displaying module 44 configured to display a gear wear notification to the user if the analyzed frequency spectrum is equal to the second frequency spectrum f2 produced by the running gears 10, 20 in the second mode of operation m2.
In the illustrated example, the mobile terminal 50 further comprises a displaying module 54 configured to display a gear wear notification to the user if the analyzed frequency spectrum is equal to the second frequency spectrum f2 produced by the running gears 10, 20 in the second mode of operation m2. In an example, the gear wear notification can be in form of a written and/or spoken text-based notification, a diagram showing the detected and analyzed frequency spectrum of the sound produced by the running gears 10, 20, and/or a sound or color-based information indicating a detected gear of the running gears 10, 20. In an example, the displaying module 54 corresponds to the built-in display of the mobile terminal 50. In another example, the displaying module 54 corresponds to any other external displaying device configured to being accessed by the mobile terminal 50 to display a gear wear notification to the user.
According to an example, the mobile terminal 50 is configured to be operated by a user to start the detection of the sound produced by the running gears 10, 20, the analysis of the frequency spectrum of the detected sound, the determination of a wear of the running gears 10, 20 dependent on a change of the analyzed frequency spectrum and the displaying of a gear wear notification to the user if the analyzed frequency spectrum is equal to the second frequency spectrum f2 produced by the running gears 10, 20 in the second mode of operation m2 or at least a deviation occurs from the frequency spectrum of the first mode of operation m1.
According to another example, the mobile terminal is configured to autonomously start the detection of the sound produced by the running gears 10, 20, the analysis of the frequency spectrum of the detected sound, the determination of a wear of the running gears 10, 20 dependent on a change of the analyzed frequency spectrum and the displaying of a gear wear notification to the user if the analyzed frequency spectrum is equal to the second frequency spectrum f2 produced by the running gears 10, 20 in the second mode of operation m2. Here, the autonomous operation of the mobile terminal 50 can be a continuous operation or an operation within any predetermined intervals.
The first step of the method comprises detecting S1 the sound produced by the running gears 10, 20. In the second step the method comprises analyzing S2 the frequency spectrum of the detected sound and in a third step the method comprises determining S3 wear of the running gears 10, 20 dependent on a change of the analyzed frequency spectrum.
Preferably, the step of determining S3 comprises determining if the analyzed frequency spectrum is equal to the frequency spectrum f2 produced by the running gears 10, 20 in the second mode of operation m2.
In a preferred embodiment, the method further comprises the step of displaying S4 a gear wear notification to the user if the frequency spectrum is equal to the frequency spectrum f2 produced by the running gears 10, 20 in the second mode of operation m2.
Thus, a pair of intermeshing preferably oil-free running gears in particular for dual- or multi-shaft vacuum pumps, a vacuum pump system comprising a dual- or multi-shaft vacuum pump and said pair of intermeshing running gears, an apparatus comprising said vacuum pump system and further comprising a gear wear detection device and a method for gear wear detection in said pair of intermeshing running gears is provided to easily, efficiently and reliably detect a gear wear in intermeshing preferably oil-free running gears, without interruption of operation and disassembly of the machine comprising the intermeshing running gears. Hence, the costs and the complexity of gear wear detection are effectively reduced and severe damages caused by late gear wear are prevented.
Although elements have been shown or described as separate embodiments above, portions of each embodiment may be combined with all or part of other embodiments described above.
Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are described as example forms of implementing the claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2104557.0 | Mar 2021 | GB | national |
This application is a Section 371 National Stage Application of International Application No. PCT/EP2022/058187, filed Mar. 29, 2022, which is incorporated by reference in its entirety and published as WO 2022/207587 A1 on Oct. 6, 2022, the content of which is hereby incorporated by reference in its entirety and which claims priority of British Application No. GB2104557.0, filed Mar. 31, 2021.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2022/058187 | 3/29/2022 | WO |
