Gear and compressor device equipped with such gear

Abstract

A gear is provided with spokes (17) extending between a rim (16) supporting a gear mesh (15) and a corresponding gear hub (18), where free spaces (19) are located between the spokes (17) extending between the rim (16) and the gear hub (18), characterized in that at least one of the free spaces (19) is filled with a block (20) made of a rigid incompressible material, and the block (20) is made of a non-compressible material. Wherein a viscoelastic material (21) is positioned between the gearwheel (10) on the one hand and the block (20) on the other hand.

Description

[0001] This application is a divisional application of the invention patent application with the application date of February 4, 2021, application number 202180012928.X (international application number PCT / IB2021 / 050894), and invention name “Gear and compressor equipment equipped with such a gear”. Technical Field

[0002] The present invention relates to a gear.

[0003] In particular, the present invention relates to a gear that can be used in a gearbox or gear transmission, for example between a compressor element and a drive. Background Art

[0004] It is known that compressor elements are driven by a drive at high speed and are subject to high dynamic process forces.

[0005] As a result, the system is prone to vibration-related problems. Vibrations generated in the compressor elements and / or the drive can be transmitted through the transmission. These vibrations are primarily caused by imbalances in the drive and pulsations in the process forces of the compressor elements, combined with the occurrence of resonances.

[0006] Different dynamic problems occur in both the drive and the compressor elements.

[0007] One of the problems is the combination of torque and bending of the shaft and compression of the bearings, the combined torque-transverse "mode-shape" or torque and axial mode shapes, or using gear pairs with helical gear meshes.

[0008] Solutions are already known that use a flexible coupling between the drive and the compressor element.

[0009] The flexible coupling ensures dynamic decoupling between the torsional dynamics of the drive and the compressor element.

[0010] Furthermore, this will also simplify the alignment between the two and result in damping of vibrations.

[0011] However, this flexible connection exhibits a number of disadvantages:

[0012] - Flexible connections represent additional costs;

[0013] - Increased size of gear transmissions;

[0014] - Additional bearings must be provided, as the floating gears require separate bearings;

[0015] - the flexible coupling must transmit all the power and is therefore susceptible to wear and tear as the flexible material degrades over time, necessitating regular replacement of the flexible transmission; and

[0016] - The maximum permissible speed is limited, whereas the new motor itself allows higher speeds.

[0017] This is why so-called direct couplings are preferred in modern machine design; the floating gear is directly on the motor shaft.

[0018] This direct connection is very stiff, with the result that all mode shapes are connected.

[0019] Furthermore, the modes of such couplings are very undamped, as there is no damping material for the flexible coupling. Consequently, the drive is susceptible to dynamic excitations such as imbalances and compression pulsations.

[0020] The combined torsional-transverse mode shape (ie the combination of torque and bending of the shaft) results in the so-called rattle of the gear.

[0021] This is caused by certain mode shapes being excited or transmitted by the drive and / or compressor elements.

[0022] Gear wheels with spokes are already known, which are used in transmissions to decouple the drive from the compressor element in a dynamic manner.

[0023] By using gears with spokes, the gears become more torsionally flexible, thereby effectively preventing the transmission of vibrations, especially torsional vibrations.

[0024] A consequence of this gearing is that the eigenfrequencies of certain mode shapes are shifted so that they are not excited.

[0025] For certain mode shapes, this is not always possible, as a toothed gear with spokes cannot be made too weak. Furthermore, during startup, it is still necessary to experience a reduced mode shape.

[0026] WO 2011 / 047807 A1 describes a device for damping torsional vibrations in rotating components, using rubber elements mounted between the rotating components and transmitting torque via the rubber elements. This has the disadvantage that there is not only a greater risk of rubber failure, but also that the rubber must be regularly replaced due to wear and tear. Summary of the Invention

[0027] The object of the present invention is to improve the properties of a toothed wheel with spokes so that the damping value of the transmission can be increased, so that the excitation of certain mode shapes can be reduced or avoided, and to provide a solution to at least one of the aforementioned and other drawbacks.

[0028] To this end, the invention relates to a gear wheel provided with spokes extending between a rim supporting a gear meshing portion and a corresponding gear hub, whereby free spaces are located between the spokes extending between the rim and the gear hub, characterised in that at least one of the free spaces is filled with a block made of a rigid, incompressible material, whereby a viscoelastic material or a viscous fluid is positioned between the gear wheel on the one hand and the block on the other hand.

[0029] This offers the advantage that by filling the free space with blocks of incompressible and viscoelastic material, the gear will show good damping properties of the torque-transverse mode shapes and any other possible mode shapes of the coupling.

[0030] The vibrations and bending of the shaft will deform the gear with its spokes.

[0031] Said deformation will compress the viscoelastic material between the block and the gear, which will cause damping, while the block will ensure that the deformation of the gear remains limited.

[0032] It is important to note that by providing the block or "core" from an incompressible material, the viscoelastic material can be compressed more efficiently between the block and the gear as the gear deforms due to the vibrations that occur than if the free space were completely filled with viscoelastic material.

[0033] An alternative embodiment relates to a gear wheel provided with spokes extending between a rim supporting the gear meshing portion and a corresponding gear hub, whereby free spaces are located between the spokes extending between the rim and the gear hub, characterized in that at least one of the free spaces is completely filled with a block made of viscoelastic material.

[0034] It should be noted that in the described embodiment there is no additional viscoelastic material between the gear on the one hand and the block on the other hand.

[0035] Such an embodiment will also achieve the damping effect as described above.

[0036] Since it is the compression of the viscoelastic material that will generate the damping properties, providing a mass in the free space will improve the damping properties of the gear according to the invention.

[0037] In a practical embodiment, a viscoelastic material is installed between the spokes and the blocks. This material will be loaded in tension and thus provide damping.

[0038] Additionally or alternatively, a viscoelastic material is mounted between the block on the one hand and the gear hub and rim on the other hand. This material is loaded in shear to then provide damping again.

[0039] Depending on the application in which the gear is to be used, or depending on the expected vibrations and required damping in said application, the viscoelastic material may be installed at the desired location.

[0040] Not only can the location be selected, but also the amount of viscoelastic material that can be installed. The properties and composition of the viscoelastic can also be selected, as can the initial compression of the viscoelastic material. The latter is the compression of the viscoelastic material when the block is installed in the free space between the spokes.

[0041] In practical embodiments, the viscoelastic material takes the form of one or more gaskets or O-rings.

[0042] Such a gasket may be located between the block and the gear. An O-ring may be installed around the block.

[0043] In a practical embodiment, a block consists of different partial blocks.

[0044] In a practical embodiment, additional partial spokes may be added which are connected only to the hub or only to the rim. The blocks or partial blocks are then placed between the full spokes and the partial spokes.

[0045] Viscoelastic material may also be installed between the different partial blocks, which will provide additional damping.

[0046] In a preferred embodiment, the block is part of or integrally formed with the gear hub.

[0047] A groove will be located between the gear on the one hand and the block on the other hand, said groove being filled with fluid.

[0048] Thus, a squeeze film damper is formed which will damp torsional vibrations.

[0049] The present invention also relates to a compressor device, comprising:

[0050] - a compressor element for compressing a gas,

[0051] - a drive device for driving the compressor element;

[0052] - a transmission device between the drive device and the compressor element;

[0053] It is characterized in that the transmission comprises at least one gear wheel according to the invention.

[0054] This offers the advantage that by applying a gear wheel with improved damping properties according to the invention, the damping value of the transmission can be increased, so that the excitation of certain mode shapes can be reduced or avoided.

[0055] The gears may be mounted on both the shaft of the drive means and the shaft of the compressor element. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In order to better illustrate the characteristics of the invention, some preferred embodiments of the gear according to the invention are described below by way of example and without any limiting character, with reference to the accompanying drawings, in which:

[0057] Figure 1 A compressor device according to the invention with a gear according to the invention is schematically shown;

[0058] Figure 2 and Figure 3 Shown Figure 1 gears;

[0059] Figure 4 Shown according to Figure 3 Section along line IV-IV in ;

[0060] Figure 5 Shown according to Figure 3 The section of line VV in ;

[0061] Figure 6 Shown Figure 3 variants of;

[0062] Figure 7 Shown according to Figure 6 The section along line VII-VII in FIG.

[0063] Figure 8 Shown according to Figure 6 The section along line VIII-VIII in ;

[0064] Figure 9 Shown Figure 2 variants of;

[0065] Figure 10a and Figure 10b Shown Figure 2 Two other variants of;

[0066] Figure 11 Shown Figure 6 variants of;

[0067] Figure 12a 、 Figure 12b and Figure 12c Shown Figure 10a variants. DETAILED DESCRIPTION

[0068] Figure 1A compressor device according to the invention is schematically shown, which in this case is a screw compressor device 1 provided with a compressor element 2. The screw compressor device 1 may be provided with more than one such compressor element 2.

[0069] The compressor element 2 comprises a housing 3 in which two rotors 4, 5 are mounted with their shafts 6, 7 resting on bearings. These rotors 4, 5 are so-called screw rotors, i.e. a male screw rotor 4 and a female screw rotor 5, which have lobes 8 which can be rotated cooperatively into each other.

[0070] At one end 7 a of the shaft 7 of one of the rotors 5 , a first drive gear 9 is provided which can mesh with a second drive gear 10 , whereby the second drive gear 10 is mounted on a shaft 11 of a drive device 12 .

[0071] For example, the drive device 12 is an electric motor.

[0072] In this case, the drive gear 9 is mounted on the male rotor 5 , but it may also be mounted on the female rotor 4 .

[0073] Furthermore, the other end 7 b of the shaft 7 of the rotor 5 and the corresponding end 6 b of the shaft 6 of the other rotor 4 are each provided with a so-called synchronous gear 13 , 14 .

[0074] The gears 13 and 14 are typically provided with straight-cut gear meshing 15 on their associated rims 16. The gears 9 and 10 are provided with helical gear meshing. Obviously, all gears 9, 10, 13 and 14 may also have straight-cut gear meshing, or they may all have helical gear meshing or another combination.

[0075] like Figure 1 It is clearly shown that there is no elastic coupling between the electric motor 12 and the driven rotor 5 .

[0076] The transmission between the electric motor 12 and the driven rotor 5 is completely provided by the drive gears 9 , 10 .

[0077] One of the driving gears 10 is provided with spokes 17, such as Figure 2 and Figure 3 As shown, the spokes are mounted between a wheel rim 16 having a gear meshing 15 and a gear hub 18 of the gear 10 , whereby a free space 19 is located between the spokes 17 , which extends between the wheel rim 16 and the gear hub 18 .

[0078] In this case, the drive gear 10 mounted on the motor 12 is provided with such a spoke 17. Naturally, it is not excluded that another or several other gears 9, 13, 14 are provided with such a spoke 17.

[0079] Figure 2 and Figure 3 It is clearly shown that the drive gear 10 is provided with eight spokes 17 in this case, which extend from a hub 18 to the rim 16 .

[0080] In the example shown, the spokes 17 are beam-shaped and have a constant cross-section, but this is not essential to the invention.

[0081] According to the invention, at least one of said free spaces 19 is filled with a block 20 or core made of a rigid, incompressible material.

[0082] The block 20 is preferably made of, for example, aluminum or polyurethane, but other metals or composites are possible.

[0083] like Figure 3 As shown, half of the total eight free spaces 19 are filled with such blocks 20 , so that the division into four blocks 20 is symmetrical.

[0084] According to the present invention and as Figure 4 and Figure 5 As can be seen in the cross section of FIG, the viscoelastic material 21 is located between the gear 10 on the one hand and the block 20 on the other hand.

[0085] The viscoelastic material 21 is made of rubber in this case, but does not have to be made of rubber. This rubber can be natural rubber and synthetic rubber, but other materials can also be applied, such as chloroprene rubber.

[0086] As in Figure 4 , a viscoelastic material 21 is shown mounted between the block 20 on the one hand and the rim 16 and gear hub 18 on the other hand.

[0087] The viscoelastic material 21 will induce damping through shear in the material 21 and thus reduce vibrations in the modal shapes.

[0088] like Figure 5 As shown, viscoelastic material 21 is also installed between the spokes 17 and the block 20 .

[0089] The viscoelastic material 21 will induce damping through tensile loading in the material 21 .

[0090] It is possible that the viscoelastic material 21 is located only between the spokes 17 and the block 20 , whereby no viscoelastic material 21 is provided between the block 20 on the one hand and the rim 16 and gear hub 18 on the other hand.

[0091] It is also possible that the viscoelastic material 21 is located only between the block 20 on the one hand and the rim 16 and gear hub 18 on the other hand, whereby no viscoelastic material 21 is provided between the spokes 17 and the block 21 .

[0092] The amount of viscoelastic material 21 provided depends on the damping desired or required for the relevant application.

[0093] exist Figure 4 and Figure 5 In the example of FIG, the viscoelastic material 21 takes the form of a plurality of (in this case four) O-rings 22. However, it is also possible for there to be only one, two, three or more than four O-rings.

[0094] The O-ring is tightened around the block 20 .

[0095] To this end, the block 20 is preferably provided with a groove 23 or recess provided for this purpose.

[0096] Preferably, the viscoelastic material 21 is at least partially compressed, which means that the viscoelastic material 21 is already partially compressed even without any torsional or vibration load.

[0097] Tests have shown that this so-called preloading improves operation.

[0098] Instead of a hard block 20 with viscoelastic material 21 , it is also possible to choose to make the block 20 from a viscoelastic material.

[0099] Such an embodiment would be similar to Figure 3 The embodiment shown is comparable, with the difference that the viscoelastic material 21 will not be present.

[0100] The operation of the screw compressor apparatus 1 and the gear 10 is very simple and is as follows.

[0101] During operation, the drive means 12 will drive the second drive gear 10. Operation of the gears will also cause the first drive gear 9 to move.

[0102] Consequently, the male rotor 5 will move, whereby operation of the synchronising gears 13 , 14 causes the female rotor 4 to synchronously follow this movement, so as to enable the gas in the compressor element 2 to be compressed.

[0103] During operation, all kinds of dynamic force combinations of different mode shapes will occur, including, for example, combined torsional-lateral bending modes or torsional lateral modes.

[0104] Under the influence of the excited mode shape, the second drive gear 10 will deform slightly.

[0105] Consequently, the space 19 between the spokes 17 and the mass 20 will deform so that the viscoelastic material 21 located there will be compressed. Consequently, the associated mode shape is damped.

[0106] The extent to which the mode shape is damped depends on the relative deformation of the second drive gear 10, the damping material used and the preload.

[0107] Figures 6 to 8 Shown according to Figures 2 to 5 , whereby in this case the block 20 is divided into or consists of different partial blocks 20a, 20b.

[0108] In this case, two partial blocks 20a, 20b are provided.

[0109] In two of the free spaces 19 , the blocks 20 are divided parallel to the spokes 17 , and in the other two free spaces 19 , the blocks 20 are divided perpendicularly to the spokes 17 .

[0110] Just like in the previous embodiment, half of the free space 19 is filled. Of course, less, more or all of the free space 19 can also be filled.

[0111] Figure 7 A section through the block 20 divided perpendicularly to the spokes 17 is shown.

[0112] Figure 8 A section through the block 20 divided parallel to the spokes 17 is shown.

[0113] A viscoelastic material 21 is installed between the different partial pieces 20a, 20b.

[0114] In this case, the viscoelastic material 21 takes the form of one or more pads 24, slices, plates or sheets.

[0115] The spacers 24 may be mounted between the blocks 20 or between the block 20 and the gear 10 , whereby they are mounted around the associated block 20 or part of the block 20 a , 20 b .

[0116] As in the previous embodiment, the gasket 24 is mounted in a recess 23 provided for this purpose, but this does not necessarily have to be the case.

[0117] The liner 24 may also be constructed from different individual strips.

[0118] In this case, the viscoelastic material 21 in the form of the pad 24 is at least partially compressed.

[0119] Despite Figures 6 to 8 In the example of , there are always only two partial blocks 20a, 20b per filled free space, but the presence of several partial blocks 20a, 20b is not excluded.

[0120] By providing a plurality of partial blocks 20a, 20b, a thin plate-shaped partial block 20a, 20b is obtained with an O-ring 22 or a gasket 24 of viscoelastic material 21 between them.

[0121] Figure 9 Shown Figure 2 A variant embodiment whereby the block 20 is mounted on a disc 25 or plate.

[0122] The block 20 may also be formed integrally with the disc 25, which means that they are made from one piece of material.

[0123] This structure can also be applied to Figures 6 to 8 variants.

[0124] The use of such a disc 25 is useful during the manufacture of the gear 10 , ie when mounting or placing the block 20 in the free space 19 between the spokes 17 of the gear 10 .

[0125] If you can Figure 9 It is concluded that the disk 25 is positioned beside the gear 10. The disk 25 can also be positioned against the gear 10.

[0126] Figure 10a and Figure 10b Shown Figure 3 Two other variations of .

[0127] exist Figure 10a In this case, the block 20 is in direct contact with the gear hub 18. This means that no viscoelastic material 21 is located between the block 20 and the gear hub 18.

[0128] In this case, the blocks 20 are even part of the gear hub 18 , or in other words, they form an integral part therewith.

[0129] Between the blocks 20 on the one hand and the spokes 17 and rim 16 on the other hand, a viscoelastic material 21 is mounted.

[0130] Figure 10b The same embodiment is shown, but here the form of the block 20 is different. In this case, there are projections 26 on the rim 16 and associated recesses 27 in the block 20. The block 20 thus has a V-shaped cross section.

[0131] Figure 11 Shown Figure 6 , whereby in this case the second drive gear 10 is provided with a plurality of partial spokes 28 which are only connected to the gear hub 18. In other words, they do not extend from the gear hub 18 all the way to the rim 16 in the same way as the spokes 17.

[0132] It is not excluded that part of the spokes 28 is connected only to the rim 16 .

[0133] In this case, there are four such partial spokes 28 .

[0134] The block 20 is placed in the space between the partial spoke 28 and the spoke 17 .

[0135] The viscoelastic material 21 is mounted between the block 20 on the one hand and the rim 16 , the gear hub 18 , the spokes 17 and / or parts of the spokes 28 on the other hand.

[0136] Figure 12a 、 Figure 12b and Figure 12c A final variant of the gear wheel 10 according to the invention is shown.

[0137] Here, the groove 29 is located between the gear wheel 10 on the one hand and the block 20 on the other hand.

[0138] The width or thickness of the groove is preferably less than 1 mm.

[0139] The groove is actually produced, for example, by means of an EDM or electrical discharge machine and therefore has a projection 30 at its end.

[0140] The groove 29 is filled with a fluid.

[0141] Such a fluid has viscous properties and is, for example but not necessarily, oil.

[0142] In this way, a squeeze film damper is formed in the groove 29 .

[0143] In order to ensure that the oil in the groove 29 effectively remains in the groove 29 during rotation of the gear 10 , the gear 10 is provided in this case with two cover plates 31 (one on each side of the gear 10 ) to close the groove 29 .

[0144] Alternatively, only one cover plate 31 may be provided.

[0145] The cover plate 31 can completely cover the groove 29, which means that the fluid in the groove 29 cannot leak out. This has the advantage that once the oil or fluid is injected or inserted into the groove 29, the oil is no longer needed.

[0146] However, the cover plate 31 or the cover plates 31 may be provided with a discharge channel or a discharge opening for the fluid. Figure 12c Such an outlet channel 32 is shown schematically.

[0147] like Figure 12cAs shown, the discharge channel 32 extends vertically through the cover plate 31 from the side of the cover plate 31 facing the gear 10 near the groove 29 to the other side of the cover plate 31 (ie, the side of the cover plate 31 facing away from the gear 10 ).

[0148] It is therefore important that the outlet channel 32 is connected to the groove 29 , so that a fluid (for example oil) can flow from the groove 29 into the outlet channel 32 .

[0149] Preferably, such a drainage channel 32 will be provided for each groove 29 .

[0150] Although the outlet channel 32 is drawn as a straight channel extending in a direction perpendicular to the plane of the cover plate 31 , it is not excluded that the outlet channel 32 is oriented differently.

[0151] It is also not excluded that the different discharge channels 32 provided in the cover plate 31 converge at a certain point, whereby, starting from this point, one joint channel continues to the other side of the cover plate 31 .

[0152] From Figure 12a 、 Figure 12b and Figure 12c Such a gear is to be applied to a compressor device provided with an oil injection circuit having a nozzle 33 or the like which can inject oil into the groove 29 of the gear 10 .

[0153] The nozzle 33 will be placed at the level of the projection 30 of the groove 29. This is schematically shown in FIG.

[0154] During rotation of the gear 10 , oil will be injected into the projection 30 and the centrifugal force will force the oil into the groove 29 so that a squeeze film damper is formed in the groove 29 .

[0155] The cover plate 31 will ensure that the oil remains in the groove 29, whereby the oil can flow out via the drain channel 32. The oil that flows out can then be quickly refilled by injecting new oil using the nozzle 33.

[0156] The heat inevitably generated during operation of the compressor device 1 will ensure that the viscoelasticity of the oil decreases, so that the damping will be reduced.

[0157] By injecting new oil and draining the oil via the drain channel 32 , it is ensured that new, cold oil will always be in the groove 29 , so that the damping is always optimal.

[0158] Furthermore, the flow rate of the injected oil can be checked so that oil is injected only when vibrations and / or resonances occur.

[0159] This has the advantage that oil is only injected into the gear 10 when damping is required, so that oil is not injected unnecessarily.

[0160] The speed of the compressor device 1 at which such vibration or resonance occurs can be predefined and the flow rate of oil injection can be adjusted to inject oil when the compressor device 1 runs at said speed, but it is also possible to perform real-time measurements of the vibration or resonance during operation of the compressor device 1 and adjust the oil injection based on such measurements.

[0161] Although the gear according to the present invention is used in the transmission of a screw compressor in the example shown, this does not exclude the use of the gear in other machines. The present invention is not limited to the use of the gear according to the present invention as a second drive gear, but another gear or combination of gears of a compressor device can also be implemented in this way.

[0162] The invention is in no way limited to the embodiments described as examples and shown in the drawings, but the gear wheel according to the invention can be realized in all kinds of forms and sizes without departing from the scope of the invention.

Claims

1. A gear wheel provided with spokes (17) extending between a rim (16) supporting a gear meshing portion (15) and a corresponding gear hub (18), wherein a free space (19) is located between the spokes (17) extending between the rim (16) and the gear hub (18), characterized in that At least one of the free spaces (19) is filled with a block (20) made of a rigid, incompressible material, whereby a viscoelastic material (21) or a viscous fluid is positioned between the gear (10) on the one hand and the block (20) on the other hand.

2. The gear according to claim 1, characterized in that The block (20) is made of aluminum or polyurethane.

3. The gear according to claim 1 or 2, characterized in that: The viscoelastic material (21) is made of rubber or another damping material.

4. A gear according to any one of the preceding claims, characterized in that The viscoelastic material (21) takes the form of one or more gaskets (24) or O-rings (22).

5. The gear according to claim 4, characterized in that The gasket (24) or O-ring (22) is mounted around the block (20) in a groove (23) or recess provided for this purpose.

6. A gear according to any one of the preceding claims, characterized in that The viscoelastic material (21) is mounted between the spokes (17) and the block (20).

7. A gear according to any one of the preceding claims, characterised in that The viscoelastic material (21) is mounted between the block (20) on the one hand and the gear hub (18) and the rim (16) on the other hand.

8. A gear according to any one of the preceding claims, characterized in that The block (20) is composed of different partial blocks (20a, 20b).

9. The gear according to claim 8, characterized in that A viscoelastic material (21) is mounted between the different partial blocks (20a, 20b).

10. A gear according to any one of the preceding claims, characterised in that The gear (10) is provided with an additional partial spoke (28) connected only to the gear hub (18) or the wheel rim (16), wherein the block (20) is mounted between the spoke (17) and the partial spoke (28).

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