AU2013101117A4 - Rotor - Google Patents

Abstract

A rotor including an inner member arranged for coupling to a rotational drive and an outer member, wherein a flexible insert is interposed between the inner member and the outer member to absorb shock transmitted by the rotational drive. Ae

Description

H:\sbt\Interwoven\NRPortbl\DCC\SBT\53979411 .doc- 15/08/2013 ROTOR Field of the Invention [0001] The invention relates to a rotor, a fan assembly including a rotor, and a grain bunker system including a fan assembly having a rotor. More particularly, but not exclusively, the invention relates to a rotor in the form of a fan having a taper lock hub arranged to prevent equipment damage due to torsional vibration. Background of the invention [0002] The applicant has identified that existing rotors may be subject to damage when coupled directly to the crankshaft on an internal combustion engine. [0003] More specifically, the applicant has developed a grain bunker covering system which forms the subject matter of Australian Patent Application No. 2008202511, the entire contents of which is incorporated herein by reference. The grain bunker covering system uses a fan which creates negative pressure under a bunker cover, therefore sucking the cover to the grain, preventing the cover from flapping and tearing in windy conditions saving on grain spoilage, costly cover repairs and down labour time. In installing remote systems, the applicant has used petrol internal combustion engines to power rotation of the fan of the grain bunker cover system, as electricity may not be available or practical. The applicant has noticed that, although the fan rotor itself is proven as a robust unit from other applications, the use of the rotor in direct driven coupling with the internal combustion engine may result in damage to the equipment, particularly premature breakage of a crankshaft of the internal combustion engine and/or destruction of the rotor. [0004] Examples of the invention seek to provide an improved rotor which overcomes or at least alleviates disadvantages associated with existing rotors. Summary of the Invention [0005] In accordance with one aspect of the present invention, there is provided a rotor including an inner member arranged for coupling to a rotational drive and an outer H:\sbt\Interwoven\NRPortbl\DCC\SBT\53979411 .doc- 15/08/2013 -2 member, wherein a flexible insert is interposed between the inner member and the outer member to absorb shock transmitted by the rotational drive. [0006] Preferably, the flexible insert is a rubber insert. [0007] Preferably, the flexible insert is endless. More preferably, the flexible insert is in the form of a circular ring. [0008] In a preferred form, the flexible insert has a centre which lies on an axis of rotation of the rotor. [0009] Preferably, the flexible insert is bonded to the inner member and the outer member. [00010] Preferably, the flexible insert is vulcanised into a gap between the inner member and the outer member. More preferably, the gap has a width of approximately 5mm. [00011] The rotor may be in the form of a fan, in which case the outer member may include fan blades. [00012] Preferably, the flexible insert is heat cured. [00013] Preferably, the rotational drive is a crankshaft of an internal combustion engine, and the inner member is coupled in direct drive relative to the crankshaft. More preferably, the inner member is directly connected to the crankshaft. The inner member may be in the form of a taper lock bushing which facilitates driven connection with the crankshaft. Even more preferably, the crankshaft is a crankshaft of an internal combustion engine, and the flexible insert is adapted to absorb torsional shock load from combustion pulses of the internal combustion engine. [00014] In a preferred form, the flexible insert is formed from rubber compound NR/SBR/BR 80 with nominal hardness 9443/4.

H:\sbt\Interwoven\NRPortbl\DCC\SBT\53979411 .doc- 15/08/2013 -3 [00015] In accordance with another aspect of the present invention, there is provided a fan assembly including an internal combustion engine and a rotor as described above, wherein a crankshaft of the internal combustion is in direct drive with the inner member, and the outer member includes fan blades such that the rotor operates as a fan. [00016] In accordance with another aspect of the present invention, there is provided a grain bunker system including a cover for covering grain and a fan assembly as described above, wherein the fan assembly is arranged to suck air from beneath the cover. Brief Description of the Drawings [00017] The invention is described, by way of non-limiting example only, with reference to the accompanying drawings, in which: [00018] Figure 1 shows an example of a fan assembly, comprising a rotor which is driven by an internal combustion engine; [00019] Figure 2 shows a hub and a taper lock bushing before a rubber compound is vulcanised into a gap between the components; [00020] Figure 3 shows an opposite side of the hub and taper lock bushing, after insertion of the rubber compound; [00021] Figure 4 shows a side view of a rotor including the components shown in Figure 3; [00022] Figure 5 shows an edge view of the rotor of Figure 4; [00023] Figure 6 shows a reverse side view of the rotor shown in Figure 4; [00024] Figure 7 shows diagrammatic side and cross-sectional edge views of a rotor without a flexible insert; [00025] Figure 8 shows comparable views to those of Figure 7 of a rotor with a flexible insert; H:\sbt\Interwoven\NRPortbl\DCC\SBT\53979411 .doc- 15/08/2013 -4 [00026] Figure 9 shows detailed views of a taper lock bushing having a flexible insert; [00027] Figure 10 shows a detailed side view of a rotor in accordance with another example of the present invention; [00028] Figure 11 shows a side perspective view of the rotor of Figure 10; and [00029] Figure 12 shows a detailed opposite side view of the rotor of Figure 10. Detailed Description [00030] With reference to Figures 1 to 9, there is shown a rotor 10 which incorporates a flexible insert 12. Advantageously, due to the presence of the flexible insert the rotor 10 is able to absorb torsional vibration so as to prevent or at least reduce damage to equipment resulting from operation of the rotor 10, particularly when the rotor 10 is in direct driven relationship with a crankshaft of an internal combustion engine. [00031] More specifically, the rotor 10 includes an inner member 14 arranged for coupling to a rotational drive 16 and an outer member 18, wherein the flexible insert 12 is interposed between the inner member 14 and the outer member 18 to absorb shock transmitted by the rotational drive 16. In this way, as the flexible insert 12 absorbs shock transmitted by the rotational drive 16, the flexible insert 12 introduces an element of dampening between the rotational drive 16 and the outer member 18 such that damage to the rotor 10 and/or the rotational drive 16 is reduced. More specifically, the applicant has identified that the flexible insert 12 is particularly suitable in dampening torsional shock due to firing pulses of an internal combustion engine powering the rotational drive 16 such that the incidence of failure of the rotational drive 16 or the rotor 10 is greatly reduced or eliminated. [00032] The flexible insert 12 may be in the form of a rubber insert, and may be an endless circular ring as shown in Figures 3, 4, 6 and 8. The flexible insert 12 may be configured so as to have a centre which lies on an axis of rotation of the rotor 10 such that the rotor 10 and the flexible insert 12 are concentric. This may be achieved by vulcanising the material of the flexible insert 12 into a gap 20 (see Figure 2) between the inner H:\sbt\Interwoven\NRPortbl\DCC\SBT\53979411 .doc- 15/08/2013 -5 member 14 and the outer member 18. In the example shown, the gap 20 has a width of approximately 5mm, however in alternative examples the gap 20 may have different widths. In this way, the flexible insert 12 is bonded to the inner member 14 and the outer member 18 such that the flexible insert 12 is able to transmit drive from the inner member 14 to the outer member 18, though with sufficient dampening to absorb shock due to combustion pulses of an internal combustion engine 22 (see Figure 1) powering the rotational drive 16. As the flexible insert 12 is circular and concentric with the rotor 10, it allows the inner member 14 to rotate relative to the outer member 18 to a small degree so as to absorb the torsional pulse vibrations transmitted by the rotational drive 16 to the inner member 14. [00033] The internal combustion engine 22 may be in the form of a diesel engine, the crankshaft of which forms the rotational drive 16 which is in direct driving connection with the rotor 10. The rotor 10 may be in the form of a fan 24, in which case the outer member 18 includes fan blades 26 (see Figure 5). Together with the internal combustion engine 22, the rotor 10 forms a fan assembly 28 which can be used to extract air through a duct 30 from beneath a cover of a grain bunker system so as to reliably create a negative pressure under the cover, sucking the cover to the grain beneath the cover to prevent flapping/tearing of the cover in windy conditions, therefore saving on grain spoilage, costly cover repairs and down labour time. The fan assembly 28 may include a shroud 32 which surrounds the rotor 10. [00034] The inner member 14 may be in the form of a taper lock bushing 34 which itself includes an inner tapered part 36 and an outer tapered part 38. The inner tapered part 36 fits in sleeved relationship within the outer tapered part 38, and is able to be driven into the outer tapered part 38 by way of outer screws 40 which are tightened so as to drive the inner tapered part 36 into the outer tapered part 38 thereby tightening a grip of the inner tapered part 36 around the crankshaft of the internal combustion engine 22. In order to remove the rotor 10 from the crankshaft, the screws 40 are removed, and a screw may be inserted and driven into threaded aperture 42 so as to drive apart the inner tapered part 36 and the outer tapered part 38.

H:\sbt\Interwoven\NRPortbl\DCC\SBT\53979411 .doc- 15/08/2013 -6 [00035] As shown in Figure 3, the flexible insert is formed from a rubber compound and sits between the outer tapered part 38 and the outer member 18. The flexible insert may be heat cured, and may be formed from rubber compound NR/SBR/BR80 with nominal hardness 9443/4. In alternative examples, the flexible insert 12 may be formed from other materials. [00036] Figure 6 shows detail of the flexible insert 12 interposed between the outer tapered part 38 and the outer member 18. Also shown is the manner in which the blades 26 are fitted to the rotor 10. [00037] Figure 7 shows a hub 44 and a rotor 10 without a flexible insert 12, whereas Figure 8 shows a similar hub 44 and rotor 10 including a flexible insert 12, for comparison purposes. Further detail of the taper lock bushing 34 is shown in Figure 9, with detailed views of the inner tapered part 36 shown from different views. Figure 9 also shows detail of a screw 40 as well as the location of the flexible insert 12 between the outer tapered part 38 and the outer member 18. [00038] Figures 10 to 12, show a rotor 10 in accordance with an alternative example, similar to the rotor of Figures 1 to 9 except with a modification to provide additional strength to ensure the hub does not fail through shear of the flexible insert 12. The rotor 10 of Figures 10 to 12 has features similar to the rotor of Figures 1 to 9, and like features are labelled with like reference numerals. [00039] In particular, the inner member 14 has a plurality of evenly spaced protrusions 46 welded at evenly spaced locations about its perimeter, and a series of corresponding recesses 48 are machined into the inner surface of the outer member 18. Each of the protrusions 46 is received within a corresponding one of the recesses 48, as shown in Figures 10 and 11. The flexible insert 12 is located between the inner member 14 and the outer member 18, including between the protrusions 46 and the recesses 48, such that the inner member 14 does not directly contact the outer member 18. [00040] As shown in Figure 12, the protrusions 46 need not extend along the entire axial length of the inner member 14, or may be tapered as they extend along the axial H:\sbt\Interwoven\NRPortbl\DCC\SBT\53979411 .doc- 15/08/2013 -7 length of the inner member 14 such that they are not pronounced in the view depicted in the Figure. Advantageously, the protrusions 46 and corresponding recesses 48 prevent/limit excessive rotation of the inner member 14 relative to the outer member 18 by compressing the flexible insert 12 therebetween, preventing or at least reducing the likelihood of the flexible insert 12 failing in a circular tear. In one particular example, the protrusions 46 may have a depth of approximately half an inch, extending part-way along the axial length of the inner member 14. [00041] While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not by way of limitation. It will be apparent to a person skilled in the relevant art that various changes in form and detail can be made therein without departing from the spirit and scope of the invention. Thus, the present invention should not be limited by any of the above described exemplary embodiments. [00042] The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates. [00043] Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and 'comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

Claims (22)

1. A rotor including an inner member arranged for coupling to a rotational drive and an outer member, wherein a flexible insert is interposed between the inner 5 member and the outer member to absorb shock transmitted by the rotational drive.

2. A rotor as claimed in claim 1, wherein the flexible insert is a rubber insert.

3. A rotor as claimed in claim 1 or claim 2, wherein the flexible insert is endless. 10

4. A rotor as claimed in claim 3, wherein the flexible insert is in the form of a circular ring.

5. A rotor as claimed in any one of claims 1 to 3, wherein the flexible insert has a 15 centre which lies on an axis of rotation of the rotor.

6. A rotor as claimed in any one of claims 1 to 5, wherein the flexible insert is bonded to the inner member and the outer member. 20

7. A rotor as claimed in any one of claims 1 to 6, wherein the flexible insert is vulcanised into a gap between the inner member and the outer member.

8. A rotor as claimed in claim 7, wherein the gap has a width of approximately 5mm. 25

9. A rotor as claimed in any one of claims 1 to 8, wherein the rotor is in the form of a fan, and the outer member includes fan blades.

10. A rotor as claimed in any one of claims 1 to 9, wherein the flexible insert is heat cured. 30 H:\sbt\Interwoven\NRPortbl\DCC\SBT\5397941_1.doc-15/08/2013 9

11. A rotor as claimed in any one of claims 1 to 10, wherein the rotational drive is a crankshaft of an internal combustion engine, and the inner member is coupled in direct drive relative to the crankshaft. 5

12. A rotor as claimed in claim 11, wherein the inner member is directly connected to the crankshaft.

13. A rotor as claimed in claim 11, wherein the crankshaft is a crankshaft of an internal combustion engine, and the flexible insert is adapted to absorb torsional 10 shock load from combustion pulses of the internal combustion engine.

14. A rotor as claimed in any one of claims 1 to 13, wherein the flexible insert is formed from rubber compound NR/SBR/BR 80 with nominal hardness 9443/4.

15 15. A rotor as claimed in any one of claims 1 to 14, wherein the inner member is in the form of a taper lock bushing.

16. A rotor as claimed in any one of claims 1 to 15, wherein the inner member has at least one radial protrusion, the outer member has at least one radial recess, and 20 said at least one protrusion is received by said at least one recess with said flexible insert interposed therebetween.

17. A rotor as claimed in claim 16, wherein the inner member has a plurality of circumferentially spaced radial protrusion, the outer member has a corresponding 25 plurality of circumferentially spaced radial recesses, and each of said protrusions is received by a corresponding one of said recesses with said flexible insert interposed therebetween.

18. A fan assembly including an internal combustion engine and a rotor as claimed in 30 any one of claims 1 to 17, wherein a crankshaft of the internal combustion is in H:\sbt\Interwoven\NRPortbl\DCC\SBT\5397941_1.doc-15/08/2013 10 direct drive with the inner member, and the outer member includes fan blades such that the rotor operates as a fan.

19. A grain bunker system including a cover for covering grain and a fan assembly as 5 claimed in claim 18, wherein the fan assembly is arranged to suck air from beneath the cover.

20. A rotor substantially as hereinbefore described with reference to the accompanying drawings. 10

21. A fan assembly substantially as hereinbefore described with reference to the accompanying drawings.

22. A grain bunker system substantially as hereinbefore described with reference to 15 the accompanying drawings.