WO1992001600A1 - Propeller hub - Google Patents

Propeller hub Download PDF

Info

Publication number
WO1992001600A1
WO1992001600A1 PCT/DK1991/000211 DK9100211W WO9201600A1 WO 1992001600 A1 WO1992001600 A1 WO 1992001600A1 DK 9100211 W DK9100211 W DK 9100211W WO 9201600 A1 WO9201600 A1 WO 9201600A1
Authority
WO
WIPO (PCT)
Prior art keywords
hub
projections
gap
inner hub
propeller
Prior art date
Application number
PCT/DK1991/000211
Other languages
French (fr)
Inventor
Jack Skrydstrup
Original Assignee
Gori Af 1902 As
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Gori Af 1902 As filed Critical Gori Af 1902 As
Publication of WO1992001600A1 publication Critical patent/WO1992001600A1/en

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63H—MARINE PROPULSION OR STEERING
    • B63H23/00—Transmitting power from propulsion power plant to propulsive elements
    • B63H23/32—Other parts
    • B63H23/34—Propeller shafts; Paddle-wheel shafts; Attachment of propellers on shafts

Definitions

  • the invention concerns a hub in particular for a marine propeller and comprising an inner hub adapted to be firmly mounted on a drive shaft, a propeller carrying outer hub concentrically arranged around the inner hub with a gap, and an elastomeric bushing arranged in the gap and connected with the inner hub as well as the outer hub by means of e.g. adhesion or vulcanization.
  • the elastomeric bushing which is usually made of rubber, acts in this connection as a shock absorber which serves to prevent overloadings that might cause rupture or other damage to the propeller or the transmission system to it.
  • the rubber bushing must be relatively soft and elastic, and it will hereby in itself constitute a weak link in the power transmission. It has been found in many cases that the rubber bushing eventually fails, and if it fails at an inconvenient time, e.g. under adverse weather conditions at sea, this may have very serious consequences since the ship will now be disabled and left to drift about at the mercy of wind and waves.
  • the object of the invention is to provide a hub of the type mentioned in the opening paragraph, which is so adapted that the torsion torque to which the elastomeric bushing is subjected, is kept within a predetermined maximum size, and that the power transmission between the drive shaft and the propeller is maintained even if the elastomeric bushing fails.
  • the hub of the invention is characterized in that the elastomeric bushing extends axially only along part of the gap, and that at least one radially outwardly extending projection on the inner hub is firmly mounted at the side of the bushing in said gap and correspondingly at least one radially inwardly extending projection on the outer hub, the combined radial extent of two associated projections being greater than the radial width of the gap, and that these projection overlap each other in the longitudinal direction of the drive shaft and are positioned at a mutual angular distance at least in the rest position of the propeller.
  • the inner hub and the outer hub may each have at least two projections arranged at equidistant angular distances, and each projection on the inner hub may be positioned substantially centrally between two projections on the outer hub at least in the rest position of the propeller.
  • the elastomeric bushing may have such a torsional stiffness that only at propeller loads above normal, such as switching at full speed, it is twisted so much that associated projections are brougth into mutual contact.
  • each projection may converge in the radial direction of the extent of the projection, so that the cantilevered projections obtain a great strength against bending, and the faces serving to transfer the forces between the projections will simultaneously have an advantageously large extent.
  • the projections on the inner hub may be an integral part of it, but for manufacturing reasons they may also be firmly arranged on a separate ring, which is in turn firmly mounted on a pin constituting an axial extension of the inner hub.
  • the separate ring may be firmly mounted on the pin via an intermediate ring of an elastic material, such as rubber, or may itself consist of an elastic material having a relatively great strength, e.g. rubber or plastics.
  • the inner hub may be provided with an axial extension in the form of a pin which is rotatably journaled in a bearing provided in the outer hub in the vicinity of its projection, and this bearing may accommodate a bushing which is made of an electrically insulating material, such as plastics, to prevent electrolytic corrosion of the components of the hub.
  • fig. 1 is a perspective exploded view of a marine hub according to the invention.
  • fig. 2 is an axial section through the marine hub shown in fig. 1,
  • fig. 3 is a section along the line III-III in fig. 2, with the hub shown in the rest position of the propeller, and the projection of the inner hub provided on a separate ring,
  • fig. 5' shows the hub of fig. 3, but in a second embodiment where an intermediate ring of an elastic material is interposed between the separate ring and the inner hub, and
  • fig. 6 shows the same, but with the inner hub rotated so much that associated projections are in mutual contact.
  • Fig. 1 shows a propeller hub generally designated by 1.
  • the propeller hub comprises an inner hub 2 and an outer hub 3 carrying a propeller 4, which is a foldable pro ⁇ peller in this case, but may otherwise be of any con- struction.
  • the inner hub 2 may be mounted firmly on a drive shaft 5, only the outermost end of which being show .
  • a rubber bushing 6 is firmly vulcanized on the inner hub 2, which extends axially past the bushing with the pin 7, which has a four-sided member 8 closest to the bushing and a cylindric member 9 at the end.
  • a separate ring 10 which has a four-sided hole 11 mating with the four-sided member 8 of the pin 7, as well as two projections or bosses 12.
  • Fig. 1 also shows a plas ⁇ tics ring 13 with a circular hole 14 mating with the cylindrical member 9 on the pin 7, as well as a control ring 20.
  • Part of the outer hub 3 has been cut away in fig. 1, so that a projection or a boss 15 as well as a hole 16 are visable in the interior of the hub.
  • the hole 16 serves as a guide for a cylindrical part 17 on the plastics ring 13.
  • the outer hub 3, in mounted state, is provided concentrically around the inner hub 2 with a gap 18 which is axially only partly filled by the bushing 6, which is firmly vulcanized or adhered to both the inner hub and the outer hub.
  • the separate ring 10 with its four-sided hole 11 is pressed firmly on t e four-sided member 8 of the cylindrical pin 7, and the cylindrical member 9 of the pin 7 is rotatably journaled in the plastics ring 13, which is in turn pressed into the guide hole 16 of the outer hub 3.
  • the inner hub 2 is thus kept securely controlled in the outer hub 3 by means of this mount 13, the rubber bushing 6 and the control ring 20.
  • figs. 3 and 4 show the propeller hub from the end, partly in section.
  • both the inner hub and the outer hub each has two opposed bosses.
  • Fig. 3 shows the positions of these bosses in the rest position of the propeller, the bosses 12 of the inner hub being positioned centrally between the bosses 15 of the outer hub 3.
  • the propeller has now been loaded so much that the bosses 12 of the inner hub 2 are in contact with the bosses 15 of the outer hub 3. The propeller can function in this position, even if the rubber bushing 6 is destroyed.
  • an intermediate ring 19 of e.g. rubber having a relatively great strength is interposed between the ring 10 and the four-sided member 8 on the pin 7, as shown in figs. 5 and 6.
  • the inner hub 2 can rotate additionally slightly with respect to the outer hub 3 after the bosses 12 and 15 have contacted each other, the relatively thin rubber ring 19 being deformed by the action of compressive forces which do not tend to destroy the rubber material of the ring. If such a destruction should nevertheless occur, the hub will still be functio ⁇ nal, because the forces will instead be transferred directly between the four-sided member 8 of the pin 7 and "the four-sided hole 11 of the ring 10.
  • the bosses 15 of the outer hub 3 have a shape which tapers in a direction inwardly toward the centre of hub.
  • the bosses hereby obtain a great moment of resistance to bending and large engagement faces to receive the forces which are to be transferred via the bosses.
  • the bosses 12 may be constructed in the same advantageous manner.
  • the inner hub and the outer hub may each just have one boss, and these bosses are positioned diametrically opposite each other in the rest position of the propeller. This enables particularly great torsion of the two hub parts with respect to each other before the two bosses hit each other and substantially take over the power transmission.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • Ocean & Marine Engineering (AREA)
  • Motor Power Transmission Devices (AREA)

Abstract

A hub (1) in particular for marine propellers (4) comprises an inner hub (2) adapted to be firmly mounted on a drive shaft (5), an outer hub (3) arranged about said inner hub with a gap (18) and carrying the propeller (4), and an elastomeric bushing (6) arranged in the gap (18) and connected with both the inner hub (2) and the outer hub (3) by means of e.g. adhesion or vulcanization. The elastomeric bushing (6) extends axially only along part of the gap (18), and at least one radially outwardly extending projection (12) on the inner hub (2) is firmly mounted in the gap (18) at the side of the elastomeric bushing (6) and correspondingly at least one radially inwardly extending projection (15) on the outer hub (3). The combined radial extent of the associated projections (12, 15) is greater than the radial width of the gap (18), and the projections (12, 15) moreover overlap each other in the longitudinal direction of the drive shaft and are positioned at a mutual angular distance at any rate in the rest position of the propeller. The torsional moment to which the elastomeric bushing (6) is subjected is hereby restricted to a predetermined maximum size, so that the bushing is never overloaded and is thus not liable to be destroyed, and the power transmission between the drive shaft (5) and the propeller (4) is maintained under any circumstances, even if the elastomeric bushing (6) should fail.

Description

Propeller hub
The invention concerns a hub in particular for a marine propeller and comprising an inner hub adapted to be firmly mounted on a drive shaft, a propeller carrying outer hub concentrically arranged around the inner hub with a gap, and an elastomeric bushing arranged in the gap and connected with the inner hub as well as the outer hub by means of e.g. adhesion or vulcanization.
In operation, propellers for ships are frequently sub¬ jected to sudden and violent changes in load. This takes places e.g. when switching from ahead to astern, or if in rough sea the propeller is momentarily lifted out of the water. In hubs of the above-mentioned type the elastomeric bushing, which is usually made of rubber, acts in this connection as a shock absorber which serves to prevent overloadings that might cause rupture or other damage to the propeller or the transmission system to it. To perform this function effectively, the rubber bushing must be relatively soft and elastic, and it will hereby in itself constitute a weak link in the power transmission. It has been found in many cases that the rubber bushing eventually fails, and if it fails at an inconvenient time, e.g. under adverse weather conditions at sea, this may have very serious consequences since the ship will now be disabled and left to drift about at the mercy of wind and waves.
The object of the invention is to provide a hub of the type mentioned in the opening paragraph, which is so adapted that the torsion torque to which the elastomeric bushing is subjected, is kept within a predetermined maximum size, and that the power transmission between the drive shaft and the propeller is maintained even if the elastomeric bushing fails.
This is achieved in that the hub of the invention is characterized in that the elastomeric bushing extends axially only along part of the gap, and that at least one radially outwardly extending projection on the inner hub is firmly mounted at the side of the bushing in said gap and correspondingly at least one radially inwardly extending projection on the outer hub, the combined radial extent of two associated projections being greater than the radial width of the gap, and that these projection overlap each other in the longitudinal direction of the drive shaft and are positioned at a mutual angular distance at least in the rest position of the propeller. This effectively prevents overloading of the elastomeric bushing and simultaneously ensures that the propeller can continue to operate even in those cases where the bushing might be destroyed.
In a particularly advantageous embodiment of the invention the inner hub and the outer hub may each have at least two projections arranged at equidistant angular distances, and each projection on the inner hub may be positioned substantially centrally between two projections on the outer hub at least in the rest position of the propeller.
Moreover, according to the invention, to obtain a cushioning as great as possible the elastomeric bushing may have such a torsional stiffness that only at propeller loads above normal, such as switching at full speed, it is twisted so much that associated projections are brougth into mutual contact.
Further, the side faces of each projection may converge in the radial direction of the extent of the projection, so that the cantilevered projections obtain a great strength against bending, and the faces serving to transfer the forces between the projections will simultaneously have an advantageously large extent.
The projections on the inner hub may be an integral part of it, but for manufacturing reasons they may also be firmly arranged on a separate ring, which is in turn firmly mounted on a pin constituting an axial extension of the inner hub.
When, in case of great loads, or when the elastomeric bushing is destroyed, the projections begin to function, this might in certain cases take place with such a great force that this per se can cause damage, if the projections are mounted completely non-resiliently on both the inner hub and the outer hub. To overcome this drawback the separate ring may be firmly mounted on the pin via an intermediate ring of an elastic material, such as rubber, or may itself consist of an elastic material having a relatively great strength, e.g. rubber or plastics.
Furthermore, to obtain good control between the outer hub and the inner hub, the inner hub may be provided with an axial extension in the form of a pin which is rotatably journaled in a bearing provided in the outer hub in the vicinity of its projection, and this bearing may accommodate a bushing which is made of an electrically insulating material, such as plastics, to prevent electrolytic corrosion of the components of the hub.
The invention will be explained more fully by the following description of embodiments, which just serve as examples, with reference to the drawing, in which
fig. 1 is a perspective exploded view of a marine hub according to the invention. fig. 2 is an axial section through the marine hub shown in fig. 1,
fig. 3 is a section along the line III-III in fig. 2, with the hub shown in the rest position of the propeller, and the projection of the inner hub provided on a separate ring,
fig- - shows the same, but with the inner hub rotated so much that associated projections are in mutual contact,
fig. 5' shows the hub of fig. 3, but in a second embodiment where an intermediate ring of an elastic material is interposed between the separate ring and the inner hub, and
fig. 6 shows the same, but with the inner hub rotated so much that associated projections are in mutual contact.
Fig. 1 shows a propeller hub generally designated by 1. The propeller hub comprises an inner hub 2 and an outer hub 3 carrying a propeller 4, which is a foldable pro¬ peller in this case, but may otherwise be of any con- struction. The inner hub 2 may be mounted firmly on a drive shaft 5, only the outermost end of which being show .
A rubber bushing 6 is firmly vulcanized on the inner hub 2, which extends axially past the bushing with the pin 7, which has a four-sided member 8 closest to the bushing and a cylindric member 9 at the end. There is moreover pro¬ vided a separate ring 10 which has a four-sided hole 11 mating with the four-sided member 8 of the pin 7, as well as two projections or bosses 12. Fig. 1 also shows a plas¬ tics ring 13 with a circular hole 14 mating with the cylindrical member 9 on the pin 7, as well as a control ring 20.
Part of the outer hub 3 has been cut away in fig. 1, so that a projection or a boss 15 as well as a hole 16 are visable in the interior of the hub. The hole 16 serves as a guide for a cylindrical part 17 on the plastics ring 13.
As shown best in fig. 2, the outer hub 3, in mounted state, is provided concentrically around the inner hub 2 with a gap 18 which is axially only partly filled by the bushing 6, which is firmly vulcanized or adhered to both the inner hub and the outer hub. The separate ring 10 with its four-sided hole 11 is pressed firmly on t e four-sided member 8 of the cylindrical pin 7, and the cylindrical member 9 of the pin 7 is rotatably journaled in the plastics ring 13, which is in turn pressed into the guide hole 16 of the outer hub 3. The inner hub 2 is thus kept securely controlled in the outer hub 3 by means of this mount 13, the rubber bushing 6 and the control ring 20.
The mutual arrangement of the respective bosses 12, 15 is shown more clearly in figs. 3 and 4, which show the propeller hub from the end, partly in section. In this case, both the inner hub and the outer hub each has two opposed bosses. Fig. 3 shows the positions of these bosses in the rest position of the propeller, the bosses 12 of the inner hub being positioned centrally between the bosses 15 of the outer hub 3. In fig. 4, the propeller has now been loaded so much that the bosses 12 of the inner hub 2 are in contact with the bosses 15 of the outer hub 3. The propeller can function in this position, even if the rubber bushing 6 is destroyed.
If the bosses 12, 15 are firmly mounted on the inner hub 2 and the outer hub 3, respectively, without any possibility of yielding when they hit each other in case of great propeller loads, very great forces can occur, which themselves can damage the propeller or the mecha¬ nical parts of the hub. To obtain a softer deceleration of the relative movements of the inner hub and the outer hub, an intermediate ring 19 of e.g. rubber having a relatively great strength is interposed between the ring 10 and the four-sided member 8 on the pin 7, as shown in figs. 5 and 6.
Therefore, as shown in fig. 6, the inner hub 2 can rotate additionally slightly with respect to the outer hub 3 after the bosses 12 and 15 have contacted each other, the relatively thin rubber ring 19 being deformed by the action of compressive forces which do not tend to destroy the rubber material of the ring. If such a destruction should nevertheless occur, the hub will still be functio¬ nal, because the forces will instead be transferred directly between the four-sided member 8 of the pin 7 and "the four-sided hole 11 of the ring 10.
As shown figs. 3-6, the bosses 15 of the outer hub 3 have a shape which tapers in a direction inwardly toward the centre of hub. The bosses hereby obtain a great moment of resistance to bending and large engagement faces to receive the forces which are to be transferred via the bosses. Of course, the bosses 12 may be constructed in the same advantageous manner.
An embodiment with two bosses on the inner hub and two bosses on the outer hub is described above and shown in the drawing. Of course, embodiments with another number of bosses are conceivable within the scope of the invention. Thus, the inner hub and the outer hub may each just have one boss, and these bosses are positioned diametrically opposite each other in the rest position of the propeller. This enables particularly great torsion of the two hub parts with respect to each other before the two bosses hit each other and substantially take over the power transmission.

Claims

P a t e n t C l a i m s:
1. A hub (1), in particular for marine propellers ( ), comprising an inner hub (2) adapted to be firmly mounted on a drive shaft (5), a propeller (4) carrying outer hub (3) concentrically arranged around the inner hub with a gap (18), and an elastomeric bushing (6) arranged in the gap (18) and connected with the inner hub (2) as well as the outer hub (3) by means of e.g. adhesion or vulcani¬ zation, c h a r a c t e r i z e d in that the elastomeric bushing (6) extends axially only along part of the gap (18), and that at least one radially outwardly extending projection (12) on the inner hub (2) is firmly mounted at the side of the bushing (6) in said gap and correspond¬ ingly at least one radially inwardly extending projection (15) on the outer hub (3), the combined radial extent of two associated projections (12, 15) being greater than the radial width of the gap (18), and that said projections (12, 15) overlap each other in the longitudinal direction of the drive shaf (5) and are positioned at a mutual angular distance at least in the rest position of the propeller (4).
2. A hub according to claim 1, c h a r a c t e r i z e d in that the inner hub (2) and the outer hub (3) each has at least two projections (12, 15) arranged at equidistant angular distances, and that each projection (12) on the inner hub (2) is positioned substantially centrally between two projections (15) on the outer hub (3) at least in the rest position of the propeller (4).
3. A hub according to claim 1 or 2, c h a r a c t e r ¬ i z e d in that the elastomeric bushing (6) has such a torsional stiffness that only in case of propeller loads above normal, such as switching at full speed, it is twisted so much that associated projections (12, 15) are brougth into mutual contact.
4. A hub according to claim 1, 2 or 3, c h a r a c t e r- i z e d in that the side faces of each projection (12,
15) converge in the radial direction of the extent of the projection.
5. A hub according to one or more of claims 1 - 4, c h a r a c t e r i z e d in that the projections (12) on the inner hub (2) are an integral part of it.
6. A hub according to one or more of claims 1 - 4, c h a r a c t e r i z e d in that the projections (12) of the inner hub (2) are firmly arranged on a separate ring (10), which is in turn firmly mounted on a pin (7) constituting an axial extension of the inner hub.
7. A hub according to claim 6, c h a r a c t e r i z e d in that the separate ring (10) is firmly mounted on the pin (7) via an intermediate ring (19) of an elastic material, such as rubber.
8. A hub according to claims 6 or 7, c h a r a c t e r - i z e d in that the separate intermediate ring (19) consists of an elastic material having a relatively great strength, e.g. rubber or plastics.
9. A hub according to one or more of claims 1 - 8, c h a r a c t e r i z e d in that the inner hub (2) is formed with an axial extension in the form of a pin (7), which is rotatably journaled in a bearing (16) provided in the outer hub (3) in the vicinity of its projections (15).
10. A according to claim 9, c h a r a c t e r i z e d in that the bearing (16) has a bushing (13) which is made of - lo ¬
an electrically insulating material, such as plastics.
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PCT/DK1991/000211 1990-07-18 1991-07-17 Propeller hub WO1992001600A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DK172390A DK164780C (en) 1990-07-18 1990-07-18 propeller hub
DK1723/90 1990-07-18

Publications (1)

Publication Number Publication Date
WO1992001600A1 true WO1992001600A1 (en) 1992-02-06

Family

ID=8107538

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/DK1991/000211 WO1992001600A1 (en) 1990-07-18 1991-07-17 Propeller hub

Country Status (3)

Country Link
AU (1) AU8237591A (en)
DK (1) DK164780C (en)
WO (1) WO1992001600A1 (en)

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3047074A (en) * 1960-10-24 1962-07-31 Marine Propeller Company Cushioned marine propeller mounting
SE227666C1 (en) * 1970-07-07
US3563670A (en) * 1969-01-31 1971-02-16 Brunswick Corp Marine propeller and its mounting
GB1409911A (en) * 1971-09-08 1975-10-15 Volvo Penta Ab Method of assembling a propeller hub
US4310285A (en) * 1977-12-09 1982-01-12 Outboard Marine Corporation Folding propeller with rubber hub
SE452973B (en) * 1983-12-19 1988-01-04 Brunswick Corp STOT-ABSORBING PROPELLER

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE227666C1 (en) * 1970-07-07
US3047074A (en) * 1960-10-24 1962-07-31 Marine Propeller Company Cushioned marine propeller mounting
US3563670A (en) * 1969-01-31 1971-02-16 Brunswick Corp Marine propeller and its mounting
GB1409911A (en) * 1971-09-08 1975-10-15 Volvo Penta Ab Method of assembling a propeller hub
US4310285A (en) * 1977-12-09 1982-01-12 Outboard Marine Corporation Folding propeller with rubber hub
SE452973B (en) * 1983-12-19 1988-01-04 Brunswick Corp STOT-ABSORBING PROPELLER

Also Published As

Publication number Publication date
DK164780C (en) 1992-12-28
DK172390D0 (en) 1990-07-18
DK172390A (en) 1992-01-19
DK164780B (en) 1992-08-17
AU8237591A (en) 1992-02-18

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