WO2011150972A1

WO2011150972A1 - Bearing support structure

Info

Publication number: WO2011150972A1
Application number: PCT/EP2010/057768
Authority: WO
Inventors: Mohamed Zeid
Original assignee: Berg Propulsion Production Ab
Priority date: 2010-06-03
Filing date: 2010-06-03
Publication date: 2011-12-08

Abstract

The present invention relates to a bearing support structure (1 ) for a flexible coupling arrangement in a propulsion shafting system arranged to a foundation (40). The foundation may be subject to static and/or dynamic flexural movements, in particular in an aircraft, marine or industrial environment. The support structure (1) comprises a pair of support surfaces (2) and one or more connectors(3) for connecting the support arrangement to the foundation along a connection length (E). The connection length (E), as measured along the full length of the one or more connectors (3) in the axial direction of the distance (D), is less than a distance (D) between the support surfaces (2), whereby the impact from any movement of the foundation on the vertical and angular relationship between the support surfaces may be restricted. The present invention provides for a cheap yet sturdy system for restricting deflections or deformations of the hull from being transferred to the propulsions shafts.

Description

BEARING SUPPORT STRUCTURE

TECHNICAL FIELD

The invention relates to a support structure for a flexible coupling arrangement in a propulsion shafting system arranged to a foundation which may be subject to static and/or dynamic flexural movements, in particular in an aircraft, marine or industrial environment, said support structure comprising

- a pair of support surfaces being arranged with a distance from each other in a axial direction, and intended to support the shafting system on each side of a flexible coupling in a fixed vertical and angular relationship, and

one or more connectors for connecting the support arrangement to the foundation along a connection length.

The invention also relates to a flexible coupling arrangement in a propulsion shafting system.

BACKGROUND OF THE INVENTION

Coupling arrangements for propulsion shafting systems are used e.g. in aircraft, marine and industrial applications for coupling shafts so as to transmit torque while

accommodating axial and/or misalignment of the shafts.

One prior known type of coupling arrangement uses flexible couplings integrated with the solid shafts so as to transmit the torque. Such couplings are often stiff in torsion and radial directions, but flexible in axial and angular directions, and can handle angular differences of about 0.5 to 1 degree. For handling larger angular misalignments, a plurality of such couplings are necessary, e.g. four couplings for a misalignment of 4 degrees. Accordingly, this type of solution might become rather expensive.

Another solution for handling relatively large misalignments is to use a cardan shaft. In view of the above, there is room for improvement in the field of flexible coupling arrangements for propulsion shafting systems.

SUMMARY OF THE INVENTION

The object of the invention is to provide an alternative flexible coupling arrangement. Preferably, the arrangement should be reliable and/or be an economical alternative to present solutions.

To this end, it is desired to use a flexible coupling in the form of a torsional vibration coupling (or torsional vibration damper) between the shafts. This type of coupling is flexible in radial, torsional, angular and axial directions. However, to ensure reliable operation of the torsional vibration coupling, the coupling should be protected from excessive lateral vibrations. Moreover, the inclination angle of the two shafts should be restricted, so as to ensure the coupling performance. These two requirements are rendered more difficult to achieve since the foundation to which the flexible coupling should be arranged, e.g. the hull of a vessel, is typically subject to static and/or dynamic flexural movements.

In view of the above, a new support structure for a flexible coupling arrangement in a propulsion shafting system is proposed.

In a first aspect, the invention comprises a bearing support structure for a flexible coupling arrangement in a propulsion shafting system arranged to a foundation which may be subject to static and/or dynamic flexural movements, in particular in an aircraft, marine or industrial environment,

said support structure comprising

a pair of support surfaces being arranged with a distance from each other in a axial direction, and intended to support the shafting system via bearings on each side of a flexible coupling in a fixed vertical and angular relationship, and

Furthermore, said connection length , as measured along the full length of said one or more connectors in the axial direction of the distance, is to be less than the distance between the support surfaces, whereby the impact from any movement of the foundation on the vertical and angular relationship between the support surfaces may be restricted.

The proposed support structure is intended to support the shafts of a shafting system on both sides of a flexible coupling via its support surfaces, for example via bearings arranged thereon. It is desired that the support surfaces are maintained in a fixed vertical and angular relationship, so as to control the above-mentioned aspects of the coupling.

To this end, it has been found to be advantageous, if the connector or connections of the support structure to the foundation has a total connection length to the foundation along the shafting system being less than the distance between the support surfaces. The portion of the foundation directly underneath the respective support surfaces may be subject to flexural movement, which means that the angular and vertical relationship between the portions of the foundation directly underneath the two support surfaces is not fixed. However, the impact of these differences may be diminished by approaching the utmost connection points to the foundation to each other. As the connection length to the foundation diminishes, any misalignment between the support surfaces caused by movements in the foundation diminishes.

In this context, the connection length is to be understood as the full length between the two utmost connection points between the connector(s) and the foundation, regardless of whether there is a single connector or several separate connectors.

In another aspect of the invention, there is provided a bearing support structure for a flexible coupling arrangement in a propulsion shafting system arranged to a foundation which may be subject to static and/or dynamic flexural movements, in particular in an aircraft, marine or industrial environment,

said support structure comprising

a pair of support surfaces (being arranged with an axial distance from each other, and intended to support the shafting system via bearings on each side of a flexible coupling in a fixed vertical and angular relationship. Moreover, the support structure comprises a single connector for connecting the support structure to the foundation, , said connector being associated with both support surfaces, whereby the impact from any movement of the foundation on the vertical and angular relationship between the support surfaces may be restricted. Similarly to the first aspect, the second aspect of the invention relies on the idea that the impact of the flexural movement of the foundation on the relationship between the support surfaces need to be considered. In this second aspect, it is proposed to use a single connector for connecting the support structure to the foundation, wherein said connector is carrying both support surfaces. In other words, the support structure is intended to move as a single unit, including the support surfaces and the connector. Hence, the impact of the movement of the foundation on the vertical and angular relationship between the support surfaces will be restricted.

Preferably, the single connection has a connection length as measured in the axial direction of the distance between the support surfaces being less than the distance between the support surfaces. In such an embodiment, the advantages of the first and the second aspect of the invention are combined, resulting in a support structure being highly suitable for restricting the impact of the movement of the foundation on the vertical and angular relationship between the support surfaces.

Advantageously, the connection length has an extension being less than than 75 % of the axial distance between the support surfaces, preferably less than 50% of the axial distance between the support surfaces, most preferred less than 25% of the axial distance between the support surfaces.

Preferably, the support structure could form a general Y-shape. In this case, the base of the Y may form the connection to the foundation, and the arms of the Y carries the support surfaces, which will be axially separated , wherein said support structure forms a general Y-shape.

Advantageously, the support surfaces may be arranged in a vertical relationship so as to be on different vertical height from said foundation. Advantageously, the support surfaces may be arranged in a vertical relationship so as to be on an substantially equal vertical height from said foundation. Advantageously, the respective planes of the two support surfaces are arranged in with an angular relationship in the range -10 to +10, preferably -6 to +6, more preferably -3 to +3 degrees. With angular relationship is meant the angle formed between the planes of the two support surfaces.

The two support surfaces could form different angles with respect to an axial plane.

However, it is generally preferred if the respective planes of the two support surfaces are arranged to form essentially the same angle with an axial plane. Advantageously, the axial distance between the support surfaces may be between 100 and 1 100 mm, preferably between 300 and 900 mm.

In another aspect, the invention comprises an arrangement providing a flexible coupling in a propulsion shafting system comprising a support structure in accordance with any one of the previous claims, wherein said pair of support surfaces support a pair of bearings.

Preferably, said pair of bearings s arranged with a vertical relationship between the bearings so as to be on an essentially equal vertical height from said foundation. Advantageously, said pair of bearings is arranged so as to form an angular relationship between the bearings in the range -10 to +10, preferably -6 to +6, more preferably -3 to +3 degrees.

Preferably, said bearings support shafts of the propulsion shafting system, said shafts being interconnected via a flexible coupling arranged in between said bearings. Most preferred, said flexible coupling is a torsional vibration coupling.

Advantageously, said shafts have a diameter in the range 50-500 mm, advantageously 50-200 mm, more advantageously 75-150 mm, preferably about 100 mm.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention will now be described with reference to the enclosed exemplary drawings, wherein: Fig. 1 illustrates an embodiment of a support structure when forming part of an

arrangement including a flexible coupling in a propulsion shafting system;

Fig. 2 is a front view of the support structure of Fig. 1 , without the propulsion shafting system;

Fig. 3 is a side view of the support structure of Fig. 2;

Fig. 4 is a front view of a second embodiment of a support structure;

Fig. 5 is a front view of a third embodiment of a support structure;

Fig. 6 is a front view of a fourth embodiment of a support structure.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The invention will, in the following, be exemplified by embodiments. It should however be realized that the embodiments are included in order to explain principles of the invention and not to limit the scope of the invention, defined by the appended claims. Details from two or more of the embodiments may be combined with each other.

Fig. 1 illustrates an embodiment of a bearings support structure 1 which supports a propulsion shafting system. The bearing support structure is hereafter referred to as the support structure. The propulsion shafting system comprises two shafts 10, suitably a driving shaft and a driver shaft. For interconnecting the shafts a flexible coupling 30 is arranged between them. The support structure 1 supports the shafting system via bearings 20 provided one on each shaft 10 and on each side of the flexible coupling 30.

Advantageously, the flexible coupling may be a torsional vibration coupling.

The support structure 1 is connected to a foundation 40, which could be e.g. the hull of a vessel. The invention is primarily intended for environments where the foundation 40 may be subject to flexural movement, such that is the case e.g. for moving vessels. Generally, the structure may conveniently be formed by using a central connector element 3, carrying a pair of arms 4, which in turn defines the support surfaces 2.

Fig. 2 is a front view of the support structure of Fig. 1 , without the propulsion shafting system. The support structure comprises a pair of support surfaces 2 for supporting the shafts 10 of the shafting system on either side of a flexible coupling 30. To this end, the support surfaces 2 are separated by an axial distance D. With the axial distance D is meant the distance between the centers of each of the support surfaces and along a generally axial direction. A generally axial direction would in this context be a direction in a plane substantially parallel to the foundation 40.

The support structure also comprises one connector 3, although more connectors for connecting the support structure to the foundation 40 are possible. The connector 3, or connectors, are connected to the foundation along a full length in the axial direction which is referred to as the connection length E. It is to be noted that the axial direction of the connection length E is the same direction as the axial direction of the distance D between the support surfaces 2.

The embodiment illustrated in Fig. 2 incorporates both of the alternative solutions proposed herein. Accordingly, it is believed to be particularly advantageous although, as shall be explained in the below, the two solutions are also believed to provide an advantage over prior art when used separately.

First, the connection length E of the connector 3 is less than the axial distance D between the support surfaces 2. This means that any flexural movement of the foundation 40 to which the support structure 1 is to be attached, has a lesser impact on the relationship between the support surfaces 2 than what would be the case, should e.g. each support surfaces 2 be supported by a separate straight pillar connected to the foundation 40. This may be understood if considering a movement of the foundation 40, creating a height difference in the foundation 40, i.e. a temporary but continuous difference on hull deflection due to e.g. different loading/operating conditions, e.g. different power levels of the engine.

If for example using two conventional, straight connectors, each connector carrying a support surface, and the connectors forming a connection length E being equal to the axial distance D, to support the shafting system, the deflection, or deformation, in the foundation 40 can reach the first connector before it reaches the second connector or a deformation can be temporarily positioned there between. Hence, the relationship between the support surfaces may be disturbed by the deflection. By diminishing the connection length E, the difference in the movement of the connectors caused by the change of operating conditions, loadings or the like, will be diminished, whereby the relationship between the support surfaces will be stabilized. If the connectors located sufficiently close together, i.e. having a sufficiently short connection length, they will essentially perform a similar movement when such operating conditions change; such that the relationship between the support surfaces is substantially unaffected by what would otherwise be a sudden misalignment.

The maximum extension of the connection length E in order to achieve sufficient stability between the support surfaces may depend on a number of factors such as the stiffness of the foundation 40, the flexion to which it may be subject, and the stiffness and design of the connectors. However, generally, the shorter the connection length E, the better.

Fig. 5 illustrates an embodiment where the axial extension E is less than the axial distance D between the support surfaces 2. In the illustrated embodiment, the support structure 1 moreover comprises two separate parts, each part having a connector 3 associated with a support surface 2. It is understood that the connection length E is regarded as the full length of the connection to the foundation 40, regardless of any empty space between individual connectors 3. A structure 1 as described in Fig. 5 may be more vulnerable to flexion in the foundation 40 than e.g. the embodiment of Fig. 2, it would perform better than a conventional approach, and could be sufficient for certain environments.

In the embodiments illustrated herein, the connection length E of the connector 3 to the foundation 40 is located vertically in between the support surfaces 2. This is normally preferred from a space saving perspective. However, the geometry of the support structure 1 could be designed such that all or one connector 3 is located vertically beside the support surfaces 2, i.e. at the side of the axial distance D. Still, a total length of the connector or connectors 3 should be less than the axial distance D between the support surfaces. In other words; for the capability of withstanding flexion in the foundation 40, it is not relevant where the connection to the foundation is located.

Returning to the embodiment of Fig. 2, this embodiment also incorporates the second aspect of the invention, namely that there is a single connector 3 to the foundation 40, which single connector 3 is associated with both support surfaces 2. It will be understood, that a single connector 3 will, if affected by a flexion wave in the foundation, move as a single unit which will restrict the impact of the wave on the relationship between the two support surfaces 2.

It will be understood, that the capacity of the support structure 1 to move as single unit will be affected e.g. by the connection length E to the foundation 40, the flexion to which the foundation 40 is subject, and the stiffness and shape of the connector 3. Fig. 3 shows a side a view of the support structure in Fig. 2. In this case, the connector 3 is a single steel rod having a square formed cross section generally with a diameter corresponding to the diameter of the shaft it is intended to support. Other shapes of cross sections are of course possible, such a circular, rectangular, polygonal or the like. As illustrated in Fig. 6, embodiments could be envisaged using a relatively large and stiff single connector 3, which per se is sufficient to dampen any flexion in the foundation 40 such that the relationship between the support surfaces 2 is generally unaffected by said flexion. However, for most practical embodiments, it is believed to be most advantageous to combine the first and second aspects of the invention, as illustrated e.g. in Fig. 2. This means that the support structure should advantageously comprise a single connector 3 whose connection length E in the axial direction is less than the distance D between the support surfaces 2. In such embodiments, the combined effect of the single connector and the relatively small connection length will cooperate so as to diminish the impact of any flexion in the foundation 40 on the relationship between the support surfaces 2.

Accordingly, in the embodiment of Fig. 2, a single connector 3 is used. Moreover, the single connector 3 has a connection length E being less than 25% of the distance D between the support surfaces 2. Generally, the structure may conveniently be formed by using a central connector element 3, carrying a pair of arms 4, which in turn defines the support surfaces 2. As exemplified in the drawings, a general Y-shape has been found to be suitable for this type of construction. Regardless of which aspect of the invention is concerned, one or both of the support surfaces may form an angle in relation to the foundation 40 in order to take up any angular misalignment of the shafting system. As illustrated in Fig. 4, the angles a1 , a2 may preferably the equal, as this enables a favorable load distribution on the supported shafts and coupling. However, embodiments where the angles a1 , a2 of the two support surfaces 2 are different are also conceivable. Figure 4 also shows support surfaces 2b on the arms 4 illustrating the interval of the angles a1 , a2 between positive angles and negative angles, the horizontal plane, in this case parallel with the foundation 40, being at zero degrees.

Advantageously, support structures may be manufactured and marketed with various angular differences such that a customer may select a proper support structure for his/her situation. Support structures with a fixed angular relationship may be made relatively inexpensive and reliable.

However, it is envisaged that the support structure could include some adjustment system with which the angles of the support surfaces could be varied, such that one support structure could be used for setting a desired angular difference between the surfaces. The angles may be changed by inserting or retracting angular adjustment plates between the support surfaces 2 and the bearings 20. For example, a plate of sheet metal having a first thickness of 2 mm at one end and a second thickness of 5 mm at a second end could be used to manipulate the tilting of the bearings, and thus achieve the desired misalignment between the bearings 20. The bearings 20 can also comprise level tilting adjustment means such as screw arrangements.

The Length D between the bearings and the diameter 0 of the shafts is advantageously so that the relationship below is fulfilled:

where X is 100 - 400. Example:

If the length D between the bearings is 1000 mm, the diameter 0 The support structure could be formed from any convenient material, in particular steel and marine steel, although carbon fiber material or carbon fiber reinforced material is possible.

Claims

1. A bearing support structure (1 ) for a flexible coupling arrangement in a propulsion shafting system arranged to a foundation (40) which may be subject to static and/or dynamic flexural movements, in particular in an aircraft, marine or industrial environment,

said support structure (1) comprising

a pair of support surfaces (2) being arranged with a distance (D) from each other in a axial direction, and intended to support the shafting system (10, 10) via bearings on each side of a flexible coupling (30) in a fixed vertical and angular relationship, and

one or more connectors(3) for connecting the support arrangement to the foundation along a connection length (E),

characterised by

said connection length (E), as measured along the full length of said one or more connectors (3) in the axial direction of the distance (D), being less than the distance (D) between the support surfaces (2), whereby the impact from any movement of the foundation on the vertical and angular relationship between the support surfaces may be restricted.

2. A bearing support structure for a flexible coupling arrangement in a propulsion shafting system arranged to a foundation which may be subject to static and/or dynamic flexural movements, in particular in an aircraft, marine or industrial environment,

said support structure comprising

a pair of support surfaces (2) being arranged with a axial distance from each other, and intended to support the shafting system via bearings on each side of a flexible coupling (30) in a fixed vertical and angular relationship, and

characterised by

- a single connector (3) for connecting the support structure (1 ) to the foundation,

, said connector (3) being associated with both support surfaces (2), whereby the impact from any movement of the foundation on the vertical and angular relationship between the support surfaces may be restricted.

3. The bearing support structure according to claim 2, wherein said single connector (3) has a connection length (E) for connection to the foundation (40), as measured in the axial direction of the distance (D), being less than the distance (D) between the support surfaces (2).

4. The bearing support structure in accordance with claim 1 or 3, wherein said

connection length (E) has an extension being less than 75 % of the axial distance (D) between the support surfaces, preferably less than 50% of the axial distance (D) between the support surfaces, most preferred less than 25% of the axial distance (D) between the support surfaces.

5. The bearing support structure in accordance with claim 4, wherein said support structure has the general shape of the letter Y.

6. The bearing support structure in accordance with any one of the previous claims, wherein the support surfaces (2) are arranged in a vertical relationship so as to be on an essentially equal vertical height from said foundation (40).

7. The bearing support structure in accordance with any one of the previous claims, wherein the respective planes of the two support surfaces (2) are arranged in with an angular relationship in the range -10 to +10, preferably -6 to +6 degrees, more preferably -3 to +3 degrees.

8. The bearing support structure in accordance with any one of the previous claims, wherein the respective planes of the two support surfaces (2) are arranged to form essentially the same angle (a1 , a2) with a axial plane.

9. KSC The bearing support structure in accordance with any one of the previous claims, wherein the axial distance (D) between the support surfaces (2) is between 100 and 1 100 mm, preferably between 300 and 900 mm.

10. "^Arrangement providing a flexible coupling in a propulsion shafting system comprising a bearing support structure in accordance with any one of the previous claims, wherein said pair of support surfaces (2) support a pair of bearings (20).

11. X Arrangement in accordance with claim 1 1 , wherein said pair of bearings (20) is arranged so as to be on different vertical height from said foundation (40).

512. Arrangement in accordance with claim 1 1 or 12, wherein said pair of bearings is arranged so as to form an angular relationship (a1 + a2) between the bearings in the range -10 to +10, preferably -6 to +6 degrees, more preferably -3 to +3 degrees.

13. ^Arrangement in accordance with any one of claims 1 1 to 12, wherein said bearings0 (20) support shafts (10) of the propulsion shafting system, said shafts (10) being interconnected via a flexible coupling (30) arranged in between said bearings (20).

14. D5 Arrangement in accordance with claim 14, wherein said flexible coupling (30) is a torsional vibration coupling.

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15. Wi Arrangement in accordance with claim 14 or 15, wherein said shafts (10) have a diameter in the range 50-200 mm, preferably about 100 mm. 0

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