GB2344398A

GB2344398A - Heavy-duty torsional-vibration damper

Info

Publication number: GB2344398A
Application number: GB9928445A
Authority: GB
Inventors: Joerg Sandig; Lutz Janner; Jens Herrmann; Joachim Conseur
Original assignee: Hasse and Wrede GmbH
Current assignee: Hasse and Wrede GmbH
Priority date: 1998-12-01
Filing date: 1999-12-01
Publication date: 2000-06-07
Anticipated expiration: 2019-12-01
Also published as: DE19855420C2; GB2344398B; KR20000052393A; JP2000199544A; KR100688134B1; DE19855420A1; GB9928445D0

Abstract

A heavy-duty torsional-vibration damper 1 has a housing 2 which comprises walls defining an annular channel. An annular bearing is provided supporting an annular flywheel 10 which is enclosed on all sides. The flywheel 10 is supported in the housing 2 by means of a bearing device 12 consisting of at least two layers of material (15, 16, 17) connected to one another. By this means it is possible to design the heavy-duty torsional-vibration damper for trouble-free running-times of more than 60,000 hours of operation. The materials are chosen as a function of, in particular, the mass of the flywheel and the damping medium which is used.

Description

2344398 Heavy-duty torsional-vibration damper The present invention

relates to a heavy-duty torsional-vibration damper, in particular for slow running main engines of ships, with a flywheel rim which is supported in a housing by means of a bearing device.

Torsional-vibration dampers consist, quite generally, of an annular, hermetically sealed housing which is flange-mounted on the side opposite the power side of a crankshaft to be damped. A flywheel rim is fitted in the housing, with close clearance. The gaps remaining between the flywheel rim and housing are filled with a damping medium, in particular with highly viscous silicone oil. In the event of torsional vibration, relative rotations are produced between the flywheel rim and the housing surrounding it, which intermittently shear the damping medium in the rhythm of the vibrations. This fluctuating shear deformation brings about a cushioning and damping effect To execute the relative rotation, the flywheel rim has to be rotatably supported in the housing. To this end, DE-PS 951 965 provides a bronze bearing ring, the outer cylindrical surface of which is in close contact with a corresponding inner surface of the flywheel rim and is connected to said flywheel rim.

EP 0 787 925 A2 discloses a heavy-duty torsional vibration damper which comprises a housing having walls. The walls define an annular channel in which a flywheel rim is rotatably received; an annular bearing is provided in the central bore of the flywheel rim and also an annular bearing support made of low-wear material is provided between the annular bearing and the inner wall of the channel. The low-wear material is a hardened metal.

In practice, however, it has become evident that the heavy-duty torsional-vibration dampers that are known from these publications are extremely trouble-prone.

The bearing elements of heavy-duty torsional-vibration dampers have to be adjusted or interchanged in disadvantageous manner prior to expiration of the expected trouble-free running-time of about 60,000 hours of operation. In view of the restricted spatial conditions in the engine room of the ship, such a repair proves to be difficult, on account of the large masses to be moved and the lack of powerful hoists.

EP 0 009 981 Bi discloses a torsional-vibration damper, the flywheel rim of which is radially supported on a sleeve consisting of polytetrafluoroethylene (PTFE) which bears against a hub flange of the housing.

However, the support of the flywheel rim by means of a PTFE sleeve as described in this printed publication is unsuitable in the case of heavy-duty torsional vibration dampers, since the load-carrying capacity of the PTFE sleeve is exceeded.

In contrast, it is desirable to develop a heavy duty torsional-vibration damper in such a manner as to make it largely trouble-free.

The invention is defined in claim 1, to which reference should now be made. Further, advantageous embodiments are found in the dependent claims.

As a result of the formation of the bearing device from at least two layers of material which are connected to one another in a laminated fashion, it is possible to design the heavy-duty torsional-vibration damper according to the invention for a trouble-free running-time of more than 60,000 hours of operation.

In this connection it is possible to choose the materials in question as a function of, for example,".

the mass of the flywheel and the damping medium used.

The bearing device which is provided in the heavy duty torsional-vibration damper according to the invention has to bear and guide the annular flywheel or flywheel rim. Therefore the layers of material advantageously comprise a low-friction and/or low-wear industrial material. A particularly good load-carrying capacity of the bearing device is achieved if at least one of the layers of material consists of a metallic material. A particularly low-friction bearing device is achieved if at least one layer of material consists of synthetic material, in particular a polyfluorocarbon. The polyfluorocarbon may be selected from, in particular, PTFE, polychlorotrifluoroethylene (PCTFE) or polytetrafluoroethyleneperfluoropropylene (PFEP). As a result of the use of a synthetic material, the bearing device of the heavy-duty torsional-vibration damper according to the invention can, advantageously, both accommodate the large forces and endure the vibrational movements at high temperatures which occur during operation of the torsional-vibration damper. Aggregates that increase the wear resistance, in particular bronze particles, glass fibres, graphite, charcoal or aromatic polyesters, can be admixed to the synthetic material, in particular to the polyfluorocarbon.

A particularly advantageous heavy-duty torsional vibration damper comprises a bearing device with a layer of material consisting of a metallic material, on the upper (or radially outer) side of which and on the under (or radially inner) side of which a layer of material consisting of synthetic material, in particular a polyfluorocarbon, is respectively located.

In this case the metal layer serves as a supporting layer for the bearing device which is provided in the form of a sliding layer between the flywheel rim and housing of the heavy-duty torsional -vibration damper.

The layers of synthetic material preferably each exhibit a layer thickness of just a few tenths of a millimetre The bearing device consisting of at least two connected layers of material may take the form of a bearing ring which is located between the flywheel rim and at least one part of the housing of the heavy-duty torsional-vibration damper. If the corresponding part of the housing is the thrust bearing of the heavy-duty torsional-vibration damper, then radial guidance of the flywheel rim is advantageously achieved. On the other hand, if the corresponding part of the housing is the rear wall or the cover plate of the torsional-vibration damper, then axial guidance of the flywheel in the heavy-duty torsional-vibration damper is achieved.

Combined radial and axial guidance of the flywheel rim is achieved in advantageous manner when at least one bearing surface projects from the bearing ring.

This is the case, in particular, when the bearing ring and a bearing surface projecting from it form a bearing bushing which is substantially L-shaped in cross section.

It has proved advantageous to arrange the bearing device in floating manner between the flywheel rim and the housing.

Further features and advantages of the present invention will become apparent from the following description of exemplary embodiments thereof with reference to the figures, in which Figure 1 represents a part of a first embodiment of the heavy-duty torsional-vibration damper according to the invention in perspective view, partially cut away, Figure 2 represents a part of the bearing device that is provided in Figure 1 in an enlarged view, Figure 3 represents a part of an alternative embodiment of the heavy-duty torsional vibration damper according to the invention in perspective view, partially cut away, and Figure 4 represents a part of another embodiment of the heavy-duty torsional-vibration damper according to the invention in perspective view, partially cut away.

The term 'heavy-duty torsional-vibration dampers, may be understood to mean, in particular, devices for shear-gap elimination having outside diameters amounting (for example) to about 1.5 to 3.0 m. Their total mass amounts to 3 to 20 tonnes. Dampers of this size are customarily flange-mounted onto the crankshafts of slow-running two-stroke cross-head engines with 5 to 13 cylinders and a piston diameter of 350 to 900 mm. In most applications such an engine drives the propeller of an ocean-going vessel directly, i.e. without interposed elastic coupling or transmission. It is self-evident that the heavy-duty torsional-vibration damper according to the invention may, in particular, exhibit other dimensions and masses and may also be provided for other end uses.

In Figure 1 a part of a heavy-duty torsional vibration damper 1 is represented by way of example.

It comprises a housing 2 and a rear wall 3 from which there project a housing shell 4 and a thrust bearing 5.

on the thrust bearing 5 there is arranged a fastening flange 6, with which the heavy-duty torsional-vibration damper 1 can be fastened to an engine crankshaft which is not shown here, pertaining for example to a main 3S engine of a ship or to a stationary internal-combustion engine taking the form of a slow-running engine. The housing 2 is closed by a cover plate 7 by means of symbolically represented screws 8 which are distributed over the outer and inner perimeters of the cover plate 7. With a view to sealing the housing 2, a sealing element 9 is fitted in the end faces of the housing shell 4 and the thrust bearing 5, respectively. The sealing element 9 in the example represented here is an O-ring, but other sealing elements may also be provided. Alternatively or additionally it is possible to provide a seal by means of liquid sealants which are applied by brush on the contact surfaces of housing shell 4 and cover plate 7 and also of thrust bearing 5 and cover plate 7.

A flywheel rim 10 is located in the housing 2.

Between flywheel rim 10, rear wall 3, housing shell 4 and cover plate 7 shear gaps 11 are present in which a damping medium, for example highly viscous silicone oil, is located. The inner periphery of the flywheel rim 10 in Figure 1 is radially supported on a bearing or bearing device 12 which rests on the thrust bearing 5. In the embodiment shown here the bearing device 12 takes the form of a strip-like bearing ring 13 which extends in the axial direction from the rear wall 3 as far as the cover plate 7 of the housing 2 and is arranged in floating manner.

With a view to axial guidance of the flywheel rim 10, buffers 14, known in the art, which are formed in mushroom-like or disc-shaped manner, are fastened to its flanks, facing the rear wall 3 and also the cover plate 7.

Section A which is indicated in Figure 1 is represented on an enlarged scale in Figure 2. In the example which has been chosen, the bearing ring 13 is constructed from three layers of material 15, 16 and 17. The middle layer of material 15 which is represented in Figure 2 consists of metal and serves as supporting layer for the layers of material 16 and 17 which are located below and above, respectively, the layer of material 15, or, to be more exact, radially inside and radially outside. The layers of material 16 and 17 are each formed from a suitable synthetic material, in particular a polyfluorocarbon, for example PTFE. The layers of material 16 and 17 are pressure resistant and low-friction, so that the flywheel rim 10, which bears with its inner bore against the layer of material 17, can slide easily by means of the bearing ring 13 on the thrust bearing 5 of the housing 2, against which the layer of material 16 bears. The layers of material 16 and 17 consisting, for example, of polyfluorocarbon serve, so to speak, as contact layers of the bearing device 12 in relation to the flywheel rim 10 and the thrust bearing 5. With a view to increasing the wear resistance of the synthetic layers of material 16 and 17 aggregates such as, for example, bronze particles, glass fibres, graphite, charcoal or aromatic polyesters may be admixed to them.

In the example represented here the layer of material 15 consisting of metal is of thicker construction than the layers of material 16 and 17 which consist of a synthetic material and which exhibit a thickness of, in each case, just a few tenths of a millimetre. In particular, the layer of material 15 consisting of a metal may exhibit a thickness of about 0.3 mm, and the sliding layers which are laminated on both sides of said layer of material may each exhibit a thickness of 0.5 mm, or vice versa. However, this is not mandatory; rather, depending on the intended application, any material thicknesses of the individual layers of material 15, 16 and 17 may be provided.

In Figure 3 an embodiment of the heavy-duty torsional-vibration damper 1 that has been modified in comparison with Figure 1 is represented. Axial support of the flywheel rim 10 is now no longer effected by means of buffers 14, but by means of two additional bearing rings 131 and 13" which are arranged between the bearing ring 10 and the rear wall 3 and between the flywheel rim 10 and the cover plate 7 of the housing 2, and which extend over the entire inner circumference of the flywheel rim 10 perpendicular to the first bearing ring 13. By way of example, the bearing rings 131 and 13" are constructed, just like the bearing ring 13, from a layer of material 15 consisting of metal and from two layers of material 16 and 17 surrounding said layer of material 15 and made of a synthetic material, possibly a polyfluorocarbon, as already described, in such a way that the layers of material 16 and 17 rest on the rear wall 3 and on the flywheel rim 10 in the case of the bearing ring 131 or on the cover plate 7 and on the flywheel rim 10 in the case of the bearing ring 13".

In the example shown in Figure 3 the bearing rings 131 and 13" are not connected to the bearing ring 13.

In contrast, in Figure 4 two bearing rings 13 radially supporting the flywheel rim 10 are provided, to each of which a bearing ring 131 and 13" axially guiding the flywheel rim 10 is integrally fitted. Consequently, the flywheel rim 10 is supported axially and radially by means of two substantially L-shaped flange bushings, as seen in partial cross-section. Hence, in advantageous manner, not only torsional vibrations to be damped but also radial and axial accelerations can be accommodated.

The bearing rings 131 and 13" guarantee not only axial support of the flywheel rim 10 that is as low wear as possible, but they also maintain the lateral shear gaps 11 which are filled with the highly viscous silicone oil serving as a damping medium. The supply of the shear gaps 11 with highly viscous silicone oil is particularly effective if - as shown in Figure 4 two bearing rings 13 which are spaced from one another and which provide radial support of the flywheel rim 10 are provided, since the damping medium which is located in a store or reservoir 18 can easily get into the shear gaps 11 via this spacing.

For facilitated assembly of the bearing device 12, there may be one or more slots provided in the bearing rings 13, 131 and/or 13".

List of Reference Symbols 1 Heavy-duty torsional-vibration damper 2 Housing 3 Rear wall 4 Housing shell Thrust bearing 6 Fastening flange 7 Cover plate 8 Screws 9 Sealing elements Flywheel rim 11 Shear gaps 12 Bearing device 13, 131, 13" Bearing ring 14 Buffers Layer of material 16 Layer of material 17 Layer of material 18 Store

Claims

1. A heavy-duty torsional-vibration damper (1) having a housing (2), an annular flywheel (10) mounted in the housing (2) and a bearing device (12) on which the flywheel is mounted, characterised in that the bearing device (12) comprises at least two laminated layers of material (15, 16 or 15, 17).

2. A heavy-duty torsional-vibration damper (1) according to claim 1, in which the layers of material (15, 16, 17) comprise a low-friction and/or low-wear and/or pressure-resistant industrial material.

is

3. A heavy-duty torsional-vibration damper (1) according to claim 1 or 2, in which at least one layer of material (15, 16, 17) consists of a metallic material.

4. A heavy-duty torsional-vibration damper (1) according to any of claims 1 to 3, in which at least one layer of material (15, 16, 17) consists substantially of a synthetic material, preferably a polyfluorocarbon.

5. A heavy-duty torsional-vibration damper (1) according to claim 4, in which aggregates increasing wear resistance are located in the layer (15, 16, 17) made of synthetic material.

G. A heavy-duty torsional-vibration damper (1) according to claim 4 or 5, in which the layer or layers of material (15, 16, 17) consisting of synthetic material take the form of a contact layer which bears against the flywheel rim (10) and/or the housing (2).

7. A heavy-duty torsional-vibration damper (1) according to any preceding claim, in which the bearing device (12) comprises a layer of material (15) consisting of a metallic material andtaking the form of a supporting layer, on the upper side and underside of which a layer of material (16, 17) consisting of a synthetic material, in particular a polyfluorocarbon, is located.

8. A heavy-duty torsional-vibration damper (1) according to any preceding claim, in which the bearing device (12) comprises at least one bearing ring (13, 131, 13") which is located between the flywheel rim (10) and at least one part of the housing (2).

is

9. A heavy-duty torsional-vibration damper (1) according to claim 8, in which the bearing ring (13, 131, 13") is of strip-like or cylindrical form.

10. A heavy-duty torsional-vibration damper (1) according to claim 8 or 9, in which at least one additional bearing ring (131, 13") which is likewise a component of the bearing device (12) projects from the first bearing ring (13).

ii. A heavy-duty torsional-vibration damper (1) according to claim 10, in which the bearing ring (13) and the bearing ring (131, 13") projecting from it form a bearing bushing which is substantially L-shaped in partial cross-section in such a way that the first bearing ring (13) supports the flywheel (10) radially and the bearing ring (131, 13") projecting from it supports the flywheel (10) axially.

12. A heavy-duty torsional-vibration damper (1) according to any preceding claim in which the bearing device (12) is arranged in floating manner between the flywheel rim (10) and housing (2).

13. A heavy-duty torsional-vibration damper (1) according to any preceding claim, in which buffers (14) serving as axial support for the flywheel rim (10) are provided on the flywheel rim (10) and/or on the housing (2).

14. A heavy-duty torsional-vibration damper substantially according to one of the embodiments described in the description and/or shown in the Figures.