GB2261930A

GB2261930A - Resiliently mounted thrust bearing

Info

Publication number: GB2261930A
Application number: GB9224643A
Authority: GB
Inventors: Oliver Simon; Herbert Rzepus
Original assignee: Blohm and Voss GmbH
Current assignee: Blohm and Voss GmbH
Priority date: 1991-11-26
Filing date: 1992-11-25
Publication date: 1993-06-02
Anticipated expiration: 2012-11-25
Also published as: GB9224643D0; DE4138708C2; DE4138708A1; GB2261930B

Abstract

An arrangement for the resilient mounting of a combined thrust and support bearing (10) (Fig 1), in particular for a ship's propulsion plant, with a mount foundation positioned at the middle of the shaft, with resilient pressure segments arranged in the support region of the thrust and support bearing in the mount flanges for receiving the deformation forces which act on the bearing from the outside, and with pressure segments with rubber elastic damping elements (103) prestressed between metal plates (101, 102) is characterised in that a chamber forming cut-out is provided in each case in the confronting end faces of the metal plates (101, 102) into which a rubber elastic damping element (103) can be fitted, in that boundary surfaces (105, 106) directed perpendicular to the metal plate plane are provided in the edge region of the cut-outs and distributed around the periphery, and in that the rubber elastic damping element (103) which is in each case fittable into the cut-out of the metal plates forms a unitary damping body. <IMAGE>

Description

22,51 ?-),j C_ t_ Arrancrement for the resilient mountinq of a combined

thrust and s"Dort bearing, in Particular for a ship's propulsion plant The invention relates to an arrangement for the elastic mounting of a combined pressure and carrying mount, in particular for a ship's propulsion plant, in accordance with the preamble of patent claim 1.

Arrangements of pressure and carrying mounts for a shaft train for a ship's propulsion plant are exposed to manyfold external deformation forces and influences. It is thus obvious to equip arrangements of pressure and carrying mounts with elastic mounts and pressure segments in order to deviate the deformation forces which act from the outside, e.g. due to pitching and rolling movements, and also to alleviate the peak loadings which arise under "hogging and sagging" conditions. such arrangements are also used to alleviate alternating loadings through damping measures. In this way it is possible to avoid damage to the propulsion plants due to deformation.

Arrangements of this kind are known from ship building. German Offenlegungsschrift 35 22 188 Al shows, for example, a support between the cover plate of the ship's foundation and a base plate of an axially thrust loaded ship propulsion engine, the base plate containing an axial thrust bearing. In this arrangement the base plate contacts the foundation plate via fitted pieces and a plastic intermediate layer and is fixedly positioned with screw fastenings via vertically standing sheet metal thrust plates.

A resilient mounting of a steering engine with rubberbonded-to-metal sandwich components is known from German Patent 30 14 799 C2. The advantage of a resilient mounting based on the use of prestressed rubberbonded-to-metall rubber buffer arrangements lies in the fact that an arrangement of this kind can be used in a spacially compact embodiment to pick up pressure forces from all sides in the axial and radial direction. Moreover, the mounting can act as a result of the prestress as a rigid mount so long as the operating forces lie beneath the bias force. However, the resilient mounting comes into play when the forces which are acting exceed the prestress.

DE-PS 679 384 shows an arrangement for the resilient mounting of a propulsion engine for a vehicle with a resilient part inserted between a chassis part and an engine part and consisting of an annular concave/convex rubber block which is partly surrounded by a metallic sleeve which, together with the chassis part and the engine part, forms a ring-like resilient chamber.

DE-PS 857 894 shows a resilient mounting for a propulsion unit with a ring-like arrangement of rubber segments which are vulcanised flat between clamping bands which enclose the transmission housing in a semi- circular manner in two planes perpendicular to the transmission axis. The drive unit connected to the clamping band has the possibility of moving relatively freely with respect to the ring-like carrying part, whereby an effective damping is obtained of the vibrations transmitted from the motor.

The object of the invention is to provide an improved resilient mounting for the thrust and support bearing, in particular of a ship's propulsion plant, with the aid of resilient pressure segments for the thrust and support bearing in order to absorb the enormous three-dimensionally directed forces which act from the outside on the support mount and to preclude irreversible deformations. In accordance with the object provision is made for the use of prestressed rubber elastic damping elements since suddenly occurring angular displacements and tilting movements must be expected as a result of the extreme deformation processes acting from the outside in the support region of the thrust and support bearing. The resilient mounting of the propulsion plant has the advantage that the propagation of structure-borne noise can be simultaneously suppressed.

This object is satisfied in accordance with the invention by a resilient mounting comprising first and second mounting members of a substantially rigid material and at least one resilient plate-like damping element disposed between said first and second mounting members characterised in that for each support member a cut-out is provided in each said mounting member with each cut-out having a base and inwardly facing side walls; in that said damping element is sandwiched between said bases of said cutouts of said first and second support member and in that said inwardly facing side walls of said cut-outs contact side walls of said damping element. A further way of satisfying this object in accordance with the invention comprises an arrangement for the elastic mounting of a combined thrust and support bearing, in particular for a ship's propulsion plant, a) with a mount foundation positioned at the shaft centre, b) with resilient pressure segments arranged in the support - 4 region of the thrust and support mount in the mount flanges for receiving the deformation forces which act on the mount from the outside, with pressure segments with rubber elastic damping elements prestressed between metal plates, characterised in that d) a chamber forming cut-out is provided in each case in the confronting end faces of the metal plates into which a rubber elastic damping element can be fitted, e) f) boundary surfaces directed perpendicular to the metal plate plane are provided in the edge region of the cut-outs and distributed around the periphery, the rubber elastic damping element which is in each case fittable into the cut-out of the metal plates forms a unitary damping body.

The arrangement for the resilient mounting of the thrust and support bearing comprises resilient pressure segments fixed in the mounting flanges of the support mount with rubber elastic plate-like damping elements each clamped between two metal plates. The metal plates of the thrust segments are on the one hand connected to the carrying part of the foundation, and on the other hand to the support part of the thrust and support bearing. The metal plates have respective cut-outs at the mutually confronting sides into which the individual rubber elastic damping element is fitted, with support surfaces directed perpendicular to the plane of the plate being provided for each damping element in the edge region of the cut-outs, at least over a part of their periphery. The support surfaces are intended to prevent parallel displacements between the plates. As a result of this chamber-like structure, the thrust loadings which act from the outside onto the metal plates are converted, in accordance with the invention, into pressure loadings of the rubber elastic material in the region of the support surface. In accordance with the invention this measure has decisive technical advantages since the prestressed rubber elastic damping body is considerably more resistent to pressure loading.

Furthermore, the containment of the rubber elastic material serves to largely prevent the characteristics of the rubber elastic material being impaired as a consequence of oil contamination.

In the following the invention will now be explained in more detail with reference to the accompanying drawings in which:

Fig. 1 shows a plan view of a thrust bearing for a propeller shaft of a ship, Fig. 2 shows a partial section on the plane II-II of Fig. 1, Fig. 3 shows a partial section on the plane III-III in Fig. 1, and Figs. 4 and 5 show enlarged views of parts of Figs. 2 and 3 respectively.

Turning firstly to Fig. 1 there can be seen a plan view of a thrust bearing 10 for the propeller shaft 12 of a ship's propulsion system. It will be appreciated that in a ship the propeller is located at the stern outside of the hull whereas the engine driving the propeller is located inside of the ship and is coupled to the propeller via a relatively 1 long shaft 12. In use, the thrust from the propeller has to be transmitted to the hull of the ship and this is done via a thrust bearing such as 10. Moreover, since provision is invariably made for reversing a ship and the thrust loading is reversed during reversing, the thrust bearing 10 is designed to accommodate thrust in both axial directions 14 and 16 of the propeller shaft.

In the thrust bearing of Fig. 1, the actual thrust loads are borne by four thrust mountings 18, 20, 22, and 24 which are all identically constructed. Each thrust mounting comprises a mounting member such as 26 which is screwed by means of eight anchor bolts such as 28 to a longitudinal beam (not shown) of the ship's hull. Interposed between the mountings 18, 20, 22 and 24 and the corresponding flange portions 30, 32, 34 and 36 of the housing 38 of the thrust bearing are respective resilient mountings 40, 42, 44 and 46. The arrangement of each resilient mounting between its mounting on the foundation of the ship and the flange portion of the thrust bearing housing 38 can be seen generally in more detail from Fig. 2 and to a larger scale in Fig. 4.

It can be seen from the drawing of Fig. 2.that each mounting such as 24 to the.foundation in the ship comprises a generally right-angled plate 50 with a triangular web 52, with a row of anchor screws 28 provided on each side of the web 52. Moreover, the drawing of Fig. 2 shows that the flange portion 36 actually comprises the axial side surfaces of top and bottom flanges 54 and 56 of the split thrust housing 38. The arrangement of the split thrust housing 38 can conveniently be seen from Fig. 3 and the top and bottom flanges 54 and 56 are readily evident at the right hand side of the drawing of Fig. 3.

The hollow propeller shaft 12 can be seen at the centre of the thrust housing 38 in Fig. 3 and it will be noted that a plurality of generally trapezoidally shaped thrust pads 58 are disposed around the propeller shaft. These thrust pads 58 can also be seen in the drawing of Fig. 1 abutting against a flange 60 of the propeller shaft 12 which is, however, not visible in Fig. 3. In fact, the drawing of Fig. 1 shows the thrust pads 58 at the top of the two-part thrust housing 38 on either side of the flange 60 of the propeller shaft, and indeed in the manner in which they can be seen through a top cover 62 of the thrust housing which is broken away at the left and right hand edges 64 and 66, but which normally extends over the rectangular array of bolt holes 68 so that the thrust pads would be hidden from view. The thrust pads are white-metalled bearings which run in oil and each have a rear mounting spigot 70 which allows them to be mounted in a self-aligning manner in a corresponding support structure of the thrust housing 38. The precise detail of the thrust bearing does not form part of the present invention and it will thus not be described in further detail. It will however be appreciated that the thrust segments 58 on both sides of the flange 60 are provided to cope with thrust in the two possible axial directions.

The flange portions 54 and 56 at the sides of the thrust housing 38 are connected together and to a ship's foundation 72 by a plurality of anchor bolts 74 which pass through the foundation 72, through a resilient mounting 78 provided beneath the flange portion 56, through a resilient mounting 80 provided above the flange portion 54, and through a spacer tube 82 which passes through the flange portions and part way through the top and bottom resilient mountings 78 and 80. The anchor bolts 74 are secured by respective nuts such as 84. The detail of the resilient mountings 78 and 80 of Fig. 3 can be seen to a larger scale in Fig. 5. It will be noted that the spacer tube can slide axially within the 1 flanges of the thrust housing and within the resilient mountings. Thus, although the mounting is effectively relatively rigid when forces act which lie below the prestress determined by the precompression of the rubber elements of the resilient mountings the flange portions can nevertheless move upwardly and downwardly relative to the anchor bolts 74 when loads arise above the prestress.

It will be appreciated from the above description that axial thrust loads acting on the thrust housing are principally borne by the resilient mountings 40, 42, 44 and 46 which are generally loaded in compression in the direction illustrated by the arrow 86 of the Fig. 2 and Fig. 4. Nevertheless, loading in the other directions is possible, for example in the direction of the arrow 88 of Fig. 4 when the hull of the ship is subjected to special deformations or shock loads.

The mountings 78 and 80 of Fig. 3 are primarily intended to accommodate loads acting in the direction of the arrow 90 of Fig. 5, but are also able to cope with loads acting, for example in the direction of the arrow 92 of Fig. 5.

The precise detail of the resilient mountings will now be discussed with reference to Figs. 4 and 5.

The arrangement of the resilient mount of Figs. 4 and 5 comprise rubber elastic damping elements 103, 113 which can be fitted into cut-outs 100 of the metal plates 101, 102 and 111, 112 respectively. The metal plates 101, 102, 111 and 112 are in turn connected on the one hand to the mounting or carrier 24 and on the other hand via set screws such as 107 to the flange portion or support part 56. With thrust or shockwave loading (Fig. 4), i.e. perpendicular to the plane of the metal plates 101, 102, i.e. in the direction of the arrow 86 or in the opposite direction, the damping elements 1 103 are loaded in compression. With parallel displacements of the two metal plates relative to one another, i.e. under the influence of external random forces perpendicular to the shaft axis, the loading of the rubber elastic damping elements 103 likewise takes place in compression on the path via the inner supporting surfaces 105 and 106 of the metal plates 101 and 102. The plate spacing 109 in the edge region of the metal plates 101, 102 amounts in the present case to 3.1 mm in the unclamped state and in the prestressed state to 2.5 mm. The setting of a prestress which is always predeterminable takes place for the damping elements 103 by driving in a clamping wedge 104 between the carrier 24 and the metal plate 102, which has a wedge surface complementary to that of the wedge 104.

In the support region of the damping segments III and 112 of Fig. 5 the shock-wave loading of the resilient mount takes place perpendicular to the shaft axis. A setting of the prestress for the damping elements 13 takes place via the clamping or anchor screws 74. Shock loadings, which act from the outside on the arrangement which lead to minimal mutual displacements of the two metal plates 111 and 112, are transmitted from the inwardly disposed support surfaces 115, 116 to the resilient damping elements 13 with simultaneous pressure loading.

j

Claims

Patent Claims:

Resilient mounting comprising first and second mounting members of a substantially rigid material and at least one resilient plate-like damping element disposed between said first and second mounting members, characterised in that a cut-out is provided in at least one of and preferably in each of said mounting members, with each cut-out having a base and inwardly facing side walls; in that said damping element is sandwiched between said bases of said cut-outs of said first and second mounting members, and in that said inwardly facing side walls of said cutouts contact side walls of said damping element.

2.

Resilient mounting in accordance with claim 1, characterised in that said first and second mounting members have confronting surfaces which are spaced apart from one another thus permitting a degree of compression of said damping element without-contact between said mounting members.

Resilient mounting in accordance with claim 1 or claim 2, characterised in that a plurality of damping elements is provided, and in that a corresponding number of cut-outs is provided in each of said mounting members.

4. Resilient mounting in accordance with any one of claim 1 to 3, characterised in that the or each said damping element is provided with one or more apertures, and in 11 that support means is provided for the side wall or walls of said aperture or apertures.

Resilient mounting in accordance with any one of claims 1 to 4, characterised in that means is provided for prestressing said damping element or elements.

6. Resilient mounting in accordance with any one of the preceding claims where first and second resilient mountings of like construction are provided on opposite sides of a flange means, optionally in the form of two or more adjacent flanges, and are secured by means of one or more anchor members to a foundation.

Resilient mounting in accordance with claim 6. characterised in that the or each said anchor member passes through both said resilient mountings and said _flange means into said foundation.

8. Resilient mounting in accordance with claim 7, characterised in that the or each said anchor member passes through a respective spacer tube, each said spacer tube passing through said flange means, through that respective mounting member of each resilient mounting wh-ich-contacts the flange means and abutting against a shoulder of the other resilient mounting member of each resilient mounting, said spacer tube being dimensioned to determine the prestress of each damping element.

9. Resilient mounting in accordance with any one of claims 1 to 6, wherein one of said mounting members is provided with a wedge surface; and in that a separate 1 a.

complementary wedge is provided which abuts the said wedge surface and determines, in dependence on its relative position to said wedge surface, the overall thickness of said resilient mounting and optionally also the prestress in said damping element or elements.

10. Arrangement for the elastic mounting of a combined thrust and support bearing, in particular for a ship's propulsion plant, a) with a mount foundation positioned at the shaft centre, b) with resilient pressure segments arranged in the support region of the thrust and support mount in the mount flanges for receiving the deformation forces which act on the. mount- from the outside, c) with pressure segments with rubber elastic damping elements prestressed between metal plates, characterised in that d) a chamber forming cut-out is provided in each case in the confronting end faces of the metal plates into which a rubber elastic damping element can be fitted, e) boundary surfaces directed perpendicular to the metal plate plane are provided in the edge region of the cutouts and distributed around the periphery, f) the rubber elastic damping element which is in each case fittable into the cut-out of the metal plates forms a unitary damping body.

13 Arrangement in accordance with claim 10, characterised in that the adjustment of the prestress of the pressure segments takes place through clamping screws.

12. Arrangement in accordance with claim 10, characterised in that the adjustment of the prestress of the pressure segments takes place through driving in clamping wedges.

13. Resilient mounting substantially as herein described with reference to and as illustrated in any one of the accompanying drawings.