Patent Grant
7040941
Field of the Invention
The present invention is in the field of propulsion of watercraft and relates to a vessel propulsion system.
As in all technical fields, also the shipbuilding industry is making an effort to raise the efficiency of a vessel's propulsion system. In addition, especially for inland navigation, there is an increasing need to provide fast vessels that create the smallest possible waves at high speed. It has been demonstrated that waves beating against the shore banks not only impair the reinforcements along them, but also harm the biotopes located at the shore, and in particular disturb the hatching behaviour of birds in habitats nearby.
In addition, especially inland navigation faces the problem of having to avoid pollution caused by lubricants necessarily used for rotating parts of a vessel propulsion system, whereby such lubricants can be released into the water if these parts lie below the water surface during operation of the vessel propulsion system. Almost all known motor or engine driven vessel propulsion systems face this problem.
The object of this invention is to provide an efficient vessel propulsion system that also takes the above problems into account.
This object is solved by a vessel propulsion system according to a first aspect of the present invention exhibiting a propulsion device immersed at least partially in water, which rotates about at least one axis of rotation essentially extending perpendicularly to the direction of propulsion, and which also includes a cover partly enclosing the propulsion device, whereby such cover and the propulsion device together form a water conveying flow channel when the propulsion device is operated.
The vessel propulsion system according to the invention has a propulsion device, for example a rotatably driven wheel or a driven revolving belt. This rotating or revolving propulsion device is enclosed at its outer circumferential surface by a cover which, however, does not enclose the entire circumference of the propulsion device. On the contrary, the propulsion device comes directly into contact with the surrounding water below the waterline of the vessel to be driven. With the vessel propulsion system according to the invention, the distance between the cover and the propulsion device is chosen such that, when the propulsion device is operated, the water surrounding the vessel is conveyed by the propulsion device into the gap between the front end of the propulsion device and the cover and the air therein is forced out of the gap. This applies at least, as described below in more detail, in the case to be considered as a preferred embodiment, where the cover extends below the waterline independent of the loading condition of the vessel and the upper edge of the cover is arranged above the waterline also independent of the loading condition of the vessel—in other words, where also air is at least present between the circumferential surface of the propulsion device and the cover before the propulsion device is operated.
When the propulsion device is operated, the water conveyed by the propulsion device into the gap between the front end of the propulsion device and the cover is conveyed along with the propulsion device in the direction of rotation. Operating the propulsion device thereby results in the formation of a flow channel in the gap, in which the water is being conveyed in the rotating direction of the propulsion device.
The efficiency of the device according to the invention was evaluated in a bollard pull test by its inventor. For such a test, either the vessel or a model thereof is fixed to a bollard, with a load cell mounted in-line, to determine the traction force per unit of power. With conventional propellers commonly also referred to as marine screws, a power output of about 0.023 kg/W can be determined in a bollard pull test of this type. In comparison, the vessel propulsion system according to the invention generated a maximum output of 0.054 kg/W. This maximum output was reached with the vessel propulsion system according to the invention when the flow channel was full of water. Accordingly, the vessel propulsion system according to the invention offers an essentially higher degree of efficiency compared to the known vessel propulsion systems.
Practical experiments have in addition shown that at the same driving performance, i.e. the same speed of the vessel model, the vessel propulsion system according to the invention generated a markedly smaller stern wave than that generated by a conventional propeller drive, which specifically takes the requirement for reduced wave formation, particularly for inland navigation, into account. However, the vessel propulsion system according to the invention can be applied effectively not just for vessels for inland navigation.
Although with the vessel propulsion system according to the invention, for example, a propulsion device revolving in a belt-shaped manner may be provided, which may revolve either on a circular track or in the manner of a tank chain with two opposingly situated linear sections and two opposingly situated semicircular sections, whereby such propulsion device is arranged both outside and inside, at a distance to a casing wall, in a water bearing channel, for simplification of the construction of the vessel propulsion system it is proposed to form the propulsion device with a circumferentially closed circumferential surface. In this case, water circulating in the propulsion direction is, in the radial direction of the propulsion device, exclusively present between the outer circumferential surface of the propulsion device and the cover.
The build-up of a flow channel as fast as possible, that conveys water in the direction opposite to that of the direction of propulsion after starting the propulsion device, is achieved in that the flow channel is narrowly limited laterally. The propulsion device may have appropriate contours on its circumferential surface for this purpose. However, according to a preferred further development and to simplify the constructive embodiment of the vessel propulsion system, it is proposed that the circumferential surface of the propulsion device is bordered laterally with bounding elements extending beyond the circumferential surface and almost up to the cover. These bounding elements can be arranged, according to a preferred further development of the present invention, either stationarily like the cover, for instance directly on the vessel hull, or at least stationarily relative to the vessel hull. Alternatively it is proposed to connect the bounding elements to the rotating propulsion device.
In order to fill the flow channel on starting up the propulsion device, and also from the viewpoint of efficiency, it has been found advantageous to arrange several teeth one behind the other on the outer circumferential surface of the propulsion device.
These teeth should be formed such that they help to transport the water from the surroundings into the gap between the front end of the propulsion device and the cover. The efficiency of the vessel propulsion system with different directions of rotation can be influenced by the teeth geometry. For example, if the vessel propulsion system according to the invention is used in a vessel as a cross-drive for manoeuvring, and if it is therefore important to achieve the same efficiency in both directions of rotation of the propulsion device, preferably teeth with identically formed leading and trailing edges are arranged on the circumferential surface of the propulsion device.
With a vessel propulsion system with a preferential rotation direction as propulsion direction the teeth formed on the outer circumferential surface of the propulsion device are preferably formed similar to saw teeth, i.e. the leading and trailing edges of the teeth have different inclinations. It has been found advantageous for the leading edge directed radially outwards to the tooth tip to have a smaller inclination than that of the trailing edge adjoining such leading edge on the rear side of the tooth tip and from there directed radially inwards. The trailing edge can even have a sharply radial gradient inwards, i.e. it does not contribute to the circumferential surface. The situation is, however, different for the leading edge. By its ramp-shaped gradient, particularly with a rotating direction of propulsion, the surrounding water is to be pressed into the gap between the cover and the circumferential surface of the propulsion device. When the propulsion device is started, such a ramp-shaped inclination of the leading edge accordingly results in a relatively rapid formation of the flow in the flow channel.
Practical experiments have further shown that it is advantageous to form the tips of the teeth with an arcuate profile in the axial direction, as proposed in a preferred further development of the present invention.
Additionally, it has also been found advantageous to form the leading edge and/or the trailing edge of the teeth with an arcuate profile in the axial direction. Moreover, it is preferred to form the leading and/or trailing edges of the teeth with an arcuate convex profile in the circumferential direction, whereby a combination of the two preferred measures mentioned above, i.e. a spherical embodiment of the leading and/or trailing edges, is viewed as advantageous with respect to the efficiency of the vessel propulsion system and also for the avoidance of waves.
As described above, with regard to the starting behaviour of usual motors for vessel propulsion systems, it is preferable to arrange the upper edge of the cover above the vessel waterline and to allow the front and/or rear ends of the cover to extend below the waterline. With such an embodiment, and if the vessel propulsion system is not in operation, air also exists in the gap between the propulsion device and the cover, which is initially forced out by the ingress of water into the gap when the propulsion device is started. As long as there is air in the flow channel, however, the resistance of the propulsion device to rotation is relatively low. This suits the low starting torque of the usual motors in vessel propulsion systems.
With respect to efficiency, it has been found advantageous for the amount of water drawn into the gap between the propulsion device and the cover to be drawn into the gap and removed out of it at a relatively high ratio of horizontal velocity. On the other hand, it should be possible for a specific circumferential section around the propulsion device to freely communicate with the surrounding water. It has been found that the preferred enclosure angle of the cover around the propulsion device is between 200° and 270°. Additionally, according to a preferred further development of the invention, it is proposed that the end of the cover that forms the inlet for the flow channel is formed with a curvature directed forwards and/or that the end of the cover that forms the flow channel's outlet has a curvature directed rearwards. For attaining good efficiency, it has been further found advantageous to provide a minimum gap between the propulsion device and the cover of a size of 2% to 10%, preferably 3% to 6%, of the diameter of the rotating propulsion device. The minimum gap in the previously stated sense, with the preferred embodiment mentioned above with teeth the tips of which have a convex curvature in the axial direction, occurs where the distance between the teeth tips and the cover is at a minimum. It should be noted here that the cover for attaining good efficiency can be formed relatively simple, preferably across from the circumferential surface of the propulsion device, preferably evenly in the axial direction. When a wheel is used as the propulsion device, the cover is thus formed cylindrically but open in one circumferential section.
In view of the best possible effective steering of a vessel provided with the vessel propulsion system, it is further preferred to arrange the propulsion device perpendicular to its axis of rotation and supported rotatably about a steering axis, and to also provide a control device to control the rotation of the propulsion device about the steering axis. With such a preferred embodiment, the driving direction can be influenced by rotating the propulsion device about the steering axis without the need for arranging, in addition, a rudder on the vessel. Furthermore, the maximum efficiency of the propulsion device can be utilized in both the reverse and forward driving directions through appropriate rotation of the propulsion device.
To seal the propulsion device appropriately and simply and, if applicable, a driving motor arranged relatively close to the propulsion device, it is preferred to arrange the propulsion device together with the cover on a support plate through which the propulsion device protrudes, which plate in turn is sealed on top with a hood. The hood, accordingly, encloses at least the propulsion device, but not necessarily a possible motor and lubricated bearings or such. When the vessel propulsion system is operated, occasionally there is water within the hood and in the propulsion device area. Here, however, there are no parts lubricated with lubricant so that no lubricant can be released into the surrounding water from within the hood.
In this preferred further development, the support plate is accommodated in a pan that is rotatably supported in the vessel hull and open on the bottom, and the propulsion device protrudes through it, whereby a seal is provided between the support plate and the pan. This seal can, for example, be formed by a bellows. In this embodiment, the surrounding water comes merely to the underside of the pan, the underside of the cover plate and into the area sealed by the hood. Lubricant contamination of the water through contact with lubricated components can thus be avoided, for example, by making all the bearing components of a drive shaft or axis of rotation watertight by the hood.
The aforementioned preferred embodiment is accordingly further developed preferably in that the hood forms the cover. In this case, the section of the hood radially surrounding the propulsion device serves simultaneously as the cover to limit the gap around the circumference of the propulsion device.
To compensate for the gyroscopic forces generated when the propulsion device rotates under full power, it is further preferred to arrange the support plate with a pivoting means on the pan such that at least one inclination attenuator is connected in-line. The gyroscopic forces that develop when the propulsion device is pivoted about the steering axis can thereby be counteracted through certain pivoting of the support plate against the resistance of the inclination attenuator, thereby preventing these forces from being directly transferred on to the vessel hull.
The behaviour of the vessel propulsion system according to the invention can be controlled, according to a preferred further development, in that a gap setting mechanism is provided for adjustment of the distance between the propulsion device and the cover. With this gap setting mechanism, the height of the flow channel can be altered in the vessel propulsion system according to the invention, for example in order to influence the quantity of water flowing around in the flow channel at a constant motor speed (operating point of the driving motor). Therefore, the formation of waves at the vessel stern can be changed without having to change the operating point of the driving motor.
To adapt the vessel propulsion system to different navigation channel depths, especially for inland navigation, according to a preferred further development of the invention it is proposed to include an immersion depth adjustment device for height adjustment of both the propulsion device and cover. By such an adjustment device the depth to which the propulsion device is immersed in the surrounding water can be influenced without simultaneously altering the gap that forms the flow channel. An immersion depth adjustment device of this type is especially preferred if the propulsion device protrudes beyond the bottom of the vessel hull. In particular, with propulsion devices for vessels navigating in very shallow waters or vessels that run aground with the tides, whose propulsion means, due to this, should nevertheless not be damaged, it is quite conceivable to form the propulsion device such that the axis of rotation extends in the vertical direction, i.e. the propulsion device protrudes through the side of the vessel.
With the usual arrangement of the propulsion device on the underside of the vessel hull, in view of the best possible buoyancy of the vessel, especially for fast driving full glider boats, it is preferable to provide on the front ends of the propulsion device in each case at least one float tapering down from the propulsion device preferably in the axial direction of the axis of rotation. A float tapered in such a way is preferably attached directly to the front end of the propulsion device and has a diameter in this area equal approximately to that of the propulsion device. For reasons of flow dynamics, the diameter tapers in the axial direction of the axis of rotation, whereby the float is formed preferably conical in shape, with an outer surface initially convex in curvature adjoining the propulsion device and followed by a straight outer surface or by one which is concave in curvature. A float formed in this way, preferably formed as an enclosed hollow body, results, however, not only in better buoyancy of the vessel, but also, in addition, raises the vessel during its motion and due to the forces counteracting the float. In order to avoid frictional losses between the oncoming water stream and the float, and thus raise efficiency, it is furthermore preferred to arrange the float such that it is freely rotatable on the axis of rotation or on the drive shaft of the propulsion device.
It has been found advantageous particularly with fast driving full glider boats to provide a thickening on the radial outer end of the propulsion device. This thickening, which is connected to the propulsion device and covers the propulsion device in a mushroom-head-like manner, protrudes beyond the circumference of the float at least partially. It has been found that, due to the high efficiency of the vessel propulsion system according to the invention, vessels formed as glider boats and supported by the buoyancy effect of the floats can rise far enough out of the water at full power that they essentially stay in contact with the water merely through the mushroom-head shaped thickenings. Preferably, the vessel propulsion systems according to the invention are for this purpose provided such that two propulsion systems in each case are arranged at the vessel's front end and two at its rear. In this case, the in total four propulsion devices simultaneously form the propulsive parts at full power as well as those parts which, for example, with a hydroplane, carry the vessel's load on the water. In this regard it is preferred to form the mushroom-head shaped thickening as hydrodynamic as possible such that its outer circumferential surface preferably forms the continuous continuation of the outer circumferential surface of the float.
For the solution of the above object and according to a second aspect of this invention, the generic vessel propulsion system is further developed such that the leading and trailing faces of each of the teeth formed on the propulsion wheel exhibit a spherical, convex surface, that the tip of each tooth is curved convex in the axial direction and that the starting point of the radii of curvature of the spherical surfaces and of the contour of the tooth tip are located in a plane extending orthogonally to the rotational axis of the toothed wheel, the said plane also including the centre point of the propulsion wheel in the axial direction. It has been surprisingly found that this type of formed surface of the propulsion device leads to quite high levels of efficiency. For example, it has been shown during a bollard pull test that a pulling force of 42 kg/kW of engine power is achieved with the vessel propulsion system according to the invention, whereas the corresponding figure for a normal propeller is between 13 and 15 kg/kW.
The relatively high efficiency figures of the vessel propulsion system according to the invention are due to the special design of the teeth formed on the external circumference of the propulsion wheel. With these teeth, the leading and trailing faces are formed spherically convex in the circumferential direction. The leading face is taken to be that face of the tooth forming the front tooth face with rotation of the propulsion wheel in the main propulsion direction, whereas the trailing face is the rear face of the corresponding tooth with rotation in the main propulsion direction.
The propulsion wheel formed according to the second aspect of this invention is further characterised compared to the state of the art in that the tooth tip of each tooth is curved convexly in the axial direction. Finally, the starting points of the radii of curvature of the spherical surfaces of the faces and the contour of the tooth tip are located in a plane extending orthogonally to the rotational axis of the toothed wheel. This plane also includes the centre point of the propulsion wheel in the axial direction, which means that the surfaces of the faces are provided as surfaces of a spherical segment on the external circumferential surface of the propulsion wheel, whereby the point with the highest location in the axial direction of the surface of the spherical segments is situated in each case at the centre of the propulsion wheel. The same requirement is made according to the first aspect of this invention for the contour of the tooth tip. This is also formed symmetrically to the axial centre of the propulsion wheel. The face sides of the propulsion wheel can, for reasons of simple construction, be formed flat. Alternative designs are also possible, such as for example are known from the generic state of the art, the disclosure of which is included in this application through reference.
Preferred further developments of the vessel propulsion system according to the invention and according to the first aspect of this invention are given in the subclaims 2 to 8.
With its third aspect, this invention suggests solutions to the above problem in which the generic vessel propulsion system is further developed in that gusset channels, which are formed between adjacent teeth of the propulsion wheel on its circumferential surface, open axially outwards. The gusset channels, which extend in the axial direction on the circumferential surface of the propulsion wheel and essentially over the tooth base, communicate correspondingly with an intervening space, which is formed between the propulsion wheel and the side surfaces of a housing, which encloses the propulsion wheel and also contains the cover.
It has been found that in particular with those types of vessel propulsion systems which do not have any preferred main direction of propulsion and develop essentially equal thrust in each of the two directions of rotation, the efficiency of the vessel propulsion system can be improved in that during operation of the vessel propulsion system water is passed between the propulsion wheel and the side surfaces of the cover essentially opposite to the force of gravity and is brought into the gusset channels at the side. The corresponding water is, in particular after the forming of a separation-free flow circulating with the drive wheel, passed through the intervening space and to the gap formed between the external circumferential surface of the propulsion wheel and the cover, and namely due to a suction effect which is established only after the formation of a circulating flow. It has been found, compared to the previously known generically regarded solution principle in which side cheeks prevent axial external access to the gusset channels, that this type of design leads to an increased efficiency of the vessel propulsion system.
With regard to a uniform thrust in each of the two directions of rotation, it is also preferable to form the leading and trailing faces essentially the same geometrically and to terminate the inlet and outlet apertures of the gap at approximately the same height.
It has been found to be effective if the volume of the intervening space is matched to the volume of the gap between the external circumferential surface of the propulsion wheel and the cover.
With flat and parallel to one another extending side surfaces of the housing on one side and with the drive wheel on the other side, the volume of the intervening space is calculated from the product of the base area of a truncated circle and the width of the intervening space, i.e. the distance between the side surface of the propulsion wheel on one side and the housing on the other. The truncated circular area has a radius which is given by an addition of the largest outer radius of the propulsion wheel and the smallest height of the gap. With an at least largely constant gap in the circumferential direction, the smallest height of the gap is determined by the distance between the highest point of the tooth tip and the cover. The base area of the truncated circle is determined from a difference of two areas, namely the base area of the circle and a cup-shaped area, one side of which is formed by the outer edge of the circle and the other side of which is formed by a secant, which cuts the circle exactly at the point on its outer side where the enclosure of the propulsion wheel is terminated by the cover. This secant cuts the inlet and outlet apertures, i.e. the corresponding ends of the cover. The volume of the gap can be determined by exact calculation of the gap geometry via the enclosure angle of the cover around the propulsion wheel.
As a simple rule of thumb for the specification of the two-sided volume of the intervening space on one hand and of the gap on the other, a relationship between the width of the propulsion wheel and the width of the intervening space has been established. Here, at least half of the axial extension of the propulsion wheel corresponds to the axial extension of the intervening space.
With regard to the generation of a directed momentum parallel to the direction of travel of the vessel, according to a preferred embodiment of this invention, it is proposed that the cover for the propulsion wheel is provided with a enclosure angle of between 200° and preferably 270°, whereby a region of the cover forming the outlet aperture in the main drive direction of the vessel propulsion system for the flow circulating with the propulsion wheel encloses the propulsion wheel so far that the flow is supplied mainly parallel to the direction of propulsion. Compared with this, a region of the cover forming the inlet of the hydrodynamic drive for the circulating flow in the main direction of propulsion is formed such that the flow is essentially drawn into a gap formed between the cover and the circumferential surface of the propulsion wheel at a speed extending essentially perpendicular to the direction of propulsion. This type of vessel propulsion system, adapted with regard to a high efficiency in the main direction of propulsion, preferably exhibits cheeks which are fitted to the face side of the propulsion wheel and protrude beyond the tooth base to contain at the side the flow forming and circulating in the gap. With this embodiment, the cheeks preferably extend to about the highest point of the tooth tips.
In particular with relatively fast running vessel propulsion systems with a fast running propulsion wheel, it is also preferable if the gap for forming a circulating flow tapers in the region of the outlet opening in the main direction of propulsion, leading to the circulating flow being accelerated on being ejected in the tapered gap and the momentum being increased.
The drawing in of the flow in the surrounding gap is, according to a further preferred embodiment of this invention, promoted in that the gap is widened funnel-shaped in the region of the inlet aperture.
Apart from the tapering outlet aperture and the inlet aperture running funnel-shaped in the direction of flow, the gap is furthermore preferably constant in the circumferential direction over about 90% to 95% of the enclosure angle. It has been found to be particularly effective if the gap is formed, in its section constant in the circumferential direction, with a height corresponding to 0.08 to 0.12, preferably 0.09 to 0.11 of the mean of the three radii of curvature. This gap height is determined from the radial extremity of the tooth tip through to the cover.
Further details, advantages and characteristics of this invention become apparent from the following description of embodiments in conjunction with the drawing, the figures of which show the following:
a–d shows sectional views, containing the axial centre point, of various embodiments of propulsion wheels with 10, 12, 15 or 18 teeth;
The cover 8 is formed cylindrically, i.e. with surfaces extending sideways parallel to the axis of rotation 10. The cover 8 encloses the toothed wheel 6 with an enclosure angle of about 240°. The cover 8 has a front end, i.e. bow end, 12, and a rear end, i.e. stern end, 14. Both ends 12, 14 terminate at about the same height and are flush with the underside of the vessel hull 16. Between the two ends 12, 14, the toothed wheel 6 protrudes beyond the underside of the vessel hull 16.
In the bottom view of the vessel hull 16 according to
The sidewalls 18, 20 form a U-shaped enclosure around the toothed wheel 6, and their undersides are welded to the vessel hull 16. The drive shaft 22 goes through the sidewalls 18, 20 and is sealed against them with appropriate seals. A horizontally extending cross brace 32, running parallel to the axis of rotation 10 of the drive shaft 22, of the hood 34 formed in this way forms the cover 8 partially enclosing the toothed wheel 6 circumferentially. The hood 34 is formed in two parts, whereby the lower part 36 comprises the seal and the duct for the drive shaft 22 and is firmly connected to the vessel hull, whereas the upper part 38, which is connected to and sealed against the lower part 36 with a flange 40, can be removed for maintenance purposes. The location of the joint between the upper part 36 and the lower part 38 is preferably chosen such as to allow the upper part to be removed under any loading condition without water flowing into the vessel hull 16.
In
The toothed wheel 6 exhibits several teeth 46 on its circumferential surface that have a convex gradient in the axial direction relative to the axis of rotation 10. In
Details of the circumferential design of the toothed wheel are recognizable from
Besides the aforementioned convex embodiments in the axial direction, the leading and trailing edges 50, 52, respectively, are also convex-shaped in the circumferential direction. The outcome is that the edges 50, 52 of the respective teeth 46 are formed spherically. The curvature in the axial direction is shown schematically in
The embodiment shown in
The embodiment shown in
Details of this steering arrangement can be seen in
The pan 58 accommodates a support plate 68 which also has a circular recess 70 through which the toothed wheel 6 and the floats 64 protrude. The support plate 68 carries the bearings 24, 26 and also the motor 30.
Between the base plate of the pan 58 and immediately adjacent to the recess 62 and the support plate 68 a seal formed as a bellows 72 is provided which surrounds the recesses 62, 70, thereby hindering the ingress of water between the base plate 68 and the underside of the pan 58 into the latter.
The hood 34 rises from the side of the support plate 68 pointing away from the water. Also in this embodiment, the drive shaft 22 protrudes through the hood 34. The bearings 24, 26 are located outside of hood 34.
Also in this embodiment, the toothed wheel 6 is connected to the drive shaft 22 in a torsionally rigid manner, and the bounding elements 42, 44 are likewise provided torsionally rigid to the toothed wheel 6. Located adjacent to the sides of the bounding elements 42, 44 are the respective floats 64 which, through the bearings 74, are supported on the drive shaft 22 in a freely rotatable manner.
The floats 64 are essentially formed identically and have, adjacent to the toothed wheel 6, a diameter which approximately corresponds to that of the latter. The outer contour of the floats 64 is formed as follows in the embodiment shown: A first circumferential section 76 extends parallel to the axis of rotation 10, followed by a second circumferential section 78 which essentially has a plane contour running towards the axis of rotation 10. This second circumferential section 78 can, in view of a buoyancy as great as possible of the floats 64 immersed in water, also be formed in an outwardly convex-shaped manner. The first circumferential section 76 is, on its circumference, surrounded by a thickening 80 firmly connected to the toothed wheel 6. The inside of this thickening 80 is cylindrically formed. The thickening 80 extends on both sides of the toothed wheel 6 and the allocated bounding elements 42, 44 and appears in mushroom-head shape in the sectional view shown in
The support plate 68 is held in the pan 58 and is supported in a pivoted manner relative to the latter, and more specifically by the in-line arrangement of at least one inclination attenuator 82 formed as a conventional telescopic damper. One end of the attenuator 82 is connected to the upper end of the sidewall 60, whereas its other end is linked close to the support plate 68.
The inclination attenuator 82 serves to dampen pivoting movements about a pivot axis extending, in the embodiment shown, in the longitudinal direction of the vessel. The support plate 68 is supported by bearings at its front and rear ends, seen in the propulsion direction, such that it can be pivoted for these pivoting movements. The pivot axis formed in this way runs, in each case, rectangularly to the axis of rotation of the motor 30 and the steering axis S and intersects the two axes at their common point of intersection. With the embodiment shown, this point of intersection is the centre of the toothed wheel 6.
With respect to the embodiment of the gap 54 between the bounding elements 42, 44, the embodiment shown in
When the vessel propulsion system shown in
a–c show various embodiments of propulsion wheels 100 of the vessel propulsion system according to the invention with 10 teeth (
The radii of curvature of tooth base 108, 110, the leading face 104 and the trailing face 106 are in each case identical in the illustrated embodiments. The starting point of the relevant radii of curvature (in each case R=75 mm) of the embodiments shown in
The co-ordinates for the base XG, YG apply both to the tooth base 108 and to the tooth base 110. The radius of curvature of the tooth tip in the axial direction is given by the intersection points of the leading and trailing faces 104, 106. The propulsion wheel 100 with 18 teeth has been found to be particularly advantageous.
With the formation of the propulsion wheel 100, which is described in detail with reference to
The housing 120 exhibits a cover 126 which extends parallel to the drive shaft 114. As can be seen, particularly in
With the embodiment illustrated in
With the operation of the embodiment the water surrounding the vessel's hull 134 is carried along with the rotation of the propulsion wheel 100 in the main propulsion direction H until on the conclusion of a start-up process a flow circulating with the propulsion wheel 100 is established in the gap 132. The side cheeks 136 stabilise the continuous, separation-free circulating flow in the gap 132. Practical experiments have shown that on reaching the operating point, i.e. after complete elimination of air located above the water surface W in the idle state from the gap 132, additionally water flows through an intervening space 138 between the side surfaces of the propulsion wheel and the side surfaces 116, 118 of the housing, filling it up. The ensuing phenomena cannot at present be fully described theoretically. It has also been found that the intervening space 138 must have a certain volume which is matched to the volume of the gap. The volume of the intervening space 138 is calculated from a base area, which is shown hatched in
The gap volume is calculated from the gap area in a gap, which where necessary is only constant in sections, and the enclosure section of the gap.
As can be seen in
The ratio of the volume of the intervening space 138 to the volume of the gap 132 is preferably between 0.75 and 1.25, especially preferably between 0.9 and 1.1.
With the embodiment illustrated in
The embodiment of a vessel propulsion system illustrated in
The embodiment illustrated in
With the embodiment in which the gusset channels communicate axially with the intervening space, the surface shape of the propulsion wheel is not restricted to the spherical shape claimed with the first aspect of this invention. It is therefore also possible to form the propulsion wheel by a wide cylindrical roller with any tooth geometry. In the design of the propulsion wheel it is essential according to the current position of the applicant only that the propulsion wheel exhibits a tooth arrangement on its outer circumferential surface, the said tooth arrangement displacing the surrounding water in order to form a flow circulating in the circumferential direction in the gap. In the sense of the invention, the propulsion wheel can in this case be taken to mean a means of propulsion which is formed by a circulating band. Whereas with the embodiments a propulsion wheel is illustrated arranged in each case on the drive shaft, also a number of propulsion bodies next to one another can be mounted on the drive shaft for the realisation of the vessel propulsion system according to the invention, which with a relatively simple method of construction leads to an increase in the efficiency due to greater amounts of flow for the same power.
| Number | Date | Country | Kind |
|---|---|---|---|
| 101 04 680 | Feb 2001 | DE | national |
This application is a continuation-in-part of the International Application No. PCT/EP02/00562 filed Jan. 21, 2002, based on the German priority Application No. 101.04680.4 filed Feb. 2, 2001, and includes the new subject matter contained in the German application No. filed Jul. 29, 2003.
| Number | Name | Date | Kind |
|---|---|---|---|
| 100820 | Tucker | Mar 1870 | A |
| 175405 | Bardwell | Mar 1876 | A |
| 1701925 | Kisevalter | Feb 1929 | A |
| 3166039 | Weymouth | Jan 1965 | A |
| 3628493 | Headrick | Dec 1971 | A |
| 3884176 | Riddle | May 1975 | A |
| 4004544 | Moore | Jan 1977 | A |
| 4846091 | Ives | Jul 1989 | A |
| 5013269 | Legoy et al. | May 1991 | A |
| Number | Date | Country |
|---|---|---|
| 755483 | Nov 1933 | FR |
| 251869 | May 1926 | GB |
| WO 9929568 | Jun 1999 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 20060046587 A1 | Mar 2006 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/EP02/00562 | Jan 2002 | US |
| Child | 10632153 | US |
